src/android/mm/minigbm_allocator.cpp

// 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.

#include "minigbm_allocator.h"

#include <gbm.h>
#include <unistd.h>

#include <libcamera/base/log.h>

#if HAVE_ANDROID_OS
#include <minigbm_helpers.h>
#else
#include <minigbm/minigbm_helpers.h>
#endif
#include <memory>
#include <sys/mman.h>
#include <utility>

#include "allocator.h"

#define CHECK(...)
#define CHECK_NE(...)
#define CHECK_LT(...)

using namespace libcamera;

LOG_DECLARE_CATEGORY(HAL)

namespace crosLibcamera {

namespace {

uint32_t SyncTypeToGbmTransferFlag(SyncType sync_type)
{
	switch (sync_type) {
	case SyncType::kSyncRead:
		return GBM_BO_TRANSFER_READ;
	case SyncType::kSyncWrite:
		return GBM_BO_TRANSFER_WRITE;
	case SyncType::kSyncReadWrite:
		return GBM_BO_TRANSFER_READ_WRITE;
	}
}

} // namespace

MinigbmAllocator::BufferObject::BufferObject(struct gbm_bo *bo,
					     uint32_t gbm_flags)
	: bo_(bo)
{
	CHECK_NE(bo_, nullptr);

	desc_ = {
		.drm_format = gbm_bo_get_format(bo_),
		.width = static_cast<int>(gbm_bo_get_width(bo_)),
		.height = static_cast<int>(gbm_bo_get_height(bo_)),
		.gbm_flags = gbm_flags,
		.num_planes = gbm_bo_get_plane_count(bo_),
		.format_modifier = gbm_bo_get_modifier(bo_),
	};
	for (int i = 0; i < desc_.num_planes; ++i) {
		desc_.planes[i] = {
			.size = static_cast<int>(gbm_bo_get_plane_size(bo_, i)),
			.offset = static_cast<int>(gbm_bo_get_offset(bo_, i)),
			// Should this be per-plane?
			.pixel_stride = static_cast<int>(gbm_bo_get_bpp(bo_)),
			.row_stride = static_cast<int>(gbm_bo_get_stride_for_plane(bo_, i)),
		};
	}
}

MinigbmAllocator::BufferObject::BufferObject(BufferObject &&other)
{
	(*this) = std::move(other);
}

MinigbmAllocator::BufferObject &MinigbmAllocator::BufferObject::operator=(
	BufferObject &&other)
{
	if (this != &other) {
		Invalidate();
		this->bo_ = other.bo_;
		this->plane_data_ = other.plane_data_;
		this->desc_ = other.desc_;
		other.bo_ = nullptr;
		for (int i = 0; i < kMaxPlanes; ++i) {
			other.plane_data_[i] = { .map_data = nullptr, .addr = nullptr };
		}
		other.desc_ = BufferDescriptor();
	}
	return *this;
}

MinigbmAllocator::BufferObject::~BufferObject()
{
	Invalidate();
}

BufferDescriptor MinigbmAllocator::BufferObject::Describe() const
{
	return desc_;
}

bool MinigbmAllocator::BufferObject::BeginCpuAccess(SyncType sync_type,
						    int plane)
{
	CHECK_NE(bo_, nullptr);
	CHECK_LT(plane, desc_.num_planes);
	if (IsMapped(plane)) {
		Unmap(plane);
	}
	return MapInternal(sync_type, plane);
}

bool MinigbmAllocator::BufferObject::EndCpuAccess(SyncType sync_type,
						  int plane)
{
	CHECK_NE(bo_, nullptr);
	CHECK_LT(plane, desc_.num_planes);
	if (IsMapped(plane)) {
		Unmap(plane);
		return MapInternal(sync_type, plane);
	}
	return true;
}

bool MinigbmAllocator::BufferObject::Map(int plane)
{
	CHECK_NE(bo_, nullptr);
	CHECK_LT(plane, desc_.num_planes);
	return MapInternal(SyncType::kSyncReadWrite, plane);
}

void MinigbmAllocator::BufferObject::Unmap(int plane)
{
	CHECK_NE(bo_, nullptr);
	CHECK_LT(plane, desc_.num_planes);
	UnmapInternal(plane);
}

int MinigbmAllocator::BufferObject::GetPlaneFd(int plane) const
{
	CHECK_NE(bo_, nullptr);
	CHECK_LT(plane, desc_.num_planes);
	return gbm_bo_get_plane_fd(bo_, plane);
}

