[deliverable/linux.git] / drivers / pps / pps.c

/*
 * PPS core file
 *
 *
 * Copyright (C) 2005-2009   Rodolfo Giometti <giometti@linux.it>
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/uaccess.h>
#include <linux/idr.h>
#include <linux/mutex.h>
#include <linux/cdev.h>
#include <linux/poll.h>
#include <linux/pps_kernel.h>
#include <linux/slab.h>

/*
 * Local variables
 */

static dev_t pps_devt;
static struct class *pps_class;

static DEFINE_MUTEX(pps_idr_lock);
static DEFINE_IDR(pps_idr);

/*
 * Char device methods
 */

static unsigned int pps_cdev_poll(struct file *file, poll_table *wait)
{
	struct pps_device *pps = file->private_data;

	poll_wait(file, &pps->queue, wait);

	return POLLIN | POLLRDNORM;
}

static int pps_cdev_fasync(int fd, struct file *file, int on)
{
	struct pps_device *pps = file->private_data;
	return fasync_helper(fd, file, on, &pps->async_queue);
}

static long pps_cdev_ioctl(struct file *file,
		unsigned int cmd, unsigned long arg)
{
	struct pps_device *pps = file->private_data;
	struct pps_kparams params;
	void __user *uarg = (void __user *) arg;
	int __user *iuarg = (int __user *) arg;
	int err;

	switch (cmd) {
	case PPS_GETPARAMS:
		dev_dbg(pps->dev, "PPS_GETPARAMS\n");

		spin_lock_irq(&pps->lock);

		/* Get the current parameters */
		params = pps->params;

		spin_unlock_irq(&pps->lock);

		err = copy_to_user(uarg, &params, sizeof(struct pps_kparams));
		if (err)
			return -EFAULT;

		break;

	case PPS_SETPARAMS:
		dev_dbg(pps->dev, "PPS_SETPARAMS\n");

		/* Check the capabilities */
		if (!capable(CAP_SYS_TIME))
			return -EPERM;

		err = copy_from_user(&params, uarg, sizeof(struct pps_kparams));
		if (err)
			return -EFAULT;
		if (!(params.mode & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR))) {
			dev_dbg(pps->dev, "capture mode unspecified (%x)\n",
								params.mode);
			return -EINVAL;
		}

		/* Check for supported capabilities */
		if ((params.mode & ~pps->info.mode) != 0) {
			dev_dbg(pps->dev, "unsupported capabilities (%x)\n",
								params.mode);
			return -EINVAL;
		}

		spin_lock_irq(&pps->lock);

		/* Save the new parameters */
		pps->params = params;

		/* Restore the read only parameters */
		if ((params.mode & (PPS_TSFMT_TSPEC | PPS_TSFMT_NTPFP)) == 0) {
			/* section 3.3 of RFC 2783 interpreted */
			dev_dbg(pps->dev, "time format unspecified (%x)\n",
								params.mode);
			pps->params.mode |= PPS_TSFMT_TSPEC;
		}
		if (pps->info.mode & PPS_CANWAIT)
			pps->params.mode |= PPS_CANWAIT;
		pps->params.api_version = PPS_API_VERS;

		spin_unlock_irq(&pps->lock);

		break;

	case PPS_GETCAP:
		dev_dbg(pps->dev, "PPS_GETCAP\n");

		err = put_user(pps->info.mode, iuarg);
		if (err)
			return -EFAULT;

		break;

	case PPS_FETCH: {
		struct pps_fdata fdata;
		unsigned int ev;

		dev_dbg(pps->dev, "PPS_FETCH\n");

		err = copy_from_user(&fdata, uarg, sizeof(struct pps_fdata));
		if (err)
			return -EFAULT;

		ev = pps->last_ev;

