122 lines
3.6 KiB
C
122 lines
3.6 KiB
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);
|