libcamera: dma_heaps: extend DmaHeap class to support system heap

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>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Andrey Konovalov <andrey.konovalov@linaro.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

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 */