1 // SPDX-License-Identifier: MIT
2 /*
3  * Copyright © 2014-2019 Intel Corporation
4  */
5 
6 #include <linux/debugfs.h>
7 #include <linux/string_helpers.h>
8 
9 #include "gt/intel_gt.h"
10 #include "i915_drv.h"
11 #include "i915_irq.h"
12 #include "i915_memcpy.h"
13 #include "intel_guc_capture.h"
14 #include "intel_guc_log.h"
15 
16 static void guc_log_copy_debuglogs_for_relay(struct intel_guc_log *log);
17 
18 static u32 intel_guc_log_size(struct intel_guc_log *log)
19 {
20 	/*
21 	 *  GuC Log buffer Layout:
22 	 *
23 	 *  NB: Ordering must follow "enum guc_log_buffer_type".
24 	 *
25 	 *  +===============================+ 00B
26 	 *  |      Debug state header       |
27 	 *  +-------------------------------+ 32B
28 	 *  |    Crash dump state header    |
29 	 *  +-------------------------------+ 64B
30 	 *  |     Capture state header      |
31 	 *  +-------------------------------+ 96B
32 	 *  |                               |
33 	 *  +===============================+ PAGE_SIZE (4KB)
34 	 *  |          Debug logs           |
35 	 *  +===============================+ + DEBUG_SIZE
36 	 *  |        Crash Dump logs        |
37 	 *  +===============================+ + CRASH_SIZE
38 	 *  |         Capture logs          |
39 	 *  +===============================+ + CAPTURE_SIZE
40 	 */
41 	return PAGE_SIZE + CRASH_BUFFER_SIZE + DEBUG_BUFFER_SIZE + CAPTURE_BUFFER_SIZE;
42 }
43 
44 /**
45  * DOC: GuC firmware log
46  *
47  * Firmware log is enabled by setting i915.guc_log_level to the positive level.
48  * Log data is printed out via reading debugfs i915_guc_log_dump. Reading from
49  * i915_guc_load_status will print out firmware loading status and scratch
50  * registers value.
51  */
52 
53 static int guc_action_flush_log_complete(struct intel_guc *guc)
54 {
55 	u32 action[] = {
56 		INTEL_GUC_ACTION_LOG_BUFFER_FILE_FLUSH_COMPLETE,
57 		GUC_DEBUG_LOG_BUFFER
58 	};
59 
60 	return intel_guc_send_nb(guc, action, ARRAY_SIZE(action), 0);
61 }
62 
63 static int guc_action_flush_log(struct intel_guc *guc)
64 {
65 	u32 action[] = {
66 		INTEL_GUC_ACTION_FORCE_LOG_BUFFER_FLUSH,
67 		0
68 	};
69 
70 	return intel_guc_send(guc, action, ARRAY_SIZE(action));
71 }
72 
73 static int guc_action_control_log(struct intel_guc *guc, bool enable,
74 				  bool default_logging, u32 verbosity)
75 {
76 	u32 action[] = {
77 		INTEL_GUC_ACTION_UK_LOG_ENABLE_LOGGING,
78 		(enable ? GUC_LOG_CONTROL_LOGGING_ENABLED : 0) |
79 		(verbosity << GUC_LOG_CONTROL_VERBOSITY_SHIFT) |
80 		(default_logging ? GUC_LOG_CONTROL_DEFAULT_LOGGING : 0)
81 	};
82 
83 	GEM_BUG_ON(verbosity > GUC_LOG_VERBOSITY_MAX);
84 
85 	return intel_guc_send(guc, action, ARRAY_SIZE(action));
86 }
87 
88 /*
89  * Sub buffer switch callback. Called whenever relay has to switch to a new
90  * sub buffer, relay stays on the same sub buffer if 0 is returned.
91  */
92 static int subbuf_start_callback(struct rchan_buf *buf,
93 				 void *subbuf,
94 				 void *prev_subbuf,
95 				 size_t prev_padding)
96 {
97 	/*
98 	 * Use no-overwrite mode by default, where relay will stop accepting
99 	 * new data if there are no empty sub buffers left.
100 	 * There is no strict synchronization enforced by relay between Consumer
101 	 * and Producer. In overwrite mode, there is a possibility of getting
102 	 * inconsistent/garbled data, the producer could be writing on to the
103 	 * same sub buffer from which Consumer is reading. This can't be avoided
104 	 * unless Consumer is fast enough and can always run in tandem with
105 	 * Producer.
