1 // SPDX-License-Identifier: GPL-2.0-or-later
2 // SPI init/core code
3 //
4 // Copyright (C) 2005 David Brownell
5 // Copyright (C) 2008 Secret Lab Technologies Ltd.
6
7 #include <linux/kernel.h>
8 #include <linux/device.h>
9 #include <linux/init.h>
10 #include <linux/cache.h>
11 #include <linux/dma-mapping.h>
12 #include <linux/dmaengine.h>
13 #include <linux/mutex.h>
14 #include <linux/of_device.h>
15 #include <linux/of_irq.h>
16 #include <linux/clk/clk-conf.h>
17 #include <linux/slab.h>
18 #include <linux/mod_devicetable.h>
19 #include <linux/spi/spi.h>
20 #include <linux/spi/spi-mem.h>
21 #include <linux/of_gpio.h>
22 #include <linux/gpio/consumer.h>
23 #include <linux/pm_runtime.h>
24 #include <linux/pm_domain.h>
25 #include <linux/property.h>
26 #include <linux/export.h>
27 #include <linux/sched/rt.h>
28 #include <uapi/linux/sched/types.h>
29 #include <linux/delay.h>
30 #include <linux/kthread.h>
31 #include <linux/ioport.h>
32 #include <linux/acpi.h>
33 #include <linux/highmem.h>
34 #include <linux/idr.h>
35 #include <linux/platform_data/x86/apple.h>
36
37 #define CREATE_TRACE_POINTS
38 #include <trace/events/spi.h>
39 EXPORT_TRACEPOINT_SYMBOL(spi_transfer_start);
40 EXPORT_TRACEPOINT_SYMBOL(spi_transfer_stop);
41
42 #include "internals.h"
43
44 static DEFINE_IDR(spi_master_idr);
45
spidev_release(struct device * dev)46 static void spidev_release(struct device *dev)
47 {
48 struct spi_device *spi = to_spi_device(dev);
49
50 /* spi controllers may cleanup for released devices */
51 if (spi->controller->cleanup)
52 spi->controller->cleanup(spi);
53
54 spi_controller_put(spi->controller);
55 kfree(spi->driver_override);
56 kfree(spi);
57 }
58
59 static ssize_t
modalias_show(struct device * dev,struct device_attribute * a,char * buf)60 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
61 {
62 const struct spi_device *spi = to_spi_device(dev);
63 int len;
64
65 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
66 if (len != -ENODEV)
67 return len;
68
69 return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
70 }
71 static DEVICE_ATTR_RO(modalias);
72
driver_override_store(struct device * dev,struct device_attribute * a,const char * buf,size_t count)73 static ssize_t driver_override_store(struct device *dev,
74 struct device_attribute *a,
75 const char *buf, size_t count)
76 {
77 struct spi_device *spi = to_spi_device(dev);
78 const char *end = memchr(buf, '\n', count);
79 const size_t len = end ? end - buf : count;
80 const char *driver_override, *old;
81
82 /* We need to keep extra room for a newline when displaying value */
83 if (len >= (PAGE_SIZE - 1))
84 return -EINVAL;
85
86 driver_override = kstrndup(buf, len, GFP_KERNEL);
87 if (!driver_override)
88 return -ENOMEM;
89
90 device_lock(dev);
91 old = spi->driver_override;
92 if (len) {
93 spi->driver_override = driver_override;
94 } else {
95 /* Empty string, disable driver override */
96 spi->driver_override = NULL;
97 kfree(driver_override);
98 }
99 device_unlock(dev);
100 kfree(old);
101
102 return count;
103 }
104
driver_override_show(struct device * dev,struct device_attribute * a,char * buf)105 static ssize_t driver_override_show(struct device *dev,
106 struct device_attribute *a, char *buf)
107 {
108 const struct spi_device *spi = to_spi_device(dev);
109 ssize_t len;
110
111 device_lock(dev);
112 len = snprintf(buf, PAGE_SIZE, "%s\n", spi->driver_override ? : "");
113 device_unlock(dev);
114 return len;
115 }
116 static DEVICE_ATTR_RW(driver_override);
117
118 #define SPI_STATISTICS_ATTRS(field, file) \
119 static ssize_t spi_controller_##field##_show(struct device *dev, \
120 struct device_attribute *attr, \
121 char *buf) \
122 { \
123 struct spi_controller *ctlr = container_of(dev, \
124 struct spi_controller, dev); \
125 return spi_statistics_##field##_show(&ctlr->statistics, buf); \
126 } \
127 static struct device_attribute dev_attr_spi_controller_##field = { \
128 .attr = { .name = file, .mode = 0444 }, \
129 .show = spi_controller_##field##_show, \
130 }; \
131 static ssize_t spi_device_##field##_show(struct device *dev, \
132 struct device_attribute *attr, \
133 char *buf) \
134 { \
135 struct spi_device *spi = to_spi_device(dev); \
136 return spi_statistics_##field##_show(&spi->statistics, buf); \
137 } \
138 static struct device_attribute dev_attr_spi_device_##field = { \
139 .attr = { .name = file, .mode = 0444 }, \
140 .show = spi_device_##field##_show, \
141 }
142
143 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string) \
144 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
145 char *buf) \
146 { \
147 unsigned long flags; \
148 ssize_t len; \
149 spin_lock_irqsave(&stat->lock, flags); \
150 len = sprintf(buf, format_string, stat->field); \
151 spin_unlock_irqrestore(&stat->lock, flags); \
152 return len; \
153 } \
154 SPI_STATISTICS_ATTRS(name, file)
155
156 #define SPI_STATISTICS_SHOW(field, format_string) \
157 SPI_STATISTICS_SHOW_NAME(field, __stringify(field), \
158 field, format_string)
159
160 SPI_STATISTICS_SHOW(messages, "%lu");
161 SPI_STATISTICS_SHOW(transfers, "%lu");
162 SPI_STATISTICS_SHOW(errors, "%lu");
163 SPI_STATISTICS_SHOW(timedout, "%lu");
164
165 SPI_STATISTICS_SHOW(spi_sync, "%lu");
166 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
167 SPI_STATISTICS_SHOW(spi_async, "%lu");
168
169 SPI_STATISTICS_SHOW(bytes, "%llu");
170 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
171 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
172
173 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number) \
174 SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index, \
175 "transfer_bytes_histo_" number, \
176 transfer_bytes_histo[index], "%lu")
177 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0, "0-1");
178 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1, "2-3");
179 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2, "4-7");
180 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3, "8-15");
181 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4, "16-31");
182 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5, "32-63");
183 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6, "64-127");
184 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7, "128-255");
185 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8, "256-511");
186 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9, "512-1023");
187 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
188 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
189 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
190 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
191 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
192 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
193 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
194
195 SPI_STATISTICS_SHOW(transfers_split_maxsize, "%lu");
196
197 static struct attribute *spi_dev_attrs[] = {
198 &dev_attr_modalias.attr,
199 &dev_attr_driver_override.attr,
200 NULL,
201 };
202
203 static const struct attribute_group spi_dev_group = {
204 .attrs = spi_dev_attrs,
205 };
206
207 static struct attribute *spi_device_statistics_attrs[] = {
208 &dev_attr_spi_device_messages.attr,
209 &dev_attr_spi_device_transfers.attr,
210 &dev_attr_spi_device_errors.attr,
211 &dev_attr_spi_device_timedout.attr,
212 &dev_attr_spi_device_spi_sync.attr,
213 &dev_attr_spi_device_spi_sync_immediate.attr,
214 &dev_attr_spi_device_spi_async.attr,
215 &dev_attr_spi_device_bytes.attr,
216 &dev_attr_spi_device_bytes_rx.attr,
217 &dev_attr_spi_device_bytes_tx.attr,
218 &dev_attr_spi_device_transfer_bytes_histo0.attr,
219 &dev_attr_spi_device_transfer_bytes_histo1.attr,
220 &dev_attr_spi_device_transfer_bytes_histo2.attr,
221 &dev_attr_spi_device_transfer_bytes_histo3.attr,
222 &dev_attr_spi_device_transfer_bytes_histo4.attr,
223 &dev_attr_spi_device_transfer_bytes_histo5.attr,
224 &dev_attr_spi_device_transfer_bytes_histo6.attr,
225 &dev_attr_spi_device_transfer_bytes_histo7.attr,
226 &dev_attr_spi_device_transfer_bytes_histo8.attr,
227 &dev_attr_spi_device_transfer_bytes_histo9.attr,
228 &dev_attr_spi_device_transfer_bytes_histo10.attr,
229 &dev_attr_spi_device_transfer_bytes_histo11.attr,
230 &dev_attr_spi_device_transfer_bytes_histo12.attr,
231 &dev_attr_spi_device_transfer_bytes_histo13.attr,
232 &dev_attr_spi_device_transfer_bytes_histo14.attr,
233 &dev_attr_spi_device_transfer_bytes_histo15.attr,
234 &dev_attr_spi_device_transfer_bytes_histo16.attr,
235 &dev_attr_spi_device_transfers_split_maxsize.attr,
236 NULL,
237 };
238
239 static const struct attribute_group spi_device_statistics_group = {
240 .name = "statistics",
241 .attrs = spi_device_statistics_attrs,
242 };
243
244 static const struct attribute_group *spi_dev_groups[] = {
245 &spi_dev_group,
246 &spi_device_statistics_group,
247 NULL,
248 };
249
250 static struct attribute *spi_controller_statistics_attrs[] = {
251 &dev_attr_spi_controller_messages.attr,
252 &dev_attr_spi_controller_transfers.attr,
253 &dev_attr_spi_controller_errors.attr,
254 &dev_attr_spi_controller_timedout.attr,
255 &dev_attr_spi_controller_spi_sync.attr,
256 &dev_attr_spi_controller_spi_sync_immediate.attr,
257 &dev_attr_spi_controller_spi_async.attr,
258 &dev_attr_spi_controller_bytes.attr,
259 &dev_attr_spi_controller_bytes_rx.attr,
260 &dev_attr_spi_controller_bytes_tx.attr,
261 &dev_attr_spi_controller_transfer_bytes_histo0.attr,
262 &dev_attr_spi_controller_transfer_bytes_histo1.attr,
263 &dev_attr_spi_controller_transfer_bytes_histo2.attr,
264 &dev_attr_spi_controller_transfer_bytes_histo3.attr,
265 &dev_attr_spi_controller_transfer_bytes_histo4.attr,
266 &dev_attr_spi_controller_transfer_bytes_histo5.attr,
267 &dev_attr_spi_controller_transfer_bytes_histo6.attr,
268 &dev_attr_spi_controller_transfer_bytes_histo7.attr,
269 &dev_attr_spi_controller_transfer_bytes_histo8.attr,
270 &dev_attr_spi_controller_transfer_bytes_histo9.attr,
271 &dev_attr_spi_controller_transfer_bytes_histo10.attr,
272 &dev_attr_spi_controller_transfer_bytes_histo11.attr,
273 &dev_attr_spi_controller_transfer_bytes_histo12.attr,
274 &dev_attr_spi_controller_transfer_bytes_histo13.attr,
275 &dev_attr_spi_controller_transfer_bytes_histo14.attr,
276 &dev_attr_spi_controller_transfer_bytes_histo15.attr,
277 &dev_attr_spi_controller_transfer_bytes_histo16.attr,
278 &dev_attr_spi_controller_transfers_split_maxsize.attr,
279 NULL,
280 };
281
282 static const struct attribute_group spi_controller_statistics_group = {
283 .name = "statistics",
284 .attrs = spi_controller_statistics_attrs,
285 };
286
287 static const struct attribute_group *spi_master_groups[] = {
288 &spi_controller_statistics_group,
289 NULL,
290 };
291
spi_statistics_add_transfer_stats(struct spi_statistics * stats,struct spi_transfer * xfer,struct spi_controller * ctlr)292 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
293 struct spi_transfer *xfer,
294 struct spi_controller *ctlr)
295 {
296 unsigned long flags;
297 int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
298
299 if (l2len < 0)
300 l2len = 0;
301
302 spin_lock_irqsave(&stats->lock, flags);
303
304 stats->transfers++;
305 stats->transfer_bytes_histo[l2len]++;
306
307 stats->bytes += xfer->len;
308 if ((xfer->tx_buf) &&
309 (xfer->tx_buf != ctlr->dummy_tx))
310 stats->bytes_tx += xfer->len;
311 if ((xfer->rx_buf) &&
312 (xfer->rx_buf != ctlr->dummy_rx))
313 stats->bytes_rx += xfer->len;
314
315 spin_unlock_irqrestore(&stats->lock, flags);
316 }
317 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
318
319 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
320 * and the sysfs version makes coldplug work too.
321 */
322
spi_match_id(const struct spi_device_id * id,const struct spi_device * sdev)323 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
324 const struct spi_device *sdev)
325 {
326 while (id->name[0]) {
327 if (!strcmp(sdev->modalias, id->name))
328 return id;
329 id++;
330 }
331 return NULL;
332 }
333
spi_get_device_id(const struct spi_device * sdev)334 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
335 {
336 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
337
338 return spi_match_id(sdrv->id_table, sdev);
339 }
340 EXPORT_SYMBOL_GPL(spi_get_device_id);
341
spi_match_device(struct device * dev,struct device_driver * drv)342 static int spi_match_device(struct device *dev, struct device_driver *drv)
343 {
344 const struct spi_device *spi = to_spi_device(dev);
345 const struct spi_driver *sdrv = to_spi_driver(drv);
346
347 /* Check override first, and if set, only use the named driver */
348 if (spi->driver_override)
349 return strcmp(spi->driver_override, drv->name) == 0;
350
351 /* Attempt an OF style match */
352 if (of_driver_match_device(dev, drv))
353 return 1;
354
355 /* Then try ACPI */
356 if (acpi_driver_match_device(dev, drv))
357 return 1;
358
359 if (sdrv->id_table)
360 return !!spi_match_id(sdrv->id_table, spi);
361
362 return strcmp(spi->modalias, drv->name) == 0;
363 }
364
spi_uevent(struct device * dev,struct kobj_uevent_env * env)365 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
366 {
367 const struct spi_device *spi = to_spi_device(dev);
368 int rc;
369
370 rc = acpi_device_uevent_modalias(dev, env);
371 if (rc != -ENODEV)
372 return rc;
373
374 return add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
375 }
376
spi_probe(struct device * dev)377 static int spi_probe(struct device *dev)
378 {
379 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
380 struct spi_device *spi = to_spi_device(dev);
381 int ret;
382
383 ret = of_clk_set_defaults(dev->of_node, false);
384 if (ret)
385 return ret;
386
387 if (dev->of_node) {
388 spi->irq = of_irq_get(dev->of_node, 0);
389 if (spi->irq == -EPROBE_DEFER)
390 return -EPROBE_DEFER;
391 if (spi->irq < 0)
392 spi->irq = 0;
393 }
394
395 ret = dev_pm_domain_attach(dev, true);
396 if (ret)
397 return ret;
398
399 if (sdrv->probe) {
400 ret = sdrv->probe(spi);
401 if (ret)
402 dev_pm_domain_detach(dev, true);
403 }
404
405 return ret;
406 }
407
spi_remove(struct device * dev)408 static int spi_remove(struct device *dev)
409 {
410 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
411
412 if (sdrv->remove) {
413 int ret;
414
415 ret = sdrv->remove(to_spi_device(dev));
416 if (ret)
417 dev_warn(dev,
418 "Failed to unbind driver (%pe), ignoring\n",
419 ERR_PTR(ret));
420 }
421
422 dev_pm_domain_detach(dev, true);
423
424 return 0;
425 }
426
spi_shutdown(struct device * dev)427 static void spi_shutdown(struct device *dev)
428 {
429 if (dev->driver) {
430 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
431
432 if (sdrv->shutdown)
433 sdrv->shutdown(to_spi_device(dev));
434 }
435 }
436
437 struct bus_type spi_bus_type = {
438 .name = "spi",
439 .dev_groups = spi_dev_groups,
440 .match = spi_match_device,
441 .uevent = spi_uevent,
442 .probe = spi_probe,
443 .remove = spi_remove,
444 .shutdown = spi_shutdown,
445 };
446 EXPORT_SYMBOL_GPL(spi_bus_type);
447
448 /**
449 * __spi_register_driver - register a SPI driver
450 * @owner: owner module of the driver to register
451 * @sdrv: the driver to register
452 * Context: can sleep
453 *
454 * Return: zero on success, else a negative error code.
455 */
__spi_register_driver(struct module * owner,struct spi_driver * sdrv)456 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
457 {
458 sdrv->driver.owner = owner;
459 sdrv->driver.bus = &spi_bus_type;
460 return driver_register(&sdrv->driver);
461 }
462 EXPORT_SYMBOL_GPL(__spi_register_driver);
463
464 /*-------------------------------------------------------------------------*/
465
466 /* SPI devices should normally not be created by SPI device drivers; that
467 * would make them board-specific. Similarly with SPI controller drivers.
468 * Device registration normally goes into like arch/.../mach.../board-YYY.c
469 * with other readonly (flashable) information about mainboard devices.
470 */
471
472 struct boardinfo {
473 struct list_head list;
474 struct spi_board_info board_info;
475 };
476
477 static LIST_HEAD(board_list);
478 static LIST_HEAD(spi_controller_list);
479
480 /*
481 * Used to protect add/del operation for board_info list and
482 * spi_controller list, and their matching process
483 * also used to protect object of type struct idr
484 */
485 static DEFINE_MUTEX(board_lock);
486
487 /*
488 * Prevents addition of devices with same chip select and
489 * addition of devices below an unregistering controller.
490 */
491 static DEFINE_MUTEX(spi_add_lock);
492
493 /**
494 * spi_alloc_device - Allocate a new SPI device
495 * @ctlr: Controller to which device is connected
496 * Context: can sleep
497 *
498 * Allows a driver to allocate and initialize a spi_device without
499 * registering it immediately. This allows a driver to directly
500 * fill the spi_device with device parameters before calling
501 * spi_add_device() on it.
502 *
503 * Caller is responsible to call spi_add_device() on the returned
504 * spi_device structure to add it to the SPI controller. If the caller
505 * needs to discard the spi_device without adding it, then it should
506 * call spi_dev_put() on it.
507 *
508 * Return: a pointer to the new device, or NULL.
