[PATCH v2 3/5] libcamera: Rename DmaHeap class to DmaBufAllocator

Laurent Pinchart laurent.pinchart at ideasonboard.com
Sun Jun 2 01:24:22 CEST 2024


Hi Hans,

Thank you for the patch.

On Thu, May 30, 2024 at 07:15:58PM +0200, Hans de Goede wrote:
> Users of the DmaHeap class really just want some way to allocate
> dma-buffers from userspace. This can also be done by using /dev/udmabuf
> instead of using /dev/dma_heap/*.
> 
> Rename DmaHeap class to DmaBufAllocator in preparation of adding
> /dev/udmabuf support.
> 
> And update the DmaHeap class docs to match including replacing references
> to "dma-heap type" with "dma-buf provider".
> 
> This is a pure automated rename on the code ('s/DmaHeap/DmaBufAllocator/')
> + file renames + doc updates. There are no functional changes.
> 
> The DmaBufAllocator objects in vc4.cpp and software_isp.cpp are left named
> dmaHeap_ to keep the changes to those 2 files to a minimum.
> 
> Signed-off-by: Hans de Goede <hdegoede at redhat.com>
> ---
>  .../libcamera/internal/dma_buf_allocator.h    |  38 ++++
>  include/libcamera/internal/dma_heaps.h        |  38 ----
>  include/libcamera/internal/meson.build        |   2 +-
>  .../internal/software_isp/software_isp.h      |   4 +-
>  src/libcamera/dma_buf_allocator.cpp           | 159 +++++++++++++++++
>  src/libcamera/dma_heaps.cpp                   | 165 ------------------
>  src/libcamera/meson.build                     |   2 +-
>  src/libcamera/pipeline/rpi/vc4/vc4.cpp        |   4 +-
>  src/libcamera/software_isp/software_isp.cpp   |   5 +-
>  9 files changed, 206 insertions(+), 211 deletions(-)
>  create mode 100644 include/libcamera/internal/dma_buf_allocator.h
>  delete mode 100644 include/libcamera/internal/dma_heaps.h
>  create mode 100644 src/libcamera/dma_buf_allocator.cpp
>  delete mode 100644 src/libcamera/dma_heaps.cpp
> 
> diff --git a/include/libcamera/internal/dma_buf_allocator.h b/include/libcamera/internal/dma_buf_allocator.h
> new file mode 100644
> index 00000000..a881042e
> --- /dev/null
> +++ b/include/libcamera/internal/dma_buf_allocator.h
> @@ -0,0 +1,38 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2020, Raspberry Pi Ltd
> + *
> + * Helper class for dma-buf allocations.
> + */
> +
> +#pragma once
> +
> +#include <stddef.h>
> +
> +#include <libcamera/base/flags.h>
> +#include <libcamera/base/unique_fd.h>
> +
> +namespace libcamera {
> +
> +class DmaBufAllocator
> +{
> +public:
> +	enum class DmaBufAllocatorFlag {
> +		CmaHeap = 1 << 0,
> +		SystemHeap = 1 << 1,
> +	};
> +
> +	using DmaBufAllocatorFlags = Flags<DmaBufAllocatorFlag>;
> +
> +	DmaBufAllocator(DmaBufAllocatorFlags flags = DmaBufAllocatorFlag::CmaHeap);
> +	~DmaBufAllocator();
> +	bool isValid() const { return providerHandle_.isValid(); }
> +	UniqueFD alloc(const char *name, std::size_t size);
> +
> +private:
> +	UniqueFD providerHandle_;
> +};
> +
> +LIBCAMERA_FLAGS_ENABLE_OPERATORS(DmaBufAllocator::DmaBufAllocatorFlag)
> +
> +} /* namespace libcamera */
> diff --git a/include/libcamera/internal/dma_heaps.h b/include/libcamera/internal/dma_heaps.h
> deleted file mode 100644
> index f0a8aa5d..00000000
> --- a/include/libcamera/internal/dma_heaps.h
> +++ /dev/null
> @@ -1,38 +0,0 @@
> -/* SPDX-License-Identifier: LGPL-2.1-or-later */
> -/*
> - * Copyright (C) 2020, Raspberry Pi Ltd
> - *
> - * Helper class for dma-heap allocations.
> - */
> -
> -#pragma once
> -
> -#include <stddef.h>
> -
> -#include <libcamera/base/flags.h>
> -#include <libcamera/base/unique_fd.h>
> -
> -namespace libcamera {
> -
> -class DmaHeap
> -{
> -public:
> -	enum class DmaHeapFlag {
> -		Cma = 1 << 0,
> -		System = 1 << 1,
> -	};
> -