106 	 */
107 	if (relay_buf_full(buf))
108 		return 0;
109 
110 	return 1;
111 }
112 
113 /*
114  * file_create() callback. Creates relay file in debugfs.
115  */
116 static struct dentry *create_buf_file_callback(const char *filename,
117 					       struct dentry *parent,
118 					       umode_t mode,
119 					       struct rchan_buf *buf,
120 					       int *is_global)
121 {
122 	struct dentry *buf_file;
123 
124 	/*
125 	 * This to enable the use of a single buffer for the relay channel and
126 	 * correspondingly have a single file exposed to User, through which
127 	 * it can collect the logs in order without any post-processing.
128 	 * Need to set 'is_global' even if parent is NULL for early logging.
129 	 */
130 	*is_global = 1;
131 
132 	if (!parent)
133 		return NULL;
134 
135 	buf_file = debugfs_create_file(filename, mode,
136 				       parent, buf, &relay_file_operations);
137 	if (IS_ERR(buf_file))
138 		return NULL;
139 
140 	return buf_file;
141 }
142 
143 /*
144  * file_remove() default callback. Removes relay file in debugfs.
145  */
146 static int remove_buf_file_callback(struct dentry *dentry)
147 {
148 	debugfs_remove(dentry);
149 	return 0;
150 }
151 
152 /* relay channel callbacks */
153 static const struct rchan_callbacks relay_callbacks = {
154 	.subbuf_start = subbuf_start_callback,
155 	.create_buf_file = create_buf_file_callback,
156 	.remove_buf_file = remove_buf_file_callback,
157 };
158 
159 static void guc_move_to_next_buf(struct intel_guc_log *log)
160 {
161 	/*
162 	 * Make sure the updates made in the sub buffer are visible when
163 	 * Consumer sees the following update to offset inside the sub buffer.
164 	 */
165 	smp_wmb();
166 
167 	/* All data has been written, so now move the offset of sub buffer. */
168 	relay_reserve(log->relay.channel, log->vma->obj->base.size - CAPTURE_BUFFER_SIZE);
169 
170 	/* Switch to the next sub buffer */
171 	relay_flush(log->relay.channel);
172 }
173 
174 static void *guc_get_write_buffer(struct intel_guc_log *log)
175 {
176 	/*
177 	 * Just get the base address of a new sub buffer and copy data into it
178 	 * ourselves. NULL will be returned in no-overwrite mode, if all sub
179 	 * buffers are full. Could have used the relay_write() to indirectly
180 	 * copy the data, but that would have been bit convoluted, as we need to
181 	 * write to only certain locations inside a sub buffer which cannot be
182 	 * done without using relay_reserve() along with relay_write(). So its
183 	 * better to use relay_reserve() alone.
184 	 */
185 	return relay_reserve(log->relay.channel, 0);
186 }
187 
188 bool intel_guc_check_log_buf_overflow(struct intel_guc_log *log,
189 				      enum guc_log_buffer_type type,
190 				      unsigned int full_cnt)
191 {
192 	unsigned int prev_full_cnt = log->stats[type].sampled_overflow;
193 	bool overflow = false;
194 
195 	if (full_cnt != prev_full_cnt) {
196 		overflow = true;
197 
198 		log->stats[type].overflow = full_cnt;
199 		log->stats[type].sampled_overflow += full_cnt - prev_full_cnt;
200 
201 		if (full_cnt < prev_full_cnt) {
202 			/* buffer_full_cnt is a 4 bit counter */
203 			log->stats[type].sampled_overflow += 16;
204 		}
205 
206 		dev_notice_ratelimited(guc_to_gt(log_to_guc(log))->i915->drm.dev,
207 				       "GuC log buffer overflow\n");
208 	}
209 
210 	return overflow;
211 }
212 
