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

/*
 * kernel API
 *
 *
 * 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.
 */


#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/time.h>
#include <linux/spinlock.h>
#include <linux/idr.h>
#include <linux/fs.h>
#include <linux/pps_kernel.h>
#include <linux/slab.h>

/*
 * Local variables
 */

static DEFINE_SPINLOCK(pps_idr_lock);
static DEFINE_IDR(pps_idr);

/*
 * Local functions
 */

static void pps_add_offset(struct pps_ktime *ts, struct pps_ktime *offset)
{
	ts->nsec += offset->nsec;
	while (ts->nsec >= NSEC_PER_SEC) {
		ts->nsec -= NSEC_PER_SEC;
		ts->sec++;
	}
	while (ts->nsec < 0) {
		ts->nsec += NSEC_PER_SEC;
		ts->sec--;
	}
	ts->sec += offset->sec;
}

/*
 * Exported functions
 */

/* pps_register_source - add a PPS source in the system
 * @info: the PPS info struct
 * @default_params: the default PPS parameters of the new source
 *
 * This function is used to add a new PPS source in the system. The new
 * source is described by info's fields and it will have, as default PPS
 * parameters, the ones specified into default_params.
 *
 * The function returns, in case of success, the PPS device. Otherwise NULL.
 */

struct pps_device *pps_register_source(struct pps_source_info *info,
		int default_params)
{
	struct pps_device *pps;
	int id;
	int err;

	/* Sanity checks */
	if ((info->mode & default_params) != default_params) {
		printk(KERN_ERR "pps: %s: unsupported default parameters\n",
					info->name);
		err = -EINVAL;
		goto pps_register_source_exit;
	}
	if ((info->mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)) != 0 &&
			info->echo == NULL) {
		printk(KERN_ERR "pps: %s: echo function is not defined\n",
					info->name);
		err = -EINVAL;
		goto pps_register_source_exit;
	}
	if ((info->mode & (PPS_TSFMT_TSPEC | PPS_TSFMT_NTPFP)) == 0) {
		printk(KERN_ERR "pps: %s: unspecified time format\n",
					info->name);
		err = -EINVAL;
		goto pps_register_source_exit;
	}

	/* Allocate memory for the new PPS source struct */
	pps = kzalloc(sizeof(struct pps_device), GFP_KERNEL);
	if (pps == NULL) {
		err = -ENOMEM;
		goto pps_register_source_exit;
	}

	/* These initializations must be done before calling idr_get_new()
	 * in order to avoid reces into pps_event().
	 */
	pps->params.api_version = PPS_API_VERS;
	pps->params.mode = default_params;
	pps->info = *info;

	init_waitqueue_head(&pps->queue);
	spin_lock_init(&pps->lock);

	/* Get new ID for the new PPS source */
	if (idr_pre_get(&pps_idr, GFP_KERNEL) == 0) {
		err = -ENOMEM;
		goto kfree_pps;
	}

	spin_lock_irq(&pps_idr_lock);

	/* 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, &id);
	if (err < 0) {
		spin_unlock_irq(&pps_idr_lock);
		goto kfree_pps;
	}

	id = id & MAX_ID_MASK;
	if (id >= PPS_MAX_SOURCES) {
		spin_unlock_irq(&pps_idr_lock);

		printk(KERN_ERR "pps: %s: too many PPS sources in the system\n",
					info->name);
		err = -EBUSY;
		goto free_idr;
	}
	pps->id = id;

	spin_unlock_irq(&pps_idr_lock);

	/* Create the char device */
	err = pps_register_cdev(pps);
	if (err < 0) {
		printk(KERN_ERR "pps: %s: unable to create char device\n",
					info->name);
		goto free_idr;
	}

	pr_info("new PPS source %s at ID %d\n", info->name, id);

	return pps;

free_idr:
	spin_lock_irq(&pps_idr_lock);
	idr_remove(&pps_idr, id);
	spin_unlock_irq(&pps_idr_lock);

kfree_pps:
	kfree(pps);

pps_register_source_exit:
	printk(KERN_ERR "pps: %s: unable to register source\n", info->name);

	return NULL;
}
EXPORT_SYMBOL(pps_register_source);

/* pps_unregister_source - remove a PPS source from the system
 * @pps: the PPS source
 *
 * This function is used to remove a previously registered PPS source from
 * the system.
 */

void pps_unregister_source(struct pps_device *pps)
{
	unsigned int id = pps->id;

	pps_unregister_cdev(pps);

	spin_lock_irq(&pps_idr_lock);
	idr_remove(&pps_idr, pps->id);
	spin_unlock_irq(&pps_idr_lock);

	kfree(pps);
}
EXPORT_SYMBOL(pps_unregister_source);

