summaryrefslogtreecommitdiff
path: root/drivers/gpu/drm/drm_debugfs_crc.c
blob: e22b812c4b802c0e6610498b36aa30bf99efb54b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
/*
 * Copyright © 2008 Intel Corporation
 * Copyright © 2016 Collabora Ltd
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 * Based on code from the i915 driver.
 * Original author: Damien Lespiau <damien.lespiau@intel.com>
 *
 */

#include <linux/circ_buf.h>
#include <linux/ctype.h>
#include <linux/debugfs.h>
#include <linux/poll.h>
#include <linux/uaccess.h>

#include <drm/drm_crtc.h>
#include <drm/drm_debugfs_crc.h>
#include <drm/drm_drv.h>
#include <drm/drm_print.h>

#include "drm_internal.h"

/**
 * DOC: CRC ABI
 *
 * DRM device drivers can provide to userspace CRC information of each frame as
 * it reached a given hardware component (a CRC sampling "source").
 *
 * Userspace can control generation of CRCs in a given CRTC by writing to the
 * file dri/0/crtc-N/crc/control in debugfs, with N being the index of the CRTC.
 * Accepted values are source names (which are driver-specific) and the "auto"
 * keyword, which will let the driver select a default source of frame CRCs
 * for this CRTC.
 *
 * Once frame CRC generation is enabled, userspace can capture them by reading
 * the dri/0/crtc-N/crc/data file. Each line in that file contains the frame
 * number in the first field and then a number of unsigned integer fields
 * containing the CRC data. Fields are separated by a single space and the number
 * of CRC fields is source-specific.
 *
 * Note that though in some cases the CRC is computed in a specified way and on
 * the frame contents as supplied by userspace (eDP 1.3), in general the CRC
 * computation is performed in an unspecified way and on frame contents that have
 * been already processed in also an unspecified way and thus userspace cannot
 * rely on being able to generate matching CRC values for the frame contents that
 * it submits. In this general case, the maximum userspace can do is to compare
 * the reported CRCs of frames that should have the same contents.
 *
 * On the driver side the implementation effort is minimal, drivers only need to
 * implement &drm_crtc_funcs.set_crc_source and &drm_crtc_funcs.verify_crc_source.
 * The debugfs files are automatically set up if those vfuncs are set. CRC samples
 * need to be captured in the driver by calling drm_crtc_add_crc_entry().
 * Depending on the driver and HW requirements, &drm_crtc_funcs.set_crc_source
 * may result in a commit (even a full modeset).
 *
 * CRC results must be reliable across non-full-modeset atomic commits, so if a
 * commit via DRM_IOCTL_MODE_ATOMIC would disable or otherwise interfere with
 * CRC generation, then the driver must mark that commit as a full modeset
 * (drm_atomic_crtc_needs_modeset() should return true). As a result, to ensure
 * consistent results, generic userspace must re-setup CRC generation after a
 * legacy SETCRTC or an atomic commit with DRM_MODE_ATOMIC_ALLOW_MODESET.
 */

static int crc_control_show(struct seq_file *m, void *data)
{
	struct drm_crtc *crtc = m->private;

	if (crtc->funcs->get_crc_sources) {
		size_t count;
		const char *const *sources = crtc->funcs->get_crc_sources(crtc,
									&count);
		size_t values_cnt;
		int i;

		if (count == 0 || !sources)
			goto out;

		for (i = 0; i < count; i++)
			if (!crtc->funcs->verify_crc_source(crtc, sources[i],
							    &values_cnt)) {
				if (strcmp(sources[i], crtc->crc.source))
					seq_printf(m, "%s\n", sources[i]);
				else
					seq_printf(m, "%s*\n", sources[i]);
			}
	}
	return 0;

out:
	seq_printf(m, "%s*\n", crtc->crc.source);
	return 0;
}

static int crc_control_open(struct inode *inode, struct file *file)
{
	struct drm_crtc *crtc = inode->i_private;

	return single_open(file, crc_control_show, crtc);
}

static ssize_t crc_control_write(struct file *file, const char __user *ubuf,
				 size_t len, loff_t *offp)
{
	struct seq_file *m = file->private_data;
	struct drm_crtc *crtc = m->private;
	struct drm_crtc_crc *crc = &crtc->crc;
	char *source;
	size_t values_cnt;
	int ret;

	if (len == 0)
		return 0;

	if (len > PAGE_SIZE - 1) {
		DRM_DEBUG_KMS("Expected < %lu bytes into crtc crc control\n",
			      PAGE_SIZE);
		return -E2BIG;
	}

	source = memdup_user_nul(ubuf, len);
	if (IS_ERR(source))
		return PTR_ERR(source);

	if (source[len - 1] == '\n')
		source[len - 1] = '\0';

	ret = crtc->funcs->verify_crc_source(crtc, source, &values_cnt);
	if (ret)
		return ret;

	spin_lock_irq(&crc->lock);

	if (crc->opened) {
		spin_unlock_irq(&crc->lock);
		kfree(source);
		return -EBUSY;
	}

	kfree(crc->source);
	crc->source = source;

	spin_unlock_irq(&crc->lock);

