1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Error Location Module
4 *
5 * Copyright (C) 2012 Texas Instruments Incorporated - https://www.ti.com/
6 */
7
8 #define DRIVER_NAME "omap-elm"
9
10 #include <linux/platform_device.h>
11 #include <linux/module.h>
12 #include <linux/interrupt.h>
13 #include <linux/io.h>
14 #include <linux/of.h>
15 #include <linux/sched.h>
16 #include <linux/pm_runtime.h>
17 #include <linux/platform_data/elm.h>
18
19 #define ELM_SYSCONFIG 0x010
20 #define ELM_IRQSTATUS 0x018
21 #define ELM_IRQENABLE 0x01c
22 #define ELM_LOCATION_CONFIG 0x020
23 #define ELM_PAGE_CTRL 0x080
24 #define ELM_SYNDROME_FRAGMENT_0 0x400
25 #define ELM_SYNDROME_FRAGMENT_1 0x404
26 #define ELM_SYNDROME_FRAGMENT_2 0x408
27 #define ELM_SYNDROME_FRAGMENT_3 0x40c
28 #define ELM_SYNDROME_FRAGMENT_4 0x410
29 #define ELM_SYNDROME_FRAGMENT_5 0x414
30 #define ELM_SYNDROME_FRAGMENT_6 0x418
31 #define ELM_LOCATION_STATUS 0x800
32 #define ELM_ERROR_LOCATION_0 0x880
33
34 /* ELM Interrupt Status Register */
35 #define INTR_STATUS_PAGE_VALID BIT(8)
36
37 /* ELM Interrupt Enable Register */
38 #define INTR_EN_PAGE_MASK BIT(8)
39
40 /* ELM Location Configuration Register */
41 #define ECC_BCH_LEVEL_MASK 0x3
42
43 /* ELM syndrome */
44 #define ELM_SYNDROME_VALID BIT(16)
45
46 /* ELM_LOCATION_STATUS Register */
47 #define ECC_CORRECTABLE_MASK BIT(8)
48 #define ECC_NB_ERRORS_MASK 0x1f
49
50 /* ELM_ERROR_LOCATION_0-15 Registers */
51 #define ECC_ERROR_LOCATION_MASK 0x1fff
52
53 #define ELM_ECC_SIZE 0x7ff
54
55 #define SYNDROME_FRAGMENT_REG_SIZE 0x40
56 #define ERROR_LOCATION_SIZE 0x100
57
58 struct elm_registers {
59 u32 elm_irqenable;
60 u32 elm_sysconfig;
61 u32 elm_location_config;
62 u32 elm_page_ctrl;
63 u32 elm_syndrome_fragment_6[ERROR_VECTOR_MAX];
64 u32 elm_syndrome_fragment_5[ERROR_VECTOR_MAX];
65 u32 elm_syndrome_fragment_4[ERROR_VECTOR_MAX];
66 u32 elm_syndrome_fragment_3[ERROR_VECTOR_MAX];
67 u32 elm_syndrome_fragment_2[ERROR_VECTOR_MAX];
68 u32 elm_syndrome_fragment_1[ERROR_VECTOR_MAX];
69 u32 elm_syndrome_fragment_0[ERROR_VECTOR_MAX];
70 };
71
72 struct elm_info {
73 struct device *dev;
74 void __iomem *elm_base;
75 struct completion elm_completion;
76 struct list_head list;
77 enum bch_ecc bch_type;
78 struct elm_registers elm_regs;
79 int ecc_steps;
80 int ecc_syndrome_size;
81 };
82
83 static LIST_HEAD(elm_devices);
84
elm_write_reg(struct elm_info * info,int offset,u32 val)85 static void elm_write_reg(struct elm_info *info, int offset, u32 val)
86 {
