Ozone SkBitmap implementation using DRM buffers

ui/gfx/ozone/impl/drm_skbitmap_ozone.cc

+// Copyright (c) 2013 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/gfx/ozone/impl/drm_skbitmap_ozone.h"
+
+#include <errno.h>
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <xf86drm.h>
+
+#include "base/compiler_specific.h"
+#include "base/logging.h"
+#include "third_party/skia/include/core/SkPixelRef.h"
+
+namespace gfx {
+
+namespace {
+
+void DestroyDumbBuffer(int fd, uint32_t handle) {
+  struct drm_mode_destroy_dumb destroy_request;
+  destroy_request.handle = handle;
+  drmIoctl(fd, DRM_IOCTL_MODE_DESTROY_DUMB, &destroy_request);
+}
+
+// Special DRM implementation of a SkPixelRef. The DRM allocator will create a
+// SkPixelRef for the backing pixels. It will then associate the SkPixelRef with
+// the SkBitmap. SkBitmap will access the allocated memory by locking the pixels
+// in the SkPixelRef.
+// At the end of its life the SkPixelRef is responsible for deallocating the
+// pixel memory.
+class DrmSkPixelRef : public SkPixelRef {
+ public:
+  DrmSkPixelRef(void* pixels,
+                SkColorTable* color_table_,
+                size_t size,
+                int fd,
+                uint32_t handle);
+  virtual ~DrmSkPixelRef();
+
+  virtual void* onLockPixels(SkColorTable** ct) OVERRIDE;
+  virtual void onUnlockPixels() OVERRIDE;
+
+  SK_DECLARE_UNFLATTENABLE_OBJECT()
+ private:
+  // Raw pointer to the pixel memory.
+  void* pixels_;
+
+  // Optional color table associated with the pixel memory.
+  SkColorTable* color_table_;
+
+  // Size of the allocated memory.
+  size_t size_;
+
+  // File descriptor to the graphics card used to allocate/deallocate the
+  // memory.
+  int fd_;
+
+  // Handle for the allocated memory.
+  uint32_t handle_;
+
+  DISALLOW_COPY_AND_ASSIGN(DrmSkPixelRef);
+};
+
+////////////////////////////////////////////////////////////////////////////////
+// DrmSkPixelRef implementation
+
+DrmSkPixelRef::DrmSkPixelRef(
+    void* pixels,
+    SkColorTable* color_table,
+    size_t size,
+    int fd,
+    uint32_t handle)
+  : pixels_(pixels),
+    color_table_(color_table),
+    size_(size),
+    fd_(fd),
+    handle_(handle) {
+}
+
+DrmSkPixelRef::~DrmSkPixelRef() {
+  munmap(pixels_, size_);
+  DestroyDumbBuffer(fd_, handle_);
+}
+
+void* DrmSkPixelRef::onLockPixels(SkColorTable** ct) {
+  *ct = color_table_;
+  return pixels_;
+}
+
+void DrmSkPixelRef::onUnlockPixels() {
+}
+
+}  // namespace
+
+// Allocates pixel memory for a SkBitmap using DRM dumb buffers.
+class DrmAllocator : public SkBitmap::Allocator {
+ public:
+  DrmAllocator();
+
+  virtual bool allocPixelRef(SkBitmap* bitmap,
+                             SkColorTable* color_table) OVERRIDE;
+
+ private:
+  bool AllocatePixels(DrmSkBitmapOzone* bitmap, SkColorTable* color_table);
+
+  DISALLOW_COPY_AND_ASSIGN(DrmAllocator);
+};
+
+////////////////////////////////////////////////////////////////////////////////
+// DrmAllocator implementation
+
+DrmAllocator::DrmAllocator() {
+}
+
+bool DrmAllocator::allocPixelRef(SkBitmap* bitmap,
+                                 SkColorTable* color_table) {
+  return AllocatePixels(static_cast<DrmSkBitmapOzone*>(bitmap), color_table);
+}
+
+bool DrmAllocator::AllocatePixels(DrmSkBitmapOzone* bitmap,
+                                  SkColorTable* color_table) {
+  struct drm_mode_create_dumb request;
+  request.width = bitmap->width();
+  request.height = bitmap->height();
+  request.bpp = bitmap->bytesPerPixel() << 3;
+  request.flags = 0;
+
+  if (drmIoctl(bitmap->get_fd(), DRM_IOCTL_MODE_CREATE_DUMB, &request) < 0) {
+    DLOG(ERROR) << "Cannot create dumb buffer (" << errno << ") "
+                << strerror(errno);
+    return false;
+  }
+
+  CHECK(request.size == bitmap->getSize());
+
+  bitmap->set_handle(request.handle);
+
+  struct drm_mode_map_dumb map_request;
+  map_request.handle = bitmap->get_handle();
+  if (drmIoctl(bitmap->get_fd(), DRM_IOCTL_MODE_MAP_DUMB, &map_request)) {
+    DLOG(ERROR) << "Cannot prepare dumb buffer for mapping (" << errno << ") "
+                << strerror(errno);
+    DestroyDumbBuffer(bitmap->get_fd(), bitmap->get_handle());
+    return false;
+  }
+
+  void* pixels = mmap(0,
+                      bitmap->getSize(),
+                      PROT_READ | PROT_WRITE,
+                      MAP_SHARED,
+                      bitmap->get_fd(),
+                      map_request.offset);
+  if (pixels == MAP_FAILED) {
+    DLOG(ERROR) << "Cannot mmap dumb buffer (" << errno << ") "
+                << strerror(errno);
+    DestroyDumbBuffer(bitmap->get_fd(), bitmap->get_handle());
+    return false;
+  }
+
+  bitmap->setPixelRef(new DrmSkPixelRef(
+      pixels,
+      color_table,
+      bitmap->getSize(),
+      bitmap->get_fd(),
+      bitmap->get_handle()))->unref();
+  bitmap->lockPixels();
+
+  return true;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// DrmSkBitmapOzone implementation
+
+DrmSkBitmapOzone::DrmSkBitmapOzone(int fd)
+  : fd_(fd),
+    handle_(0),
+    framebuffer_(0) {
+}
+
+DrmSkBitmapOzone::~DrmSkBitmapOzone() {
+}
+
+bool DrmSkBitmapOzone::Initialize() {
+  DrmAllocator drm_allocator;
+  return allocPixels(&drm_allocator, NULL);
+}
+
+uint8_t DrmSkBitmapOzone::GetColorDepth() const {
+  switch (config()) {
+    case SkBitmap::kNo_Config:
+    case SkBitmap::kA1_Config:
+    case SkBitmap::kA8_Config:
+      return 0;
+    case SkBitmap::kIndex8_Config:
+      return 8;
+    case SkBitmap::kRGB_565_Config:
+      return 16;
+    case SkBitmap::kARGB_4444_Config:
+      return 12;
+    case SkBitmap::kARGB_8888_Config:
+      return 24;
+    default:
+      NOTREACHED();
+      return 0;
+  }
+}
+
+}  // namespace gfx