1. 根目录:
2. drivers
3. gpu
4. drm
5. virtio
6. virtgpu_fence.c

/*
 * Copyright (C) 2015 Red Hat, Inc.
 * 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, 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 COPYRIGHT OWNER(S) 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.
 */

#include <drm/drmP.h>
#include "virtgpu_drv.h"

static const char *virtio_get_driver_name(struct fence *f)
{
	return "virtio_gpu";
}

static const char *virtio_get_timeline_name(struct fence *f)
{
	return "controlq";
}

static bool virtio_enable_signaling(struct fence *f)
{
	return true;
}

static bool virtio_signaled(struct fence *f)
{
	struct virtio_gpu_fence *fence = to_virtio_fence(f);

	if (atomic64_read(&fence->drv->last_seq) >= fence->seq)
		return true;
	return false;
}

static void virtio_fence_value_str(struct fence *f, char *str, int size)
{
	struct virtio_gpu_fence *fence = to_virtio_fence(f);

	snprintf(str, size, "%llu", fence->seq);
}

static void virtio_timeline_value_str(struct fence *f, char *str, int size)
{
	struct virtio_gpu_fence *fence = to_virtio_fence(f);

	snprintf(str, size, "%llu", (u64)atomic64_read(&fence->drv->last_seq));
}

static const struct fence_ops virtio_fence_ops = {
	.get_driver_name     = virtio_get_driver_name,
	.get_timeline_name   = virtio_get_timeline_name,
	.enable_signaling    = virtio_enable_signaling,
	.signaled            = virtio_signaled,
	.wait                = fence_default_wait,
	.fence_value_str     = virtio_fence_value_str,
	.timeline_value_str  = virtio_timeline_value_str,
};

int virtio_gpu_fence_emit(struct virtio_gpu_device *vgdev,
			  struct virtio_gpu_ctrl_hdr *cmd_hdr,
			  struct virtio_gpu_fence **fence)
{
	struct virtio_gpu_fence_driver *drv = &vgdev->fence_drv;
	unsigned long irq_flags;

	*fence = kmalloc(sizeof(struct virtio_gpu_fence), GFP_ATOMIC);
	if ((*fence) == NULL)
		return -ENOMEM;

	spin_lock_irqsave(&drv->lock, irq_flags);
	(*fence)->drv = drv;
	(*fence)->seq = ++drv->sync_seq;
	fence_init(&(*fence)->f, &virtio_fence_ops, &drv->lock,
		   0, (*fence)->seq);
	fence_get(&(*fence)->f);
	list_add_tail(&(*fence)->node, &drv->fences);
	spin_unlock_irqrestore(&drv->lock, irq_flags);

	cmd_hdr->flags |= cpu_to_le32(VIRTIO_GPU_FLAG_FENCE);
	cmd_hdr->fence_id = cpu_to_le64((*fence)->seq);
	return 0;
}

void virtio_gpu_fence_event_process(struct virtio_gpu_device *vgdev,
				    u64 last_seq)
{
	struct virtio_gpu_fence_driver *drv = &vgdev->fence_drv;
	struct virtio_gpu_fence *fence, *tmp;
	unsigned long irq_flags;

	spin_lock_irqsave(&drv->lock, irq_flags);
	atomic64_set(&vgdev->fence_drv.last_seq, last_seq);
	list_for_each_entry_safe(fence, tmp, &drv->fences, node) {
		if (last_seq < fence->seq)
			continue;
		fence_signal_locked(&fence->f);
		list_del(&fence->node);
		fence_put(&fence->f);
	}
	spin_unlock_irqrestore(&drv->lock, irq_flags);
}