system/dev/lib/mt8167/include/soc/mt8167/mt8167-audio-out.h

// Copyright 2019 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.

#pragma once

#include <assert.h>
#include <memory>
#include <utility>

#include <ddktl/mmio.h>

class MtAudioOutDevice {

public:
    enum MtI2sCh {
        I2S2, // Primary.
        I2S4, // Secondary.
    };

    DISALLOW_COPY_ASSIGN_AND_MOVE(MtAudioOutDevice);

    static std::unique_ptr<MtAudioOutDevice> Create(ddk::MmioBuffer mmio, MtI2sCh ch);

    // Sets the buffer/length pointers for the DMA engine,
    // must reside in the lower 32-bits of the address space.
    zx_status_t SetBuffer(zx_paddr_t buf, size_t len);

    // Returns offset of dma pointer in the ring buffer.
    uint32_t GetRingPosition();

    // Starts clocking data with data fetched from the beginning of the buffer.
    uint64_t Start();

    // Stops clocking data out (physical bus signals remain active).
    void Stop();

    // Stops clocking data and quiets output signals.
    void Shutdown();

    uint32_t fifo_depth() const { return fifo_depth_; };

private:
    const uint32_t fifo_depth_; // in bytes.
    ddk::MmioBuffer mmio_;

    // TODO(andresoportus): Add more configuration options.
    MtAudioOutDevice(ddk::MmioBuffer mmio, uint32_t fifo_depth)
        : fifo_depth_(fifo_depth),
          mmio_(std::move(mmio)){};

    void InitRegs();
};