// 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.

#include "uart16550.h"

#include <ddk/protocol/serial.h>
#include <lib/fake_ddk/fake_ddk.h>
#include <lib/mock-function/mock-function.h>
#include <lib/zx/event.h>
#include <zxtest/zxtest.h>

namespace {

class Uart16550Harness : public zxtest::Test {
public:
    void SetUp() override {
        zx::interrupt interrupt;
        ASSERT_OK(zx::interrupt::create({}, 0, ZX_INTERRUPT_VIRTUAL, &interrupt));
        ASSERT_OK(zx::event::create(0, &callback_finished_));

        write_
            .ExpectCall(0b1000'0000, 3)  // divisor latch enable
            .ExpectCall(0b1110'0111, 2)  // fifo control reset
            .ExpectCall(0b0000'0000, 3)  // divisor latch disable
            .ExpectCall(0b1000'0000, 3)  // divisor latch enable
            .ExpectCall(0b0000'0001, 0)  // lower
            .ExpectCall(0b0000'0000, 1)  // upper
            .ExpectCall(0b0000'0011, 3)  // 8N1
            .ExpectCall(0b0000'1011, 4)  // no flow control
            .ExpectCall(0b1000'0000, 3)  // divisor latch enable
            .ExpectCall(0b1110'0111, 2)  // fifo control reset
            .ExpectCall(0b0000'0000, 3)  // divisor latch disable
            .ExpectCall(0b0000'1101, 1); // enable interrupts

        read_.ExpectCall(0b1110'0000, 2) // interrupt identify
            .ExpectCall(0b0000'0000, 3); // line control

        auto read_call = [&](uint16_t port) { return read_.Call(port); };

        auto write_call = [&](uint8_t data, uint16_t port) { write_.Call(data, port); };

        device_ = std::make_unique<uart16550::Uart16550>();
        ASSERT_OK(device_->Init(std::move(interrupt), read_call, write_call));
        ASSERT_EQ(device_->FifoDepth(), 64);
        ASSERT_FALSE(device_->Enabled());
        ASSERT_FALSE(device_->NotifyCallbackSet());

        serial_notify_t notify = {
            .callback = [](void*, serial_state_t) { ASSERT_TRUE(false); },
            .ctx = nullptr,
        };

        ASSERT_OK(device_->SerialImplSetNotifyCallback(&notify));
        ASSERT_FALSE(device_->Enabled());
        ASSERT_TRUE(device_->NotifyCallbackSet());

        ASSERT_OK(device_->SerialImplEnable(true));
        ASSERT_TRUE(device_->Enabled());
        ASSERT_TRUE(device_->NotifyCallbackSet());

        read_.VerifyAndClear();
        write_.VerifyAndClear();
    }

    void TearDown() override {
        if (device_->Enabled()) {
            write_
                .ExpectCall(0b0000'0000, 1); // disable interrupts
        } else {
            write_.ExpectNoCall();
        }
        read_.ExpectNoCall();

        uart16550::Uart16550* device = device_.release();
        device->DdkRelease();

        read_.VerifyAndClear();
        write_.VerifyAndClear();
        callback_finished_.reset();
    }

    uart16550::Uart16550& Device() {
        return *device_;
    }

    void InterruptDriver() {
        ASSERT_OK(Device().InterruptHandle()->trigger(0, zx::time()));
    }

    void SignalCallbackFinished() {
        ASSERT_OK(callback_finished_.signal(ZX_EVENT_SIGNAL_MASK, ZX_EVENT_SIGNALED));
    }

    void WaitCallbackFinished() {
        ASSERT_OK(callback_finished_.wait_one(ZX_EVENT_SIGNALED, zx::time::infinite(), nullptr));
    }

    mock_function::MockFunction<uint8_t, uint16_t>& ReadMock() {
        return read_;
    }

    mock_function::MockFunction<void, uint8_t, uint16_t>& WriteMock() {
        return write_;
    }

private:
    std::unique_ptr<uart16550::Uart16550> device_;
    mock_function::MockFunction<uint8_t, uint16_t> read_;
    mock_function::MockFunction<void, uint8_t, uint16_t> write_;
    zx::event callback_finished_;
};

TEST_F(Uart16550Harness, SerialImplGetInfo) {
    WriteMock().ExpectNoCall();
    ReadMock().ExpectNoCall();

    serial_port_info_t info;
    ASSERT_OK(Device().SerialImplGetInfo(&info));

