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