1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * ispstat.c
4  *
5  * TI OMAP3 ISP - Statistics core
6  *
7  * Copyright (C) 2010 Nokia Corporation
8  * Copyright (C) 2009 Texas Instruments, Inc
9  *
10  * Contacts: David Cohen <dacohen@gmail.com>
11  *	     Laurent Pinchart <laurent.pinchart@ideasonboard.com>
12  *	     Sakari Ailus <sakari.ailus@iki.fi>
13  */
14 
15 #include <linux/dma-mapping.h>
16 #include <linux/slab.h>
17 #include <linux/timekeeping.h>
18 #include <linux/uaccess.h>
19 
20 #include "isp.h"
21 
22 #define ISP_STAT_USES_DMAENGINE(stat)	((stat)->dma_ch != NULL)
23 
24 /*
25  * MAGIC_SIZE must always be the greatest common divisor of
26  * AEWB_PACKET_SIZE and AF_PAXEL_SIZE.
27  */
28 #define MAGIC_SIZE		16
29 #define MAGIC_NUM		0x55
30 
31 /* HACK: AF module seems to be writing one more paxel data than it should. */
32 #define AF_EXTRA_DATA		OMAP3ISP_AF_PAXEL_SIZE
33 
34 /*
35  * HACK: H3A modules go to an invalid state after have a SBL overflow. It makes
36  * the next buffer to start to be written in the same point where the overflow
37  * occurred instead of the configured address. The only known way to make it to
38  * go back to a valid state is having a valid buffer processing. Of course it
39  * requires at least a doubled buffer size to avoid an access to invalid memory
40  * region. But it does not fix everything. It may happen more than one
41  * consecutive SBL overflows. In that case, it might be unpredictable how many
42  * buffers the allocated memory should fit. For that case, a recover
43  * configuration was created. It produces the minimum buffer size for each H3A
44  * module and decrease the change for more SBL overflows. This recover state
45  * will be enabled every time a SBL overflow occur. As the output buffer size
46  * isn't big, it's possible to have an extra size able to fit many recover
47  * buffers making it extreamily unlikely to have an access to invalid memory
48  * region.
49  */
50 #define NUM_H3A_RECOVER_BUFS	10
51 
52 /*
53  * HACK: Because of HW issues the generic layer sometimes need to have
54  * different behaviour for different statistic modules.
55  */
56 #define IS_H3A_AF(stat)		((stat) == &(stat)->isp->isp_af)
57 #define IS_H3A_AEWB(stat)	((stat) == &(stat)->isp->isp_aewb)
58 #define IS_H3A(stat)		(IS_H3A_AF(stat) || IS_H3A_AEWB(stat))
59 
60 static void __isp_stat_buf_sync_magic(struct ispstat *stat,
61 				      struct ispstat_buffer *buf,
62 				      u32 buf_size, enum dma_data_direction dir,
63 				      void (*dma_sync)(struct device *,
64 					dma_addr_t, unsigned long, size_t,
65 					enum dma_data_direction))
66 {
67 	/* Sync the initial and final magic words. */
68 	dma_sync(stat->isp->dev, buf->dma_addr, 0, MAGIC_SIZE, dir);
69 	dma_sync(stat->isp->dev, buf->dma_addr + (buf_size & PAGE_MASK),
70 		 buf_size & ~PAGE_MASK, MAGIC_SIZE, dir);
71 }
72 
73 static void isp_stat_buf_sync_magic_for_device(struct ispstat *stat,
74 					       struct ispstat_buffer *buf,
75 					       u32 buf_size,
76 					       enum dma_data_direction dir)
77 {
78 	if (ISP_STAT_USES_DMAENGINE(stat))
79 		return;
80 
81 	__isp_stat_buf_sync_magic(stat, buf, buf_size, dir,
82 				  dma_sync_single_range_for_device);
83 }
84 
85 static void isp_stat_buf_sync_magic_for_cpu(struct ispstat *stat,
86 					    struct ispstat_buffer *buf,
87 					    u32 buf_size,
88 					    enum dma_data_direction dir)
89 {
90 	if (ISP_STAT_USES_DMAENGINE(stat))
91 		return;
92 
93 	__isp_stat_buf_sync_magic(stat, buf, buf_size, dir,
94 				  dma_sync_single_range_for_cpu);
95 }
96 
97 static int isp_stat_buf_check_magic(struct ispstat *stat,
98 				    struct ispstat_buffer *buf)
99 {
100 	const u32 buf_size = IS_H3A_AF(stat) ?
101 			     buf->buf_size + AF_EXTRA_DATA : buf->buf_size;
102 	u8 *w;
103 	u8 *end;
104 	int ret = -EINVAL;
105 
106 	isp_stat_buf_sync_magic_for_cpu(stat, buf, buf_size, DMA_FROM_DEVICE);
107 
108 	/* Checking initial magic numbers. They shouldn't be here anymore. */
109 	for (w = buf->virt_addr, end = w + MAGIC_SIZE; w < end; w++)
110 		if (likely(*w != MAGIC_NUM))
111 			ret = 0;
112 
113 	if (ret) {
114 		dev_dbg(stat->isp->dev,
115 			"%s: beginning magic check does not match.\n",
116 			stat->subdev.name);
117 		return ret;
118 	}
119 
120 	/* Checking magic numbers at the end. They must be still here. */
121 	for (w = buf->virt_addr + buf_size, end = w + MAGIC_SIZE;
122 	     w < end; w++) {
123 		if (unlikely(*w != MAGIC_NUM)) {
124 			dev_dbg(stat->isp->dev,
125 				"%s: ending magic check does not match.\n",
126 				stat->subdev.name);
127 			return -EINVAL;
128 		}
129 	}
130 
131 	isp_stat_buf_sync_magic_for_device(stat, buf, buf_size,
132 					   DMA_FROM_DEVICE);
133 
134 	return 0;
135 }
136 
137 static void isp_stat_buf_insert_magic(struct ispstat *stat,
138 				      struct ispstat_buffer *buf)
139 {
140 	const u32 buf_size = IS_H3A_AF(stat) ?
