skyline/app/src/main/cpp/skyline/soc/host1x/syncpoint.h

// SPDX-License-Identifier: MPL-2.0
// Copyright © 2020 Skyline Team and Contributors (https://github.com/skyline-emu/)
// Copyright © 2020 Ryujinx Team and Contributors

#pragma once

#include <common.h>

namespace skyline::soc::host1x {
    constexpr size_t SyncpointCount{192}; //!< The number of host1x syncpoints on T210

    /**
     * @brief The Syncpoint class represents a single syncpoint in the GPU which is used for GPU -> CPU synchronisation
     */
    class Syncpoint {
      private:
        struct Waiter {
            u32 threshold; //!< The syncpoint value to wait on to be reached
            std::function<void()> callback; //!< The callback to do after the wait has ended
        };

        std::mutex waiterLock; //!< Synchronizes insertions and deletions of waiters
        std::map<u64, Waiter> waiterMap;
        u64 nextWaiterId{1};

      public:
        std::atomic<u32> value{};

        /**
         * @brief Registers a new waiter with a callback that will be called when the syncpoint reaches the target threshold
         * @note The callback will be called immediately if the syncpoint has already reached the given threshold
         * @return A persistent identifier that can be used to refer to the waiter, or 0 if the threshold has already been reached
         */
        u64 RegisterWaiter(u32 threshold, const std::function<void()> &callback);

        /**
         * @brief Removes a waiter given by 'id' from the pending waiter map
         */
        void DeregisterWaiter(u64 id);

        /**
         * @brief Increments the syncpoint by 1
         * @return The new value of the syncpoint
         */
        u32 Increment();

        /**
         * @brief Waits for the syncpoint to reach given threshold
         * @return If the wait was successful (true) or timed out (false)
         * @note Guaranteed to succeed when 'steady_clock::duration::max()' is used
         */
        bool Wait(u32 threshold, std::chrono::steady_clock::duration timeout);
    };
}