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      1 /*	$NetBSD: amdgpu_fence.c,v 1.11 2023/07/20 18:02:45 mrg Exp $	*/
      2 
      3 /*
      4  * Copyright 2009 Jerome Glisse.
      5  * All Rights Reserved.
      6  *
      7  * Permission is hereby granted, free of charge, to any person obtaining a
      8  * copy of this software and associated documentation files (the
      9  * "Software"), to deal in the Software without restriction, including
     10  * without limitation the rights to use, copy, modify, merge, publish,
     11  * distribute, sub license, and/or sell copies of the Software, and to
     12  * permit persons to whom the Software is furnished to do so, subject to
     13  * the following conditions:
     14  *
     15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     17  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
     18  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
     19  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
     20  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
     21  * USE OR OTHER DEALINGS IN THE SOFTWARE.
     22  *
     23  * The above copyright notice and this permission notice (including the
     24  * next paragraph) shall be included in all copies or substantial portions
     25  * of the Software.
     26  *
     27  */
     28 /*
     29  * Authors:
     30  *    Jerome Glisse <glisse (at) freedesktop.org>
     31  *    Dave Airlie
     32  */
     33 #include <sys/cdefs.h>
     34 __KERNEL_RCSID(0, "$NetBSD: amdgpu_fence.c,v 1.11 2023/07/20 18:02:45 mrg Exp $");
     35 
     36 #include <linux/seq_file.h>
     37 #include <linux/atomic.h>
     38 #include <linux/wait.h>
     39 #include <linux/kref.h>
     40 #include <linux/slab.h>
     41 #include <linux/firmware.h>
     42 #include <linux/pm_runtime.h>
     43 
     44 #include <drm/drm_debugfs.h>
     45 
     46 #include "amdgpu.h"
     47 #include "amdgpu_trace.h"
     48 
     49 #include <linux/nbsd-namespace.h>
     50 
     51 /*
     52  * Fences
     53  * Fences mark an event in the GPUs pipeline and are used
     54  * for GPU/CPU synchronization.  When the fence is written,
     55  * it is expected that all buffers associated with that fence
     56  * are no longer in use by the associated ring on the GPU and
     57  * that the the relevant GPU caches have been flushed.
     58  */
     59 
     60 struct amdgpu_fence {
     61 	struct dma_fence base;
     62 
     63 	/* RB, DMA, etc. */
     64 	struct amdgpu_ring		*ring;
     65 };
     66 
     67 static struct kmem_cache *amdgpu_fence_slab;
     68 
     69 int amdgpu_fence_slab_init(void)
     70 {
     71 	amdgpu_fence_slab = kmem_cache_create(
     72 		"amdgpu_fence", sizeof(struct amdgpu_fence), 0,
     73 		SLAB_HWCACHE_ALIGN, NULL);
     74 	if (!amdgpu_fence_slab)
     75 		return -ENOMEM;
     76 	return 0;
     77 }
     78 
     79 void amdgpu_fence_slab_fini(void)
     80 {
     81 	rcu_barrier();
     82 	kmem_cache_destroy(amdgpu_fence_slab);
     83 }
     84 /*
     85  * Cast helper
     86  */
     87 static const struct dma_fence_ops amdgpu_fence_ops;
     88 static inline struct amdgpu_fence *to_amdgpu_fence(struct dma_fence *f)
     89 {
     90 	struct amdgpu_fence *__f = container_of(f, struct amdgpu_fence, base);
     91 
     92 	if (__f->base.ops == &amdgpu_fence_ops)
     93 		return __f;
     94 
     95 	return NULL;
     96 }
     97 
     98 /**
     99  * amdgpu_fence_write - write a fence value
    100  *
    101  * @ring: ring the fence is associated with
    102  * @seq: sequence number to write
    103  *
    104  * Writes a fence value to memory (all asics).