> -	using DmaHeapFlags = Flags<DmaHeapFlag>;
> -
> -	DmaHeap(DmaHeapFlags flags = DmaHeapFlag::Cma);
> -	~DmaHeap();
> -	bool isValid() const { return dmaHeapHandle_.isValid(); }
> -	UniqueFD alloc(const char *name, std::size_t size);
> -
> -private:
> -	UniqueFD dmaHeapHandle_;
> -};
> -
> -LIBCAMERA_FLAGS_ENABLE_OPERATORS(DmaHeap::DmaHeapFlag)
> -
> -} /* namespace libcamera */
> diff --git a/include/libcamera/internal/meson.build b/include/libcamera/internal/meson.build
> index 160fdc37..9713ea1c 100644
> --- a/include/libcamera/internal/meson.build
> +++ b/include/libcamera/internal/meson.build
> @@ -25,7 +25,7 @@ libcamera_internal_headers = files([
>      'device_enumerator.h',
>      'device_enumerator_sysfs.h',
>      'device_enumerator_udev.h',
> -    'dma_heaps.h',
> +    'dma_buf_allocator.h',
>      'formats.h',
>      'framebuffer.h',
>      'ipa_manager.h',
> diff --git a/include/libcamera/internal/software_isp/software_isp.h b/include/libcamera/internal/software_isp/software_isp.h
> index 7e9fae6a..c5338c05 100644
> --- a/include/libcamera/internal/software_isp/software_isp.h
> +++ b/include/libcamera/internal/software_isp/software_isp.h
> @@ -27,7 +27,7 @@
>  #include <libcamera/ipa/soft_ipa_proxy.h>
>  
>  #include "libcamera/internal/camera_sensor.h"
> -#include "libcamera/internal/dma_heaps.h"
> +#include "libcamera/internal/dma_buf_allocator.h"
>  #include "libcamera/internal/pipeline_handler.h"
>  #include "libcamera/internal/shared_mem_object.h"
>  #include "libcamera/internal/software_isp/debayer_params.h"
> @@ -91,7 +91,7 @@ private:
>  	Thread ispWorkerThread_;
>  	SharedMemObject<DebayerParams> sharedParams_;
>  	DebayerParams debayerParams_;
> -	DmaHeap dmaHeap_;
> +	DmaBufAllocator dmaHeap_;
>  
>  	std::unique_ptr<ipa::soft::IPAProxySoft> ipa_;
>  };
> diff --git a/src/libcamera/dma_buf_allocator.cpp b/src/libcamera/dma_buf_allocator.cpp
> new file mode 100644
> index 00000000..bc0d78ef
> --- /dev/null
> +++ b/src/libcamera/dma_buf_allocator.cpp
> @@ -0,0 +1,159 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2024, Red Hat Inc.
> + * Copyright (C) 2020, Raspberry Pi Ltd
> + *
> + * Helper class for dma-buf allocations.
> + */
> +
> +#include "libcamera/internal/dma_buf_allocator.h"
> +
> +#include <array>
> +#include <fcntl.h>
> +#include <sys/ioctl.h>
> +#include <unistd.h>
> +
> +#include <linux/dma-buf.h>
> +#include <linux/dma-heap.h>
> +
> +#include <libcamera/base/log.h>
> +
> +/**
> + * \file dma_buf_allocator.cpp
> + * \brief dma-buf allocator
> + */
> +
> +namespace libcamera {
> +
> +#ifndef __DOXYGEN__
> +struct DmaBufAllocatorInfo {
> +	DmaBufAllocator::DmaBufAllocatorFlag type;
> +	const char *deviceNodeName;
> +};
> +#endif
> +
> +static constexpr std::array<DmaBufAllocatorInfo, 3> providerInfos = { {
> +	/*
> +	 * /dev/dma_heap/linux,cma is the CMA dma-heap. When the cma heap size is
> +	 * specified on the kernel command line, this gets renamed to "reserved".
> +	 */
> +	{ DmaBufAllocator::DmaBufAllocatorFlag::CmaHeap, "/dev/dma_heap/linux,cma" },
> +	{ DmaBufAllocator::DmaBufAllocatorFlag::CmaHeap, "/dev/dma_heap/reserved" },
> +	{ DmaBufAllocator::DmaBufAllocatorFlag::SystemHeap, "/dev/dma_heap/system" },
> +} };
> +
> +LOG_DEFINE_CATEGORY(DmaBufAllocator)
> +
> +/**
> + * \class DmaBufAllocator
> + * \brief Helper class for dma-buf allocations
> + *
> + * This class wraps a userspace dma-buf provider selected at construction time,
> + * and exposes functions to allocate dma-buffers from this provider.
> + *
> + * Different providers may provide dma-buffers with different properties for
> + * the underlying memory.  Which providers are acceptable is specified through

