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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"); |