509 */
spi_alloc_device(struct spi_controller * ctlr)510 struct spi_device *spi_alloc_device(struct spi_controller *ctlr)
511 {
512 struct spi_device *spi;
513
514 if (!spi_controller_get(ctlr))
515 return NULL;
516
517 spi = kzalloc(sizeof(*spi), GFP_KERNEL);
518 if (!spi) {
519 spi_controller_put(ctlr);
520 return NULL;
521 }
522
523 spi->master = spi->controller = ctlr;
524 spi->dev.parent = &ctlr->dev;
525 spi->dev.bus = &spi_bus_type;
526 spi->dev.release = spidev_release;
527 spi->cs_gpio = -ENOENT;
528 spi->mode = ctlr->buswidth_override_bits;
529
530 spin_lock_init(&spi->statistics.lock);
531
532 device_initialize(&spi->dev);
533 return spi;
534 }
535 EXPORT_SYMBOL_GPL(spi_alloc_device);
536
spi_dev_set_name(struct spi_device * spi)537 static void spi_dev_set_name(struct spi_device *spi)
538 {
539 struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
540
541 if (adev) {
542 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
543 return;
544 }
545
546 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->controller->dev),
547 spi->chip_select);
548 }
549
spi_dev_check(struct device * dev,void * data)550 static int spi_dev_check(struct device *dev, void *data)
551 {
552 struct spi_device *spi = to_spi_device(dev);
553 struct spi_device *new_spi = data;
554
555 if (spi->controller == new_spi->controller &&
556 spi->chip_select == new_spi->chip_select)
557 return -EBUSY;
558 return 0;
559 }
560
561 /**
562 * spi_add_device - Add spi_device allocated with spi_alloc_device
563 * @spi: spi_device to register
564 *
565 * Companion function to spi_alloc_device. Devices allocated with
566 * spi_alloc_device can be added onto the spi bus with this function.
567 *
568 * Return: 0 on success; negative errno on failure
569 */
spi_add_device(struct spi_device * spi)570 int spi_add_device(struct spi_device *spi)
571 {
572 struct spi_controller *ctlr = spi->controller;
573 struct device *dev = ctlr->dev.parent;
574 int status;
575
576 /* Chipselects are numbered 0..max; validate. */
577 if (spi->chip_select >= ctlr->num_chipselect) {
578 dev_err(dev, "cs%d >= max %d\n", spi->chip_select,
579 ctlr->num_chipselect);
580 return -EINVAL;
581 }
582
583 /* Set the bus ID string */
584 spi_dev_set_name(spi);
585
586 /* We need to make sure there's no other device with this
587 * chipselect **BEFORE** we call setup(), else we'll trash
588 * its configuration. Lock against concurrent add() calls.
589 */
590 mutex_lock(&spi_add_lock);
591
592 status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
593 if (status) {
594 dev_err(dev, "chipselect %d already in use\n",
595 spi->chip_select);
596 goto done;
597 }
598
599 /* Controller may unregister concurrently */
600 if (IS_ENABLED(CONFIG_SPI_DYNAMIC) &&
601 !device_is_registered(&ctlr->dev)) {
602 status = -ENODEV;
603 goto done;
604 }
605
606 /* Descriptors take precedence */
607 if (ctlr->cs_gpiods)
608 spi->cs_gpiod = ctlr->cs_gpiods[spi->chip_select];
609 else if (ctlr->cs_gpios)
610 spi->cs_gpio = ctlr->cs_gpios[spi->chip_select];
611
612 /* Drivers may modify this initial i/o setup, but will
613 * normally rely on the device being setup. Devices
614 * using SPI_CS_HIGH can't coexist well otherwise...
615 */
616 status = spi_setup(spi);
617 if (status < 0) {
618 dev_err(dev, "can't setup %s, status %d\n",
619 dev_name(&spi->dev), status);
620 goto done;
621 }
622
623 /* Device may be bound to an active driver when this returns */
624 status = device_add(&spi->dev);
625 if (status < 0)
626 dev_err(dev, "can't add %s, status %d\n",
627 dev_name(&spi->dev), status);
628 else
629 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
630
631 done:
632 mutex_unlock(&spi_add_lock);
633 return status;
634 }
635 EXPORT_SYMBOL_GPL(spi_add_device);
636
637 /**
638 * spi_new_device - instantiate one new SPI device
639 * @ctlr: Controller to which device is connected
640 * @chip: Describes the SPI device
641 * Context: can sleep
642 *
643 * On typical mainboards, this is purely internal; and it's not needed
644 * after board init creates the hard-wired devices. Some development
645 * platforms may not be able to use spi_register_board_info though, and
646 * this is exported so that for example a USB or parport based adapter
647 * driver could add devices (which it would learn about out-of-band).
648 *
649 * Return: the new device, or NULL.
650 */
spi_new_device(struct spi_controller * ctlr,struct spi_board_info * chip)651 struct spi_device *spi_new_device(struct spi_controller *ctlr,
652 struct spi_board_info *chip)
653 {
654 struct spi_device *proxy;
655 int status;
656
657 /* NOTE: caller did any chip->bus_num checks necessary.
658 *
659 * Also, unless we change the return value convention to use
660 * error-or-pointer (not NULL-or-pointer), troubleshootability
661 * suggests syslogged diagnostics are best here (ugh).
662 */
663
664 proxy = spi_alloc_device(ctlr);
665 if (!proxy)
666 return NULL;
667
668 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
669
670 proxy->chip_select = chip->chip_select;
671 proxy->max_speed_hz = chip->max_speed_hz;
672 proxy->mode = chip->mode;
673 proxy->irq = chip->irq;
674 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
675 proxy->dev.platform_data = (void *) chip->platform_data;
676 proxy->controller_data = chip->controller_data;
677 proxy->controller_state = NULL;
678
679 if (chip->swnode) {
680 status = device_add_software_node(&proxy->dev, chip->swnode);
681 if (status) {
682 dev_err(&ctlr->dev, "failed to add software node to '%s': %d\n",
683 chip->modalias, status);
684 goto err_dev_put;
685 }
686 }
687
688 status = spi_add_device(proxy);
689 if (status < 0)
690 goto err_dev_put;
691
692 return proxy;
693
694 err_dev_put:
695 device_remove_software_node(&proxy->dev);
696 spi_dev_put(proxy);
697 return NULL;
698 }
699 EXPORT_SYMBOL_GPL(spi_new_device);
700
701 /**
702 * spi_unregister_device - unregister a single SPI device
703 * @spi: spi_device to unregister
704 *
705 * Start making the passed SPI device vanish. Normally this would be handled
706 * by spi_unregister_controller().
707 */
spi_unregister_device(struct spi_device * spi)708 void spi_unregister_device(struct spi_device *spi)
709 {
710 if (!spi)
711 return;
712
713 if (spi->dev.of_node) {
714 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
715 of_node_put(spi->dev.of_node);
716 }
717 if (ACPI_COMPANION(&spi->dev))
718 acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
719 device_remove_software_node(&spi->dev);
720 device_unregister(&spi->dev);
721 }
722 EXPORT_SYMBOL_GPL(spi_unregister_device);
723
spi_match_controller_to_boardinfo(struct spi_controller * ctlr,struct spi_board_info * bi)724 static void spi_match_controller_to_boardinfo(struct spi_controller *ctlr,
725 struct spi_board_info *bi)
726 {
727 struct spi_device *dev;
728
729 if (ctlr->bus_num != bi->bus_num)
730 return;
731
732 dev = spi_new_device(ctlr, bi);
733 if (!dev)
734 dev_err(ctlr->dev.parent, "can't create new device for %s\n",
735 bi->modalias);
736 }
737
738 /**
739 * spi_register_board_info - register SPI devices for a given board
740 * @info: array of chip descriptors
741 * @n: how many descriptors are provided
742 * Context: can sleep
743 *
744 * Board-specific early init code calls this (probably during arch_initcall)
745 * with segments of the SPI device table. Any device nodes are created later,
746 * after the relevant parent SPI controller (bus_num) is defined. We keep
747 * this table of devices forever, so that reloading a controller driver will
748 * not make Linux forget about these hard-wired devices.
749 *
750 * Other code can also call this, e.g. a particular add-on board might provide
751 * SPI devices through its expansion connector, so code initializing that board
752 * would naturally declare its SPI devices.
753 *
754 * The board info passed can safely be __initdata ... but be careful of
755 * any embedded pointers (platform_data, etc), they're copied as-is.
756 *
757 * Return: zero on success, else a negative error code.
758 */
spi_register_board_info(struct spi_board_info const * info,unsigned n)759 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
760 {
761 struct boardinfo *bi;
762 int i;
763
764 if (!n)
765 return 0;
766
767 bi = kcalloc(n, sizeof(*bi), GFP_KERNEL);
768 if (!bi)
769 return -ENOMEM;
770
771 for (i = 0; i < n; i++, bi++, info++) {
772 struct spi_controller *ctlr;
773
774 memcpy(&bi->board_info, info, sizeof(*info));
775
776 mutex_lock(&board_lock);
777 list_add_tail(&bi->list, &board_list);
778 list_for_each_entry(ctlr, &spi_controller_list, list)
779 spi_match_controller_to_boardinfo(ctlr,
780 &bi->board_info);
781 mutex_unlock(&board_lock);
782 }
783
784 return 0;
785 }
786
787 /*-------------------------------------------------------------------------*/
788
spi_set_cs(struct spi_device * spi,bool enable,bool force)789 static void spi_set_cs(struct spi_device *spi, bool enable, bool force)
790 {
791 bool activate = enable;
792
793 /*
794 * Avoid calling into the driver (or doing delays) if the chip select
795 * isn't actually changing from the last time this was called.
796 */
797 if (!force && (spi->controller->last_cs_enable == enable) &&
798 (spi->controller->last_cs_mode_high == (spi->mode & SPI_CS_HIGH)))
799 return;
800
801 spi->controller->last_cs_enable = enable;
802 spi->controller->last_cs_mode_high = spi->mode & SPI_CS_HIGH;
803
804 if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio) ||
805 !spi->controller->set_cs_timing) {
806 if (activate)
807 spi_delay_exec(&spi->controller->cs_setup, NULL);
808 else
809 spi_delay_exec(&spi->controller->cs_hold, NULL);
810 }
811
812 if (spi->mode & SPI_CS_HIGH)
813 enable = !enable;
814
815 if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio)) {
816 if (!(spi->mode & SPI_NO_CS)) {
817 if (spi->cs_gpiod)
818 /* polarity handled by gpiolib */
819 gpiod_set_value_cansleep(spi->cs_gpiod, activate);
820 else
821 /*
822 * invert the enable line, as active low is
823 * default for SPI.
824 */
825 gpio_set_value_cansleep(spi->cs_gpio, !enable);
826 }
827 /* Some SPI masters need both GPIO CS & slave_select */
828 if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&
829 spi->controller->set_cs)
830 spi->controller->set_cs(spi, !enable);
831 } else if (spi->controller->set_cs) {
832 spi->controller->set_cs(spi, !enable);
833 }
834
835 if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio) ||
836 !spi->controller->set_cs_timing) {
837 if (!activate)
838 spi_delay_exec(&spi->controller->cs_inactive, NULL);
839 }
840 }
841
842 #ifdef CONFIG_HAS_DMA
spi_map_buf(struct spi_controller * ctlr,struct device * dev,struct sg_table * sgt,void * buf,size_t len,enum dma_data_direction dir)843 int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
844 struct sg_table *sgt, void *buf, size_t len,
845 enum dma_data_direction dir)
846 {
847 const bool vmalloced_buf = is_vmalloc_addr(buf);
848 unsigned int max_seg_size = dma_get_max_seg_size(dev);
849 #ifdef CONFIG_HIGHMEM
850 const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
851 (unsigned long)buf < (PKMAP_BASE +
852 (LAST_PKMAP * PAGE_SIZE)));
853 #else
854 const bool kmap_buf = false;
855 #endif
856 int desc_len;
857 int sgs;
858 struct page *vm_page;
859 struct scatterlist *sg;
860 void *sg_buf;
861 size_t min;
862 int i, ret;
863
864 if (vmalloced_buf || kmap_buf) {
865 desc_len = min_t(int, max_seg_size, PAGE_SIZE);
866 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
867 } else if (virt_addr_valid(buf)) {
868 desc_len = min_t(int, max_seg_size, ctlr->max_dma_len);
869 sgs = DIV_ROUND_UP(len, desc_len);
870 } else {
871 return -EINVAL;
872 }
873
874 ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
875 if (ret != 0)
876 return ret;
877
878 sg = &sgt->sgl[0];
879 for (i = 0; i < sgs; i++) {
880
881 if (vmalloced_buf || kmap_buf) {
882 /*
883 * Next scatterlist entry size is the minimum between
884 * the desc_len and the remaining buffer length that
885 * fits in a page.
886 */
887 min = min_t(size_t, desc_len,
888 min_t(size_t, len,
889 PAGE_SIZE - offset_in_page(buf)));
890 if (vmalloced_buf)
891 vm_page = vmalloc_to_page(buf);
892 else
893 vm_page = kmap_to_page(buf);
894 if (!vm_page) {
895 sg_free_table(sgt);
896 return -ENOMEM;
897 }
898 sg_set_page(sg, vm_page,
899 min, offset_in_page(buf));
900 } else {
901 min = min_t(size_t, len, desc_len);
902 sg_buf = buf;
903 sg_set_buf(sg, sg_buf, min);
904 }
905
906 buf += min;
907 len -= min;
908 sg = sg_next(sg);
909 }
910
911 ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
912 if (!ret)
913 ret = -ENOMEM;
914 if (ret < 0) {
915 sg_free_table(sgt);
916 return ret;
917 }
918
919 sgt->nents = ret;
920
921 return 0;
922 }
923
spi_unmap_buf(struct spi_controller * ctlr,struct device * dev,struct sg_table * sgt,enum dma_data_direction dir)924 void spi_unmap_buf(struct spi_controller *ctlr, struct device *dev,
925 struct sg_table *sgt, enum dma_data_direction dir)
926 {
927 if (sgt->orig_nents) {
928 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
929 sg_free_table(sgt);
930 }
931 }
932
__spi_map_msg(struct spi_controller * ctlr,struct spi_message * msg)933 static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
934 {
935 struct device *tx_dev, *rx_dev;
936 struct spi_transfer *xfer;
937 int ret;
938
939 if (!ctlr->can_dma)
940 return 0;
941
942 if (ctlr->dma_tx)
943 tx_dev = ctlr->dma_tx->device->dev;
944 else
945 tx_dev = ctlr->dev.parent;
946
947 if (ctlr->dma_rx)
948 rx_dev = ctlr->dma_rx->device->dev;
949 else
950 rx_dev = ctlr->dev.parent;
951
952 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
953 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
954 continue;
955
956 if (xfer->tx_buf != NULL) {
957 ret = spi_map_buf(ctlr, tx_dev, &xfer->tx_sg,
958 (void *)xfer->tx_buf, xfer->len,
959 DMA_TO_DEVICE);
960 if (ret != 0)
961 return ret;
962 }
963
964 if (xfer->rx_buf != NULL) {
965 ret = spi_map_buf(ctlr, rx_dev, &xfer->rx_sg,
966 xfer->rx_buf, xfer->len,
967 DMA_FROM_DEVICE);
968 if (ret != 0) {
969 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg,
970 DMA_TO_DEVICE);
971 return ret;
972 }
973 }
974 }
975
976 ctlr->cur_msg_mapped = true;
977
978 return 0;
979 }
980
__spi_unmap_msg(struct spi_controller * ctlr,struct spi_message * msg)981 static int __spi_unmap_msg(struct spi_controller *ctlr, struct spi_message *msg)
982 {
983 struct spi_transfer *xfer;
984 struct device *tx_dev, *rx_dev;
985
986 if (!ctlr->cur_msg_mapped || !ctlr->can_dma)
987 return 0;
988
989 if (ctlr->dma_tx)
990 tx_dev = ctlr->dma_tx->device->dev;
991 else
992 tx_dev = ctlr->dev.parent;
993
994 if (ctlr->dma_rx)
995 rx_dev = ctlr->dma_rx->device->dev;
996 else
997 rx_dev = ctlr->dev.parent;
998
999 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1000 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
1001 continue;
1002
1003 spi_unmap_buf(ctlr, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
1004 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
1005 }
1006
1007 ctlr->cur_msg_mapped = false;
1008
1009 return 0;
1010 }
1011 #else /* !CONFIG_HAS_DMA */
__spi_map_msg(struct spi_controller * ctlr,struct spi_message * msg)1012 static inline int __spi_map_msg(struct spi_controller *ctlr,
1013 struct spi_message *msg)
1014 {
1015 return 0;
1016 }
1017
__spi_unmap_msg(struct spi_controller * ctlr,struct spi_message * msg)1018 static inline int __spi_unmap_msg(struct spi_controller *ctlr,
1019 struct spi_message *msg)
1020 {
1021 return 0;
1022 }
1023 #endif /* !CONFIG_HAS_DMA */
1024
spi_unmap_msg(struct spi_controller * ctlr,struct spi_message * msg)1025 static inline int spi_unmap_msg(struct spi_controller *ctlr,
1026 struct spi_message *msg)
1027 {
1028 struct spi_transfer *xfer;
1029
1030 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1031 /*
1032 * Restore the original value of tx_buf or rx_buf if they are
1033 * NULL.