    105  */
    106 static void amdgpu_fence_write(struct amdgpu_ring *ring, u32 seq)
    107 {
    108 	struct amdgpu_fence_driver *drv = &ring->fence_drv;
    109 
    110 	if (drv->cpu_addr)
    111 		*drv->cpu_addr = cpu_to_le32(seq);
    112 }
    113 
    114 /**
    115  * amdgpu_fence_read - read a fence value
    116  *
    117  * @ring: ring the fence is associated with
    118  *
    119  * Reads a fence value from memory (all asics).
    120  * Returns the value of the fence read from memory.
    121  */
    122 static u32 amdgpu_fence_read(struct amdgpu_ring *ring)
    123 {
    124 	struct amdgpu_fence_driver *drv = &ring->fence_drv;
    125 	u32 seq = 0;
    126 
    127 	if (drv->cpu_addr)
    128 		seq = le32_to_cpu(*drv->cpu_addr);
    129 	else
    130 		seq = atomic_read(&drv->last_seq);
    131 
    132 	return seq;
    133 }
    134 
    135 /**
    136  * amdgpu_fence_emit - emit a fence on the requested ring
    137  *
    138  * @ring: ring the fence is associated with
    139  * @f: resulting fence object
    140  *
    141  * Emits a fence command on the requested ring (all asics).
    142  * Returns 0 on success, -ENOMEM on failure.
    143  */
    144 int amdgpu_fence_emit(struct amdgpu_ring *ring, struct dma_fence **f,
    145 		      unsigned flags)
    146 {
    147 	struct amdgpu_device *adev = ring->adev;
    148 	struct amdgpu_fence *fence;
    149 	struct dma_fence __rcu **ptr;
    150 	uint32_t seq;
    151 	int r;
    152 
    153 	fence = kmem_cache_alloc(amdgpu_fence_slab, GFP_KERNEL);
    154 	if (fence == NULL)
    155 		return -ENOMEM;
    156 
    157 	seq = ++ring->fence_drv.sync_seq;
    158 	fence->ring = ring;
    159 	dma_fence_init(&fence->base, &amdgpu_fence_ops,
    160 		       &ring->fence_drv.lock,
    161 		       adev->fence_context + ring->idx,
    162 		       seq);
    163 	amdgpu_ring_emit_fence(ring, ring->fence_drv.gpu_addr,
    164 			       seq, flags | AMDGPU_FENCE_FLAG_INT);
    165 	pm_runtime_get_noresume(adev->ddev->dev);
    166 	ptr = &ring->fence_drv.fences[seq & ring->fence_drv.num_fences_mask];
    167 	if (unlikely(rcu_dereference_protected(*ptr, 1))) {
    168 		struct dma_fence *old;
    169 
    170 		rcu_read_lock();
    171 		old = dma_fence_get_rcu_safe(ptr);
    172 		rcu_read_unlock();
    173 
    174 		if (old) {
    175 			r = dma_fence_wait(old, false);
    176 			dma_fence_put(old);
    177 			if (r)
    178 				return r;
    179 		}
    180 	}
    181 
    182 	/* This function can't be called concurrently anyway, otherwise
    183 	 * emitting the fence would mess up the hardware ring buffer.
    184 	 */
    185 	rcu_assign_pointer(*ptr, dma_fence_get(&fence->base));
    186 
    187 	*f = &fence->base;
    188 
    189 	return 0;
    190 }
    191 
    192 /**
    193  * amdgpu_fence_emit_polling - emit a fence on the requeste ring
    194  *
    195  * @ring: ring the fence is associated with
    196  * @s: resulting sequence number
    197  *
    198  * Emits a fence command on the requested ring (all asics).
    199  * Used For polling fence.
    200  * Returns 0 on success, -ENOMEM on failure.
    201  */
    202 int amdgpu_fence_emit_polling(struct amdgpu_ring *ring, uint32_t *s)
    203 {
    204 	uint32_t seq;
    205 
    206 	if (!s)
    207 		return -EINVAL;
    208 
    209 	seq = ++ring->fence_drv.sync_seq;
    210 	amdgpu_ring_emit_fence(ring, ring->fence_drv.gpu_addr,
    211 			       seq, 0);
    212 
    213 	*s = seq;
    214 
    215 	return 0;
    216 }
    217 
    218 /**
    219  * amdgpu_fence_schedule_fallback - schedule fallback check
    220  *
    221  * @ring: pointer to struct amdgpu_ring
    222  *
    223  * Start a timer as fallback to our interrupts.
