[libcamera-devel] [RFC PATCH 1/2] android: Introduce PlatformFrameBufferAllocator
Hirokazu Honda
hiroh at chromium.org
Wed Oct 20 06:01:46 CEST 2021
Hi Laurent, thank you for comments.
On Wed, Oct 13, 2021 at 12:18 PM Laurent Pinchart
<laurent.pinchart at ideasonboard.com> wrote:
>
> Hi Hiro,
>
> Thank you for the patch.
>
> On Mon, Sep 27, 2021 at 07:48:20PM +0900, Hirokazu Honda wrote:
> > PlatformFrameBufferAllocator allocates FrameBuffer(s) using
> > cros::CameraBufferManager on ChromeOS and gralloc on non
> > ChromeOS platform. The allocated FrameBuffer(s) are owned by
> > PlatformFrameBufferAllocator an destroyed when
>
> s/an/and/
>
> > PlatformFrameBufferAllocator is destroyed.
>
> It would also be useful to explain in the commit message why this is
> needed.
>
> Overall the patch looks pretty good. I think we're reaching a point
> where we'll have to document Android classes such as this one though,
> but it doesn't have to be part of this series.
>
> > Signed-off-by: Hirokazu Honda <hiroh at chromium.org>
> > ---
> > src/android/frame_buffer.h | 53 +++++++++++
> > src/android/mm/cros_frame_buffer.cpp | 85 +++++++++++++++++
> > src/android/mm/generic_frame_buffer.cpp | 116 ++++++++++++++++++++++++
> > src/android/mm/meson.build | 6 +-
> > 4 files changed, 258 insertions(+), 2 deletions(-)
> > create mode 100644 src/android/frame_buffer.h
> > create mode 100644 src/android/mm/cros_frame_buffer.cpp
> > create mode 100644 src/android/mm/generic_frame_buffer.cpp
> >
> > diff --git a/src/android/frame_buffer.h b/src/android/frame_buffer.h
> > new file mode 100644
> > index 00000000..6aafeaf3
> > --- /dev/null
> > +++ b/src/android/frame_buffer.h
> > @@ -0,0 +1,53 @@
> > +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> > +/*
> > + * Copyright (C) 2021, Google Inc.
> > + *
> > + * frame_buffer.h - Frame buffer allocating interface definition
>
> s/allocating/allocator/
>
> > + */
> > +#ifndef __ANDROID_FRAME_BUFFER_H__
> > +#define __ANDROID_FRAME_BUFFER_H__
> > +
> > +#include <memory>
> > +#include <vector>
> > +
> > +#include <libcamera/base/class.h>
> > +#include <libcamera/camera.h>
> > +#include <libcamera/framebuffer.h>
> > +#include <libcamera/geometry.h>
> > +
> > +class CameraDevice;
> > +
> > +class PlatformFrameBufferAllocator : libcamera::Extensible
> > +{
> > + LIBCAMERA_DECLARE_PRIVATE()
> > +
> > +public:
> > + explicit PlatformFrameBufferAllocator(CameraDevice *const cameraDevice);
> > + ~PlatformFrameBufferAllocator();
> > +
> > + const std::vector<std::unique_ptr<libcamera::FrameBuffer>> &
> > + allocate(int halPixelFormat,
> > + const libcamera::Size &size,
> > + uint32_t usage,
> > + size_t numBuffers);
> > +};
> > +
> > +#define PUBLIC_FRAME_BUFFER_IMPLEMENTATION \
>
> I'm not a big fan of this design pattern, but it already exists in
> camera_buffer.h, so we can keep it for now and address both later.