141 			     stat->buf_size + AF_EXTRA_DATA : stat->buf_size;
142 
143 	isp_stat_buf_sync_magic_for_cpu(stat, buf, buf_size, DMA_FROM_DEVICE);
144 
145 	/*
146 	 * Inserting MAGIC_NUM at the beginning and end of the buffer.
147 	 * buf->buf_size is set only after the buffer is queued. For now the
148 	 * right buf_size for the current configuration is pointed by
149 	 * stat->buf_size.
150 	 */
151 	memset(buf->virt_addr, MAGIC_NUM, MAGIC_SIZE);
152 	memset(buf->virt_addr + buf_size, MAGIC_NUM, MAGIC_SIZE);
153 
154 	isp_stat_buf_sync_magic_for_device(stat, buf, buf_size,
155 					   DMA_BIDIRECTIONAL);
156 }
157 
158 static void isp_stat_buf_sync_for_device(struct ispstat *stat,
159 					 struct ispstat_buffer *buf)
160 {
161 	if (ISP_STAT_USES_DMAENGINE(stat))
162 		return;
163 
164 	dma_sync_sg_for_device(stat->isp->dev, buf->sgt.sgl,
165 			       buf->sgt.nents, DMA_FROM_DEVICE);
166 }
167 
168 static void isp_stat_buf_sync_for_cpu(struct ispstat *stat,
169 				      struct ispstat_buffer *buf)
170 {
171 	if (ISP_STAT_USES_DMAENGINE(stat))
172 		return;
173 
174 	dma_sync_sg_for_cpu(stat->isp->dev, buf->sgt.sgl,
175 			    buf->sgt.nents, DMA_FROM_DEVICE);
176 }
177 
178 static void isp_stat_buf_clear(struct ispstat *stat)
179 {
180 	int i;
181 
182 	for (i = 0; i < STAT_MAX_BUFS; i++)
183 		stat->buf[i].empty = 1;
184 }
185 
186 static struct ispstat_buffer *
187 __isp_stat_buf_find(struct ispstat *stat, int look_empty)
188 {
189 	struct ispstat_buffer *found = NULL;
190 	int i;
191 
192 	for (i = 0; i < STAT_MAX_BUFS; i++) {
193 		struct ispstat_buffer *curr = &stat->buf[i];
194 
195 		/*
196 		 * Don't select the buffer which is being copied to
197 		 * userspace or used by the module.
198 		 */
199 		if (curr == stat->locked_buf || curr == stat->active_buf)
200 			continue;
201 
202 		/* Don't select uninitialised buffers if it's not required */
203 		if (!look_empty && curr->empty)
204 			continue;
205 
206 		/* Pick uninitialised buffer over anything else if look_empty */
207 		if (curr->empty) {
208 			found = curr;
209 			break;
210 		}
211 
212 		/* Choose the oldest buffer */
213 		if (!found ||
214 		    (s32)curr->frame_number - (s32)found->frame_number < 0)
215 			found = curr;
216 	}
217 
218 	return found;
219 }
220 
221 static inline struct ispstat_buffer *
222 isp_stat_buf_find_oldest(struct ispstat *stat)
223 {
224 	return __isp_stat_buf_find(stat, 0);
225 }
226 
227 static inline struct ispstat_buffer *
228 isp_stat_buf_find_oldest_or_empty(struct ispstat *stat)
229 {
230 	return __isp_stat_buf_find(stat, 1);
231 }
232 
233 static int isp_stat_buf_queue(struct ispstat *stat)
234 {
235 	if (!stat->active_buf)
236 		return STAT_NO_BUF;
237 
238 	ktime_get_ts64(&stat->active_buf->ts);
239 
240 	stat->active_buf->buf_size = stat->buf_size;
241 	if (isp_stat_buf_check_magic(stat, stat->active_buf)) {
242 		dev_dbg(stat->isp->dev, "%s: data wasn't properly written.\n",
243 			stat->subdev.name);
244 		return STAT_NO_BUF;
245 	}
246 	stat->active_buf->config_counter = stat->config_counter;
247 	stat->active_buf->frame_number = stat->frame_number;
248 	stat->active_buf->empty = 0;
249 	stat->active_buf = NULL;
250 
251 	return STAT_BUF_DONE;
252 }
253 
254 /* Get next free buffer to write the statistics to and mark it active. */
255 static void isp_stat_buf_next(struct ispstat *stat)
256 {
257 	if (unlikely(stat->active_buf))
258 		/* Overwriting unused active buffer */
259 		dev_dbg(stat->isp->dev,
260 			"%s: new buffer requested without queuing active one.\n",
261 			stat->subdev.name);
262 	else
263 		stat->active_buf = isp_stat_buf_find_oldest_or_empty(stat);
264 }
265 
266 static void isp_stat_buf_release(struct ispstat *stat)
267 {
268 	unsigned long flags;
269 
270 	isp_stat_buf_sync_for_device(stat, stat->locked_buf);
271 	spin_lock_irqsave(&stat->isp->stat_lock, flags);