213 unsigned int intel_guc_get_log_buffer_size(enum guc_log_buffer_type type)
214 {
215 	switch (type) {
216 	case GUC_DEBUG_LOG_BUFFER:
217 		return DEBUG_BUFFER_SIZE;
218 	case GUC_CRASH_DUMP_LOG_BUFFER:
219 		return CRASH_BUFFER_SIZE;
220 	case GUC_CAPTURE_LOG_BUFFER:
221 		return CAPTURE_BUFFER_SIZE;
222 	default:
223 		MISSING_CASE(type);
224 	}
225 
226 	return 0;
227 }
228 
229 size_t intel_guc_get_log_buffer_offset(enum guc_log_buffer_type type)
230 {
231 	enum guc_log_buffer_type i;
232 	size_t offset = PAGE_SIZE;/* for the log_buffer_states */
233 
234 	for (i = GUC_DEBUG_LOG_BUFFER; i < GUC_MAX_LOG_BUFFER; ++i) {
235 		if (i == type)
236 			break;
237 		offset += intel_guc_get_log_buffer_size(i);
238 	}
239 
240 	return offset;
241 }
242 
243 static void _guc_log_copy_debuglogs_for_relay(struct intel_guc_log *log)
244 {
245 	unsigned int buffer_size, read_offset, write_offset, bytes_to_copy, full_cnt;
246 	struct guc_log_buffer_state *log_buf_state, *log_buf_snapshot_state;
247 	struct guc_log_buffer_state log_buf_state_local;
248 	enum guc_log_buffer_type type;
249 	void *src_data, *dst_data;
250 	bool new_overflow;
251 
252 	mutex_lock(&log->relay.lock);
253 
254 	if (WARN_ON(!intel_guc_log_relay_created(log)))
255 		goto out_unlock;
256 
257 	/* Get the pointer to shared GuC log buffer */
258 	src_data = log->buf_addr;
259 	log_buf_state = src_data;
260 
261 	/* Get the pointer to local buffer to store the logs */
262 	log_buf_snapshot_state = dst_data = guc_get_write_buffer(log);
263 
264 	if (unlikely(!log_buf_snapshot_state)) {
265 		/*
266 		 * Used rate limited to avoid deluge of messages, logs might be
267 		 * getting consumed by User at a slow rate.
268 		 */
269 		DRM_ERROR_RATELIMITED("no sub-buffer to copy general logs\n");
270 		log->relay.full_count++;
271 
272 		goto out_unlock;
273 	}
274 
275 	/* Actual logs are present from the 2nd page */
276 	src_data += PAGE_SIZE;
277 	dst_data += PAGE_SIZE;
278 
279 	/* For relay logging, we exclude error state capture */
280 	for (type = GUC_DEBUG_LOG_BUFFER; type <= GUC_CRASH_DUMP_LOG_BUFFER; type++) {
281 		/*
282 		 * Make a copy of the state structure, inside GuC log buffer
283 		 * (which is uncached mapped), on the stack to avoid reading
284 		 * from it multiple times.
285 		 */
286 		memcpy(&log_buf_state_local, log_buf_state,
287 		       sizeof(struct guc_log_buffer_state));
288 		buffer_size = intel_guc_get_log_buffer_size(type);
289 		read_offset = log_buf_state_local.read_ptr;
290 		write_offset = log_buf_state_local.sampled_write_ptr;
291 		full_cnt = log_buf_state_local.buffer_full_cnt;
292 
293 		/* Bookkeeping stuff */
294 		log->stats[type].flush += log_buf_state_local.flush_to_file;
295 		new_overflow = intel_guc_check_log_buf_overflow(log, type, full_cnt);
296 
297 		/* Update the state of shared log buffer */
298 		log_buf_state->read_ptr = write_offset;
299 		log_buf_state->flush_to_file = 0;
300 		log_buf_state++;
301 
302 		/* First copy the state structure in snapshot buffer */
303 		memcpy(log_buf_snapshot_state, &log_buf_state_local,
304 		       sizeof(struct guc_log_buffer_state));
305 
306 		/*
307 		 * The write pointer could have been updated by GuC firmware,
308 		 * after sending the flush interrupt to Host, for consistency
309 		 * set write pointer value to same value of sampled_write_ptr
310 		 * in the snapshot buffer.
