/* * Generic /dev/nvram driver for architectures providing some * "generic" hooks, that is : * * nvram_read_byte, nvram_write_byte, nvram_sync * * Note that an additional hook is supported for PowerMac only * for getting the nvram "partition" informations * */#define NVRAM_VERSION "1.1"#include <linux/module.h>#include <linux/types.h>#include <linux/errno.h>#include <linux/fs.h>#include <linux/miscdevice.h>#include <linux/fcntl.h>#include <linux/init.h>#include <linux/smp_lock.h>#include <asm/uaccess.h>#include <asm/nvram.h>#define NVRAM_SIZE	8192static loff_t nvram_llseek(struct file *file, loff_t offset, int origin){	lock_kernel();	switch (origin) {	case 1:		offset += file->f_pos;		break;	case 2:		offset += NVRAM_SIZE;		break;	}	if (offset < 0) {		unlock_kernel();		return -EINVAL;	}	file->f_pos = offset;	unlock_kernel();	return file->f_pos;}static ssize_t read_nvram(struct file *file, char __user *buf,			  size_t count, loff_t *ppos){	unsigned int i;	char __user *p = buf;	if (!access_ok(VERIFY_WRITE, buf, count))		return -EFAULT;	if (*ppos >= NVRAM_SIZE)		return 0;	for (i = *ppos; count > 0 && i < NVRAM_SIZE; ++i, ++p, --count)		if (__put_user(nvram_read_byte(i), p))			return -EFAULT;	*ppos = i;	return p - buf;}static ssize_t write_nvram(struct file *file, const char __user *buf,			   size_t count, loff_t *ppos){	unsigned int i;	const char __user *p = buf;	char c;	if (!access_ok(VERIFY_READ, buf, count))		return -EFAULT;	if (*ppos >= NVRAM_SIZE)		return 0;	for (i = *ppos; count > 0 && i < NVRAM_SIZE; ++i, ++p, --count) {		if (__get_user(c, p))			return -EFAULT;		nvram_write_byte(c, i);	}	*ppos = i;	return p - buf;}static int nvram_ioctl(struct inode *inode, struct file *file,	unsigned int cmd, unsigned long arg){	switch(cmd) {#ifdef CONFIG_PPC_PMAC	case OBSOLETE_PMAC_NVRAM_GET_OFFSET:		printk(KERN_WARNING "nvram: Using obsolete PMAC_NVRAM_GET_OFFSET ioctl\n");	case IOC_NVRAM_GET_OFFSET: {		int part, offset;		if (_machine != _MACH_Pmac)			return -EINVAL;		if (copy_from_user(&part, (void __user*)arg, sizeof(part)) != 0)			return -EFAULT;		if (part < pmac_nvram_OF || part > pmac_nvram_NR)			return -EINVAL;		offset = pmac_get_partition(part);		if (copy_to_user((void __user*)arg, &offset, sizeof(offset)) != 0)			return -EFAULT;		break;	}#endif /* CONFIG_PPC_PMAC */	case IOC_NVRAM_SYNC:		nvram_sync();		break;	default:		return -EINVAL;	}	return 0;}struct file_operations nvram_fops = {	.owner		= THIS_MODULE,	.llseek		= nvram_llseek,	.read		= read_nvram,	.write		= write_nvram,	.ioctl		= nvram_ioctl,};static struct miscdevice nvram_dev = {	NVRAM_MINOR,	"nvram",	&nvram_fops};int __init nvram_init(void){	printk(KERN_INFO "Macintosh non-volatile memory driver v%s\n",		NVRAM_VERSION);	return misc_register(&nvram_dev);}void __exit nvram_cleanup(void){        misc_deregister( &nvram_dev );}module_init(nvram_init);module_exit(nvram_cleanup);MODULE_LICENSE("GPL");