36  * DOC: CRC ABI
38  * DRM device drivers can provide to userspace CRC information of each frame as
39  * it reached a given hardware component (a CRC sampling "source").
42  * file dri/0/crtc-N/crc/control in debugfs, with N being the index of the CRTC.
47  * Once frame CRC generation is enabled, userspace can capture them by reading
48  * the dri/0/crtc-N/crc/data file. Each line in that file contains the frame
50  * containing the CRC data. Fields are separated by a single space and the number
51  * of CRC fields is source-specific.
53  * Note that though in some cases the CRC is computed in a specified way and on
54  * the frame contents as supplied by userspace (eDP 1.3), in general the CRC
57  * rely on being able to generate matching CRC values for the frame contents that
63  * set up if that vfunc is set. CRC samples need to be captured in the driver by
71 	seq_printf(m, "%s\n", crtc->crc.source);  in crc_control_show()
88 	struct drm_crtc_crc *crc = &crtc->crc;  in crc_control_write()  local
95 		DRM_DEBUG_KMS("Expected < %lu bytes into crtc crc control\n",  in crc_control_write()
107 	spin_lock_irq(&crc->lock);  in crc_control_write()
109 	if (crc->opened) {  in crc_control_write()
110 		spin_unlock_irq(&crc->lock);  in crc_control_write()
115 	kfree(crc->source);  in crc_control_write()
116 	crc->source = source;  in crc_control_write()
118 	spin_unlock_irq(&crc->lock);  in crc_control_write()
133 static int crtc_crc_data_count(struct drm_crtc_crc *crc)  in crtc_crc_data_count()  argument
135 	assert_spin_locked(&crc->lock);  in crtc_crc_data_count()
136 	return CIRC_CNT(crc->head, crc->tail, DRM_CRC_ENTRIES_NR);  in crtc_crc_data_count()
139 static void crtc_crc_cleanup(struct drm_crtc_crc *crc)  in crtc_crc_cleanup()  argument
141 	kfree(crc->entries);  in crtc_crc_cleanup()
142 	crc->overflow = false;  in crtc_crc_cleanup()
143 	crc->entries = NULL;  in crtc_crc_cleanup()
144 	crc->head = 0;  in crtc_crc_cleanup()
145 	crc->tail = 0;  in crtc_crc_cleanup()
146 	crc->values_cnt = 0;  in crtc_crc_cleanup()
147 	crc->opened = false;  in crtc_crc_cleanup()
153 	struct drm_crtc_crc *crc = &crtc->crc;  in crtc_crc_open()  local
171 	spin_lock_irq(&crc->lock);  in crtc_crc_open()
172 	if (!crc->opened)  in crtc_crc_open()
173 		crc->opened = true;  in crtc_crc_open()
176 	spin_unlock_irq(&crc->lock);  in crtc_crc_open()
181 	ret = crtc->funcs->set_crc_source(crtc, crc->source, &values_cnt);  in crtc_crc_open()
201 	spin_lock_irq(&crc->lock);  in crtc_crc_open()
202 	crc->entries = entries;  in crtc_crc_open()
203 	crc->values_cnt = values_cnt;  in crtc_crc_open()
210 	ret = wait_event_interruptible_lock_irq(crc->wq,  in crtc_crc_open()
211 						crtc_crc_data_count(crc),  in crtc_crc_open()
212 						crc->lock);  in crtc_crc_open()
213 	spin_unlock_irq(&crc->lock);  in crtc_crc_open()
223 	spin_lock_irq(&crc->lock);  in crtc_crc_open()
224 	crtc_crc_cleanup(crc);  in crtc_crc_open()
225 	spin_unlock_irq(&crc->lock);  in crtc_crc_open()
232 	struct drm_crtc_crc *crc = &crtc->crc;  in crtc_crc_release()  local
