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
pSeries_nvram_read(char * buf,size_t count,loff_t * index)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
pSeries_nvram_write(char * buf,size_t count,loff_t * index)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
pSeries_nvram_get_size(void)118 static ssize_t pSeries_nvram_get_size(void)
119 {
120 return nvram_size ? nvram_size : -ENODEV;
121 }
122
pSeries_nvram_init(void)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 of_node_put(nvram);
136 return -EIO;
137 }
138
139 nvram_size = *nbytes_p;
140
141 nvram_fetch = rtas_token("nvram-fetch");
142 nvram_store = rtas_token("nvram-store");
143 printk(KERN_INFO "PPC64 nvram contains %d bytes\n", nvram_size);
144 of_node_put(nvram);
145
146 ppc_md.nvram_read = pSeries_nvram_read;
147 ppc_md.nvram_write = pSeries_nvram_write;
148 ppc_md.nvram_size = pSeries_nvram_get_size;
149
150 return 0;
151 }
152