Root/
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"); |
175 |
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