/* pps_event - register a PPS event into the system
 * @pps: the PPS device
 * @ts: the event timestamp
 * @event: the event type
 * @data: userdef pointer
 *
 * This function is used by each PPS client in order to register a new
 * PPS event into the system (it's usually called inside an IRQ handler).
 *
 * If an echo function is associated with the PPS device it will be called
 * as:
 *	pps->info.echo(pps, event, data);
 */
void pps_event(struct pps_device *pps, struct pps_event_time *ts, int event,
		void *data)
{
	unsigned long flags;
	int captured = 0;
	struct pps_ktime ts_real;

	if ((event & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR)) == 0) {
		dev_err(pps->dev, "unknown event (%x)\n", event);
		return;
	}

	dev_dbg(pps->dev, "PPS event at %ld.%09ld\n",
			ts->ts_real.tv_sec, ts->ts_real.tv_nsec);

	timespec_to_pps_ktime(&ts_real, ts->ts_real);

	spin_lock_irqsave(&pps->lock, flags);

	/* Must call the echo function? */
	if ((pps->params.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)))
		pps->info.echo(pps, event, data);

	/* Check the event */
	pps->current_mode = pps->params.mode;
	if ((event & PPS_CAPTUREASSERT) &
			(pps->params.mode & PPS_CAPTUREASSERT)) {
		/* We have to add an offset? */
		if (pps->params.mode & PPS_OFFSETASSERT)
			pps_add_offset(&ts_real,
					&pps->params.assert_off_tu);

		/* Save the time stamp */
		pps->assert_tu = ts_real;
		pps->assert_sequence++;
		dev_dbg(pps->dev, "capture assert seq #%u\n",
			pps->assert_sequence);

		captured = ~0;
	}
	if ((event & PPS_CAPTURECLEAR) &
			(pps->params.mode & PPS_CAPTURECLEAR)) {
		/* We have to add an offset? */
		if (pps->params.mode & PPS_OFFSETCLEAR)
			pps_add_offset(&ts_real,
					&pps->params.clear_off_tu);

		/* Save the time stamp */
		pps->clear_tu = ts_real;
		pps->clear_sequence++;
		dev_dbg(pps->dev, "capture clear seq #%u\n",
			pps->clear_sequence);

		captured = ~0;
	}

	/* Wake up if captured something */
	if (captured) {
		pps->last_ev++;
		wake_up_interruptible_all(&pps->queue);