s/  / /

> + * the type argument passed to the DmaBufAllocator() constructor.
> + */
> +
> +/**
> + * \enum DmaBufAllocator::DmaBufAllocatorFlag
> + * \brief Type of the dma-buf provider
> + * \var DmaBufAllocator::CmaHeap
> + * \brief Allocate from a CMA dma-heap, providing physically-contiguous memory
> + * \var DmaBufAllocator::SystemHeap
> + * \brief Allocate from the system dma-heap, using the page allocator
> + */
> +
> +/**
> + * \typedef DmaBufAllocator::DmaBufAllocatorFlags
> + * \brief A bitwise combination of DmaBufAllocator::DmaBufAllocatorFlag values
> + */
> +
> +/**
> + * \brief Construct a DmaBufAllocator of a given type
> + * \param[in] type The type(s) of the dma-buf providers to allocate from
> + *
> + * The dma-buf provider type is selected with the \a type parameter, which defaults
> + * to the CMA heap. If no provider of the given type can be accessed, the constructed
> + * DmaBufAllocator instance is invalid as indicated by the isValid() function.
> + *
> + * Multiple types can be selected by combining type flags, in which case the
> + * constructed DmaBufAllocator will match one of the types. If multiple requested
> + * types can work on the system, which provider is used is undefined.

Please wrap the text at 80 columns.

> + */
> +DmaBufAllocator::DmaBufAllocator(DmaBufAllocatorFlags type)
> +{
> +	for (const auto &info : providerInfos) {
> +		if (!(type & info.type))
> +			continue;
> +
> +		int ret = ::open(info.deviceNodeName, O_RDWR | O_CLOEXEC, 0);
> +		if (ret < 0) {
> +			ret = errno;
> +			LOG(DmaBufAllocator, Debug)
> +				<< "Failed to open " << info.deviceNodeName << ": "
> +				<< strerror(ret);
> +			continue;
> +		}
> +
> +		LOG(DmaBufAllocator, Debug) << "Using " << info.deviceNodeName;
> +		providerHandle_ = UniqueFD(ret);
> +		break;
> +	}
> +
> +	if (!providerHandle_.isValid())
> +		LOG(DmaBufAllocator, Error) << "Could not open any dma-buf provider";
> +}
> +
> +/**
> + * \brief Destroy the DmaBufAllocator instance
> + */
> +DmaBufAllocator::~DmaBufAllocator() = default;
> +
> +/**
> + * \fn DmaBufAllocator::isValid()
> + * \brief Check if the DmaBufAllocator instance is valid
> + * \return True if the DmaBufAllocator is valid, false otherwise
> + */
> +
> +/**
> + * \brief Allocate a dma-buf from the DmaBufAllocator
> + * \param [in] name The name to set for the allocated buffer
> + * \param [in] size The size of the buffer to allocate
> + *
> + * Allocates a dma-buf with read/write access.
> + *
> + * If the allocation fails, return an invalid UniqueFD.
> + *
> + * \return The UniqueFD of the allocated buffer
> + */
> +UniqueFD DmaBufAllocator::alloc(const char *name, std::size_t size)
> +{
> +	int ret;
> +
> +	if (!name)
> +		return {};
> +
> +	struct dma_heap_allocation_data alloc = {};
> +
> +	alloc.len = size;
> +	alloc.fd_flags = O_CLOEXEC | O_RDWR;
> +
> +	ret = ::ioctl(providerHandle_.get(), DMA_HEAP_IOCTL_ALLOC, &alloc);
> +	if (ret < 0) {
> +		LOG(DmaBufAllocator, Error) << "dma-heap allocation failure for " << name;

		LOG(DmaBufAllocator, Error)
			<< "dma-heap allocation failure for " << name;

> +		return {};
> +	}
> +
> +	UniqueFD allocFd(alloc.fd);
> +	ret = ::ioctl(allocFd.get(), DMA_BUF_SET_NAME, name);
> +	if (ret < 0) {
> +		LOG(DmaBufAllocator, Error) << "dma-heap naming failure for " << name;

Same here.

Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>

> +		return {};
> +	}
> +
> +	return allocFd;
> +}
> +
> +} /* namespace libcamera */
> diff --git a/src/libcamera/dma_heaps.cpp b/src/libcamera/dma_heaps.cpp
> deleted file mode 100644
> index d4cb880b..00000000
> --- a/src/libcamera/dma_heaps.cpp
> +++ /dev/null
> @@ -1,165 +0,0 @@
> -/* SPDX-License-Identifier: LGPL-2.1-or-later */
> -/*
> - * Copyright (C) 2020, Raspberry Pi Ltd
> - *
> - * Helper class for dma-heap allocations.
> - */
> -
> -#include "libcamera/internal/dma_heaps.h"
> -
> -#include <array>
> -#include <fcntl.h>
> -#include <sys/ioctl.h>
> -#include <unistd.h>
> -
> -#include <linux/dma-buf.h>
> -#include <linux/dma-heap.h>
> -
> -#include <libcamera/base/log.h>
> -
> -/**
> - * \file dma_heaps.cpp
> - * \brief dma-heap allocator
> - */
> -
> -namespace libcamera {
> -
> -/*
> - * /dev/dma_heap/linux,cma is the dma-heap allocator, which allows dmaheap-cma
> - * to only have to worry about importing.
> - *
> - * Annoyingly, should the cma heap size be specified on the kernel command line
> - * instead of DT, the heap gets named "reserved" instead.
> - */
> -
> -#ifndef __DOXYGEN__
> -struct DmaHeapInfo {
> -	DmaHeap::DmaHeapFlag type;
> -	const char *deviceNodeName;
> -};
> -#endif
> -
> -static constexpr std::array<DmaHeapInfo, 3> heapInfos = { {
> -	{ DmaHeap::DmaHeapFlag::Cma, "/dev/dma_heap/linux,cma" },
> -	{ DmaHeap::DmaHeapFlag::Cma, "/dev/dma_heap/reserved" },
> -	{ DmaHeap::DmaHeapFlag::System, "/dev/dma_heap/system" },
> -} };
> -
> -LOG_DEFINE_CATEGORY(DmaHeap)
> -
> -/**
> - * \class DmaHeap
> - * \brief Helper class for dma-heap allocations
> - *
> - * DMA heaps are kernel devices that provide an API to allocate memory from
> - * different pools called "heaps", wrap each allocated piece of memory in a
> - * dmabuf object, and return the dmabuf file descriptor to userspace. Multiple
> - * heaps can be provided by the system, with different properties for the
> - * underlying memory.
> - *
> - * This class wraps a DMA heap selected at construction time, and exposes
> - * functions to manage memory allocation.
> - */
> -
> -/**
> - * \enum DmaHeap::DmaHeapFlag
> - * \brief Type of the dma-heap
> - * \var DmaHeap::Cma
> - * \brief Allocate from a CMA dma-heap, providing physically-contiguous memory
> - * \var DmaHeap::System
> - * \brief Allocate from the system dma-heap, using the page allocator
> - */
> -
> -/**
> - * \typedef DmaHeap::DmaHeapFlags
> - * \brief A bitwise combination of DmaHeap::DmaHeapFlag values
> - */
> -
> -/**
> - * \brief Construct a DmaHeap of a given type
> - * \param[in] type The type(s) of the dma-heap(s) to allocate from
> - *
> - * The DMA heap type is selected with the \a type parameter, which defaults to
> - * the CMA heap. If no heap of the given type can be accessed, the constructed
> - * DmaHeap instance is invalid as indicated by the isValid() function.
> - *
> - * Multiple types can be selected by combining type flags, in which case the
> - * constructed DmaHeap will match one of the types. If the system provides
> - * multiple heaps that match the requested types, which heap is used is
> - * undefined.
> - */
> -DmaHeap::DmaHeap(DmaHeapFlags type)
> -{
> -	for (const auto &info : heapInfos) {
> -		if (!(type & info.type))
> -			continue;
> -
> -		int ret = ::open(info.deviceNodeName, O_RDWR | O_CLOEXEC, 0);
> -		if (ret < 0) {
> -			ret = errno;
> -			LOG(DmaHeap, Debug)
> -				<< "Failed to open " << info.deviceNodeName << ": "
> -				<< strerror(ret);
> -			continue;
> -		}
> -
> -		LOG(DmaHeap, Debug) << "Using " << info.deviceNodeName;
