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Merge branch 'for-2.6.37' of git://git.kernel.org/pub/scm/linux/kernel/git/lrg/asoc...
[karo-tx-linux.git] / drivers / char / generic_nvram.c
1 /*
2  * Generic /dev/nvram driver for architectures providing some
3  * "generic" hooks, that is :
4  *
5  * nvram_read_byte, nvram_write_byte, nvram_sync, nvram_get_size
6  *
7  * Note that an additional hook is supported for PowerMac only
8  * for getting the nvram "partition" informations
9  *
10  */
11
12 #define NVRAM_VERSION "1.1"
13
14 #include <linux/module.h>
15
16 #include <linux/types.h>
17 #include <linux/errno.h>
18 #include <linux/fs.h>
19 #include <linux/miscdevice.h>
20 #include <linux/fcntl.h>
21 #include <linux/init.h>
22 #include <linux/mutex.h>
23 #include <asm/uaccess.h>
24 #include <asm/nvram.h>
25 #ifdef CONFIG_PPC_PMAC
26 #include <asm/machdep.h>
27 #endif
28
29 #define NVRAM_SIZE      8192
30
31 static DEFINE_MUTEX(nvram_mutex);
32 static ssize_t nvram_len;
33
34 static loff_t nvram_llseek(struct file *file, loff_t offset, int origin)
35 {
36         switch (origin) {
37         case 1:
38                 offset += file->f_pos;
39                 break;
40         case 2:
41                 offset += nvram_len;
42                 break;
43         }
44         if (offset < 0)
45                 return -EINVAL;
46
47         file->f_pos = offset;
48
49         return file->f_pos;
50 }
51
52 static ssize_t read_nvram(struct file *file, char __user *buf,
53                           size_t count, loff_t *ppos)
54 {
55         unsigned int i;
56         char __user *p = buf;
57
58         if (!access_ok(VERIFY_WRITE, buf, count))
59                 return -EFAULT;
60         if (*ppos >= nvram_len)
61                 return 0;
62         for (i = *ppos; count > 0 && i < nvram_len; ++i, ++p, --count)
63                 if (__put_user(nvram_read_byte(i), p))
64                         return -EFAULT;
65         *ppos = i;
66         return p - buf;
67 }
68
69 static ssize_t write_nvram(struct file *file, const char __user *buf,
70                            size_t count, loff_t *ppos)
71 {
72         unsigned int i;
73         const char __user *p = buf;
74         char c;
75
76         if (!access_ok(VERIFY_READ, buf, count))
77                 return -EFAULT;
78         if (*ppos >= nvram_len)
79                 return 0;
80         for (i = *ppos; count > 0 && i < nvram_len; ++i, ++p, --count) {
81                 if (__get_user(c, p))
82                         return -EFAULT;
83                 nvram_write_byte(c, i);
84         }
85         *ppos = i;
86         return p - buf;
87 }
88
89 static int nvram_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
90 {
91         switch(cmd) {
92 #ifdef CONFIG_PPC_PMAC
93         case OBSOLETE_PMAC_NVRAM_GET_OFFSET:
94                 printk(KERN_WARNING "nvram: Using obsolete PMAC_NVRAM_GET_OFFSET ioctl\n");
95         case IOC_NVRAM_GET_OFFSET: {
96                 int part, offset;
97
98                 if (!machine_is(powermac))
99                         return -EINVAL;
100                 if (copy_from_user(&part, (void __user*)arg, sizeof(part)) != 0)
101                         return -EFAULT;
102                 if (part < pmac_nvram_OF || part > pmac_nvram_NR)
103                         return -EINVAL;
104                 offset = pmac_get_partition(part);
105                 if (copy_to_user((void __user*)arg, &offset, sizeof(offset)) != 0)
106                         return -EFAULT;
107                 break;
108         }
109 #endif /* CONFIG_PPC_PMAC */
110         case IOC_NVRAM_SYNC:
111                 nvram_sync();
112                 break;
113         default:
114                 return -EINVAL;
115         }
116
117         return 0;
118 }
119
120 static long nvram_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
121 {
122         int ret;
123
124         mutex_lock(&nvram_mutex);
125         ret = nvram_ioctl(file, cmd, arg);
126         mutex_unlock(&nvram_mutex);
127
128         return ret;
129 }
130
131 const struct file_operations nvram_fops = {
132         .owner          = THIS_MODULE,
133         .llseek         = nvram_llseek,
134         .read           = read_nvram,
135         .write          = write_nvram,
136         .unlocked_ioctl = nvram_unlocked_ioctl,
137 };
138
139 static struct miscdevice nvram_dev = {
140         NVRAM_MINOR,
141         "nvram",
142         &nvram_fops
143 };
144
145 int __init nvram_init(void)
146 {
147         int ret = 0;
148
149         printk(KERN_INFO "Generic non-volatile memory driver v%s\n",
150                 NVRAM_VERSION);
151         ret = misc_register(&nvram_dev);
152         if (ret != 0)
153                 goto out;
154
155         nvram_len = nvram_get_size();
156         if (nvram_len < 0)
157                 nvram_len = NVRAM_SIZE;
158
159 out:
160         return ret;
161 }
162
163 void __exit nvram_cleanup(void)
164 {
165         misc_deregister( &nvram_dev );
166 }
167
168 module_init(nvram_init);
169 module_exit(nvram_cleanup);
170 MODULE_LICENSE("GPL");