Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6
[linux-2.6.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 <asm/uaccess.h>
23 #include <asm/nvram.h>
24 #ifdef CONFIG_PPC_PMAC
25 #include <asm/machdep.h>
26 #endif
27
28 #define NVRAM_SIZE      8192
29
30 static ssize_t nvram_len;
31
32 static loff_t nvram_llseek(struct file *file, loff_t offset, int origin)
33 {
34         switch (origin) {
35         case 1:
36                 offset += file->f_pos;
37                 break;
38         case 2:
39                 offset += nvram_len;
40                 break;
41         }
42         if (offset < 0)
43                 return -EINVAL;
44
45         file->f_pos = offset;
46
47         return file->f_pos;
48 }
49
50 static ssize_t read_nvram(struct file *file, char __user *buf,
51                           size_t count, loff_t *ppos)
52 {
53         unsigned int i;
54         char __user *p = buf;
55
56         if (!access_ok(VERIFY_WRITE, buf, count))
57                 return -EFAULT;
58         if (*ppos >= nvram_len)
59                 return 0;
60         for (i = *ppos; count > 0 && i < nvram_len; ++i, ++p, --count)
61                 if (__put_user(nvram_read_byte(i), p))
62                         return -EFAULT;
63         *ppos = i;
64         return p - buf;
65 }
66
67 static ssize_t write_nvram(struct file *file, const char __user *buf,
68                            size_t count, loff_t *ppos)
69 {
70         unsigned int i;
71         const char __user *p = buf;
72         char c;
73
74         if (!access_ok(VERIFY_READ, buf, count))
75                 return -EFAULT;
76         if (*ppos >= nvram_len)
77                 return 0;
78         for (i = *ppos; count > 0 && i < nvram_len; ++i, ++p, --count) {
79                 if (__get_user(c, p))
80                         return -EFAULT;
81                 nvram_write_byte(c, i);
82         }
83         *ppos = i;
84         return p - buf;
85 }
86
87 static int nvram_ioctl(struct inode *inode, struct file *file,
88         unsigned int cmd, unsigned long arg)
89 {
90         switch(cmd) {
91 #ifdef CONFIG_PPC_PMAC
92         case OBSOLETE_PMAC_NVRAM_GET_OFFSET:
93                 printk(KERN_WARNING "nvram: Using obsolete PMAC_NVRAM_GET_OFFSET ioctl\n");
94         case IOC_NVRAM_GET_OFFSET: {
95                 int part, offset;
96
97                 if (!machine_is(powermac))
98                         return -EINVAL;
99                 if (copy_from_user(&part, (void __user*)arg, sizeof(part)) != 0)
100                         return -EFAULT;
101                 if (part < pmac_nvram_OF || part > pmac_nvram_NR)
102                         return -EINVAL;
103                 offset = pmac_get_partition(part);
104                 if (copy_to_user((void __user*)arg, &offset, sizeof(offset)) != 0)
105                         return -EFAULT;
106                 break;
107         }
108 #endif /* CONFIG_PPC_PMAC */
109         case IOC_NVRAM_SYNC:
110                 nvram_sync();
111                 break;
112         default:
113                 return -EINVAL;
114         }
115
116         return 0;
117 }
118
119 const struct file_operations nvram_fops = {
120         .owner          = THIS_MODULE,
121         .llseek         = nvram_llseek,
122         .read           = read_nvram,
123         .write          = write_nvram,
124         .ioctl          = nvram_ioctl,
125 };
126
127 static struct miscdevice nvram_dev = {
128         NVRAM_MINOR,
129         "nvram",
130         &nvram_fops
131 };
132
133 int __init nvram_init(void)
134 {
135         int ret = 0;
136
137         printk(KERN_INFO "Generic non-volatile memory driver v%s\n",
138                 NVRAM_VERSION);
139         ret = misc_register(&nvram_dev);
140         if (ret != 0)
141                 goto out;
142
143         nvram_len = nvram_get_size();
144         if (nvram_len < 0)
145                 nvram_len = NVRAM_SIZE;
146
147 out:
148         return ret;
149 }
150
151 void __exit nvram_cleanup(void)
152 {
153         misc_deregister( &nvram_dev );
154 }
155
156 module_init(nvram_init);
157 module_exit(nvram_cleanup);
158 MODULE_LICENSE("GPL");