    WriteMock().VerifyAndClear();
    ReadMock().VerifyAndClear();
}

TEST_F(Uart16550Harness, SerialImplConfig) {
    WriteMock()
        .ExpectCall(0b0000'0000, 1)  // disable interrupts
        .ExpectCall(0b1000'0000, 3)  // enable divisor latch
        .ExpectCall(0b1000'0000, 0)  // lower
        .ExpectCall(0b0001'0110, 1)  // upper
        .ExpectCall(0b0001'1101, 3)  // 6E2
        .ExpectCall(0b0010'1000, 4)  // automatic flow control
        .ExpectCall(0b1001'1101, 3)  // enable divisor latch
        .ExpectCall(0b0100'0000, 0)  // lower
        .ExpectCall(0b0000'1011, 1)  // upper
        .ExpectCall(0b0001'1101, 3); // disable divisor latch

    ReadMock()
        .ExpectCall(0b0000'0000, 3)  // line control
        .ExpectCall(0b0001'1101, 3); // line control

    ASSERT_OK(Device().SerialImplEnable(false));

    static constexpr uint32_t serial_test_config = SERIAL_DATA_BITS_6 | SERIAL_STOP_BITS_2 |
                                                   SERIAL_PARITY_EVEN | SERIAL_FLOW_CTRL_CTS_RTS;
    ASSERT_OK(Device().SerialImplConfig(20, serial_test_config));
    ASSERT_OK(Device().SerialImplConfig(40, SERIAL_SET_BAUD_RATE_ONLY));

    ASSERT_NOT_OK(Device().SerialImplConfig(0, serial_test_config));
    ASSERT_NOT_OK(Device().SerialImplConfig(UINT32_MAX, serial_test_config));
    ASSERT_NOT_OK(Device().SerialImplConfig(1, serial_test_config));

    WriteMock().VerifyAndClear();
    ReadMock().VerifyAndClear();
}

TEST_F(Uart16550Harness, SerialImplEnable) {
    WriteMock()
        .ExpectCall(0b0000'0000, 1)  // disable interrupts
        .ExpectCall(0b1000'0000, 3)  // divisor latch enable
        .ExpectCall(0b1110'0111, 2)  // fifo control reset
        .ExpectCall(0b0000'0000, 3)  // divisor latch disable
        .ExpectCall(0b0000'1101, 1); // enable interrupts

    ReadMock()
        .ExpectNoCall();

    ASSERT_OK(Device().SerialImplEnable(false));
    ASSERT_FALSE(Device().Enabled());
    ASSERT_TRUE(Device().NotifyCallbackSet());

    ASSERT_OK(Device().SerialImplEnable(false));
    ASSERT_FALSE(Device().Enabled());
    ASSERT_TRUE(Device().NotifyCallbackSet());

    ASSERT_OK(Device().SerialImplEnable(true));
    ASSERT_TRUE(Device().Enabled());
    ASSERT_TRUE(Device().NotifyCallbackSet());

    WriteMock().VerifyAndClear();
    ReadMock().VerifyAndClear();
}

TEST_F(Uart16550Harness, SerialImplSetNotifyCallback) {
    WriteMock()
        .ExpectCall(0b0000'0000, 1); // disable interrupts
    ReadMock()
        .ExpectNoCall();

    serial_notify_t notify = {
        .callback = [](void*, serial_state_t) { ASSERT_TRUE(false); },
        .ctx = nullptr,
    };

    ASSERT_NOT_OK(Device().SerialImplSetNotifyCallback(&notify));
    ASSERT_TRUE(Device().Enabled());
    ASSERT_TRUE(Device().NotifyCallbackSet());

    ASSERT_OK(Device().SerialImplEnable(false));
    ASSERT_OK(Device().SerialImplSetNotifyCallback(&notify));
    ASSERT_TRUE(Device().NotifyCallbackSet());

    ASSERT_OK(Device().SerialImplSetNotifyCallback(nullptr));
    ASSERT_FALSE(Device().NotifyCallbackSet());

    ASSERT_OK(Device().SerialImplSetNotifyCallback(&notify));
    ASSERT_TRUE(Device().NotifyCallbackSet());

    notify.callback = nullptr;

    ASSERT_TRUE(Device().NotifyCallbackSet());

    ASSERT_OK(Device().SerialImplSetNotifyCallback(&notify));
    ASSERT_FALSE(Device().NotifyCallbackSet());

    WriteMock().VerifyAndClear();
    ReadMock().VerifyAndClear();
}

TEST_F(Uart16550Harness, SerialImplRead) {
    auto readable = [](void* ctx, serial_state_t state) {
        auto* harness = static_cast<Uart16550Harness*>(ctx);
        ASSERT_TRUE(state & SERIAL_STATE_READABLE);
        harness->SignalCallbackFinished();
    };

    serial_notify_t notify = {
        .callback = readable,
        .ctx = this,
    };

    WriteMock()
        .ExpectCall(0b0000'0000, 1)  // disable interrupts
        .ExpectCall(0b1000'0000, 3)  // divisor latch enable
        .ExpectCall(0b1110'0111, 2)  // fifo control reset
        .ExpectCall(0b0000'0000, 3)  // divisor latch disable
        .ExpectCall(0b0000'1101, 1); // enable interrupts

