Pull bugzilla-8459 into release branch
[linux-2.6] / drivers / macintosh / nvram.c
1 /*
2  * /dev/nvram driver for Power Macintosh.
3  */
4
5 #define NVRAM_VERSION "1.0"
6
7 #include <linux/module.h>
8
9 #include <linux/types.h>
10 #include <linux/errno.h>
11 #include <linux/fs.h>
12 #include <linux/miscdevice.h>
13 #include <linux/fcntl.h>
14 #include <linux/nvram.h>
15 #include <linux/init.h>
16 #include <linux/smp_lock.h>
17 #include <asm/uaccess.h>
18 #include <asm/nvram.h>
19
20 #define NVRAM_SIZE      8192
21
22 static loff_t nvram_llseek(struct file *file, loff_t offset, int origin)
23 {
24         lock_kernel();
25         switch (origin) {
26         case 1:
27                 offset += file->f_pos;
28                 break;
29         case 2:
30                 offset += NVRAM_SIZE;
31                 break;
32         }
33         if (offset < 0) {
34                 unlock_kernel();
35                 return -EINVAL;
36         }
37         file->f_pos = offset;
38         unlock_kernel();
39         return file->f_pos;
40 }
41
42 static ssize_t read_nvram(struct file *file, char __user *buf,
43                           size_t count, loff_t *ppos)
44 {
45         unsigned int i;
46         char __user *p = buf;
47
48         if (!access_ok(VERIFY_WRITE, buf, count))
49                 return -EFAULT;
50         if (*ppos >= NVRAM_SIZE)
51                 return 0;
52         for (i = *ppos; count > 0 && i < NVRAM_SIZE; ++i, ++p, --count)
53                 if (__put_user(nvram_read_byte(i), p))
54                         return -EFAULT;
55         *ppos = i;
56         return p - buf;
57 }
58
59 static ssize_t write_nvram(struct file *file, const char __user *buf,
60                            size_t count, loff_t *ppos)
61 {
62         unsigned int i;
63         const char __user *p = buf;
64         char c;
65
66         if (!access_ok(VERIFY_READ, buf, count))
67                 return -EFAULT;
68         if (*ppos >= NVRAM_SIZE)
69                 return 0;
70         for (i = *ppos; count > 0 && i < NVRAM_SIZE; ++i, ++p, --count) {
71                 if (__get_user(c, p))
72                         return -EFAULT;
73                 nvram_write_byte(c, i);
74         }
75         *ppos = i;
76         return p - buf;
77 }
78
79 static int nvram_ioctl(struct inode *inode, struct file *file,
80         unsigned int cmd, unsigned long arg)
81 {
82         switch(cmd) {
83                 case PMAC_NVRAM_GET_OFFSET:
84                 {
85                         int part, offset;
86                         if (copy_from_user(&part, (void __user*)arg, sizeof(part)) != 0)
87                                 return -EFAULT;
88                         if (part < pmac_nvram_OF || part > pmac_nvram_NR)
89                                 return -EINVAL;
90                         offset = pmac_get_partition(part);
91                         if (copy_to_user((void __user*)arg, &offset, sizeof(offset)) != 0)
92                                 return -EFAULT;
93                         break;
94                 }
95
96                 default:
97                         return -EINVAL;
98         }
99
100         return 0;
101 }
102
103 const struct file_operations nvram_fops = {
104         .owner          = THIS_MODULE,
105         .llseek         = nvram_llseek,
106         .read           = read_nvram,
107         .write          = write_nvram,
108         .ioctl          = nvram_ioctl,
109 };
110
111 static struct miscdevice nvram_dev = {
112         NVRAM_MINOR,
113         "nvram",
114         &nvram_fops
115 };
116
117 int __init nvram_init(void)
118 {
119         printk(KERN_INFO "Macintosh non-volatile memory driver v%s\n",
120                 NVRAM_VERSION);
121         return misc_register(&nvram_dev);
122 }
123
124 void __exit nvram_cleanup(void)
125 {
126         misc_deregister( &nvram_dev );
127 }
128
129 module_init(nvram_init);
130 module_exit(nvram_cleanup);
131 MODULE_LICENSE("GPL");