media/codec2/vndk/include/C2DmaBufAllocator.h

/*
 * Copyright (C) 2020 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef STAGEFRIGHT_CODEC2_ALLOCATOR_BUF_H_
#define STAGEFRIGHT_CODEC2_ALLOCATOR_BUF_H_

#include <BufferAllocator/BufferAllocator.h>
#include <C2Buffer.h>
#include <sys/stat.h>  // stat

#include <functional>
#include <list>
#include <mutex>
#include <tuple>
#include <unordered_map>

namespace android {

class C2DmaBufAllocator : public C2Allocator {
   public:
    virtual c2_status_t newLinearAllocation(
            uint32_t capacity, C2MemoryUsage usage,
            std::shared_ptr<C2LinearAllocation>* allocation) override;

    virtual c2_status_t priorLinearAllocation(
            const C2Handle* handle, std::shared_ptr<C2LinearAllocation>* allocation) override;

    C2DmaBufAllocator(id_t id);

    virtual c2_status_t status() const { return mInit; }

    virtual bool checkHandle(const C2Handle* const o) const override { return CheckHandle(o); }

    static bool CheckHandle(const C2Handle* const o);

    virtual id_t getId() const override;

    virtual C2String getName() const override;

    virtual std::shared_ptr<const Traits> getTraits() const override;

    // Usage mapper function used by the allocator
    //   (usage, capacity) => (heapName, flags)
    //
    // capacity is aligned to the default block-size (defaults to page size) to
    // reduce caching overhead
    typedef std::function<c2_status_t(C2MemoryUsage, size_t,
                                      /* => */ C2String*, unsigned*)>
            UsageMapperFn;

    /**
     * Updates the usage mapper for subsequent new allocations, as well as the
     * supported minimum and maximum usage masks and default block-size to use
     * for the mapper.
     *
     * \param mapper          This method is called to map Codec 2.0 buffer usage
     *                        to dmabuf heap name and flags required by the dma
     *                        buf heap device
     *
     * \param minUsage        Minimum buffer usage required for supported
     *                        allocations (defaults to 0)
     *
     * \param maxUsage        Maximum buffer usage supported by the ion allocator
     *                        (defaults to SW_READ | SW_WRITE)
     *
     * \param blockSize       Alignment used prior to calling |mapper| for the
     *                        buffer capacity. This also helps reduce the size of
     *                        cache required for caching mapper results.
     *                        (defaults to the page size)
     */
    void setUsageMapper(const UsageMapperFn& mapper, uint64_t minUsage, uint64_t maxUsage,
                        uint64_t blockSize);

    static bool system_uncached_supported(void) {
        static int cached_result = -1;

        if (cached_result == -1) {
            struct stat buffer;
            cached_result = (stat("/dev/dma_heap/system-uncached", &buffer) == 0);
        }
        return (cached_result == 1);
    };

   private:
    c2_status_t mInit;
    BufferAllocator mBufferAllocator;

    c2_status_t mapUsage(C2MemoryUsage usage, size_t size,
                         /* => */ C2String* heap_name, unsigned* flags);

    // this locks mTraits, mBlockSize, mUsageMapper, mUsageMapperLru and
    // mUsageMapperCache
    mutable std::mutex mUsageMapperLock;
    std::shared_ptr<const Traits> mTraits;
    size_t mBlockSize;
    UsageMapperFn mUsageMapper;
    typedef std::pair<uint64_t, size_t> MapperKey;
    struct MapperKeyHash {
        std::size_t operator()(const MapperKey&) const;
    };
    typedef std::tuple<C2String, unsigned, c2_status_t> MapperValue;
    typedef std::pair<MapperKey, MapperValue> MapperKeyValue;
    typedef std::list<MapperKeyValue>::iterator MapperKeyValuePointer;
    std::list<MapperKeyValue> mUsageMapperLru;
    std::unordered_map<MapperKey, MapperKeyValuePointer, MapperKeyHash> mUsageMapperCache;
};
}  // namespace android

#endif  // STAGEFRIGHT_CODEC2_ALLOCATOR_BUF_H_