// Copyright 2017 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 <dispatcher-pool/dispatcher-channel.h>
#include <dispatcher-pool/dispatcher-execution-domain.h>
#include <ddk/binding.h>
#include <ddk/driver.h>
#include <intel-hda/utils/intel-hda-registers.h>
#include <fbl/algorithm.h>
#include <fbl/alloc_checker.h>
#include <string.h>
#include <zircon/assert.h>
#include <zircon/device/intel-hda.h>
#include <zircon/process.h>
#include <lib/zx/channel.h>

#include "debug-logging.h"
#include "utils.h"

namespace audio {
namespace intel_hda {

fbl::RefPtr<fzl::VmarManager> DriverVmars::registers_;

zx_status_t DriverVmars::Initialize() {
    if (registers_ != nullptr) {
        return ZX_ERR_BAD_STATE;
    }

    // Create a compact VMAR to map all of our registers into.
    //
    // TODO(johngro): See ZX-1822 for details.
    //
    // Sizing right now is a bit of a guessing game.  A compact VMAR is not
    // going to perfectly tightly pack everything; it will still insert random
    // gaps in an attempt to get some minimum level of ASLR.  For now, I'm using
    // hardcoded guidance from teisenbe@ about how to size for the worst case.
    // If/when there is a better way of doing this, I need to come back and
    // switch to that.
    //
    // Formula being used here should be...
    // 2 * (total_region_size + (512k * (total_allocations - 1)))
    constexpr size_t MAX_SIZE_PER_CONTROLLER =
        sizeof(hda_all_registers_t) +
        MAPPED_CORB_RIRB_SIZE +
        (MAX_STREAMS_PER_CONTROLLER * MAPPED_BDL_SIZE) +
        sizeof(adsp_registers_t) +
        MAPPED_BDL_SIZE;

    // One alloc for the main registers, one for code loader BDL.
    constexpr size_t MAX_ALLOCS_PER_DSP = 2;
    // One alloc for the main registers, one for the CORB/RIRB, two for DSP,
    // and one for each possible stream BDL.
    constexpr size_t MAX_ALLOCS_PER_CONTROLLER = 2 + MAX_ALLOCS_PER_DSP +
                                                 MAX_STREAMS_PER_CONTROLLER;
    constexpr size_t MAX_CONTROLLERS = 4;
    constexpr size_t VMAR_SIZE = 2 *
        ((MAX_CONTROLLERS * MAX_SIZE_PER_CONTROLLER) +
        (((MAX_CONTROLLERS * MAX_ALLOCS_PER_CONTROLLER) - 1) * (512u << 10)));

    GLOBAL_LOG(TRACE, "Allocating 0x%zx byte VMAR for registers.\n", VMAR_SIZE);
    registers_ = fzl::VmarManager::Create(VMAR_SIZE);
    if (registers_ == nullptr) {
        return ZX_ERR_NO_MEMORY;
    }

    return ZX_OK;
}

void DriverVmars::Shutdown() {
    registers_.reset();
}

zx_status_t HandleDeviceIoctl(uint32_t op,
                              void* out_buf,
                              size_t out_len,
                              size_t* out_actual,
                              const fbl::RefPtr<dispatcher::ExecutionDomain>& domain,
                              dispatcher::Channel::ProcessHandler phandler,
                              dispatcher::Channel::ChannelClosedHandler chandler) {
    if (op != IHDA_IOCTL_GET_CHANNEL) {
        return ZX_ERR_NOT_SUPPORTED;
    }

    if ((out_buf == nullptr) ||
        (out_actual == nullptr) ||
        (out_len != sizeof(zx_handle_t))) {
        return ZX_ERR_INVALID_ARGS;
    }

    zx::channel remote_endpoint_out;
    zx_status_t res = CreateAndActivateChannel(domain,
                                               fbl::move(phandler),
                                               fbl::move(chandler),
                                               nullptr,
                                               &remote_endpoint_out);
    if (res == ZX_OK) {
        *(reinterpret_cast<zx_handle_t*>(out_buf)) = remote_endpoint_out.release();
        *out_actual = sizeof(zx_handle_t);
    }

    return res;
}

zx_status_t CreateAndActivateChannel(const fbl::RefPtr<dispatcher::ExecutionDomain>& domain,
                                     dispatcher::Channel::ProcessHandler phandler,
                                     dispatcher::Channel::ChannelClosedHandler chandler,
                                     fbl::RefPtr<dispatcher::Channel>* local_endpoint_out,
                                     zx::channel* remote_endpoint_out) {
    if (remote_endpoint_out == nullptr) {
        return ZX_ERR_INVALID_ARGS;
    }

    auto channel = dispatcher::Channel::Create();
    if (channel == nullptr) {
        return ZX_ERR_NO_MEMORY;
    }

    zx_status_t res = channel->Activate(remote_endpoint_out,
                                        domain,
                                        fbl::move(phandler),
                                        fbl::move(chandler));
    if ((res == ZX_OK) && (local_endpoint_out != nullptr)) {
        *local_endpoint_out = fbl::move(channel);
    }

    return res;
}

}  // namespace intel_hda
}  // namespace audio