		kill_fasync(&pps->async_queue, SIGIO, POLL_IN);
	}

	spin_unlock_irqrestore(&pps->lock, flags);
}
EXPORT_SYMBOL(pps_event);
Commit	Line	Data
eae9d2ba RG	1	/*
	2	* kernel API
	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
	22
	23	#include <linux/kernel.h>
	24	#include <linux/module.h>
	25	#include <linux/init.h>
	26	#include <linux/sched.h>
	27	#include <linux/time.h>
	28	#include <linux/spinlock.h>
	29	#include <linux/idr.h>
	30	#include <linux/fs.h>
	31	#include <linux/pps_kernel.h>
5a0e3ad6	32	#include <linux/slab.h>
eae9d2ba RG	33
eae9d2ba RG	34	/*
5e196d34	35	* Local variables
eae9d2ba RG	36	*/
eae9d2ba RG	37
5e196d34 AG	38	static DEFINE_SPINLOCK(pps_idr_lock);
5e196d34 AG	39	static DEFINE_IDR(pps_idr);
eae9d2ba RG	40
	41	/*
	42	* Local functions
	43	*/
	44
	45	static void pps_add_offset(struct pps_ktime ts, struct pps_ktime offset)
	46	{
	47	ts->nsec += offset->nsec;
	48	while (ts->nsec >= NSEC_PER_SEC) {
	49	ts->nsec -= NSEC_PER_SEC;
	50	ts->sec++;
	51	}
	52	while (ts->nsec < 0) {
	53	ts->nsec += NSEC_PER_SEC;
	54	ts->sec--;
	55	}
	56	ts->sec += offset->sec;
	57	}
	58
	59	/*
	60	* Exported functions
	61	*/
	62
eae9d2ba RG	63	/* pps_register_source - add a PPS source in the system
	64	* @info: the PPS info struct
	65	* @default_params: the default PPS parameters of the new source
	66	*
	67	* This function is used to add a new PPS source in the system. The new
	68	* source is described by info's fields and it will have, as default PPS
	69	* parameters, the ones specified into default_params.
	70	*
5e196d34	71	* The function returns, in case of success, the PPS device. Otherwise NULL.
eae9d2ba RG	72	*/
eae9d2ba RG	73
5e196d34 AG	74	struct pps_device pps_register_source(struct pps_source_info info,
5e196d34 AG	75	int default_params)
eae9d2ba RG	76	{
	77	struct pps_device *pps;
	78	int id;
	79	int err;
	80
	81	/* Sanity checks */
	82	if ((info->mode & default_params) != default_params) {
	83	printk(KERN_ERR "pps: %s: unsupported default parameters\n",
	84	info->name);
	85	err = -EINVAL;
	86	goto pps_register_source_exit;
	87	}
	88	if ((info->mode & (PPS_ECHOASSERT \| PPS_ECHOCLEAR)) != 0 &&
	89	info->echo == NULL) {
	90	printk(KERN_ERR "pps: %s: echo function is not defined\n",
	91	info->name);
	92	err = -EINVAL;
	93	goto pps_register_source_exit;
	94	}
	95	if ((info->mode & (PPS_TSFMT_TSPEC \| PPS_TSFMT_NTPFP)) == 0) {
	96	printk(KERN_ERR "pps: %s: unspecified time format\n",
	97	info->name);
	98	err = -EINVAL;
	99	goto pps_register_source_exit;
	100	}
	101
	102	/* Allocate memory for the new PPS source struct */
	103	pps = kzalloc(sizeof(struct pps_device), GFP_KERNEL);
	104	if (pps == NULL) {
	105	err = -ENOMEM;
	106	goto pps_register_source_exit;
	107	}
	108
	109	/* These initializations must be done before calling idr_get_new()
	110	* in order to avoid reces into pps_event().
	111	*/
	112	pps->params.api_version = PPS_API_VERS;
	113	pps->params.mode = default_params;
	114	pps->info = *info;
	115
	116	init_waitqueue_head(&pps->queue);
	117	spin_lock_init(&pps->lock);
eae9d2ba RG	118
	119	/* Get new ID for the new PPS source */
	120	if (idr_pre_get(&pps_idr, GFP_KERNEL) == 0) {
	121	err = -ENOMEM;
	122	goto kfree_pps;
	123	}
	124
	125	spin_lock_irq(&pps_idr_lock);
	126
	127	/* Now really allocate the PPS source.
	128	* After idr_get_new() calling the new source will be freely available
	129	* into the kernel.
	130	*/
	131	err = idr_get_new(&pps_idr, pps, &id);
	132	if (err < 0) {
	133	spin_unlock_irq(&pps_idr_lock);
	134	goto kfree_pps;
	135	}
	136
	137	id = id & MAX_ID_MASK;
	138	if (id >= PPS_MAX_SOURCES) {
	139	spin_unlock_irq(&pps_idr_lock);
	140
	141	printk(KERN_ERR "pps: %s: too many PPS sources in the system\n",
	142	info->name);
	143	err = -EBUSY;
	144	goto free_idr;
	145	}
	146	pps->id = id;
	147
	148	spin_unlock_irq(&pps_idr_lock);
	149
	150	/* Create the char device */
	151	err = pps_register_cdev(pps);
	152	if (err < 0) {
	153	printk(KERN_ERR "pps: %s: unable to create char device\n",
	154	info->name);
	155	goto free_idr;
	156	}
	157
	158	pr_info("new PPS source %s at ID %d\n", info->name, id);
	159
5e196d34	160	return pps;
