openwrt-xburst/package/uboot-xburst/files/cpu/mips/jz_serial.c

/*
 * Jz47xx UART support
 *
 * Hardcoded to UART 0 for now
 * Options also hardcoded to 8N1
 *
 *  Copyright (c) 2005
 *  Ingenic Semiconductor, <jlwei@ingenic.cn>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */

#include <config.h>

#if defined(CONFIG_JZ4740)

#include <common.h>

#include <asm/jz4740.h>

#undef UART_BASE
#ifndef CONFIG_SYS_UART_BASE
#define UART_BASE  UART0_BASE
#else
#define UART_BASE  CONFIG_SYS_UART_BASE
#endif

/******************************************************************************
*
* serial_init - initialize a channel
*
* This routine initializes the number of data bits, parity
* and set the selected baud rate. Interrupts are disabled.
* Set the modem control signals if the option is selected.
*
* RETURNS: N/A
*/

int serial_init (void)
{
#if !defined(CONFIG_NAND_U_BOOT) || defined(CONFIG_NAND_SPL)
	volatile u8 *uart_fcr = (volatile u8 *)(UART_BASE + OFF_FCR);
	volatile u8 *uart_lcr = (volatile u8 *)(UART_BASE + OFF_LCR);
	volatile u8 *uart_ier = (volatile u8 *)(UART_BASE + OFF_IER);
	volatile u8 *uart_sircr = (volatile u8 *)(UART_BASE + OFF_SIRCR);

	/* Disable port interrupts while changing hardware */
	*uart_ier = 0;

	/* Disable UART unit function */
	*uart_fcr = ~UART_FCR_UUE;

	/* Set both receiver and transmitter in UART mode (not SIR) */
	*uart_sircr = ~(SIRCR_RSIRE | SIRCR_TSIRE);

	/* Set databits, stopbits and parity. (8-bit data, 1 stopbit, no parity) */
	*uart_lcr = UART_LCR_WLEN_8 | UART_LCR_STOP_1;

	/* Set baud rate */
	serial_setbrg();

	/* Enable UART unit, enable and clear FIFO */
	*uart_fcr = UART_FCR_UUE | UART_FCR_FE | UART_FCR_TFLS | UART_FCR_RFLS;
#endif
	return 0;
}

void serial_setbrg (void)
{
	volatile u8 *uart_lcr = (volatile u8 *)(UART_BASE + OFF_LCR);
	volatile u8 *uart_dlhr = (volatile u8 *)(UART_BASE + OFF_DLHR);
	volatile u8 *uart_dllr = (volatile u8 *)(UART_BASE + OFF_DLLR);
	u32 baud_div, tmp;

	baud_div = CONFIG_SYS_EXTAL / 16 / CONFIG_BAUDRATE;

	tmp = *uart_lcr;
	tmp |= UART_LCR_DLAB;
	*uart_lcr = tmp;

	*uart_dlhr = (baud_div >> 8) & 0xff;
	*uart_dllr = baud_div & 0xff;

	tmp &= ~UART_LCR_DLAB;
	*uart_lcr = tmp;
}

void serial_putc (const char c)
{
	volatile u8 *uart_lsr = (volatile u8 *)(UART_BASE + OFF_LSR);
	volatile u8 *uart_tdr = (volatile u8 *)(UART_BASE + OFF_TDR);

	if (c == '\n') serial_putc ('\r');

	/* Wait for fifo to shift out some bytes */
	while ( !((*uart_lsr & (UART_LSR_TDRQ | UART_LSR_TEMT)) == 0x60) );

	*uart_tdr = (u8)c;
}

void serial_puts (const char *s)
{
	while (*s) {
		serial_putc (*s++);
	}
}

int serial_getc (void)
{
	volatile u8 *uart_rdr = (volatile u8 *)(UART_BASE + OFF_RDR);

	while (!serial_tstc());

	return *uart_rdr;
}

int serial_tstc (void)
{
	volatile u8 *uart_lsr = (volatile u8 *)(UART_BASE + OFF_LSR);

	if (*uart_lsr & UART_LSR_DR) {
		/* Data in rfifo */
		return (1);
	}
	return 0;
}

#endif