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gerrit-public.fairphone.software / kernel / msm-4.9 / b3e5b5b2277f9c047082dcb309f665fe8b5706c1 / . / arch / powerpc / platforms / pseries / nvram.c
blob: 18abfb1f4e24852383671ddf6e82fd62ae784be4 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700[diff] [blame]1/*
2 * c 2001 PPC 64 Team, IBM Corp
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
8 *
9 * /dev/nvram driver for PPC64
10 *
11 * This perhaps should live in drivers/char
12 */
13
14
15#include <linux/types.h>
16#include <linux/errno.h>
17#include <linux/init.h>
18#include <linux/slab.h>
19#include <linux/spinlock.h>
20#include <asm/uaccess.h>
21#include <asm/nvram.h>
22#include <asm/rtas.h>
23#include <asm/prom.h>
24#include <asm/machdep.h>
25
26static unsigned int nvram_size;
27static int nvram_fetch, nvram_store;
28static char nvram_buf[NVRW_CNT]; /* assume this is in the first 4GB */
29static DEFINE_SPINLOCK(nvram_lock);
30
31
32static ssize_t pSeries_nvram_read(char *buf, size_t count, loff_t *index)
33{
34 unsigned int i;
35 unsigned long len;
36 int done;
37 unsigned long flags;
38 char *p = buf;
39
40
41 if (nvram_size == 0 || nvram_fetch == RTAS_UNKNOWN_SERVICE)
42 return -ENODEV;
43
44 if (*index >= nvram_size)
45 return 0;
46
47 i = *index;
48 if (i + count > nvram_size)
49 count = nvram_size - i;
50
51 spin_lock_irqsave(&nvram_lock, flags);
52
53 for (; count != 0; count -= len) {
54 len = count;
55 if (len > NVRW_CNT)
56 len = NVRW_CNT;
57
58 if ((rtas_call(nvram_fetch, 3, 2, &done, i, __pa(nvram_buf),
59 len) != 0) || len != done) {
60 spin_unlock_irqrestore(&nvram_lock, flags);
61 return -EIO;
62 }
63
64 memcpy(p, nvram_buf, len);
65
66 p += len;
67 i += len;
68 }
69
70 spin_unlock_irqrestore(&nvram_lock, flags);
71
72 *index = i;
73 return p - buf;
74}
75
76static ssize_t pSeries_nvram_write(char *buf, size_t count, loff_t *index)
77{
78 unsigned int i;
79 unsigned long len;
80 int done;
81 unsigned long flags;
82 const char *p = buf;
83
84 if (nvram_size == 0 || nvram_store == RTAS_UNKNOWN_SERVICE)
85 return -ENODEV;
86
87 if (*index >= nvram_size)
88 return 0;
89
90 i = *index;
91 if (i + count > nvram_size)
92 count = nvram_size - i;
93
94 spin_lock_irqsave(&nvram_lock, flags);
95
96 for (; count != 0; count -= len) {
97 len = count;
98 if (len > NVRW_CNT)
99 len = NVRW_CNT;
100
101 memcpy(nvram_buf, p, len);
102
103 if ((rtas_call(nvram_store, 3, 2, &done, i, __pa(nvram_buf),
104 len) != 0) || len != done) {
105 spin_unlock_irqrestore(&nvram_lock, flags);
106 return -EIO;
107 }
108
109 p += len;
110 i += len;
111 }
112 spin_unlock_irqrestore(&nvram_lock, flags);
113
114 *index = i;
115 return p - buf;
116}
117
118static ssize_t pSeries_nvram_get_size(void)
119{
120 return nvram_size ? nvram_size : -ENODEV;
121}
122
123int __init pSeries_nvram_init(void)
124{
125 struct device_node *nvram;
126 unsigned int *nbytes_p, proplen;
127
128 nvram = of_find_node_by_type(NULL, "nvram");
129 if (nvram == NULL)
130 return -ENODEV;
131
132 nbytes_p = (unsigned int *)get_property(nvram, "#bytes", &proplen);
133 if (nbytes_p == NULL || proplen != sizeof(unsigned int))
134 return -EIO;
135
136 nvram_size = *nbytes_p;
137
138 nvram_fetch = rtas_token("nvram-fetch");
139 nvram_store = rtas_token("nvram-store");
140 printk(KERN_INFO "PPC64 nvram contains %d bytes\n", nvram_size);
141 of_node_put(nvram);
142
143 ppc_md.nvram_read = pSeries_nvram_read;
144 ppc_md.nvram_write = pSeries_nvram_write;
145 ppc_md.nvram_size = pSeries_nvram_get_size;
146
147 return 0;
148}