87 writel(val, info->elm_base + offset);
88 }
89
elm_read_reg(struct elm_info * info,int offset)90 static u32 elm_read_reg(struct elm_info *info, int offset)
91 {
92 return readl(info->elm_base + offset);
93 }
94
95 /**
96 * elm_config - Configure ELM module
97 * @dev: ELM device
98 * @bch_type: Type of BCH ecc
99 * @ecc_steps: ECC steps to assign to config
100 * @ecc_step_size: ECC step size to assign to config
101 * @ecc_syndrome_size: ECC syndrome size to assign to config
102 */
elm_config(struct device * dev,enum bch_ecc bch_type,int ecc_steps,int ecc_step_size,int ecc_syndrome_size)103 int elm_config(struct device *dev, enum bch_ecc bch_type,
104 int ecc_steps, int ecc_step_size, int ecc_syndrome_size)
105 {
106 u32 reg_val;
107 struct elm_info *info = dev_get_drvdata(dev);
108
109 if (!info) {
110 dev_err(dev, "Unable to configure elm - device not probed?\n");
111 return -EPROBE_DEFER;
112 }
113 /* ELM cannot detect ECC errors for chunks > 1KB */
114 if (ecc_step_size > ((ELM_ECC_SIZE + 1) / 2)) {
115 dev_err(dev, "unsupported config ecc-size=%d\n", ecc_step_size);
116 return -EINVAL;
117 }
118 /* ELM support 8 error syndrome process */
119 if (ecc_steps > ERROR_VECTOR_MAX) {
120 dev_err(dev, "unsupported config ecc-step=%d\n", ecc_steps);
121 return -EINVAL;
122 }
123
124 reg_val = (bch_type & ECC_BCH_LEVEL_MASK) | (ELM_ECC_SIZE << 16);
125 elm_write_reg(info, ELM_LOCATION_CONFIG, reg_val);
126 info->bch_type = bch_type;
127 info->ecc_steps = ecc_steps;
128 info->ecc_syndrome_size = ecc_syndrome_size;
129
130 return 0;
131 }
132 EXPORT_SYMBOL(elm_config);
133
134 /**
135 * elm_configure_page_mode - Enable/Disable page mode
136 * @info: elm info
137 * @index: index number of syndrome fragment vector
138 * @enable: enable/disable flag for page mode
139 *
140 * Enable page mode for syndrome fragment index
141 */
elm_configure_page_mode(struct elm_info * info,int index,bool enable)142 static void elm_configure_page_mode(struct elm_info *info, int index,
143 bool enable)
144 {
145 u32 reg_val;
146
147 reg_val = elm_read_reg(info, ELM_PAGE_CTRL);
148 if (enable)
149 reg_val |= BIT(index); /* enable page mode */
150 else
151 reg_val &= ~BIT(index); /* disable page mode */
152
153 elm_write_reg(info, ELM_PAGE_CTRL, reg_val);
154 }
155
156 /**
157 * elm_load_syndrome - Load ELM syndrome reg
158 * @info: elm info
159 * @err_vec: elm error vectors
160 * @ecc: buffer with calculated ecc
161 *
162 * Load syndrome fragment registers with calculated ecc in reverse order.