237 	spin_lock_irq(&crc->lock);  in crtc_crc_release()
238 	crtc_crc_cleanup(crc);  in crtc_crc_release()
239 	spin_unlock_irq(&crc->lock);  in crtc_crc_release()
245  * 1 frame field of 10 chars plus a number of CRC fields of 10 chars each, space
255 	struct drm_crtc_crc *crc = &crtc->crc;  in crtc_crc_read()  local
260 	spin_lock_irq(&crc->lock);  in crtc_crc_read()
262 	if (!crc->source) {  in crtc_crc_read()
263 		spin_unlock_irq(&crc->lock);  in crtc_crc_read()
268 	while (crtc_crc_data_count(crc) == 0) {  in crtc_crc_read()
270 			spin_unlock_irq(&crc->lock);  in crtc_crc_read()
274 		ret = wait_event_interruptible_lock_irq(crc->wq,  in crtc_crc_read()
275 							crtc_crc_data_count(crc),  in crtc_crc_read()
276 							crc->lock);  in crtc_crc_read()
278 			spin_unlock_irq(&crc->lock);  in crtc_crc_read()
284 	entry = &crc->entries[crc->tail];  in crtc_crc_read()
286 	if (count < LINE_LEN(crc->values_cnt)) {  in crtc_crc_read()
287 		spin_unlock_irq(&crc->lock);  in crtc_crc_read()
292 	crc->tail = (crc->tail + 1) & (DRM_CRC_ENTRIES_NR - 1);  in crtc_crc_read()
294 	spin_unlock_irq(&crc->lock);  in crtc_crc_read()
301 	for (i = 0; i < crc->values_cnt; i++)  in crtc_crc_read()
303 	sprintf(buf + 10 + crc->values_cnt * 11, "\n");  in crtc_crc_read()
305 	if (copy_to_user(user_buf, buf, LINE_LEN(crc->values_cnt)))  in crtc_crc_read()
308 	return LINE_LEN(crc->values_cnt);  in crtc_crc_read()
314 	struct drm_crtc_crc *crc = &crtc->crc;  in crtc_crc_poll()  local
317 	poll_wait(file, &crc->wq, wait);  in crtc_crc_poll()
319 	spin_lock_irq(&crc->lock);  in crtc_crc_poll()
320 	if (crc->source && crtc_crc_data_count(crc))  in crtc_crc_poll()
324 	spin_unlock_irq(&crc->lock);  in crtc_crc_poll()
344 	crc_ent = debugfs_create_dir("crc", crtc->debugfs_entry);  in drm_debugfs_crtc_crc_add()
367  * drm_crtc_add_crc_entry - Add entry with CRC information for a frame
371  * @crcs: array of CRC values, with length matching #drm_crtc_crc.values_cnt
379 	struct drm_crtc_crc *crc = &crtc->crc;  in drm_crtc_add_crc_entry()  local
384 	spin_lock_irqsave(&crc->lock, flags);  in drm_crtc_add_crc_entry()
387 	if (!crc->entries) {  in drm_crtc_add_crc_entry()
388 		spin_unlock_irqrestore(&crc->lock, flags);  in drm_crtc_add_crc_entry()
392 	head = crc->head;  in drm_crtc_add_crc_entry()
393 	tail = crc->tail;  in drm_crtc_add_crc_entry()
396 		bool was_overflow = crc->overflow;  in drm_crtc_add_crc_entry()
398 		crc->overflow = true;  in drm_crtc_add_crc_entry()
399 		spin_unlock_irqrestore(&crc->lock, flags);  in drm_crtc_add_crc_entry()
402 			DRM_ERROR("Overflow of CRC buffer, userspace reads too slow.\n");  in drm_crtc_add_crc_entry()
407 	entry = &crc->entries[head];  in drm_crtc_add_crc_entry()
410 	memcpy(&entry->crcs, crcs, sizeof(*crcs) * crc->values_cnt);  in drm_crtc_add_crc_entry()
413 	crc->head = head;  in drm_crtc_add_crc_entry()
415 	spin_unlock_irqrestore(&crc->lock, flags);  in drm_crtc_add_crc_entry()
417 	wake_up_interruptible(&crc->wq);  in drm_crtc_add_crc_entry()