> -		dmaHeapHandle_ = UniqueFD(ret);
> -		break;
> -	}
> -
> -	if (!dmaHeapHandle_.isValid())
> -		LOG(DmaHeap, Error) << "Could not open any dmaHeap device";
> -}
> -
> -/**
> - * \brief Destroy the DmaHeap instance
> - */
> -DmaHeap::~DmaHeap() = default;
> -
> -/**
> - * \fn DmaHeap::isValid()
> - * \brief Check if the DmaHeap instance is valid
> - * \return True if the DmaHeap is valid, false otherwise
> - */
> -
> -/**
> - * \brief Allocate a dma-buf from the DmaHeap
> - * \param [in] name The name to set for the allocated buffer
> - * \param [in] size The size of the buffer to allocate
> - *
> - * Allocates a dma-buf with read/write access.
> - *
> - * If the allocation fails, return an invalid UniqueFD.
> - *
> - * \return The UniqueFD of the allocated buffer
> - */
> -UniqueFD DmaHeap::alloc(const char *name, std::size_t size)
> -{
> -	int ret;
> -
> -	if (!name)
> -		return {};
> -
> -	struct dma_heap_allocation_data alloc = {};
> -
> -	alloc.len = size;
> -	alloc.fd_flags = O_CLOEXEC | O_RDWR;
> -
> -	ret = ::ioctl(dmaHeapHandle_.get(), DMA_HEAP_IOCTL_ALLOC, &alloc);
> -	if (ret < 0) {
> -		LOG(DmaHeap, Error) << "dmaHeap allocation failure for " << name;
> -		return {};
> -	}
> -
> -	UniqueFD allocFd(alloc.fd);
> -	ret = ::ioctl(allocFd.get(), DMA_BUF_SET_NAME, name);
> -	if (ret < 0) {
> -		LOG(DmaHeap, Error) << "dmaHeap naming failure for " << name;
> -		return {};
> -	}
> -
> -	return allocFd;
> -}
> -
> -} /* namespace libcamera */
> diff --git a/src/libcamera/meson.build b/src/libcamera/meson.build
> index a3b12bc1..89504cee 100644
> --- a/src/libcamera/meson.build
> +++ b/src/libcamera/meson.build
> @@ -15,7 +15,7 @@ libcamera_sources = files([
>      'delayed_controls.cpp',
>      'device_enumerator.cpp',
>      'device_enumerator_sysfs.cpp',
> -    'dma_heaps.cpp',
> +    'dma_buf_allocator.cpp',
>      'fence.cpp',
>      'formats.cpp',
>      'framebuffer.cpp',
> diff --git a/src/libcamera/pipeline/rpi/vc4/vc4.cpp b/src/libcamera/pipeline/rpi/vc4/vc4.cpp
> index 37fb310f..4a89e35f 100644
> --- a/src/libcamera/pipeline/rpi/vc4/vc4.cpp
> +++ b/src/libcamera/pipeline/rpi/vc4/vc4.cpp
> @@ -12,7 +12,7 @@
>  #include <libcamera/formats.h>
>  
>  #include "libcamera/internal/device_enumerator.h"
> -#include "libcamera/internal/dma_heaps.h"
> +#include "libcamera/internal/dma_buf_allocator.h"
>  
>  #include "../common/pipeline_base.h"
>  #include "../common/rpi_stream.h"
> @@ -86,7 +86,7 @@ public:
>  	RPi::Device<Isp, 4> isp_;
>  
>  	/* DMAHEAP allocation helper. */
> -	DmaHeap dmaHeap_;
> +	DmaBufAllocator dmaHeap_;
>  	SharedFD lsTable_;
>  
>  	struct Config {
> diff --git a/src/libcamera/software_isp/software_isp.cpp b/src/libcamera/software_isp/software_isp.cpp
> index c9b6be56..b5eab670 100644
> --- a/src/libcamera/software_isp/software_isp.cpp
> +++ b/src/libcamera/software_isp/software_isp.cpp
> @@ -65,10 +65,11 @@ LOG_DEFINE_CATEGORY(SoftwareIsp)
>  SoftwareIsp::SoftwareIsp(PipelineHandler *pipe, const CameraSensor *sensor)
>  	: debayerParams_{ DebayerParams::kGain10, DebayerParams::kGain10,
>  			  DebayerParams::kGain10, 0.5f, 0 },
> -	  dmaHeap_(DmaHeap::DmaHeapFlag::Cma | DmaHeap::DmaHeapFlag::System)
> +	  dmaHeap_(DmaBufAllocator::DmaBufAllocatorFlag::CmaHeap |
> +		   DmaBufAllocator::DmaBufAllocatorFlag::SystemHeap)
>  {
>  	if (!dmaHeap_.isValid()) {
> -		LOG(SoftwareIsp, Error) << "Failed to create DmaHeap object";
> +		LOG(SoftwareIsp, Error) << "Failed to create DmaBufAllocator object";
>  		return;
>  	}
>  

-- 
Regards,

Laurent Pinchart


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