1034 */
1035 if (xfer->tx_buf == ctlr->dummy_tx)
1036 xfer->tx_buf = NULL;
1037 if (xfer->rx_buf == ctlr->dummy_rx)
1038 xfer->rx_buf = NULL;
1039 }
1040
1041 return __spi_unmap_msg(ctlr, msg);
1042 }
1043
spi_map_msg(struct spi_controller * ctlr,struct spi_message * msg)1044 static int spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
1045 {
1046 struct spi_transfer *xfer;
1047 void *tmp;
1048 unsigned int max_tx, max_rx;
1049
1050 if ((ctlr->flags & (SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX))
1051 && !(msg->spi->mode & SPI_3WIRE)) {
1052 max_tx = 0;
1053 max_rx = 0;
1054
1055 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1056 if ((ctlr->flags & SPI_CONTROLLER_MUST_TX) &&
1057 !xfer->tx_buf)
1058 max_tx = max(xfer->len, max_tx);
1059 if ((ctlr->flags & SPI_CONTROLLER_MUST_RX) &&
1060 !xfer->rx_buf)
1061 max_rx = max(xfer->len, max_rx);
1062 }
1063
1064 if (max_tx) {
1065 tmp = krealloc(ctlr->dummy_tx, max_tx,
1066 GFP_KERNEL | GFP_DMA);
1067 if (!tmp)
1068 return -ENOMEM;
1069 ctlr->dummy_tx = tmp;
1070 memset(tmp, 0, max_tx);
1071 }
1072
1073 if (max_rx) {
1074 tmp = krealloc(ctlr->dummy_rx, max_rx,
1075 GFP_KERNEL | GFP_DMA);
1076 if (!tmp)
1077 return -ENOMEM;
1078 ctlr->dummy_rx = tmp;
1079 }
1080
1081 if (max_tx || max_rx) {
1082 list_for_each_entry(xfer, &msg->transfers,
1083 transfer_list) {
1084 if (!xfer->len)
1085 continue;
1086 if (!xfer->tx_buf)
1087 xfer->tx_buf = ctlr->dummy_tx;
1088 if (!xfer->rx_buf)
1089 xfer->rx_buf = ctlr->dummy_rx;
1090 }
1091 }
1092 }
1093
1094 return __spi_map_msg(ctlr, msg);
1095 }
1096
spi_transfer_wait(struct spi_controller * ctlr,struct spi_message * msg,struct spi_transfer * xfer)1097 static int spi_transfer_wait(struct spi_controller *ctlr,
1098 struct spi_message *msg,
1099 struct spi_transfer *xfer)
1100 {
1101 struct spi_statistics *statm = &ctlr->statistics;
1102 struct spi_statistics *stats = &msg->spi->statistics;
1103 u32 speed_hz = xfer->speed_hz;
1104 unsigned long long ms;
1105
1106 if (spi_controller_is_slave(ctlr)) {
1107 if (wait_for_completion_interruptible(&ctlr->xfer_completion)) {
1108 dev_dbg(&msg->spi->dev, "SPI transfer interrupted\n");
1109 return -EINTR;
1110 }
1111 } else {
1112 if (!speed_hz)
1113 speed_hz = 100000;
1114
1115 ms = 8LL * 1000LL * xfer->len;
1116 do_div(ms, speed_hz);
1117 ms += ms + 200; /* some tolerance */
1118
1119 if (ms > UINT_MAX)
1120 ms = UINT_MAX;
1121
1122 ms = wait_for_completion_timeout(&ctlr->xfer_completion,
1123 msecs_to_jiffies(ms));
1124
1125 if (ms == 0) {
1126 SPI_STATISTICS_INCREMENT_FIELD(statm, timedout);
1127 SPI_STATISTICS_INCREMENT_FIELD(stats, timedout);
1128 dev_err(&msg->spi->dev,
1129 "SPI transfer timed out\n");
1130 return -ETIMEDOUT;
1131 }
1132 }
1133
1134 return 0;
1135 }
1136
_spi_transfer_delay_ns(u32 ns)1137 static void _spi_transfer_delay_ns(u32 ns)
1138 {
1139 if (!ns)
1140 return;
1141 if (ns <= 1000) {
1142 ndelay(ns);
1143 } else {
1144 u32 us = DIV_ROUND_UP(ns, 1000);
1145
1146 if (us <= 10)
1147 udelay(us);
1148 else
1149 usleep_range(us, us + DIV_ROUND_UP(us, 10));
1150 }
1151 }
1152
spi_delay_to_ns(struct spi_delay * _delay,struct spi_transfer * xfer)1153 int spi_delay_to_ns(struct spi_delay *_delay, struct spi_transfer *xfer)
1154 {
1155 u32 delay = _delay->value;
1156 u32 unit = _delay->unit;
1157 u32 hz;
1158
1159 if (!delay)
1160 return 0;
1161
1162 switch (unit) {
1163 case SPI_DELAY_UNIT_USECS:
1164 delay *= 1000;
1165 break;
1166 case SPI_DELAY_UNIT_NSECS: /* nothing to do here */
1167 break;
1168 case SPI_DELAY_UNIT_SCK:
1169 /* clock cycles need to be obtained from spi_transfer */
1170 if (!xfer)
1171 return -EINVAL;
1172 /* if there is no effective speed know, then approximate
1173 * by underestimating with half the requested hz
1174 */
1175 hz = xfer->effective_speed_hz ?: xfer->speed_hz / 2;
1176 if (!hz)
1177 return -EINVAL;
1178 delay *= DIV_ROUND_UP(1000000000, hz);
1179 break;
1180 default:
1181 return -EINVAL;
1182 }
1183
1184 return delay;
1185 }
1186 EXPORT_SYMBOL_GPL(spi_delay_to_ns);
1187
spi_delay_exec(struct spi_delay * _delay,struct spi_transfer * xfer)1188 int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer)
1189 {
1190 int delay;
1191
1192 might_sleep();
1193
1194 if (!_delay)
1195 return -EINVAL;
1196
1197 delay = spi_delay_to_ns(_delay, xfer);
1198 if (delay < 0)
1199 return delay;
1200
1201 _spi_transfer_delay_ns(delay);
1202
1203 return 0;
1204 }
1205 EXPORT_SYMBOL_GPL(spi_delay_exec);
1206
_spi_transfer_cs_change_delay(struct spi_message * msg,struct spi_transfer * xfer)1207 static void _spi_transfer_cs_change_delay(struct spi_message *msg,
1208 struct spi_transfer *xfer)
1209 {
1210 u32 delay = xfer->cs_change_delay.value;
1211 u32 unit = xfer->cs_change_delay.unit;
1212 int ret;
1213
1214 /* return early on "fast" mode - for everything but USECS */
1215 if (!delay) {
1216 if (unit == SPI_DELAY_UNIT_USECS)
1217 _spi_transfer_delay_ns(10000);
1218 return;
1219 }
1220
1221 ret = spi_delay_exec(&xfer->cs_change_delay, xfer);
1222 if (ret) {
1223 dev_err_once(&msg->spi->dev,
1224 "Use of unsupported delay unit %i, using default of 10us\n",
1225 unit);
1226 _spi_transfer_delay_ns(10000);
1227 }
1228 }
1229
1230 /*
1231 * spi_transfer_one_message - Default implementation of transfer_one_message()
1232 *
1233 * This is a standard implementation of transfer_one_message() for
1234 * drivers which implement a transfer_one() operation. It provides
1235 * standard handling of delays and chip select management.
1236 */
spi_transfer_one_message(struct spi_controller * ctlr,struct spi_message * msg)1237 static int spi_transfer_one_message(struct spi_controller *ctlr,
1238 struct spi_message *msg)
1239 {
1240 struct spi_transfer *xfer;
1241 bool keep_cs = false;
1242 int ret = 0;
1243 struct spi_statistics *statm = &ctlr->statistics;
1244 struct spi_statistics *stats = &msg->spi->statistics;
1245
1246 spi_set_cs(msg->spi, true, false);
1247
1248 SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
1249 SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
1250
1251 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1252 trace_spi_transfer_start(msg, xfer);
1253
1254 spi_statistics_add_transfer_stats(statm, xfer, ctlr);
1255 spi_statistics_add_transfer_stats(stats, xfer, ctlr);
1256
1257 if (!ctlr->ptp_sts_supported) {
1258 xfer->ptp_sts_word_pre = 0;
1259 ptp_read_system_prets(xfer->ptp_sts);
1260 }
1261
1262 if ((xfer->tx_buf || xfer->rx_buf) && xfer->len) {
1263 reinit_completion(&ctlr->xfer_completion);
1264
1265 fallback_pio:
1266 ret = ctlr->transfer_one(ctlr, msg->spi, xfer);
1267 if (ret < 0) {
1268 if (ctlr->cur_msg_mapped &&
1269 (xfer->error & SPI_TRANS_FAIL_NO_START)) {
1270 __spi_unmap_msg(ctlr, msg);
1271 ctlr->fallback = true;
1272 xfer->error &= ~SPI_TRANS_FAIL_NO_START;
1273 goto fallback_pio;
1274 }
1275
1276 SPI_STATISTICS_INCREMENT_FIELD(statm,
1277 errors);
1278 SPI_STATISTICS_INCREMENT_FIELD(stats,
1279 errors);
1280 dev_err(&msg->spi->dev,
1281 "SPI transfer failed: %d\n", ret);
1282 goto out;
1283 }
1284
1285 if (ret > 0) {
1286 ret = spi_transfer_wait(ctlr, msg, xfer);
1287 if (ret < 0)
1288 msg->status = ret;
1289 }
1290 } else {
1291 if (xfer->len)
1292 dev_err(&msg->spi->dev,
1293 "Bufferless transfer has length %u\n",
1294 xfer->len);
1295 }
1296
1297 if (!ctlr->ptp_sts_supported) {
1298 ptp_read_system_postts(xfer->ptp_sts);
1299 xfer->ptp_sts_word_post = xfer->len;
1300 }
1301
1302 trace_spi_transfer_stop(msg, xfer);
1303
1304 if (msg->status != -EINPROGRESS)
1305 goto out;
1306
1307 spi_transfer_delay_exec(xfer);
1308
1309 if (xfer->cs_change) {
1310 if (list_is_last(&xfer->transfer_list,
1311 &msg->transfers)) {
1312 keep_cs = true;
1313 } else {
1314 spi_set_cs(msg->spi, false, false);
1315 _spi_transfer_cs_change_delay(msg, xfer);
1316 spi_set_cs(msg->spi, true, false);
1317 }
1318 }
1319
1320 msg->actual_length += xfer->len;
1321 }
1322
1323 out:
1324 if (ret != 0 || !keep_cs)
1325 spi_set_cs(msg->spi, false, false);
1326
1327 if (msg->status == -EINPROGRESS)
1328 msg->status = ret;
1329
1330 if (msg->status && ctlr->handle_err)
1331 ctlr->handle_err(ctlr, msg);
1332
1333 spi_finalize_current_message(ctlr);
1334
1335 return ret;
1336 }
1337
1338 /**
1339 * spi_finalize_current_transfer - report completion of a transfer
1340 * @ctlr: the controller reporting completion
1341 *
1342 * Called by SPI drivers using the core transfer_one_message()
1343 * implementation to notify it that the current interrupt driven
1344 * transfer has finished and the next one may be scheduled.
1345 */
spi_finalize_current_transfer(struct spi_controller * ctlr)1346 void spi_finalize_current_transfer(struct spi_controller *ctlr)
1347 {
1348 complete(&ctlr->xfer_completion);
1349 }
1350 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1351
spi_idle_runtime_pm(struct spi_controller * ctlr)1352 static void spi_idle_runtime_pm(struct spi_controller *ctlr)
1353 {
1354 if (ctlr->auto_runtime_pm) {
1355 pm_runtime_mark_last_busy(ctlr->dev.parent);
1356 pm_runtime_put_autosuspend(ctlr->dev.parent);
1357 }
1358 }
1359
1360 /**
1361 * __spi_pump_messages - function which processes spi message queue
1362 * @ctlr: controller to process queue for
1363 * @in_kthread: true if we are in the context of the message pump thread
1364 *
1365 * This function checks if there is any spi message in the queue that
1366 * needs processing and if so call out to the driver to initialize hardware
1367 * and transfer each message.
1368 *
1369 * Note that it is called both from the kthread itself and also from
1370 * inside spi_sync(); the queue extraction handling at the top of the
1371 * function should deal with this safely.
1372 */
__spi_pump_messages(struct spi_controller * ctlr,bool in_kthread)1373 static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
1374 {
1375 struct spi_transfer *xfer;
1376 struct spi_message *msg;
1377 bool was_busy = false;
1378 unsigned long flags;
1379 int ret;
1380
1381 /* Lock queue */
1382 spin_lock_irqsave(&ctlr->queue_lock, flags);
1383
1384 /* Make sure we are not already running a message */
1385 if (ctlr->cur_msg) {
1386 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1387 return;
1388 }
1389
1390 /* If another context is idling the device then defer */
1391 if (ctlr->idling) {
1392 kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1393 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1394 return;
1395 }
1396
1397 /* Check if the queue is idle */
1398 if (list_empty(&ctlr->queue) || !ctlr->running) {
1399 if (!ctlr->busy) {
1400 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1401 return;
1402 }
1403
1404 /* Defer any non-atomic teardown to the thread */
1405 if (!in_kthread) {
1406 if (!ctlr->dummy_rx && !ctlr->dummy_tx &&
1407 !ctlr->unprepare_transfer_hardware) {
1408 spi_idle_runtime_pm(ctlr);
1409 ctlr->busy = false;
1410 trace_spi_controller_idle(ctlr);
1411 } else {
1412 kthread_queue_work(ctlr->kworker,
1413 &ctlr->pump_messages);
1414 }
1415 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1416 return;
1417 }
1418
1419 ctlr->busy = false;
1420 ctlr->idling = true;
1421 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1422
1423 kfree(ctlr->dummy_rx);
1424 ctlr->dummy_rx = NULL;
1425 kfree(ctlr->dummy_tx);
1426 ctlr->dummy_tx = NULL;
1427 if (ctlr->unprepare_transfer_hardware &&
1428 ctlr->unprepare_transfer_hardware(ctlr))
1429 dev_err(&ctlr->dev,
1430 "failed to unprepare transfer hardware\n");
1431 spi_idle_runtime_pm(ctlr);
1432 trace_spi_controller_idle(ctlr);
1433
1434 spin_lock_irqsave(&ctlr->queue_lock, flags);
1435 ctlr->idling = false;
1436 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1437 return;
1438 }
1439
1440 /* Extract head of queue */
1441 msg = list_first_entry(&ctlr->queue, struct spi_message, queue);
1442 ctlr->cur_msg = msg;
1443
1444 list_del_init(&msg->queue);
1445 if (ctlr->busy)
1446 was_busy = true;
1447 else
1448 ctlr->busy = true;
1449 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1450
1451 mutex_lock(&ctlr->io_mutex);
1452
1453 if (!was_busy && ctlr->auto_runtime_pm) {
1454 ret = pm_runtime_get_sync(ctlr->dev.parent);
1455 if (ret < 0) {
1456 pm_runtime_put_noidle(ctlr->dev.parent);
1457 dev_err(&ctlr->dev, "Failed to power device: %d\n",
1458 ret);
1459 mutex_unlock(&ctlr->io_mutex);
1460 return;
1461 }
1462 }
1463
1464 if (!was_busy)
1465 trace_spi_controller_busy(ctlr);
1466
1467 if (!was_busy && ctlr->prepare_transfer_hardware) {
1468 ret = ctlr->prepare_transfer_hardware(ctlr);
1469 if (ret) {
1470 dev_err(&ctlr->dev,
1471 "failed to prepare transfer hardware: %d\n",
1472 ret);
1473
1474 if (ctlr->auto_runtime_pm)
1475 pm_runtime_put(ctlr->dev.parent);
1476
1477 msg->status = ret;
1478 spi_finalize_current_message(ctlr);
1479
1480 mutex_unlock(&ctlr->io_mutex);
1481 return;
1482 }
1483 }
1484
1485 trace_spi_message_start(msg);
1486
1487 if (ctlr->prepare_message) {
1488 ret = ctlr->prepare_message(ctlr, msg);
1489 if (ret) {
1490 dev_err(&ctlr->dev, "failed to prepare message: %d\n",
1491 ret);
1492 msg->status = ret;
1493 spi_finalize_current_message(ctlr);
1494 goto out;
1495 }
1496 ctlr->cur_msg_prepared = true;
1497 }
1498
1499 ret = spi_map_msg(ctlr, msg);
1500 if (ret) {
1501 msg->status = ret;
1502 spi_finalize_current_message(ctlr);
1503 goto out;
1504 }
1505
1506 if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
1507 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1508 xfer->ptp_sts_word_pre = 0;
1509 ptp_read_system_prets(xfer->ptp_sts);
1510 }
1511 }
1512
1513 ret = ctlr->transfer_one_message(ctlr, msg);
1514 if (ret) {
1515 dev_err(&ctlr->dev,
1516 "failed to transfer one message from queue\n");
1517 goto out;
1518 }
1519
1520 out:
1521 mutex_unlock(&ctlr->io_mutex);
1522
1523 /* Prod the scheduler in case transfer_one() was busy waiting */
1524 if (!ret)
1525 cond_resched();
1526 }
1527
1528 /**
1529 * spi_pump_messages - kthread work function which processes spi message queue
1530 * @work: pointer to kthread work struct contained in the controller struct
1531 */
spi_pump_messages(struct kthread_work * work)1532 static void spi_pump_messages(struct kthread_work *work)
1533 {
1534 struct spi_controller *ctlr =
1535 container_of(work, struct spi_controller, pump_messages);
1536
1537 __spi_pump_messages(ctlr, true);
1538 }
1539
1540 /**
1541 * spi_take_timestamp_pre - helper for drivers to collect the beginning of the
1542 * TX timestamp for the requested byte from the SPI
1543 * transfer. The frequency with which this function
1544 * must be called (once per word, once for the whole
1545 * transfer, once per batch of words etc) is arbitrary
1546 * as long as the @tx buffer offset is greater than or
1547 * equal to the requested byte at the time of the
1548 * call. The timestamp is only taken once, at the
1549 * first such call. It is assumed that the driver
1550 * advances its @tx buffer pointer monotonically.
1551 * @ctlr: Pointer to the spi_controller structure of the driver
1552 * @xfer: Pointer to the transfer being timestamped
1553 * @progress: How many words (not bytes) have been transferred so far
1554 * @irqs_off: If true, will disable IRQs and preemption for the duration of the
1555 * transfer, for less jitter in time measurement. Only compatible
1556 * with PIO drivers. If true, must follow up with
1557 * spi_take_timestamp_post or otherwise system will crash.
1558 * WARNING: for fully predictable results, the CPU frequency must
1559 * also be under control (governor).
1560 */
spi_take_timestamp_pre(struct spi_controller * ctlr,struct spi_transfer * xfer,size_t progress,bool irqs_off)1561 void spi_take_timestamp_pre(struct spi_controller *ctlr,
1562 struct spi_transfer *xfer,
1563 size_t progress, bool irqs_off)
1564 {
1565 if (!xfer->ptp_sts)
1566 return;
1567
1568 if (xfer->timestamped)
1569 return;
1570
1571 if (progress > xfer->ptp_sts_word_pre)
1572 return;
1573
1574 /* Capture the resolution of the timestamp */
1575 xfer->ptp_sts_word_pre = progress;
1576
1577 if (irqs_off) {
1578 local_irq_save(ctlr->irq_flags);
1579 preempt_disable();
1580 }
1581
1582 ptp_read_system_prets(xfer->ptp_sts);
1583 }
1584 EXPORT_SYMBOL_GPL(spi_take_timestamp_pre);
1585
1586 /**
1587 * spi_take_timestamp_post - helper for drivers to collect the end of the
1588 * TX timestamp for the requested byte from the SPI
1589 * transfer. Can be called with an arbitrary
1590 * frequency: only the first call where @tx exceeds
1591 * or is equal to the requested word will be
1592 * timestamped.
1593 * @ctlr: Pointer to the spi_controller structure of the driver
1594 * @xfer: Pointer to the transfer being timestamped
1595 * @progress: How many words (not bytes) have been transferred so far
1596 * @irqs_off: If true, will re-enable IRQs and preemption for the local CPU.
1597 */
spi_take_timestamp_post(struct spi_controller * ctlr,struct spi_transfer * xfer,size_t progress,bool irqs_off)1598 void spi_take_timestamp_post(struct spi_controller *ctlr,
1599 struct spi_transfer *xfer,
1600 size_t progress, bool irqs_off)
1601 {
1602 if (!xfer->ptp_sts)
1603 return;
1604
1605 if (xfer->timestamped)
1606 return;
1607
1608 if (progress < xfer->ptp_sts_word_post)
1609 return;
1610
1611 ptp_read_system_postts(xfer->ptp_sts);
1612
1613 if (irqs_off) {
1614 local_irq_restore(ctlr->irq_flags);
1615 preempt_enable();
1616 }
1617
1618 /* Capture the resolution of the timestamp */
1619 xfer->ptp_sts_word_post = progress;
1620
1621 xfer->timestamped = true;
1622 }
1623 EXPORT_SYMBOL_GPL(spi_take_timestamp_post);
1624
1625 /**
1626 * spi_set_thread_rt - set the controller to pump at realtime priority
1627 * @ctlr: controller to boost priority of
1628 *
1629 * This can be called because the controller requested realtime priority
1630 * (by setting the ->rt value before calling spi_register_controller()) or
1631 * because a device on the bus said that its transfers needed realtime
1632 * priority.
