parport_pc: show the detection of a 2 serial port ITE8874 chip
[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 <linux/smp_lock.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 ssize_t nvram_len;
32
33 static loff_t nvram_llseek(struct file *file, loff_t offset, int origin)
34 {
35         switch (origin) {
36         case 1:
37                 offset += file->f_pos;
38                 break;
39         case 2:
40                 offset += nvram_len;
41                 break;
42         }
43         if (offset < 0)
44                 return -EINVAL;
45
46         file->f_pos = offset;
47
48         return file->f_pos;
49 }
50
51 static ssize_t read_nvram(struct file *file, char __user *buf,
52                           size_t count, loff_t *ppos)
53 {
54         unsigned int i;
55         char __user *p = buf;
56
57         if (!access_ok(VERIFY_WRITE, buf, count))
58                 return -EFAULT;
59         if (*ppos >= nvram_len)
60                 return 0;
61         for (i = *ppos; count > 0 && i < nvram_len; ++i, ++p, --count)
62                 if (__put_user(nvram_read_byte(i), p))
63                         return -EFAULT;
64         *ppos = i;
65         return p - buf;
66 }
67
68 static ssize_t write_nvram(struct file *file, const char __user *buf,
69                            size_t count, loff_t *ppos)
70 {
71         unsigned int i;
72         const char __user *p = buf;
73         char c;
74
75         if (!access_ok(VERIFY_READ, buf, count))
76                 return -EFAULT;
77         if (*ppos >= nvram_len)
78                 return 0;
79         for (i = *ppos; count > 0 && i < nvram_len; ++i, ++p, --count) {
80                 if (__get_user(c, p))
81                         return -EFAULT;
82                 nvram_write_byte(c, i);
83         }
84         *ppos = i;
85         return p - buf;
86 }
87
88 static int nvram_ioctl(struct file *file, 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 static long nvram_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
120 {
121         int ret;
122
123         lock_kernel();
124         ret = nvram_ioctl(file, cmd, arg);
125         unlock_kernel();
126
127         return ret;
128 }
129
130 const struct file_operations nvram_fops = {
131         .owner          = THIS_MODULE,
132         .llseek         = nvram_llseek,
133         .read           = read_nvram,
134         .write          = write_nvram,
135         .unlocked_ioctl = nvram_unlocked_ioctl,
136 };
137
138 static struct miscdevice nvram_dev = {
139         NVRAM_MINOR,
140         "nvram",
141         &nvram_fops
142 };
143
144 int __init nvram_init(void)
145 {
146         int ret = 0;
147
148         printk(KERN_INFO "Generic non-volatile memory driver v%s\n",
149                 NVRAM_VERSION);
150         ret = misc_register(&nvram_dev);
151         if (ret != 0)
152                 goto out;
153
154         nvram_len = nvram_get_size();
155         if (nvram_len < 0)
156                 nvram_len = NVRAM_SIZE;
157
158 out:
159         return ret;
160 }
161
162 void __exit nvram_cleanup(void)
163 {
164         misc_deregister( &nvram_dev );
165 }
166
167 module_init(nvram_init);
168 module_exit(nvram_cleanup);
169 MODULE_LICENSE("GPL");