272 	stat->locked_buf = NULL;
273 	spin_unlock_irqrestore(&stat->isp->stat_lock, flags);
274 }
275 
276 /* Get buffer to userspace. */
277 static struct ispstat_buffer *isp_stat_buf_get(struct ispstat *stat,
278 					       struct omap3isp_stat_data *data)
279 {
280 	int rval = 0;
281 	unsigned long flags;
282 	struct ispstat_buffer *buf;
283 
284 	spin_lock_irqsave(&stat->isp->stat_lock, flags);
285 
286 	while (1) {
287 		buf = isp_stat_buf_find_oldest(stat);
288 		if (!buf) {
289 			spin_unlock_irqrestore(&stat->isp->stat_lock, flags);
290 			dev_dbg(stat->isp->dev, "%s: cannot find a buffer.\n",
291 				stat->subdev.name);
292 			return ERR_PTR(-EBUSY);
293 		}
294 		if (isp_stat_buf_check_magic(stat, buf)) {
295 			dev_dbg(stat->isp->dev,
296 				"%s: current buffer has corrupted data\n.",
297 				stat->subdev.name);
298 			/* Mark empty because it doesn't have valid data. */
299 			buf->empty = 1;
300 		} else {
301 			/* Buffer isn't corrupted. */
302 			break;
303 		}
304 	}
305 
306 	stat->locked_buf = buf;
307 
308 	spin_unlock_irqrestore(&stat->isp->stat_lock, flags);
309 
310 	if (buf->buf_size > data->buf_size) {
311 		dev_warn(stat->isp->dev,
312 			 "%s: userspace's buffer size is not enough.\n",
313 			 stat->subdev.name);
314 		isp_stat_buf_release(stat);
315 		return ERR_PTR(-EINVAL);
316 	}
317 
318 	isp_stat_buf_sync_for_cpu(stat, buf);
319 
320 	rval = copy_to_user(data->buf,
321 			    buf->virt_addr,
322 			    buf->buf_size);
323 
324 	if (rval) {
325 		dev_info(stat->isp->dev,
326 			 "%s: failed copying %d bytes of stat data\n",
327 			 stat->subdev.name, rval);
328 		buf = ERR_PTR(-EFAULT);
329 		isp_stat_buf_release(stat);
330 	}
331 
332 	return buf;
333 }
334 
335 static void isp_stat_bufs_free(struct ispstat *stat)
336 {
337 	struct device *dev = ISP_STAT_USES_DMAENGINE(stat)
338 			   ? NULL : stat->isp->dev;
339 	unsigned int i;
340 
341 	for (i = 0; i < STAT_MAX_BUFS; i++) {
342 		struct ispstat_buffer *buf = &stat->buf[i];
343 
344 		if (!buf->virt_addr)
345 			continue;
346 
347 		sg_free_table(&buf->sgt);
348 
349 		dma_free_coherent(dev, stat->buf_alloc_size, buf->virt_addr,
350 				  buf->dma_addr);
351 
352 		buf->dma_addr = 0;
353 		buf->virt_addr = NULL;
354 		buf->empty = 1;
355 	}
356 
357 	dev_dbg(stat->isp->dev, "%s: all buffers were freed.\n",
358 		stat->subdev.name);
359 
360 	stat->buf_alloc_size = 0;
361 	stat->active_buf = NULL;
362 }
363 
364 static int isp_stat_bufs_alloc_one(struct device *dev,
365 				   struct ispstat_buffer *buf,
366 				   unsigned int size)
367 {
368 	int ret;
369 
370 	buf->virt_addr = dma_alloc_coherent(dev, size, &buf->dma_addr,
371 					    GFP_KERNEL);
372 	if (!buf->virt_addr)
373 		return -ENOMEM;
374 
375 	ret = dma_get_sgtable(dev, &buf->sgt, buf->virt_addr, buf->dma_addr,
376 			      size);
377 	if (ret < 0) {
378 		dma_free_coherent(dev, size, buf->virt_addr, buf->dma_addr);
379 		buf->virt_addr = NULL;
380 		buf->dma_addr = 0;
381 		return ret;
382 	}
383 
384 	return 0;
385 }
386 
387 /*
388  * The device passed to the DMA API depends on whether the statistics block uses
389  * ISP DMA, external DMA or PIO to transfer data.
390  *
391  * The first case (for the AEWB and AF engines) passes the ISP device, resulting
392  * in the DMA buffers being mapped through the ISP IOMMU.
393  *
394  * The second case (for the histogram engine) should pass the DMA engine device.
395  * As that device isn't accessible through the OMAP DMA engine API the driver
396  * passes NULL instead, resulting in the buffers being mapped directly as
397  * physical pages.
398  *
399  * The third case (for the histogram engine) doesn't require any mapping. The
400  * buffers could be allocated with kmalloc/vmalloc, but we still use
401  * dma_alloc_coherent() for consistency purpose.
