Logo Search packages:      
Sourcecode: linux version File versions

ip22-nvram.c

/*
 * ip22-nvram.c: NVRAM and serial EEPROM handling.
 *
 * Copyright (C) 2003 Ladislav Michl (ladis@linux-mips.org)
 */
#include <linux/module.h>

#include <asm/sgi/hpc3.h>
#include <asm/sgi/ip22.h>

/* Control opcode for serial eeprom  */
#define EEPROM_READ     0xc000      /* serial memory read */
#define EEPROM_WEN      0x9800      /* write enable before prog modes */
#define EEPROM_WRITE    0xa000      /* serial memory write */
#define EEPROM_WRALL    0x8800      /* write all registers */
#define EEPROM_WDS      0x8000      /* disable all programming */
#define     EEPROM_PRREAD     0xc000      /* read protect register */
#define     EEPROM_PREN 0x9800      /* enable protect register mode */
#define     EEPROM_PRCLEAR    0xffff      /* clear protect register */
#define     EEPROM_PRWRITE    0xa000      /* write protect register */
#define     EEPROM_PRDS 0x8000      /* disable protect register, forever */

#define EEPROM_EPROT    0x01  /* Protect register enable */
#define EEPROM_CSEL     0x02  /* Chip select */
#define EEPROM_ECLK     0x04  /* EEPROM clock */
#define EEPROM_DATO     0x08  /* Data out */
#define EEPROM_DATI     0x10  /* Data in */

/* We need to use these functions early... */
#define delay()   ({                                  \
      int x;                                          \
      for (x=0; x<100000; x++) __asm__ __volatile__(""); })

#define eeprom_cs_on(ptr) ({  \
      __raw_writel(__raw_readl(ptr) & ~EEPROM_DATO, ptr);   \
      __raw_writel(__raw_readl(ptr) & ~EEPROM_ECLK, ptr);   \
      __raw_writel(__raw_readl(ptr) & ~EEPROM_EPROT, ptr);  \
      delay();                                          \
      __raw_writel(__raw_readl(ptr) | EEPROM_CSEL, ptr);    \
      __raw_writel(__raw_readl(ptr) | EEPROM_ECLK, ptr); })


#define eeprom_cs_off(ptr) ({ \
      __raw_writel(__raw_readl(ptr) & ~EEPROM_ECLK, ptr);   \
      __raw_writel(__raw_readl(ptr) & ~EEPROM_CSEL, ptr);   \
      __raw_writel(__raw_readl(ptr) | EEPROM_EPROT, ptr);   \
      __raw_writel(__raw_readl(ptr) | EEPROM_ECLK, ptr); })

#define     BITS_IN_COMMAND   11
/*
 * clock in the nvram command and the register number. For the
 * national semiconductor nv ram chip the op code is 3 bits and
 * the address is 6/8 bits.
 */
static inline void eeprom_cmd(unsigned int *ctrl, unsigned cmd, unsigned reg)
{
      unsigned short ser_cmd;
      int i;

      ser_cmd = cmd | (reg << (16 - BITS_IN_COMMAND));
      for (i = 0; i < BITS_IN_COMMAND; i++) {
            if (ser_cmd & (1<<15))  /* if high order bit set */
                  __raw_writel(__raw_readl(ctrl) | EEPROM_DATO, ctrl);
            else
                  __raw_writel(__raw_readl(ctrl) & ~EEPROM_DATO, ctrl);
            __raw_writel(__raw_readl(ctrl) & ~EEPROM_ECLK, ctrl);
            delay();
            __raw_writel(__raw_readl(ctrl) | EEPROM_ECLK, ctrl);
            delay();
            ser_cmd <<= 1;
      }
      /* see data sheet timing diagram */
      __raw_writel(__raw_readl(ctrl) & ~EEPROM_DATO, ctrl);
}

unsigned short ip22_eeprom_read(unsigned int *ctrl, int reg)
{
      unsigned short res = 0;
      int i;

      __raw_writel(__raw_readl(ctrl) & ~EEPROM_EPROT, ctrl);
      eeprom_cs_on(ctrl);
      eeprom_cmd(ctrl, EEPROM_READ, reg);

      /* clock the data ouf of serial mem */
      for (i = 0; i < 16; i++) {
            __raw_writel(__raw_readl(ctrl) & ~EEPROM_ECLK, ctrl);
            delay();
            __raw_writel(__raw_readl(ctrl) | EEPROM_ECLK, ctrl);
            delay();
            res <<= 1;
            if (__raw_readl(ctrl) & EEPROM_DATI)
                  res |= 1;
      }

      eeprom_cs_off(ctrl);

      return res;
}

EXPORT_SYMBOL(ip22_eeprom_read);

/*
 * Read specified register from main NVRAM
 */
unsigned short ip22_nvram_read(int reg)
{
      if (ip22_is_fullhouse())
            /* IP22 (Indigo2 aka FullHouse) stores env variables into
             * 93CS56 Microwire Bus EEPROM 2048 Bit (128x16) */
            return ip22_eeprom_read(&hpc3c0->eeprom, reg);
      else {
            unsigned short tmp;
            /* IP24 (Indy aka Guiness) uses DS1386 8K version */
            reg <<= 1;
            tmp = hpc3c0->bbram[reg++] & 0xff;
            return (tmp << 8) | (hpc3c0->bbram[reg] & 0xff);
      }
}

EXPORT_SYMBOL(ip22_nvram_read);

Generated by  Doxygen 1.6.0   Back to index