1633 *
1634 * NOTE: at the moment if any device on a bus says it needs realtime then
1635 * the thread will be at realtime priority for all transfers on that
1636 * controller. If this eventually becomes a problem we may see if we can
1637 * find a way to boost the priority only temporarily during relevant
1638 * transfers.
1639 */
spi_set_thread_rt(struct spi_controller * ctlr)1640 static void spi_set_thread_rt(struct spi_controller *ctlr)
1641 {
1642 dev_info(&ctlr->dev,
1643 "will run message pump with realtime priority\n");
1644 sched_set_fifo(ctlr->kworker->task);
1645 }
1646
spi_init_queue(struct spi_controller * ctlr)1647 static int spi_init_queue(struct spi_controller *ctlr)
1648 {
1649 ctlr->running = false;
1650 ctlr->busy = false;
1651
1652 ctlr->kworker = kthread_create_worker(0, dev_name(&ctlr->dev));
1653 if (IS_ERR(ctlr->kworker)) {
1654 dev_err(&ctlr->dev, "failed to create message pump kworker\n");
1655 return PTR_ERR(ctlr->kworker);
1656 }
1657
1658 kthread_init_work(&ctlr->pump_messages, spi_pump_messages);
1659
1660 /*
1661 * Controller config will indicate if this controller should run the
1662 * message pump with high (realtime) priority to reduce the transfer
1663 * latency on the bus by minimising the delay between a transfer
1664 * request and the scheduling of the message pump thread. Without this
1665 * setting the message pump thread will remain at default priority.
1666 */
1667 if (ctlr->rt)
1668 spi_set_thread_rt(ctlr);
1669
1670 return 0;
1671 }
1672
1673 /**
1674 * spi_get_next_queued_message() - called by driver to check for queued
1675 * messages
1676 * @ctlr: the controller to check for queued messages
1677 *
1678 * If there are more messages in the queue, the next message is returned from
1679 * this call.
1680 *
1681 * Return: the next message in the queue, else NULL if the queue is empty.
1682 */
spi_get_next_queued_message(struct spi_controller * ctlr)1683 struct spi_message *spi_get_next_queued_message(struct spi_controller *ctlr)
1684 {
1685 struct spi_message *next;
1686 unsigned long flags;
1687
1688 /* get a pointer to the next message, if any */
1689 spin_lock_irqsave(&ctlr->queue_lock, flags);
1690 next = list_first_entry_or_null(&ctlr->queue, struct spi_message,
1691 queue);
1692 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1693
1694 return next;
1695 }
1696 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1697
1698 /**
1699 * spi_finalize_current_message() - the current message is complete
1700 * @ctlr: the controller to return the message to
1701 *
1702 * Called by the driver to notify the core that the message in the front of the
1703 * queue is complete and can be removed from the queue.
1704 */
spi_finalize_current_message(struct spi_controller * ctlr)1705 void spi_finalize_current_message(struct spi_controller *ctlr)
1706 {
1707 struct spi_transfer *xfer;
1708 struct spi_message *mesg;
1709 unsigned long flags;
1710 int ret;
1711
1712 spin_lock_irqsave(&ctlr->queue_lock, flags);
1713 mesg = ctlr->cur_msg;
1714 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1715
1716 if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
1717 list_for_each_entry(xfer, &mesg->transfers, transfer_list) {
1718 ptp_read_system_postts(xfer->ptp_sts);
1719 xfer->ptp_sts_word_post = xfer->len;
1720 }
1721 }
1722
1723 if (unlikely(ctlr->ptp_sts_supported))
1724 list_for_each_entry(xfer, &mesg->transfers, transfer_list)
1725 WARN_ON_ONCE(xfer->ptp_sts && !xfer->timestamped);
1726
1727 spi_unmap_msg(ctlr, mesg);
1728
1729 /* In the prepare_messages callback the spi bus has the opportunity to
1730 * split a transfer to smaller chunks.
1731 * Release splited transfers here since spi_map_msg is done on the
1732 * splited transfers.
1733 */
1734 spi_res_release(ctlr, mesg);
1735
1736 if (ctlr->cur_msg_prepared && ctlr->unprepare_message) {
1737 ret = ctlr->unprepare_message(ctlr, mesg);
1738 if (ret) {
1739 dev_err(&ctlr->dev, "failed to unprepare message: %d\n",
1740 ret);
1741 }
1742 }
1743
1744 spin_lock_irqsave(&ctlr->queue_lock, flags);
1745 ctlr->cur_msg = NULL;
1746 ctlr->cur_msg_prepared = false;
1747 ctlr->fallback = false;
1748 kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1749 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1750
1751 trace_spi_message_done(mesg);
1752
1753 mesg->state = NULL;
1754 if (mesg->complete)
1755 mesg->complete(mesg->context);
1756 }
1757 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1758
spi_start_queue(struct spi_controller * ctlr)1759 static int spi_start_queue(struct spi_controller *ctlr)
1760 {
1761 unsigned long flags;
1762
1763 spin_lock_irqsave(&ctlr->queue_lock, flags);
1764
1765 if (ctlr->running || ctlr->busy) {
1766 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1767 return -EBUSY;
1768 }
1769
1770 ctlr->running = true;
1771 ctlr->cur_msg = NULL;
1772 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1773
1774 kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1775
1776 return 0;
1777 }
1778
spi_stop_queue(struct spi_controller * ctlr)1779 static int spi_stop_queue(struct spi_controller *ctlr)
1780 {
1781 unsigned long flags;
1782 unsigned limit = 500;
1783 int ret = 0;
1784
1785 spin_lock_irqsave(&ctlr->queue_lock, flags);
1786
1787 /*
1788 * This is a bit lame, but is optimized for the common execution path.
1789 * A wait_queue on the ctlr->busy could be used, but then the common
1790 * execution path (pump_messages) would be required to call wake_up or
1791 * friends on every SPI message. Do this instead.
1792 */
1793 while ((!list_empty(&ctlr->queue) || ctlr->busy) && limit--) {
1794 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1795 usleep_range(10000, 11000);
1796 spin_lock_irqsave(&ctlr->queue_lock, flags);
1797 }
1798
1799 if (!list_empty(&ctlr->queue) || ctlr->busy)
1800 ret = -EBUSY;
1801 else
1802 ctlr->running = false;
1803
1804 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1805
1806 if (ret) {
1807 dev_warn(&ctlr->dev, "could not stop message queue\n");
1808 return ret;
1809 }
1810 return ret;
1811 }
1812
spi_destroy_queue(struct spi_controller * ctlr)1813 static int spi_destroy_queue(struct spi_controller *ctlr)
1814 {
1815 int ret;
1816
1817 ret = spi_stop_queue(ctlr);
1818
1819 /*
1820 * kthread_flush_worker will block until all work is done.
1821 * If the reason that stop_queue timed out is that the work will never
1822 * finish, then it does no good to call flush/stop thread, so
1823 * return anyway.
1824 */
1825 if (ret) {
1826 dev_err(&ctlr->dev, "problem destroying queue\n");
1827 return ret;
1828 }
1829
1830 kthread_destroy_worker(ctlr->kworker);
1831
1832 return 0;
1833 }
1834
__spi_queued_transfer(struct spi_device * spi,struct spi_message * msg,bool need_pump)1835 static int __spi_queued_transfer(struct spi_device *spi,
1836 struct spi_message *msg,
1837 bool need_pump)
1838 {
1839 struct spi_controller *ctlr = spi->controller;
1840 unsigned long flags;
1841
1842 spin_lock_irqsave(&ctlr->queue_lock, flags);
1843
1844 if (!ctlr->running) {
1845 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1846 return -ESHUTDOWN;
1847 }
1848 msg->actual_length = 0;
1849 msg->status = -EINPROGRESS;
1850
1851 list_add_tail(&msg->queue, &ctlr->queue);
1852 if (!ctlr->busy && need_pump)
1853 kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1854
1855 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1856 return 0;
1857 }
1858
1859 /**
1860 * spi_queued_transfer - transfer function for queued transfers
1861 * @spi: spi device which is requesting transfer
1862 * @msg: spi message which is to handled is queued to driver queue
1863 *
1864 * Return: zero on success, else a negative error code.
1865 */
spi_queued_transfer(struct spi_device * spi,struct spi_message * msg)1866 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1867 {
1868 return __spi_queued_transfer(spi, msg, true);
1869 }
1870
spi_controller_initialize_queue(struct spi_controller * ctlr)1871 static int spi_controller_initialize_queue(struct spi_controller *ctlr)
1872 {
1873 int ret;
1874
1875 ctlr->transfer = spi_queued_transfer;
1876 if (!ctlr->transfer_one_message)
1877 ctlr->transfer_one_message = spi_transfer_one_message;
1878
1879 /* Initialize and start queue */
1880 ret = spi_init_queue(ctlr);
1881 if (ret) {
1882 dev_err(&ctlr->dev, "problem initializing queue\n");
1883 goto err_init_queue;
1884 }
1885 ctlr->queued = true;
1886 ret = spi_start_queue(ctlr);
1887 if (ret) {
1888 dev_err(&ctlr->dev, "problem starting queue\n");
1889 goto err_start_queue;
1890 }
1891
1892 return 0;
1893
1894 err_start_queue:
1895 spi_destroy_queue(ctlr);
1896 err_init_queue:
1897 return ret;
1898 }
1899
1900 /**
1901 * spi_flush_queue - Send all pending messages in the queue from the callers'
1902 * context
1903 * @ctlr: controller to process queue for
1904 *
1905 * This should be used when one wants to ensure all pending messages have been
1906 * sent before doing something. Is used by the spi-mem code to make sure SPI
1907 * memory operations do not preempt regular SPI transfers that have been queued
1908 * before the spi-mem operation.
1909 */
spi_flush_queue(struct spi_controller * ctlr)1910 void spi_flush_queue(struct spi_controller *ctlr)
1911 {
1912 if (ctlr->transfer == spi_queued_transfer)
1913 __spi_pump_messages(ctlr, false);
1914 }
1915
1916 /*-------------------------------------------------------------------------*/
1917
1918 #if defined(CONFIG_OF)
of_spi_parse_dt(struct spi_controller * ctlr,struct spi_device * spi,struct device_node * nc)1919 static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
1920 struct device_node *nc)
1921 {
1922 u32 value;
1923 int rc;
1924
1925 /* Mode (clock phase/polarity/etc.) */
1926 if (of_property_read_bool(nc, "spi-cpha"))
1927 spi->mode |= SPI_CPHA;
1928 if (of_property_read_bool(nc, "spi-cpol"))
1929 spi->mode |= SPI_CPOL;
1930 if (of_property_read_bool(nc, "spi-3wire"))
1931 spi->mode |= SPI_3WIRE;
1932 if (of_property_read_bool(nc, "spi-lsb-first"))
1933 spi->mode |= SPI_LSB_FIRST;
1934 if (of_property_read_bool(nc, "spi-cs-high"))
1935 spi->mode |= SPI_CS_HIGH;
1936
1937 /* Device DUAL/QUAD mode */
1938 if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1939 switch (value) {
1940 case 0:
1941 spi->mode |= SPI_NO_TX;
1942 break;
1943 case 1:
1944 break;
1945 case 2:
1946 spi->mode |= SPI_TX_DUAL;
1947 break;
1948 case 4:
1949 spi->mode |= SPI_TX_QUAD;
1950 break;
1951 case 8:
1952 spi->mode |= SPI_TX_OCTAL;
1953 break;
1954 default:
1955 dev_warn(&ctlr->dev,
1956 "spi-tx-bus-width %d not supported\n",
1957 value);
1958 break;
1959 }
1960 }
1961
1962 if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1963 switch (value) {
1964 case 0:
1965 spi->mode |= SPI_NO_RX;
1966 break;
1967 case 1:
1968 break;
1969 case 2:
1970 spi->mode |= SPI_RX_DUAL;
1971 break;
1972 case 4:
1973 spi->mode |= SPI_RX_QUAD;
1974 break;
1975 case 8:
1976 spi->mode |= SPI_RX_OCTAL;
1977 break;
1978 default:
1979 dev_warn(&ctlr->dev,
1980 "spi-rx-bus-width %d not supported\n",
1981 value);
1982 break;
1983 }
1984 }
1985
1986 if (spi_controller_is_slave(ctlr)) {
1987 if (!of_node_name_eq(nc, "slave")) {
1988 dev_err(&ctlr->dev, "%pOF is not called 'slave'\n",
1989 nc);
1990 return -EINVAL;
1991 }
1992 return 0;
1993 }
1994
1995 /* Device address */
1996 rc = of_property_read_u32(nc, "reg", &value);
1997 if (rc) {
1998 dev_err(&ctlr->dev, "%pOF has no valid 'reg' property (%d)\n",
1999 nc, rc);
2000 return rc;
2001 }
2002 spi->chip_select = value;
2003
2004 /* Device speed */
2005 if (!of_property_read_u32(nc, "spi-max-frequency", &value))
2006 spi->max_speed_hz = value;
2007
2008 return 0;
2009 }
2010
2011 static struct spi_device *
of_register_spi_device(struct spi_controller * ctlr,struct device_node * nc)2012 of_register_spi_device(struct spi_controller *ctlr, struct device_node *nc)
2013 {
2014 struct spi_device *spi;
2015 int rc;
2016
2017 /* Alloc an spi_device */
2018 spi = spi_alloc_device(ctlr);
2019 if (!spi) {
2020 dev_err(&ctlr->dev, "spi_device alloc error for %pOF\n", nc);
2021 rc = -ENOMEM;
2022 goto err_out;
2023 }
2024
2025 /* Select device driver */
2026 rc = of_modalias_node(nc, spi->modalias,
2027 sizeof(spi->modalias));
2028 if (rc < 0) {
2029 dev_err(&ctlr->dev, "cannot find modalias for %pOF\n", nc);
2030 goto err_out;
2031 }
2032
2033 rc = of_spi_parse_dt(ctlr, spi, nc);
2034 if (rc)
2035 goto err_out;
2036
2037 /* Store a pointer to the node in the device structure */
2038 of_node_get(nc);
2039 spi->dev.of_node = nc;
2040
2041 /* Register the new device */
2042 rc = spi_add_device(spi);
2043 if (rc) {
2044 dev_err(&ctlr->dev, "spi_device register error %pOF\n", nc);
2045 goto err_of_node_put;
2046 }
2047
2048 return spi;
2049
2050 err_of_node_put:
2051 of_node_put(nc);
2052 err_out:
2053 spi_dev_put(spi);
2054 return ERR_PTR(rc);
2055 }
2056
2057 /**
2058 * of_register_spi_devices() - Register child devices onto the SPI bus
2059 * @ctlr: Pointer to spi_controller device
2060 *
2061 * Registers an spi_device for each child node of controller node which
2062 * represents a valid SPI slave.
2063 */
of_register_spi_devices(struct spi_controller * ctlr)2064 static void of_register_spi_devices(struct spi_controller *ctlr)
2065 {
2066 struct spi_device *spi;
2067 struct device_node *nc;
2068
2069 if (!ctlr->dev.of_node)
2070 return;
2071
2072 for_each_available_child_of_node(ctlr->dev.of_node, nc) {
2073 if (of_node_test_and_set_flag(nc, OF_POPULATED))
2074 continue;
2075 spi = of_register_spi_device(ctlr, nc);
2076 if (IS_ERR(spi)) {
2077 dev_warn(&ctlr->dev,
2078 "Failed to create SPI device for %pOF\n", nc);
2079 of_node_clear_flag(nc, OF_POPULATED);
2080 }
2081 }
2082 }
2083 #else
of_register_spi_devices(struct spi_controller * ctlr)2084 static void of_register_spi_devices(struct spi_controller *ctlr) { }
2085 #endif
2086
2087 #ifdef CONFIG_ACPI
2088 struct acpi_spi_lookup {
2089 struct spi_controller *ctlr;
2090 u32 max_speed_hz;
2091 u32 mode;
2092 int irq;
2093 u8 bits_per_word;
2094 u8 chip_select;
2095 };
2096
acpi_spi_parse_apple_properties(struct acpi_device * dev,struct acpi_spi_lookup * lookup)2097 static void acpi_spi_parse_apple_properties(struct acpi_device *dev,
2098 struct acpi_spi_lookup *lookup)
2099 {
2100 const union acpi_object *obj;
2101
2102 if (!x86_apple_machine)
2103 return;
2104
2105 if (!acpi_dev_get_property(dev, "spiSclkPeriod", ACPI_TYPE_BUFFER, &obj)
2106 && obj->buffer.length >= 4)
2107 lookup->max_speed_hz = NSEC_PER_SEC / *(u32 *)obj->buffer.pointer;
2108
2109 if (!acpi_dev_get_property(dev, "spiWordSize", ACPI_TYPE_BUFFER, &obj)
2110 && obj->buffer.length == 8)
2111 lookup->bits_per_word = *(u64 *)obj->buffer.pointer;
2112
2113 if (!acpi_dev_get_property(dev, "spiBitOrder", ACPI_TYPE_BUFFER, &obj)
2114 && obj->buffer.length == 8 && !*(u64 *)obj->buffer.pointer)
2115 lookup->mode |= SPI_LSB_FIRST;
2116
2117 if (!acpi_dev_get_property(dev, "spiSPO", ACPI_TYPE_BUFFER, &obj)
2118 && obj->buffer.length == 8 && *(u64 *)obj->buffer.pointer)
2119 lookup->mode |= SPI_CPOL;
2120
2121 if (!acpi_dev_get_property(dev, "spiSPH", ACPI_TYPE_BUFFER, &obj)
2122 && obj->buffer.length == 8 && *(u64 *)obj->buffer.pointer)
2123 lookup->mode |= SPI_CPHA;
2124 }
2125
acpi_spi_add_resource(struct acpi_resource * ares,void * data)2126 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
2127 {
2128 struct acpi_spi_lookup *lookup = data;
2129 struct spi_controller *ctlr = lookup->ctlr;
2130
2131 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
2132 struct acpi_resource_spi_serialbus *sb;
2133 acpi_handle parent_handle;
2134 acpi_status status;
2135
2136 sb = &ares->data.spi_serial_bus;
2137 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
2138
2139 status = acpi_get_handle(NULL,
2140 sb->resource_source.string_ptr,
2141 &parent_handle);
2142
2143 if (ACPI_FAILURE(status) ||
2144 ACPI_HANDLE(ctlr->dev.parent) != parent_handle)
2145 return -ENODEV;
2146
2147 /*
2148 * ACPI DeviceSelection numbering is handled by the
2149 * host controller driver in Windows and can vary
2150 * from driver to driver. In Linux we always expect
2151 * 0 .. max - 1 so we need to ask the driver to
2152 * translate between the two schemes.
