Root/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 <asm/uaccess.h>
17#include <asm/nvram.h>
18
19#define NVRAM_SIZE 8192
20
21static loff_t nvram_llseek(struct file *file, loff_t offset, int origin)
22{
23    switch (origin) {
24    case 0:
25        break;
26    case 1:
27        offset += file->f_pos;
28        break;
29    case 2:
30        offset += NVRAM_SIZE;
31        break;
32    default:
33        offset = -1;
34    }
35    if (offset < 0)
36        return -EINVAL;
37
38    file->f_pos = offset;
39    return file->f_pos;
40}
41
42static 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
59static 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
79static long nvram_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
80{
81    switch(cmd) {
82        case PMAC_NVRAM_GET_OFFSET:
83        {
84            int part, offset;
85            if (copy_from_user(&part, (void __user*)arg, sizeof(part)) != 0)
86                return -EFAULT;
87            if (part < pmac_nvram_OF || part > pmac_nvram_NR)
88                return -EINVAL;
89            offset = pmac_get_partition(part);
90            if (copy_to_user((void __user*)arg, &offset, sizeof(offset)) != 0)
91                return -EFAULT;
92            break;
93        }
94
95        default:
96            return -EINVAL;
97    }
98
99    return 0;
100}
101
102const struct file_operations nvram_fops = {
103    .owner = THIS_MODULE,
104    .llseek = nvram_llseek,
105    .read = read_nvram,
106    .write = write_nvram,
107    .unlocked_ioctl = nvram_ioctl,
108};
109
110static struct miscdevice nvram_dev = {
111    NVRAM_MINOR,
112    "nvram",
113    &nvram_fops
114};
115
116int __init nvram_init(void)
117{
118    printk(KERN_INFO "Macintosh non-volatile memory driver v%s\n",
119        NVRAM_VERSION);
120    return misc_register(&nvram_dev);
121}
122
123void __exit nvram_cleanup(void)
124{
125        misc_deregister( &nvram_dev );
126}
127
128module_init(nvram_init);
129module_exit(nvram_cleanup);
130MODULE_LICENSE("GPL");
131

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