serial.c

来自「国产CPU－龙芯（loongson)BIOS源代码」· C语言 代码 · 共 53 行

#include <types.h>

#define FCR_COM1_BASE 0x1f004090
#define FCR_COM1_DATA  (FCR_COM1_BASE + 0x0)
#define FCR_COM1_FCR   (FCR_COM1_BASE + 0x2)
#define FCR_COM1_LSR   (FCR_COM1_BASE + 0x5)

#define UART_SET(idx, value) KSEG1_STORE8(FCR_COM1_BASE + idx, value)
#define UART_GET(idx) KSEG1_LOAD8(FCR_COM1_BASE + idx)

static u8 init = 0;
void init_serial()
{
    UART_SET(0x3, 0x80); /* LCR, set DLAB = 1 */
    UART_SET(0x0, 0x6c); /* Crystal:16.6MHz, Baudrate = 9600bps ->0x6C  */
    UART_SET(0x1, 0x00); /* Baudrate=9600. MSB should be 0 */
    UART_SET(0x3, 0x0b); /* 8N1 */
    UART_SET(0x2, 0x47); /* RCVR Trigger & FIFO Enable */
}

void serial_putc(u8 c)
{
	u32 counter = 0x1000;
	if (!init)
	{
		init_serial();
		init = 1;
	}
	while ((counter--) && !(UART_GET(0x5) & 0x20));
	if (counter)
		UART_SET(0x0,c);
}

void serial_puts(u8 *buf)
{
	u8 *p = NULL;
	for (p = buf; *p != 0; p++)
		serial_putc(*p);
}

void serial_put32(u32 value)
{
	 char buf[11];
	 buf[0] = '0';
	 buf[1] = 'x';
	 ctx(buf + 2, (value >> 24) & 0xff);
	 ctx(buf + 4, (value >> 16) & 0xff);
	 ctx(buf + 6, (value >> 8) & 0xff);
	 ctx(buf + 8, value & 0xff);
	 buf[10] = 0;
	 serial_puts(buf);
}