2153 */
2154 if (ctlr->fw_translate_cs) {
2155 int cs = ctlr->fw_translate_cs(ctlr,
2156 sb->device_selection);
2157 if (cs < 0)
2158 return cs;
2159 lookup->chip_select = cs;
2160 } else {
2161 lookup->chip_select = sb->device_selection;
2162 }
2163
2164 lookup->max_speed_hz = sb->connection_speed;
2165 lookup->bits_per_word = sb->data_bit_length;
2166
2167 if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
2168 lookup->mode |= SPI_CPHA;
2169 if (sb->clock_polarity == ACPI_SPI_START_HIGH)
2170 lookup->mode |= SPI_CPOL;
2171 if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
2172 lookup->mode |= SPI_CS_HIGH;
2173 }
2174 } else if (lookup->irq < 0) {
2175 struct resource r;
2176
2177 if (acpi_dev_resource_interrupt(ares, 0, &r))
2178 lookup->irq = r.start;
2179 }
2180
2181 /* Always tell the ACPI core to skip this resource */
2182 return 1;
2183 }
2184
acpi_register_spi_device(struct spi_controller * ctlr,struct acpi_device * adev)2185 static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
2186 struct acpi_device *adev)
2187 {
2188 acpi_handle parent_handle = NULL;
2189 struct list_head resource_list;
2190 struct acpi_spi_lookup lookup = {};
2191 struct spi_device *spi;
2192 int ret;
2193
2194 if (acpi_bus_get_status(adev) || !adev->status.present ||
2195 acpi_device_enumerated(adev))
2196 return AE_OK;
2197
2198 lookup.ctlr = ctlr;
2199 lookup.irq = -1;
2200
2201 INIT_LIST_HEAD(&resource_list);
2202 ret = acpi_dev_get_resources(adev, &resource_list,
2203 acpi_spi_add_resource, &lookup);
2204 acpi_dev_free_resource_list(&resource_list);
2205
2206 if (ret < 0)
2207 /* found SPI in _CRS but it points to another controller */
2208 return AE_OK;
2209
2210 if (!lookup.max_speed_hz &&
2211 ACPI_SUCCESS(acpi_get_parent(adev->handle, &parent_handle)) &&
2212 ACPI_HANDLE(ctlr->dev.parent) == parent_handle) {
2213 /* Apple does not use _CRS but nested devices for SPI slaves */
2214 acpi_spi_parse_apple_properties(adev, &lookup);
2215 }
2216
2217 if (!lookup.max_speed_hz)
2218 return AE_OK;
2219
2220 spi = spi_alloc_device(ctlr);
2221 if (!spi) {
2222 dev_err(&ctlr->dev, "failed to allocate SPI device for %s\n",
2223 dev_name(&adev->dev));
2224 return AE_NO_MEMORY;
2225 }
2226
2227
2228 ACPI_COMPANION_SET(&spi->dev, adev);
2229 spi->max_speed_hz = lookup.max_speed_hz;
2230 spi->mode |= lookup.mode;
2231 spi->irq = lookup.irq;
2232 spi->bits_per_word = lookup.bits_per_word;
2233 spi->chip_select = lookup.chip_select;
2234
2235 acpi_set_modalias(adev, acpi_device_hid(adev), spi->modalias,
2236 sizeof(spi->modalias));
2237
2238 if (spi->irq < 0)
2239 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
2240
2241 acpi_device_set_enumerated(adev);
2242
2243 adev->power.flags.ignore_parent = true;
2244 if (spi_add_device(spi)) {
2245 adev->power.flags.ignore_parent = false;
2246 dev_err(&ctlr->dev, "failed to add SPI device %s from ACPI\n",
2247 dev_name(&adev->dev));
2248 spi_dev_put(spi);
2249 }
2250
2251 return AE_OK;
2252 }
2253
acpi_spi_add_device(acpi_handle handle,u32 level,void * data,void ** return_value)2254 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
2255 void *data, void **return_value)
2256 {
2257 struct spi_controller *ctlr = data;
2258 struct acpi_device *adev;
2259
2260 if (acpi_bus_get_device(handle, &adev))
2261 return AE_OK;
2262
2263 return acpi_register_spi_device(ctlr, adev);
2264 }
2265
2266 #define SPI_ACPI_ENUMERATE_MAX_DEPTH 32
2267
acpi_register_spi_devices(struct spi_controller * ctlr)2268 static void acpi_register_spi_devices(struct spi_controller *ctlr)
2269 {
2270 acpi_status status;
2271 acpi_handle handle;
2272
2273 handle = ACPI_HANDLE(ctlr->dev.parent);
2274 if (!handle)
2275 return;
2276
2277 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
2278 SPI_ACPI_ENUMERATE_MAX_DEPTH,
2279 acpi_spi_add_device, NULL, ctlr, NULL);
2280 if (ACPI_FAILURE(status))
2281 dev_warn(&ctlr->dev, "failed to enumerate SPI slaves\n");
2282 }
2283 #else
acpi_register_spi_devices(struct spi_controller * ctlr)2284 static inline void acpi_register_spi_devices(struct spi_controller *ctlr) {}
2285 #endif /* CONFIG_ACPI */
2286
spi_controller_release(struct device * dev)2287 static void spi_controller_release(struct device *dev)
2288 {
2289 struct spi_controller *ctlr;
2290
2291 ctlr = container_of(dev, struct spi_controller, dev);
2292 kfree(ctlr);
2293 }
2294
2295 static struct class spi_master_class = {
2296 .name = "spi_master",
2297 .owner = THIS_MODULE,
2298 .dev_release = spi_controller_release,
2299 .dev_groups = spi_master_groups,
2300 };
2301
2302 #ifdef CONFIG_SPI_SLAVE
2303 /**
2304 * spi_slave_abort - abort the ongoing transfer request on an SPI slave
2305 * controller
2306 * @spi: device used for the current transfer
2307 */
spi_slave_abort(struct spi_device * spi)2308 int spi_slave_abort(struct spi_device *spi)
2309 {
2310 struct spi_controller *ctlr = spi->controller;
2311
2312 if (spi_controller_is_slave(ctlr) && ctlr->slave_abort)
2313 return ctlr->slave_abort(ctlr);
2314
2315 return -ENOTSUPP;
2316 }
2317 EXPORT_SYMBOL_GPL(spi_slave_abort);
2318
match_true(struct device * dev,void * data)2319 static int match_true(struct device *dev, void *data)
2320 {
2321 return 1;
2322 }
2323
slave_show(struct device * dev,struct device_attribute * attr,char * buf)2324 static ssize_t slave_show(struct device *dev, struct device_attribute *attr,
2325 char *buf)
2326 {
2327 struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2328 dev);
2329 struct device *child;
2330
2331 child = device_find_child(&ctlr->dev, NULL, match_true);
2332 return sprintf(buf, "%s\n",
2333 child ? to_spi_device(child)->modalias : NULL);
2334 }
2335
slave_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)2336 static ssize_t slave_store(struct device *dev, struct device_attribute *attr,
2337 const char *buf, size_t count)
2338 {
2339 struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2340 dev);
2341 struct spi_device *spi;
2342 struct device *child;
2343 char name[32];
2344 int rc;
2345
2346 rc = sscanf(buf, "%31s", name);
2347 if (rc != 1 || !name[0])
2348 return -EINVAL;
2349
2350 child = device_find_child(&ctlr->dev, NULL, match_true);
2351 if (child) {
2352 /* Remove registered slave */
2353 device_unregister(child);
2354 put_device(child);
2355 }
2356
2357 if (strcmp(name, "(null)")) {
2358 /* Register new slave */
2359 spi = spi_alloc_device(ctlr);
2360 if (!spi)
2361 return -ENOMEM;
2362
2363 strlcpy(spi->modalias, name, sizeof(spi->modalias));
2364
2365 rc = spi_add_device(spi);
2366 if (rc) {
2367 spi_dev_put(spi);
2368 return rc;
2369 }
2370 }
2371
2372 return count;
2373 }
2374
2375 static DEVICE_ATTR_RW(slave);
2376
2377 static struct attribute *spi_slave_attrs[] = {
2378 &dev_attr_slave.attr,
2379 NULL,
2380 };
2381
2382 static const struct attribute_group spi_slave_group = {
2383 .attrs = spi_slave_attrs,
2384 };
2385
2386 static const struct attribute_group *spi_slave_groups[] = {
2387 &spi_controller_statistics_group,
2388 &spi_slave_group,
2389 NULL,
2390 };
2391
2392 static struct class spi_slave_class = {
2393 .name = "spi_slave",
2394 .owner = THIS_MODULE,
2395 .dev_release = spi_controller_release,
2396 .dev_groups = spi_slave_groups,
2397 };
2398 #else
2399 extern struct class spi_slave_class; /* dummy */
2400 #endif
2401
2402 /**
2403 * __spi_alloc_controller - allocate an SPI master or slave controller
2404 * @dev: the controller, possibly using the platform_bus
2405 * @size: how much zeroed driver-private data to allocate; the pointer to this
2406 * memory is in the driver_data field of the returned device, accessible
2407 * with spi_controller_get_devdata(); the memory is cacheline aligned;
2408 * drivers granting DMA access to portions of their private data need to
2409 * round up @size using ALIGN(size, dma_get_cache_alignment()).
2410 * @slave: flag indicating whether to allocate an SPI master (false) or SPI
2411 * slave (true) controller
2412 * Context: can sleep
2413 *
2414 * This call is used only by SPI controller drivers, which are the
2415 * only ones directly touching chip registers. It's how they allocate
2416 * an spi_controller structure, prior to calling spi_register_controller().
2417 *
2418 * This must be called from context that can sleep.
2419 *
2420 * The caller is responsible for assigning the bus number and initializing the
2421 * controller's methods before calling spi_register_controller(); and (after
2422 * errors adding the device) calling spi_controller_put() to prevent a memory
2423 * leak.
2424 *
2425 * Return: the SPI controller structure on success, else NULL.
2426 */
__spi_alloc_controller(struct device * dev,unsigned int size,bool slave)2427 struct spi_controller *__spi_alloc_controller(struct device *dev,
2428 unsigned int size, bool slave)
2429 {
2430 struct spi_controller *ctlr;
2431 size_t ctlr_size = ALIGN(sizeof(*ctlr), dma_get_cache_alignment());
2432
2433 if (!dev)
2434 return NULL;
2435
2436 ctlr = kzalloc(size + ctlr_size, GFP_KERNEL);
2437 if (!ctlr)
2438 return NULL;
2439
2440 device_initialize(&ctlr->dev);
2441 ctlr->bus_num = -1;
2442 ctlr->num_chipselect = 1;
2443 ctlr->slave = slave;
2444 if (IS_ENABLED(CONFIG_SPI_SLAVE) && slave)
2445 ctlr->dev.class = &spi_slave_class;
2446 else
2447 ctlr->dev.class = &spi_master_class;
2448 ctlr->dev.parent = dev;
2449 pm_suspend_ignore_children(&ctlr->dev, true);
2450 spi_controller_set_devdata(ctlr, (void *)ctlr + ctlr_size);
2451
2452 return ctlr;
2453 }
2454 EXPORT_SYMBOL_GPL(__spi_alloc_controller);
2455
devm_spi_release_controller(struct device * dev,void * ctlr)2456 static void devm_spi_release_controller(struct device *dev, void *ctlr)
2457 {
2458 spi_controller_put(*(struct spi_controller **)ctlr);
2459 }
2460
2461 /**
2462 * __devm_spi_alloc_controller - resource-managed __spi_alloc_controller()
2463 * @dev: physical device of SPI controller
2464 * @size: how much zeroed driver-private data to allocate
2465 * @slave: whether to allocate an SPI master (false) or SPI slave (true)
2466 * Context: can sleep
2467 *
2468 * Allocate an SPI controller and automatically release a reference on it
2469 * when @dev is unbound from its driver. Drivers are thus relieved from
2470 * having to call spi_controller_put().
2471 *
2472 * The arguments to this function are identical to __spi_alloc_controller().
2473 *
2474 * Return: the SPI controller structure on success, else NULL.
2475 */
__devm_spi_alloc_controller(struct device * dev,unsigned int size,bool slave)2476 struct spi_controller *__devm_spi_alloc_controller(struct device *dev,
2477 unsigned int size,
2478 bool slave)
2479 {
2480 struct spi_controller **ptr, *ctlr;
2481
2482 ptr = devres_alloc(devm_spi_release_controller, sizeof(*ptr),
2483 GFP_KERNEL);
2484 if (!ptr)
2485 return NULL;
2486
2487 ctlr = __spi_alloc_controller(dev, size, slave);
2488 if (ctlr) {
2489 ctlr->devm_allocated = true;
2490 *ptr = ctlr;
2491 devres_add(dev, ptr);
2492 } else {
2493 devres_free(ptr);
2494 }
2495
2496 return ctlr;
2497 }
2498 EXPORT_SYMBOL_GPL(__devm_spi_alloc_controller);
2499
2500 #ifdef CONFIG_OF
of_spi_get_gpio_numbers(struct spi_controller * ctlr)2501 static int of_spi_get_gpio_numbers(struct spi_controller *ctlr)
2502 {
2503 int nb, i, *cs;
2504 struct device_node *np = ctlr->dev.of_node;
2505
2506 if (!np)
2507 return 0;
2508
2509 nb = of_gpio_named_count(np, "cs-gpios");
2510 ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2511
2512 /* Return error only for an incorrectly formed cs-gpios property */
2513 if (nb == 0 || nb == -ENOENT)
2514 return 0;
2515 else if (nb < 0)
2516 return nb;
2517
2518 cs = devm_kcalloc(&ctlr->dev, ctlr->num_chipselect, sizeof(int),
2519 GFP_KERNEL);
2520 ctlr->cs_gpios = cs;
2521
2522 if (!ctlr->cs_gpios)
2523 return -ENOMEM;
2524
2525 for (i = 0; i < ctlr->num_chipselect; i++)
2526 cs[i] = -ENOENT;
2527
2528 for (i = 0; i < nb; i++)
2529 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
2530
2531 return 0;
2532 }
2533 #else
of_spi_get_gpio_numbers(struct spi_controller * ctlr)2534 static int of_spi_get_gpio_numbers(struct spi_controller *ctlr)
2535 {
2536 return 0;
2537 }
2538 #endif
2539
2540 /**
2541 * spi_get_gpio_descs() - grab chip select GPIOs for the master
2542 * @ctlr: The SPI master to grab GPIO descriptors for
2543 */
spi_get_gpio_descs(struct spi_controller * ctlr)2544 static int spi_get_gpio_descs(struct spi_controller *ctlr)
2545 {
2546 int nb, i;
2547 struct gpio_desc **cs;
2548 struct device *dev = &ctlr->dev;
2549 unsigned long native_cs_mask = 0;
2550 unsigned int num_cs_gpios = 0;
2551
2552 nb = gpiod_count(dev, "cs");
2553 if (nb < 0) {
2554 /* No GPIOs at all is fine, else return the error */
2555 if (nb == -ENOENT)
2556 return 0;
2557 return nb;
2558 }
2559
2560 ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2561
2562 cs = devm_kcalloc(dev, ctlr->num_chipselect, sizeof(*cs),
2563 GFP_KERNEL);
2564 if (!cs)
2565 return -ENOMEM;
2566 ctlr->cs_gpiods = cs;
2567
2568 for (i = 0; i < nb; i++) {
2569 /*
2570 * Most chipselects are active low, the inverted
2571 * semantics are handled by special quirks in gpiolib,
2572 * so initializing them GPIOD_OUT_LOW here means
2573 * "unasserted", in most cases this will drive the physical
2574 * line high.
2575 */
2576 cs[i] = devm_gpiod_get_index_optional(dev, "cs", i,
2577 GPIOD_OUT_LOW);
2578 if (IS_ERR(cs[i]))
2579 return PTR_ERR(cs[i]);
2580
2581 if (cs[i]) {
2582 /*
2583 * If we find a CS GPIO, name it after the device and
2584 * chip select line.
2585 */
2586 char *gpioname;
2587
2588 gpioname = devm_kasprintf(dev, GFP_KERNEL, "%s CS%d",
2589 dev_name(dev), i);
2590 if (!gpioname)
2591 return -ENOMEM;
2592 gpiod_set_consumer_name(cs[i], gpioname);
2593 num_cs_gpios++;
2594 continue;
2595 }
2596
2597 if (ctlr->max_native_cs && i >= ctlr->max_native_cs) {
2598 dev_err(dev, "Invalid native chip select %d\n", i);
2599 return -EINVAL;
2600 }
2601 native_cs_mask |= BIT(i);
2602 }
2603
2604 ctlr->unused_native_cs = ffz(native_cs_mask);
2605 if (num_cs_gpios && ctlr->max_native_cs &&
2606 ctlr->unused_native_cs >= ctlr->max_native_cs) {
2607 dev_err(dev, "No unused native chip select available\n");
2608 return -EINVAL;
2609 }
2610
2611 return 0;
2612 }
2613
spi_controller_check_ops(struct spi_controller * ctlr)2614 static int spi_controller_check_ops(struct spi_controller *ctlr)
2615 {
2616 /*
2617 * The controller may implement only the high-level SPI-memory like
2618 * operations if it does not support regular SPI transfers, and this is
2619 * valid use case.
2620 * If ->mem_ops is NULL, we request that at least one of the
2621 * ->transfer_xxx() method be implemented.
2622 */
2623 if (ctlr->mem_ops) {
2624 if (!ctlr->mem_ops->exec_op)
2625 return -EINVAL;
2626 } else if (!ctlr->transfer && !ctlr->transfer_one &&
2627 !ctlr->transfer_one_message) {
2628 return -EINVAL;
2629 }
2630
2631 return 0;
2632 }
2633
2634 /**
2635 * spi_register_controller - register SPI master or slave controller
2636 * @ctlr: initialized master, originally from spi_alloc_master() or
2637 * spi_alloc_slave()
2638 * Context: can sleep
2639 *
2640 * SPI controllers connect to their drivers using some non-SPI bus,
2641 * such as the platform bus. The final stage of probe() in that code
2642 * includes calling spi_register_controller() to hook up to this SPI bus glue.
2643 *
2644 * SPI controllers use board specific (often SOC specific) bus numbers,
2645 * and board-specific addressing for SPI devices combines those numbers
2646 * with chip select numbers. Since SPI does not directly support dynamic
2647 * device identification, boards need configuration tables telling which
2648 * chip is at which address.
2649 *
2650 * This must be called from context that can sleep. It returns zero on
2651 * success, else a negative error code (dropping the controller's refcount).
2652 * After a successful return, the caller is responsible for calling
2653 * spi_unregister_controller().
2654 *
2655 * Return: zero on success, else a negative error code.
2656 */
spi_register_controller(struct spi_controller * ctlr)2657 int spi_register_controller(struct spi_controller *ctlr)
2658 {
2659 struct device *dev = ctlr->dev.parent;
2660 struct boardinfo *bi;
2661 int status;
2662 int id, first_dynamic;
2663
2664 if (!dev)
2665 return -ENODEV;
2666
2667 /*
2668 * Make sure all necessary hooks are implemented before registering
2669 * the SPI controller.