    224  */
    225 static void amdgpu_fence_schedule_fallback(struct amdgpu_ring *ring)
    226 {
    227 	mod_timer(&ring->fence_drv.fallback_timer,
    228 		  jiffies + AMDGPU_FENCE_JIFFIES_TIMEOUT);
    229 }
    230 
    231 /**
    232  * amdgpu_fence_process - check for fence activity
    233  *
    234  * @ring: pointer to struct amdgpu_ring
    235  *
    236  * Checks the current fence value and calculates the last
    237  * signalled fence value. Wakes the fence queue if the
    238  * sequence number has increased.
    239  *
    240  * Returns true if fence was processed
    241  */
    242 bool amdgpu_fence_process(struct amdgpu_ring *ring)
    243 {
    244 	struct amdgpu_fence_driver *drv = &ring->fence_drv;
    245 	struct amdgpu_device *adev = ring->adev;
    246 	uint32_t seq, last_seq;
    247 	int r;
    248 
    249 	do {
    250 		last_seq = atomic_read(&ring->fence_drv.last_seq);
    251 		seq = amdgpu_fence_read(ring);
    252 
    253 	} while (atomic_cmpxchg(&drv->last_seq, last_seq, seq) != last_seq);
    254 
    255 	if (del_timer(&ring->fence_drv.fallback_timer) &&
    256 	    seq != ring->fence_drv.sync_seq)
    257 		amdgpu_fence_schedule_fallback(ring);
    258 
    259 	if (unlikely(seq == last_seq))
    260 		return false;
    261 
    262 	last_seq &= drv->num_fences_mask;
    263 	seq &= drv->num_fences_mask;
    264 
    265 	do {
    266 		struct dma_fence *fence, **ptr;
    267 
    268 		++last_seq;
    269 		last_seq &= drv->num_fences_mask;
    270 		ptr = &drv->fences[last_seq];
    271 
    272 		/* There is always exactly one thread signaling this fence slot */
    273 		fence = rcu_dereference_protected(*ptr, 1);
    274 		RCU_INIT_POINTER(*ptr, NULL);
    275 
    276 		if (!fence)
    277 			continue;
    278 
    279 		r = dma_fence_signal(fence);
    280 		if (!r)
    281 			DMA_FENCE_TRACE(fence, "signaled from irq context\n");
    282 		else
    283 			BUG();
    284 
    285 		dma_fence_put(fence);
    286 		pm_runtime_mark_last_busy(adev->ddev->dev);
    287 		pm_runtime_put_autosuspend(adev->ddev->dev);
    288 	} while (last_seq != seq);
    289 
    290 	return true;
    291 }
    292 
    293 /**
    294  * amdgpu_fence_fallback - fallback for hardware interrupts
    295  *
    296  * @work: delayed work item
    297  *
    298  * Checks for fence activity.
    299  */
    300 static void amdgpu_fence_fallback(struct timer_list *t)
    301 {
    302 	struct amdgpu_ring *ring = from_timer(ring, t,
    303 					      fence_drv.fallback_timer);
    304 
    305 	if (amdgpu_fence_process(ring))
    306 		DRM_WARN("Fence fallback timer expired on ring %s\n", ring->name);
    307 }
    308 
    309 /**
    310  * amdgpu_fence_wait_empty - wait for all fences to signal
    311  *
    312  * @adev: amdgpu device pointer
    313  * @ring: ring index the fence is associated with
    314  *
    315  * Wait for all fences on the requested ring to signal (all asics).
    316  * Returns 0 if the fences have passed, error for all other cases.
