[deliverable/linux.git] / arch / um / drivers / random.c

/* Copyright (C) 2005 - 2008 Jeff Dike <jdike@{linux.intel,addtoit}.com> */

/* Much of this ripped from drivers/char/hw_random.c, see there for other
 * copyright.
 *
 * This software may be used and distributed according to the terms
 * of the GNU General Public License, incorporated herein by reference.
 */
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/interrupt.h>
#include <linux/miscdevice.h>
#include <linux/delay.h>
#include <asm/uaccess.h>
#include <irq_kern.h>
#include <os.h>

/*
 * core module and version information
 */
#define RNG_VERSION "1.0.0"
#define RNG_MODULE_NAME "hw_random"

#define RNG_MISCDEV_MINOR		183 /* official */

/* Changed at init time, in the non-modular case, and at module load
 * time, in the module case.  Presumably, the module subsystem
 * protects against a module being loaded twice at the same time.
 */
static int random_fd = -1;
static DECLARE_WAIT_QUEUE_HEAD(host_read_wait);

static int rng_dev_open (struct inode *inode, struct file *filp)
{
	/* enforce read-only access to this chrdev */
	if ((filp->f_mode & FMODE_READ) == 0)
		return -EINVAL;
	if ((filp->f_mode & FMODE_WRITE) != 0)
		return -EINVAL;

	return 0;
}

static atomic_t host_sleep_count = ATOMIC_INIT(0);

static ssize_t rng_dev_read (struct file *filp, char __user *buf, size_t size,
			     loff_t *offp)
{
	u32 data;
	int n, ret = 0, have_data;

	while (size) {
		n = os_read_file(random_fd, &data, sizeof(data));
		if (n > 0) {
			have_data = n;
			while (have_data && size) {
				if (put_user((u8) data, buf++)) {
					ret = ret ? : -EFAULT;
					break;
				}
				size--;
				ret++;
				have_data--;
				data >>= 8;
			}
		}
		else if (n == -EAGAIN) {
			DECLARE_WAITQUEUE(wait, current);

			if (filp->f_flags & O_NONBLOCK)
				return ret ? : -EAGAIN;

			atomic_inc(&host_sleep_count);
			reactivate_fd(random_fd, RANDOM_IRQ);
			add_sigio_fd(random_fd);

			add_wait_queue(&host_read_wait, &wait);
			set_task_state(current, TASK_INTERRUPTIBLE);

			schedule();
			remove_wait_queue(&host_read_wait, &wait);

			if (atomic_dec_and_test(&host_sleep_count)) {
				ignore_sigio_fd(random_fd);
				deactivate_fd(random_fd, RANDOM_IRQ);
			}
		}
		else
			return n;

		if (signal_pending (current))
			return ret ? : -ERESTARTSYS;
	}
	return ret;
}

static const struct file_operations rng_chrdev_ops = {
	.owner		= THIS_MODULE,
	.open		= rng_dev_open,
	.read		= rng_dev_read,
	.llseek		= noop_llseek,
};

/* rng_init shouldn't be called more than once at boot time */
static struct miscdevice rng_miscdev = {
	RNG_MISCDEV_MINOR,
	RNG_MODULE_NAME,
	&rng_chrdev_ops,
};

static irqreturn_t random_interrupt(int irq, void *data)
{
	wake_up(&host_read_wait);

	return IRQ_HANDLED;
}

/*
 * rng_init - initialize RNG module
 */
static int __init rng_init (void)
{
	int err;

	err = os_open_file("/dev/random", of_read(OPENFLAGS()), 0);
	if (err < 0)
		goto out;

	random_fd = err;

	err = um_request_irq(RANDOM_IRQ, random_fd, IRQ_READ, random_interrupt,
			     0, "random", NULL);
	if (err)
		goto err_out_cleanup_hw;

	sigio_broken(random_fd, 1);

	err = misc_register (&rng_miscdev);
	if (err) {
		printk (KERN_ERR RNG_MODULE_NAME ": misc device register "
			"failed\n");
		goto err_out_cleanup_hw;
	}
out:
	return err;

err_out_cleanup_hw:
	os_close_file(random_fd);
	random_fd = -1;
	goto out;
}

/*
 * rng_cleanup - shutdown RNG module
 */
static void __exit rng_cleanup (void)
{
	os_close_file(random_fd);
	misc_deregister (&rng_miscdev);
}

module_init (rng_init);
module_exit (rng_cleanup);