2670 */
2671 status = spi_controller_check_ops(ctlr);
2672 if (status)
2673 return status;
2674
2675 if (ctlr->bus_num >= 0) {
2676 /* devices with a fixed bus num must check-in with the num */
2677 mutex_lock(&board_lock);
2678 id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2679 ctlr->bus_num + 1, GFP_KERNEL);
2680 mutex_unlock(&board_lock);
2681 if (WARN(id < 0, "couldn't get idr"))
2682 return id == -ENOSPC ? -EBUSY : id;
2683 ctlr->bus_num = id;
2684 } else if (ctlr->dev.of_node) {
2685 /* allocate dynamic bus number using Linux idr */
2686 id = of_alias_get_id(ctlr->dev.of_node, "spi");
2687 if (id >= 0) {
2688 ctlr->bus_num = id;
2689 mutex_lock(&board_lock);
2690 id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2691 ctlr->bus_num + 1, GFP_KERNEL);
2692 mutex_unlock(&board_lock);
2693 if (WARN(id < 0, "couldn't get idr"))
2694 return id == -ENOSPC ? -EBUSY : id;
2695 }
2696 }
2697 if (ctlr->bus_num < 0) {
2698 first_dynamic = of_alias_get_highest_id("spi");
2699 if (first_dynamic < 0)
2700 first_dynamic = 0;
2701 else
2702 first_dynamic++;
2703
2704 mutex_lock(&board_lock);
2705 id = idr_alloc(&spi_master_idr, ctlr, first_dynamic,
2706 0, GFP_KERNEL);
2707 mutex_unlock(&board_lock);
2708 if (WARN(id < 0, "couldn't get idr"))
2709 return id;
2710 ctlr->bus_num = id;
2711 }
2712 INIT_LIST_HEAD(&ctlr->queue);
2713 spin_lock_init(&ctlr->queue_lock);
2714 spin_lock_init(&ctlr->bus_lock_spinlock);
2715 mutex_init(&ctlr->bus_lock_mutex);
2716 mutex_init(&ctlr->io_mutex);
2717 ctlr->bus_lock_flag = 0;
2718 init_completion(&ctlr->xfer_completion);
2719 if (!ctlr->max_dma_len)
2720 ctlr->max_dma_len = INT_MAX;
2721
2722 /* register the device, then userspace will see it.
2723 * registration fails if the bus ID is in use.
2724 */
2725 dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num);
2726
2727 if (!spi_controller_is_slave(ctlr)) {
2728 if (ctlr->use_gpio_descriptors) {
2729 status = spi_get_gpio_descs(ctlr);
2730 if (status)
2731 goto free_bus_id;
2732 /*
2733 * A controller using GPIO descriptors always
2734 * supports SPI_CS_HIGH if need be.
2735 */
2736 ctlr->mode_bits |= SPI_CS_HIGH;
2737 } else {
2738 /* Legacy code path for GPIOs from DT */
2739 status = of_spi_get_gpio_numbers(ctlr);
2740 if (status)
2741 goto free_bus_id;
2742 }
2743 }
2744
2745 /*
2746 * Even if it's just one always-selected device, there must
2747 * be at least one chipselect.
2748 */
2749 if (!ctlr->num_chipselect) {
2750 status = -EINVAL;
2751 goto free_bus_id;
2752 }
2753
2754 status = device_add(&ctlr->dev);
2755 if (status < 0)
2756 goto free_bus_id;
2757 dev_dbg(dev, "registered %s %s\n",
2758 spi_controller_is_slave(ctlr) ? "slave" : "master",
2759 dev_name(&ctlr->dev));
2760
2761 /*
2762 * If we're using a queued driver, start the queue. Note that we don't
2763 * need the queueing logic if the driver is only supporting high-level
2764 * memory operations.
2765 */
2766 if (ctlr->transfer) {
2767 dev_info(dev, "controller is unqueued, this is deprecated\n");
2768 } else if (ctlr->transfer_one || ctlr->transfer_one_message) {
2769 status = spi_controller_initialize_queue(ctlr);
2770 if (status) {
2771 device_del(&ctlr->dev);
2772 goto free_bus_id;
2773 }
2774 }
2775 /* add statistics */
2776 spin_lock_init(&ctlr->statistics.lock);
2777
2778 mutex_lock(&board_lock);
2779 list_add_tail(&ctlr->list, &spi_controller_list);
2780 list_for_each_entry(bi, &board_list, list)
2781 spi_match_controller_to_boardinfo(ctlr, &bi->board_info);
2782 mutex_unlock(&board_lock);
2783
2784 /* Register devices from the device tree and ACPI */
2785 of_register_spi_devices(ctlr);
2786 acpi_register_spi_devices(ctlr);
2787 return status;
2788
2789 free_bus_id:
2790 mutex_lock(&board_lock);
2791 idr_remove(&spi_master_idr, ctlr->bus_num);
2792 mutex_unlock(&board_lock);
2793 return status;
2794 }
2795 EXPORT_SYMBOL_GPL(spi_register_controller);
2796
devm_spi_unregister(void * ctlr)2797 static void devm_spi_unregister(void *ctlr)
2798 {
2799 spi_unregister_controller(ctlr);
2800 }
2801
2802 /**
2803 * devm_spi_register_controller - register managed SPI master or slave
2804 * controller
2805 * @dev: device managing SPI controller
2806 * @ctlr: initialized controller, originally from spi_alloc_master() or
2807 * spi_alloc_slave()
2808 * Context: can sleep
2809 *
2810 * Register a SPI device as with spi_register_controller() which will
2811 * automatically be unregistered and freed.
2812 *
2813 * Return: zero on success, else a negative error code.
2814 */
devm_spi_register_controller(struct device * dev,struct spi_controller * ctlr)2815 int devm_spi_register_controller(struct device *dev,
2816 struct spi_controller *ctlr)
2817 {
2818 int ret;
2819
2820 ret = spi_register_controller(ctlr);
2821 if (ret)
2822 return ret;
2823
2824 return devm_add_action_or_reset(dev, devm_spi_unregister, ctlr);
2825 }
2826 EXPORT_SYMBOL_GPL(devm_spi_register_controller);
2827
__unregister(struct device * dev,void * null)2828 static int __unregister(struct device *dev, void *null)
2829 {
2830 spi_unregister_device(to_spi_device(dev));
2831 return 0;
2832 }
2833
2834 /**
2835 * spi_unregister_controller - unregister SPI master or slave controller
2836 * @ctlr: the controller being unregistered
2837 * Context: can sleep
2838 *
2839 * This call is used only by SPI controller drivers, which are the
2840 * only ones directly touching chip registers.
2841 *
2842 * This must be called from context that can sleep.
2843 *
2844 * Note that this function also drops a reference to the controller.
2845 */
spi_unregister_controller(struct spi_controller * ctlr)2846 void spi_unregister_controller(struct spi_controller *ctlr)
2847 {
2848 struct spi_controller *found;
2849 int id = ctlr->bus_num;
2850
2851 /* Prevent addition of new devices, unregister existing ones */
2852 if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
2853 mutex_lock(&spi_add_lock);
2854
2855 device_for_each_child(&ctlr->dev, NULL, __unregister);
2856
2857 /* First make sure that this controller was ever added */
2858 mutex_lock(&board_lock);
2859 found = idr_find(&spi_master_idr, id);
2860 mutex_unlock(&board_lock);
2861 if (ctlr->queued) {
2862 if (spi_destroy_queue(ctlr))
2863 dev_err(&ctlr->dev, "queue remove failed\n");
2864 }
2865 mutex_lock(&board_lock);
2866 list_del(&ctlr->list);
2867 mutex_unlock(&board_lock);
2868
2869 device_del(&ctlr->dev);
2870
2871 /* Release the last reference on the controller if its driver
2872 * has not yet been converted to devm_spi_alloc_master/slave().
2873 */
2874 if (!ctlr->devm_allocated)
2875 put_device(&ctlr->dev);
2876
2877 /* free bus id */
2878 mutex_lock(&board_lock);
2879 if (found == ctlr)
2880 idr_remove(&spi_master_idr, id);
2881 mutex_unlock(&board_lock);
2882
2883 if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
2884 mutex_unlock(&spi_add_lock);
2885 }
2886 EXPORT_SYMBOL_GPL(spi_unregister_controller);
2887
spi_controller_suspend(struct spi_controller * ctlr)2888 int spi_controller_suspend(struct spi_controller *ctlr)
2889 {
2890 int ret;
2891
2892 /* Basically no-ops for non-queued controllers */
2893 if (!ctlr->queued)
2894 return 0;
2895
2896 ret = spi_stop_queue(ctlr);
2897 if (ret)
2898 dev_err(&ctlr->dev, "queue stop failed\n");
2899
2900 return ret;
2901 }
2902 EXPORT_SYMBOL_GPL(spi_controller_suspend);
2903
spi_controller_resume(struct spi_controller * ctlr)2904 int spi_controller_resume(struct spi_controller *ctlr)
2905 {
2906 int ret;
2907
2908 if (!ctlr->queued)
2909 return 0;
2910
2911 ret = spi_start_queue(ctlr);
2912 if (ret)
2913 dev_err(&ctlr->dev, "queue restart failed\n");
2914
2915 return ret;
2916 }
2917 EXPORT_SYMBOL_GPL(spi_controller_resume);
2918
__spi_controller_match(struct device * dev,const void * data)2919 static int __spi_controller_match(struct device *dev, const void *data)
2920 {
2921 struct spi_controller *ctlr;
2922 const u16 *bus_num = data;
2923
2924 ctlr = container_of(dev, struct spi_controller, dev);
2925 return ctlr->bus_num == *bus_num;
2926 }
2927
2928 /**
2929 * spi_busnum_to_master - look up master associated with bus_num
2930 * @bus_num: the master's bus number
2931 * Context: can sleep
2932 *
2933 * This call may be used with devices that are registered after
2934 * arch init time. It returns a refcounted pointer to the relevant
2935 * spi_controller (which the caller must release), or NULL if there is
2936 * no such master registered.
2937 *
2938 * Return: the SPI master structure on success, else NULL.
2939 */
spi_busnum_to_master(u16 bus_num)2940 struct spi_controller *spi_busnum_to_master(u16 bus_num)
2941 {
2942 struct device *dev;
2943 struct spi_controller *ctlr = NULL;
2944
2945 dev = class_find_device(&spi_master_class, NULL, &bus_num,
2946 __spi_controller_match);
2947 if (dev)
2948 ctlr = container_of(dev, struct spi_controller, dev);
2949 /* reference got in class_find_device */
2950 return ctlr;
2951 }
2952 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2953
2954 /*-------------------------------------------------------------------------*/
2955
2956 /* Core methods for SPI resource management */
2957
2958 /**
2959 * spi_res_alloc - allocate a spi resource that is life-cycle managed
2960 * during the processing of a spi_message while using
2961 * spi_transfer_one
2962 * @spi: the spi device for which we allocate memory
2963 * @release: the release code to execute for this resource
2964 * @size: size to alloc and return
2965 * @gfp: GFP allocation flags
2966 *
2967 * Return: the pointer to the allocated data
2968 *
2969 * This may get enhanced in the future to allocate from a memory pool
2970 * of the @spi_device or @spi_controller to avoid repeated allocations.
2971 */
spi_res_alloc(struct spi_device * spi,spi_res_release_t release,size_t size,gfp_t gfp)2972 void *spi_res_alloc(struct spi_device *spi,
2973 spi_res_release_t release,
2974 size_t size, gfp_t gfp)
2975 {
2976 struct spi_res *sres;
2977
2978 sres = kzalloc(sizeof(*sres) + size, gfp);
2979 if (!sres)
2980 return NULL;
2981
2982 INIT_LIST_HEAD(&sres->entry);
2983 sres->release = release;
2984
2985 return sres->data;
2986 }
2987 EXPORT_SYMBOL_GPL(spi_res_alloc);
2988
2989 /**
2990 * spi_res_free - free an spi resource
2991 * @res: pointer to the custom data of a resource
2992 *
2993 */
spi_res_free(void * res)2994 void spi_res_free(void *res)
2995 {
2996 struct spi_res *sres = container_of(res, struct spi_res, data);
2997
2998 if (!res)
2999 return;
3000
3001 WARN_ON(!list_empty(&sres->entry));
3002 kfree(sres);
3003 }
3004 EXPORT_SYMBOL_GPL(spi_res_free);
3005
3006 /**
3007 * spi_res_add - add a spi_res to the spi_message
3008 * @message: the spi message
3009 * @res: the spi_resource
3010 */
spi_res_add(struct spi_message * message,void * res)3011 void spi_res_add(struct spi_message *message, void *res)
3012 {
3013 struct spi_res *sres = container_of(res, struct spi_res, data);
3014
3015 WARN_ON(!list_empty(&sres->entry));
3016 list_add_tail(&sres->entry, &message->resources);
3017 }
3018 EXPORT_SYMBOL_GPL(spi_res_add);
3019
3020 /**
3021 * spi_res_release - release all spi resources for this message
3022 * @ctlr: the @spi_controller
3023 * @message: the @spi_message
3024 */
spi_res_release(struct spi_controller * ctlr,struct spi_message * message)3025 void spi_res_release(struct spi_controller *ctlr, struct spi_message *message)
3026 {
3027 struct spi_res *res, *tmp;
3028
3029 list_for_each_entry_safe_reverse(res, tmp, &message->resources, entry) {
3030 if (res->release)
3031 res->release(ctlr, message, res->data);
3032
3033 list_del(&res->entry);
3034
3035 kfree(res);
3036 }
3037 }
3038 EXPORT_SYMBOL_GPL(spi_res_release);
3039
3040 /*-------------------------------------------------------------------------*/
3041
3042 /* Core methods for spi_message alterations */
3043
__spi_replace_transfers_release(struct spi_controller * ctlr,struct spi_message * msg,void * res)3044 static void __spi_replace_transfers_release(struct spi_controller *ctlr,
3045 struct spi_message *msg,
3046 void *res)
3047 {
3048 struct spi_replaced_transfers *rxfer = res;
3049 size_t i;
3050
3051 /* call extra callback if requested */
3052 if (rxfer->release)
3053 rxfer->release(ctlr, msg, res);
3054
3055 /* insert replaced transfers back into the message */
3056 list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
3057
3058 /* remove the formerly inserted entries */
3059 for (i = 0; i < rxfer->inserted; i++)
3060 list_del(&rxfer->inserted_transfers[i].transfer_list);
3061 }
3062
3063 /**
3064 * spi_replace_transfers - replace transfers with several transfers
3065 * and register change with spi_message.resources
3066 * @msg: the spi_message we work upon
3067 * @xfer_first: the first spi_transfer we want to replace
3068 * @remove: number of transfers to remove
3069 * @insert: the number of transfers we want to insert instead
3070 * @release: extra release code necessary in some circumstances
3071 * @extradatasize: extra data to allocate (with alignment guarantees
3072 * of struct @spi_transfer)
3073 * @gfp: gfp flags
3074 *
3075 * Returns: pointer to @spi_replaced_transfers,
3076 * PTR_ERR(...) in case of errors.
3077 */
spi_replace_transfers(struct spi_message * msg,struct spi_transfer * xfer_first,size_t remove,size_t insert,spi_replaced_release_t release,size_t extradatasize,gfp_t gfp)3078 struct spi_replaced_transfers *spi_replace_transfers(
3079 struct spi_message *msg,
3080 struct spi_transfer *xfer_first,
3081 size_t remove,
3082 size_t insert,
3083 spi_replaced_release_t release,
3084 size_t extradatasize,
3085 gfp_t gfp)
3086 {
3087 struct spi_replaced_transfers *rxfer;
3088 struct spi_transfer *xfer;
3089 size_t i;
3090
3091 /* allocate the structure using spi_res */
3092 rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
3093 struct_size(rxfer, inserted_transfers, insert)
3094 + extradatasize,
3095 gfp);
3096 if (!rxfer)
3097 return ERR_PTR(-ENOMEM);
3098
3099 /* the release code to invoke before running the generic release */
3100 rxfer->release = release;
3101
3102 /* assign extradata */
3103 if (extradatasize)
3104 rxfer->extradata =
3105 &rxfer->inserted_transfers[insert];
3106
3107 /* init the replaced_transfers list */
3108 INIT_LIST_HEAD(&rxfer->replaced_transfers);
3109
3110 /* assign the list_entry after which we should reinsert
3111 * the @replaced_transfers - it may be spi_message.messages!
3112 */
3113 rxfer->replaced_after = xfer_first->transfer_list.prev;
3114
3115 /* remove the requested number of transfers */
3116 for (i = 0; i < remove; i++) {
3117 /* if the entry after replaced_after it is msg->transfers
3118 * then we have been requested to remove more transfers
3119 * than are in the list
3120 */
3121 if (rxfer->replaced_after->next == &msg->transfers) {
3122 dev_err(&msg->spi->dev,
3123 "requested to remove more spi_transfers than are available\n");
3124 /* insert replaced transfers back into the message */
3125 list_splice(&rxfer->replaced_transfers,
3126 rxfer->replaced_after);
3127
3128 /* free the spi_replace_transfer structure */
3129 spi_res_free(rxfer);
3130
3131 /* and return with an error */
3132 return ERR_PTR(-EINVAL);
3133 }
3134
3135 /* remove the entry after replaced_after from list of
3136 * transfers and add it to list of replaced_transfers
3137 */
3138 list_move_tail(rxfer->replaced_after->next,
3139 &rxfer->replaced_transfers);
3140 }
3141
3142 /* create copy of the given xfer with identical settings
3143 * based on the first transfer to get removed
3144 */
3145 for (i = 0; i < insert; i++) {
3146 /* we need to run in reverse order */
3147 xfer = &rxfer->inserted_transfers[insert - 1 - i];
3148
3149 /* copy all spi_transfer data */
3150 memcpy(xfer, xfer_first, sizeof(*xfer));
3151
3152 /* add to list */
3153 list_add(&xfer->transfer_list, rxfer->replaced_after);
3154
3155 /* clear cs_change and delay for all but the last */
3156 if (i) {
3157 xfer->cs_change = false;
3158 xfer->delay.value = 0;
3159 }
3160 }
3161
3162 /* set up inserted */
3163 rxfer->inserted = insert;
3164
3165 /* and register it with spi_res/spi_message */
3166 spi_res_add(msg, rxfer);
3167
3168 return rxfer;
3169 }
3170 EXPORT_SYMBOL_GPL(spi_replace_transfers);
3171
__spi_split_transfer_maxsize(struct spi_controller * ctlr,struct spi_message * msg,struct spi_transfer ** xferp,size_t maxsize,gfp_t gfp)3172 static int __spi_split_transfer_maxsize(struct spi_controller *ctlr,
3173 struct spi_message *msg,
3174 struct spi_transfer **xferp,
3175 size_t maxsize,
3176 gfp_t gfp)
3177 {
3178 struct spi_transfer *xfer = *xferp, *xfers;
3179 struct spi_replaced_transfers *srt;
3180 size_t offset;
3181 size_t count, i;
3182
3183 /* calculate how many we have to replace */
3184 count = DIV_ROUND_UP(xfer->len, maxsize);
3185
3186 /* create replacement */
3187 srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
3188 if (IS_ERR(srt))
3189 return PTR_ERR(srt);
3190 xfers = srt->inserted_transfers;
3191
3192 /* now handle each of those newly inserted spi_transfers
3193 * note that the replacements spi_transfers all are preset
3194 * to the same values as *xferp, so tx_buf, rx_buf and len
3195 * are all identical (as well as most others)
3196 * so we just have to fix up len and the pointers.