311 		 */
312 		log_buf_snapshot_state->write_ptr = write_offset;
313 		log_buf_snapshot_state++;
314 
315 		/* Now copy the actual logs. */
316 		if (unlikely(new_overflow)) {
317 			/* copy the whole buffer in case of overflow */
318 			read_offset = 0;
319 			write_offset = buffer_size;
320 		} else if (unlikely((read_offset > buffer_size) ||
321 				    (write_offset > buffer_size))) {
322 			DRM_ERROR("invalid log buffer state\n");
323 			/* copy whole buffer as offsets are unreliable */
324 			read_offset = 0;
325 			write_offset = buffer_size;
326 		}
327 
328 		/* Just copy the newly written data */
329 		if (read_offset > write_offset) {
330 			i915_memcpy_from_wc(dst_data, src_data, write_offset);
331 			bytes_to_copy = buffer_size - read_offset;
332 		} else {
333 			bytes_to_copy = write_offset - read_offset;
334 		}
335 		i915_memcpy_from_wc(dst_data + read_offset,
336 				    src_data + read_offset, bytes_to_copy);
337 
338 		src_data += buffer_size;
339 		dst_data += buffer_size;
340 	}
341 
342 	guc_move_to_next_buf(log);
343 
344 out_unlock:
345 	mutex_unlock(&log->relay.lock);
346 }
347 
348 static void copy_debug_logs_work(struct work_struct *work)
349 {
350 	struct intel_guc_log *log =
351 		container_of(work, struct intel_guc_log, relay.flush_work);
352 
353 	guc_log_copy_debuglogs_for_relay(log);
354 }
355 
356 static int guc_log_relay_map(struct intel_guc_log *log)
357 {
358 	lockdep_assert_held(&log->relay.lock);
359 
360 	if (!log->vma || !log->buf_addr)
361 		return -ENODEV;
362 
363 	/*
364 	 * WC vmalloc mapping of log buffer pages was done at
365 	 * GuC Log Init time, but lets keep a ref for book-keeping
366 	 */
367 	i915_gem_object_get(log->vma->obj);
368 	log->relay.buf_in_use = true;
369 
370 	return 0;
371 }
372 
373 static void guc_log_relay_unmap(struct intel_guc_log *log)
374 {
375 	lockdep_assert_held(&log->relay.lock);
376 
377 	i915_gem_object_put(log->vma->obj);
378 	log->relay.buf_in_use = false;
379 }
380 
381 void intel_guc_log_init_early(struct intel_guc_log *log)
382 {
383 	mutex_init(&log->relay.lock);
384 	INIT_WORK(&log->relay.flush_work, copy_debug_logs_work);
385 	log->relay.started = false;
386 }
387 
388 static int guc_log_relay_create(struct intel_guc_log *log)
389 {
390 	struct intel_guc *guc = log_to_guc(log);
391 	struct drm_i915_private *dev_priv = guc_to_gt(guc)->i915;
392 	struct rchan *guc_log_relay_chan;
393 	size_t n_subbufs, subbuf_size;
394 	int ret;
395 
396 	lockdep_assert_held(&log->relay.lock);
397 	GEM_BUG_ON(!log->vma);
398 
399 	 /*
400 	  * Keep the size of sub buffers same as shared log buffer
401 	  * but GuC log-events excludes the error-state-capture logs
402 	  */
403 	subbuf_size = log->vma->size - CAPTURE_BUFFER_SIZE;
404 
405 	/*
406 	 * Store up to 8 snapshots, which is large enough to buffer sufficient
407 	 * boot time logs and provides enough leeway to User, in terms of
408 	 * latency, for consuming the logs from relay. Also doesn't take
409 	 * up too much memory.
410 	 */
411 	n_subbufs = 8;
412 
413 	guc_log_relay_chan = relay_open("guc_log",
414 					dev_priv->drm.primary->debugfs_root,
415 					subbuf_size, n_subbufs,
416 					&relay_callbacks, dev_priv);
417 	if (!guc_log_relay_chan) {
418 		DRM_ERROR("Couldn't create relay chan for GuC logging\n");
419 
420 		ret = -ENOMEM;
421 		return ret;
422 	}
423 
424 	GEM_BUG_ON(guc_log_relay_chan->subbuf_size < subbuf_size);
425 	log->relay.channel = guc_log_relay_chan;
426 
427 	return 0;
428 }
429 
430 static void guc_log_relay_destroy(struct intel_guc_log *log)
431 {
432 	lockdep_assert_held(&log->relay.lock);
433 
434 	relay_close(log->relay.channel);
435 	log->relay.channel = NULL;
436 }
437 
438 static void guc_log_copy_debuglogs_for_relay(struct intel_guc_log *log)
439 {
440 	struct intel_guc *guc = log_to_guc(log);
441 	struct drm_i915_private *dev_priv = guc_to_gt(guc)->i915;
442 	intel_wakeref_t wakeref;
443 
444 	_guc_log_copy_debuglogs_for_relay(log);
445 
446 	/*
447 	 * Generally device is expected to be active only at this
448 	 * time, so get/put should be really quick.
