serial_sh.c

uboot详细解读可用启动引导LINUX2.6内核

/*
 * SuperH SCIF device driver.
 * Copyright (c) 2007,2008 Nobuhiro Iwamatsu
 *
 * 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 <common.h>
#include <asm/processor.h>

#ifdef CFG_SCIF_CONSOLE

#if defined (CONFIG_CONS_SCIF0)
#define SCIF_BASE	SCIF0_BASE
#elif defined (CONFIG_CONS_SCIF1)
#define SCIF_BASE	SCIF1_BASE
#elif defined (CONFIG_CONS_SCIF2)
#define SCIF_BASE	SCIF2_BASE
#else
#error "Default SCIF doesn't set....."
#endif

/* Base register */
#define SCSMR	(vu_short *)(SCIF_BASE + 0x0)
#define SCBRR	(vu_char  *)(SCIF_BASE + 0x4)
#define SCSCR	(vu_short *)(SCIF_BASE + 0x8)
#define SCFCR	(vu_short *)(SCIF_BASE + 0x18)
#define SCFDR	(vu_short *)(SCIF_BASE + 0x1C)
#ifdef CONFIG_CPU_SH7720	/* SH7720 specific */
# define SCFSR	(vu_short *)(SCIF_BASE + 0x14)	/* SCSSR */
# define SCFTDR	(vu_char  *)(SCIF_BASE + 0x20)
# define SCFRDR	(vu_char  *)(SCIF_BASE + 0x24)
#else
# define SCFTDR (vu_char  *)(SCIF_BASE + 0xC)
# define SCFSR 	(vu_short *)(SCIF_BASE + 0x10)
# define SCFRDR (vu_char  *)(SCIF_BASE + 0x14)
#endif

#if	defined(CONFIG_CPU_SH7780) || \
	defined(CONFIG_CPU_SH7785)
# define SCRFDR	(vu_short *)(SCIF_BASE + 0x20)
# define SCSPTR	(vu_short *)(SCIF_BASE + 0x24)
# define SCLSR	(vu_short *)(SCIF_BASE + 0x28)
# define SCRER	(vu_short *)(SCIF_BASE + 0x2C)
# define LSR_ORER	1
# define FIFOLEVEL_MASK	0xFF
#elif defined(CONFIG_CPU_SH7763)
# if defined (CONFIG_CONS_SCIF2)
# define SCSPTR	(vu_short *)(SCIF_BASE + 0x20)
# define SCLSR 	(vu_short *)(SCIF_BASE + 0x24)
# define LSR_ORER	1
# define FIFOLEVEL_MASK	0x1F
# else
# define SCRFDR	(vu_short *)(SCIF_BASE + 0x20)
# define SCSPTR	(vu_short *)(SCIF_BASE + 0x24)
# define SCLSR	(vu_short *)(SCIF_BASE + 0x28)
# define SCRER	(vu_short *)(SCIF_BASE + 0x2C)
# define LSR_ORER	1
# define FIFOLEVEL_MASK	0xFF
# endif
#elif defined(CONFIG_CPU_SH7750) || \
	defined(CONFIG_CPU_SH7751) || \
	defined(CONFIG_CPU_SH7722)
# define SCSPTR	(vu_short *)(SCIF_BASE + 0x20)
# define SCLSR 	(vu_short *)(SCIF_BASE + 0x24)
# define LSR_ORER	1
# define FIFOLEVEL_MASK	0x1F
#elif defined(CONFIG_CPU_SH7720)
# define SCLSR		(vu_short *)(SCIF_BASE + 0x24)
# define LSR_ORER	0x0200
# define FIFOLEVEL_MASK	0x1F
#elif defined(CONFIG_CPU_SH7710) || \
	defined(CONFIG_CPU_SH7712)
# define SCLSR	SCFSR		/* SCSSR */
# define LSR_ORER	1
# define FIFOLEVEL_MASK	0x1F
#endif

/* SCBRR register value setting */
#if defined(CONFIG_CPU_SH7720)
# define SCBRR_VALUE(bps, clk) (((clk*2)+16*bps)/(32*bps)-1)
#else /* Generic SuperH */
# define SCBRR_VALUE(bps, clk) ((clk+16*bps)/(32*bps)-1)
#endif

#define SCR_RE 		(1 << 4)
#define SCR_TE 		(1 << 5)
#define FCR_RFRST	(1 << 1)	/* RFCL */
#define FCR_TFRST	(1 << 2)	/* TFCL */
#define FSR_DR   	(1 << 0)
#define FSR_RDF  	(1 << 1)
#define FSR_FER  	(1 << 3)
#define FSR_BRK  	(1 << 4)
#define FSR_FER  	(1 << 3)
#define FSR_TEND 	(1 << 6)
#define FSR_ER   	(1 << 7)

/*----------------------------------------------------------------------*/

void serial_setbrg(void)
{
	DECLARE_GLOBAL_DATA_PTR;
	*SCBRR = SCBRR_VALUE(gd->baudrate, CONFIG_SYS_CLK_FREQ);
}

int serial_init(void)
{
	*SCSCR = (SCR_RE | SCR_TE);
	*SCSMR = 0;
	*SCSMR = 0;
	*SCFCR = (FCR_RFRST | FCR_TFRST);
	*SCFCR;
	*SCFCR = 0;

	serial_setbrg();
	return 0;
}

static int serial_rx_fifo_level(void)
{
#if defined(SCRFDR)
	return (*SCRFDR >> 0) & FIFOLEVEL_MASK;
#else
	return (*SCFDR >> 0) & FIFOLEVEL_MASK;
#endif
}

void serial_raw_putc(const char c)
{
	unsigned int fsr_bits_to_clear;

	while (1) {
		if (*SCFSR & FSR_TEND) {	/* Tx fifo is empty */
			fsr_bits_to_clear = FSR_TEND;
			break;
		}
	}

	*SCFTDR = c;
	if (fsr_bits_to_clear != 0)
		*SCFSR &= ~fsr_bits_to_clear;
}

void serial_putc(const char c)
{
	if (c == '\n')
		serial_raw_putc('\r');
	serial_raw_putc(c);
}

void serial_puts(const char *s)
{
	char c;
	while ((c = *s++) != 0)
		serial_putc(c);
}

int serial_tstc(void)
{
	return serial_rx_fifo_level()? 1 : 0;
}

#define FSR_ERR_CLEAR   0x0063
#define RDRF_CLEAR      0x00fc
void handle_error(void)
{

	(void)*SCFSR;
	*SCFSR = FSR_ERR_CLEAR;
	(void)*SCLSR;
	*SCLSR = 0x00;
}

int serial_getc_check(void)
{
	unsigned short status;

	status = *SCFSR;

	if (status & (FSR_FER | FSR_ER | FSR_BRK))
		handle_error();
	if (*SCLSR & LSR_ORER)
		handle_error();
	return (status & (FSR_DR | FSR_RDF));
}

int serial_getc(void)
{
	unsigned short status;
	char ch;
	while (!serial_getc_check()) ;

	ch = *SCFRDR;
	status = *SCFSR;

	*SCFSR = RDRF_CLEAR;

	if (status & (FSR_FER | FSR_FER | FSR_ER | FSR_BRK))
		handle_error();

	if (*SCLSR & LSR_ORER)
		handle_error();

	return ch;
}

#endif /* CFG_SCIF_CONSOLE */