[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.
 */

#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/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) {
		pr_err("%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) {
		pr_err("%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) {
		pr_err("%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);

		pr_err("%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) {
		pr_err("%s: unable to create char device\n",
					info->name);
		goto free_idr;
	}

	dev_info(pps->dev, "new PPS source %s\n", info->name);

	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:
	pr_err("%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
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/time.h>
	29	#include <linux/spinlock.h>
	30	#include <linux/idr.h>
	31	#include <linux/fs.h>
	32	#include <linux/pps_kernel.h>
5a0e3ad6	33	#include <linux/slab.h>
eae9d2ba RG	34
eae9d2ba RG	35	/*
5e196d34	36	* Local variables
eae9d2ba RG	37	*/
eae9d2ba RG	38
5e196d34 AG	39	static DEFINE_SPINLOCK(pps_idr_lock);
5e196d34 AG	40	static DEFINE_IDR(pps_idr);
eae9d2ba RG	41
	42	/*
	43	* Local functions
	44	*/
	45
	46	static void pps_add_offset(struct pps_ktime ts, struct pps_ktime offset)
	47	{
	48	ts->nsec += offset->nsec;
	49	while (ts->nsec >= NSEC_PER_SEC) {
	50	ts->nsec -= NSEC_PER_SEC;
	51	ts->sec++;
	52	}
	53	while (ts->nsec < 0) {
	54	ts->nsec += NSEC_PER_SEC;
	55	ts->sec--;
	56	}
	57	ts->sec += offset->sec;
	58	}
	59
	60	/*
	61	* Exported functions
	62	*/
	63
eae9d2ba RG	64	/* pps_register_source - add a PPS source in the system
	65	* @info: the PPS info struct
	66	* @default_params: the default PPS parameters of the new source
	67	*
	68	* This function is used to add a new PPS source in the system. The new
	69	* source is described by info's fields and it will have, as default PPS
	70	* parameters, the ones specified into default_params.
	71	*
5e196d34	72	* The function returns, in case of success, the PPS device. Otherwise NULL.
eae9d2ba RG	73	*/
eae9d2ba RG	74
5e196d34 AG	75	struct pps_device pps_register_source(struct pps_source_info info,
5e196d34 AG	76	int default_params)
eae9d2ba RG	77	{
	78	struct pps_device *pps;
	79	int id;
	80	int err;
	81
	82	/* Sanity checks */
	83	if ((info->mode & default_params) != default_params) {
7f7cce74	84	pr_err("%s: unsupported default parameters\n",
eae9d2ba RG	85	info->name);
	86	err = -EINVAL;
	87	goto pps_register_source_exit;
	88	}
	89	if ((info->mode & (PPS_ECHOASSERT \| PPS_ECHOCLEAR)) != 0 &&
	90	info->echo == NULL) {
7f7cce74	91	pr_err("%s: echo function is not defined\n",
eae9d2ba RG	92	info->name);
	93	err = -EINVAL;
	94	goto pps_register_source_exit;
	95	}
	96	if ((info->mode & (PPS_TSFMT_TSPEC \| PPS_TSFMT_NTPFP)) == 0) {
7f7cce74	97	pr_err("%s: unspecified time format\n",
eae9d2ba RG	98	info->name);
	99	err = -EINVAL;
	100	goto pps_register_source_exit;
	101	}
	102
	103	/* Allocate memory for the new PPS source struct */
	104	pps = kzalloc(sizeof(struct pps_device), GFP_KERNEL);
	105	if (pps == NULL) {
	106	err = -ENOMEM;
	107	goto pps_register_source_exit;
	108	}
	109
	110	/* These initializations must be done before calling idr_get_new()
	111	* in order to avoid reces into pps_event().
	112	*/
	113	pps->params.api_version = PPS_API_VERS;
	114	pps->params.mode = default_params;
	115	pps->info = *info;
	116
	117	init_waitqueue_head(&pps->queue);
	118	spin_lock_init(&pps->lock);
eae9d2ba RG	119
	120	/* Get new ID for the new PPS source */
	121	if (idr_pre_get(&pps_idr, GFP_KERNEL) == 0) {
	122	err = -ENOMEM;
	123	goto kfree_pps;
	124	}
	125
	126	spin_lock_irq(&pps_idr_lock);
	127
	128	/* Now really allocate the PPS source.
	129	* After idr_get_new() calling the new source will be freely available
	130	* into the kernel.
	131	*/
	132	err = idr_get_new(&pps_idr, pps, &id);
	133	if (err < 0) {
	134	spin_unlock_irq(&pps_idr_lock);
	135	goto kfree_pps;
	136	}
	137
	138	id = id & MAX_ID_MASK;
	139	if (id >= PPS_MAX_SOURCES) {
	140	spin_unlock_irq(&pps_idr_lock);
	141
7f7cce74	142	pr_err("%s: too many PPS sources in the system\n",
eae9d2ba RG	143	info->name);
	144	err = -EBUSY;
	145	goto free_idr;
	146	}
	147	pps->id = id;
	148
	149	spin_unlock_irq(&pps_idr_lock);
	150
	151	/* Create the char device */
	152	err = pps_register_cdev(pps);
	153	if (err < 0) {