449 	 */
450 	with_intel_runtime_pm(&dev_priv->runtime_pm, wakeref)
451 		guc_action_flush_log_complete(guc);
452 }
453 
454 static u32 __get_default_log_level(struct intel_guc_log *log)
455 {
456 	struct intel_guc *guc = log_to_guc(log);
457 	struct drm_i915_private *i915 = guc_to_gt(guc)->i915;
458 
459 	/* A negative value means "use platform/config default" */
460 	if (i915->params.guc_log_level < 0) {
461 		return (IS_ENABLED(CONFIG_DRM_I915_DEBUG) ||
462 			IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)) ?
463 			GUC_LOG_LEVEL_MAX : GUC_LOG_LEVEL_NON_VERBOSE;
464 	}
465 
466 	if (i915->params.guc_log_level > GUC_LOG_LEVEL_MAX) {
467 		DRM_WARN("Incompatible option detected: %s=%d, %s!\n",
468 			 "guc_log_level", i915->params.guc_log_level,
469 			 "verbosity too high");
470 		return (IS_ENABLED(CONFIG_DRM_I915_DEBUG) ||
471 			IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)) ?
472 			GUC_LOG_LEVEL_MAX : GUC_LOG_LEVEL_DISABLED;
473 	}
474 
475 	GEM_BUG_ON(i915->params.guc_log_level < GUC_LOG_LEVEL_DISABLED);
476 	GEM_BUG_ON(i915->params.guc_log_level > GUC_LOG_LEVEL_MAX);
477 	return i915->params.guc_log_level;
478 }
479 
480 int intel_guc_log_create(struct intel_guc_log *log)
481 {
482 	struct intel_guc *guc = log_to_guc(log);
483 	struct i915_vma *vma;
484 	void *vaddr;
485 	u32 guc_log_size;
486 	int ret;
487 
488 	GEM_BUG_ON(log->vma);
489 
490 	guc_log_size = intel_guc_log_size(log);
491 
492 	vma = intel_guc_allocate_vma(guc, guc_log_size);
493 	if (IS_ERR(vma)) {
494 		ret = PTR_ERR(vma);
495 		goto err;
496 	}
497 
498 	log->vma = vma;
499 	/*
500 	 * Create a WC (Uncached for read) vmalloc mapping up front immediate access to
501 	 * data from memory during  critical events such as error capture
502 	 */
503 	vaddr = i915_gem_object_pin_map_unlocked(log->vma->obj, I915_MAP_WC);
504 	if (IS_ERR(vaddr)) {
505 		ret = PTR_ERR(vaddr);
506 		i915_vma_unpin_and_release(&log->vma, 0);
507 		goto err;
508 	}
509 	log->buf_addr = vaddr;
510 
511 	log->level = __get_default_log_level(log);
512 	DRM_DEBUG_DRIVER("guc_log_level=%d (%s, verbose:%s, verbosity:%d)\n",
513 			 log->level, str_enabled_disabled(log->level),
514 			 str_yes_no(GUC_LOG_LEVEL_IS_VERBOSE(log->level)),
515 			 GUC_LOG_LEVEL_TO_VERBOSITY(log->level));
516 
517 	return 0;
518 
519 err:
520 	DRM_ERROR("Failed to allocate or map GuC log buffer. %d\n", ret);
521 	return ret;
522 }
523 
524 void intel_guc_log_destroy(struct intel_guc_log *log)
525 {
526 	log->buf_addr = NULL;
527 	i915_vma_unpin_and_release(&log->vma, I915_VMA_RELEASE_MAP);
528 }
529 
530 int intel_guc_log_set_level(struct intel_guc_log *log, u32 level)
531 {
532 	struct intel_guc *guc = log_to_guc(log);
533 	struct drm_i915_private *dev_priv = guc_to_gt(guc)->i915;
534 	intel_wakeref_t wakeref;
535 	int ret = 0;
536 
537 	BUILD_BUG_ON(GUC_LOG_VERBOSITY_MIN != 0);
538 	GEM_BUG_ON(!log->vma);
539 
540 	/*
541 	 * GuC is recognizing log levels starting from 0 to max, we're using 0
542 	 * as indication that logging should be disabled.
