linux/drivers/pps/kapi.c

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/*
* 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 cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 08:04:11 +00:00
#include <linux/slab.h>
/*
* Global variables
*/
DEFINE_SPINLOCK(pps_idr_lock);
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_get_source - find a PPS source
* @source: the PPS source ID.
*
* This function is used to find an already registered PPS source into the
* system.
*
* The function returns NULL if found nothing, otherwise it returns a pointer
* to the PPS source data struct (the refcounter is incremented by 1).
*/
struct pps_device *pps_get_source(int source)
{
struct pps_device *pps;
unsigned long flags;
spin_lock_irqsave(&pps_idr_lock, flags);
pps = idr_find(&pps_idr, source);
if (pps != NULL)
atomic_inc(&pps->usage);
spin_unlock_irqrestore(&pps_idr_lock, flags);
return pps;
}
/* pps_put_source - free the PPS source data
* @pps: a pointer to the PPS source.
*
* This function is used to free a PPS data struct if its refcount is 0.
*/
void pps_put_source(struct pps_device *pps)
{
unsigned long flags;
spin_lock_irqsave(&pps_idr_lock, flags);
BUG_ON(atomic_read(&pps->usage) == 0);
if (!atomic_dec_and_test(&pps->usage)) {
pps = NULL;
goto exit;
}
/* No more reference to the PPS source. We can safely remove the
* PPS data struct.
*/
idr_remove(&pps_idr, pps->id);
exit:
spin_unlock_irqrestore(&pps_idr_lock, flags);
kfree(pps);
}
/* 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 source ID.
*/
int 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);
atomic_set(&pps->usage, 1);
/* 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 id;
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 err;
}
EXPORT_SYMBOL(pps_register_source);
/* pps_unregister_source - remove a PPS source from the system
* @source: the PPS source ID
*
* This function is used to remove a previously registered PPS source from
* the system.
*/
void pps_unregister_source(int source)
{
struct pps_device *pps;
spin_lock_irq(&pps_idr_lock);
pps = idr_find(&pps_idr, source);
if (!pps) {
BUG();
spin_unlock_irq(&pps_idr_lock);
return;
}
spin_unlock_irq(&pps_idr_lock);
pps_unregister_cdev(pps);
pps_put_source(pps);
}
EXPORT_SYMBOL(pps_unregister_source);
/* pps_event - register a PPS event into the system
* @source: the PPS source ID
* @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 source it will be called
* as:
* pps->info.echo(source, event, data);
*/
void pps_event(int source, struct pps_ktime *ts, int event, void *data)
{
struct pps_device *pps;
unsigned long flags;
int captured = 0;
if ((event & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR)) == 0) {
printk(KERN_ERR "pps: unknown event (%x) for source %d\n",
event, source);
return;
}
pps = pps_get_source(source);
if (!pps)
return;
pr_debug("PPS event on source %d at %llu.%06u\n",
pps->id, (unsigned long long) ts->sec, ts->nsec);
spin_lock_irqsave(&pps->lock, flags);
/* Must call the echo function? */
if ((pps->params.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)))
pps->info.echo(source, 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, &pps->params.assert_off_tu);
/* Save the time stamp */
pps->assert_tu = *ts;
pps->assert_sequence++;
pr_debug("capture assert seq #%u for source %d\n",
pps->assert_sequence, source);
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, &pps->params.clear_off_tu);
/* Save the time stamp */
pps->clear_tu = *ts;
pps->clear_sequence++;
pr_debug("capture clear seq #%u for source %d\n",
pps->clear_sequence, source);
captured = ~0;
}
/* Wake up iif captured somthing */
if (captured) {
pps->go = ~0;
wake_up_interruptible(&pps->queue);
kill_fasync(&pps->async_queue, SIGIO, POLL_IN);
}
spin_unlock_irqrestore(&pps->lock, flags);
/* Now we can release the PPS source for (possible) deregistration */
pps_put_source(pps);
}
EXPORT_SYMBOL(pps_event);