MODULE_DESCRIPTION("UML Host Random Number Generator (RNG) driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
3d88958e JD	1	/* Copyright (C) 2005 - 2008 Jeff Dike <jdike@{linux.intel,addtoit}.com> */
3d88958e JD	2
567b5650 PBG	3	/* Much of this ripped from drivers/char/hw_random.c, see there for other
	4	* copyright.
	5	*
	6	* This software may be used and distributed according to the terms
	7	* of the GNU General Public License, incorporated herein by reference.
	8	*/
8192ab42	9	#include <linux/sched.h>
1da177e4 LT	10	#include <linux/module.h>
1da177e4 LT	11	#include <linux/fs.h>
5d33e4d7	12	#include <linux/interrupt.h>
1da177e4 LT	13	#include <linux/miscdevice.h>
	14	#include <linux/delay.h>
	15	#include <asm/uaccess.h>
37185b33 AV	16	#include <irq_kern.h>
37185b33 AV	17	#include <os.h>
1da177e4 LT	18
	19	/*
	20	* core module and version information
	21	*/
	22	#define RNG_VERSION "1.0.0"
5d33e4d7	23	#define RNG_MODULE_NAME "hw_random"
1da177e4 LT	24
	25	#define RNG_MISCDEV_MINOR 183 /* official */
	26
730760e9 JD	27	/* Changed at init time, in the non-modular case, and at module load
	28	* time, in the module case. Presumably, the module subsystem
	29	* protects against a module being loaded twice at the same time.
	30	*/
1da177e4	31	static int random_fd = -1;
5d33e4d7	32	static DECLARE_WAIT_QUEUE_HEAD(host_read_wait);
1da177e4 LT	33
	34	static int rng_dev_open (struct inode inode, struct file filp)
	35	{
	36	/* enforce read-only access to this chrdev */
	37	if ((filp->f_mode & FMODE_READ) == 0)
	38	return -EINVAL;
3d88958e	39	if ((filp->f_mode & FMODE_WRITE) != 0)
1da177e4 LT	40	return -EINVAL;
	41
	42	return 0;
	43	}
	44
5d33e4d7 JD	45	static atomic_t host_sleep_count = ATOMIC_INIT(0);
5d33e4d7 JD	46
1da177e4	47	static ssize_t rng_dev_read (struct file filp, char __user buf, size_t size,
3d88958e	48	loff_t *offp)
1da177e4	49	{
3d88958e JD	50	u32 data;
	51	int n, ret = 0, have_data;
	52
	53	while (size) {
	54	n = os_read_file(random_fd, &data, sizeof(data));
	55	if (n > 0) {
	56	have_data = n;
	57	while (have_data && size) {
	58	if (put_user((u8) data, buf++)) {
	59	ret = ret ? : -EFAULT;
	60	break;
	61	}
	62	size--;
	63	ret++;
	64	have_data--;
	65	data >>= 8;
	66	}
	67	}
	68	else if (n == -EAGAIN) {
5d33e4d7 JD	69	DECLARE_WAITQUEUE(wait, current);
5d33e4d7 JD	70
3d88958e JD	71	if (filp->f_flags & O_NONBLOCK)
3d88958e JD	72	return ret ? : -EAGAIN;
1da177e4	73
5d33e4d7 JD	74	atomic_inc(&host_sleep_count);
	75	reactivate_fd(random_fd, RANDOM_IRQ);
	76	add_sigio_fd(random_fd);
	77
	78	add_wait_queue(&host_read_wait, &wait);
	79	set_task_state(current, TASK_INTERRUPTIBLE);
	80
	81	schedule();
5d33e4d7 JD	82	remove_wait_queue(&host_read_wait, &wait);
	83
	84	if (atomic_dec_and_test(&host_sleep_count)) {
	85	ignore_sigio_fd(random_fd);
	86	deactivate_fd(random_fd, RANDOM_IRQ);
	87	}
3d88958e JD	88	}
	89	else
	90	return n;
	91
1da177e4 LT	92	if (signal_pending (current))
	93	return ret ? : -ERESTARTSYS;
	94	}
	95	return ret;
	96	}
	97
5e7672ec	98	static const struct file_operations rng_chrdev_ops = {
1da177e4 LT	99	.owner = THIS_MODULE,
	100	.open = rng_dev_open,
	101	.read = rng_dev_read,
6038f373	102	.llseek = noop_llseek,
1da177e4 LT	103	};
1da177e4 LT	104
99b0278f	105	/* rng_init shouldn't be called more than once at boot time */
1da177e4 LT	106	static struct miscdevice rng_miscdev = {
	107	RNG_MISCDEV_MINOR,
	108	RNG_MODULE_NAME,
	109	&rng_chrdev_ops,
	110	};
	111
5d33e4d7 JD	112	static irqreturn_t random_interrupt(int irq, void *data)
	113	{
	114	wake_up(&host_read_wait);
	115
	116	return IRQ_HANDLED;
	117	}
	118
1da177e4 LT	119	/*
	120	* rng_init - initialize RNG module
	121	*/
	122	static int __init rng_init (void)
	123	{
	124	int err;
	125
3d88958e JD	126	err = os_open_file("/dev/random", of_read(OPENFLAGS()), 0);
	127	if (err < 0)
	128	goto out;
1da177e4	129
3d88958e	130	random_fd = err;
1da177e4	131
5d33e4d7	132	err = um_request_irq(RANDOM_IRQ, random_fd, IRQ_READ, random_interrupt,
aab94460	133	0, "random", NULL);
3d88958e	134	if (err)
1da177e4 LT	135	goto err_out_cleanup_hw;
1da177e4 LT	136
5d33e4d7 JD	137	sigio_broken(random_fd, 1);
5d33e4d7 JD	138
1da177e4 LT	139	err = misc_register (&rng_miscdev);
1da177e4 LT	140	if (err) {
3d88958e JD	141	printk (KERN_ERR RNG_MODULE_NAME ": misc device register "
3d88958e JD	142	"failed\n");
1da177e4 LT	143	goto err_out_cleanup_hw;
1da177e4 LT	144	}
3d88958e JD	145	out:
3d88958e JD	146	return err;
1da177e4	147
3d88958e	148	err_out_cleanup_hw:
5d33e4d7	149	os_close_file(random_fd);
3d88958e JD	150	random_fd = -1;
3d88958e JD	151	goto out;
1da177e4 LT	152	}
	153
	154	/*
	155	* rng_cleanup - shutdown RNG module
	156	*/
	157	static void __exit rng_cleanup (void)
	158	{
5d33e4d7	159	os_close_file(random_fd);
1da177e4 LT	160	misc_deregister (&rng_miscdev);
	161	}
	162
	163	module_init (rng_init);
	164	module_exit (rng_cleanup);
567b5650 PBG	165
	166	MODULE_DESCRIPTION("UML Host Random Number Generator (RNG) driver");
	167	MODULE_LICENSE("GPL");