543 	 */
544 	if (level < GUC_LOG_LEVEL_DISABLED || level > GUC_LOG_LEVEL_MAX)
545 		return -EINVAL;
546 
547 	mutex_lock(&dev_priv->drm.struct_mutex);
548 
549 	if (log->level == level)
550 		goto out_unlock;
551 
552 	with_intel_runtime_pm(&dev_priv->runtime_pm, wakeref)
553 		ret = guc_action_control_log(guc,
554 					     GUC_LOG_LEVEL_IS_VERBOSE(level),
555 					     GUC_LOG_LEVEL_IS_ENABLED(level),
556 					     GUC_LOG_LEVEL_TO_VERBOSITY(level));
557 	if (ret) {
558 		DRM_DEBUG_DRIVER("guc_log_control action failed %d\n", ret);
559 		goto out_unlock;
560 	}
561 
562 	log->level = level;
563 
564 out_unlock:
565 	mutex_unlock(&dev_priv->drm.struct_mutex);
566 
567 	return ret;
568 }
569 
570 bool intel_guc_log_relay_created(const struct intel_guc_log *log)
571 {
572 	return log->buf_addr;
573 }
574 
575 int intel_guc_log_relay_open(struct intel_guc_log *log)
576 {
577 	int ret;
578 
579 	if (!log->vma)
580 		return -ENODEV;
581 
582 	mutex_lock(&log->relay.lock);
583 
584 	if (intel_guc_log_relay_created(log)) {
585 		ret = -EEXIST;
586 		goto out_unlock;
587 	}
588 
589 	/*
590 	 * We require SSE 4.1 for fast reads from the GuC log buffer and
591 	 * it should be present on the chipsets supporting GuC based
592 	 * submissions.
593 	 */
594 	if (!i915_has_memcpy_from_wc()) {
595 		ret = -ENXIO;
596 		goto out_unlock;
597 	}
598 
599 	ret = guc_log_relay_create(log);
600 	if (ret)
601 		goto out_unlock;
602 
603 	ret = guc_log_relay_map(log);
604 	if (ret)
605 		goto out_relay;
606 
607 	mutex_unlock(&log->relay.lock);
608 
609 	return 0;
610 
611 out_relay:
612 	guc_log_relay_destroy(log);
613 out_unlock:
614 	mutex_unlock(&log->relay.lock);
615 
616 	return ret;
617 }
618 
619 int intel_guc_log_relay_start(struct intel_guc_log *log)
620 {
621 	if (log->relay.started)
622 		return -EEXIST;
623 
624 	/*
625 	 * When GuC is logging without us relaying to userspace, we're ignoring
626 	 * the flush notification. This means that we need to unconditionally
627 	 * flush on relay enabling, since GuC only notifies us once.
628 	 */
629 	queue_work(system_highpri_wq, &log->relay.flush_work);
630 
631 	log->relay.started = true;
632 
633 	return 0;
634 }
635 
636 void intel_guc_log_relay_flush(struct intel_guc_log *log)
637 {
638 	struct intel_guc *guc = log_to_guc(log);
639 	intel_wakeref_t wakeref;
640 
641 	if (!log->relay.started)
642 		return;
643 
644 	/*
645 	 * Before initiating the forceful flush, wait for any pending/ongoing
646 	 * flush to complete otherwise forceful flush may not actually happen.
647 	 */
648 	flush_work(&log->relay.flush_work);
649 
650 	with_intel_runtime_pm(guc_to_gt(guc)->uncore->rpm, wakeref)
651 		guc_action_flush_log(guc);
652 
653 	/* GuC would have updated log buffer by now, so copy it */
654 	guc_log_copy_debuglogs_for_relay(log);
655 }
656 
657 /*
658  * Stops the relay log. Called from intel_guc_log_relay_close(), so no
659  * possibility of race with start/flush since relay_write cannot race
660  * relay_close.