void *MinigbmAllocator::BufferObject::GetPlaneAddr(int plane) const
{
	CHECK_NE(bo_, nullptr);
	CHECK_LT(plane, desc_.num_planes);
	if (!IsMapped(plane)) {
		LOG(HAL, Error) << "Buffer 0x" << std::hex << GetId() << " is not mapped";
		return nullptr;
	}
	return plane_data_[plane].addr;
}

uint64_t MinigbmAllocator::BufferObject::GetId() const
{
	CHECK_NE(bo_, nullptr);
	return reinterpret_cast<uint64_t>(bo_);
}

bool MinigbmAllocator::BufferObject::MapInternal(SyncType sync_type,
						 int plane)
{
	if (IsMapped(plane)) {
		return true;
	}
	uint32_t stride = 0;
	void *addr =
		gbm_bo_map2(bo_, 0, 0, gbm_bo_get_width(bo_), gbm_bo_get_height(bo_),
			    SyncTypeToGbmTransferFlag(sync_type), &stride,
			    &plane_data_[plane].map_data, plane);
	if (addr == MAP_FAILED) {
		LOG(HAL, Error) << "Failed to map buffer";
		plane_data_[plane].map_data = nullptr;
		return false;
	}
	plane_data_[plane].addr = addr;
	return true;
}

void MinigbmAllocator::BufferObject::UnmapInternal(int plane)
{
	if (!IsMapped(plane)) {
		return;
	}
	if (plane_data_[plane].map_data) {
		gbm_bo_unmap(bo_, plane_data_[plane].map_data);
	}
	plane_data_[plane].map_data = nullptr;
	plane_data_[plane].addr = nullptr;
}

bool MinigbmAllocator::BufferObject::IsMapped(int plane) const
{
	CHECK_NE(bo_, nullptr);
	CHECK_LT(plane, desc_.num_planes);
	return plane_data_[plane].map_data != nullptr &&
	       plane_data_[plane].addr != nullptr;
}

void MinigbmAllocator::BufferObject::Invalidate()
{
	if (bo_) {
		for (size_t i = 0; i < desc_.num_planes; ++i) {
			Unmap(i);
		}
		gbm_bo_destroy(bo_);
		bo_ = nullptr;
	}
}

MinigbmAllocator::MinigbmAllocator(struct gbm_device *gbm_device)
	: gbm_device_(gbm_device)
{
	CHECK(gbm_device_);
}

MinigbmAllocator::~MinigbmAllocator()
{
	close(gbm_device_get_fd(gbm_device_));
	gbm_device_destroy(gbm_device_);
}

std::unique_ptr<Allocator::BufferObject> MinigbmAllocator::CreateBo(
	int width, int height, uint32_t drm_format, uint32_t gbm_flags)
{
	return std::make_unique<BufferObject>(
		gbm_bo_create(gbm_device_, width, height, drm_format, gbm_flags),
		gbm_flags);
}

std::unique_ptr<Allocator::BufferObject> MinigbmAllocator::ImportBo(
	const ImportData &data)
{
	auto &desc = data.desc;
	struct gbm_import_fd_modifier_data import_data = {
		.width = static_cast<uint32_t>(desc.width),
		.height = static_cast<uint32_t>(desc.height),
		.format = desc.drm_format,
		.num_fds = static_cast<uint32_t>(desc.num_planes),
		.modifier = desc.format_modifier,
	};
	for (size_t i = 0; i < desc.num_planes; ++i) {
		import_data.fds[i] = data.plane_fd[i];
		import_data.strides[i] = desc.planes[i].row_stride;
		import_data.offsets[i] = desc.planes[i].offset;
	}
	return std::make_unique<BufferObject>(
		gbm_bo_import(gbm_device_, GBM_BO_IMPORT_FD_MODIFIER, &import_data,
			      desc.gbm_flags),
		desc.gbm_flags);
}

bool MinigbmAllocator::IsFormatSupported(uint32_t drm_format,
					 uint32_t gbm_flags)
{
	return gbm_device_is_format_supported(gbm_device_, drm_format, gbm_flags);
}

std::unique_ptr<Allocator> CreateMinigbmAllocator()
{
	int unused_fd = -1;
	struct gbm_device *gbm_device = minigbm_create_default_device(&unused_fd);
	if (!gbm_device) {
		LOG(HAL, Error) << "Minigbm not supported";
		return nullptr;
	}
	return std::make_unique<MinigbmAllocator>(gbm_device);
}

} // namespace crosLibcamera