3197 *
3198 * this also includes support for the depreciated
3199 * spi_message.is_dma_mapped interface
3200 */
3201
3202 /* the first transfer just needs the length modified, so we
3203 * run it outside the loop
3204 */
3205 xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
3206
3207 /* all the others need rx_buf/tx_buf also set */
3208 for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
3209 /* update rx_buf, tx_buf and dma */
3210 if (xfers[i].rx_buf)
3211 xfers[i].rx_buf += offset;
3212 if (xfers[i].rx_dma)
3213 xfers[i].rx_dma += offset;
3214 if (xfers[i].tx_buf)
3215 xfers[i].tx_buf += offset;
3216 if (xfers[i].tx_dma)
3217 xfers[i].tx_dma += offset;
3218
3219 /* update length */
3220 xfers[i].len = min(maxsize, xfers[i].len - offset);
3221 }
3222
3223 /* we set up xferp to the last entry we have inserted,
3224 * so that we skip those already split transfers
3225 */
3226 *xferp = &xfers[count - 1];
3227
3228 /* increment statistics counters */
3229 SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
3230 transfers_split_maxsize);
3231 SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
3232 transfers_split_maxsize);
3233
3234 return 0;
3235 }
3236
3237 /**
3238 * spi_split_transfers_maxsize - split spi transfers into multiple transfers
3239 * when an individual transfer exceeds a
3240 * certain size
3241 * @ctlr: the @spi_controller for this transfer
3242 * @msg: the @spi_message to transform
3243 * @maxsize: the maximum when to apply this
3244 * @gfp: GFP allocation flags
3245 *
3246 * Return: status of transformation
3247 */
spi_split_transfers_maxsize(struct spi_controller * ctlr,struct spi_message * msg,size_t maxsize,gfp_t gfp)3248 int spi_split_transfers_maxsize(struct spi_controller *ctlr,
3249 struct spi_message *msg,
3250 size_t maxsize,
3251 gfp_t gfp)
3252 {
3253 struct spi_transfer *xfer;
3254 int ret;
3255
3256 /* iterate over the transfer_list,
3257 * but note that xfer is advanced to the last transfer inserted
3258 * to avoid checking sizes again unnecessarily (also xfer does
3259 * potentiall belong to a different list by the time the
3260 * replacement has happened
3261 */
3262 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
3263 if (xfer->len > maxsize) {
3264 ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
3265 maxsize, gfp);
3266 if (ret)
3267 return ret;
3268 }
3269 }
3270
3271 return 0;
3272 }
3273 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
3274
3275 /*-------------------------------------------------------------------------*/
3276
3277 /* Core methods for SPI controller protocol drivers. Some of the
3278 * other core methods are currently defined as inline functions.
3279 */
3280
__spi_validate_bits_per_word(struct spi_controller * ctlr,u8 bits_per_word)3281 static int __spi_validate_bits_per_word(struct spi_controller *ctlr,
3282 u8 bits_per_word)
3283 {
3284 if (ctlr->bits_per_word_mask) {
3285 /* Only 32 bits fit in the mask */
3286 if (bits_per_word > 32)
3287 return -EINVAL;
3288 if (!(ctlr->bits_per_word_mask & SPI_BPW_MASK(bits_per_word)))
3289 return -EINVAL;
3290 }
3291
3292 return 0;
3293 }
3294
3295 /**
3296 * spi_setup - setup SPI mode and clock rate
3297 * @spi: the device whose settings are being modified
3298 * Context: can sleep, and no requests are queued to the device
3299 *
3300 * SPI protocol drivers may need to update the transfer mode if the
3301 * device doesn't work with its default. They may likewise need
3302 * to update clock rates or word sizes from initial values. This function
3303 * changes those settings, and must be called from a context that can sleep.
3304 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
3305 * effect the next time the device is selected and data is transferred to
3306 * or from it. When this function returns, the spi device is deselected.
3307 *
3308 * Note that this call will fail if the protocol driver specifies an option
3309 * that the underlying controller or its driver does not support. For
3310 * example, not all hardware supports wire transfers using nine bit words,
3311 * LSB-first wire encoding, or active-high chipselects.
3312 *
3313 * Return: zero on success, else a negative error code.
3314 */
spi_setup(struct spi_device * spi)3315 int spi_setup(struct spi_device *spi)
3316 {
3317 unsigned bad_bits, ugly_bits;
3318 int status;
3319
3320 /*
3321 * check mode to prevent that any two of DUAL, QUAD and NO_MOSI/MISO
3322 * are set at the same time
3323 */
3324 if ((hweight_long(spi->mode &
3325 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_NO_TX)) > 1) ||
3326 (hweight_long(spi->mode &
3327 (SPI_RX_DUAL | SPI_RX_QUAD | SPI_NO_RX)) > 1)) {
3328 dev_err(&spi->dev,
3329 "setup: can not select any two of dual, quad and no-rx/tx at the same time\n");
3330 return -EINVAL;
3331 }
3332 /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
3333 */
3334 if ((spi->mode & SPI_3WIRE) && (spi->mode &
3335 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3336 SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL)))
3337 return -EINVAL;
3338 /* help drivers fail *cleanly* when they need options
3339 * that aren't supported with their current controller
3340 * SPI_CS_WORD has a fallback software implementation,
3341 * so it is ignored here.
3342 */
3343 bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD |
3344 SPI_NO_TX | SPI_NO_RX);
3345 /* nothing prevents from working with active-high CS in case if it
3346 * is driven by GPIO.
3347 */
3348 if (gpio_is_valid(spi->cs_gpio))
3349 bad_bits &= ~SPI_CS_HIGH;
3350 ugly_bits = bad_bits &
3351 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3352 SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL);
3353 if (ugly_bits) {
3354 dev_warn(&spi->dev,
3355 "setup: ignoring unsupported mode bits %x\n",
3356 ugly_bits);
3357 spi->mode &= ~ugly_bits;
3358 bad_bits &= ~ugly_bits;
3359 }
3360 if (bad_bits) {
3361 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
3362 bad_bits);
3363 return -EINVAL;
3364 }
3365
3366 if (!spi->bits_per_word)
3367 spi->bits_per_word = 8;
3368
3369 status = __spi_validate_bits_per_word(spi->controller,
3370 spi->bits_per_word);
3371 if (status)
3372 return status;
3373
3374 if (spi->controller->max_speed_hz &&
3375 (!spi->max_speed_hz ||
3376 spi->max_speed_hz > spi->controller->max_speed_hz))
3377 spi->max_speed_hz = spi->controller->max_speed_hz;
3378
3379 mutex_lock(&spi->controller->io_mutex);
3380
3381 if (spi->controller->setup) {
3382 status = spi->controller->setup(spi);
3383 if (status) {
3384 mutex_unlock(&spi->controller->io_mutex);
3385 dev_err(&spi->controller->dev, "Failed to setup device: %d\n",
3386 status);
3387 return status;
3388 }
3389 }
3390
3391 if (spi->controller->auto_runtime_pm && spi->controller->set_cs) {
3392 status = pm_runtime_get_sync(spi->controller->dev.parent);
3393 if (status < 0) {
3394 mutex_unlock(&spi->controller->io_mutex);
3395 pm_runtime_put_noidle(spi->controller->dev.parent);
3396 dev_err(&spi->controller->dev, "Failed to power device: %d\n",
3397 status);
3398 return status;
3399 }
3400
3401 /*
3402 * We do not want to return positive value from pm_runtime_get,
3403 * there are many instances of devices calling spi_setup() and
3404 * checking for a non-zero return value instead of a negative
3405 * return value.
3406 */
3407 status = 0;
3408
3409 spi_set_cs(spi, false, true);
3410 pm_runtime_mark_last_busy(spi->controller->dev.parent);
3411 pm_runtime_put_autosuspend(spi->controller->dev.parent);
3412 } else {
3413 spi_set_cs(spi, false, true);
3414 }
3415
3416 mutex_unlock(&spi->controller->io_mutex);
3417
3418 if (spi->rt && !spi->controller->rt) {
3419 spi->controller->rt = true;
3420 spi_set_thread_rt(spi->controller);
3421 }
3422
3423 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
3424 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
3425 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
3426 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
3427 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
3428 (spi->mode & SPI_LOOP) ? "loopback, " : "",
3429 spi->bits_per_word, spi->max_speed_hz,
3430 status);
3431
3432 return status;
3433 }
3434 EXPORT_SYMBOL_GPL(spi_setup);
3435
3436 /**
3437 * spi_set_cs_timing - configure CS setup, hold, and inactive delays
3438 * @spi: the device that requires specific CS timing configuration
3439 * @setup: CS setup time specified via @spi_delay
3440 * @hold: CS hold time specified via @spi_delay
3441 * @inactive: CS inactive delay between transfers specified via @spi_delay
3442 *
3443 * Return: zero on success, else a negative error code.
3444 */
spi_set_cs_timing(struct spi_device * spi,struct spi_delay * setup,struct spi_delay * hold,struct spi_delay * inactive)3445 int spi_set_cs_timing(struct spi_device *spi, struct spi_delay *setup,
3446 struct spi_delay *hold, struct spi_delay *inactive)
3447 {
3448 struct device *parent = spi->controller->dev.parent;
3449 size_t len;
3450 int status;
3451
3452 if (spi->controller->set_cs_timing &&
3453 !(spi->cs_gpiod || gpio_is_valid(spi->cs_gpio))) {
3454 if (spi->controller->auto_runtime_pm) {
3455 status = pm_runtime_get_sync(parent);
3456 if (status < 0) {
3457 pm_runtime_put_noidle(parent);
3458 dev_err(&spi->controller->dev, "Failed to power device: %d\n",
3459 status);
3460 return status;
3461 }
3462
3463 status = spi->controller->set_cs_timing(spi, setup,
3464 hold, inactive);
3465 pm_runtime_mark_last_busy(parent);
3466 pm_runtime_put_autosuspend(parent);
3467 return status;
3468 } else {
3469 return spi->controller->set_cs_timing(spi, setup, hold,
3470 inactive);
3471 }
3472 }
3473
3474 if ((setup && setup->unit == SPI_DELAY_UNIT_SCK) ||
3475 (hold && hold->unit == SPI_DELAY_UNIT_SCK) ||
3476 (inactive && inactive->unit == SPI_DELAY_UNIT_SCK)) {
3477 dev_err(&spi->dev,
3478 "Clock-cycle delays for CS not supported in SW mode\n");
3479 return -ENOTSUPP;
3480 }
3481
3482 len = sizeof(struct spi_delay);
3483
3484 /* copy delays to controller */
3485 if (setup)
3486 memcpy(&spi->controller->cs_setup, setup, len);
3487 else
3488 memset(&spi->controller->cs_setup, 0, len);
3489
3490 if (hold)
3491 memcpy(&spi->controller->cs_hold, hold, len);
3492 else
3493 memset(&spi->controller->cs_hold, 0, len);
3494
3495 if (inactive)
3496 memcpy(&spi->controller->cs_inactive, inactive, len);
3497 else
3498 memset(&spi->controller->cs_inactive, 0, len);
3499
3500 return 0;
3501 }
3502 EXPORT_SYMBOL_GPL(spi_set_cs_timing);
3503
_spi_xfer_word_delay_update(struct spi_transfer * xfer,struct spi_device * spi)3504 static int _spi_xfer_word_delay_update(struct spi_transfer *xfer,
3505 struct spi_device *spi)
3506 {
3507 int delay1, delay2;
3508
3509 delay1 = spi_delay_to_ns(&xfer->word_delay, xfer);
3510 if (delay1 < 0)
3511 return delay1;
3512
3513 delay2 = spi_delay_to_ns(&spi->word_delay, xfer);
3514 if (delay2 < 0)
3515 return delay2;
3516
3517 if (delay1 < delay2)
3518 memcpy(&xfer->word_delay, &spi->word_delay,
3519 sizeof(xfer->word_delay));
3520
3521 return 0;
3522 }
3523
__spi_validate(struct spi_device * spi,struct spi_message * message)3524 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
3525 {
3526 struct spi_controller *ctlr = spi->controller;
3527 struct spi_transfer *xfer;
3528 int w_size;
3529
3530 if (list_empty(&message->transfers))
3531 return -EINVAL;
3532
3533 /* If an SPI controller does not support toggling the CS line on each
3534 * transfer (indicated by the SPI_CS_WORD flag) or we are using a GPIO
3535 * for the CS line, we can emulate the CS-per-word hardware function by
3536 * splitting transfers into one-word transfers and ensuring that
3537 * cs_change is set for each transfer.
3538 */
3539 if ((spi->mode & SPI_CS_WORD) && (!(ctlr->mode_bits & SPI_CS_WORD) ||
3540 spi->cs_gpiod ||
3541 gpio_is_valid(spi->cs_gpio))) {
3542 size_t maxsize;
3543 int ret;
3544
3545 maxsize = (spi->bits_per_word + 7) / 8;
3546
3547 /* spi_split_transfers_maxsize() requires message->spi */
3548 message->spi = spi;
3549
3550 ret = spi_split_transfers_maxsize(ctlr, message, maxsize,
3551 GFP_KERNEL);
3552 if (ret)
3553 return ret;
3554
3555 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3556 /* don't change cs_change on the last entry in the list */
3557 if (list_is_last(&xfer->transfer_list, &message->transfers))
3558 break;
3559 xfer->cs_change = 1;
3560 }
3561 }
3562
3563 /* Half-duplex links include original MicroWire, and ones with
3564 * only one data pin like SPI_3WIRE (switches direction) or where
3565 * either MOSI or MISO is missing. They can also be caused by
3566 * software limitations.
3567 */
3568 if ((ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX) ||
3569 (spi->mode & SPI_3WIRE)) {
3570 unsigned flags = ctlr->flags;
3571
3572 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3573 if (xfer->rx_buf && xfer->tx_buf)
3574 return -EINVAL;
3575 if ((flags & SPI_CONTROLLER_NO_TX) && xfer->tx_buf)
3576 return -EINVAL;
3577 if ((flags & SPI_CONTROLLER_NO_RX) && xfer->rx_buf)
3578 return -EINVAL;
3579 }
3580 }
3581
3582 /**
3583 * Set transfer bits_per_word and max speed as spi device default if
3584 * it is not set for this transfer.
3585 * Set transfer tx_nbits and rx_nbits as single transfer default
3586 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
3587 * Ensure transfer word_delay is at least as long as that required by
3588 * device itself.
3589 */
3590 message->frame_length = 0;
3591 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3592 xfer->effective_speed_hz = 0;
3593 message->frame_length += xfer->len;
3594 if (!xfer->bits_per_word)
3595 xfer->bits_per_word = spi->bits_per_word;
3596
3597 if (!xfer->speed_hz)
3598 xfer->speed_hz = spi->max_speed_hz;
3599
3600 if (ctlr->max_speed_hz && xfer->speed_hz > ctlr->max_speed_hz)
3601 xfer->speed_hz = ctlr->max_speed_hz;
3602
3603 if (__spi_validate_bits_per_word(ctlr, xfer->bits_per_word))
3604 return -EINVAL;
3605
3606 /*
3607 * SPI transfer length should be multiple of SPI word size
3608 * where SPI word size should be power-of-two multiple
3609 */
3610 if (xfer->bits_per_word <= 8)
3611 w_size = 1;
3612 else if (xfer->bits_per_word <= 16)
3613 w_size = 2;
3614 else
3615 w_size = 4;
3616
3617 /* No partial transfers accepted */
3618 if (xfer->len % w_size)
3619 return -EINVAL;
3620
3621 if (xfer->speed_hz && ctlr->min_speed_hz &&
3622 xfer->speed_hz < ctlr->min_speed_hz)
3623 return -EINVAL;
3624
3625 if (xfer->tx_buf && !xfer->tx_nbits)
3626 xfer->tx_nbits = SPI_NBITS_SINGLE;
3627 if (xfer->rx_buf && !xfer->rx_nbits)
3628 xfer->rx_nbits = SPI_NBITS_SINGLE;
3629 /* check transfer tx/rx_nbits:
3630 * 1. check the value matches one of single, dual and quad
3631 * 2. check tx/rx_nbits match the mode in spi_device
3632 */
3633 if (xfer->tx_buf) {
3634 if (spi->mode & SPI_NO_TX)
3635 return -EINVAL;
3636 if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
3637 xfer->tx_nbits != SPI_NBITS_DUAL &&
3638 xfer->tx_nbits != SPI_NBITS_QUAD)
3639 return -EINVAL;
3640 if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
3641 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
3642 return -EINVAL;
3643 if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
3644 !(spi->mode & SPI_TX_QUAD))
3645 return -EINVAL;
3646 }
3647 /* check transfer rx_nbits */
3648 if (xfer->rx_buf) {
3649 if (spi->mode & SPI_NO_RX)
3650 return -EINVAL;
3651 if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
3652 xfer->rx_nbits != SPI_NBITS_DUAL &&
3653 xfer->rx_nbits != SPI_NBITS_QUAD)
3654 return -EINVAL;
3655 if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
3656 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
3657 return -EINVAL;
3658 if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
3659 !(spi->mode & SPI_RX_QUAD))
3660 return -EINVAL;
3661 }
3662
3663 if (_spi_xfer_word_delay_update(xfer, spi))
3664 return -EINVAL;
3665 }
3666
3667 message->status = -EINPROGRESS;
3668
3669 return 0;
3670 }
3671
__spi_async(struct spi_device * spi,struct spi_message * message)3672 static int __spi_async(struct spi_device *spi, struct spi_message *message)
3673 {
3674 struct spi_controller *ctlr = spi->controller;
3675 struct spi_transfer *xfer;
3676
3677 /*
3678 * Some controllers do not support doing regular SPI transfers. Return
3679 * ENOTSUPP when this is the case.
3680 */
3681 if (!ctlr->transfer)
3682 return -ENOTSUPP;
3683
3684 message->spi = spi;
3685
3686 SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_async);
3687 SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
3688
3689 trace_spi_message_submit(message);
3690
3691 if (!ctlr->ptp_sts_supported) {
3692 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3693 xfer->ptp_sts_word_pre = 0;
3694 ptp_read_system_prets(xfer->ptp_sts);
3695 }
3696 }
3697
3698 return ctlr->transfer(spi, message);
3699 }
3700
3701 /**
3702 * spi_async - asynchronous SPI transfer
3703 * @spi: device with which data will be exchanged
3704 * @message: describes the data transfers, including completion callback
3705 * Context: any (irqs may be blocked, etc)
3706 *
3707 * This call may be used in_irq and other contexts which can't sleep,
3708 * as well as from task contexts which can sleep.
