/* * arch/ppc/kernel/prep_nvram.c * * 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; } }