		/* Manage the timeout */
		if (fdata.timeout.flags & PPS_TIME_INVALID)
			err = wait_event_interruptible(pps->queue,
					ev != pps->last_ev);
		else {
			unsigned long ticks;

			dev_dbg(pps->dev, "timeout %lld.%09d\n",
					(long long) fdata.timeout.sec,
					fdata.timeout.nsec);
			ticks = fdata.timeout.sec * HZ;
			ticks += fdata.timeout.nsec / (NSEC_PER_SEC / HZ);

			if (ticks != 0) {
				err = wait_event_interruptible_timeout(
						pps->queue,
						ev != pps->last_ev,
						ticks);
				if (err == 0)
					return -ETIMEDOUT;
			}
		}

		/* Check for pending signals */
		if (err == -ERESTARTSYS) {
			dev_dbg(pps->dev, "pending signal caught\n");
			return -EINTR;
		}

		/* Return the fetched timestamp */
		spin_lock_irq(&pps->lock);

		fdata.info.assert_sequence = pps->assert_sequence;
		fdata.info.clear_sequence = pps->clear_sequence;
		fdata.info.assert_tu = pps->assert_tu;
		fdata.info.clear_tu = pps->clear_tu;
		fdata.info.current_mode = pps->current_mode;

		spin_unlock_irq(&pps->lock);

		err = copy_to_user(uarg, &fdata, sizeof(struct pps_fdata));
		if (err)
			return -EFAULT;

		break;
	}
	default:
		return -ENOTTY;
		break;
	}

	return 0;
}

static int pps_cdev_open(struct inode *inode, struct file *file)
{
	struct pps_device *pps = container_of(inode->i_cdev,
						struct pps_device, cdev);
	file->private_data = pps;

	return 0;
}

static int pps_cdev_release(struct inode *inode, struct file *file)
{
	return 0;
}

/*
 * Char device stuff
 */

static const struct file_operations pps_cdev_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.poll		= pps_cdev_poll,
	.fasync		= pps_cdev_fasync,
	.unlocked_ioctl	= pps_cdev_ioctl,
	.open		= pps_cdev_open,
	.release	= pps_cdev_release,
};

static void pps_device_destruct(struct device *dev)
{
	struct pps_device *pps = dev_get_drvdata(dev);

	/* release id here to protect others from using it while it's
	 * still in use */
	mutex_lock(&pps_idr_lock);
	idr_remove(&pps_idr, pps->id);
	mutex_unlock(&pps_idr_lock);

	kfree(dev);
	kfree(pps);
}

int pps_register_cdev(struct pps_device *pps)
{
	int err;
	dev_t devt;

	mutex_lock(&pps_idr_lock);
	/* Get new ID for the new PPS source */
	if (idr_pre_get(&pps_idr, GFP_KERNEL) == 0) {
		mutex_unlock(&pps_idr_lock);
		return -ENOMEM;
	}

	/* Now really allocate the PPS source.
	 * After idr_get_new() calling the new source will be freely available
	 * into the kernel.
	 */
	err = idr_get_new(&pps_idr, pps, &pps->id);
	mutex_unlock(&pps_idr_lock);

	if (err < 0)
		return err;

	pps->id &= MAX_ID_MASK;
	if (pps->id >= PPS_MAX_SOURCES) {
		pr_err("%s: too many PPS sources in the system\n",
					pps->info.name);
		err = -EBUSY;
		goto free_idr;
	}

	devt = MKDEV(MAJOR(pps_devt), pps->id);

	cdev_init(&pps->cdev, &pps_cdev_fops);
	pps->cdev.owner = pps->info.owner;

	err = cdev_add(&pps->cdev, devt, 1);
	if (err) {
		pr_err("%s: failed to add char device %d:%d\n",
				pps->info.name, MAJOR(pps_devt), pps->id);
		goto free_idr;
	}
	pps->dev = device_create(pps_class, pps->info.dev, devt, pps,
							"pps%d", pps->id);
	if (IS_ERR(pps->dev))
		goto del_cdev;

	pps->dev->release = pps_device_destruct;

	pr_debug("source %s got cdev (%d:%d)\n", pps->info.name,
			MAJOR(pps_devt), pps->id);

	return 0;

del_cdev:
	cdev_del(&pps->cdev);

free_idr:
	mutex_lock(&pps_idr_lock);
	idr_remove(&pps_idr, pps->id);
	mutex_unlock(&pps_idr_lock);

	return err;
}

void pps_unregister_cdev(struct pps_device *pps)
{
	device_destroy(pps_class, pps->dev->devt);
	cdev_del(&pps->cdev);
}

