[v7,03/18] libcamera: dma_heaps: extend DmaHeap class to support system heap

19821 diff mbox series

From: Andrey Konovalov <andrey.konovalov@linaro.org>

Add an argument to the constructor to specify dma heaps type(s)
to use. Can be DmaHeapFlag::Cma and/or DmaHeapFlag::System.
By default DmaHeapFlag::Cma is used. If both DmaHeapFlag::Cma and
DmaHeapFlag::System are set, CMA heap is tried first.

Tested-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org> # sc8280xp Lenovo x13s
Tested-by: Pavel Machek <pavel@ucw.cz>
Reviewed-by: Milan Zamazal <mzamazal@redhat.com>
Reviewed-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrey Konovalov <andrey.konovalov@linaro.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 include/libcamera/internal/dma_heaps.h | 12 +++-
 src/libcamera/dma_heaps.cpp            | 76 +++++++++++++++++++++-----
 2 files changed, 73 insertions(+), 15 deletions(-)

Hi Milan and Andrey,

Thank you for the patch.

On Thu, Apr 04, 2024 at 10:46:40AM +0200, Milan Zamazal wrote:
> From: Andrey Konovalov <andrey.konovalov@linaro.org>
> 
> Add an argument to the constructor to specify dma heaps type(s)
> to use. Can be DmaHeapFlag::Cma and/or DmaHeapFlag::System.
> By default DmaHeapFlag::Cma is used. If both DmaHeapFlag::Cma and
> DmaHeapFlag::System are set, CMA heap is tried first.
> 
> Tested-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org> # sc8280xp Lenovo x13s
> Tested-by: Pavel Machek <pavel@ucw.cz>
> Reviewed-by: Milan Zamazal <mzamazal@redhat.com>
> Reviewed-by: Pavel Machek <pavel@ucw.cz>
> Signed-off-by: Andrey Konovalov <andrey.konovalov@linaro.org>
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> ---
>  include/libcamera/internal/dma_heaps.h | 12 +++-
>  src/libcamera/dma_heaps.cpp            | 76 +++++++++++++++++++++-----
>  2 files changed, 73 insertions(+), 15 deletions(-)
> 
> diff --git a/include/libcamera/internal/dma_heaps.h b/include/libcamera/internal/dma_heaps.h
> index cff8f140..80bf29e7 100644
> --- a/include/libcamera/internal/dma_heaps.h
> +++ b/include/libcamera/internal/dma_heaps.h
> @@ -9,6 +9,7 @@
>  
>  #include <stddef.h>
>  
> +#include <libcamera/base/flags.h>
>  #include <libcamera/base/unique_fd.h>
>  
>  namespace libcamera {
> @@ -16,7 +17,14 @@ namespace libcamera {
>  class DmaHeap
>  {
>  public:
> -	DmaHeap();
> +	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);
> @@ -25,4 +33,6 @@ private:
>  	UniqueFD dmaHeapHandle_;
>  };
>  
> +LIBCAMERA_FLAGS_ENABLE_OPERATORS(DmaHeap::DmaHeapFlag)
> +
>  } /* namespace libcamera */
> diff --git a/src/libcamera/dma_heaps.cpp b/src/libcamera/dma_heaps.cpp
> index 70da6f3a..2503e4c5 100644
> --- a/src/libcamera/dma_heaps.cpp
> +++ b/src/libcamera/dma_heaps.cpp
> @@ -19,9 +19,11 @@
>  
>  /**
>   * \file dma_heaps.cpp
> - * \brief CMA dma-heap allocator
> + * \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.
> @@ -29,40 +31,86 @@
>   * Annoyingly, should the cma heap size be specified on the kernel command line
>   * instead of DT, the heap gets named "reserved" instead.
>   */
> -static constexpr std::array<const char *, 2> heapNames = {
> -	"/dev/dma_heap/linux,cma",
> -	"/dev/dma_heap/reserved"
> +
> +/**
> + * \brief Specification of a heap info entry
> + */

As this structure is internal to the file, it shouldn't end up in
generated documentation. That was the point of my comment in v6, which I
haven't expressed clearly enough.

You can just replace the /** with /*, or also drop the \brief. Or
possibly drop the comments, I'm not sure they add much. Up to you.

> +struct DmaHeapInfo {
> +	/**
> +	 * \brief Flag to match for considering the entry
> +	 */
> +	DmaHeap::DmaHeapFlag type;
> +	/**
> +	 * \brief Path to a heap device
> +	 */
> +	const char *deviceNodeName;
>  };
>  
> -namespace libcamera {
> +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 CMA dma-heap allocations
> + * \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.
>   */
>  
>  /**
> - * \brief Construct a DmaHeap that owns a CMA dma-heap file descriptor
> + * \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

No space between "param" and "[in]".

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

>   *
> - * Looks for a CMA dma-heap device to use. If it fails to open any dma-heap
> - * device, an invalid DmaHeap object is constructed.
> + * 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.
>   *
> - * Check the new DmaHeap object with DmaHeap::isValid before using it.
> + * 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()
> +DmaHeap::DmaHeap(DmaHeapFlags type)
>  {
> -	for (const char *name : heapNames) {
> -		int ret = ::open(name, O_RDWR | O_CLOEXEC, 0);
> +	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 " << name << ": "
> +				<< "Failed to open " << info.deviceNodeName << ": "
>  				<< strerror(ret);
>  			continue;
>  		}
>  
> +		LOG(DmaHeap, Debug) << "Using " << info.deviceNodeName;
>  		dmaHeapHandle_ = UniqueFD(ret);
>  		break;
>  	}