text: /**********************************************************
   * Copyright 2009-2015 VMware, 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 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 AUTHORS OR COPYRIGHT HOLDERS
   * 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 <libsync.h>
  
  #include "util/u_memory.h"
  #include "util/u_atomic.h"
  #include "util/list.h"
  #include "os/os_thread.h"
  
  #include "pipebuffer/pb_buffer_fenced.h"
  
  #include "vmw_screen.h"
  #include "vmw_fence.h"
  
  struct vmw_fence_ops
  {
     /*
      * Immutable members.
      */
     struct pb_fence_ops base;
     struct vmw_winsys_screen *vws;
  
     mtx_t mutex;
  
     /*
      * Protected by mutex;
      */
     struct list_head not_signaled;
     uint32_t last_signaled;
     uint32_t last_emitted;
  };
  
  struct vmw_fence
  {
     struct list_head ops_list;
     int32_t refcount;
     uint32_t handle;
     uint32_t mask;
     int32_t signalled;
     uint32_t seqno;
     int32_t fence_fd;
     boolean imported; /* TRUE if imported from another process */
  };
  
  /**
   * vmw_fence_seq_is_signaled - Check whether a fence seqno is
   * signaled.
   *
   * @ops: Pointer to a struct pb_fence_ops.
   *
   */
  static inline boolean
  vmw_fence_seq_is_signaled(uint32_t seq, uint32_t last, uint32_t cur)
  {
     return (cur - last <= cur - seq);
  }
  
  
  /**
   * vmw_fence_ops - Return the vmw_fence_ops structure backing a
   * struct pb_fence_ops pointer.
   *
   * @ops: Pointer to a struct pb_fence_ops.
   *
   */
  static inline struct vmw_fence_ops *
  vmw_fence_ops(struct pb_fence_ops *ops)
  {
     assert(ops);
     return (struct vmw_fence_ops *)ops;
  }
  
  
  /**
   * vmw_fences_release - Release all fences from the not_signaled
   * list.
   *
   * @ops: Pointer to a struct vmw_fence_ops.
   *
   */
  static void
  vmw_fences_release(struct vmw_fence_ops *ops)
  {
     struct vmw_fence *fence, *n;
  
     mtx_lock(&ops->mutex);
     LIST_FOR_EACH_ENTRY_SAFE(fence, n, &ops->not_signaled, ops_list)
        LIST_DELINIT(&fence->ops_list);
     mtx_unlock(&ops->mutex);
  }
  
  /**
   * vmw_fences_signal - Traverse the not_signaled list and try to
   * signal unsignaled fences.
   *
   * @ops: Pointer to a struct pb_fence_ops.
   * @signaled: Seqno that has signaled.
   * @emitted: Last seqno emitted by the kernel.
   * @has_emitted: Whether we provide the emitted value.
   *
   */
  void
  vmw_fences_signal(struct pb_fence_ops *fence_ops,
                    uint32_t signaled,
                    uint32_t emitted,
                    boolean has_emitted)
  {
     struct vmw_fence_ops *ops = NULL;
     struct vmw_fence *fence, *n;
  
     if (fence_ops == NULL)
        return;
  
     ops = vmw_fence_ops(fence_ops);
     mtx_lock(&ops->mutex);
  
     if (!has_emitted) {
        emitted = ops->last_emitted;
        if (emitted - signaled > (1 << 30))
  	emitted = signaled;
     }
  
     if (signaled == ops->last_signaled && emitted == ops->last_emitted)
        goto out_unlock;
  
     LIST_FOR_EACH_ENTRY_SAFE(fence, n, &ops->not_signaled, ops_list) {
        if (!vmw_fence_seq_is_signaled(fence->seqno, signaled, emitted))
           break;
  
        p_atomic_set(&fence->signalled, 1);
        LIST_DELINIT(&fence->ops_list);
     }
     ops->last_signaled = signaled;
     ops->last_emitted = emitted;
  
  out_unlock:
     mtx_unlock(&ops->mutex);
  }
  
  
  /**
   * vmw_fence - return the vmw_fence object identified by a
   * struct pipe_fence_handle *
   *
   * @fence: The opaque pipe fence handle.
   */
  static inline struct vmw_fence *
  vmw_fence(struct pipe_fence_handle *fence)
  {
     return (struct vmw_fence *) fence;
  }
  