/*
 * Module stuff
 */

static void __exit pps_exit(void)
{
	class_destroy(pps_class);
	unregister_chrdev_region(pps_devt, PPS_MAX_SOURCES);
}

static int __init pps_init(void)
{
	int err;

	pps_class = class_create(THIS_MODULE, "pps");
	if (!pps_class) {
		pr_err("failed to allocate class\n");
		return -ENOMEM;
	}
	pps_class->dev_attrs = pps_attrs;

	err = alloc_chrdev_region(&pps_devt, 0, PPS_MAX_SOURCES, "pps");
	if (err < 0) {
		pr_err("failed to allocate char device region\n");
		goto remove_class;
	}

	pr_info("LinuxPPS API ver. %d registered\n", PPS_API_VERS);
	pr_info("Software ver. %s - Copyright 2005-2007 Rodolfo Giometti "
		"<giometti@linux.it>\n", PPS_VERSION);

	return 0;

remove_class:
	class_destroy(pps_class);

	return err;
}

subsys_initcall(pps_init);
module_exit(pps_exit);

MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
MODULE_DESCRIPTION("LinuxPPS support (RFC 2783) - ver. " PPS_VERSION);
MODULE_LICENSE("GPL");
Commit	Line	Data
eae9d2ba RG	1	/*
	2	* PPS core file
	3	*
	4	*
	5	* Copyright (C) 2005-2009 Rodolfo Giometti <giometti@linux.it>
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License as published by
	9	* the Free Software Foundation; either version 2 of the License, or
	10	* (at your option) any later version.
	11	*
	12	* This program is distributed in the hope that it will be useful,
	13	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	* GNU General Public License for more details.
	16	*
	17	* You should have received a copy of the GNU General Public License
	18	* along with this program; if not, write to the Free Software
	19	* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	20	*/
	21
7f7cce74	22	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
eae9d2ba RG	23
	24	#include <linux/kernel.h>
	25	#include <linux/module.h>
	26	#include <linux/init.h>
	27	#include <linux/sched.h>
	28	#include <linux/uaccess.h>
	29	#include <linux/idr.h>
2a5cd6e2	30	#include <linux/mutex.h>
eae9d2ba RG	31	#include <linux/cdev.h>
	32	#include <linux/poll.h>
	33	#include <linux/pps_kernel.h>
083e5866	34	#include <linux/slab.h>
eae9d2ba RG	35
	36	/*
	37	* Local variables
	38	*/
	39
	40	static dev_t pps_devt;
	41	static struct class *pps_class;
	42
2a5cd6e2	43	static DEFINE_MUTEX(pps_idr_lock);
083e5866 AG	44	static DEFINE_IDR(pps_idr);
083e5866 AG	45
eae9d2ba RG	46	/*
	47	* Char device methods
	48	*/
	49
	50	static unsigned int pps_cdev_poll(struct file file, poll_table wait)
	51	{
	52	struct pps_device *pps = file->private_data;
	53
	54	poll_wait(file, &pps->queue, wait);
	55
	56	return POLLIN \| POLLRDNORM;
	57	}
	58
	59	static int pps_cdev_fasync(int fd, struct file *file, int on)
	60	{
	61	struct pps_device *pps = file->private_data;
	62	return fasync_helper(fd, file, on, &pps->async_queue);