>
> > +PlatformFrameBufferAllocator::PlatformFrameBufferAllocator( \
> > + CameraDevice *const cameraDevice) \
> > + : Extensible(std::make_unique<Private>(this, cameraDevice)) \
> > +{ \
> > +} \
> > +PlatformFrameBufferAllocator::~PlatformFrameBufferAllocator() \
> > +{ \
> > +} \
> > +const std::vector<std::unique_ptr<libcamera::FrameBuffer>>& \
> > +PlatformFrameBufferAllocator::allocate(int halPixelFormat, \
> > + const libcamera::Size& size, \
> > + uint32_t usage, \
> > + size_t numBuffers) \
> > +{ \
> > + return _d()->allocate(halPixelFormat, size, usage, numBuffers); \
> > +}
> > +
> > +#endif /* __ANDROID_FRAME_BUFFER_H__ */
> > diff --git a/src/android/mm/cros_frame_buffer.cpp b/src/android/mm/cros_frame_buffer.cpp
> > new file mode 100644
> > index 00000000..114c739b
> > --- /dev/null
> > +++ b/src/android/mm/cros_frame_buffer.cpp
> > @@ -0,0 +1,85 @@
> > +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> > +/*
> > + * Copyright (C) 2021, Google Inc.
> > + *
> > + * cros_frame_buffer.cpp - allocate FrameBuffer for Chromium OS buffer backend
>
> s/allocate/Allocate/
>
> > + * using CameraBufferManager
> > + */
> > +
> > +#include "../frame_buffer.h"
> > +
> > +#include <libcamera/base/log.h>
> > +
> > +#include "cros-camera/camera_buffer_manager.h"
> > +
> > +#include "../camera_device.h"
> > +
> > +using namespace libcamera;
> > +
> > +LOG_DECLARE_CATEGORY(HAL)
> > +
> > +class PlatformFrameBufferAllocator::Private : public Extensible::Private
> > +{
> > + LIBCAMERA_DECLARE_PUBLIC(PlatformFrameBufferAllocator)
> > +
> > +public:
> > + Private([[maybe_unused]] PlatformFrameBufferAllocator *allocator,
> > + [[maybe_unused]] CameraDevice *const cameraDevice)
> > + {
> > + }
> > +
> > + ~Private() = default;
> > +
> > + const std::vector<std::unique_ptr<libcamera::FrameBuffer>> &
> > + allocate(int halPixelFormat,
> > + const libcamera::Size &size,
> > + uint32_t usage,
> > + size_t numBuffers);
I think to return std::unique_ptr<libcamera::FrameBuffer> so that we
don't have to consider proper numBuffers.
It is necessary to attach something libcamera::FrameBuffer, for
example, cros::ScopedBufferHandle in cros_frame_buffer.
However, libcamera::FrameBuffer is marked final. How should I solve
this problem?
Is it fine to remove the final mark?
-Hiro
> > +
> > +private:
> > + std::vector<std::unique_ptr<libcamera::FrameBuffer>> allocatedBuffers_;
> > + std::vector<cros::ScopedBufferHandle> allocatedHandles_;
> > +};
> > +
> > +const std::vector<std::unique_ptr<libcamera::FrameBuffer>> &
> > +PlatformFrameBufferAllocator::Private::allocate(
> > + int halPixelFormat, const libcamera::Size &size, uint32_t usage,
> > + size_t numBuffers)
> > +{
> > + ASSERT(allocatedBuffers_.empty());
> > +
> > + std::vector<std::unique_ptr<libcamera::FrameBuffer>> buffers;
> > + for (size_t i = 0; i < numBuffers; ++i) {
> > + cros::ScopedBufferHandle handle =
> > + cros::CameraBufferManager::AllocateScopedBuffer(
> > + size.width, size.height, halPixelFormat, usage);
> > + if (!handle) {
> > + LOG(HAL, Error) << "Failed allocate buffer_handle";
>
> s/Failed/Failed to/
>
> > + return allocatedBuffers_;
>
> I think
>
> return {};
>
> would be more explicit. For a moment I thought the function would return
> a partial vector of some of the allocations succeeded. Same below.
