s3c2410.c

SMDK2440 boot code, base on vivi

/*  
 *  drivers/serial/serial_s3c2410.c: 
 *    specfic routines for S3C2410 UARTs
 *
 *  Author:	Janghoon Lyu
 *  Created:	October 16, 2003
 *  Copyright:	MIZI Research, Inc. All rights reserved.
 *
 *  Last modified: $Date: 2004/05/24 06:11:35 $ 
 *                 $Revision: 1.4 $
 *
 *  2003-10-22  Add timeout to prevent system halt. 
 *              By Janghoon Lyu.
 */

#include <config.h>
#include <machine.h>

#define ULCON_OFS	(0x00)	/* R/W, UART line control register */
#define UCON_OFS	(0x04)	/* R/W, UART control register */
#define UFCON_OFS	(0x08)	/* R/W, UART FIFO control register */
#define UMCON_OFS	(0x0C)	/* R/W, UART modem control register */
#define UTRSTAT_OFS	(0x10)	/* R  , UART Tx/Rx status register */
#define UERSTAT_OFS	(0x14)	/* R  , UART Rx error status register */
#define UFSTAT_OFS	(0x18)	/* R  , UART FIFO status register */
#define UMSTAT_OFS	(0x1C)	/* R  , UART Modem status register */
#define UTXHL_OFS	(0x20)	/*   W, UART transmit(little-end) buffer */
#define UTXHB_OFS	(0x23)	/*   W, UART transmit(big-end) buffer */
#define URXHL_OFS	(0x24)	/* R  , UART receive(little-end) buffer */
#define URXHB_OFS	(0x27)	/* R  , UART receive(big-end) buffer */
#define UBRDIV_OFS	(0x28)	/* R/W, Baud rate divisor register */

#if defined(CONFIG_SERIAL_UART0)
#define OFFSET		0x0
#define GPIO_OFFSET	2
#elif defined(CONFIG_SERIAL_UART1)
#define OFFSET		0x4000
#define GPIO_OFFSET	4
#elif defined(CONFIG_SERIAL_UART2)
#define OFFSET		0x8000
#define GPIO_OFFSET	6
#else
#error Not exist UART on this processor.
#endif

void
uart_init(void)
{
	unsigned long base_addr = 0x50000000 + OFFSET;
	unsigned long baudrate = CONFIG_SERIAL_DEFAULT_BAUDRATE;
	unsigned long ubrdiv = ((UART_REF_CLK / (baudrate * 16)) - 1);
	unsigned long timeout;

	/* set GPIOs */
	GPHCON &= ~(0xf << GPIO_OFFSET);
	GPHCON |= (0xa << GPIO_OFFSET);
	GPHUP |= (0x3 << GPIO_OFFSET);

	/* set UART controller */
	*(volatile unsigned long *)(base_addr+UFCON_OFS) = 0x0;
	*(volatile unsigned long *)(base_addr+UMCON_OFS) = 0x0;
	*(volatile unsigned long *)(base_addr+ULCON_OFS) = 0x3;
	*(volatile unsigned long *)(base_addr+UCON_OFS) = 0x45;
	*(volatile unsigned long *)(base_addr+UBRDIV_OFS) = ubrdiv;

	/* flush FIFO of UART */
	timeout = 10000;
	while (1) {
		char c;
		unsigned long stat;

		stat = *(volatile unsigned long *)(base_addr+UTRSTAT_OFS);
		if ((stat & (1 << 2)) && (stat & (1 << 1)))
			break;

		c = *(volatile unsigned char *)(base_addr+UTXHL_OFS);

		/* Anyway, I will go. */
		if (--timeout < 0) break;
	}
}