	63	}
	64
	65	static long pps_cdev_ioctl(struct file *file,
	66	unsigned int cmd, unsigned long arg)
	67	{
	68	struct pps_device *pps = file->private_data;
	69	struct pps_kparams params;
eae9d2ba RG	70	void __user uarg = (void __user ) arg;
	71	int __user iuarg = (int __user ) arg;
	72	int err;
	73
	74	switch (cmd) {
	75	case PPS_GETPARAMS:
7f7cce74	76	dev_dbg(pps->dev, "PPS_GETPARAMS\n");
eae9d2ba	77
cbf83cc5 RG	78	spin_lock_irq(&pps->lock);
	79
	80	/* Get the current parameters */
	81	params = pps->params;
	82
	83	spin_unlock_irq(&pps->lock);
	84
	85	err = copy_to_user(uarg, &params, sizeof(struct pps_kparams));
eae9d2ba RG	86	if (err)
	87	return -EFAULT;
	88
	89	break;
	90
	91	case PPS_SETPARAMS:
7f7cce74	92	dev_dbg(pps->dev, "PPS_SETPARAMS\n");
eae9d2ba RG	93
	94	/* Check the capabilities */
	95	if (!capable(CAP_SYS_TIME))
	96	return -EPERM;
	97
	98	err = copy_from_user(&params, uarg, sizeof(struct pps_kparams));
	99	if (err)
	100	return -EFAULT;
	101	if (!(params.mode & (PPS_CAPTUREASSERT \| PPS_CAPTURECLEAR))) {
7f7cce74	102	dev_dbg(pps->dev, "capture mode unspecified (%x)\n",
eae9d2ba RG	103	params.mode);
	104	return -EINVAL;
	105	}
	106
	107	/* Check for supported capabilities */
	108	if ((params.mode & ~pps->info.mode) != 0) {
7f7cce74	109	dev_dbg(pps->dev, "unsupported capabilities (%x)\n",
eae9d2ba RG	110	params.mode);
	111	return -EINVAL;
	112	}
	113
	114	spin_lock_irq(&pps->lock);
	115
	116	/* Save the new parameters */
	117	pps->params = params;
	118
	119	/* Restore the read only parameters */
	120	if ((params.mode & (PPS_TSFMT_TSPEC \| PPS_TSFMT_NTPFP)) == 0) {
	121	/* section 3.3 of RFC 2783 interpreted */
7f7cce74	122	dev_dbg(pps->dev, "time format unspecified (%x)\n",
eae9d2ba RG	123	params.mode);
	124	pps->params.mode \|= PPS_TSFMT_TSPEC;
	125	}
	126	if (pps->info.mode & PPS_CANWAIT)
	127	pps->params.mode \|= PPS_CANWAIT;
	128	pps->params.api_version = PPS_API_VERS;
	129
	130	spin_unlock_irq(&pps->lock);
	131
	132	break;
	133
	134	case PPS_GETCAP:
7f7cce74	135	dev_dbg(pps->dev, "PPS_GETCAP\n");
eae9d2ba RG	136
	137	err = put_user(pps->info.mode, iuarg);
	138	if (err)
	139	return -EFAULT;
	140
	141	break;
	142
86d921f9 AG	143	case PPS_FETCH: {
86d921f9 AG	144	struct pps_fdata fdata;
3003d55b	145	unsigned int ev;
86d921f9	146
7f7cce74	147	dev_dbg(pps->dev, "PPS_FETCH\n");
eae9d2ba RG	148
	149	err = copy_from_user(&fdata, uarg, sizeof(struct pps_fdata));
	150	if (err)
	151	return -EFAULT;
	152
3003d55b	153	ev = pps->last_ev;
eae9d2ba RG	154
	155	/* Manage the timeout */
	156	if (fdata.timeout.flags & PPS_TIME_INVALID)
3003d55b AG	157	err = wait_event_interruptible(pps->queue,
3003d55b AG	158	ev != pps->last_ev);
eae9d2ba	159	else {
86d921f9 AG	160	unsigned long ticks;
86d921f9 AG	161