163 */
elm_load_syndrome(struct elm_info * info,struct elm_errorvec * err_vec,u8 * ecc)164 static void elm_load_syndrome(struct elm_info *info,
165 struct elm_errorvec *err_vec, u8 *ecc)
166 {
167 int i, offset;
168 u32 val;
169
170 for (i = 0; i < info->ecc_steps; i++) {
171
172 /* Check error reported */
173 if (err_vec[i].error_reported) {
174 elm_configure_page_mode(info, i, true);
175 offset = ELM_SYNDROME_FRAGMENT_0 +
176 SYNDROME_FRAGMENT_REG_SIZE * i;
177 switch (info->bch_type) {
178 case BCH8_ECC:
179 /* syndrome fragment 0 = ecc[9-12B] */
180 val = cpu_to_be32(*(u32 *) &ecc[9]);
181 elm_write_reg(info, offset, val);
182
183 /* syndrome fragment 1 = ecc[5-8B] */
184 offset += 4;
185 val = cpu_to_be32(*(u32 *) &ecc[5]);
186 elm_write_reg(info, offset, val);
187
188 /* syndrome fragment 2 = ecc[1-4B] */
189 offset += 4;
190 val = cpu_to_be32(*(u32 *) &ecc[1]);
191 elm_write_reg(info, offset, val);
192
193 /* syndrome fragment 3 = ecc[0B] */
194 offset += 4;
195 val = ecc[0];
196 elm_write_reg(info, offset, val);
197 break;
198 case BCH4_ECC:
199 /* syndrome fragment 0 = ecc[20-52b] bits */
200 val = (cpu_to_be32(*(u32 *) &ecc[3]) >> 4) |
201 ((ecc[2] & 0xf) << 28);
202 elm_write_reg(info, offset, val);
203
204 /* syndrome fragment 1 = ecc[0-20b] bits */
205 offset += 4;
206 val = cpu_to_be32(*(u32 *) &ecc[0]) >> 12;
207 elm_write_reg(info, offset, val);
208 break;
209 case BCH16_ECC:
210 val = cpu_to_be32(*(u32 *) &ecc[22]);
211 elm_write_reg(info, offset, val);
212 offset += 4;
213 val = cpu_to_be32(*(u32 *) &ecc[18]);
214 elm_write_reg(info, offset, val);
215 offset += 4;
216 val = cpu_to_be32(*(u32 *) &ecc[14]);
217 elm_write_reg(info, offset, val);
218 offset += 4;
219 val = cpu_to_be32(*(u32 *) &ecc[10]);
220 elm_write_reg(info, offset, val);
221 offset += 4;
222 val = cpu_to_be32(*(u32 *) &ecc[6]);
223 elm_write_reg(info, offset, val);
224 offset += 4;
225 val = cpu_to_be32(*(u32 *) &ecc[2]);
226 elm_write_reg(info, offset, val);
227 offset += 4;
228 val = cpu_to_be32(*(u32 *) &ecc[0]) >> 16;
229 elm_write_reg(info, offset, val);
230 break;
231 default:
232 pr_err("invalid config bch_type\n");
233 }
234 }
235
236 /* Update ecc pointer with ecc byte size */
237 ecc += info->ecc_syndrome_size;
238 }
239 }
240
241 /**
242 * elm_start_processing - start elm syndrome processing
243 * @info: elm info
244 * @err_vec: elm error vectors
245 *
246 * Set syndrome valid bit for syndrome fragment registers for which
247 * elm syndrome fragment registers are loaded. This enables elm module
248 * to start processing syndrome vectors.
249 */
elm_start_processing(struct elm_info * info,struct elm_errorvec * err_vec)250 static void elm_start_processing(struct elm_info *info,
251 struct elm_errorvec *err_vec)
252 {
253 int i, offset;
254 u32 reg_val;
255
256 /*
257 * Set syndrome vector valid, so that ELM module
258 * will process it for vectors error is reported
259 */
260 for (i = 0; i < info->ecc_steps; i++) {
261 if (err_vec[i].error_reported) {
262 offset = ELM_SYNDROME_FRAGMENT_6 +
263 SYNDROME_FRAGMENT_REG_SIZE * i;
264 reg_val = elm_read_reg(info, offset);
265 reg_val |= ELM_SYNDROME_VALID;
266 elm_write_reg(info, offset, reg_val);
267 }
268 }
269 }
270
271 /**
272 * elm_error_correction - locate correctable error position
273 * @info: elm info
274 * @err_vec: elm error vectors
275 *
276 * On completion of processing by elm module, error location status
277 * register updated with correctable/uncorrectable error information.
278 * In case of correctable errors, number of errors located from
279 * elm location status register & read the positions from
280 * elm error location register.