402  */
403 static int isp_stat_bufs_alloc(struct ispstat *stat, u32 size)
404 {
405 	struct device *dev = ISP_STAT_USES_DMAENGINE(stat)
406 			   ? NULL : stat->isp->dev;
407 	unsigned long flags;
408 	unsigned int i;
409 
410 	spin_lock_irqsave(&stat->isp->stat_lock, flags);
411 
412 	BUG_ON(stat->locked_buf != NULL);
413 
414 	/* Are the old buffers big enough? */
415 	if (stat->buf_alloc_size >= size) {
416 		spin_unlock_irqrestore(&stat->isp->stat_lock, flags);
417 		return 0;
418 	}
419 
420 	if (stat->state != ISPSTAT_DISABLED || stat->buf_processing) {
421 		dev_info(stat->isp->dev,
422 			 "%s: trying to allocate memory when busy\n",
423 			 stat->subdev.name);
424 		spin_unlock_irqrestore(&stat->isp->stat_lock, flags);
425 		return -EBUSY;
426 	}
427 
428 	spin_unlock_irqrestore(&stat->isp->stat_lock, flags);
429 
430 	isp_stat_bufs_free(stat);
431 
432 	stat->buf_alloc_size = size;
433 
434 	for (i = 0; i < STAT_MAX_BUFS; i++) {
435 		struct ispstat_buffer *buf = &stat->buf[i];
436 		int ret;
437 
438 		ret = isp_stat_bufs_alloc_one(dev, buf, size);
439 		if (ret < 0) {
440 			dev_err(stat->isp->dev,
441 				"%s: Failed to allocate DMA buffer %u\n",
442 				stat->subdev.name, i);
443 			isp_stat_bufs_free(stat);
444 			return ret;
445 		}
446 
447 		buf->empty = 1;
448 
449 		dev_dbg(stat->isp->dev,
450 			"%s: buffer[%u] allocated. dma=%pad virt=%p",
451 			stat->subdev.name, i, &buf->dma_addr, buf->virt_addr);
452 	}
453 
454 	return 0;
455 }
456 
457 static void isp_stat_queue_event(struct ispstat *stat, int err)
458 {
459 	struct video_device *vdev = stat->subdev.devnode;
460 	struct v4l2_event event;
461 	struct omap3isp_stat_event_status *status = (void *)event.u.data;
462 
463 	memset(&event, 0, sizeof(event));
464 	if (!err) {
465 		status->frame_number = stat->frame_number;
466 		status->config_counter = stat->config_counter;
467 	} else {
468 		status->buf_err = 1;
469 	}
470 	event.type = stat->event_type;
471 	v4l2_event_queue(vdev, &event);
472 }
473 
474 
475 /*
476  * omap3isp_stat_request_statistics - Request statistics.
477  * @data: Pointer to return statistics data.
478  *
479  * Returns 0 if successful.
480  */
481 int omap3isp_stat_request_statistics(struct ispstat *stat,
482 				     struct omap3isp_stat_data *data)
483 {
484 	struct ispstat_buffer *buf;
485 
486 	if (stat->state != ISPSTAT_ENABLED) {
487 		dev_dbg(stat->isp->dev, "%s: engine not enabled.\n",
488 			stat->subdev.name);
489 		return -EINVAL;
490 	}
491 
492 	mutex_lock(&stat->ioctl_lock);
493 	buf = isp_stat_buf_get(stat, data);
494 	if (IS_ERR(buf)) {
495 		mutex_unlock(&stat->ioctl_lock);
496 		return PTR_ERR(buf);
497 	}
498 
499 	data->ts.tv_sec = buf->ts.tv_sec;
500 	data->ts.tv_usec = buf->ts.tv_nsec / NSEC_PER_USEC;
501 	data->config_counter = buf->config_counter;
502 	data->frame_number = buf->frame_number;
503 	data->buf_size = buf->buf_size;
504 
505 	buf->empty = 1;
506 	isp_stat_buf_release(stat);
507 	mutex_unlock(&stat->ioctl_lock);
508 
509 	return 0;
510 }
511 
512 int omap3isp_stat_request_statistics_time32(struct ispstat *stat,
513 					struct omap3isp_stat_data_time32 *data)
514 {
515 	struct omap3isp_stat_data data64 = { };
516 	int ret;
517 
518 	ret = omap3isp_stat_request_statistics(stat, &data64);
519 	if (ret)
520 		return ret;
521 
522 	data->ts.tv_sec = data64.ts.tv_sec;
523 	data->ts.tv_usec = data64.ts.tv_usec;
524 	data->buf = (uintptr_t)data64.buf;
525 	memcpy(&data->frame, &data64.frame, sizeof(data->frame));
526 
527 	return 0;
528 }
529 
530 /*
531  * omap3isp_stat_config - Receives new statistic engine configuration.
532  * @new_conf: Pointer to config structure.
533  *
534  * Returns 0 if successful, -EINVAL if new_conf pointer is NULL, -ENOMEM if
535  * was unable to allocate memory for the buffer, or other errors if parameters
536  * are invalid.
537  */
538 int omap3isp_stat_config(struct ispstat *stat, void *new_conf)
539 {
540 	int ret;
541 	unsigned long irqflags;
542 	struct ispstat_generic_config *user_cfg = new_conf;
543 	u32 buf_size = user_cfg->buf_size;
544 
545 	mutex_lock(&stat->ioctl_lock);
546 
547 	dev_dbg(stat->isp->dev,
548 		"%s: configuring module with buffer size=0x%08lx\n",
549 		stat->subdev.name, (unsigned long)buf_size);
550 
551 	ret = stat->ops->validate_params(stat, new_conf);
552 	if (ret) {
553 		mutex_unlock(&stat->ioctl_lock);
554 		dev_dbg(stat->isp->dev, "%s: configuration values are invalid.\n",
555 			stat->subdev.name);
556 		return ret;
557 	}
558 
559 	if (buf_size != user_cfg->buf_size)
560 		dev_dbg(stat->isp->dev,
561 			"%s: driver has corrected buffer size request to 0x%08lx\n",
562 			stat->subdev.name,
563 			(unsigned long)user_cfg->buf_size);
564 
565 	/*
566 	 * Hack: H3A modules may need a doubled buffer size to avoid access
567 	 * to a invalid memory address after a SBL overflow.
