libcamera: Rename DmaHeap class to DmaBufAllocator

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.

Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Tested-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org> # Lenovo-x13s
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

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 */

include/libcamera/internal/dma_heaps.h

@@ -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 */

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',

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_;
 };

src/libcamera/dma_buf_allocator.cpp

@@ -0,0 +1,162 @@
+/* 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
+ * 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.
+ */
+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;
+		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;
+		return {};
+	}
+
+	return allocFd;
+}
+
+} /* namespace libcamera */

src/libcamera/dma_heaps.cpp

@@ -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 */

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',

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 {

src/libcamera/software_isp/software_isp.cpp

@@ -66,7 +66,8 @@ LOG_DEFINE_CATEGORY(SoftwareIsp)
  * handler
  */
 SoftwareIsp::SoftwareIsp(PipelineHandler *pipe, const CameraSensor *sensor)
-	: dmaHeap_(DmaHeap::DmaHeapFlag::Cma | DmaHeap::DmaHeapFlag::System)
+	: dmaHeap_(DmaBufAllocator::DmaBufAllocatorFlag::CmaHeap |
+		   DmaBufAllocator::DmaBufAllocatorFlag::SystemHeap)
 {
 	/*
 	 * debayerParams_ must be initialized because the initial value is used for
@@ -86,7 +87,7 @@ SoftwareIsp::SoftwareIsp(PipelineHandler *pipe, const CameraSensor *sensor)
 	}
 
 	if (!dmaHeap_.isValid()) {
-		LOG(SoftwareIsp, Error) << "Failed to create DmaHeap object";
+		LOG(SoftwareIsp, Error) << "Failed to create DmaBufAllocator object";
 		return;
 	}