3709 *
3710 * The completion callback is invoked in a context which can't sleep.
3711 * Before that invocation, the value of message->status is undefined.
3712 * When the callback is issued, message->status holds either zero (to
3713 * indicate complete success) or a negative error code. After that
3714 * callback returns, the driver which issued the transfer request may
3715 * deallocate the associated memory; it's no longer in use by any SPI
3716 * core or controller driver code.
3717 *
3718 * Note that although all messages to a spi_device are handled in
3719 * FIFO order, messages may go to different devices in other orders.
3720 * Some device might be higher priority, or have various "hard" access
3721 * time requirements, for example.
3722 *
3723 * On detection of any fault during the transfer, processing of
3724 * the entire message is aborted, and the device is deselected.
3725 * Until returning from the associated message completion callback,
3726 * no other spi_message queued to that device will be processed.
3727 * (This rule applies equally to all the synchronous transfer calls,
3728 * which are wrappers around this core asynchronous primitive.)
3729 *
3730 * Return: zero on success, else a negative error code.
3731 */
spi_async(struct spi_device * spi,struct spi_message * message)3732 int spi_async(struct spi_device *spi, struct spi_message *message)
3733 {
3734 struct spi_controller *ctlr = spi->controller;
3735 int ret;
3736 unsigned long flags;
3737
3738 ret = __spi_validate(spi, message);
3739 if (ret != 0)
3740 return ret;
3741
3742 spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3743
3744 if (ctlr->bus_lock_flag)
3745 ret = -EBUSY;
3746 else
3747 ret = __spi_async(spi, message);
3748
3749 spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3750
3751 return ret;
3752 }
3753 EXPORT_SYMBOL_GPL(spi_async);
3754
3755 /**
3756 * spi_async_locked - version of spi_async with exclusive bus usage
3757 * @spi: device with which data will be exchanged
3758 * @message: describes the data transfers, including completion callback
3759 * Context: any (irqs may be blocked, etc)
3760 *
3761 * This call may be used in_irq and other contexts which can't sleep,
3762 * as well as from task contexts which can sleep.
3763 *
3764 * The completion callback is invoked in a context which can't sleep.
3765 * Before that invocation, the value of message->status is undefined.
3766 * When the callback is issued, message->status holds either zero (to
3767 * indicate complete success) or a negative error code. After that
3768 * callback returns, the driver which issued the transfer request may
3769 * deallocate the associated memory; it's no longer in use by any SPI
3770 * core or controller driver code.
3771 *
3772 * Note that although all messages to a spi_device are handled in
3773 * FIFO order, messages may go to different devices in other orders.
3774 * Some device might be higher priority, or have various "hard" access
3775 * time requirements, for example.
3776 *
3777 * On detection of any fault during the transfer, processing of
3778 * the entire message is aborted, and the device is deselected.
3779 * Until returning from the associated message completion callback,
3780 * no other spi_message queued to that device will be processed.
3781 * (This rule applies equally to all the synchronous transfer calls,
3782 * which are wrappers around this core asynchronous primitive.)
3783 *
3784 * Return: zero on success, else a negative error code.
3785 */
spi_async_locked(struct spi_device * spi,struct spi_message * message)3786 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
3787 {
3788 struct spi_controller *ctlr = spi->controller;
3789 int ret;
3790 unsigned long flags;
3791
3792 ret = __spi_validate(spi, message);
3793 if (ret != 0)
3794 return ret;
3795
3796 spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3797
3798 ret = __spi_async(spi, message);
3799
3800 spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3801
3802 return ret;
3803
3804 }
3805 EXPORT_SYMBOL_GPL(spi_async_locked);
3806
3807 /*-------------------------------------------------------------------------*/
3808
3809 /* Utility methods for SPI protocol drivers, layered on
3810 * top of the core. Some other utility methods are defined as
3811 * inline functions.
3812 */
3813
spi_complete(void * arg)3814 static void spi_complete(void *arg)
3815 {
3816 complete(arg);
3817 }
3818
__spi_sync(struct spi_device * spi,struct spi_message * message)3819 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
3820 {
3821 DECLARE_COMPLETION_ONSTACK(done);
3822 int status;
3823 struct spi_controller *ctlr = spi->controller;
3824 unsigned long flags;
3825
3826 status = __spi_validate(spi, message);
3827 if (status != 0)
3828 return status;
3829
3830 message->complete = spi_complete;
3831 message->context = &done;
3832 message->spi = spi;
3833
3834 SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_sync);
3835 SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
3836
3837 /* If we're not using the legacy transfer method then we will
3838 * try to transfer in the calling context so special case.
3839 * This code would be less tricky if we could remove the
3840 * support for driver implemented message queues.
3841 */
3842 if (ctlr->transfer == spi_queued_transfer) {
3843 spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3844
3845 trace_spi_message_submit(message);
3846
3847 status = __spi_queued_transfer(spi, message, false);
3848
3849 spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3850 } else {
3851 status = spi_async_locked(spi, message);
3852 }
3853
3854 if (status == 0) {
3855 /* Push out the messages in the calling context if we
3856 * can.
3857 */
3858 if (ctlr->transfer == spi_queued_transfer) {
3859 SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
3860 spi_sync_immediate);
3861 SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
3862 spi_sync_immediate);
3863 __spi_pump_messages(ctlr, false);
3864 }
3865
3866 wait_for_completion(&done);
3867 status = message->status;
3868 }
3869 message->context = NULL;
3870 return status;
3871 }
3872
3873 /**
3874 * spi_sync - blocking/synchronous SPI data transfers
3875 * @spi: device with which data will be exchanged
3876 * @message: describes the data transfers
3877 * Context: can sleep
3878 *
3879 * This call may only be used from a context that may sleep. The sleep
3880 * is non-interruptible, and has no timeout. Low-overhead controller
3881 * drivers may DMA directly into and out of the message buffers.
3882 *
3883 * Note that the SPI device's chip select is active during the message,
3884 * and then is normally disabled between messages. Drivers for some
3885 * frequently-used devices may want to minimize costs of selecting a chip,
3886 * by leaving it selected in anticipation that the next message will go
3887 * to the same chip. (That may increase power usage.)
3888 *
3889 * Also, the caller is guaranteeing that the memory associated with the
3890 * message will not be freed before this call returns.
3891 *
3892 * Return: zero on success, else a negative error code.
3893 */
spi_sync(struct spi_device * spi,struct spi_message * message)3894 int spi_sync(struct spi_device *spi, struct spi_message *message)
3895 {
3896 int ret;
3897
3898 mutex_lock(&spi->controller->bus_lock_mutex);
3899 ret = __spi_sync(spi, message);
3900 mutex_unlock(&spi->controller->bus_lock_mutex);
3901
3902 return ret;
3903 }
3904 EXPORT_SYMBOL_GPL(spi_sync);
3905
3906 /**
3907 * spi_sync_locked - version of spi_sync with exclusive bus usage
3908 * @spi: device with which data will be exchanged
3909 * @message: describes the data transfers
3910 * Context: can sleep
3911 *
3912 * This call may only be used from a context that may sleep. The sleep
3913 * is non-interruptible, and has no timeout. Low-overhead controller
3914 * drivers may DMA directly into and out of the message buffers.
3915 *
3916 * This call should be used by drivers that require exclusive access to the
3917 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
3918 * be released by a spi_bus_unlock call when the exclusive access is over.
3919 *
3920 * Return: zero on success, else a negative error code.
3921 */
spi_sync_locked(struct spi_device * spi,struct spi_message * message)3922 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
3923 {
3924 return __spi_sync(spi, message);
3925 }
3926 EXPORT_SYMBOL_GPL(spi_sync_locked);
3927
3928 /**
3929 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
3930 * @ctlr: SPI bus master that should be locked for exclusive bus access
3931 * Context: can sleep
3932 *
3933 * This call may only be used from a context that may sleep. The sleep
3934 * is non-interruptible, and has no timeout.
3935 *
3936 * This call should be used by drivers that require exclusive access to the
3937 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
3938 * exclusive access is over. Data transfer must be done by spi_sync_locked
3939 * and spi_async_locked calls when the SPI bus lock is held.
3940 *
3941 * Return: always zero.
3942 */
spi_bus_lock(struct spi_controller * ctlr)3943 int spi_bus_lock(struct spi_controller *ctlr)
3944 {
3945 unsigned long flags;
3946
3947 mutex_lock(&ctlr->bus_lock_mutex);
3948
3949 spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3950 ctlr->bus_lock_flag = 1;
3951 spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3952
3953 /* mutex remains locked until spi_bus_unlock is called */
3954
3955 return 0;
3956 }
3957 EXPORT_SYMBOL_GPL(spi_bus_lock);
3958
3959 /**
3960 * spi_bus_unlock - release the lock for exclusive SPI bus usage
3961 * @ctlr: SPI bus master that was locked for exclusive bus access
3962 * Context: can sleep
3963 *
3964 * This call may only be used from a context that may sleep. The sleep
3965 * is non-interruptible, and has no timeout.
3966 *
3967 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
3968 * call.
3969 *
3970 * Return: always zero.
3971 */
spi_bus_unlock(struct spi_controller * ctlr)3972 int spi_bus_unlock(struct spi_controller *ctlr)
3973 {
3974 ctlr->bus_lock_flag = 0;
3975
3976 mutex_unlock(&ctlr->bus_lock_mutex);
3977
3978 return 0;
3979 }
3980 EXPORT_SYMBOL_GPL(spi_bus_unlock);
3981
3982 /* portable code must never pass more than 32 bytes */
3983 #define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
3984
3985 static u8 *buf;
3986
3987 /**
3988 * spi_write_then_read - SPI synchronous write followed by read
3989 * @spi: device with which data will be exchanged
3990 * @txbuf: data to be written (need not be dma-safe)
3991 * @n_tx: size of txbuf, in bytes
3992 * @rxbuf: buffer into which data will be read (need not be dma-safe)
3993 * @n_rx: size of rxbuf, in bytes
3994 * Context: can sleep
3995 *
3996 * This performs a half duplex MicroWire style transaction with the
3997 * device, sending txbuf and then reading rxbuf. The return value
3998 * is zero for success, else a negative errno status code.
3999 * This call may only be used from a context that may sleep.
4000 *
4001 * Parameters to this routine are always copied using a small buffer.
4002 * Performance-sensitive or bulk transfer code should instead use
4003 * spi_{async,sync}() calls with dma-safe buffers.
4004 *
4005 * Return: zero on success, else a negative error code.
4006 */
spi_write_then_read(struct spi_device * spi,const void * txbuf,unsigned n_tx,void * rxbuf,unsigned n_rx)4007 int spi_write_then_read(struct spi_device *spi,
4008 const void *txbuf, unsigned n_tx,
4009 void *rxbuf, unsigned n_rx)
4010 {
4011 static DEFINE_MUTEX(lock);
4012
4013 int status;
4014 struct spi_message message;
4015 struct spi_transfer x[2];
4016 u8 *local_buf;
4017
4018 /* Use preallocated DMA-safe buffer if we can. We can't avoid
4019 * copying here, (as a pure convenience thing), but we can
4020 * keep heap costs out of the hot path unless someone else is
4021 * using the pre-allocated buffer or the transfer is too large.
4022 */
4023 if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
4024 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
4025 GFP_KERNEL | GFP_DMA);
4026 if (!local_buf)
4027 return -ENOMEM;
4028 } else {
4029 local_buf = buf;
4030 }
4031
4032 spi_message_init(&message);
4033 memset(x, 0, sizeof(x));
4034 if (n_tx) {
4035 x[0].len = n_tx;
4036 spi_message_add_tail(&x[0], &message);
4037 }
4038 if (n_rx) {
4039 x[1].len = n_rx;
4040 spi_message_add_tail(&x[1], &message);
4041 }
4042
4043 memcpy(local_buf, txbuf, n_tx);
4044 x[0].tx_buf = local_buf;
4045 x[1].rx_buf = local_buf + n_tx;
4046
4047 /* do the i/o */
4048 status = spi_sync(spi, &message);
4049 if (status == 0)
4050 memcpy(rxbuf, x[1].rx_buf, n_rx);
4051
4052 if (x[0].tx_buf == buf)
4053 mutex_unlock(&lock);
4054 else
4055 kfree(local_buf);
4056
4057 return status;
4058 }
4059 EXPORT_SYMBOL_GPL(spi_write_then_read);
4060
4061 /*-------------------------------------------------------------------------*/
4062
4063 #if IS_ENABLED(CONFIG_OF)
4064 /* must call put_device() when done with returned spi_device device */
of_find_spi_device_by_node(struct device_node * node)4065 struct spi_device *of_find_spi_device_by_node(struct device_node *node)
4066 {
4067 struct device *dev = bus_find_device_by_of_node(&spi_bus_type, node);
4068
4069 return dev ? to_spi_device(dev) : NULL;
4070 }
4071 EXPORT_SYMBOL_GPL(of_find_spi_device_by_node);
4072 #endif /* IS_ENABLED(CONFIG_OF) */
4073
4074 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
4075 /* the spi controllers are not using spi_bus, so we find it with another way */
of_find_spi_controller_by_node(struct device_node * node)4076 static struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
4077 {
4078 struct device *dev;
4079
4080 dev = class_find_device_by_of_node(&spi_master_class, node);
4081 if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
4082 dev = class_find_device_by_of_node(&spi_slave_class, node);
4083 if (!dev)
4084 return NULL;
4085
4086 /* reference got in class_find_device */
4087 return container_of(dev, struct spi_controller, dev);
4088 }
4089
of_spi_notify(struct notifier_block * nb,unsigned long action,void * arg)4090 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
4091 void *arg)
4092 {
4093 struct of_reconfig_data *rd = arg;
4094 struct spi_controller *ctlr;
4095 struct spi_device *spi;
4096
4097 switch (of_reconfig_get_state_change(action, arg)) {
4098 case OF_RECONFIG_CHANGE_ADD:
4099 ctlr = of_find_spi_controller_by_node(rd->dn->parent);
4100 if (ctlr == NULL)
4101 return NOTIFY_OK; /* not for us */
4102
4103 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
4104 put_device(&ctlr->dev);
4105 return NOTIFY_OK;
4106 }
4107
4108 spi = of_register_spi_device(ctlr, rd->dn);
4109 put_device(&ctlr->dev);
4110
4111 if (IS_ERR(spi)) {
4112 pr_err("%s: failed to create for '%pOF'\n",
4113 __func__, rd->dn);
4114 of_node_clear_flag(rd->dn, OF_POPULATED);
4115 return notifier_from_errno(PTR_ERR(spi));
4116 }
4117 break;
4118
4119 case OF_RECONFIG_CHANGE_REMOVE:
4120 /* already depopulated? */
4121 if (!of_node_check_flag(rd->dn, OF_POPULATED))
4122 return NOTIFY_OK;
4123
4124 /* find our device by node */
4125 spi = of_find_spi_device_by_node(rd->dn);
4126 if (spi == NULL)
4127 return NOTIFY_OK; /* no? not meant for us */
4128
4129 /* unregister takes one ref away */
4130 spi_unregister_device(spi);
4131
4132 /* and put the reference of the find */
4133 put_device(&spi->dev);
4134 break;
4135 }
4136
4137 return NOTIFY_OK;
4138 }
4139
4140 static struct notifier_block spi_of_notifier = {
4141 .notifier_call = of_spi_notify,
4142 };
4143 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
4144 extern struct notifier_block spi_of_notifier;
4145 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
4146
4147 #if IS_ENABLED(CONFIG_ACPI)
spi_acpi_controller_match(struct device * dev,const void * data)4148 static int spi_acpi_controller_match(struct device *dev, const void *data)
4149 {
4150 return ACPI_COMPANION(dev->parent) == data;
4151 }
4152
acpi_spi_find_controller_by_adev(struct acpi_device * adev)4153 static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev)
4154 {
4155 struct device *dev;
4156
4157 dev = class_find_device(&spi_master_class, NULL, adev,
4158 spi_acpi_controller_match);
4159 if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
4160 dev = class_find_device(&spi_slave_class, NULL, adev,
4161 spi_acpi_controller_match);
4162 if (!dev)
4163 return NULL;
4164
4165 return container_of(dev, struct spi_controller, dev);
4166 }
4167
acpi_spi_find_device_by_adev(struct acpi_device * adev)4168 static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
4169 {
4170 struct device *dev;
4171
4172 dev = bus_find_device_by_acpi_dev(&spi_bus_type, adev);
4173 return to_spi_device(dev);
4174 }
4175
acpi_spi_notify(struct notifier_block * nb,unsigned long value,void * arg)4176 static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
4177 void *arg)
4178 {
4179 struct acpi_device *adev = arg;
4180 struct spi_controller *ctlr;
4181 struct spi_device *spi;
4182
4183 switch (value) {
4184 case ACPI_RECONFIG_DEVICE_ADD:
4185 ctlr = acpi_spi_find_controller_by_adev(adev->parent);
4186 if (!ctlr)
4187 break;
4188
4189 acpi_register_spi_device(ctlr, adev);
4190 put_device(&ctlr->dev);
4191 break;
4192 case ACPI_RECONFIG_DEVICE_REMOVE:
4193 if (!acpi_device_enumerated(adev))
4194 break;
4195
4196 spi = acpi_spi_find_device_by_adev(adev);
4197 if (!spi)
4198 break;
4199
4200 spi_unregister_device(spi);
4201 put_device(&spi->dev);
4202 break;
4203 }
4204
4205 return NOTIFY_OK;
4206 }
4207
4208 static struct notifier_block spi_acpi_notifier = {
4209 .notifier_call = acpi_spi_notify,
4210 };
4211 #else
4212 extern struct notifier_block spi_acpi_notifier;
4213 #endif
4214
spi_init(void)4215 static int __init spi_init(void)
4216 {
4217 int status;
4218
4219 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
4220 if (!buf) {
4221 status = -ENOMEM;
4222 goto err0;
4223 }
4224
4225 status = bus_register(&spi_bus_type);
4226 if (status < 0)
4227 goto err1;
4228
4229 status = class_register(&spi_master_class);
4230 if (status < 0)
4231 goto err2;
4232
4233 if (IS_ENABLED(CONFIG_SPI_SLAVE)) {
4234 status = class_register(&spi_slave_class);
4235 if (status < 0)
4236 goto err3;
4237 }
4238
4239 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
4240 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
4241 if (IS_ENABLED(CONFIG_ACPI))
4242 WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
4243
4244 return 0;
4245
4246 err3:
4247 class_unregister(&spi_master_class);
4248 err2:
4249 bus_unregister(&spi_bus_type);
4250 err1:
4251 kfree(buf);
4252 buf = NULL;
4253 err0:
4254 return status;
4255 }
4256
4257 /* board_info is normally registered in arch_initcall(),
4258 * but even essential drivers wait till later
4259 *
4260 * REVISIT only boardinfo really needs static linking. the rest (device and
4261 * driver registration) _could_ be dynamically linked (modular) ... costs
4262 * include needing to have boardinfo data structures be much more public.
4263 */
4264 postcore_initcall(spi_init);
4265