[PATCH v7 03/18] libcamera: dma_heaps: extend DmaHeap class to support system heap
Milan Zamazal
mzamazal at redhat.com
Thu Apr 4 10:46:40 CEST 2024
From: Andrey Konovalov <andrey.konovalov at 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 at linaro.org> # sc8280xp Lenovo x13s
Tested-by: Pavel Machek <pavel at ucw.cz>
Reviewed-by: Milan Zamazal <mzamazal at redhat.com>
Reviewed-by: Pavel Machek <pavel at ucw.cz>
Signed-off-by: Andrey Konovalov <andrey.konovalov at linaro.org>
Signed-off-by: Hans de Goede <hdegoede at 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
+ */
+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
*
- * 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;
}
--
2.42.0
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