[libcamera-devel] [PATCH v2 4/4] android: mm: generic: Use GraphicBufferAllocator instead of gralloc.h

[Jacopo Mondi]

HI Mattijs

 nice work!

On Tue, Sep 12, 2023 at 04:15:23PM +0200, Mattijs Korpershoek via libcamera-devel wrote:
> gralloc.h is a very old API that has been deprecated at least since
> Android P (9).
>
> Switch over to a higher level abstraction of gralloc from libui, which
> is compatible with Android 11 and up.
> Libui:
> * is provided in the VNDK (so it's available to vendors).
> * is also used in the camera vts test named VtsAidlHalCameraProvider_TargetTest.
>
> Drop the libhardware stub since we no longer need it.
>
> Notes:
> * GraphicsBufferAllocator being a Singleton, buffer lifecycle
>   management is easier.
> * The imported headers from Android generate the -Wextra-semi warning.
>   To avoid patching the files, a pragma has been added before inclusion.
>
> Signed-off-by: Mattijs Korpershoek <mkorpershoek at baylibre.com>
> ---
>  src/android/mm/generic_frame_buffer_allocator.cpp | 61 ++++++++---------------
>  src/android/mm/libhardware_stub.c                 | 17 -------
>  src/android/mm/meson.build                        |  8 ++-
>  3 files changed, 23 insertions(+), 63 deletions(-)
>
> diff --git a/src/android/mm/generic_frame_buffer_allocator.cpp b/src/android/mm/generic_frame_buffer_allocator.cpp
> index 7ecef2c669df..468579068c32 100644
> --- a/src/android/mm/generic_frame_buffer_allocator.cpp
> +++ b/src/android/mm/generic_frame_buffer_allocator.cpp
> @@ -16,8 +16,11 @@
>  #include "libcamera/internal/framebuffer.h"
>
>  #include <hardware/camera3.h>
> -#include <hardware/gralloc.h>

our version of include/android/system/core/include/system/camera.h
still includes gralloc.h. We should update all headers most probably

> -#include <hardware/hardware.h>
> +#pragma GCC diagnostic push
> +#pragma GCC diagnostic ignored "-Wextra-semi"
> +#include <ui/GraphicBufferAllocator.h>
> +#pragma GCC diagnostic pop
> +#include <utils/Errors.h>
>
>  #include "../camera_device.h"
>  #include "../frame_buffer_allocator.h"
> @@ -33,35 +36,28 @@ class GenericFrameBufferData : public FrameBuffer::Private
>  	LIBCAMERA_DECLARE_PUBLIC(FrameBuffer)
>
>  public:
> -	GenericFrameBufferData(struct alloc_device_t *allocDevice,
> +	GenericFrameBufferData(android::GraphicBufferAllocator &allocDevice,

You could

        GenericFrameBufferData(buffer_handle_t handle,
                               const std::vector<FrameBuffer::Plane> &planes)
                : FrameBuffer::Private(planes),
                  allocDevice_(android::GraphicBufferAllocator::get()),
                  handle_(handle)

Instead of passing it to the constructor of ::Private.
It does't make much different though, up to you!

>  			       buffer_handle_t handle,
>  			       const std::vector<FrameBuffer::Plane> &planes)
>  		: FrameBuffer::Private(planes), allocDevice_(allocDevice),
>  		  handle_(handle)
>  	{
> -		ASSERT(allocDevice_);
>  		ASSERT(handle_);
>  	}
>
>  	~GenericFrameBufferData() override
>  	{
>  		/*
> -		 * allocDevice_ is used to destroy handle_. allocDevice_ is
> -		 * owned by PlatformFrameBufferAllocator::Private.
> -		 * GenericFrameBufferData must be destroyed before it is
> -		 * destroyed.
> -		 *
> -		 * \todo Consider managing alloc_device_t with std::shared_ptr
> -		 * if this is difficult to maintain.
> -		 *

nice!

>  		 * \todo Thread safety against alloc_device_t is not documented.
>  		 * Is it no problem to call alloc/free in parallel?
>  		 */
> -		allocDevice_->free(allocDevice_, handle_);
> +		android::status_t status = allocDevice_.free(handle_);

Or you could even get the singleton instance here!

> +		if (status != android::NO_ERROR)
> +			LOG(HAL, Error) << "Error freeing framebuffer: " << status;
>  	}
>
>  private:
> -	struct alloc_device_t *allocDevice_;
> +	android::GraphicBufferAllocator &allocDevice_;

Usually reference class members are worrying to me, but this really
just points to a system-wide component accessed via a singleton if i'm
not mistaken, so this should be fine!


