/*
 * Copyright 2004-2008, Axel Dörfler, axeld@pinc-software.de.
 * Copyright 2013-2014, Fredrik Holmqvist, fredrik.holmqvist@gmail.com.
 * Copyright 2016, Jessica Hamilton, jessica.l.hamilton@gmail.com.
 * Distributed under the terms of the MIT License.
 */


#include "efi_platform.h"
#include <efi/protocol/serial-io.h>
#include "serial.h"

#include <boot/platform.h>
#include <arch/cpu.h>
#include <arch/generic/debug_uart.h>
#include <arch/generic/debug_uart_8250.h>
#include <boot/stage2.h>
#include <boot/stdio.h>

#include <string.h>


static efi_guid sSerialIOProtocolGUID = EFI_SERIAL_IO_PROTOCOL_GUID;
static const uint32 kSerialBaudRate = 115200;

static efi_serial_io_protocol *sEFISerialIO = NULL;
static bool sSerialEnabled = false;
static bool sEFIAvailable = true;


DebugUART* gUART = NULL;
bool gUARTSkipInit = false;


static void
serial_putc(char ch)
{
        if (!sSerialEnabled)
                return;

        // First we use EFI serial_io output if available
        if (sEFISerialIO != NULL) {
                size_t bufSize = 1;
                sEFISerialIO->Write(sEFISerialIO, &bufSize, &ch);
                return;
        }

#ifdef DEBUG
        // If we don't have EFI serial_io, fallback to EFI stdio
        if (sEFIAvailable) {
                char16_t ucsBuffer[2];
                ucsBuffer[0] = ch;
                ucsBuffer[1] = 0;
                kSystemTable->ConOut->OutputString(kSystemTable->ConOut, ucsBuffer);
                return;
        }
#endif

        // If EFI services are unavailable... try any UART
        // this can happen when serial_io is unavailable, or EFI
        // is exiting
        if (gUART != NULL) {
                if (gUART->PutChar(ch) < 0)
                        gUART = NULL;
                return;
        }
}


extern "C" void
serial_puts(const char* string, size_t size)
{
        if (!sSerialEnabled)
                return;

        while (size-- != 0) {
                char ch = string[0];

                if (ch == '\n') {
                        serial_putc('\r');
                        serial_putc('\n');
                } else if (ch != '\r')
                        serial_putc(ch);

                string++;
        }
}


extern "C" void
serial_disable(void)
{
        sSerialEnabled = false;
}


extern "C" void
serial_enable(void)
{
        sSerialEnabled = true;
        if ((gUART != NULL) && !gUARTSkipInit)
                gUART->InitPort(kSerialBaudRate);
}


extern "C" void
serial_init(void)
{
        if (sEFIAvailable) {
                // Check for EFI Serial
                efi_status status = kSystemTable->BootServices->LocateProtocol(
                        &sSerialIOProtocolGUID, NULL, (void**)&sEFISerialIO);

                if (status != EFI_SUCCESS)
                        sEFISerialIO = NULL;

                if (sEFISerialIO != NULL) {
                        // Setup serial, 0, 0 = Default Receive FIFO queue and default timeout
                        status = sEFISerialIO->SetAttributes(sEFISerialIO, kSerialBaudRate, 0, 0, NoParity, 8,
                                OneStopBit);

                        if (status != EFI_SUCCESS)
                                sEFISerialIO = NULL;

                        // serial_io was successful.
                        return;
                }
        }

#if defined(__i386__) || defined(__x86_64__)
        // On x86, we can try to setup COM1 as a gUART too
        // while this serial port may not physically exist,
        // the location is fixed on the x86 arch.
        // TODO: We could also try to pull from acpi?
        if (gUART == NULL) {
                gUART = arch_get_uart_8250(0x3f8, 1843200);

                // TODO: convert over to exclusively arch_args.uart?
                memset(gKernelArgs.platform_args.serial_base_ports, 0,
                        sizeof(uint16) * MAX_SERIAL_PORTS);
                gKernelArgs.platform_args.serial_base_ports[0] = 0x3f8;
        }
#endif

        if (gUART != NULL)
                gUART->InitEarly();
}


extern "C" void
serial_kernel_handoff(void)
{
        // The console was provided by boot services, disable it ASAP
        stdout = NULL;
        stderr = NULL;

        // Disconnect from EFI serial_io services is important as we leave the bootloader
        sEFISerialIO = NULL;
        sEFIAvailable = false;
}