    317  */
    318 int amdgpu_fence_wait_empty(struct amdgpu_ring *ring)
    319 {
    320 	uint64_t seq = READ_ONCE(ring->fence_drv.sync_seq);
    321 	struct dma_fence *fence, **ptr;
    322 	int r;
    323 
    324 	if (!seq)
    325 		return 0;
    326 
    327 	ptr = &ring->fence_drv.fences[seq & ring->fence_drv.num_fences_mask];
    328 	rcu_read_lock();
    329 	fence = rcu_dereference(*ptr);
    330 	if (!fence || !dma_fence_get_rcu(fence)) {
    331 		rcu_read_unlock();
    332 		return 0;
    333 	}
    334 	rcu_read_unlock();
    335 
    336 	r = dma_fence_wait(fence, false);
    337 	dma_fence_put(fence);
    338 	return r;
    339 }
    340 
    341 /**
    342  * amdgpu_fence_wait_polling - busy wait for givn sequence number
    343  *
    344  * @ring: ring index the fence is associated with
    345  * @wait_seq: sequence number to wait
    346  * @timeout: the timeout for waiting in usecs
    347  *
    348  * Wait for all fences on the requested ring to signal (all asics).
    349  * Returns left time if no timeout, 0 or minus if timeout.
    350  */
    351 signed long amdgpu_fence_wait_polling(struct amdgpu_ring *ring,
    352 				      uint32_t wait_seq,
    353 				      signed long timeout)
    354 {
    355 	uint32_t seq;
    356 
    357 	do {
    358 		seq = amdgpu_fence_read(ring);
    359 		udelay(5);
    360 		timeout -= 5;
    361 	} while ((int32_t)(wait_seq - seq) > 0 && timeout > 0);
    362 
    363 	return timeout > 0 ? timeout : 0;
    364 }
    365 /**
    366  * amdgpu_fence_count_emitted - get the count of emitted fences
    367  *
    368  * @ring: ring the fence is associated with
    369  *
    370  * Get the number of fences emitted on the requested ring (all asics).
    371  * Returns the number of emitted fences on the ring.  Used by the
    372  * dynpm code to ring track activity.
    373  */
    374 unsigned amdgpu_fence_count_emitted(struct amdgpu_ring *ring)
    375 {
    376 	uint64_t emitted;
    377 
    378 	/* We are not protected by ring lock when reading the last sequence
    379 	 * but it's ok to report slightly wrong fence count here.
    380 	 */
    381 	amdgpu_fence_process(ring);
    382 	emitted = 0x100000000ull;
    383 	emitted -= atomic_read(&ring->fence_drv.last_seq);
    384 	emitted += READ_ONCE(ring->fence_drv.sync_seq);
    385 	return lower_32_bits(emitted);
    386 }
    387 
    388 /**
    389  * amdgpu_fence_driver_start_ring - make the fence driver
    390  * ready for use on the requested ring.
    391  *
    392  * @ring: ring to start the fence driver on
    393  * @irq_src: interrupt source to use for this ring
    394  * @irq_type: interrupt type to use for this ring
    395  *
    396  * Make the fence driver ready for processing (all asics).
    397  * Not all asics have all rings, so each asic will only
    398  * start the fence driver on the rings it has.
    399  * Returns 0 for success, errors for failure.
