// SPDX-License-Identifier: GPL-2.0
/*
 * 16550 serial console support.
 *
 * Original copied from <file:arch/ppc/boot/common/ns16550.c>
 * (which had no copyright)
 * Modifications: 2006 (c) MontaVista Software, Inc.
 *
 * Modified by: Mark A. Greer <mgreer@mvista.com>
 */
#include <stdarg.h>
#include <stddef.h>
#include "types.h"
#include "string.h"
#include "stdio.h"
#include "io.h"
#include "ops.h"
#include "of.h"

#define UART_DLL        0       /* Out: Divisor Latch Low */
#define UART_DLM        1       /* Out: Divisor Latch High */
#define UART_FCR        2       /* Out: FIFO Control Register */
#define UART_LCR        3       /* Out: Line Control Register */
#define UART_MCR        4       /* Out: Modem Control Register */
#define UART_LSR        5       /* In:  Line Status Register */
#define UART_LSR_THRE   0x20    /* Transmit-hold-register empty */
#define UART_LSR_DR     0x01    /* Receiver data ready */
#define UART_MSR        6       /* In:  Modem Status Register */
#define UART_SCR        7       /* I/O: Scratch Register */

static unsigned char *reg_base;
static u32 reg_shift;

static int ns16550_open(void)
{
        out_8(reg_base + (UART_FCR << reg_shift), 0x06);
        return 0;
}

static void ns16550_putc(unsigned char c)
{
        while ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_THRE) == 0);
        out_8(reg_base, c);
}

static unsigned char ns16550_getc(void)
{
        while ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_DR) == 0);
        return in_8(reg_base);
}

static u8 ns16550_tstc(void)
{
        return ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_DR) != 0);
}

int ns16550_console_init(void *devp, struct serial_console_data *scdp)
{
        int n;
        u32 reg_offset;

        if (dt_get_virtual_reg(devp, (void **)&reg_base, 1) < 1) {
                printf("virt reg parse fail...\r\n");
                return -1;
        }

        n = getprop(devp, "reg-offset", &reg_offset, sizeof(reg_offset));
        if (n == sizeof(reg_offset))
                reg_base += be32_to_cpu(reg_offset);

        n = getprop(devp, "reg-shift", &reg_shift, sizeof(reg_shift));
        if (n != sizeof(reg_shift))
                reg_shift = 0;
        else
                reg_shift = be32_to_cpu(reg_shift);

        scdp->open = ns16550_open;
        scdp->putc = ns16550_putc;
        scdp->getc = ns16550_getc;
        scdp->tstc = ns16550_tstc;
        scdp->close = NULL;

        return 0;
}