>
> > + }
> > +
> > + const size_t numPlanes = cros::CameraBufferManager::GetNumPlanes(*handle);
> > + std::vector<FrameBuffer::Plane> planes(numPlanes);
> > + for (size_t j = 0; j < numPlanes; ++j) {
>
> This could also be written
>
> for (auto [j, plane] : utils::enumerate(planes)) {
>
> Up to you.
>
> > + FileDescriptor fd{ (*handle)->data[0] };
> > + if (!fd.isValid()) {
> > + LOG(HAL, Fatal) << "Invalid fd";
> > + return allocatedBuffers_;
> > + }
>
> You can move this outside of the loop. FileDescriptor uses implicit
> sharing of the actual fd, so all instances of planes[j].fd will use the
> same numerical fd, avoiding the dup() call and saving file descriptor
> space.
>
> > +
> > + planes[j].fd = fd;
> > + planes[j].offset =
> > + cros::CameraBufferManager::GetPlaneOffset(*handle, j);
> > + planes[j].length =
> > + cros::CameraBufferManager::GetPlaneSize(*handle, j);
> > + }
> > +
> > + buffers.push_back(std::make_unique<FrameBuffer>(planes));
> > + allocatedHandles_.push_back(std::move(handle));
> > + }
> > +
> > + allocatedBuffers_ = std::move(buffers);
> > + return allocatedBuffers_;
> > +}
> > +
> > +PUBLIC_FRAME_BUFFER_IMPLEMENTATION
> > diff --git a/src/android/mm/generic_frame_buffer.cpp b/src/android/mm/generic_frame_buffer.cpp
> > new file mode 100644
> > index 00000000..b387d5a2
> > --- /dev/null
> > +++ b/src/android/mm/generic_frame_buffer.cpp
> > @@ -0,0 +1,116 @@
> > +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> > +/*
> > + * Copyright (C) 2021, Google Inc.
> > + *
> > + * generic_camera_buffer.cpp - allocate FrameBuffer for Generic Android frame
> > + * buffer backend
> > + */
> > +
> > +#include "../frame_buffer.h"
> > +
> > +#include <libcamera/base/log.h>
> > +#include <libcamera/internal/formats.h>
> > +
> > +#include <hardware/camera3.h>
> > +#include <hardware/gralloc.h>
> > +#include <hardware/hardware.h>
> > +
> > +#include "../camera_device.h"
> > +
> > +using namespace libcamera;
> > +
> > +LOG_DECLARE_CATEGORY(HAL)
> > +
> > +class PlatformFrameBufferAllocator::Private : public Extensible::Private
> > +{
> > + LIBCAMERA_DECLARE_PUBLIC(PlatformFrameBufferAllocator)
> > +
> > +public:
> > + Private([[maybe_unused]] PlatformFrameBufferAllocator *allocator,
> > + CameraDevice *const cameraDevice)
> > + : cameraDevice_(cameraDevice),
> > + hardwareModule_(cameraDevice->camera3Device()->common.module)
>
> allocDevice_ should be initialized to nullptr or the destructor could
> end up calling gralloc_close() on a random pointer.
>
> > + {
> > + ASSERT(!!hardwareModule_);
>
> Why not
>
> ASSERT(hardwareModule_);
>
> ?
>
> > + }
> > +
> > + ~Private() override;
> > +
> > + const std::vector<std::unique_ptr<libcamera::FrameBuffer>> &
> > + allocate(int halPixelFormat,
> > + const libcamera::Size &size,
> > + uint32_t usage,
> > + size_t numBuffers);
> > +
> > +private:
> > + const CameraDevice *const cameraDevice_;
> > + struct hw_module_t *const hardwareModule_;
> > + struct alloc_device_t *allocDevice_;
> > +
> > + std::vector<std::unique_ptr<libcamera::FrameBuffer>> allocatedBuffers_;
> > + std::vector<buffer_handle_t> bufferHandles_;
> > +};
> > +
> > +PlatformFrameBufferAllocator::Private::~Private()
> > +{
> > + for (buffer_handle_t &handle : bufferHandles_) {
> > + ASSERT(allocDevice_);
>
> I would drop the assert, this really can't happen.
