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/arch/ppc/syslib/prep_nvram.c

https://bitbucket.org/evzijst/gittest
C | 141 lines | 96 code | 17 blank | 28 comment | 20 complexity | e387b101f862ac0eb78cb69b79efb667 MD5 | raw file
  1/*
  2 * arch/ppc/kernel/prep_nvram.c
  3 *
  4 * Copyright (C) 1998  Corey Minyard
  5 *
  6 * This reads the NvRAM on PReP compliant machines (generally from IBM or
  7 * Motorola).  Motorola kept the format of NvRAM in their ROM, PPCBUG, the
  8 * same, long after they had stopped producing PReP compliant machines.  So
  9 * this code is useful in those cases as well.
 10 *
 11 */
 12#include <linux/init.h>
 13#include <linux/delay.h>
 14#include <linux/slab.h>
 15#include <linux/ioport.h>
 16
 17#include <asm/sections.h>
 18#include <asm/segment.h>
 19#include <asm/io.h>
 20#include <asm/machdep.h>
 21#include <asm/prep_nvram.h>
 22
 23static char nvramData[MAX_PREP_NVRAM];
 24static NVRAM_MAP *nvram=(NVRAM_MAP *)&nvramData[0];
 25
 26unsigned char __prep prep_nvram_read_val(int addr)
 27{
 28	outb(addr, PREP_NVRAM_AS0);
 29	outb(addr>>8, PREP_NVRAM_AS1);
 30	return inb(PREP_NVRAM_DATA);
 31}
 32
 33void __prep prep_nvram_write_val(int           addr,
 34			  unsigned char val)
 35{
 36	outb(addr, PREP_NVRAM_AS0);
 37	outb(addr>>8, PREP_NVRAM_AS1);
 38   	outb(val, PREP_NVRAM_DATA);
 39}
 40
 41void __init init_prep_nvram(void)
 42{
 43	unsigned char *nvp;
 44	int  i;
 45	int  nvramSize;
 46
 47	/*
 48	 * The following could fail if the NvRAM were corrupt but
 49	 * we expect the boot firmware to have checked its checksum
 50	 * before boot
 51	 */
 52	nvp = (char *) &nvram->Header;
 53	for (i=0; i<sizeof(HEADER); i++)
 54	{
 55		*nvp = ppc_md.nvram_read_val(i);
 56		nvp++;
 57	}
 58
 59	/*
 60	 * The PReP NvRAM may be any size so read in the header to
 61	 * determine how much we must read in order to get the complete
 62	 * GE area
 63	 */
 64	nvramSize=(int)nvram->Header.GEAddress+nvram->Header.GELength;
 65	if(nvramSize>MAX_PREP_NVRAM)
 66	{
 67		/*
 68		 * NvRAM is too large
 69		 */
 70		nvram->Header.GELength=0;
 71		return;
 72	}
 73
 74	/*
 75	 * Read the remainder of the PReP NvRAM
 76	 */
 77	nvp = (char *) &nvram->GEArea[0];
 78	for (i=sizeof(HEADER); i<nvramSize; i++)
 79	{
 80		*nvp = ppc_md.nvram_read_val(i);
 81		nvp++;
 82	}
 83}
 84
 85__prep
 86char __prep *prep_nvram_get_var(const char *name)
 87{
 88	char *cp;
 89	int  namelen;
 90
 91	namelen = strlen(name);
 92	cp = prep_nvram_first_var();
 93	while (cp != NULL) {
 94		if ((strncmp(name, cp, namelen) == 0)
 95		    && (cp[namelen] == '='))
 96		{
 97			return cp+namelen+1;
 98		}
 99		cp = prep_nvram_next_var(cp);
100	}
101
102	return NULL;
103}
104
105__prep
106char __prep *prep_nvram_first_var(void)
107{
108        if (nvram->Header.GELength == 0) {
109		return NULL;
110	} else {
111		return (((char *)nvram)
112			+ ((unsigned int) nvram->Header.GEAddress));
113	}
114}
115
116__prep
117char __prep *prep_nvram_next_var(char *name)
118{
119	char *cp;
120
121
122	cp = name;
123	while (((cp - ((char *) nvram->GEArea)) < nvram->Header.GELength)
124	       && (*cp != '\0'))
125	{
126		cp++;
127	}
128
129	/* Skip over any null characters. */
130	while (((cp - ((char *) nvram->GEArea)) < nvram->Header.GELength)
131	       && (*cp == '\0'))
132	{
133		cp++;
134	}
135
136	if ((cp - ((char *) nvram->GEArea)) < nvram->Header.GELength) {
137		return cp;
138	} else {
139		return NULL;
140	}
141}