cpc710_init_ram.c

Linux2.4.27在AT91RM9200下的U-BOOT代码。可以在Redhat9等版本下使用。适合ARM学习者使用。

/*
 * (C) Copyright 2002
 * Wolfgang Denk, DENX Software Engineering, [e-mail].
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * 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>
#include <common.h>
#include <asm/io.h>

#include "pcippc2.h"
#include "i2c.h"

typedef struct cpc710_mem_org_s
{
  u8		rows;
  u8		cols;
  u8		banks2;
  u8		org;
} cpc710_mem_org_t;

static int		cpc710_compute_mcer	(u32 *		mcer,
						 unsigned long *
								size,
						 unsigned int	sdram);
static int		cpc710_eeprom_checksum	(unsigned int	sdram);
static u8		cpc710_eeprom_read	(unsigned int	sdram,
						 unsigned int	offset);

static u32		cpc710_mcer_mem [] =
{
  0x000003f3,	/* 18 lines,    4 Mb */
  0x000003e3,	/* 19 lines,    8 Mb */
  0x000003c3,	/* 20 lines,   16 Mb */
  0x00000383,	/* 21 lines,   32 Mb */
  0x00000303,	/* 22 lines,   64 Mb */
  0x00000203,	/* 23 lines,  128 Mb */
  0x00000003,	/* 24 lines,  256 Mb */
  0x00000002,	/* 25 lines,  512 Mb */
  0x00000001	/* 26 lines, 1024 Mb */
};
static cpc710_mem_org_t	cpc710_mem_org [] =
{
  { 0x0c, 0x09, 0x02, 0x00 },	/* 0000: 12/ 9/2 */
  { 0x0d, 0x09, 0x02, 0x00 },	/* 0000: 13/ 9/2 */
  { 0x0d, 0x0a, 0x02, 0x00 },	/* 0000: 13/10/2 */
  { 0x0d, 0x0b, 0x02, 0x00 },	/* 0000: 13/11/2 */
  { 0x0d, 0x0c, 0x02, 0x00 },	/* 0000: 13/12/2 */
  { 0x0e, 0x0c, 0x02, 0x00 },	/* 0000: 14/12/2 */
  { 0x0b, 0x08, 0x02, 0x01 },	/* 0001: 11/ 8/2 */
  { 0x0b, 0x09, 0x01, 0x02 },	/* 0010: 11/ 9/1 */
  { 0x0b, 0x0a, 0x01, 0x03 },	/* 0011: 11/10/1 */
  { 0x0c, 0x08, 0x02, 0x04 },	/* 0100: 12/ 8/2 */
  { 0x0c, 0x0a, 0x02, 0x05 },	/* 0101: 12/10/2 */
  { 0x0d, 0x08, 0x01, 0x06 },	/* 0110: 13/ 8/1 */
  { 0x0d, 0x08, 0x02, 0x07 },	/* 0111: 13/ 8/2 */
  { 0x0d, 0x09, 0x01, 0x08 },	/* 1000: 13/ 9/1 */
  { 0x0d, 0x0a, 0x01, 0x09 },	/* 1001: 13/10/1 */
  { 0x0b, 0x08, 0x01, 0x0a },	/* 1010: 11/ 8/1 */
  { 0x0c, 0x08, 0x01, 0x0b },	/* 1011: 12/ 8/1 */
  { 0x0c, 0x09, 0x01, 0x0c },	/* 1100: 12/ 9/1 */
  { 0x0e, 0x09, 0x02, 0x0d },	/* 1101: 14/ 9/2 */
  { 0x0e, 0x0a, 0x02, 0x0e },	/* 1110: 14/10/2 */
  { 0x0e, 0x0b, 0x02, 0x0f } 	/* 1111: 14/11/2 */
};

unsigned long cpc710_ram_init (void)
{
  unsigned long 	memsize = 0;
  unsigned long		bank_size;
  u32			mcer;