281 */
elm_error_correction(struct elm_info * info,struct elm_errorvec * err_vec)282 static void elm_error_correction(struct elm_info *info,
283 struct elm_errorvec *err_vec)
284 {
285 int i, j, errors = 0;
286 int offset;
287 u32 reg_val;
288
289 for (i = 0; i < info->ecc_steps; i++) {
290
291 /* Check error reported */
292 if (err_vec[i].error_reported) {
293 offset = ELM_LOCATION_STATUS + ERROR_LOCATION_SIZE * i;
294 reg_val = elm_read_reg(info, offset);
295
296 /* Check correctable error or not */
297 if (reg_val & ECC_CORRECTABLE_MASK) {
298 offset = ELM_ERROR_LOCATION_0 +
299 ERROR_LOCATION_SIZE * i;
300
301 /* Read count of correctable errors */
302 err_vec[i].error_count = reg_val &
303 ECC_NB_ERRORS_MASK;
304
305 /* Update the error locations in error vector */
306 for (j = 0; j < err_vec[i].error_count; j++) {
307
308 reg_val = elm_read_reg(info, offset);
309 err_vec[i].error_loc[j] = reg_val &
310 ECC_ERROR_LOCATION_MASK;
311
312 /* Update error location register */
313 offset += 4;
314 }
315
316 errors += err_vec[i].error_count;
317 } else {
318 err_vec[i].error_uncorrectable = true;
319 }
320
321 /* Clearing interrupts for processed error vectors */
322 elm_write_reg(info, ELM_IRQSTATUS, BIT(i));
323
324 /* Disable page mode */
325 elm_configure_page_mode(info, i, false);
326 }
327 }
328 }
329
330 /**
331 * elm_decode_bch_error_page - Locate error position
332 * @dev: device pointer
333 * @ecc_calc: calculated ECC bytes from GPMC
334 * @err_vec: elm error vectors
335 *
336 * Called with one or more error reported vectors & vectors with
337 * error reported is updated in err_vec[].error_reported
338 */
elm_decode_bch_error_page(struct device * dev,u8 * ecc_calc,struct elm_errorvec * err_vec)339 void elm_decode_bch_error_page(struct device *dev, u8 *ecc_calc,
340 struct elm_errorvec *err_vec)
341 {
342 struct elm_info *info = dev_get_drvdata(dev);
343 u32 reg_val;
344
345 /* Enable page mode interrupt */
346 reg_val = elm_read_reg(info, ELM_IRQSTATUS);
347 elm_write_reg(info, ELM_IRQSTATUS, reg_val & INTR_STATUS_PAGE_VALID);
348 elm_write_reg(info, ELM_IRQENABLE, INTR_EN_PAGE_MASK);
349
350 /* Load valid ecc byte to syndrome fragment register */
351 elm_load_syndrome(info, err_vec, ecc_calc);
352
353 /* Enable syndrome processing for which syndrome fragment is updated */
354 elm_start_processing(info, err_vec);
355
356 /* Wait for ELM module to finish locating error correction */
357 wait_for_completion(&info->elm_completion);
358
359 /* Disable page mode interrupt */
360 reg_val = elm_read_reg(info, ELM_IRQENABLE);
361 elm_write_reg(info, ELM_IRQENABLE, reg_val & ~INTR_EN_PAGE_MASK);
362 elm_error_correction(info, err_vec);
363 }
364 EXPORT_SYMBOL(elm_decode_bch_error_page);
365
elm_isr(int this_irq,void * dev_id)366 static irqreturn_t elm_isr(int this_irq, void *dev_id)
367 {
368 u32 reg_val;
369 struct elm_info *info = dev_id;
370
371 reg_val = elm_read_reg(info, ELM_IRQSTATUS);
372
373 /* All error vectors processed */
374 if (reg_val & INTR_STATUS_PAGE_VALID) {
375 elm_write_reg(info, ELM_IRQSTATUS,
376 reg_val & INTR_STATUS_PAGE_VALID);
377 complete(&info->elm_completion);
378 return IRQ_HANDLED;
