Pull misc into release branch
[linux-2.6] / arch / powerpc / platforms / pseries / nvram.c
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
26 static unsigned int nvram_size;
27 static int nvram_fetch, nvram_store;
28 static char nvram_buf[NVRW_CNT];        /* assume this is in the first 4GB */
29 static DEFINE_SPINLOCK(nvram_lock);
30
31
32 static 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
76 static 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
118 static ssize_t pSeries_nvram_get_size(void)
119 {
120         return nvram_size ? nvram_size : -ENODEV;
121 }
122
123 int __init pSeries_nvram_init(void)
124 {
125         struct device_node *nvram;
126         const unsigned int *nbytes_p;
127         unsigned int proplen;
128
129         nvram = of_find_node_by_type(NULL, "nvram");
130         if (nvram == NULL)
131                 return -ENODEV;
132
133         nbytes_p = of_get_property(nvram, "#bytes", &proplen);
134         if (nbytes_p == NULL || proplen != sizeof(unsigned int))
135                 return -EIO;
136
137         nvram_size = *nbytes_p;
138
139         nvram_fetch = rtas_token("nvram-fetch");
140         nvram_store = rtas_token("nvram-store");
141         printk(KERN_INFO "PPC64 nvram contains %d bytes\n", nvram_size);
142         of_node_put(nvram);
143
144         ppc_md.nvram_read       = pSeries_nvram_read;
145         ppc_md.nvram_write      = pSeries_nvram_write;
146         ppc_md.nvram_size       = pSeries_nvram_get_size;
147
148         return 0;
149 }