prep_nvram.c
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/*
* Copyright (C) 1998 Corey Minyard
*
* This reads the NvRAM on PReP compliant machines (generally from IBM or
* Motorola). Motorola kept the format of NvRAM in their ROM, PPCBUG, the
* same, long after they had stopped producing PReP compliant machines. So
* this code is useful in those cases as well.
*
*/
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/ioport.h>
#include <asm/sections.h>
#include <asm/io.h>
#include <asm/machdep.h>
#include <asm/prep_nvram.h>
static char nvramData[MAX_PREP_NVRAM];
static NVRAM_MAP *nvram=(NVRAM_MAP *)&nvramData[0];
unsigned char prep_nvram_read_val(int addr)
{
outb(addr, PREP_NVRAM_AS0);
outb(addr>>8, PREP_NVRAM_AS1);
return inb(PREP_NVRAM_DATA);
}
void prep_nvram_write_val(int addr,
unsigned char val)
{
outb(addr, PREP_NVRAM_AS0);
outb(addr>>8, PREP_NVRAM_AS1);
outb(val, PREP_NVRAM_DATA);
}
void __init init_prep_nvram(void)
{
unsigned char *nvp;
int i;
int nvramSize;
/*
* The following could fail if the NvRAM were corrupt but
* we expect the boot firmware to have checked its checksum
* before boot
*/
nvp = (char *) &nvram->Header;
for (i=0; i<sizeof(HEADER); i++)
{
*nvp = ppc_md.nvram_read_val(i);
nvp++;
}
/*
* The PReP NvRAM may be any size so read in the header to
* determine how much we must read in order to get the complete
* GE area
*/
nvramSize=(int)nvram->Header.GEAddress+nvram->Header.GELength;
if(nvramSize>MAX_PREP_NVRAM)
{
/*
* NvRAM is too large
*/
nvram->Header.GELength=0;
return;
}
/*
* Read the remainder of the PReP NvRAM
*/
nvp = (char *) &nvram->GEArea[0];
for (i=sizeof(HEADER); i<nvramSize; i++)
{
*nvp = ppc_md.nvram_read_val(i);
nvp++;
}
}
char *prep_nvram_get_var(const char *name)
{
char *cp;
int namelen;
namelen = strlen(name);
cp = prep_nvram_first_var();
while (cp != NULL) {
if ((strncmp(name, cp, namelen) == 0)
&& (cp[namelen] == '='))
{
return cp+namelen+1;
}
cp = prep_nvram_next_var(cp);
}
return NULL;
}
char *prep_nvram_first_var(void)
{
if (nvram->Header.GELength == 0) {
return NULL;
} else {
return (((char *)nvram)
+ ((unsigned int) nvram->Header.GEAddress));
}
}
char *prep_nvram_next_var(char *name)
{
char *cp;
cp = name;
while (((cp - ((char *) nvram->GEArea)) < nvram->Header.GELength)
&& (*cp != '\0'))
{
cp++;
}
/* Skip over any null characters. */
while (((cp - ((char *) nvram->GEArea)) < nvram->Header.GELength)
&& (*cp == '\0'))
{
cp++;
}
if ((cp - ((char *) nvram->GEArea)) < nvram->Header.GELength) {
return cp;
} else {
return NULL;
}
}