    400  */
    401 int amdgpu_fence_driver_start_ring(struct amdgpu_ring *ring,
    402 				   struct amdgpu_irq_src *irq_src,
    403 				   unsigned irq_type)
    404 {
    405 	struct amdgpu_device *adev = ring->adev;
    406 	uint64_t index;
    407 
    408 	if (ring->funcs->type != AMDGPU_RING_TYPE_UVD) {
    409 		ring->fence_drv.cpu_addr = &adev->wb.wb[ring->fence_offs];
    410 		ring->fence_drv.gpu_addr = adev->wb.gpu_addr + (ring->fence_offs * 4);
    411 	} else {
    412 		/* put fence directly behind firmware */
    413 		index = ALIGN(adev->uvd.fw->size, 8);
    414 		ring->fence_drv.cpu_addr = adev->uvd.inst[ring->me].cpu_addr + index;
    415 		ring->fence_drv.gpu_addr = adev->uvd.inst[ring->me].gpu_addr + index;
    416 	}
    417 	amdgpu_fence_write(ring, atomic_read(&ring->fence_drv.last_seq));
    418 	amdgpu_irq_get(adev, irq_src, irq_type);
    419 
    420 	ring->fence_drv.irq_src = irq_src;
    421 	ring->fence_drv.irq_type = irq_type;
    422 	ring->fence_drv.initialized = true;
    423 
    424 	DRM_DEV_DEBUG(adev->dev, "fence driver on ring %s use gpu addr "
    425 		      "0x%016"PRIx64", cpu addr 0x%p\n", ring->name,
    426 		      ring->fence_drv.gpu_addr, ring->fence_drv.cpu_addr);
    427 	return 0;
    428 }
    429 
    430 /**
    431  * amdgpu_fence_driver_init_ring - init the fence driver
    432  * for the requested ring.
    433  *
    434  * @ring: ring to init the fence driver on
    435  * @num_hw_submission: number of entries on the hardware queue
    436  *
    437  * Init the fence driver for the requested ring (all asics).
    438  * Helper function for amdgpu_fence_driver_init().
    439  */
    440 int amdgpu_fence_driver_init_ring(struct amdgpu_ring *ring,
    441 				  unsigned num_hw_submission)
    442 {
    443 	struct amdgpu_device *adev = ring->adev;
    444 	long timeout;
    445 	int r;
    446 
    447 	if (!adev)
    448 		return -EINVAL;
    449 
    450 	/* Check that num_hw_submission is a power of two */
    451 	if ((num_hw_submission & (num_hw_submission - 1)) != 0)
    452 		return -EINVAL;
    453 
    454 	ring->fence_drv.cpu_addr = NULL;
    455 	ring->fence_drv.gpu_addr = 0;
    456 	ring->fence_drv.sync_seq = 0;
    457 	atomic_set(&ring->fence_drv.last_seq, 0);
    458 	ring->fence_drv.initialized = false;
    459 
    460 	timer_setup(&ring->fence_drv.fallback_timer, amdgpu_fence_fallback, 0);
    461 
    462 	ring->fence_drv.num_fences_mask = num_hw_submission * 2 - 1;
    463 	spin_lock_init(&ring->fence_drv.lock);
    464 	ring->fence_drv.fences = kcalloc(num_hw_submission * 2, sizeof(void *),
    465 					 GFP_KERNEL);
    466 	if (!ring->fence_drv.fences)
    467 		return -ENOMEM;
    468 
    469 	/* No need to setup the GPU scheduler for KIQ ring */
    470 	if (ring->funcs->type != AMDGPU_RING_TYPE_KIQ) {
    471 		switch (ring->funcs->type) {
    472 		case AMDGPU_RING_TYPE_GFX:
    473 			timeout = adev->gfx_timeout;
    474 			break;
    475 		case AMDGPU_RING_TYPE_COMPUTE:
    476 			timeout = adev->compute_timeout;
    477 			break;
    478 		case AMDGPU_RING_TYPE_SDMA:
    479 			timeout = adev->sdma_timeout;
    480 			break;
    481 		default:
    482 			timeout = adev->video_timeout;
    483 			break;
    484 		}
    485 
    486 		r = drm_sched_init(&ring->sched, &amdgpu_sched_ops,
    487 				   num_hw_submission, amdgpu_job_hang_limit,
    488 				   timeout, ring->name);
    489 		if (r) {
    490 			DRM_ERROR("Failed to create scheduler on ring %s.\n",
    491 				  ring->name);
    492 			return r;
    493 		}
    494 	}
    495 
    496 	return 0;
    497 }
    498 
    499 /**
    500  * amdgpu_fence_driver_init - init the fence driver
    501  * for all possible rings.
    502  *
    503  * @adev: amdgpu device pointer
    504  *
    505  * Init the fence driver for all possible rings (all asics).