	*offp += len;
	return len;
}

static const struct file_operations drm_crtc_crc_control_fops = {
	.owner = THIS_MODULE,
	.open = crc_control_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = single_release,
	.write = crc_control_write
};

static int crtc_crc_data_count(struct drm_crtc_crc *crc)
{
	assert_spin_locked(&crc->lock);
	return CIRC_CNT(crc->head, crc->tail, DRM_CRC_ENTRIES_NR);
}

static void crtc_crc_cleanup(struct drm_crtc_crc *crc)
{
	kfree(crc->entries);
	crc->overflow = false;
	crc->entries = NULL;
	crc->head = 0;
	crc->tail = 0;
	crc->values_cnt = 0;
	crc->opened = false;
}

static int crtc_crc_open(struct inode *inode, struct file *filep)
{
	struct drm_crtc *crtc = inode->i_private;
	struct drm_crtc_crc *crc = &crtc->crc;
	struct drm_crtc_crc_entry *entries = NULL;
	size_t values_cnt;
	int ret = 0;

	if (drm_drv_uses_atomic_modeset(crtc->dev)) {
		ret = drm_modeset_lock_single_interruptible(&crtc->mutex);
		if (ret)
			return ret;

		if (!crtc->state->active)
			ret = -EIO;
		drm_modeset_unlock(&crtc->mutex);

		if (ret)
			return ret;
	}

	ret = crtc->funcs->verify_crc_source(crtc, crc->source, &values_cnt);
	if (ret)
		return ret;

	if (WARN_ON(values_cnt > DRM_MAX_CRC_NR))
		return -EINVAL;

	if (WARN_ON(values_cnt == 0))
		return -EINVAL;

	entries = kcalloc(DRM_CRC_ENTRIES_NR, sizeof(*entries), GFP_KERNEL);
	if (!entries)
		return -ENOMEM;

	spin_lock_irq(&crc->lock);
	if (!crc->opened) {
		crc->opened = true;
		crc->entries = entries;
		crc->values_cnt = values_cnt;
	} else {
		ret = -EBUSY;
	}
	spin_unlock_irq(&crc->lock);

	if (ret) {
		kfree(entries);
		return ret;
	}

	ret = crtc->funcs->set_crc_source(crtc, crc->source);
	if (ret)
		goto err;

	return 0;

err:
	spin_lock_irq(&crc->lock);
	crtc_crc_cleanup(crc);
	spin_unlock_irq(&crc->lock);
	return ret;
}

static int crtc_crc_release(struct inode *inode, struct file *filep)
{
	struct drm_crtc *crtc = filep->f_inode->i_private;
	struct drm_crtc_crc *crc = &crtc->crc;

	/* terminate the infinite while loop if 'drm_dp_aux_crc_work' running */
	spin_lock_irq(&crc->lock);
	crc->opened = false;
	spin_unlock_irq(&crc->lock);

	crtc->funcs->set_crc_source(crtc, NULL);

	spin_lock_irq(&crc->lock);
	crtc_crc_cleanup(crc);
	spin_unlock_irq(&crc->lock);

	return 0;
}

/*
 * 1 frame field of 10 chars plus a number of CRC fields of 10 chars each, space
 * separated, with a newline at the end and null-terminated.
 */
#define LINE_LEN(values_cnt)	(10 + 11 * values_cnt + 1 + 1)
#define MAX_LINE_LEN		(LINE_LEN(DRM_MAX_CRC_NR))

static ssize_t crtc_crc_read(struct file *filep, char __user *user_buf,
			     size_t count, loff_t *pos)
{
	struct drm_crtc *crtc = filep->f_inode->i_private;
	struct drm_crtc_crc *crc = &crtc->crc;
	struct drm_crtc_crc_entry *entry;
	char buf[MAX_LINE_LEN];
	int ret, i;

	spin_lock_irq(&crc->lock);

	if (!crc->source) {
		spin_unlock_irq(&crc->lock);
		return 0;
	}

	/* Nothing to read? */
	while (crtc_crc_data_count(crc) == 0) {
		if (filep->f_flags & O_NONBLOCK) {
			spin_unlock_irq(&crc->lock);
			return -EAGAIN;
		}

		ret = wait_event_interruptible_lock_irq(crc->wq,
							crtc_crc_data_count(crc),
							crc->lock);
		if (ret) {
			spin_unlock_irq(&crc->lock);
			return ret;
		}
	}