>
> > + allocDevice_->free(allocDevice_, handle);
> > + }
>
> A blank line would be nice.
>
> > + if (allocDevice_)
> > + gralloc_close(allocDevice_);
> > +}
> > +
> > +const std::vector<std::unique_ptr<libcamera::FrameBuffer>> &
> > +PlatformFrameBufferAllocator::Private::allocate(
> > + int halPixelFormat, const libcamera::Size &size, uint32_t usage,
> > + size_t numBuffers)
> > +{
> > + ASSERT(allocatedBuffers_.empty());
> > + ASSERT(bufferHandles_.empty());
> > + ASSERT(!allocDevice_);
> > +
> > + int ret = gralloc_open(hardwareModule_, &allocDevice_);
> > + if (ret) {
> > + LOG(HAL, Error) << "gralloc_open() failed: " << ret;
> > + return allocatedBuffers_;
>
> Same here,
>
> return {};
>
> > + }
> > +
> > + int stride = 0;
> > + for (size_t i = 0; i < numBuffers; ++i) {
> > + buffer_handle_t handle{};
> > + ret = allocDevice_->alloc(allocDevice_, size.width, size.height,
> > + halPixelFormat, usage, &handle, &stride);
>
> I suppose the stride is guaranteed to be the same for all allocations ?
>
> > + if (ret) {
> > + LOG(HAL, Error) << "failed buffer allocating: " << ret;
> > + return allocatedBuffers_;
> > + }
> > +
> > + bufferHandles_.push_back(handle);
> > + }
> > +
> > + const libcamera::PixelFormat pixelFormat =
> > + cameraDevice_->capabilities()->toPixelFormat(halPixelFormat);
> > + const auto &info = PixelFormatInfo::info(pixelFormat);
> > + const unsigned int numPlanes = info.numPlanes();
> > +
> > + allocatedBuffers_.reserve(numBuffers);
> > + for (const buffer_handle_t &handle : bufferHandles_) {
> > + std::vector<FrameBuffer::Plane> planes(numPlanes);
> > + size_t offset = 0;
> > + for (size_t i = 0; i < numPlanes; ++i) {
>
> Here too you could use utils::enumerate().
>
> > + planes[i].fd = FileDescriptor(handle->data[i]);
> > + size_t planeSize = info.planeSize(size.height, i, stride);
> > +
> > + planes[i].offset = offset;
>
> Does Android use a different dmabuf fd for each plane ? If not, I think
> the offset should be 0, and if it does, we could move the FileDescriptor
> construction outside of the loop.
>
> > + planes[i].length = planeSize;
> > + offset += planeSize;
> > + }
> > +
> > + allocatedBuffers_.push_back(std::make_unique<FrameBuffer>(planes));
> > + }
> > +
> > + return allocatedBuffers_;
> > +}
> > +
> > +PUBLIC_FRAME_BUFFER_IMPLEMENTATION
> > diff --git a/src/android/mm/meson.build b/src/android/mm/meson.build
> > index eeb5cc2e..d1ad64d9 100644
> > --- a/src/android/mm/meson.build
> > +++ b/src/android/mm/meson.build
> > @@ -2,8 +2,10 @@
> >
> > platform = get_option('android_platform')
> > if platform == 'generic'
> > - android_hal_sources += files(['generic_camera_buffer.cpp'])
> > + android_hal_sources += files(['generic_camera_buffer.cpp',
> > + 'generic_frame_buffer.cpp'])
> > elif platform == 'cros'
> > - android_hal_sources += files(['cros_camera_buffer.cpp'])
> > + android_hal_sources += files(['cros_camera_buffer.cpp',
> > + 'cros_frame_buffer.cpp'])
> > android_deps += [dependency('libcros_camera')]
> > endif
>
> --
> Regards,
>
> Laurent Pinchart
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