379 }
380
381 return IRQ_NONE;
382 }
383
elm_probe(struct platform_device * pdev)384 static int elm_probe(struct platform_device *pdev)
385 {
386 int ret = 0;
387 struct resource *res, *irq;
388 struct elm_info *info;
389
390 info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
391 if (!info)
392 return -ENOMEM;
393
394 info->dev = &pdev->dev;
395
396 irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
397 if (!irq) {
398 dev_err(&pdev->dev, "no irq resource defined\n");
399 return -ENODEV;
400 }
401
402 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
403 info->elm_base = devm_ioremap_resource(&pdev->dev, res);
404 if (IS_ERR(info->elm_base))
405 return PTR_ERR(info->elm_base);
406
407 ret = devm_request_irq(&pdev->dev, irq->start, elm_isr, 0,
408 pdev->name, info);
409 if (ret) {
410 dev_err(&pdev->dev, "failure requesting %pr\n", irq);
411 return ret;
412 }
413
414 pm_runtime_enable(&pdev->dev);
415 if (pm_runtime_get_sync(&pdev->dev) < 0) {
416 ret = -EINVAL;
417 pm_runtime_put_sync(&pdev->dev);
418 pm_runtime_disable(&pdev->dev);
419 dev_err(&pdev->dev, "can't enable clock\n");
420 return ret;
421 }
422
423 init_completion(&info->elm_completion);
424 INIT_LIST_HEAD(&info->list);
425 list_add(&info->list, &elm_devices);
426 platform_set_drvdata(pdev, info);
427 return ret;
428 }
429
elm_remove(struct platform_device * pdev)430 static int elm_remove(struct platform_device *pdev)
431 {
432 pm_runtime_put_sync(&pdev->dev);
433 pm_runtime_disable(&pdev->dev);
434 return 0;
435 }
436
437 #ifdef CONFIG_PM_SLEEP
438 /*
439 * elm_context_save
440 * saves ELM configurations to preserve them across Hardware powered-down
441 */
elm_context_save(struct elm_info * info)442 static int elm_context_save(struct elm_info *info)
443 {
444 struct elm_registers *regs = &info->elm_regs;
445 enum bch_ecc bch_type = info->bch_type;
446 u32 offset = 0, i;
447
448 regs->elm_irqenable = elm_read_reg(info, ELM_IRQENABLE);
449 regs->elm_sysconfig = elm_read_reg(info, ELM_SYSCONFIG);
450 regs->elm_location_config = elm_read_reg(info, ELM_LOCATION_CONFIG);
451 regs->elm_page_ctrl = elm_read_reg(info, ELM_PAGE_CTRL);
452 for (i = 0; i < ERROR_VECTOR_MAX; i++) {
453 offset = i * SYNDROME_FRAGMENT_REG_SIZE;
454 switch (bch_type) {
455 case BCH16_ECC:
456 regs->elm_syndrome_fragment_6[i] = elm_read_reg(info,
457 ELM_SYNDROME_FRAGMENT_6 + offset);
458 regs->elm_syndrome_fragment_5[i] = elm_read_reg(info,
459 ELM_SYNDROME_FRAGMENT_5 + offset);
460 regs->elm_syndrome_fragment_4[i] = elm_read_reg(info,
461 ELM_SYNDROME_FRAGMENT_4 + offset);
462 fallthrough;
463 case BCH8_ECC:
464 regs->elm_syndrome_fragment_3[i] = elm_read_reg(info,
465 ELM_SYNDROME_FRAGMENT_3 + offset);
466 regs->elm_syndrome_fragment_2[i] = elm_read_reg(info,
467 ELM_SYNDROME_FRAGMENT_2 + offset);
468 fallthrough;
469 case BCH4_ECC:
470 regs->elm_syndrome_fragment_1[i] = elm_read_reg(info,
471 ELM_SYNDROME_FRAGMENT_1 + offset);
472 regs->elm_syndrome_fragment_0[i] = elm_read_reg(info,
473 ELM_SYNDROME_FRAGMENT_0 + offset);
474 break;
475 default:
476 return -EINVAL;
477 }
478 /* ELM SYNDROME_VALID bit in SYNDROME_FRAGMENT_6[] needs