	/* We know we have an entry to be read */
	entry = &crc->entries[crc->tail];

	if (count < LINE_LEN(crc->values_cnt)) {
		spin_unlock_irq(&crc->lock);
		return -EINVAL;
	}

	BUILD_BUG_ON_NOT_POWER_OF_2(DRM_CRC_ENTRIES_NR);
	crc->tail = (crc->tail + 1) & (DRM_CRC_ENTRIES_NR - 1);

	spin_unlock_irq(&crc->lock);

	if (entry->has_frame_counter)
		sprintf(buf, "0x%08x", entry->frame);
	else
		sprintf(buf, "XXXXXXXXXX");

	for (i = 0; i < crc->values_cnt; i++)
		sprintf(buf + 10 + i * 11, " 0x%08x", entry->crcs[i]);
	sprintf(buf + 10 + crc->values_cnt * 11, "\n");

	if (copy_to_user(user_buf, buf, LINE_LEN(crc->values_cnt)))
		return -EFAULT;

	return LINE_LEN(crc->values_cnt);
}

static __poll_t crtc_crc_poll(struct file *file, poll_table *wait)
{
	struct drm_crtc *crtc = file->f_inode->i_private;
	struct drm_crtc_crc *crc = &crtc->crc;
	__poll_t ret = 0;

	poll_wait(file, &crc->wq, wait);

	spin_lock_irq(&crc->lock);
	if (crc->source && crtc_crc_data_count(crc))
		ret |= EPOLLIN | EPOLLRDNORM;
	spin_unlock_irq(&crc->lock);

	return ret;
}

static const struct file_operations drm_crtc_crc_data_fops = {
	.owner = THIS_MODULE,
	.open = crtc_crc_open,
	.read = crtc_crc_read,
	.poll = crtc_crc_poll,
	.release = crtc_crc_release,
};

void drm_debugfs_crtc_crc_add(struct drm_crtc *crtc)
{
	struct dentry *crc_ent;

	if (!crtc->funcs->set_crc_source || !crtc->funcs->verify_crc_source)
		return;

	crc_ent = debugfs_create_dir("crc", crtc->debugfs_entry);

	debugfs_create_file("control", S_IRUGO, crc_ent, crtc,
			    &drm_crtc_crc_control_fops);
	debugfs_create_file("data", S_IRUGO, crc_ent, crtc,
			    &drm_crtc_crc_data_fops);
}

/**
 * drm_crtc_add_crc_entry - Add entry with CRC information for a frame
 * @crtc: CRTC to which the frame belongs
 * @has_frame: whether this entry has a frame number to go with
 * @frame: number of the frame these CRCs are about
 * @crcs: array of CRC values, with length matching #drm_crtc_crc.values_cnt
 *
 * For each frame, the driver polls the source of CRCs for new data and calls
 * this function to add them to the buffer from where userspace reads.
 */
int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame,
			   uint32_t frame, uint32_t *crcs)
{
	struct drm_crtc_crc *crc = &crtc->crc;
	struct drm_crtc_crc_entry *entry;
	int head, tail;
	unsigned long flags;

	spin_lock_irqsave(&crc->lock, flags);

	/* Caller may not have noticed yet that userspace has stopped reading */
	if (!crc->entries) {
		spin_unlock_irqrestore(&crc->lock, flags);
		return -EINVAL;
	}

	head = crc->head;
	tail = crc->tail;

	if (CIRC_SPACE(head, tail, DRM_CRC_ENTRIES_NR) < 1) {
		bool was_overflow = crc->overflow;

		crc->overflow = true;
		spin_unlock_irqrestore(&crc->lock, flags);

		if (!was_overflow)
			DRM_ERROR("Overflow of CRC buffer, userspace reads too slow.\n");

		return -ENOBUFS;
	}

	entry = &crc->entries[head];
	entry->frame = frame;
	entry->has_frame_counter = has_frame;
	memcpy(&entry->crcs, crcs, sizeof(*crcs) * crc->values_cnt);

	head = (head + 1) & (DRM_CRC_ENTRIES_NR - 1);
	crc->head = head;

	spin_unlock_irqrestore(&crc->lock, flags);

	wake_up_interruptible(&crc->wq);

	return 0;
}
EXPORT_SYMBOL_GPL(drm_crtc_add_crc_entry);