661  */
662 static void guc_log_relay_stop(struct intel_guc_log *log)
663 {
664 	struct intel_guc *guc = log_to_guc(log);
665 	struct drm_i915_private *i915 = guc_to_gt(guc)->i915;
666 
667 	if (!log->relay.started)
668 		return;
669 
670 	intel_synchronize_irq(i915);
671 
672 	flush_work(&log->relay.flush_work);
673 
674 	log->relay.started = false;
675 }
676 
677 void intel_guc_log_relay_close(struct intel_guc_log *log)
678 {
679 	guc_log_relay_stop(log);
680 
681 	mutex_lock(&log->relay.lock);
682 	GEM_BUG_ON(!intel_guc_log_relay_created(log));
683 	guc_log_relay_unmap(log);
684 	guc_log_relay_destroy(log);
685 	mutex_unlock(&log->relay.lock);
686 }
687 
688 void intel_guc_log_handle_flush_event(struct intel_guc_log *log)
689 {
690 	if (log->relay.started)
691 		queue_work(system_highpri_wq, &log->relay.flush_work);
692 }
693 
694 static const char *
695 stringify_guc_log_type(enum guc_log_buffer_type type)
696 {
697 	switch (type) {
698 	case GUC_DEBUG_LOG_BUFFER:
699 		return "DEBUG";
700 	case GUC_CRASH_DUMP_LOG_BUFFER:
701 		return "CRASH";
702 	case GUC_CAPTURE_LOG_BUFFER:
703 		return "CAPTURE";
704 	default:
705 		MISSING_CASE(type);
706 	}
707 
708 	return "";
709 }
710 
711 /**
712  * intel_guc_log_info - dump information about GuC log relay
713  * @log: the GuC log
714  * @p: the &drm_printer
715  *
716  * Pretty printer for GuC log info
717  */
718 void intel_guc_log_info(struct intel_guc_log *log, struct drm_printer *p)
719 {
720 	enum guc_log_buffer_type type;
721 
722 	if (!intel_guc_log_relay_created(log)) {
723 		drm_puts(p, "GuC log relay not created\n");
724 		return;
725 	}
726 
727 	drm_puts(p, "GuC logging stats:\n");
728 
729 	drm_printf(p, "\tRelay full count: %u\n", log->relay.full_count);
730 
731 	for (type = GUC_DEBUG_LOG_BUFFER; type < GUC_MAX_LOG_BUFFER; type++) {
732 		drm_printf(p, "\t%s:\tflush count %10u, overflow count %10u\n",
733 			   stringify_guc_log_type(type),
734 			   log->stats[type].flush,
735 			   log->stats[type].sampled_overflow);
736 	}
737 }
738 
739 /**
740  * intel_guc_log_dump - dump the contents of the GuC log
741  * @log: the GuC log
742  * @p: the &drm_printer
743  * @dump_load_err: dump the log saved on GuC load error
744  *
745  * Pretty printer for the GuC log
746  */
747 int intel_guc_log_dump(struct intel_guc_log *log, struct drm_printer *p,
748 		       bool dump_load_err)
749 {
750 	struct intel_guc *guc = log_to_guc(log);
751 	struct intel_uc *uc = container_of(guc, struct intel_uc, guc);
752 	struct drm_i915_gem_object *obj = NULL;
753 	void *map;
754 	u32 *page;
755 	int i, j;
756 
757 	if (!intel_guc_is_supported(guc))
758 		return -ENODEV;
759 
760 	if (dump_load_err)
761 		obj = uc->load_err_log;
762 	else if (guc->log.vma)
763 		obj = guc->log.vma->obj;
764 
765 	if (!obj)
766 		return 0;
767 
768 	page = (u32 *)__get_free_page(GFP_KERNEL);
769 	if (!page)
770 		return -ENOMEM;
771 
772 	intel_guc_dump_time_info(guc, p);
773 
774 	map = i915_gem_object_pin_map_unlocked(obj, I915_MAP_WC);
775 	if (IS_ERR(map)) {
776 		DRM_DEBUG("Failed to pin object\n");
777 		drm_puts(p, "(log data unaccessible)\n");
778 		free_page((unsigned long)page);
779 		return PTR_ERR(map);
780 	}
781 
782 	for (i = 0; i < obj->base.size; i += PAGE_SIZE) {
783 		if (!i915_memcpy_from_wc(page, map + i, PAGE_SIZE))
784 			memcpy(page, map + i, PAGE_SIZE);
785 
786 		for (j = 0; j < PAGE_SIZE / sizeof(u32); j += 4)
787 			drm_printf(p, "0x%08x 0x%08x 0x%08x 0x%08x\n",
788 				   *(page + j + 0), *(page + j + 1),
789 				   *(page + j + 2), *(page + j + 3));
790 	}
791 
792 	drm_puts(p, "\n");
793 
794 	i915_gem_object_unpin_map(obj);
795 	free_page((unsigned long)page);
796 
797 	return 0;
798 }
799