[libcamera-devel] [PATCH v3 2/2] android: Introduce PlatformFrameBufferAllocator

Hirokazu Honda hiroh at chromium.org
Fri Nov 26 04:36:31 CET 2021


Hi Jacopo, thank you for reviewing.

On Thu, Nov 25, 2021 at 9:09 AM Jacopo Mondi <jacopo at jmondi.org> wrote:
>
> Hi Hiro,
>
> On Wed, Nov 24, 2021 at 03:39:47AM +0900, Hirokazu Honda wrote:
> > The existing FrameBufferAllocator is not allowed to allocate a
> > new buffer while Camera is running. This introduces
> > PlatformFrameBufferAllocator. It allocates FrameBuffer using
> > cros::CameraBufferManager on ChromeOS and gralloc on non ChromeOS
> > platform. The allocated FrameBuffer owns the underlying buffer
> > but must be destroyed before PlatformFrameBufferAllocator is
> > destroyed.
> >
> > Signed-off-by: Hirokazu Honda <hiroh at chromium.org>
> > Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> > ---
> >  src/android/frame_buffer_allocator.h          |  54 +++++++
> >  .../mm/cros_frame_buffer_allocator.cpp        |  88 +++++++++++
> >  .../mm/generic_frame_buffer_allocator.cpp     | 142 ++++++++++++++++++
> >  src/android/mm/meson.build                    |   6 +-
> >  4 files changed, 288 insertions(+), 2 deletions(-)
> >  create mode 100644 src/android/frame_buffer_allocator.h
> >  create mode 100644 src/android/mm/cros_frame_buffer_allocator.cpp
> >  create mode 100644 src/android/mm/generic_frame_buffer_allocator.cpp
> >
> > diff --git a/src/android/frame_buffer_allocator.h b/src/android/frame_buffer_allocator.h
> > new file mode 100644
> > index 00000000..41ed4ae1
> > --- /dev/null
> > +++ b/src/android/frame_buffer_allocator.h
> > @@ -0,0 +1,54 @@
> > +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> > +/*
> > + * Copyright (C) 2021, Google Inc.
> > + *
> > + * frame_buffer_allocator.h - Interface definition to allocate Frame buffer in
> > + * platform dependent way.
> > + */
> > +#ifndef __ANDROID_FRAME_BUFFER_ALLOCATOR_H__
> > +#define __ANDROID_FRAME_BUFFER_ALLOCATOR_H__
> > +
> > +#include <memory>
> > +
> > +#include <libcamera/base/class.h>
>
> checkstyle should have suggested you a separate group ?
> It didn't for me recently but I got told so :)
>

I don't get any error.

> > +#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();
> > +
> > +     /*
> > +      * FrameBuffer owns the underlying buffer. Returns nullptr on failure.
> > +      * Note: The returned FrameBuffer needs to be destroyed before
> > +      * PlatformFrameBufferAllocator is destroyed.
> > +      */
> > +     std::unique_ptr<libcamera::FrameBuffer> allocate(
> > +             int halPixelFormat, const libcamera::Size &size, uint32_t usage);
> > +};
> > +
> > +#define PUBLIC_FRAME_BUFFER_ALLOCATOR_IMPLEMENTATION                 \
> > +PlatformFrameBufferAllocator::PlatformFrameBufferAllocator(          \
> > +     CameraDevice *const cameraDevice)                               \
> > +     : Extensible(std::make_unique<Private>(this, cameraDevice))     \
> > +{                                                                    \
> > +}                                                                    \
> > +PlatformFrameBufferAllocator::~PlatformFrameBufferAllocator()                \
> > +{                                                                    \
> > +}                                                                    \
> > +std::unique_ptr<libcamera::FrameBuffer>                                      \
> > +PlatformFrameBufferAllocator::allocate(int halPixelFormat,           \
> > +                                    const libcamera::Size& size,     \
> > +                                    uint32_t usage)                  \
> > +{                                                                    \
> > +     return _d()->allocate(halPixelFormat, size, usage);             \
> > +}
> > +
> > +#endif /* __ANDROID_FRAME_BUFFER_ALLOCATOR_H__ */
> > diff --git a/src/android/mm/cros_frame_buffer_allocator.cpp b/src/android/mm/cros_frame_buffer_allocator.cpp
> > new file mode 100644
> > index 00000000..d6343e53
> > --- /dev/null
> > +++ b/src/android/mm/cros_frame_buffer_allocator.cpp
> > @@ -0,0 +1,88 @@
> > +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> > +/*
> > + * Copyright (C) 2021, Google Inc.
> > + *
> > + * cros_frame_buffer.cpp - Allocate FrameBuffer for Chromium OS using
> > + * CameraBufferManager
> > + */
> > +
> > +#include <memory>
> > +#include <vector>
> > +
> > +#include <libcamera/base/log.h>
> > +
> > +#include "libcamera/internal/framebuffer.h"
> > +
> > +#include "../camera_device.h"
> > +#include "../frame_buffer_allocator.h"
>
> Blank line ?
>
> > +#include "cros-camera/camera_buffer_manager.h"
> > +
> > +using namespace libcamera;
> > +
> > +LOG_DECLARE_CATEGORY(HAL)
> > +
> > +namespace {
>
> Blank line
>
> > +class CrosFrameBufferData : public FrameBuffer::Private
> > +{
> > +     LIBCAMERA_DECLARE_PUBLIC(FrameBuffer)
>
> Blank line
>
> > +public:
> > +     CrosFrameBufferData(cros::ScopedBufferHandle scopedHandle)
> > +             : FrameBuffer::Private(), scopedHandle_(std::move(scopedHandle))
> > +     {
> > +     }
> > +
> > +     ~CrosFrameBufferData() override = default;
>
> Does the compiler complains if you don't force the destructor to be
> generated ?
>