568 	 * The buffer size is always PAGE_ALIGNED.
569 	 * Hack 2: MAGIC_SIZE is added to buf_size so a magic word can be
570 	 * inserted at the end to data integrity check purpose.
571 	 * Hack 3: AF module writes one paxel data more than it should, so
572 	 * the buffer allocation must consider it to avoid invalid memory
573 	 * access.
574 	 * Hack 4: H3A need to allocate extra space for the recover state.
575 	 */
576 	if (IS_H3A(stat)) {
577 		buf_size = user_cfg->buf_size * 2 + MAGIC_SIZE;
578 		if (IS_H3A_AF(stat))
579 			/*
580 			 * Adding one extra paxel data size for each recover
581 			 * buffer + 2 regular ones.
582 			 */
583 			buf_size += AF_EXTRA_DATA * (NUM_H3A_RECOVER_BUFS + 2);
584 		if (stat->recover_priv) {
585 			struct ispstat_generic_config *recover_cfg =
586 				stat->recover_priv;
587 			buf_size += recover_cfg->buf_size *
588 				    NUM_H3A_RECOVER_BUFS;
589 		}
590 		buf_size = PAGE_ALIGN(buf_size);
591 	} else { /* Histogram */
592 		buf_size = PAGE_ALIGN(user_cfg->buf_size + MAGIC_SIZE);
593 	}
594 
595 	ret = isp_stat_bufs_alloc(stat, buf_size);
596 	if (ret) {
597 		mutex_unlock(&stat->ioctl_lock);
598 		return ret;
599 	}
600 
601 	spin_lock_irqsave(&stat->isp->stat_lock, irqflags);
602 	stat->ops->set_params(stat, new_conf);
603 	spin_unlock_irqrestore(&stat->isp->stat_lock, irqflags);
604 
605 	/*
606 	 * Returning the right future config_counter for this setup, so
607 	 * userspace can *know* when it has been applied.
608 	 */
609 	user_cfg->config_counter = stat->config_counter + stat->inc_config;
610 
611 	/* Module has a valid configuration. */
612 	stat->configured = 1;
613 	dev_dbg(stat->isp->dev,
614 		"%s: module has been successfully configured.\n",
615 		stat->subdev.name);
616 
617 	mutex_unlock(&stat->ioctl_lock);
618 
619 	return 0;
620 }
621 
622 /*
623  * isp_stat_buf_process - Process statistic buffers.
624  * @buf_state: points out if buffer is ready to be processed. It's necessary
625  *	       because histogram needs to copy the data from internal memory
626  *	       before be able to process the buffer.
627  */
628 static int isp_stat_buf_process(struct ispstat *stat, int buf_state)
629 {
630 	int ret = STAT_NO_BUF;
631 
632 	if (!atomic_add_unless(&stat->buf_err, -1, 0) &&
633 	    buf_state == STAT_BUF_DONE && stat->state == ISPSTAT_ENABLED) {
634 		ret = isp_stat_buf_queue(stat);
635 		isp_stat_buf_next(stat);
636 	}
637 
638 	return ret;
639 }
640 
641 int omap3isp_stat_pcr_busy(struct ispstat *stat)
642 {
643 	return stat->ops->busy(stat);
644 }
645 
646 int omap3isp_stat_busy(struct ispstat *stat)
647 {
648 	return omap3isp_stat_pcr_busy(stat) | stat->buf_processing |
649 		(stat->state != ISPSTAT_DISABLED);
650 }
651 
652 /*
653  * isp_stat_pcr_enable - Disables/Enables statistic engines.
654  * @pcr_enable: 0/1 - Disables/Enables the engine.
655  *
656  * Must be called from ISP driver when the module is idle and synchronized
657  * with CCDC.
658  */
659 static void isp_stat_pcr_enable(struct ispstat *stat, u8 pcr_enable)
660 {
661 	if ((stat->state != ISPSTAT_ENABLING &&
662 	     stat->state != ISPSTAT_ENABLED) && pcr_enable)
663 		/* Userspace has disabled the module. Aborting. */
664 		return;
665 
666 	stat->ops->enable(stat, pcr_enable);
667 	if (stat->state == ISPSTAT_DISABLING && !pcr_enable)
668 		stat->state = ISPSTAT_DISABLED;
669 	else if (stat->state == ISPSTAT_ENABLING && pcr_enable)
670 		stat->state = ISPSTAT_ENABLED;
671 }
672 
673 void omap3isp_stat_suspend(struct ispstat *stat)
674 {
675 	unsigned long flags;
676 
677 	spin_lock_irqsave(&stat->isp->stat_lock, flags);
678 
679 	if (stat->state != ISPSTAT_DISABLED)
680 		stat->ops->enable(stat, 0);
681 	if (stat->state == ISPSTAT_ENABLED)
682 		stat->state = ISPSTAT_SUSPENDED;
683 
684 	spin_unlock_irqrestore(&stat->isp->stat_lock, flags);
685 }
686 
687 void omap3isp_stat_resume(struct ispstat *stat)
688 {
689 	/* Module will be re-enabled with its pipeline */
690 	if (stat->state == ISPSTAT_SUSPENDED)
691 		stat->state = ISPSTAT_ENABLING;
692 }
693 
694 static void isp_stat_try_enable(struct ispstat *stat)
695 {
696 	unsigned long irqflags;
697 
698 	if (stat->priv == NULL)
699 		/* driver wasn't initialised */
700 		return;
701 
702 	spin_lock_irqsave(&stat->isp->stat_lock, irqflags);
703 	if (stat->state == ISPSTAT_ENABLING && !stat->buf_processing &&
704 	    stat->buf_alloc_size) {
705 		/*
706 		 * Userspace's requested to enable the engine but it wasn't yet.