>  	const buffer_handle_t handle_;
>  };
>  } /* namespace */
> @@ -73,50 +69,33 @@ class PlatformFrameBufferAllocator::Private : public Extensible::Private
>  public:
>  	Private(CameraDevice *const cameraDevice)
>  		: cameraDevice_(cameraDevice),
> -		  hardwareModule_(nullptr),
> -		  allocDevice_(nullptr)
> +		  allocDevice_(android::GraphicBufferAllocator::get())
>  	{
> -		hw_get_module(GRALLOC_HARDWARE_MODULE_ID, &hardwareModule_);
> -		ASSERT(hardwareModule_);
>  	}
>
> -	~Private() override;
> +	~Private() = default;
>
>  	std::unique_ptr<HALFrameBuffer>
>  	allocate(int halPixelFormat, const libcamera::Size &size, uint32_t usage);
>
>  private:
>  	const CameraDevice *const cameraDevice_;
> -	const struct hw_module_t *hardwareModule_;
> -	struct alloc_device_t *allocDevice_;
> +	android::GraphicBufferAllocator &allocDevice_;
>  };
>
> -PlatformFrameBufferAllocator::Private::~Private()
> -{
> -	if (allocDevice_)
> -		gralloc_close(allocDevice_);
> -	dlclose(hardwareModule_->dso);
> -}
> -
>  std::unique_ptr<HALFrameBuffer>
>  PlatformFrameBufferAllocator::Private::allocate(int halPixelFormat,
>  						const libcamera::Size &size,
>  						uint32_t usage)
>  {
> -	if (!allocDevice_) {
> -		int ret = gralloc_open(hardwareModule_, &allocDevice_);
> -		if (ret) {
> -			LOG(HAL, Fatal) << "gralloc_open() failed: " << ret;
> -			return nullptr;
> -		}
> -	}
> -
> -	int stride = 0;
> +	uint32_t stride = 0;
>  	buffer_handle_t handle = nullptr;
> -	int ret = allocDevice_->alloc(allocDevice_, size.width, size.height,
> -				      halPixelFormat, usage, &handle, &stride);
> -	if (ret) {
> -		LOG(HAL, Error) << "failed buffer allocation: " << ret;
> +
> +	android::status_t status = allocDevice_.allocate(size.width, size.height, halPixelFormat,
> +							 1 /*layerCount*/, usage, &handle, &stride,
> +							 "libcameraHAL");
> +	if (status != android::NO_ERROR) {
> +		LOG(HAL, Error) << "failed buffer allocation: " << status;
>  		return nullptr;
>  	}
>  	if (!handle) {
> diff --git a/src/android/mm/libhardware_stub.c b/src/android/mm/libhardware_stub.c
> deleted file mode 100644
> index 00f15cd90cac..000000000000
> --- a/src/android/mm/libhardware_stub.c
> +++ /dev/null
> @@ -1,17 +0,0 @@
> -/* SPDX-License-Identifier: Apache-2.0 */
> -/*
> - * Copyright (C) 2023, Ideas on Board
> - *
> - * libhardware_stub.c - Android libhardware stub for test compilation
> - */
> -
> -#include <errno.h>
> -
> -#include <hardware/hardware.h>
> -
> -int hw_get_module(const char *id __attribute__((__unused__)),
> -		  const struct hw_module_t **module)
> -{
> -	*module = NULL;
> -	return -ENOTSUP;
> -}
> diff --git a/src/android/mm/meson.build b/src/android/mm/meson.build
> index e9ceb3afba67..203b8c3e5804 100644
> --- a/src/android/mm/meson.build
> +++ b/src/android/mm/meson.build
> @@ -4,13 +4,11 @@ platform = get_option('android_platform')
>  if platform == 'generic'
>      android_hal_sources += files(['generic_camera_buffer.cpp',
>                                    'generic_frame_buffer_allocator.cpp'])
> -    android_deps += [libdl]

libdl was used for ?

>
> -    libhardware = dependency('libhardware', required : false)
> -    if libhardware.found()
> -        android_deps += [libhardware]
> +    libui = dependency('libui', required : false)
> +    if libui.found()
> +        android_deps += [libui]
>      else
> -        android_hal_sources += files(['libhardware_stub.c'])
>          android_hal_sources += files(['graphic_buffer_allocator_stub.cpp'])
>      endif
>  elif platform == 'cros'

All nits
Reviewed-by: Jacopo Mondi <jacopo.mondi at ideasonboard.com>

Thanks
  j

>
> --
> 2.41.0
>