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Merge branch 'tty-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6
[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 0:
38                 break;
39         case 1:
40                 offset += file->f_pos;
41                 break;
42         case 2:
43                 offset += nvram_len;
44                 break;
45         default:
46                 offset = -1;
47         }
48         if (offset < 0)
49                 return -EINVAL;
50
51         file->f_pos = offset;
52
53         return file->f_pos;
54 }
55
56 static ssize_t read_nvram(struct file *file, char __user *buf,
57                           size_t count, loff_t *ppos)
58 {
59         unsigned int i;
60         char __user *p = buf;
61
62         if (!access_ok(VERIFY_WRITE, buf, count))
63                 return -EFAULT;
64         if (*ppos >= nvram_len)
65                 return 0;
66         for (i = *ppos; count > 0 && i < nvram_len; ++i, ++p, --count)
67                 if (__put_user(nvram_read_byte(i), p))
68                         return -EFAULT;
69         *ppos = i;
70         return p - buf;
71 }
72
73 static ssize_t write_nvram(struct file *file, const char __user *buf,
74                            size_t count, loff_t *ppos)
75 {
76         unsigned int i;
77         const char __user *p = buf;
78         char c;
79
80         if (!access_ok(VERIFY_READ, buf, count))
81                 return -EFAULT;
82         if (*ppos >= nvram_len)
83                 return 0;
84         for (i = *ppos; count > 0 && i < nvram_len; ++i, ++p, --count) {
85                 if (__get_user(c, p))
86                         return -EFAULT;
87                 nvram_write_byte(c, i);
88         }
89         *ppos = i;
90         return p - buf;
91 }
92
93 static int nvram_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
94 {
95         switch(cmd) {
96 #ifdef CONFIG_PPC_PMAC
97         case OBSOLETE_PMAC_NVRAM_GET_OFFSET:
98                 printk(KERN_WARNING "nvram: Using obsolete PMAC_NVRAM_GET_OFFSET ioctl\n");
99         case IOC_NVRAM_GET_OFFSET: {
100                 int part, offset;
101
102                 if (!machine_is(powermac))
103                         return -EINVAL;
104                 if (copy_from_user(&part, (void __user*)arg, sizeof(part)) != 0)
105                         return -EFAULT;
106                 if (part < pmac_nvram_OF || part > pmac_nvram_NR)
107                         return -EINVAL;
108                 offset = pmac_get_partition(part);
109                 if (copy_to_user((void __user*)arg, &offset, sizeof(offset)) != 0)
110                         return -EFAULT;
111                 break;
112         }
113 #endif /* CONFIG_PPC_PMAC */
114         case IOC_NVRAM_SYNC:
115                 nvram_sync();
116                 break;
117         default:
118                 return -EINVAL;
119         }
120
121         return 0;
122 }
123
124 static long nvram_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
125 {
126         int ret;
127
128         mutex_lock(&nvram_mutex);
129         ret = nvram_ioctl(file, cmd, arg);
130         mutex_unlock(&nvram_mutex);
131
132         return ret;
133 }
134
135 const struct file_operations nvram_fops = {
136         .owner          = THIS_MODULE,
137         .llseek         = nvram_llseek,
138         .read           = read_nvram,
139         .write          = write_nvram,
140         .unlocked_ioctl = nvram_unlocked_ioctl,
141 };
142
143 static struct miscdevice nvram_dev = {
144         NVRAM_MINOR,
145         "nvram",
146         &nvram_fops
147 };
148
149 int __init nvram_init(void)
150 {
151         int ret = 0;
152
153         printk(KERN_INFO "Generic non-volatile memory driver v%s\n",
154                 NVRAM_VERSION);
155         ret = misc_register(&nvram_dev);
156         if (ret != 0)
157                 goto out;
158
159         nvram_len = nvram_get_size();
160         if (nvram_len < 0)
161                 nvram_len = NVRAM_SIZE;
162
163 out:
164         return ret;
165 }
166
167 void __exit nvram_cleanup(void)
168 {
169         misc_deregister( &nvram_dev );
170 }
171
172 module_init(nvram_init);
173 module_exit(nvram_cleanup);
174 MODULE_LICENSE("GPL");