  
  /**
   * vmw_fence_create - Create a user-space fence object.
   *
   * @fence_ops: The fence_ops manager to register with.
   * @handle: Handle identifying the kernel fence object.
   * @mask: Mask of flags that this fence object may signal.
   * @fd: File descriptor to associate with the fence
   *
   * Returns NULL on failure.
   */
  struct pipe_fence_handle *
  vmw_fence_create(struct pb_fence_ops *fence_ops, uint32_t handle,
                   uint32_t seqno, uint32_t mask, int32_t fd)
  {
     struct vmw_fence *fence = CALLOC_STRUCT(vmw_fence);
     struct vmw_fence_ops *ops = NULL;
  
     if (!fence)
        return NULL;
  
     p_atomic_set(&fence->refcount, 1);
     fence->handle = handle;
     fence->mask = mask;
     fence->seqno = seqno;
     fence->fence_fd = fd;
     p_atomic_set(&fence->signalled, 0);
  
     /*
      * If the fence was not created by our device, then we won't
      * manage it with our ops
      */
     if (!fence_ops) {
        fence->imported = true;
        return (struct pipe_fence_handle *) fence;
     }
  
     ops = vmw_fence_ops(fence_ops);
  
     mtx_lock(&ops->mutex);
  
     if (vmw_fence_seq_is_signaled(seqno, ops->last_signaled, seqno)) {
        p_atomic_set(&fence->signalled, 1);
        LIST_INITHEAD(&fence->ops_list);
     } else {
        p_atomic_set(&fence->signalled, 0);
        LIST_ADDTAIL(&fence->ops_list, &ops->not_signaled);
     }
  
     mtx_unlock(&ops->mutex);
  
     return (struct pipe_fence_handle *) fence;
  }
  
  
  /**
   * vmw_fence_destroy - Frees a vmw fence object.
   *
   * Also closes the file handle associated with the object, if any
   */
  static
  void vmw_fence_destroy(struct vmw_fence *vfence)
  {
     if (vfence->fence_fd != -1)
        close(vfence->fence_fd);
  
     FREE(vfence);
  }
  
  
  /**
   * vmw_fence_reference - Reference / unreference a vmw fence object.
   *
   * @vws: Pointer to the winsys screen.
   * @ptr: Pointer to reference transfer destination.
   * @fence: Pointer to object to reference. May be NULL.
   */
  void
  vmw_fence_reference(struct vmw_winsys_screen *vws,
  		    struct pipe_fence_handle **ptr,
  		    struct pipe_fence_handle *fence)
  {
     if (*ptr) {
        struct vmw_fence *vfence = vmw_fence(*ptr);
  
        if (p_atomic_dec_zero(&vfence->refcount)) {
           struct vmw_fence_ops *ops = vmw_fence_ops(vws->fence_ops);
  
           if (!vfence->imported) {
              vmw_ioctl_fence_unref(vws, vfence->handle);
  
              mtx_lock(&ops->mutex);
              LIST_DELINIT(&vfence->ops_list);
              mtx_unlock(&ops->mutex);
           }
  
           vmw_fence_destroy(vfence);
        }
     }
  
     if (fence) {
        struct vmw_fence *vfence = vmw_fence(fence);
  
        p_atomic_inc(&vfence->refcount);
     }
  
     *ptr = fence;
  }
  
  
  /**
   * vmw_fence_signalled - Check whether a fence object is signalled.
   *
   * @vws: Pointer to the winsys screen.
   * @fence: Handle to the fence object.
   * @flag: Fence flags to check. If the fence object can't signal
   * a flag, it is assumed to be already signaled.
   *
   * Returns 0 if the fence object was signaled, nonzero otherwise.
   */
  int
  vmw_fence_signalled(struct vmw_winsys_screen *vws,
  		   struct pipe_fence_handle *fence,
  		   unsigned flag)
  {
     struct vmw_fence *vfence;
     int32_t vflags = SVGA_FENCE_FLAG_EXEC;
     int ret;
     uint32_t old;
  
     if (!fence)
        return 0;
  
     vfence = vmw_fence(fence);
     old = p_atomic_read(&vfence->signalled);
  
     vflags &= ~vfence->mask;
  
     if ((old & vflags) == vflags)
        return 0;
  
     /*
      * Currently we update signaled fences on each execbuf call.
      * That should really be sufficient, and we can avoid
      * a lot of kernel calls this way.
      */
  #if 1
     ret = vmw_ioctl_fence_signalled(vws, vfence->handle, vflags);
  
     if (ret == 0)
        p_atomic_set(&vfence->signalled, 1);
     return ret;
  #else
     (void) ret;
     return -1;
  #endif
  }
  