7f7cce74	162	dev_dbg(pps->dev, "timeout %lld.%09d\n",
eae9d2ba RG	163	(long long) fdata.timeout.sec,
	164	fdata.timeout.nsec);
	165	ticks = fdata.timeout.sec * HZ;
	166	ticks += fdata.timeout.nsec / (NSEC_PER_SEC / HZ);
	167
	168	if (ticks != 0) {
	169	err = wait_event_interruptible_timeout(
3003d55b AG	170	pps->queue,
	171	ev != pps->last_ev,
	172	ticks);
eae9d2ba RG	173	if (err == 0)
	174	return -ETIMEDOUT;
	175	}
	176	}
	177
	178	/* Check for pending signals */
	179	if (err == -ERESTARTSYS) {
7f7cce74	180	dev_dbg(pps->dev, "pending signal caught\n");
eae9d2ba RG	181	return -EINTR;
	182	}
	183
	184	/* Return the fetched timestamp */
	185	spin_lock_irq(&pps->lock);
	186
	187	fdata.info.assert_sequence = pps->assert_sequence;
	188	fdata.info.clear_sequence = pps->clear_sequence;
	189	fdata.info.assert_tu = pps->assert_tu;
	190	fdata.info.clear_tu = pps->clear_tu;
	191	fdata.info.current_mode = pps->current_mode;
	192
	193	spin_unlock_irq(&pps->lock);
	194
	195	err = copy_to_user(uarg, &fdata, sizeof(struct pps_fdata));
	196	if (err)
	197	return -EFAULT;
	198
	199	break;
86d921f9	200	}
eae9d2ba RG	201	default:
	202	return -ENOTTY;
	203	break;
	204	}
	205
	206	return 0;
	207	}
	208
	209	static int pps_cdev_open(struct inode inode, struct file file)
	210	{
	211	struct pps_device *pps = container_of(inode->i_cdev,
	212	struct pps_device, cdev);
eae9d2ba RG	213	file->private_data = pps;
	214
	215	return 0;
	216	}
	217
	218	static int pps_cdev_release(struct inode inode, struct file file)
	219	{
eae9d2ba RG	220	return 0;
	221	}
	222
	223	/*
	224	* Char device stuff
	225	*/
	226
	227	static const struct file_operations pps_cdev_fops = {
	228	.owner = THIS_MODULE,
	229	.llseek = no_llseek,
	230	.poll = pps_cdev_poll,
	231	.fasync = pps_cdev_fasync,
	232	.unlocked_ioctl = pps_cdev_ioctl,
	233	.open = pps_cdev_open,
	234	.release = pps_cdev_release,
	235	};
	236
083e5866 AG	237	static void pps_device_destruct(struct device *dev)
	238	{
	239	struct pps_device *pps = dev_get_drvdata(dev);
	240
	241	/* release id here to protect others from using it while it's
	242	* still in use */
2a5cd6e2	243	mutex_lock(&pps_idr_lock);
083e5866	244	idr_remove(&pps_idr, pps->id);
2a5cd6e2	245	mutex_unlock(&pps_idr_lock);
083e5866 AG	246
	247	kfree(dev);
	248	kfree(pps);
	249	}
	250
eae9d2ba RG	251	int pps_register_cdev(struct pps_device *pps)
	252	{
	253	int err;
5e196d34 AG	254	dev_t devt;
5e196d34 AG	255
2a5cd6e2	256	mutex_lock(&pps_idr_lock);
083e5866	257	/* Get new ID for the new PPS source */
2a5cd6e2 AG	258	if (idr_pre_get(&pps_idr, GFP_KERNEL) == 0) {
2a5cd6e2 AG	259	mutex_unlock(&pps_idr_lock);
083e5866	260	return -ENOMEM;
2a5cd6e2	261	}
083e5866 AG	262
	263	/* Now really allocate the PPS source.
	264	* After idr_get_new() calling the new source will be freely available