707 		 * Let's do that now.
708 		 */
709 		stat->update = 1;
710 		isp_stat_buf_next(stat);
711 		stat->ops->setup_regs(stat, stat->priv);
712 		isp_stat_buf_insert_magic(stat, stat->active_buf);
713 
714 		/*
715 		 * H3A module has some hw issues which forces the driver to
716 		 * ignore next buffers even if it was disabled in the meantime.
717 		 * On the other hand, Histogram shouldn't ignore buffers anymore
718 		 * if it's being enabled.
719 		 */
720 		if (!IS_H3A(stat))
721 			atomic_set(&stat->buf_err, 0);
722 
723 		isp_stat_pcr_enable(stat, 1);
724 		spin_unlock_irqrestore(&stat->isp->stat_lock, irqflags);
725 		dev_dbg(stat->isp->dev, "%s: module is enabled.\n",
726 			stat->subdev.name);
727 	} else {
728 		spin_unlock_irqrestore(&stat->isp->stat_lock, irqflags);
729 	}
730 }
731 
732 void omap3isp_stat_isr_frame_sync(struct ispstat *stat)
733 {
734 	isp_stat_try_enable(stat);
735 }
736 
737 void omap3isp_stat_sbl_overflow(struct ispstat *stat)
738 {
739 	unsigned long irqflags;
740 
741 	spin_lock_irqsave(&stat->isp->stat_lock, irqflags);
742 	/*
743 	 * Due to a H3A hw issue which prevents the next buffer to start from
744 	 * the correct memory address, 2 buffers must be ignored.
745 	 */
746 	atomic_set(&stat->buf_err, 2);
747 
748 	/*
749 	 * If more than one SBL overflow happen in a row, H3A module may access
750 	 * invalid memory region.
751 	 * stat->sbl_ovl_recover is set to tell to the driver to temporarily use
752 	 * a soft configuration which helps to avoid consecutive overflows.
753 	 */
754 	if (stat->recover_priv)
755 		stat->sbl_ovl_recover = 1;
756 	spin_unlock_irqrestore(&stat->isp->stat_lock, irqflags);
757 }
758 
759 /*
760  * omap3isp_stat_enable - Disable/Enable statistic engine as soon as possible
761  * @enable: 0/1 - Disables/Enables the engine.
762  *
763  * Client should configure all the module registers before this.
764  * This function can be called from a userspace request.
765  */
766 int omap3isp_stat_enable(struct ispstat *stat, u8 enable)
767 {
768 	unsigned long irqflags;
769 
770 	dev_dbg(stat->isp->dev, "%s: user wants to %s module.\n",
771 		stat->subdev.name, enable ? "enable" : "disable");
772 
773 	/* Prevent enabling while configuring */
774 	mutex_lock(&stat->ioctl_lock);
775 
776 	spin_lock_irqsave(&stat->isp->stat_lock, irqflags);
777 
778 	if (!stat->configured && enable) {
779 		spin_unlock_irqrestore(&stat->isp->stat_lock, irqflags);
780 		mutex_unlock(&stat->ioctl_lock);
781 		dev_dbg(stat->isp->dev,
782 			"%s: cannot enable module as it's never been successfully configured so far.\n",
783 			stat->subdev.name);
784 		return -EINVAL;
785 	}
786 
787 	if (enable) {
788 		if (stat->state == ISPSTAT_DISABLING)
789 			/* Previous disabling request wasn't done yet */
790 			stat->state = ISPSTAT_ENABLED;
791 		else if (stat->state == ISPSTAT_DISABLED)
792 			/* Module is now being enabled */
793 			stat->state = ISPSTAT_ENABLING;
794 	} else {
795 		if (stat->state == ISPSTAT_ENABLING) {
796 			/* Previous enabling request wasn't done yet */
797 			stat->state = ISPSTAT_DISABLED;
798 		} else if (stat->state == ISPSTAT_ENABLED) {
799 			/* Module is now being disabled */
800 			stat->state = ISPSTAT_DISABLING;
801 			isp_stat_buf_clear(stat);
802 		}
803 	}
804 
805 	spin_unlock_irqrestore(&stat->isp->stat_lock, irqflags);
806 	mutex_unlock(&stat->ioctl_lock);
807 
808 	return 0;
809 }
810 
811 int omap3isp_stat_s_stream(struct v4l2_subdev *subdev, int enable)
812 {
813 	struct ispstat *stat = v4l2_get_subdevdata(subdev);
814 
815 	if (enable) {
816 		/*
817 		 * Only set enable PCR bit if the module was previously
818 		 * enabled through ioctl.