  /**
   * vmw_fence_finish - Wait for a fence object to signal.
   *
   * @vws: Pointer to the winsys screen.
   * @fence: Handle to the fence object.
   * @timeout: How long to wait before timing out.
   * @flag: Fence flags to wait for. If the fence object can't signal
   * a flag, it is assumed to be already signaled.
   *
   * Returns 0 if the wait succeeded. Nonzero otherwise.
   */
  int
  vmw_fence_finish(struct vmw_winsys_screen *vws,
  		 struct pipe_fence_handle *fence,
  		 uint64_t timeout,
  		 unsigned flag)
  {
     struct vmw_fence *vfence;
     int32_t vflags = SVGA_FENCE_FLAG_EXEC;
     int ret;
     uint32_t old;
  
     if (!fence)
        return 0;
  
     vfence = vmw_fence(fence);
  
     if (vfence->imported) {
        ret = sync_wait(vfence->fence_fd, timeout / 1000000);
  
        if (!ret)
           p_atomic_set(&vfence->signalled, 1);
  
        return !!ret;
     }
  
     old = p_atomic_read(&vfence->signalled);
     vflags &= ~vfence->mask;
  
     if ((old & vflags) == vflags)
        return 0;
  
     ret = vmw_ioctl_fence_finish(vws, vfence->handle, vflags);
  
     if (ret == 0) {
        int32_t prev = old;
  
        do {
  	 old = prev;
  	 prev = p_atomic_cmpxchg(&vfence->signalled, old, old | vflags);
        } while (prev != old);
     }
  
     return ret;
  }
  
  /**
   * vmw_fence_get_fd
   *
   * Returns the file descriptor associated with the fence
   */
  int
  vmw_fence_get_fd(struct pipe_fence_handle *fence)
  {
     struct vmw_fence *vfence;
  
     if (!fence)
        return -1;
  
     vfence = vmw_fence(fence);
     return vfence->fence_fd;
  }
  
  
  /**
   * vmw_fence_ops_fence_reference - wrapper for the pb_fence_ops api.
   *
   * wrapper around vmw_fence_reference.
   */
  static void
  vmw_fence_ops_fence_reference(struct pb_fence_ops *ops,
                                struct pipe_fence_handle **ptr,
                                struct pipe_fence_handle *fence)
  {
     struct vmw_winsys_screen *vws = vmw_fence_ops(ops)->vws;
  
     vmw_fence_reference(vws, ptr, fence);
  }
  
  /**
   * vmw_fence_ops_fence_signalled - wrapper for the pb_fence_ops api.
   *
   * wrapper around vmw_fence_signalled.
   */
  static int
  vmw_fence_ops_fence_signalled(struct pb_fence_ops *ops,
                                struct pipe_fence_handle *fence,
                                unsigned flag)
  {
     struct vmw_winsys_screen *vws = vmw_fence_ops(ops)->vws;
  
     return vmw_fence_signalled(vws, fence, flag);
  }
  
  
  /**
   * vmw_fence_ops_fence_finish - wrapper for the pb_fence_ops api.
   *
   * wrapper around vmw_fence_finish.
   */
  static int
  vmw_fence_ops_fence_finish(struct pb_fence_ops *ops,
                             struct pipe_fence_handle *fence,
                             unsigned flag)
  {
     struct vmw_winsys_screen *vws = vmw_fence_ops(ops)->vws;
  
     return vmw_fence_finish(vws, fence, PIPE_TIMEOUT_INFINITE, flag);
  }
  
  
  /**
   * vmw_fence_ops_destroy - Destroy a pb_fence_ops function table.
   *
   * @ops: The function table to destroy.
   *
   * Part of the pb_fence_ops api.
   */
  static void
  vmw_fence_ops_destroy(struct pb_fence_ops *ops)
  {
     vmw_fences_release(vmw_fence_ops(ops));
     FREE(ops);
  }
  
  
  /**
   * vmw_fence_ops_create - Create a pb_fence_ops function table.
   *
   * @vws: Pointer to a struct vmw_winsys_screen.
   *
   * Returns a pointer to a pb_fence_ops function table to interface
   * with pipe_buffer. This function is typically called on driver setup.
   *
   * Returns NULL on failure.
   */
  struct pb_fence_ops *
  vmw_fence_ops_create(struct vmw_winsys_screen *vws) 
  {
     struct vmw_fence_ops *ops;
  
     ops = CALLOC_STRUCT(vmw_fence_ops);
     if(!ops)
        return NULL;
  
     (void) mtx_init(&ops->mutex, mtx_plain);
     LIST_INITHEAD(&ops->not_signaled);
     ops->base.destroy = &vmw_fence_ops_destroy;
     ops->base.fence_reference = &vmw_fence_ops_fence_reference;
     ops->base.fence_signalled = &vmw_fence_ops_fence_signalled;
     ops->base.fence_finish = &vmw_fence_ops_fence_finish;
  
     ops->vws = vws;
  
     return &ops->base;
  }
  