diff options
Diffstat (limited to 'arch/mips/sgi-ip22/ip22-nvram.c')
-rw-r--r-- | arch/mips/sgi-ip22/ip22-nvram.c | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/arch/mips/sgi-ip22/ip22-nvram.c b/arch/mips/sgi-ip22/ip22-nvram.c new file mode 100644 index 000000000000..de43e86fa17c --- /dev/null +++ b/arch/mips/sgi-ip22/ip22-nvram.c @@ -0,0 +1,119 @@ +/* + * 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) ({ \ + *ptr &= ~EEPROM_DATO; \ + *ptr &= ~EEPROM_ECLK; \ + *ptr &= ~EEPROM_EPROT; \ + delay(); \ + *ptr |= EEPROM_CSEL; \ + *ptr |= EEPROM_ECLK; }) + + +#define eeprom_cs_off(ptr) ({ \ + *ptr &= ~EEPROM_ECLK; \ + *ptr &= ~EEPROM_CSEL; \ + *ptr |= EEPROM_EPROT; \ + *ptr |= EEPROM_ECLK; }) + +#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(volatile 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 */ + *ctrl |= EEPROM_DATO; + else + *ctrl &= ~EEPROM_DATO; + *ctrl &= ~EEPROM_ECLK; + *ctrl |= EEPROM_ECLK; + ser_cmd <<= 1; + } + *ctrl &= ~EEPROM_DATO; /* see data sheet timing diagram */ +} + +unsigned short ip22_eeprom_read(volatile unsigned int *ctrl, int reg) +{ + unsigned short res = 0; + int i; + + *ctrl &= ~EEPROM_EPROT; + eeprom_cs_on(ctrl); + eeprom_cmd(ctrl, EEPROM_READ, reg); + + /* clock the data ouf of serial mem */ + for (i = 0; i < 16; i++) { + *ctrl &= ~EEPROM_ECLK; + delay(); + *ctrl |= EEPROM_ECLK; + delay(); + res <<= 1; + if (*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); |