No. Omitted.
> > +
> > +private:
> > +     cros::ScopedBufferHandle scopedHandle_;
> > +};
>
> Blank line
>
> > +} /* namespace */
> > +
> > +class PlatformFrameBufferAllocator::Private : public Extensible::Private
> > +{
> > +     LIBCAMERA_DECLARE_PUBLIC(PlatformFrameBufferAllocator)
> > +
> > +public:
> > +     Private([[maybe_unused]] PlatformFrameBufferAllocator *allocator,
>
> allocator is not used anymore in any of the two subclasses ? Can it be
> dropped ?
>

I think having PlatformAllocator in argument is required for
PFBAllocator::Private class constructor.

> > +             [[maybe_unused]] CameraDevice *const cameraDevice)
> > +     {
> > +     }
> > +
> > +     std::unique_ptr<libcamera::FrameBuffer> allocate(
> > +             int halPixelFormat, const libcamera::Size &size, uint32_t usage);
> > +};
> > +
> > +std::unique_ptr<libcamera::FrameBuffer>
> > +PlatformFrameBufferAllocator::Private::allocate(
> > +     int halPixelFormat, const libcamera::Size &size, uint32_t usage)
> > +{
> > +     cros::ScopedBufferHandle scopedHandle =
> > +             cros::CameraBufferManager::AllocateScopedBuffer(
> > +                     size.width, size.height, halPixelFormat, usage);
> > +     if (!scopedHandle) {
> > +             LOG(HAL, Error) << "Failed to allocate buffer handle";
> > +             return nullptr;
> > +     }
> > +
> > +     buffer_handle_t handle = *scopedHandle;
> > +     const size_t numPlanes = cros::CameraBufferManager::GetNumPlanes(handle);
> > +     std::vector<FrameBuffer::Plane> planes(numPlanes);
> > +     FileDescriptor fd{ handle->data[0] };
>
> afaict this duplicates the filedescriptor. If the
> cros:CameraBufferManager closes its copy on destruction, it's fine.
>

Yes, correct.

> > +     if (!fd.isValid()) {
> > +             LOG(HAL, Fatal) << "Invalid fd";
> > +             return nullptr;
> > +     }
> > +
> > +     /* This code assumes all the planes are located in the same buffer. */
> > +     for (auto [i, plane] : utils::enumerate(planes)) {
> > +             plane.fd = fd;
> > +             plane.offset = cros::CameraBufferManager::GetPlaneOffset(handle, i);
> > +             plane.length = cros::CameraBufferManager::GetPlaneSize(handle, i);
> > +     }
> > +
> > +     return std::make_unique<FrameBuffer>(
> > +             std::make_unique<CrosFrameBufferData>(std::move(scopedHandle)),
>
> DO you need to move scopedHandle ? You have a single constructor that
> will bind to && and & if I'm not mistaken.
>

Yes, I have to.  cros::ScopedBufferHandle is move-only constructor.
Google c++ coding style restricts using && in move constructor only.
I think since CrosFrameBufferData is different from
cros::ScopedBufferHandle this is not move constructor.

