/********************************************************************************************
 *        File:  serial.c
 *     Version:  1.0.0
 *   Copyright:  2013 (c) Guo Wenxue <guowenxue@gmail.com>
 * Description:  The UART on board drivers/functions.
 *   ChangeLog:  1, Release initial version on "Mon Feb 25 22:58:49 CST 2013"
 *
 *******************************************************************************************/

#include "s3c6410.h"

/*
 * Initialise the serial port with the given baudrate. The settings
 * are always 8 data bits, no parity, 1 stop bit, no start bits.
 */
int serial_init(int baudrate)
{
    unsigned int     regv;

    s3c64xx_uart *const uart = s3c64xx_get_base_uart(S3C64XX_UART0);

    /* UART I/O port initialize: GPA0->RXD0, GPA1->TXD0) */
    regv = s3c_readl(GPACON);
    regv = (regv & ~(0xff<<0)) | (0x22<<0);	
    s3c_writel(regv, GPACON);

    /* RXD0: Pull-down, TXD0: pull up/down disable */
    regv = s3c_readl(GPAPUD);
    regv = (regv & ~(0xf<<0)) | (0x1<<0);	
    s3c_writel(regv, GPAPUD);

    /* Normal Mode, No Parity, 1 Stop Bit, 8 Bit Data */
    uart->ULCON = 3;

    /* PCLK divide, Polling Mode */
    uart->UCON = (0x2<<10) | (1<<9) | (1<<8) | (1<<2) | (1<<0);
    uart->UFCON = 0;  /* Disable FIFO */
    uart->UMCON = 0;  /* Disable Auto Flow Control */

    /* Baudrate, DIV=PCLK/(bps*16)-1=66000000/(115200*16)-1 = 34; */
    s3c_writel(34, UBRDIV0);

    for (regv=0; regv<0x100; regv++)  ;

    uart->UDIVSLOT = 0x80;

	return 0;
}

/*
 * Read a single byte from the serial port. Returns 1 on success, 0
 * otherwise. When the function is succesfull, the character read is
 * written into its argument c.
 */
int serial_getc(void)
{
    s3c64xx_uart *const uart = s3c64xx_get_base_uart(S3C64XX_UART0);

    /* wait for character to arrive */
    while (!(uart->UTRSTAT & 0x1)) ; 

    return uart->URXH & 0xff;
}

/*
 * Output a single byte to the serial port.
 */
void serial_putc(const char c)
{
    s3c64xx_uart *const uart = s3c64xx_get_base_uart(S3C64XX_UART0);

    /*  wait for room in the tx FIFO */
    while (!(uart->UTRSTAT & 0x2));
            
    uart->UTXH = c;
    if (c == '\n') serial_putc('\r');   /*  If \n, also do \r */
}

/*
 * Test whether a character is in the RX buffer
 */
int serial_tstc(void)
{
    s3c64xx_uart *const uart = s3c64xx_get_base_uart(S3C64XX_UART0); 
    return uart->UTRSTAT & 0x1;
}


void serial_puts(const char *s)
{
    while (*s)
        serial_putc(*s++);
}