479 * to be saved for all BCH schemes*/
480 regs->elm_syndrome_fragment_6[i] = elm_read_reg(info,
481 ELM_SYNDROME_FRAGMENT_6 + offset);
482 }
483 return 0;
484 }
485
486 /*
487 * elm_context_restore
488 * writes configurations saved duing power-down back into ELM registers
489 */
elm_context_restore(struct elm_info * info)490 static int elm_context_restore(struct elm_info *info)
491 {
492 struct elm_registers *regs = &info->elm_regs;
493 enum bch_ecc bch_type = info->bch_type;
494 u32 offset = 0, i;
495
496 elm_write_reg(info, ELM_IRQENABLE, regs->elm_irqenable);
497 elm_write_reg(info, ELM_SYSCONFIG, regs->elm_sysconfig);
498 elm_write_reg(info, ELM_LOCATION_CONFIG, regs->elm_location_config);
499 elm_write_reg(info, ELM_PAGE_CTRL, regs->elm_page_ctrl);
500 for (i = 0; i < ERROR_VECTOR_MAX; i++) {
501 offset = i * SYNDROME_FRAGMENT_REG_SIZE;
502 switch (bch_type) {
503 case BCH16_ECC:
504 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_6 + offset,
505 regs->elm_syndrome_fragment_6[i]);
506 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_5 + offset,
507 regs->elm_syndrome_fragment_5[i]);
508 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_4 + offset,
509 regs->elm_syndrome_fragment_4[i]);
510 fallthrough;
511 case BCH8_ECC:
512 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_3 + offset,
513 regs->elm_syndrome_fragment_3[i]);
514 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_2 + offset,
515 regs->elm_syndrome_fragment_2[i]);
516 fallthrough;
517 case BCH4_ECC:
518 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_1 + offset,
519 regs->elm_syndrome_fragment_1[i]);
520 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_0 + offset,
521 regs->elm_syndrome_fragment_0[i]);
522 break;
523 default:
524 return -EINVAL;
525 }
526 /* ELM_SYNDROME_VALID bit to be set in last to trigger FSM */
527 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_6 + offset,
528 regs->elm_syndrome_fragment_6[i] &
529 ELM_SYNDROME_VALID);
530 }
531 return 0;
532 }
533
elm_suspend(struct device * dev)534 static int elm_suspend(struct device *dev)
535 {
536 struct elm_info *info = dev_get_drvdata(dev);
537 elm_context_save(info);
538 pm_runtime_put_sync(dev);
539 return 0;
540 }
541
elm_resume(struct device * dev)542 static int elm_resume(struct device *dev)
543 {
544 struct elm_info *info = dev_get_drvdata(dev);
545 pm_runtime_get_sync(dev);
546 elm_context_restore(info);
547 return 0;
548 }
549 #endif
550
551 static SIMPLE_DEV_PM_OPS(elm_pm_ops, elm_suspend, elm_resume);
552
553 #ifdef CONFIG_OF
554 static const struct of_device_id elm_of_match[] = {
555 { .compatible = "ti,am3352-elm" },
556 {},
557 };
558 MODULE_DEVICE_TABLE(of, elm_of_match);
559 #endif
560
561 static struct platform_driver elm_driver = {
562 .driver = {
563 .name = DRIVER_NAME,
564 .of_match_table = of_match_ptr(elm_of_match),
565 .pm = &elm_pm_ops,
566 },
567 .probe = elm_probe,
568 .remove = elm_remove,
569 };
570
571 module_platform_driver(elm_driver);
572
573 MODULE_DESCRIPTION("ELM driver for BCH error correction");
574 MODULE_AUTHOR("Texas Instruments");
575 MODULE_ALIAS("platform:" DRIVER_NAME);
576 MODULE_LICENSE("GPL v2");
577