src/android/mm/allocator.h

// Copyright 2024 The ChromiumOS Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CAMERA_HARDWARE_BUFFER_ALLOCATOR_H_
#define CAMERA_HARDWARE_BUFFER_ALLOCATOR_H_

#include <cstddef>
#include <cstdint>
#include <drm_fourcc.h>
#include <memory>

namespace crosLibcamera {

constexpr int kMaxPlanes = 4;

struct PlaneDescriptor {
	int size = 0;
	int offset = 0;
	int pixel_stride = 0;
	int row_stride = 0;
};

struct BufferDescriptor {
	uint32_t drm_format = DRM_FORMAT_INVALID;
	int width = 0;
	int height = 0;
	uint32_t gbm_flags = 0;
	int num_planes = 0;
	uint64_t format_modifier = DRM_FORMAT_MOD_INVALID;
	PlaneDescriptor planes[kMaxPlanes];
};

struct ImportData {
	BufferDescriptor desc;
	int plane_fd[kMaxPlanes];
};

// Buffer sync type for read, write or read/write.
enum class SyncType {
	kSyncRead,
	kSyncWrite,
	kSyncReadWrite,
};

// The buffer allocator interface.
class Allocator
{
public:
	// The actual backend handling the buffer allocation and synchronization.
	enum class Backend {
		// Minigbm backed by graphics DRM drivers.
		kMinigbm,
	};

	static std::unique_ptr<Allocator> Create(Backend backend);

	// BufferObject interface used to manage and access the backing storage
	// allocated for a buffer.
	class BufferObject
	{
	public:
		virtual ~BufferObject() = default;
		virtual BufferDescriptor Describe() const = 0;
		virtual bool BeginCpuAccess(SyncType sync_type, int plane) = 0;
		virtual bool EndCpuAccess(SyncType sync_type, int plane) = 0;
		virtual bool Map(int plane) = 0;
		virtual void Unmap(int plane) = 0;
		virtual int GetPlaneFd(int plane) const = 0;
		virtual void *GetPlaneAddr(int plane) const = 0;
		virtual uint64_t GetId() const = 0;
	};

	virtual ~Allocator() = default;
	virtual std::unique_ptr<BufferObject> CreateBo(int width,
						       int height,
						       uint32_t drm_format,
						       uint32_t gbm_flags) = 0;
	virtual std::unique_ptr<BufferObject> ImportBo(const ImportData &data) = 0;
	virtual bool IsFormatSupported(uint32_t drm_format, uint32_t gbm_flags) = 0;
};

} // namespace crosLibcamera

#endif // CAMERA_HARDWARE_BUFFER_ALLOCATOR_H_