    506  * Not all asics have all rings, so each asic will only
    507  * start the fence driver on the rings it has using
    508  * amdgpu_fence_driver_start_ring().
    509  * Returns 0 for success.
    510  */
    511 int amdgpu_fence_driver_init(struct amdgpu_device *adev)
    512 {
    513 	if (amdgpu_debugfs_fence_init(adev))
    514 		dev_err(adev->dev, "fence debugfs file creation failed\n");
    515 
    516 	return 0;
    517 }
    518 
    519 /**
    520  * amdgpu_fence_driver_fini - tear down the fence driver
    521  * for all possible rings.
    522  *
    523  * @adev: amdgpu device pointer
    524  *
    525  * Tear down the fence driver for all possible rings (all asics).
    526  */
    527 void amdgpu_fence_driver_fini(struct amdgpu_device *adev)
    528 {
    529 	unsigned i, j;
    530 	int r;
    531 
    532 	for (i = 0; i < AMDGPU_MAX_RINGS; i++) {
    533 		struct amdgpu_ring *ring = adev->rings[i];
    534 
    535 		if (!ring || !ring->fence_drv.initialized)
    536 			continue;
    537 		r = amdgpu_fence_wait_empty(ring);
    538 		if (r) {
    539 			/* no need to trigger GPU reset as we are unloading */
    540 			amdgpu_fence_driver_force_completion(ring);
    541 		}
    542 		amdgpu_irq_put(adev, ring->fence_drv.irq_src,
    543 			       ring->fence_drv.irq_type);
    544 		if (ring->funcs->type != AMDGPU_RING_TYPE_KIQ) {
    545 			drm_sched_fini(&ring->sched);
    546 		}
    547 		del_timer_sync(&ring->fence_drv.fallback_timer);
    548 		for (j = 0; j <= ring->fence_drv.num_fences_mask; ++j)
    549 			dma_fence_put(ring->fence_drv.fences[j]);
    550 		kfree(ring->fence_drv.fences);
    551 		ring->fence_drv.fences = NULL;
    552 		ring->fence_drv.initialized = false;
    553 		spin_lock_destroy(&ring->fence_drv.lock);
    554 	}
    555 }
    556 
    557 /**
    558  * amdgpu_fence_driver_suspend - suspend the fence driver
    559  * for all possible rings.
    560  *
    561  * @adev: amdgpu device pointer
    562  *
    563  * Suspend the fence driver for all possible rings (all asics).
    564  */
    565 void amdgpu_fence_driver_suspend(struct amdgpu_device *adev)
    566 {
    567 	int i, r;
    568 
    569 	for (i = 0; i < AMDGPU_MAX_RINGS; i++) {
    570 		struct amdgpu_ring *ring = adev->rings[i];
    571 		if (!ring || !ring->fence_drv.initialized)
    572 			continue;
    573 
    574 		/* wait for gpu to finish processing current batch */
    575 		r = amdgpu_fence_wait_empty(ring);
    576 		if (r) {
    577 			/* delay GPU reset to resume */
    578 			amdgpu_fence_driver_force_completion(ring);
    579 		}
    580 
    581 		/* disable the interrupt */
    582 		amdgpu_irq_put(adev, ring->fence_drv.irq_src,
    583 			       ring->fence_drv.irq_type);
    584 	}
    585 }
    586 
    587 /**
    588  * amdgpu_fence_driver_resume - resume the fence driver
    589  * for all possible rings.
    590  *
    591  * @adev: amdgpu device pointer
    592  *
    593  * Resume the fence driver for all possible rings (all asics).
    594  * Not all asics have all rings, so each asic will only
    595  * start the fence driver on the rings it has using
    596  * amdgpu_fence_driver_start_ring().
    597  * Returns 0 for success.
