Quelle  virtgpu_fence.c   Sprache: 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 <trace/events/dma_fence.h>

#include "virtgpu_drv.h"

#define to_virtio_gpu_fence(x) \
 container_of(x, struct virtio_gpu_fence, f)

static const char *virtio_gpu_get_driver_name(struct dma_fence *f)
{
 return "virtio_gpu";
}

static const char *virtio_gpu_get_timeline_name(struct dma_fence *f)
{
 return "controlq";
}

static bool virtio_gpu_fence_signaled(struct dma_fence *f)
{
 /* leaked fence outside driver before completing
  * initialization with virtio_gpu_fence_emit.
 */
 WARN_ON_ONCE(f->seqno == 0);
 return false;
}

static const struct dma_fence_ops virtio_gpu_fence_ops = {
 .get_driver_name     = virtio_gpu_get_driver_name,
 .get_timeline_name   = virtio_gpu_get_timeline_name,
 .signaled            = virtio_gpu_fence_signaled,
};

struct virtio_gpu_fence *virtio_gpu_fence_alloc(struct virtio_gpu_device *vgdev,
      uint64_t base_fence_ctx,
      uint32_t ring_idx)
{
 uint64_t fence_context = base_fence_ctx + ring_idx;
 struct virtio_gpu_fence_driver *drv = &vgdev->fence_drv;
 struct virtio_gpu_fence *fence = kzalloc(sizeof(struct virtio_gpu_fence),
       GFP_KERNEL);

 if (!fence)
  return fence;

 fence->drv = drv;
 fence->ring_idx = ring_idx;
 fence->emit_fence_info = !(base_fence_ctx == drv->context);

 /* This only partially initializes the fence because the seqno is
  * unknown yet.  The fence must not be used outside of the driver
  * until virtio_gpu_fence_emit is called.
 */

 dma_fence_init(&fence->f, &virtio_gpu_fence_ops, &drv->lock,
         fence_context, 0);

 return fence;
}

void 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;

 spin_lock_irqsave(&drv->lock, irq_flags);
 fence->fence_id = fence->f.seqno = ++drv->current_fence_id;
 dma_fence_get(&fence->f);
 list_add_tail(&fence->node, &drv->fences);
 spin_unlock_irqrestore(&drv->lock, irq_flags);

 trace_dma_fence_emit(&fence->f);

 cmd_hdr->flags |= cpu_to_le32(VIRTIO_GPU_FLAG_FENCE);
 cmd_hdr->fence_id = cpu_to_le64(fence->fence_id);

 /* Only currently defined fence param. */
 if (fence->emit_fence_info) {
  cmd_hdr->flags |=
   cpu_to_le32(VIRTIO_GPU_FLAG_INFO_RING_IDX);
  cmd_hdr->ring_idx = (u8)fence->ring_idx;
 }
}

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

 spin_lock_irqsave(&drv->lock, irq_flags);
 atomic64_set(&vgdev->fence_drv.last_fence_id, fence_id);
 list_for_each_entry_safe(curr, tmp, &drv->fences, node) {
  if (fence_id != curr->fence_id)
   continue;

  signaled = curr;

  /*
   * Signal any fences with a strictly smaller sequence number
   * than the current signaled fence.
 */
  list_for_each_entry_safe(curr, tmp, &drv->fences, node) {
   /* dma-fence contexts must match */
   if (signaled->f.context != curr->f.context)
    continue;

   if (!dma_fence_is_later(&signaled->f, &curr->f))
    continue;

   dma_fence_signal_locked(&curr->f);
   if (curr->e) {
    drm_send_event(vgdev->ddev, &curr->e->base);
    curr->e = NULL;
   }

   list_del(&curr->node);
   dma_fence_put(&curr->f);
  }

  dma_fence_signal_locked(&signaled->f);
  if (signaled->e) {
   drm_send_event(vgdev->ddev, &signaled->e->base);
   signaled->e = NULL;
  }

  list_del(&signaled->node);
  dma_fence_put(&signaled->f);
  break;
 }
 spin_unlock_irqrestore(&drv->lock, irq_flags);
}