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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/mips/sgi-ip22/ip22-nvram.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/mips/sgi-ip22/ip22-nvram.c')
-rw-r--r--arch/mips/sgi-ip22/ip22-nvram.c119
1 files changed, 119 insertions, 0 deletions
diff --git a/arch/mips/sgi-ip22/ip22-nvram.c b/arch/mips/sgi-ip22/ip22-nvram.c
new file mode 100644
index 000000000000..de43e86fa17c
--- /dev/null
+++ b/arch/mips/sgi-ip22/ip22-nvram.c
@@ -0,0 +1,119 @@
1/*
2 * ip22-nvram.c: NVRAM and serial EEPROM handling.
3 *
4 * Copyright (C) 2003 Ladislav Michl (ladis@linux-mips.org)
5 */
6#include <linux/module.h>
7
8#include <asm/sgi/hpc3.h>
9#include <asm/sgi/ip22.h>
10
11/* Control opcode for serial eeprom */
12#define EEPROM_READ 0xc000 /* serial memory read */
13#define EEPROM_WEN 0x9800 /* write enable before prog modes */
14#define EEPROM_WRITE 0xa000 /* serial memory write */
15#define EEPROM_WRALL 0x8800 /* write all registers */
16#define EEPROM_WDS 0x8000 /* disable all programming */
17#define EEPROM_PRREAD 0xc000 /* read protect register */
18#define EEPROM_PREN 0x9800 /* enable protect register mode */
19#define EEPROM_PRCLEAR 0xffff /* clear protect register */
20#define EEPROM_PRWRITE 0xa000 /* write protect register */
21#define EEPROM_PRDS 0x8000 /* disable protect register, forever */
22
23#define EEPROM_EPROT 0x01 /* Protect register enable */
24#define EEPROM_CSEL 0x02 /* Chip select */
25#define EEPROM_ECLK 0x04 /* EEPROM clock */
26#define EEPROM_DATO 0x08 /* Data out */
27#define EEPROM_DATI 0x10 /* Data in */
28
29/* We need to use these functions early... */
30#define delay() ({ \
31 int x; \
32 for (x=0; x<100000; x++) __asm__ __volatile__(""); })
33
34#define eeprom_cs_on(ptr) ({ \
35 *ptr &= ~EEPROM_DATO; \
36 *ptr &= ~EEPROM_ECLK; \
37 *ptr &= ~EEPROM_EPROT; \
38 delay(); \
39 *ptr |= EEPROM_CSEL; \
40 *ptr |= EEPROM_ECLK; })
41
42
43#define eeprom_cs_off(ptr) ({ \
44 *ptr &= ~EEPROM_ECLK; \
45 *ptr &= ~EEPROM_CSEL; \
46 *ptr |= EEPROM_EPROT; \
47 *ptr |= EEPROM_ECLK; })
48
49#define BITS_IN_COMMAND 11
50/*
51 * clock in the nvram command and the register number. For the
52 * national semiconductor nv ram chip the op code is 3 bits and
53 * the address is 6/8 bits.
54 */
55static inline void eeprom_cmd(volatile unsigned int *ctrl, unsigned cmd,
56 unsigned reg)
57{
58 unsigned short ser_cmd;
59 int i;
60
61 ser_cmd = cmd | (reg << (16 - BITS_IN_COMMAND));
62 for (i = 0; i < BITS_IN_COMMAND; i++) {
63 if (ser_cmd & (1<<15)) /* if high order bit set */
64 *ctrl |= EEPROM_DATO;
65 else
66 *ctrl &= ~EEPROM_DATO;
67 *ctrl &= ~EEPROM_ECLK;
68 *ctrl |= EEPROM_ECLK;
69 ser_cmd <<= 1;
70 }
71 *ctrl &= ~EEPROM_DATO; /* see data sheet timing diagram */
72}
73
74unsigned short ip22_eeprom_read(volatile unsigned int *ctrl, int reg)
75{
76 unsigned short res = 0;
77 int i;
78
79 *ctrl &= ~EEPROM_EPROT;
80 eeprom_cs_on(ctrl);
81 eeprom_cmd(ctrl, EEPROM_READ, reg);
82
83 /* clock the data ouf of serial mem */
84 for (i = 0; i < 16; i++) {
85 *ctrl &= ~EEPROM_ECLK;
86 delay();
87 *ctrl |= EEPROM_ECLK;
88 delay();
89 res <<= 1;
90 if (*ctrl & EEPROM_DATI)
91 res |= 1;
92 }
93
94 eeprom_cs_off(ctrl);
95
96 return res;
97}
98
99EXPORT_SYMBOL(ip22_eeprom_read);
100
101/*
102 * Read specified register from main NVRAM
103 */
104unsigned short ip22_nvram_read(int reg)
105{
106 if (ip22_is_fullhouse())
107 /* IP22 (Indigo2 aka FullHouse) stores env variables into
108 * 93CS56 Microwire Bus EEPROM 2048 Bit (128x16) */
109 return ip22_eeprom_read(&hpc3c0->eeprom, reg);
110 else {
111 unsigned short tmp;
112 /* IP24 (Indy aka Guiness) uses DS1386 8K version */
113 reg <<= 1;
114 tmp = hpc3c0->bbram[reg++] & 0xff;
115 return (tmp << 8) | (hpc3c0->bbram[reg] & 0xff);
116 }
117}
118
119EXPORT_SYMBOL(ip22_nvram_read);