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Diffstat (limited to 'src/libcamera/dma_heaps.cpp')
-rw-r--r-- | src/libcamera/dma_heaps.cpp | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/src/libcamera/dma_heaps.cpp b/src/libcamera/dma_heaps.cpp new file mode 100644 index 00000000..e543045d --- /dev/null +++ b/src/libcamera/dma_heaps.cpp @@ -0,0 +1,124 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ +/* + * Copyright (C) 2020, Raspberry Pi Ltd + * + * dma_heaps.cpp - 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 CMA dma-heap allocator + */ + +/* + * /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. + */ +static constexpr std::array<const char *, 2> heapNames = { + "/dev/dma_heap/linux,cma", + "/dev/dma_heap/reserved" +}; + +namespace libcamera { + +LOG_DEFINE_CATEGORY(DmaHeap) + +/** + * \class DmaHeap + * \brief Helper class for CMA dma-heap allocations + */ + +/** + * \brief Construct a DmaHeap that owns a CMA dma-heap file descriptor + * + * Looks for a CMA dma-heap device to use. If it fails to open any dma-heap + * device, an invalid DmaHeap object is constructed. + * + * Check the new DmaHeap object with isValid before using it. + */ +DmaHeap::DmaHeap() +{ + for (const char *name : heapNames) { + int ret = ::open(name, O_RDWR | O_CLOEXEC, 0); + if (ret < 0) { + ret = errno; + LOG(DmaHeap, Debug) + << "Failed to open " << name << ": " + << strerror(ret); + continue; + } + + 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 */ |