    ReadMock()
        .ExpectCall(0b0000'0000, 5)  // data not ready
        .ExpectCall(0b0000'0100, 2)  // rx available interrupt id
        .ExpectCall(0b0000'0001, 5)  // data ready
        .ExpectCall(0b0000'0001, 5)  // data ready
        .ExpectCall(0x0F, 0)         // buffer[0]
        .ExpectCall(0b0000'0001, 5)  // data ready
        .ExpectCall(0xF0, 0)         // buffer[1]
        .ExpectCall(0b0000'0001, 5)  // data ready
        .ExpectCall(0x59, 0)         // buffer[2]
        .ExpectCall(0b0000'0000, 5); // data ready

    ASSERT_OK(Device().SerialImplEnable(false));
    ASSERT_OK(Device().SerialImplSetNotifyCallback(&notify));

    uint8_t unreadable_buffer[1] = {0};
    size_t actual;

    ASSERT_EQ(Device().SerialImplRead(unreadable_buffer, sizeof(unreadable_buffer), &actual),
              ZX_ERR_BAD_STATE);
    ASSERT_EQ(actual, 0);

    ASSERT_OK(Device().SerialImplEnable(true));

    ASSERT_EQ(Device().SerialImplRead(unreadable_buffer, sizeof(unreadable_buffer), &actual),
              ZX_ERR_SHOULD_WAIT);
    ASSERT_EQ(actual, 0);

    InterruptDriver();
    WaitCallbackFinished();

    uint8_t readable_buffer[4] = {0xDE, 0xAD, 0xBE, 0xEF};
    uint8_t expect_buffer[4] = {0x0F, 0xF0, 0x59, 0xEF};

    ASSERT_OK(Device().SerialImplRead(readable_buffer, sizeof(readable_buffer), &actual));
    ASSERT_EQ(actual, 3);
    ASSERT_BYTES_EQ(readable_buffer, expect_buffer, sizeof(readable_buffer));

    WriteMock().VerifyAndClear();
    ReadMock().VerifyAndClear();
}

TEST_F(Uart16550Harness, SerialImplWrite) {
    auto writable = [](void* ctx, serial_state_t state) {
        auto* harness = static_cast<Uart16550Harness*>(ctx);
        ASSERT_TRUE(state & SERIAL_STATE_WRITABLE);
        harness->SignalCallbackFinished();
    };

    serial_notify_t notify = {
        .callback = writable,
        .ctx = this,
    };

    WriteMock()
        .ExpectCall(0b0000'0000, 1) // disable interrupts
        .ExpectCall(0b1000'0000, 3) // divisor latch enable
        .ExpectCall(0b1110'0111, 2) // fifo control reset
        .ExpectCall(0b0000'0000, 3) // divisor latch disable
        .ExpectCall(0b0000'1101, 1) // enable interrupts
        .ExpectCall(0b0000'1111, 1) // write interrupts
        .ExpectCall(0b0000'1101, 1) // write interrupts
        .ExpectCall(0xDE, 0)        // writable_buffer[0]
        .ExpectCall(0xAD, 0)        // writable_buffer[1]
        .ExpectCall(0xBE, 0)        // writable_buffer[2]
        .ExpectCall(0xEF, 0);       // writable_buffer[3]

    ReadMock()
        .ExpectCall(0b0000'0000, 5)  // tx empty
        .ExpectCall(0b0000'1101, 1)  // read interrupts
        .ExpectCall(0b0000'0010, 2)  // tx empty interrupt id
        .ExpectCall(0b0000'1111, 1)  // read interrupts
        .ExpectCall(0b0100'0000, 5); // tx empty

    ASSERT_OK(Device().SerialImplEnable(false));
    ASSERT_OK(Device().SerialImplSetNotifyCallback(&notify));

    uint8_t unwritable_buffer[1] = {0};
    size_t actual;

    ASSERT_EQ(Device().SerialImplWrite(unwritable_buffer, sizeof(unwritable_buffer), &actual),
              ZX_ERR_BAD_STATE);
    ASSERT_EQ(actual, 0);

    ASSERT_OK(Device().SerialImplEnable(true));

    ASSERT_EQ(Device().SerialImplWrite(unwritable_buffer, sizeof(unwritable_buffer), &actual),
              ZX_ERR_SHOULD_WAIT);
    ASSERT_EQ(actual, 0);

    InterruptDriver();
    WaitCallbackFinished();

    uint8_t writable_buffer[4] = {0xDE, 0xAD, 0xBE, 0xEF};

    ASSERT_OK(Device().SerialImplWrite(writable_buffer, sizeof(writable_buffer), &actual));
    ASSERT_EQ(actual, 4);

    WriteMock().VerifyAndClear();
    ReadMock().VerifyAndClear();
}

} // namespace