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
 21static loff_t nvram_llseek(struct file *file, loff_t offset, int origin)
 22{
 23	switch (origin) {
 24	case 0:
 25		break;
 26	case 1:
 27		offset += file->f_pos;
 28		break;
 29	case 2:
 30		offset += NVRAM_SIZE;
 31		break;
 32	default:
 33		offset = -1;
 34	}
 35	if (offset < 0)
 36		return -EINVAL;
 37
 38	file->f_pos = offset;
 39	return file->f_pos;
 40}
 41
 42static ssize_t read_nvram(struct file *file, char __user *buf,
 43			  size_t count, loff_t *ppos)
 44{
 45	unsigned int i;
 46	char __user *p = buf;
 47
 48	if (!access_ok(VERIFY_WRITE, buf, count))
 49		return -EFAULT;
 50	if (*ppos >= NVRAM_SIZE)
 51		return 0;
 52	for (i = *ppos; count > 0 && i < NVRAM_SIZE; ++i, ++p, --count)
 53		if (__put_user(nvram_read_byte(i), p))
 54			return -EFAULT;
 55	*ppos = i;
 56	return p - buf;
 57}
 58
 59static ssize_t write_nvram(struct file *file, const char __user *buf,
 60			   size_t count, loff_t *ppos)
 61{
 62	unsigned int i;
 63	const char __user *p = buf;
 64	char c;
 65
 66	if (!access_ok(VERIFY_READ, buf, count))
 67		return -EFAULT;
 68	if (*ppos >= NVRAM_SIZE)
 69		return 0;
 70	for (i = *ppos; count > 0 && i < NVRAM_SIZE; ++i, ++p, --count) {
 71		if (__get_user(c, p))
 72			return -EFAULT;
 73		nvram_write_byte(c, i);
 74	}
 75	*ppos = i;
 76	return p - buf;
 77}
 78
 79static long nvram_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 80{
 81	switch(cmd) {
 82		case PMAC_NVRAM_GET_OFFSET:
 83		{
 84			int part, offset;
 85			if (copy_from_user(&part, (void __user*)arg, sizeof(part)) != 0)
 86				return -EFAULT;
 87			if (part < pmac_nvram_OF || part > pmac_nvram_NR)
 88				return -EINVAL;
 89			offset = pmac_get_partition(part);
 90			if (copy_to_user((void __user*)arg, &offset, sizeof(offset)) != 0)
 91				return -EFAULT;
 92			break;
 93		}
 94
 95		default:
 96			return -EINVAL;
 97	}
 98
 99	return 0;
100}
101
102const struct file_operations nvram_fops = {
103	.owner		= THIS_MODULE,
104	.llseek		= nvram_llseek,
105	.read		= read_nvram,
106	.write		= write_nvram,
107	.unlocked_ioctl	= nvram_ioctl,
108};
109
110static struct miscdevice nvram_dev = {
111	NVRAM_MINOR,
112	"nvram",
113	&nvram_fops
114};
115
116int __init nvram_init(void)
117{
118	printk(KERN_INFO "Macintosh non-volatile memory driver v%s\n",
119		NVRAM_VERSION);
120	return misc_register(&nvram_dev);
121}
122
123void __exit nvram_cleanup(void)
124{
125        misc_deregister( &nvram_dev );
126}
127
128module_init(nvram_init);
129module_exit(nvram_cleanup);
130MODULE_LICENSE("GPL");