// Copyright 2018 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.

#include <fbl/algorithm.h>
#include <fbl/alloc_checker.h>
#include <fbl/limits.h>
#include <fbl/unique_ptr.h>
#include <math.h>
#include <zxcpp/new.h>

#include "hdmitx.h"
#include "vim-audio.h"
#include "vim-display.h"

namespace audio {
namespace vim2 {

// Create a ring buffer large enough to hold 1 second of 48kHz stereo 16-bit
// audio.
//
// TODO(johngro): Look into what it would take to remove the restriction that
// this buffer be contiguous so that we can more easily map the buffer on the
// fly without needing to take precious contiguous memory.
constexpr size_t SPDIF_RB_SIZE = fbl::round_up<size_t, size_t>(48000 * 2 * 2u, PAGE_SIZE);

Vim2Audio::~Vim2Audio() {
}

zx_status_t Vim2Audio::Init(const platform_device_protocol_t* pdev) {
    zx_status_t res;

    // Get a hold of our registers.
    regs_ = Registers::Create(pdev, MMIO_AUD_OUT, &res);
    if (res != ZX_OK) {
        DISP_ERROR("Error mapping registers (mmio_id %u, res %d)\n", MMIO_AUD_OUT, res);
        return res;
    }
    ZX_DEBUG_ASSERT(regs_ != nullptr);

    // Place the various units into reset
    //
    // TODO(johngro): Add I2S to this list, right now we are only managing SPDIF
    Vim2SpdifAudioStream::Disable(*regs_);

    // Obtain our BTI from the platform manager
    res = pdev_get_bti(pdev, 0, audio_bti_.reset_and_get_address());
    if (res != ZX_OK) {
        DISP_ERROR("Failed to get audio BTI handle! (res = %d)\n", res);
        return res;
    }

    // Now that we have our BTI, and we have quiesced our hardware, we can
    // release any quarantined VMOs which may be lingering from a previous
    // crash.  Note, it should be impossible for this to fail.
    res = audio_bti_.release_quarantine();
    ZX_DEBUG_ASSERT(res == ZX_OK);

    // Allocate the buffer we will use for SPDIF
    //
    // TODO(johngro): How do we guarantee that this memory's phys location is
    // below the 4GB mark?
    zx::vmo spdif_rb_vmo;
    res = zx_vmo_create_contiguous(audio_bti_.get(),
                                   SPDIF_RB_SIZE,
                                   0,
                                   spdif_rb_vmo.reset_and_get_address());
    if (res != ZX_OK) {
        DISP_ERROR("Failed to allocate %zu byte ring buffer! (res = %d)\n", SPDIF_RB_SIZE, res);
        return res;
    }

    spdif_rb_vmo_ = RefCountedVmo::Create(fbl::move(spdif_rb_vmo));
    if (spdif_rb_vmo_ == nullptr) {
        DISP_ERROR("Failed to allocate RefCountedVmo\n");
        return ZX_ERR_NO_MEMORY;
    }

    return ZX_OK;
}

void Vim2Audio::OnDisplayAdded(const vim2_display_t* display, uint64_t display_id) {
    if (spdif_stream_ != nullptr) {
        ZX_DEBUG_ASSERT(spdif_stream_->display_id() != display_id);
        return;
    }

    // Start by checking our EDID to see if it has basic audio support.  If it
    // does not, then there is no point in continuing.
    //
    // TODO(johngro): this check could be more rigorous.  There is no
    // requirement that the CEA E-EDID block be block 1; in theory it could show
    // up in a later block.  Right now, we are assuming that code above us has
    // verified that, if there is a second block, that it is a valid CEA block.
    if ((display->edid_buf == nullptr) || (display->edid_length < 256)) {
        zxlogf(INFO, "Display EDID either missing or too short to contain CEA block.  "
                     "Skipping audio (len %hu)\n", display->edid_length);
        return;
    }

