uart.c

开发板外设接口实验（1～7）

/*
 *	uart.c   -  uart api & driver 
 *	
 *	Author: 	li ming <[e-mail]>
 *	Date:		2008-4-16
 *	Copyleft:	http://www.lumit.org
 */
 
#include "uart.h"
#include "led.h"
#include "irq.h"

/* define the relative gpio register */
#define SYSCFG      0x03FF0000
#define UART0_BASE	(SYSCFG + 0xD000)
#define UART1_BASE 	(SYSCFG + 0xE000)

#define UART0_ULCON		(*((volatile unsigned *)(UART0_BASE+0x00)))
#define UART0_UCON		(*((volatile unsigned *)(UART0_BASE+0x04)))

/* Line control register bits */
#define	ULCON	0x00
#define	UCON	0x04
#define	USTAT	0x08
#define	UTXBUF	0x0C
#define	URXBUF	0x10
#define	UBRDIV	0x14

/* UART Control Register bits */
#define	ULCR8bits	(3)
#define	ULCRS1StopBit	(0)
#define	ULCRNoParity	(0)

/* UART Status Register bits */
#define USROverrun     	(1 << 0)
#define	USRParity      	(1 << 1)
#define	USRFraming     	(1 << 2)
#define	USRBreak       	(1 << 3)
#define	USRDTR		(1 << 4)
#define	USRRxData      	(1 << 5) 
#define	USRTxHoldEmpty 	(1 << 6)
#define	USRTxEmpty     	(1 << 7)

/* default baud rate value */
#define BAUD_9600	(162 << 4)
#define BAUD_19200	(80 << 4)
#define BAUD_38400	(40 << 4)
#define BAUD_57600	(26 << 4)
#define BAUD_115200	(13 << 4)

/* UART primitives */
#define GET_STATUS(p)	(*(volatile unsigned  *)((p) + USTAT))
#define RX_DATA(s)     	((s) & USRRxData)
#define GET_CHAR(p)	(*(volatile unsigned  *)((p) + URXBUF))
#define TX_READY(s)    	((s) & USRTxHoldEmpty)
#define PUT_CHAR(p,c)  	(*(unsigned  *)((p) + UTXBUF) = (unsigned )(c))

/* ************************************************************************ */
int uart0_init(void)
{
	//PUT_CHAR(UART0_BASE, 0x0);		
	
	/* Set port for 8 bit, one stop, no parity  */
	*(volatile unsigned *)(UART0_BASE + ULCON) = ULCR8bits;
	 
	*(volatile unsigned *)(UART0_BASE + UBRDIV) = BAUD_19200;
		
	return 0;
}
 
static void (*uart0_irq_hooker)(void) = 0;
static char recv_buff[1024];
static char send_buff[1024];
static int recv_data_offset = 0;
static int recv_getchar_offset = 0;
static int send_data_offset = 0;
static int send_putchar_offset = 0;

int uart0_putchar(char ch)
{		
#if 0
	/* read tx ready flag, when =1 break */
	while ( TX_READY(GET_STATUS(UART0_BASE))==0)
		;
	PUT_CHAR(UART0_BASE, ch);
	return 0;
#endif
	
	/* append ch to buff */
	send_buff[send_putchar_offset++] = ch;

	/* enable tx interrupt */	
	PUT_CHAR(UART0_BASE, 0x0);	
	*(volatile unsigned *)(UART0_BASE + UCON) |= (0x1 << 3);
	
	return 0;
}

char uart0_getchar(void)
{		
#if 0 
	char ch;
	
	while ( (RX_DATA(GET_STATUS(UART0_BASE)))==0 )
		;
	ch = GET_CHAR(UART0_BASE);
	return ch;
#endif	
	
	if( recv_getchar_offset < recv_data_offset )
		return recv_buff[recv_getchar_offset++];
	
	return 0;
}

void uart0_install_irq_hooker( void (*hooker)(void) )
{
	uart0_irq_hooker = hooker;
}

void uart0_recv_irq_handler(void)
{	
	/* recv the tdata */
	recv_buff[recv_data_offset++] = GET_CHAR(UART0_BASE);
	
	led_on(2);
	led_off(2);
	return;
}

void uart0_send_irq_handler(void)
{	
	if( send_data_offset < send_putchar_offset )
		PUT_CHAR(UART0_BASE, send_buff[send_data_offset++]);		
					
	led_on(3);
	led_off(3);
	return ;
}

int uart0_enable_recv_irq(void)
{
	/* register irq no.5 to a handler */
	request_irq(5, uart0_recv_irq_handler);	

	/* set rx mode as interrupt */
	*(volatile unsigned *)(UART0_BASE + UCON) |= 0x01;

	/* enable rx interrupt */
	*(volatile unsigned *)(UART0_BASE + UCON) |= 0x04;		
	
	return 0;
}

int uart0_enable_send_irq(void)
{
	/* register irq no.4 to a handler */	
	request_irq(4, uart0_send_irq_handler);	

	/* enable tx interrupt */
	*(volatile unsigned *)(UART0_BASE + UCON) |= (0x1 << 3);

	return 0;
}

int uart0_test(void)
{
	char ch;
	
	uart0_init();
	
	while(1)
	{
		ch = uart0_getchar();
		if( ch == '\r' )	// 0x0d
		{				
				//uart0_putchar('\r');
				uart0_putchar('\n');
				//continue;
		}
		if( ch == '\b' )	// 0x08
		{
				uart0_putchar('\b');		
				uart0_putchar(' ');
				//uart0_putchar('\b');
				//continue;
		}
		if( ch != 0 )
			uart0_putchar(ch);
	}	
}
/* ************************************************************************ */