-Hiro

> With minors and the file descriptor duplication clarified
> Reviewed-by: Jacopo Mondi <jacopo at jmondi.org>
>
> Thanks
>   j
>
> > +             planes);
> > +}
> > +
> > +PUBLIC_FRAME_BUFFER_ALLOCATOR_IMPLEMENTATION
> > diff --git a/src/android/mm/generic_frame_buffer_allocator.cpp b/src/android/mm/generic_frame_buffer_allocator.cpp
> > new file mode 100644
> > index 00000000..f00fd704
> > --- /dev/null
> > +++ b/src/android/mm/generic_frame_buffer_allocator.cpp
> > @@ -0,0 +1,142 @@
> > +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> > +/*
> > + * Copyright (C) 2021, Google Inc.
> > + *
> > + * generic_camera_buffer.cpp - Allocate FrameBuffer using gralloc API
> > + */
> > +
> > +#include <memory>
> > +#include <vector>
> > +
> > +#include <libcamera/base/log.h>
> > +
> > +#include "libcamera/internal/formats.h"
> > +#include "libcamera/internal/framebuffer.h"
> > +
> > +#include <hardware/camera3.h>
> > +#include <hardware/gralloc.h>
> > +#include <hardware/hardware.h>
> > +
> > +#include "../camera_device.h"
> > +#include "../frame_buffer_allocator.h"
> > +
> > +using namespace libcamera;
> > +
> > +LOG_DECLARE_CATEGORY(HAL)
> > +
> > +namespace {
> > +class GenericFrameBufferData : public FrameBuffer::Private
> > +{
> > +     LIBCAMERA_DECLARE_PUBLIC(FrameBuffer)
> > +
> > +public:
> > +     GenericFrameBufferData(struct alloc_device_t *allocDevice,
> > +                            buffer_handle_t handle)
> > +             : 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.
> > +              *
> > +              * \todo Thread safety against alloc_device_t is not documented.
> > +              * Is it no problem to call alloc/free in parallel?
> > +              */
> > +             allocDevice_->free(allocDevice_, handle_);
> > +     }
> > +
> > +private:
> > +     struct alloc_device_t *allocDevice_;
> > +     const buffer_handle_t handle_;
> > +};
> > +} /* namespace */
> > +
> > +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_(nullptr)
> > +     {
> > +             ASSERT(hardwareModule_);
> > +     }
> > +
> > +     ~Private() override;
> > +
> > +     std::unique_ptr<libcamera::FrameBuffer> allocate(
> > +             int halPixelFormat, const libcamera::Size &size, uint32_t usage);
> > +
> > +private:
> > +     const CameraDevice *const cameraDevice_;
> > +     struct hw_module_t *const hardwareModule_;
> > +     struct alloc_device_t *allocDevice_;
> > +};
> > +
> > +PlatformFrameBufferAllocator::Private::~Private()
> > +{
> > +     if (allocDevice_)
> > +             gralloc_close(allocDevice_);
> > +}
> > +
> > +std::unique_ptr<libcamera::FrameBuffer>
> > +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;
> > +     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 allocating: " << ret;
> > +             return nullptr;
> > +     }
> > +     if (!handle) {
> > +             LOG(HAL, Fatal) << "buffer_handle_t is empty on success";
> > +             return nullptr;
> > +     }
> > +
> > +     const libcamera::PixelFormat pixelFormat =
> > +             cameraDevice_->capabilities()->toPixelFormat(halPixelFormat);
> > +     const auto &info = PixelFormatInfo::info(pixelFormat);
> > +     std::vector<FrameBuffer::Plane> planes(info.numPlanes());
> > +
> > +     /* This code assumes the planes are mapped consecutively. */
> > +     FileDescriptor fd{ handle->data[0] };
> > +     size_t offset = 0;
> > +     for (auto [i, plane] : utils::enumerate(planes)) {
> > +             const size_t planeSize = info.planeSize(size.height, i, stride);
> > +
> > +             planes[i].fd = fd;
> > +             planes[i].offset = offset;
> > +             planes[i].length = planeSize;
> > +             offset += planeSize;
> > +     }
> > +
> > +     return std::make_unique<FrameBuffer>(
> > +             std::make_unique<GenericFrameBufferData>(allocDevice_, handle),
> > +             planes);
> > +}
> > +
> > +PUBLIC_FRAME_BUFFER_ALLOCATOR_IMPLEMENTATION
> > diff --git a/src/android/mm/meson.build b/src/android/mm/meson.build
> > index eeb5cc2e..d40a3b0b 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_allocator.cpp'])
> >  elif platform == 'cros'
> > -    android_hal_sources += files(['cros_camera_buffer.cpp'])
> > +    android_hal_sources += files(['cros_camera_buffer.cpp',
> > +                                  'cros_frame_buffer_allocator.cpp'])
> >      android_deps += [dependency('libcros_camera')]
> >  endif
> > --
> > 2.34.0.rc2.393.gf8c9666880-goog
> >


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