7f7cce74	154	pr_err("%s: unable to create char device\n",
eae9d2ba RG	155	info->name);
	156	goto free_idr;
	157	}
	158
7f7cce74	159	dev_info(pps->dev, "new PPS source %s\n", info->name);
eae9d2ba	160
5e196d34	161	return pps;
eae9d2ba RG	162
	163	free_idr:
	164	spin_lock_irq(&pps_idr_lock);
	165	idr_remove(&pps_idr, id);
	166	spin_unlock_irq(&pps_idr_lock);
	167
	168	kfree_pps:
	169	kfree(pps);
	170
	171	pps_register_source_exit:
7f7cce74	172	pr_err("%s: unable to register source\n", info->name);
eae9d2ba	173
5e196d34	174	return NULL;
eae9d2ba RG	175	}
	176	EXPORT_SYMBOL(pps_register_source);
	177
	178	/* pps_unregister_source - remove a PPS source from the system
5e196d34	179	* @pps: the PPS source
eae9d2ba RG	180	*
	181	* This function is used to remove a previously registered PPS source from
	182	* the system.
	183	*/
	184
5e196d34	185	void pps_unregister_source(struct pps_device *pps)
eae9d2ba	186	{
5e196d34	187	unsigned int id = pps->id;
eae9d2ba	188
5e196d34	189	pps_unregister_cdev(pps);
eae9d2ba	190
5e196d34 AG	191	spin_lock_irq(&pps_idr_lock);
5e196d34 AG	192	idr_remove(&pps_idr, pps->id);
eae9d2ba RG	193	spin_unlock_irq(&pps_idr_lock);
eae9d2ba RG	194
5e196d34	195	kfree(pps);
eae9d2ba RG	196	}
	197	EXPORT_SYMBOL(pps_unregister_source);
	198
	199	/* pps_event - register a PPS event into the system
5e196d34	200	* @pps: the PPS device
eae9d2ba RG	201	* @ts: the event timestamp
	202	* @event: the event type
	203	* @data: userdef pointer
	204	*
	205	* This function is used by each PPS client in order to register a new
	206	* PPS event into the system (it's usually called inside an IRQ handler).
	207	*
5e196d34	208	* If an echo function is associated with the PPS device it will be called
eae9d2ba	209	* as:
5e196d34	210	* pps->info.echo(pps, event, data);
eae9d2ba	211	*/
5e196d34 AG	212	void pps_event(struct pps_device pps, struct pps_event_time ts, int event,
5e196d34 AG	213	void *data)
eae9d2ba	214	{
eae9d2ba	215	unsigned long flags;
276b282e	216	int captured = 0;
6f4229b5	217	struct pps_ktime ts_real;
eae9d2ba RG	218
eae9d2ba RG	219	if ((event & (PPS_CAPTUREASSERT \| PPS_CAPTURECLEAR)) == 0) {
5e196d34	220	dev_err(pps->dev, "unknown event (%x)\n", event);
eae9d2ba RG	221	return;
	222	}
	223
5e196d34 AG	224	dev_dbg(pps->dev, "PPS event at %ld.%09ld\n",
5e196d34 AG	225	ts->ts_real.tv_sec, ts->ts_real.tv_nsec);
6f4229b5 AG	226
6f4229b5 AG	227	timespec_to_pps_ktime(&ts_real, ts->ts_real);
eae9d2ba RG	228
	229	spin_lock_irqsave(&pps->lock, flags);
	230
	231	/* Must call the echo function? */
	232	if ((pps->params.mode & (PPS_ECHOASSERT \| PPS_ECHOCLEAR)))
5e196d34	233	pps->info.echo(pps, event, data);
eae9d2ba RG	234
	235	/* Check the event */
	236	pps->current_mode = pps->params.mode;
276b282e RG	237	if ((event & PPS_CAPTUREASSERT) &
276b282e RG	238	(pps->params.mode & PPS_CAPTUREASSERT)) {
eae9d2ba RG	239	/* We have to add an offset? */
eae9d2ba RG	240	if (pps->params.mode & PPS_OFFSETASSERT)
6f4229b5 AG	241	pps_add_offset(&ts_real,
6f4229b5 AG	242	&pps->params.assert_off_tu);
eae9d2ba RG	243
eae9d2ba RG	244	/* Save the time stamp */
6f4229b5	245	pps->assert_tu = ts_real;
eae9d2ba	246	pps->assert_sequence++;
5e196d34 AG	247	dev_dbg(pps->dev, "capture assert seq #%u\n",
5e196d34 AG	248	pps->assert_sequence);
276b282e RG	249
276b282e RG	250	captured = ~0;
eae9d2ba	251	}
276b282e RG	252	if ((event & PPS_CAPTURECLEAR) &
276b282e RG	253	(pps->params.mode & PPS_CAPTURECLEAR)) {
eae9d2ba RG	254	/* We have to add an offset? */
eae9d2ba RG	255	if (pps->params.mode & PPS_OFFSETCLEAR)
6f4229b5 AG	256	pps_add_offset(&ts_real,
6f4229b5 AG	257	&pps->params.clear_off_tu);
eae9d2ba RG	258
eae9d2ba RG	259	/* Save the time stamp */
6f4229b5	260	pps->clear_tu = ts_real;
eae9d2ba	261	pps->clear_sequence++;
5e196d34 AG	262	dev_dbg(pps->dev, "capture clear seq #%u\n",
5e196d34 AG	263	pps->clear_sequence);
276b282e RG	264
276b282e RG	265	captured = ~0;
eae9d2ba RG	266	}
eae9d2ba RG	267
7a21a3cc	268	/* Wake up if captured something */
276b282e	269	if (captured) {
3003d55b AG	270	pps->last_ev++;
3003d55b AG	271	wake_up_interruptible_all(&pps->queue);
eae9d2ba	272
276b282e RG	273	kill_fasync(&pps->async_queue, SIGIO, POLL_IN);
276b282e RG	274	}
eae9d2ba RG	275
eae9d2ba RG	276	spin_unlock_irqrestore(&pps->lock, flags);
eae9d2ba RG	277	}
eae9d2ba RG	278	EXPORT_SYMBOL(pps_event);