    598  */
    599 void amdgpu_fence_driver_resume(struct amdgpu_device *adev)
    600 {
    601 	int i;
    602 
    603 	for (i = 0; i < AMDGPU_MAX_RINGS; i++) {
    604 		struct amdgpu_ring *ring = adev->rings[i];
    605 		if (!ring || !ring->fence_drv.initialized)
    606 			continue;
    607 
    608 		/* enable the interrupt */
    609 		amdgpu_irq_get(adev, ring->fence_drv.irq_src,
    610 			       ring->fence_drv.irq_type);
    611 	}
    612 }
    613 
    614 /**
    615  * amdgpu_fence_driver_force_completion - force signal latest fence of ring
    616  *
    617  * @ring: fence of the ring to signal
    618  *
    619  */
    620 void amdgpu_fence_driver_force_completion(struct amdgpu_ring *ring)
    621 {
    622 	amdgpu_fence_write(ring, ring->fence_drv.sync_seq);
    623 	amdgpu_fence_process(ring);
    624 }
    625 
    626 /*
    627  * Common fence implementation
    628  */
    629 
    630 static const char *amdgpu_fence_get_driver_name(struct dma_fence *fence)
    631 {
    632 	return "amdgpu";
    633 }
    634 
    635 static const char *amdgpu_fence_get_timeline_name(struct dma_fence *f)
    636 {
    637 	struct amdgpu_fence *fence = to_amdgpu_fence(f);
    638 	return (const char *)fence->ring->name;
    639 }
    640 
    641 /**
    642  * amdgpu_fence_enable_signaling - enable signalling on fence
    643  * @fence: fence
    644  *
    645  * This function is called with fence_queue lock held, and adds a callback
    646  * to fence_queue that checks if this fence is signaled, and if so it
    647  * signals the fence and removes itself.
    648  */
    649 static bool amdgpu_fence_enable_signaling(struct dma_fence *f)
    650 {
    651 	struct amdgpu_fence *fence = to_amdgpu_fence(f);
    652 	struct amdgpu_ring *ring = fence->ring;
    653 
    654 	if (!timer_pending(&ring->fence_drv.fallback_timer))
    655 		amdgpu_fence_schedule_fallback(ring);
    656 
    657 	DMA_FENCE_TRACE(&fence->base, "armed on ring %i!\n", ring->idx);
    658 
    659 	return true;
    660 }
    661 
    662 /**
    663  * amdgpu_fence_free - free up the fence memory
    664  *
    665  * @rcu: RCU callback head
    666  *
    667  * Free up the fence memory after the RCU grace period.
    668  */
    669 static void amdgpu_fence_free(struct rcu_head *rcu)
    670 {
    671 	struct dma_fence *f = container_of(rcu, struct dma_fence, rcu);
    672 	struct amdgpu_fence *fence = to_amdgpu_fence(f);
    673 	dma_fence_destroy(f);
    674 	kmem_cache_free(amdgpu_fence_slab, fence);
    675 }
    676 
    677 /**
    678  * amdgpu_fence_release - callback that fence can be freed
    679  *
    680  * @fence: fence
    681  *
    682  * This function is called when the reference count becomes zero.
    683  * It just RCU schedules freeing up the fence.