eae9d2ba RG	161
	162	free_idr:
	163	spin_lock_irq(&pps_idr_lock);
	164	idr_remove(&pps_idr, id);
	165	spin_unlock_irq(&pps_idr_lock);
	166
	167	kfree_pps:
	168	kfree(pps);
	169
	170	pps_register_source_exit:
	171	printk(KERN_ERR "pps: %s: unable to register source\n", info->name);
	172
5e196d34	173	return NULL;
eae9d2ba RG	174	}
	175	EXPORT_SYMBOL(pps_register_source);
	176
	177	/* pps_unregister_source - remove a PPS source from the system
5e196d34	178	* @pps: the PPS source
eae9d2ba RG	179	*
	180	* This function is used to remove a previously registered PPS source from
	181	* the system.
	182	*/
	183
5e196d34	184	void pps_unregister_source(struct pps_device *pps)
eae9d2ba	185	{
5e196d34	186	unsigned int id = pps->id;
eae9d2ba	187
5e196d34	188	pps_unregister_cdev(pps);
eae9d2ba	189
5e196d34 AG	190	spin_lock_irq(&pps_idr_lock);
5e196d34 AG	191	idr_remove(&pps_idr, pps->id);
eae9d2ba RG	192	spin_unlock_irq(&pps_idr_lock);
eae9d2ba RG	193
5e196d34	194	kfree(pps);
eae9d2ba RG	195	}
	196	EXPORT_SYMBOL(pps_unregister_source);
	197
	198	/* pps_event - register a PPS event into the system
5e196d34	199	* @pps: the PPS device
eae9d2ba RG	200	* @ts: the event timestamp
	201	* @event: the event type
	202	* @data: userdef pointer
	203	*
	204	* This function is used by each PPS client in order to register a new
	205	* PPS event into the system (it's usually called inside an IRQ handler).
	206	*
5e196d34	207	* If an echo function is associated with the PPS device it will be called
eae9d2ba	208	* as:
5e196d34	209	* pps->info.echo(pps, event, data);
eae9d2ba	210	*/
5e196d34 AG	211	void pps_event(struct pps_device pps, struct pps_event_time ts, int event,
5e196d34 AG	212	void *data)
eae9d2ba	213	{
eae9d2ba	214	unsigned long flags;
276b282e	215	int captured = 0;
6f4229b5	216	struct pps_ktime ts_real;
eae9d2ba RG	217
eae9d2ba RG	218	if ((event & (PPS_CAPTUREASSERT \| PPS_CAPTURECLEAR)) == 0) {
5e196d34	219	dev_err(pps->dev, "unknown event (%x)\n", event);
eae9d2ba RG	220	return;
	221	}
	222
5e196d34 AG	223	dev_dbg(pps->dev, "PPS event at %ld.%09ld\n",
5e196d34 AG	224	ts->ts_real.tv_sec, ts->ts_real.tv_nsec);
6f4229b5 AG	225
6f4229b5 AG	226	timespec_to_pps_ktime(&ts_real, ts->ts_real);
eae9d2ba RG	227
	228	spin_lock_irqsave(&pps->lock, flags);
	229
	230	/* Must call the echo function? */
	231	if ((pps->params.mode & (PPS_ECHOASSERT \| PPS_ECHOCLEAR)))
5e196d34	232	pps->info.echo(pps, event, data);
eae9d2ba RG	233
	234	/* Check the event */
	235	pps->current_mode = pps->params.mode;
276b282e RG	236	if ((event & PPS_CAPTUREASSERT) &
276b282e RG	237	(pps->params.mode & PPS_CAPTUREASSERT)) {
eae9d2ba RG	238	/* We have to add an offset? */
eae9d2ba RG	239	if (pps->params.mode & PPS_OFFSETASSERT)
6f4229b5 AG	240	pps_add_offset(&ts_real,
6f4229b5 AG	241	&pps->params.assert_off_tu);
eae9d2ba RG	242
eae9d2ba RG	243	/* Save the time stamp */
6f4229b5	244	pps->assert_tu = ts_real;
eae9d2ba	245	pps->assert_sequence++;
5e196d34 AG	246	dev_dbg(pps->dev, "capture assert seq #%u\n",
5e196d34 AG	247	pps->assert_sequence);
276b282e RG	248
276b282e RG	249	captured = ~0;
eae9d2ba	250	}
276b282e RG	251	if ((event & PPS_CAPTURECLEAR) &
276b282e RG	252	(pps->params.mode & PPS_CAPTURECLEAR)) {
eae9d2ba RG	253	/* We have to add an offset? */
eae9d2ba RG	254	if (pps->params.mode & PPS_OFFSETCLEAR)
6f4229b5 AG	255	pps_add_offset(&ts_real,
6f4229b5 AG	256	&pps->params.clear_off_tu);
eae9d2ba RG	257
eae9d2ba RG	258	/* Save the time stamp */
6f4229b5	259	pps->clear_tu = ts_real;
eae9d2ba	260	pps->clear_sequence++;
5e196d34 AG	261	dev_dbg(pps->dev, "capture clear seq #%u\n",
5e196d34 AG	262	pps->clear_sequence);
276b282e RG	263
276b282e RG	264	captured = ~0;
eae9d2ba RG	265	}
eae9d2ba RG	266
7a21a3cc	267	/* Wake up if captured something */
276b282e	268	if (captured) {
3003d55b AG	269	pps->last_ev++;
3003d55b AG	270	wake_up_interruptible_all(&pps->queue);
eae9d2ba	271
276b282e RG	272	kill_fasync(&pps->async_queue, SIGIO, POLL_IN);
276b282e RG	273	}
eae9d2ba RG	274
eae9d2ba RG	275	spin_unlock_irqrestore(&pps->lock, flags);
eae9d2ba RG	276	}
eae9d2ba RG	277	EXPORT_SYMBOL(pps_event);