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
  21 static loff_t nvram_llseek(struct file *file, loff_t offset, int origin)
  22 {
  23         switch (origin) {
  24         case 1:
  25                 offset += file->f_pos;
  26                 break;
  27         case 2:
  28                 offset += NVRAM_SIZE;
  29                 break;
  30         }
  31         if (offset < 0)
  32                 return -EINVAL;
  33
  34         file->f_pos = offset;
  35         return file->f_pos;
  36 }
  37
  38 static ssize_t read_nvram(struct file *file, char __user *buf,
  39                           size_t count, loff_t *ppos)
  40 {
  41         unsigned int i;
  42         char __user *p = buf;
  43
  44         if (!access_ok(VERIFY_WRITE, buf, count))
  45                 return -EFAULT;
  46         if (*ppos >= NVRAM_SIZE)
  47                 return 0;
  48         for (i = *ppos; count > 0 && i < NVRAM_SIZE; ++i, ++p, --count)
  49                 if (__put_user(nvram_read_byte(i), p))
  50                         return -EFAULT;
  51         *ppos = i;
  52         return p - buf;
  53 }
  54
  55 static ssize_t write_nvram(struct file *file, const char __user *buf,
  56                            size_t count, loff_t *ppos)
  57 {
  58         unsigned int i;
  59         const char __user *p = buf;
  60         char c;
  61
  62         if (!access_ok(VERIFY_READ, buf, count))
  63                 return -EFAULT;
  64         if (*ppos >= NVRAM_SIZE)
  65                 return 0;
  66         for (i = *ppos; count > 0 && i < NVRAM_SIZE; ++i, ++p, --count) {
  67                 if (__get_user(c, p))
  68                         return -EFAULT;
  69                 nvram_write_byte(c, i);
  70         }
  71         *ppos = i;
  72         return p - buf;
  73 }
  74
  75 static long nvram_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
  76 {
  77         switch(cmd) {
  78                 case PMAC_NVRAM_GET_OFFSET:
  79                 {
  80                         int part, offset;
  81                         if (copy_from_user(&part, (void __user*)arg, sizeof(part)) != 0)
  82                                 return -EFAULT;
  83                         if (part < pmac_nvram_OF || part > pmac_nvram_NR)
  84                                 return -EINVAL;
  85                         offset = pmac_get_partition(part);
  86                         if (copy_to_user((void __user*)arg, &offset, sizeof(offset)) != 0)
  87                                 return -EFAULT;
  88                         break;
  89                 }
  90
  91                 default:
  92                         return -EINVAL;
  93         }
  94
  95         return 0;
  96 }
  97
  98 const struct file_operations nvram_fops = {
  99         .owner          = THIS_MODULE,
 100         .llseek         = nvram_llseek,
 101         .read           = read_nvram,
 102         .write          = write_nvram,
 103         .unlocked_ioctl = nvram_ioctl,
 104 };
 105
 106 static struct miscdevice nvram_dev = {
 107         NVRAM_MINOR,
 108         "nvram",
 109         &nvram_fops
 110 };
 111
 112 int __init nvram_init(void)
 113 {
 114         printk(KERN_INFO "Macintosh non-volatile memory driver v%s\n",
 115                 NVRAM_VERSION);
 116         return misc_register(&nvram_dev);
 117 }
 118
 119 void __exit nvram_cleanup(void)
 120 {
 121         misc_deregister( &nvram_dev );
 122 }
 123
 124 module_init(nvram_init);
 125 module_exit(nvram_cleanup);
 126 MODULE_LICENSE("GPL");