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