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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 LT |
2 | /* |
3 | * ip22-nvram.c: NVRAM and serial EEPROM handling. | |
4 | * | |
5 | * Copyright (C) 2003 Ladislav Michl (ladis@linux-mips.org) | |
6 | */ | |
26dd3e4f | 7 | #include <linux/export.h> |
1da177e4 LT |
8 | |
9 | #include <asm/sgi/hpc3.h> | |
10 | #include <asm/sgi/ip22.h> | |
11 | ||
12 | /* Control opcode for serial eeprom */ | |
13 | #define EEPROM_READ 0xc000 /* serial memory read */ | |
14 | #define EEPROM_WEN 0x9800 /* write enable before prog modes */ | |
15 | #define EEPROM_WRITE 0xa000 /* serial memory write */ | |
16 | #define EEPROM_WRALL 0x8800 /* write all registers */ | |
17 | #define EEPROM_WDS 0x8000 /* disable all programming */ | |
70342287 RB |
18 | #define EEPROM_PRREAD 0xc000 /* read protect register */ |
19 | #define EEPROM_PREN 0x9800 /* enable protect register mode */ | |
20 | #define EEPROM_PRCLEAR 0xffff /* clear protect register */ | |
21 | #define EEPROM_PRWRITE 0xa000 /* write protect register */ | |
22 | #define EEPROM_PRDS 0x8000 /* disable protect register, forever */ | |
1da177e4 LT |
23 | |
24 | #define EEPROM_EPROT 0x01 /* Protect register enable */ | |
25 | #define EEPROM_CSEL 0x02 /* Chip select */ | |
26 | #define EEPROM_ECLK 0x04 /* EEPROM clock */ | |
27 | #define EEPROM_DATO 0x08 /* Data out */ | |
28 | #define EEPROM_DATI 0x10 /* Data in */ | |
29 | ||
30 | /* We need to use these functions early... */ | |
70342287 | 31 | #define delay() ({ \ |
1da177e4 LT |
32 | int x; \ |
33 | for (x=0; x<100000; x++) __asm__ __volatile__(""); }) | |
34 | ||
35 | #define eeprom_cs_on(ptr) ({ \ | |
5b3af8f1 TB |
36 | __raw_writel(__raw_readl(ptr) & ~EEPROM_DATO, ptr); \ |
37 | __raw_writel(__raw_readl(ptr) & ~EEPROM_ECLK, ptr); \ | |
38 | __raw_writel(__raw_readl(ptr) & ~EEPROM_EPROT, ptr); \ | |
70342287 | 39 | delay(); \ |
5b3af8f1 TB |
40 | __raw_writel(__raw_readl(ptr) | EEPROM_CSEL, ptr); \ |
41 | __raw_writel(__raw_readl(ptr) | EEPROM_ECLK, ptr); }) | |
1da177e4 | 42 | |
42a3b4f2 | 43 | |
1da177e4 | 44 | #define eeprom_cs_off(ptr) ({ \ |
5b3af8f1 TB |
45 | __raw_writel(__raw_readl(ptr) & ~EEPROM_ECLK, ptr); \ |
46 | __raw_writel(__raw_readl(ptr) & ~EEPROM_CSEL, ptr); \ | |
47 | __raw_writel(__raw_readl(ptr) | EEPROM_EPROT, ptr); \ | |
48 | __raw_writel(__raw_readl(ptr) | EEPROM_ECLK, ptr); }) | |
1da177e4 | 49 | |
70342287 | 50 | #define BITS_IN_COMMAND 11 |
1da177e4 LT |
51 | /* |
52 | * clock in the nvram command and the register number. For the | |
53 | * national semiconductor nv ram chip the op code is 3 bits and | |
42a3b4f2 | 54 | * the address is 6/8 bits. |
1da177e4 | 55 | */ |
78709b9d | 56 | static inline void eeprom_cmd(unsigned int *ctrl, unsigned cmd, unsigned reg) |
1da177e4 LT |
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 */ | |
5b3af8f1 | 64 | __raw_writel(__raw_readl(ctrl) | EEPROM_DATO, ctrl); |
1da177e4 | 65 | else |
5b3af8f1 TB |
66 | __raw_writel(__raw_readl(ctrl) & ~EEPROM_DATO, ctrl); |
67 | __raw_writel(__raw_readl(ctrl) & ~EEPROM_ECLK, ctrl); | |
68 | delay(); | |
69 | __raw_writel(__raw_readl(ctrl) | EEPROM_ECLK, ctrl); | |
70 | delay(); | |
1da177e4 LT |
71 | ser_cmd <<= 1; |
72 | } | |
78709b9d | 73 | /* see data sheet timing diagram */ |
5b3af8f1 | 74 | __raw_writel(__raw_readl(ctrl) & ~EEPROM_DATO, ctrl); |
1da177e4 LT |
75 | } |
76 | ||
78709b9d | 77 | unsigned short ip22_eeprom_read(unsigned int *ctrl, int reg) |
1da177e4 LT |
78 | { |
79 | unsigned short res = 0; | |
80 | int i; | |
81 | ||
5b3af8f1 | 82 | __raw_writel(__raw_readl(ctrl) & ~EEPROM_EPROT, ctrl); |
1da177e4 LT |
83 | eeprom_cs_on(ctrl); |
84 | eeprom_cmd(ctrl, EEPROM_READ, reg); | |
85 | ||
86 | /* clock the data ouf of serial mem */ | |
87 | for (i = 0; i < 16; i++) { | |
5b3af8f1 | 88 | __raw_writel(__raw_readl(ctrl) & ~EEPROM_ECLK, ctrl); |
1da177e4 | 89 | delay(); |
5b3af8f1 | 90 | __raw_writel(__raw_readl(ctrl) | EEPROM_ECLK, ctrl); |
1da177e4 LT |
91 | delay(); |
92 | res <<= 1; | |
5b3af8f1 | 93 | if (__raw_readl(ctrl) & EEPROM_DATI) |
1da177e4 LT |
94 | res |= 1; |
95 | } | |
42a3b4f2 | 96 | |
1da177e4 LT |
97 | eeprom_cs_off(ctrl); |
98 | ||
99 | return res; | |
100 | } | |
101 | ||
102 | EXPORT_SYMBOL(ip22_eeprom_read); | |
103 | ||
104 | /* | |
105 | * Read specified register from main NVRAM | |
106 | */ | |
107 | unsigned short ip22_nvram_read(int reg) | |
108 | { | |
109 | if (ip22_is_fullhouse()) | |
110 | /* IP22 (Indigo2 aka FullHouse) stores env variables into | |
111 | * 93CS56 Microwire Bus EEPROM 2048 Bit (128x16) */ | |
112 | return ip22_eeprom_read(&hpc3c0->eeprom, reg); | |
113 | else { | |
114 | unsigned short tmp; | |
115 | /* IP24 (Indy aka Guiness) uses DS1386 8K version */ | |
116 | reg <<= 1; | |
117 | tmp = hpc3c0->bbram[reg++] & 0xff; | |
118 | return (tmp << 8) | (hpc3c0->bbram[reg] & 0xff); | |
42a3b4f2 | 119 | } |
1da177e4 LT |
120 | } |
121 | ||
122 | EXPORT_SYMBOL(ip22_nvram_read); |