path: root/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c

/*
 * Copyright 2009 Jerome Glisse.
 * All Rights Reserved.
 *
 * 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, sub license, 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 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 NON-INFRINGEMENT. IN NO EVENT SHALL
 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS 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.
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 *
 */
/*
 * Authors:
 *    Jerome Glisse <glisse@freedesktop.org>
 *    Dave Airlie
 */
#include <linux/seq_file.h>
#include <linux/atomic.h>
#include <linux/wait.h>
#include <linux/kref.h>
#include <linux/slab.h>
#include <linux/firmware.h>
#include <drm/drmP.h>
#include "amdgpu.h"
#include "amdgpu_trace.h"

/*
 * Fences
 * Fences mark an event in the GPUs pipeline and are used
 * for GPU/CPU synchronization.  When the fence is written,
 * it is expected that all buffers associated with that fence
 * are no longer in use by the associated ring on the GPU and
 * that the the relevant GPU caches have been flushed.
 */

/**
 * amdgpu_fence_write - write a fence value
 *
 * @ring: ring the fence is associated with
 * @seq: sequence number to write
 *
 * Writes a fence value to memory (all asics).
 */
static void amdgpu_fence_write(struct amdgpu_ring *ring, u32 seq)
{
	struct amdgpu_fence_driver *drv = &ring->fence_drv;

	if (drv->cpu_addr)
		*drv->cpu_addr = cpu_to_le32(seq);
}

/**
 * amdgpu_fence_read - read a fence value
 *
 * @ring: ring the fence is associated with
 *
 * Reads a fence value from memory (all asics).
 * Returns the value of the fence read from memory.
 */
static u32 amdgpu_fence_read(struct amdgpu_ring *ring)
{
	struct amdgpu_fence_driver *drv = &ring->fence_drv;
	u32 seq = 0;

	if (drv->cpu_addr)
		seq = le32_to_cpu(*drv->cpu_addr);
	else
		seq = lower_32_bits(atomic64_read(&drv->last_seq));

	return seq;
}

/**
 * amdgpu_fence_schedule_check - schedule lockup check
 *
 * @ring: pointer to struct amdgpu_ring
 *
 * Queues a delayed work item to check for lockups.
 */
static void amdgpu_fence_schedule_check(struct amdgpu_ring *ring)
{
	/*
	 * Do not reset the timer here with mod_delayed_work,
	 * this can livelock in an interaction with TTM delayed destroy.
	 */
	queue_delayed_work(system_power_efficient_wq,
		&ring->fence_drv.lockup_work,
		AMDGPU_FENCE_JIFFIES_TIMEOUT);
}

/**
 * amdgpu_fence_emit - emit a fence on the requested ring
 *
 * @ring: ring the fence is associated with
 * @owner: creator of the fence
 * @fence: amdgpu fence object
 *
 * Emits a fence command on the requested ring (all asics).
 * Returns 0 on success, -ENOMEM on failure.
 */
int amdgpu_fence_emit(struct amdgpu_ring *ring, void *owner,
		      struct amdgpu_fence **fence)
{
	struct amdgpu_device *adev = ring->adev;

	/* we are protected by the ring emission mutex */
	*fence = kmalloc(sizeof(struct amdgpu_fence), GFP_KERNEL);
	if ((*fence) == NULL) {
		return -ENOMEM;
	}
	(*fence)->seq = ++ring->fence_drv.sync_seq[ring->idx];
	(*fence)->ring = ring;
	(*fence)->owner = owner;
	fence_init(&(*fence)->base, &amdgpu_fence_ops,
		&ring->fence_drv.fence_queue.lock,
		adev->fence_context + ring->idx,
		(*fence)->seq);
	amdgpu_ring_emit_fence(ring, ring->fence_drv.gpu_addr,
			       (*fence)->seq,
			       AMDGPU_FENCE_FLAG_INT);
	trace_amdgpu_fence_emit(ring->adev->ddev, ring->idx, (*fence)->seq);
	return 0;
}

/**
 * amdgpu_fence_check_signaled - callback from fence_queue
 *
 * this function is called with fence_queue lock held, which is also used
 * for the fence locking itself, so unlocked variants are used for
 * fence_signal, and remove_wait_queue.
 */
static int amdgpu_fence_check_signaled(wait_queue_t *wait, unsigned mode, int flags, void *key)
{
	struct amdgpu_fence *fence;
	struct amdgpu_device *adev;
	u64 seq;
	int ret;

	fence = container_of(wait, struct amdgpu_fence, fence_wake);
	adev = fence->ring->adev;

	/*
	 * We cannot use amdgpu_fence_process here because we're already
	 * in the waitqueue, in a call from wake_up_all.
	 */
	seq = atomic64_read(&fence->ring->fence_drv.last_seq);
	if (seq >= fence->seq) {
		ret = fence_signal_locked(&fence->base);
		if (!ret)
			FENCE_TRACE(&fence->base, "signaled from irq context\n");
		else
			FENCE_TRACE(&fence->base, "was already signaled\n");

		__remove_wait_queue(&fence->ring->fence_drv.fence_queue, &fence->fence_wake);
		fence_put(&fence