drivers/gpu/msd-intel-gen/src/forcewake.h

// Copyright 2016 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef FORCEWAKE_H
#define FORCEWAKE_H

#include "magma_util/macros.h"
#include "magma_util/register_io.h"
#include "registers.h"
#include <thread>

class ForceWake {
public:
    static void reset(magma::RegisterIo* reg_io, registers::ForceWake::Domain domain)
    {
        registers::ForceWake::reset(reg_io, domain);
    }

    static void request(magma::RegisterIo* reg_io, registers::ForceWake::Domain domain)
    {
        if (registers::ForceWake::read_status(reg_io, domain) & (1 << kThreadShift))
            return;
        DLOG("forcewake request");
        registers::ForceWake::write(reg_io, domain, 1 << kThreadShift, 1 << kThreadShift);
        wait(reg_io, domain, true);
    }

    static void release(magma::RegisterIo* reg_io, registers::ForceWake::Domain domain)
    {
        if ((registers::ForceWake::read_status(reg_io, domain) & (1 << kThreadShift)) == 0)
            return;
        DLOG("forcewake release");
        registers::ForceWake::write(reg_io, domain, 1 << kThreadShift, 0);
        wait(reg_io, domain, false);
    }

private:
    static void wait(magma::RegisterIo* reg_io, registers::ForceWake::Domain domain, bool set)
    {
        uint32_t status;
        for (unsigned int ms = 0; ms < kRetryMaxMs; ms++) {
            status = registers::ForceWake::read_status(reg_io, domain);
            if (((status >> kThreadShift) & 1) == (set ? 1 : 0))
                return;
            std::this_thread::sleep_for(std::chrono::milliseconds(1));
            DLOG("forcewake wait retrying");
        }
        DLOG("timed out waiting for forcewake, status 0x%x", status);
    }

    static constexpr uint32_t kThreadShift = 0;
    static constexpr uint32_t kRetryMaxMs = 3;

    friend class TestForceWake;
};

#endif // FORCEWAKE_H