    684  */
    685 static void amdgpu_fence_release(struct dma_fence *f)
    686 {
    687 	call_rcu(&f->rcu, amdgpu_fence_free);
    688 }
    689 
    690 static const struct dma_fence_ops amdgpu_fence_ops = {
    691 	.get_driver_name = amdgpu_fence_get_driver_name,
    692 	.get_timeline_name = amdgpu_fence_get_timeline_name,
    693 	.enable_signaling = amdgpu_fence_enable_signaling,
    694 	.release = amdgpu_fence_release,
    695 };
    696 
    697 /*
    698  * Fence debugfs
    699  */
    700 #if defined(CONFIG_DEBUG_FS)
    701 static int amdgpu_debugfs_fence_info(struct seq_file *m, void *data)
    702 {
    703 	struct drm_info_node *node = (struct drm_info_node *)m->private;
    704 	struct drm_device *dev = node->minor->dev;
    705 	struct amdgpu_device *adev = dev->dev_private;
    706 	int i;
    707 
    708 	for (i = 0; i < AMDGPU_MAX_RINGS; ++i) {
    709 		struct amdgpu_ring *ring = adev->rings[i];
    710 		if (!ring || !ring->fence_drv.initialized)
    711 			continue;
    712 
    713 		amdgpu_fence_process(ring);
    714 
    715 		seq_printf(m, "--- ring %d (%s) ---\n", i, ring->name);
    716 		seq_printf(m, "Last signaled fence          0x%08x\n",
    717 			   atomic_read(&ring->fence_drv.last_seq));
    718 		seq_printf(m, "Last emitted                 0x%08x\n",
    719 			   ring->fence_drv.sync_seq);
    720 
    721 		if (ring->funcs->type == AMDGPU_RING_TYPE_GFX ||
    722 		    ring->funcs->type == AMDGPU_RING_TYPE_SDMA) {
    723 			seq_printf(m, "Last signaled trailing fence 0x%08x\n",
    724 				   le32_to_cpu(*ring->trail_fence_cpu_addr));
    725 			seq_printf(m, "Last emitted                 0x%08x\n",
    726 				   ring->trail_seq);
    727 		}
    728 
    729 		if (ring->funcs->type != AMDGPU_RING_TYPE_GFX)
    730 			continue;
    731 
    732 		/* set in CP_VMID_PREEMPT and preemption occurred */
    733 		seq_printf(m, "Last preempted               0x%08x\n",
    734 			   le32_to_cpu(*(ring->fence_drv.cpu_addr + 2)));
    735 		/* set in CP_VMID_RESET and reset occurred */
    736 		seq_printf(m, "Last reset                   0x%08x\n",
    737 			   le32_to_cpu(*(ring->fence_drv.cpu_addr + 4)));
    738 		/* Both preemption and reset occurred */
    739 		seq_printf(m, "Last both                    0x%08x\n",
    740 			   le32_to_cpu(*(ring->fence_drv.cpu_addr + 6)));
    741 	}
    742 	return 0;
    743 }
    744 
    745 /**
    746  * amdgpu_debugfs_gpu_recover - manually trigger a gpu reset & recover
    747  *
    748  * Manually trigger a gpu reset at the next fence wait.
    749  */
    750 static int amdgpu_debugfs_gpu_recover(struct seq_file *m, void *data)
    751 {
    752 	struct drm_info_node *node = (struct drm_info_node *) m->private;
    753 	struct drm_device *dev = node->minor->dev;
    754 	struct amdgpu_device *adev = dev->dev_private;
    755 	int r;
    756 
    757 	r = pm_runtime_get_sync(dev->dev);
    758 	if (r < 0)
    759 		return 0;
    760 
    761 	seq_printf(m, "gpu recover\n");
    762 	amdgpu_device_gpu_recover(adev, NULL);
    763 
    764 	pm_runtime_mark_last_busy(dev->dev);
    765 	pm_runtime_put_autosuspend(dev->dev);
    766 
    767 	return 0;
    768 }
    769 
    770 static const struct drm_info_list amdgpu_debugfs_fence_list[] = {
    771 	{"amdgpu_fence_info", &amdgpu_debugfs_fence_info, 0, NULL},
    772 	{"amdgpu_gpu_recover", &amdgpu_debugfs_gpu_recover, 0, NULL}
    773 };
    774 
    775 static const struct drm_info_list amdgpu_debugfs_fence_list_sriov[] = {
    776 	{"amdgpu_fence_info", &amdgpu_debugfs_fence_info, 0, NULL},
    777 };
    778 #endif
    779 
    780 int amdgpu_debugfs_fence_init(struct amdgpu_device *adev)
    781 {
    782 #if defined(CONFIG_DEBUG_FS)
    783 	if (amdgpu_sriov_vf(adev))
    784 		return amdgpu_debugfs_add_files(adev, amdgpu_debugfs_fence_list_sriov, 1);
    785 	return amdgpu_debugfs_add_files(adev, amdgpu_debugfs_fence_list, 2);
    786 #else
    787 	return 0;
    788 #endif
    789 }
    790 
    791