    // TODO(johngro): I'd say that I should clean up this magic number garbage,
    // but stevensd@ is currently working on more forma EDID parsing code.
    // Eventually, this code should be driven by the results of his parse,
    // instead of dealing with the encoding directly.
    //
    // At any rate, support for basic audio is signalled in bit 6 of byte 3 in
    // the CEA EDID block.  Displays are *required* to set this bit and support
    // stereo, 16 bit, 48k audio if the support any audio at all, so it is an
    // easy check.
    const uint8_t* cea_block = display->edid_buf + 128;
    if (!(cea_block[3] & (1u << 6))) {
        zxlogf(INFO, "Display does not indicate support for basic audio.\n");
        return;
    }

    if (!display->p) {
        zxlogf(WARN, "HDMI parameters are not set up.  Cannot enable audio!\n");
        return;
    }

    // Pin our VMO so that HW can access it.
    fzl::PinnedVmo pinned_spdif_rb;
    zx_status_t res;
    res = pinned_spdif_rb.Pin(spdif_rb_vmo_->vmo(), audio_bti_, ZX_VM_PERM_READ);
    if (res != ZX_OK) {
        DISP_ERROR("Failed to pin %zu byte ring buffer! (res = %d)\n", SPDIF_RB_SIZE, res);
        return;
    }

    // Sanity check the pinned VMO.
    if (pinned_spdif_rb.region_count() != 1) {
        DISP_ERROR("Audio ring buffer VMO is not contiguous! (regions = %u)\n",
                   pinned_spdif_rb.region_count());
        return;
    }

    const auto& r = pinned_spdif_rb.region(0);
    if ((r.phys_addr + r.size - 1) > fbl::numeric_limits<uint32_t>::max()) {
        DISP_ERROR("Audio ring buffer VMO is not below 4GB! [0x%zx, 0x%zx]\n",
                   r.phys_addr,
                   r.phys_addr + r.size);
        return;
    }

    spdif_stream_ = SimpleAudioStream::Create<Vim2SpdifAudioStream>(display,
                                                                    regs_,
                                                                    spdif_rb_vmo_,
                                                                    fbl::move(pinned_spdif_rb),
                                                                    display_id);
}

void Vim2Audio::OnDisplayRemoved(uint64_t display_id) {
    if (spdif_stream_ && (spdif_stream_->display_id() == display_id)) {
        spdif_stream_->Shutdown();
        spdif_stream_ = nullptr;
    }
}

}  // namespace vim2
}  // namespace audio

extern "C" {

zx_status_t vim2_audio_create(const platform_device_protocol_t* pdev,
                              vim2_audio_t **out_audio) {
    ZX_DEBUG_ASSERT(pdev != nullptr);
    ZX_DEBUG_ASSERT(out_audio != nullptr);
    *out_audio = nullptr;

    if (*out_audio != nullptr) {
        return ZX_ERR_BAD_STATE;
    }

    fbl::AllocChecker ac;
    auto audio = fbl::make_unique_checked<audio::vim2::Vim2Audio>(&ac);
    if (!ac.check()) {
        return ZX_ERR_NO_MEMORY;
    }

    zx_status_t res = audio->Init(pdev);
    if (res != ZX_OK) {
        return res;
    }

    *out_audio = reinterpret_cast<vim2_audio_t*>(audio.release());
    return ZX_OK;
}

void vim2_audio_shutdown(vim2_audio_t** inout_audio) {
    ZX_DEBUG_ASSERT(inout_audio);
    delete reinterpret_cast<audio::vim2::Vim2Audio*>(*inout_audio);
    *inout_audio = nullptr;
}

void vim2_audio_on_display_added(const vim2_display_t* display, uint64_t display_id) {
    if (!display->audio) {
        zxlogf(WARN, "Failed to add audio stream; missing Vim2Audio instance!\n");
        return;
    }

    auto cpp_audio = reinterpret_cast<audio::vim2::Vim2Audio*>(display->audio);
    cpp_audio->OnDisplayAdded(display, display_id);
}

void vim2_audio_on_display_removed(const vim2_display_t* display, uint64_t display_id) {
    if (!display->audio) {
        zxlogf(WARN, "Failed to add audio stream; missing Vim2Audio instance!\n");
        return;
    }

    auto cpp_audio = reinterpret_cast<audio::vim2::Vim2Audio*>(display->audio);
    cpp_audio->OnDisplayRemoved(display_id);
}

}  // extern "C"