819 		 */
820 		isp_stat_try_enable(stat);
821 	} else {
822 		unsigned long flags;
823 		/* Disable PCR bit and config enable field */
824 		omap3isp_stat_enable(stat, 0);
825 		spin_lock_irqsave(&stat->isp->stat_lock, flags);
826 		stat->ops->enable(stat, 0);
827 		spin_unlock_irqrestore(&stat->isp->stat_lock, flags);
828 
829 		/*
830 		 * If module isn't busy, a new interrupt may come or not to
831 		 * set the state to DISABLED. As Histogram needs to read its
832 		 * internal memory to clear it, let interrupt handler
833 		 * responsible of changing state to DISABLED. If the last
834 		 * interrupt is coming, it's still safe as the handler will
835 		 * ignore the second time when state is already set to DISABLED.
836 		 * It's necessary to synchronize Histogram with streamoff, once
837 		 * the module may be considered idle before last SDMA transfer
838 		 * starts if we return here.
839 		 */
840 		if (!omap3isp_stat_pcr_busy(stat))
841 			omap3isp_stat_isr(stat);
842 
843 		dev_dbg(stat->isp->dev, "%s: module is being disabled\n",
844 			stat->subdev.name);
845 	}
846 
847 	return 0;
848 }
849 
850 /*
851  * __stat_isr - Interrupt handler for statistic drivers
852  */
853 static void __stat_isr(struct ispstat *stat, int from_dma)
854 {
855 	int ret = STAT_BUF_DONE;
856 	int buf_processing;
857 	unsigned long irqflags;
858 	struct isp_pipeline *pipe;
859 
860 	/*
861 	 * stat->buf_processing must be set before disable module. It's
862 	 * necessary to not inform too early the buffers aren't busy in case
863 	 * of SDMA is going to be used.
864 	 */
865 	spin_lock_irqsave(&stat->isp->stat_lock, irqflags);
866 	if (stat->state == ISPSTAT_DISABLED) {
867 		spin_unlock_irqrestore(&stat->isp->stat_lock, irqflags);
868 		return;
869 	}
870 	buf_processing = stat->buf_processing;
871 	stat->buf_processing = 1;
872 	stat->ops->enable(stat, 0);
873 
874 	if (buf_processing && !from_dma) {
875 		if (stat->state == ISPSTAT_ENABLED) {
876 			spin_unlock_irqrestore(&stat->isp->stat_lock, irqflags);
877 			dev_err(stat->isp->dev,
878 				"%s: interrupt occurred when module was still processing a buffer.\n",
879 				stat->subdev.name);
880 			ret = STAT_NO_BUF;
881 			goto out;
882 		} else {
883 			/*
884 			 * Interrupt handler was called from streamoff when
885 			 * the module wasn't busy anymore to ensure it is being
886 			 * disabled after process last buffer. If such buffer
887 			 * processing has already started, no need to do
888 			 * anything else.
889 			 */
890 			spin_unlock_irqrestore(&stat->isp->stat_lock, irqflags);
891 			return;
892 		}
893 	}
894 	spin_unlock_irqrestore(&stat->isp->stat_lock, irqflags);
895 
896 	/* If it's busy we can't process this buffer anymore */
897 	if (!omap3isp_stat_pcr_busy(stat)) {
898 		if (!from_dma && stat->ops->buf_process)
899 			/* Module still need to copy data to buffer. */
900 			ret = stat->ops->buf_process(stat);
901 		if (ret == STAT_BUF_WAITING_DMA)
902 			/* Buffer is not ready yet */
903 			return;
904 
905 		spin_lock_irqsave(&stat->isp->stat_lock, irqflags);
906 
907 		/*
908 		 * Histogram needs to read its internal memory to clear it
909 		 * before be disabled. For that reason, common statistic layer
910 		 * can return only after call stat's buf_process() operator.
911 		 */
912 		if (stat->state == ISPSTAT_DISABLING) {
913 			stat->state = ISPSTAT_DISABLED;
914 			spin_unlock_irqrestore(&stat->isp->stat_lock, irqflags);
915 			stat->buf_processing = 0;
916 			return;
917 		}
918 		pipe = to_isp_pipeline(&stat->subdev.entity);
919 		stat->frame_number = atomic_read(&pipe->frame_number);
920 
921 		/*
922 		 * Before this point, 'ret' stores the buffer's status if it's
923 		 * ready to be processed. Afterwards, it holds the status if
924 		 * it was processed successfully.
925 		 */
926 		ret = isp_stat_buf_process(stat, ret);
927 
928 		if (likely(!stat->sbl_ovl_recover)) {
929 			stat->ops->setup_regs(stat, stat->priv);
930 		} else {
931 			/*
932 			 * Using recover config to increase the chance to have
933 			 * a good buffer processing and make the H3A module to
934 			 * go back to a valid state.
935 			 */
936 			stat->update = 1;
937 			stat->ops->setup_regs(stat, stat->recover_priv);
938 			stat->sbl_ovl_recover = 0;
939 
940 			/*
941 			 * Set 'update' in case of the module needs to use
942 			 * regular configuration after next buffer.
943 			 */
944 			stat->update = 1;
945 		}
946 
947 		isp_stat_buf_insert_magic(stat, stat->active_buf);
948 
949 		/*
950 		 * Hack: H3A modules may access invalid memory address or send
951 		 * corrupted data to userspace if more than 1 SBL overflow
952 		 * happens in a row without re-writing its buffer's start memory
953 		 * address in the meantime. Such situation is avoided if the
954 		 * module is not immediately re-enabled when the ISR misses the
955 		 * timing to process the buffer and to setup the registers.
