ozone: Implement zero/one-copy texture for Ozone GBM.

ui/ozone/platform/drm/gpu/client_native_pixmap_vgem.cc

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ui/ozone/platform/drm/gpu/client_native_pixmap_vgem.h"
+
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <vgem_drm.h>
+#include <xf86drm.h>
+
+#include "base/trace_event/trace_event.h"
+
+namespace ui {
+
+// static
+scoped_ptr<ClientNativePixmap> ClientNativePixmapVgem::Create(
+    const gfx::NativePixmapHandle& handle,
+    const base::FileDescriptor& vgem_handle,
+    const gfx::Size& size) {
+  DCHECK_GE(vgem_handle.fd, 0);
+  DCHECK_GE(handle.fd.fd, 0);
+  uint32_t vgem_bo_handle = 0;
+  int ret = drmPrimeFDToHandle(vgem_handle.fd, handle.fd.fd, &vgem_bo_handle);
+  if (ret) {
+    PLOG(ERROR) << "drmPrimeFDToHandle failed, handle:" << vgem_bo_handle;
+    return nullptr;
+  }
+  return make_scoped_ptr(new ClientNativePixmapVgem(vgem_handle, vgem_bo_handle,
+                                                    size, handle.stride));
+}
+
+ClientNativePixmapVgem::ClientNativePixmapVgem(
+    const base::FileDescriptor& vgem_handle,
+    uint32_t vgem_bo_handle,
+    const gfx::Size& size,
+    int stride)
+    : vgem_fd_(vgem_handle),
+      vgem_bo_handle_(vgem_bo_handle),
+      size_(size),
+      stride_(stride),
+      data_(nullptr) {
+  DCHECK(vgem_bo_handle_);
+}
+
+ClientNativePixmapVgem::~ClientNativePixmapVgem() {
+  DCHECK(!data_);
+  struct drm_gem_close close = {0};
+  close.handle = vgem_bo_handle_;
+  int ret = drmIoctl(vgem_fd_.fd, DRM_IOCTL_GEM_CLOSE, &close);
+  if (ret)
+    PLOG(ERROR) << "fail to free a vgem buffer. error:" << ret;

[spang, 2015/08/12 21:40:03]

PLOG() handles the error message for you, please don't print out the return
value. It will always be -1.

[dshwang, 2015/08/13 11:30:55]

Done. Change it to DCHECK

+}
+
+bool ClientNativePixmapVgem::Map(void** data) {
+  TRACE_EVENT0("gpu", "ClientNativePixmapVgem::Map");
+  DCHECK(!data_);
+  struct drm_mode_map_dumb mmap_arg = {0};
+  mmap_arg.handle = vgem_bo_handle_;
+
+  int ret = drmIoctl(vgem_fd_.fd, DRM_IOCTL_VGEM_MODE_MAP_DUMB, &mmap_arg);
+  if (ret) {
+    PLOG(ERROR) << "fail to map a vgem buffer. error:" << ret;

[spang, 2015/08/12 21:40:03]

and here

[dshwang, 2015/08/13 11:30:55]

Done.

+    return false;
+  }
+  DCHECK(mmap_arg.offset);
+
+  size_t size = stride_ * size_.height();
+  data_ = mmap(nullptr, size, (PROT_READ | PROT_WRITE), MAP_SHARED, vgem_fd_.fd,
+               mmap_arg.offset);
+  DCHECK_NE(data_, MAP_FAILED);
+  *data = data_;
+  return true;
+}
+
+void ClientNativePixmapVgem::Unmap() {
+  TRACE_EVENT0("gpu", "ClientNativePixmapVgem::Unmap");
+  DCHECK(data_);
+
+  // TODO(dshwang): keep it consistently mapped, and unmap it in dtor.
+  size_t size = stride_ * size_.height();
+  int ret = munmap(data_, size);
+  if (ret)
+    PLOG(ERROR) << "fail to munmap a vgem buffer. error:" << ret;

[spang, 2015/08/12 21:40:03]

and here

[dshwang, 2015/08/13 11:30:55]

Done.

+  data_ = nullptr;
+}
+
+void ClientNativePixmapVgem::GetStride(int* stride) const {
+  *stride = stride_;
+}
+
+}  // namespace ui