#ifndef CFG_RAMBOOT
    /* Clear memory banks
     */
  out32(REG(SDRAM0, MCER0), 0);
  out32(REG(SDRAM0, MCER1), 0);
  out32(REG(SDRAM0, MCER2), 0);
  out32(REG(SDRAM0, MCER3), 0);
  out32(REG(SDRAM0, MCER4), 0);
  out32(REG(SDRAM0, MCER5), 0);
  out32(REG(SDRAM0, MCER6), 0);
  out32(REG(SDRAM0, MCER7), 0);
  iobarrier_rw();

    /* Disable memory
     */
  out32(REG(SDRAM0,MCCR), 0x13b06000);
  iobarrier_rw();
#endif

    /* Only the first memory bank is initialised now
     */
  if (! cpc710_compute_mcer(& mcer, & bank_size, 0))
  {
    puts("Unsupported SDRAM type !\n");
    hang();
  }
  memsize += bank_size;
#ifndef CFG_RAMBOOT
    /* Enable bank, zero start
     */
  out32(REG(SDRAM0, MCER0), mcer | 0x80000000);
  iobarrier_rw();
#endif

#ifndef CFG_RAMBOOT
    /* Enable memory
     */
  out32(REG(SDRAM0, MCCR), in32(REG(SDRAM0, MCCR)) | 0x80000000);

    /* Wait until initialisation finished
     */
  while (! (in32 (REG(SDRAM0, MCCR)) & 0x20000000))
  {
    iobarrier_rw();
  }

    /* Clear Memory Error Status and Address registers
     */
  out32(REG(SDRAM0, MESR), 0);
  out32(REG(SDRAM0, MEAR), 0);
  iobarrier_rw();

    /* ECC is not configured now
     */
#endif

    /* Memory size counter
     */
  out32(REG(CPC0, RGBAN1), memsize);

  return memsize;
}

static int cpc710_compute_mcer (
  u32 *			mcer,
  unsigned long	*	size,
  unsigned int		sdram)
{
  u8			rows;
  u8			cols;
  u8			banks2;
  unsigned int		lines;
  u32			mc = 0;
  unsigned int		i;
  cpc710_mem_org_t *	org = 0;


  if (! i2c_reset())
  {
    puts("Can't reset I2C!\n");
    hang();
  }

  if (! cpc710_eeprom_checksum(sdram))
  {
    puts("Invalid EEPROM checksum !\n");
    hang();
  }

  rows   = cpc710_eeprom_read(sdram, 3);
  cols   = cpc710_eeprom_read(sdram, 4);
    /* Can be 2 or 4 banks; divide by 2
     */
  banks2 = cpc710_eeprom_read(sdram, 17) / 2;

  lines = rows + cols + banks2;

  if (lines < 18 || lines > 26)
  {
      /* Unsupported configuration
       */
    return 0;
  }


  mc |= cpc710_mcer_mem [lines - 18] << 6;

  for (i = 0; i < sizeof(cpc710_mem_org) / sizeof(cpc710_mem_org_t); i++)
  {
    cpc710_mem_org_t *	corg = cpc710_mem_org + i;

    if (corg->rows == rows && corg->cols == cols && corg->banks2 == banks2)
    {
      org = corg;

      break;
    }
  }

  if (! org)
  {
      /* Unsupported configuration
       */
    return 0;
  }

  mc |= (u32) org->org << 2;

    /* Supported configuration
     */
  *mcer = mc;
  *size = 1l << (lines + 4);

  return 1;
}

static int cpc710_eeprom_checksum (
  unsigned int		sdram)
{
  u8			sum = 0;
  unsigned int		i;

  for (i = 0; i < 63; i++)
  {
    sum += cpc710_eeprom_read(sdram, i);
  }

  return sum == cpc710_eeprom_read(sdram, 63);
}

static u8 cpc710_eeprom_read (
  unsigned int		sdram,
  unsigned int		offset)
{
  u8			dev = (sdram << 1) | 0xa0;
  u8			data;

  if (! i2c_read_byte(& data, dev,offset))
  {
    puts("I2C error !\n");
    hang();
  }

  return data;
}