s3c6410_uart初始化及读写

参考：

1）《USER'S MANUAL-S3C6410X》第31章 UART

2）u-boot uart初始化及读写：u-boot-x.x.x/board/samsumg/smdk6410/lowlevel_init.S

　　　　　　　　　　　　 u-boot-x.x.x/cpu/s3c64xx/serial.c

3) 内核串口驱动：linux-x.x.x/driver/tty/serial/s3c6400.c samsung.c serial_core.c

代码：

uart.c

 #include "uart.h"

 #define GPACON        (*((volatile unsigned long *)0x7f008000))

 #define ULCON0        (*((volatile unsigned long *)0x7f005000))
 #define UCON0        (*((volatile unsigned long *)0x7f005004))
 #define UFCON0        (*((volatile unsigned long *)0x7f005008))
 #define UMCON0        (*((volatile unsigned long *)0x7f00500c))
 #define UTRSTAT0    (*((volatile unsigned long *)0x7f005010))
 #define UERSTAT0    (*((volatile unsigned long *)0x7f005014))
 #define UFSTAT0        (*((volatile unsigned long *)0x7f005018))
 #define UMSTAT0        (*((volatile unsigned long *)0x7f00501c))
 #define UTXH0        (*((volatile unsigned long *)0x7f005020))
 #define URXH0        (*((volatile unsigned long *)0x7f005024))
 #define UBRDIV0        (*((volatile unsigned long *)0x7f005028))
 #define UDIVSLOT0    (*((volatile unsigned long *)0x7f00502c))
 #define UINTP0        (*((volatile unsigned long *)0x7f005030))
 #define UINTSP0        (*((volatile unsigned long *)0x7f005034))
 #define UINTM0        (*((volatile unsigned long *)0x7f005038))

 void uart0_init(void)
 {
     GPACON &= ~0xff;
     GPACON |= 0X22;

     ULCON0 = 0x03; //data frame: 8n1
     /*
     clk: pclk
     tx int type: level
     rx int type: pulse
     rx err int enable
     tx/rx mode: interrupt or polling
     */
     UCON0 = 0x245;
     UFCON0 = 0x00; //disable fifo;
     UMCON0 = 0X00; //disable auto flow control(AFC)
     /*
     DIV_VAL = UBRDIV + (num of 1's in UDIVSLOT)/16
     DIV_VAL = (PCLK/(bps*16))-1 = (66000000/115200)-1=34.8
     UBRDIV = 34;
     num of 1's in UDIVSLOT = 13;
     */
     UBRDIV0 = 0x22;
     UDIVSLOT0 = 0x1fff;
 }

 int uart0_getc(void)
 {
     while (!(UTRSTAT0 & 0x1));
     return (URXH0 & 0xff);
 }

 void uart0_putc(const char c)
 {
     while (!(UTRSTAT0 & 0x2));
     UTXH0 = c;
     if (c == '\n')
     {
         uart0_putc('\r');
     }
 }

 void uart0_puts(const char *s)
 {
     while (*s)
     {
         uart0_putc(*s++);
     }
 }