	265	* into the kernel.
	266	*/
083e5866	267	err = idr_get_new(&pps_idr, pps, &pps->id);
2a5cd6e2	268	mutex_unlock(&pps_idr_lock);
083e5866 AG	269
	270	if (err < 0)
	271	return err;
	272
	273	pps->id &= MAX_ID_MASK;
	274	if (pps->id >= PPS_MAX_SOURCES) {
	275	pr_err("%s: too many PPS sources in the system\n",
	276	pps->info.name);
	277	err = -EBUSY;
	278	goto free_idr;
	279	}
	280
5e196d34	281	devt = MKDEV(MAJOR(pps_devt), pps->id);
eae9d2ba	282
eae9d2ba RG	283	cdev_init(&pps->cdev, &pps_cdev_fops);
	284	pps->cdev.owner = pps->info.owner;
	285
5e196d34	286	err = cdev_add(&pps->cdev, devt, 1);
eae9d2ba	287	if (err) {
7f7cce74	288	pr_err("%s: failed to add char device %d:%d\n",
eae9d2ba	289	pps->info.name, MAJOR(pps_devt), pps->id);
083e5866	290	goto free_idr;
eae9d2ba	291	}
5e196d34	292	pps->dev = device_create(pps_class, pps->info.dev, devt, pps,
eae9d2ba	293	"pps%d", pps->id);
054b2b13	294	if (IS_ERR(pps->dev))
eae9d2ba	295	goto del_cdev;
eae9d2ba	296
083e5866 AG	297	pps->dev->release = pps_device_destruct;
083e5866 AG	298
eae9d2ba RG	299	pr_debug("source %s got cdev (%d:%d)\n", pps->info.name,
	300	MAJOR(pps_devt), pps->id);
	301
	302	return 0;
	303
	304	del_cdev:
	305	cdev_del(&pps->cdev);
	306
083e5866	307	free_idr:
2a5cd6e2	308	mutex_lock(&pps_idr_lock);
083e5866	309	idr_remove(&pps_idr, pps->id);
2a5cd6e2	310	mutex_unlock(&pps_idr_lock);
083e5866	311
eae9d2ba RG	312	return err;
	313	}
	314
	315	void pps_unregister_cdev(struct pps_device *pps)
	316	{
5e196d34	317	device_destroy(pps_class, pps->dev->devt);
eae9d2ba RG	318	cdev_del(&pps->cdev);
	319	}
	320
	321	/*
	322	* Module stuff
	323	*/
	324
	325	static void __exit pps_exit(void)
	326	{
	327	class_destroy(pps_class);
	328	unregister_chrdev_region(pps_devt, PPS_MAX_SOURCES);
	329	}
	330
	331	static int __init pps_init(void)
	332	{
	333	int err;
	334
	335	pps_class = class_create(THIS_MODULE, "pps");
	336	if (!pps_class) {
7f7cce74	337	pr_err("failed to allocate class\n");
eae9d2ba RG	338	return -ENOMEM;
	339	}
	340	pps_class->dev_attrs = pps_attrs;
	341
	342	err = alloc_chrdev_region(&pps_devt, 0, PPS_MAX_SOURCES, "pps");
	343	if (err < 0) {
7f7cce74	344	pr_err("failed to allocate char device region\n");
eae9d2ba RG	345	goto remove_class;
	346	}
	347
	348	pr_info("LinuxPPS API ver. %d registered\n", PPS_API_VERS);
	349	pr_info("Software ver. %s - Copyright 2005-2007 Rodolfo Giometti "
	350	"<giometti@linux.it>\n", PPS_VERSION);
	351
	352	return 0;
	353
	354	remove_class:
	355	class_destroy(pps_class);
	356
	357	return err;
	358	}
	359
	360	subsys_initcall(pps_init);
	361	module_exit(pps_exit);
	362
	363	MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
	364	MODULE_DESCRIPTION("LinuxPPS support (RFC 2783) - ver. " PPS_VERSION);
	365	MODULE_LICENSE("GPL");