Release 4.14 arch/mips/sgi-ip22/ip22-nvram.c

// SPDX-License-Identifier: GPL-2.0
/*
 * ip22-nvram.c: NVRAM and serial EEPROM handling.
 *
 * Copyright (C) 2003 Ladislav Michl (ladis@linux-mips.org)
 */
#include <linux/export.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);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ralf Bächle
124
88.57%
2
66.67%
Thomas Bogendoerfer
16
11.43%
1
33.33%
Total
140
100.00%
3
100.00%



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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ralf Bächle
115
94.26%
2
66.67%
Thomas Bogendoerfer
7
5.74%
1
33.33%
Total
122
100.00%
3
100.00%


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);
	}
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ralf Bächle
68
100.00%
1
100.00%
Total
68
100.00%
1
100.00%


EXPORT_SYMBOL(ip22_nvram_read);
Overall Contributors
Person
Tokens
Prop
Commits
CommitProp
Ralf Bächle
415
91.61%
5
55.56%
Thomas Bogendoerfer
24
5.30%
1
11.11%
Andrew Morton
12
2.65%
1
11.11%
Greg Kroah-Hartman
1
0.22%
1
11.11%
Paul Gortmaker
1
0.22%
1
11.11%
Total
453
100.00%
9
100.00%
Directory: arch/mips/sgi-ip22

Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.