serial_core.c

arm9的bootloader大家下载解压缩即可看到

#include "inc/serial.h"
#include "2410addr.h"
#define SERIAL_WRITE_READY()	((rUTRSTAT0) & (1<<2))
#define NULL 0 
unsigned char do_getc_with_timeout(unsigned long timeout, int*stat)
{
	unsigned char c;
	int rxstat;

	while (!(rUTRSTAT0 & (1<<0))) {
		if (--timeout == 0) break;
	}

	if (!timeout) {
		c = 0;
		*stat = -1;
	} else {
		c = rURXH0;
		*stat = rUERSTAT0&0xF;	
	}

	return (c);
}

int getc_errno = 0;
__u8 do_getc(vfuncp idler, unsigned long timeout, int *statp)
{
	__u8	c, rxstat;
	int	do_timeout = timeout != 0;

	getc_errno = 0;	/* reste errno */

	while(!(rUTRSTAT0 & (1<<0))) {

		if (do_timeout) {
			if (!timeout)
				break;
			timeout--;
		}

		if (idler)
			idler();
	}

	if (do_timeout && timeout == 0) {
		c = 0;
		rxstat = -1;
	} else {
		c = rURXH0;
		rxstat = rUERSTAT0&0xF;
	}

	if (rxstat) {
		getc_errno = rxstat;
		/*printk("RXSTAT error. status = 0x%08lx", rxstat);*/
		if (statp)
			*statp = rxstat;
	}
	return (c);
}

char getc(void)
{
	char c;
	unsigned long rxstat;

	while (!(rUTRSTAT0 & (1<<0))) /* nothing */;

	c = rURXH0;
	/* FIXME: 咯扁辑 俊矾 勤甸傅捞 鞘夸窃 */
	rxstat = rUERSTAT0&0xF;

	return c;
}

void putc(char c)
{   
    while (!SERIAL_WRITE_READY());
    rUTXH0=c;
}

/*
 * Reads and returns a character from the serial port
 *   - Times out after delay iterations checking for presence of character
 *   - Sets *error_p to UART error bits or - on timeout
 *   - On timeout, sets *error_p to -1 and returns 0
 */
char awaitkey(unsigned long delay, int* error_p)
{
	return (do_getc(NULL, delay, error_p));
}