956 		 * Because of that, pcr_enable(1) was moved to inside this 'if'
957 		 * block. But the next interruption will still happen as during
958 		 * pcr_enable(0) the module was busy.
959 		 */
960 		isp_stat_pcr_enable(stat, 1);
961 		spin_unlock_irqrestore(&stat->isp->stat_lock, irqflags);
962 	} else {
963 		/*
964 		 * If a SBL overflow occurs and the H3A driver misses the timing
965 		 * to process the buffer, stat->buf_err is set and won't be
966 		 * cleared now. So the next buffer will be correctly ignored.
967 		 * It's necessary due to a hw issue which makes the next H3A
968 		 * buffer to start from the memory address where the previous
969 		 * one stopped, instead of start where it was configured to.
970 		 * Do not "stat->buf_err = 0" here.
971 		 */
972 
973 		if (stat->ops->buf_process)
974 			/*
975 			 * Driver may need to erase current data prior to
976 			 * process a new buffer. If it misses the timing, the
977 			 * next buffer might be wrong. So should be ignored.
978 			 * It happens only for Histogram.
979 			 */
980 			atomic_set(&stat->buf_err, 1);
981 
982 		ret = STAT_NO_BUF;
983 		dev_dbg(stat->isp->dev,
984 			"%s: cannot process buffer, device is busy.\n",
985 			stat->subdev.name);
986 	}
987 
988 out:
989 	stat->buf_processing = 0;
990 	isp_stat_queue_event(stat, ret != STAT_BUF_DONE);
991 }
992 
993 void omap3isp_stat_isr(struct ispstat *stat)
994 {
995 	__stat_isr(stat, 0);
996 }
997 
998 void omap3isp_stat_dma_isr(struct ispstat *stat)
999 {
1000 	__stat_isr(stat, 1);
1001 }
1002 
1003 int omap3isp_stat_subscribe_event(struct v4l2_subdev *subdev,
1004 				  struct v4l2_fh *fh,
1005 				  struct v4l2_event_subscription *sub)
1006 {
1007 	struct ispstat *stat = v4l2_get_subdevdata(subdev);
1008 
1009 	if (sub->type != stat->event_type)
1010 		return -EINVAL;
1011 
1012 	return v4l2_event_subscribe(fh, sub, STAT_NEVENTS, NULL);
1013 }
1014 
1015 int omap3isp_stat_unsubscribe_event(struct v4l2_subdev *subdev,
1016 				    struct v4l2_fh *fh,
1017 				    struct v4l2_event_subscription *sub)
1018 {
1019 	return v4l2_event_unsubscribe(fh, sub);
1020 }
1021 
1022 void omap3isp_stat_unregister_entities(struct ispstat *stat)
1023 {
1024 	v4l2_device_unregister_subdev(&stat->subdev);
1025 }
1026 
1027 int omap3isp_stat_register_entities(struct ispstat *stat,
1028 				    struct v4l2_device *vdev)
1029 {
1030 	stat->subdev.dev = vdev->mdev->dev;
1031 
1032 	return v4l2_device_register_subdev(vdev, &stat->subdev);
1033 }
1034 
1035 static int isp_stat_init_entities(struct ispstat *stat, const char *name,
1036 				  const struct v4l2_subdev_ops *sd_ops)
1037 {
1038 	struct v4l2_subdev *subdev = &stat->subdev;
1039 	struct media_entity *me = &subdev->entity;
1040 
1041 	v4l2_subdev_init(subdev, sd_ops);
1042 	snprintf(subdev->name, V4L2_SUBDEV_NAME_SIZE, "OMAP3 ISP %s", name);
1043 	subdev->grp_id = BIT(16);	/* group ID for isp subdevs */
1044 	subdev->flags |= V4L2_SUBDEV_FL_HAS_EVENTS | V4L2_SUBDEV_FL_HAS_DEVNODE;
1045 	v4l2_set_subdevdata(subdev, stat);
1046 
1047 	stat->pad.flags = MEDIA_PAD_FL_SINK | MEDIA_PAD_FL_MUST_CONNECT;
1048 	me->ops = NULL;
1049 
1050 	return media_entity_pads_init(me, 1, &stat->pad);
1051 }
1052 
1053 int omap3isp_stat_init(struct ispstat *stat, const char *name,
1054 		       const struct v4l2_subdev_ops *sd_ops)
1055 {
1056 	int ret;
1057 
1058 	stat->buf = kcalloc(STAT_MAX_BUFS, sizeof(*stat->buf), GFP_KERNEL);
1059 	if (!stat->buf)
1060 		return -ENOMEM;
1061 
1062 	isp_stat_buf_clear(stat);
1063 	mutex_init(&stat->ioctl_lock);
1064 	atomic_set(&stat->buf_err, 0);
1065 
1066 	ret = isp_stat_init_entities(stat, name, sd_ops);
1067 	if (ret < 0) {
1068 		mutex_destroy(&stat->ioctl_lock);
1069 		kfree(stat->buf);
1070 	}
1071 
1072 	return ret;
1073 }
1074 
1075 void omap3isp_stat_cleanup(struct ispstat *stat)
1076 {
1077 	media_entity_cleanup(&stat->subdev.entity);
1078 	mutex_destroy(&stat->ioctl_lock);
1079 	isp_stat_bufs_free(stat);
1080 	kfree(stat->buf);
1081 	kfree(stat->priv);
1082 	kfree(stat->recover_priv);
1083 }
1084