1/* 2 * Copyright (C) 1998 Corey Minyard 3 * 4 * This reads the NvRAM on PReP compliant machines (generally from IBM or 5 * Motorola). Motorola kept the format of NvRAM in their ROM, PPCBUG, the 6 * same, long after they had stopped producing PReP compliant machines. So 7 * this code is useful in those cases as well. 8 * 9 */ 10#include <linux/init.h> 11#include <linux/delay.h> 12#include <linux/slab.h> 13#include <linux/ioport.h> 14 15#include <asm/sections.h> 16#include <asm/io.h> 17#include <asm/machdep.h> 18#include <asm/prep_nvram.h> 19 20static char nvramData[MAX_PREP_NVRAM]; 21static NVRAM_MAP *nvram=(NVRAM_MAP *)&nvramData[0]; 22 23unsigned char prep_nvram_read_val(int addr) 24{ 25 outb(addr, PREP_NVRAM_AS0); 26 outb(addr>>8, PREP_NVRAM_AS1); 27 return inb(PREP_NVRAM_DATA); 28} 29 30void prep_nvram_write_val(int addr, 31 unsigned char val) 32{ 33 outb(addr, PREP_NVRAM_AS0); 34 outb(addr>>8, PREP_NVRAM_AS1); 35 outb(val, PREP_NVRAM_DATA); 36} 37 38void __init init_prep_nvram(void) 39{ 40 unsigned char *nvp; 41 int i; 42 int nvramSize; 43 44 /* 45 * The following could fail if the NvRAM were corrupt but 46 * we expect the boot firmware to have checked its checksum 47 * before boot 48 */ 49 nvp = (char *) &nvram->Header; 50 for (i=0; i<sizeof(HEADER); i++) 51 { 52 *nvp = ppc_md.nvram_read_val(i); 53 nvp++; 54 } 55 56 /* 57 * The PReP NvRAM may be any size so read in the header to 58 * determine how much we must read in order to get the complete 59 * GE area 60 */ 61 nvramSize=(int)nvram->Header.GEAddress+nvram->Header.GELength; 62 if(nvramSize>MAX_PREP_NVRAM) 63 { 64 /* 65 * NvRAM is too large 66 */ 67 nvram->Header.GELength=0; 68 return; 69 } 70 71 /* 72 * Read the remainder of the PReP NvRAM 73 */ 74 nvp = (char *) &nvram->GEArea[0]; 75 for (i=sizeof(HEADER); i<nvramSize; i++) 76 { 77 *nvp = ppc_md.nvram_read_val(i); 78 nvp++; 79 } 80} 81 82char *prep_nvram_get_var(const char *name) 83{ 84 char *cp; 85 int namelen; 86 87 namelen = strlen(name); 88 cp = prep_nvram_first_var(); 89 while (cp != NULL) { 90 if ((strncmp(name, cp, namelen) == 0) 91 && (cp[namelen] == '=')) 92 { 93 return cp+namelen+1; 94 } 95 cp = prep_nvram_next_var(cp); 96 } 97 98 return NULL; 99} 100 101char *prep_nvram_first_var(void) 102{ 103 if (nvram->Header.GELength == 0) { 104 return NULL; 105 } else { 106 return (((char *)nvram) 107 + ((unsigned int) nvram->Header.GEAddress)); 108 } 109} 110 111char *prep_nvram_next_var(char *name) 112{ 113 char *cp; 114 115 116 cp = name; 117 while (((cp - ((char *) nvram->GEArea)) < nvram->Header.GELength) 118 && (*cp != '\0')) 119 { 120 cp++; 121 } 122 123 /* Skip over any null characters. */ 124 while (((cp - ((char *) nvram->GEArea)) < nvram->Header.GELength) 125 && (*cp == '\0')) 126 { 127 cp++; 128 } 129 130 if ((cp - ((char *) nvram->GEArea)) < nvram->Header.GELength) { 131 return cp; 132 } else { 133 return NULL; 134 } 135} 136