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pps: access pps device by direct pointer

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Using device index as a pointer needs some unnecessary work to be done
every time the pointer is needed (in irq handler for example).  Using a
direct pointer is much more easy (and safe as well).

Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su>
Acked-by: Rodolfo Giometti <giometti@linux.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Alexander Gordeev
2011-01-12 17:00:51 -08:00
committed by Linus Torvalds
parent 6f4229b511
commit 5e196d34a7
5 changed files with 85 additions and 161 deletions
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128
drivers/pps/kapi.c
View File

@@ -32,11 +32,11 @@
#include <linux/slab.h>
/*
* Global variables
* Local variables
*/
DEFINE_SPINLOCK(pps_idr_lock);
DEFINE_IDR(pps_idr);
static DEFINE_SPINLOCK(pps_idr_lock);
static DEFINE_IDR(pps_idr);
/*
* Local functions
@@ -60,60 +60,6 @@ static void pps_add_offset(struct pps_ktime *ts, struct pps_ktime *offset)
* 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
@@ -122,10 +68,11 @@ exit:
* 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.
* The function returns, in case of success, the PPS device. Otherwise NULL.
*/
int pps_register_source(struct pps_source_info *info, int default_params)
struct pps_device *pps_register_source(struct pps_source_info *info,
int default_params)
{
struct pps_device *pps;
int id;
@@ -168,7 +115,6 @@ int pps_register_source(struct pps_source_info *info, int default_params)
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) {
@@ -211,7 +157,7 @@ int pps_register_source(struct pps_source_info *info, int default_params)
pr_info("new PPS source %s at ID %d\n", info->name, id);
return id;
return pps;
free_idr:
spin_lock_irq(&pps_idr_lock);
@@ -224,38 +170,33 @@ kfree_pps:
pps_register_source_exit:
printk(KERN_ERR "pps: %s: unable to register source\n", info->name);
return err;
return NULL;
}
EXPORT_SYMBOL(pps_register_source);
/* pps_unregister_source - remove a PPS source from the system
* @source: the PPS source ID
* @pps: the PPS source
*
* This function is used to remove a previously registered PPS source from
* the system.
*/
void pps_unregister_source(int source)
void pps_unregister_source(struct pps_device *pps)
{
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);
unsigned int id = pps->id;
pps_unregister_cdev(pps);
pps_put_source(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
* @source: the PPS source ID
* @pps: the PPS device
* @ts: the event timestamp
* @event: the event type
* @data: userdef pointer
@@ -263,30 +204,24 @@ EXPORT_SYMBOL(pps_unregister_source);
* 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
* If an echo function is associated with the PPS device it will be called
* as:
* pps->info.echo(source, event, data);
* pps->info.echo(pps, event, data);
*/
void pps_event(int source, struct pps_event_time *ts, int event, void *data)
void pps_event(struct pps_device *pps, struct pps_event_time *ts, int event,
void *data)
{
struct pps_device *pps;
unsigned long flags;
int captured = 0;
struct pps_ktime ts_real;
if ((event & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR)) == 0) {
printk(KERN_ERR "pps: unknown event (%x) for source %d\n",
event, source);
dev_err(pps->dev, "unknown event (%x)\n", event);
return;
}
pps = pps_get_source(source);
if (!pps)
return;
pr_debug("PPS event on source %d at %ld.%09ld\n",
pps->id, ts->ts_real.tv_sec, ts->ts_real.tv_nsec);
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);
@@ -294,7 +229,7 @@ void pps_event(int source, struct pps_event_time *ts, int event, void *data)
/* Must call the echo function? */
if ((pps->params.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)))
pps->info.echo(source, event, data);
pps->info.echo(pps, event, data);
/* Check the event */
pps->current_mode = pps->params.mode;
@@ -308,8 +243,8 @@ void pps_event(int source, struct pps_event_time *ts, int event, void *data)
/* Save the time stamp */
pps->assert_tu = ts_real;
pps->assert_sequence++;
pr_debug("capture assert seq #%u for source %d\n",
pps->assert_sequence, source);
dev_dbg(pps->dev, "capture assert seq #%u\n",
pps->assert_sequence);
captured = ~0;
}
@@ -323,8 +258,8 @@ void pps_event(int source, struct pps_event_time *ts, int event, void *data)
/* Save the time stamp */
pps->clear_tu = ts_real;
pps->clear_sequence++;
pr_debug("capture clear seq #%u for source %d\n",
pps->clear_sequence, source);
dev_dbg(pps->dev, "capture clear seq #%u\n",
pps->clear_sequence);
captured = ~0;
}
@@ -338,8 +273,5 @@ void pps_event(int source, struct pps_event_time *ts, int event, void *data)
}
spin_unlock_irqrestore(&pps->lock, flags);
/* Now we can release the PPS source for (possible) deregistration */
pps_put_source(pps);
}
EXPORT_SYMBOL(pps_event);