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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 <[email protected]>
Acked-by: Rodolfo Giometti <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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@ago @torvalds
ago authored and torvalds committed Jan 13, 2011
1 parent 6f4229b commit 5e196d3
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Showing 5 changed files with 82 additions and 158 deletions.
30 changes: 13 additions & 17 deletions drivers/pps/clients/pps-ktimer.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -31,7 +31,7 @@
* Global variables
*/

static int source;
static struct pps_device *pps;
static struct timer_list ktimer;

/*
Expand All @@ -47,7 +47,7 @@ static void pps_ktimer_event(unsigned long ptr)

pr_info("PPS event at %lu\n", jiffies);

pps_event(source, &ts, PPS_CAPTUREASSERT, NULL);
pps_event(pps, &ts, PPS_CAPTUREASSERT, NULL);

mod_timer(&ktimer, jiffies + HZ);
}
Expand All @@ -56,12 +56,11 @@ static void pps_ktimer_event(unsigned long ptr)
* The echo function
*/

static void pps_ktimer_echo(int source, int event, void *data)
static void pps_ktimer_echo(struct pps_device *pps, int event, void *data)
{
pr_info("echo %s %s for source %d\n",
dev_info(pps->dev, "echo %s %s\n",
event & PPS_CAPTUREASSERT ? "assert" : "",
event & PPS_CAPTURECLEAR ? "clear" : "",
source);
event & PPS_CAPTURECLEAR ? "clear" : "");
}

/*
Expand All @@ -84,30 +83,27 @@ static struct pps_source_info pps_ktimer_info = {

static void __exit pps_ktimer_exit(void)
{
del_timer_sync(&ktimer);
pps_unregister_source(source);
dev_info(pps->dev, "ktimer PPS source unregistered\n");

pr_info("ktimer PPS source unregistered\n");
del_timer_sync(&ktimer);
pps_unregister_source(pps);
}

static int __init pps_ktimer_init(void)
{
int ret;

ret = pps_register_source(&pps_ktimer_info,
pps = pps_register_source(&pps_ktimer_info,
PPS_CAPTUREASSERT | PPS_OFFSETASSERT);
if (ret < 0) {
if (pps == NULL) {
printk(KERN_ERR "cannot register ktimer source\n");
return ret;
return -ENOMEM;
}
source = ret;

setup_timer(&ktimer, pps_ktimer_event, 0);
mod_timer(&ktimer, jiffies + HZ);

pr_info("ktimer PPS source registered at %d\n", source);
dev_info(pps->dev, "ktimer PPS source registered\n");

return 0;
return 0;
}

module_init(pps_ktimer_init);
Expand Down
41 changes: 26 additions & 15 deletions drivers/pps/clients/pps-ldisc.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -29,7 +29,7 @@
static void pps_tty_dcd_change(struct tty_struct *tty, unsigned int status,
struct pps_event_time *ts)
{
int id = (long)tty->disc_data;
struct pps_device *pps = (struct pps_device *)tty->disc_data;
struct pps_event_time __ts;

/* First of all we get the time stamp... */
Expand All @@ -39,12 +39,14 @@ static void pps_tty_dcd_change(struct tty_struct *tty, unsigned int status,
if (!ts) /* No. Do it ourself! */
ts = &__ts;

BUG_ON(pps == NULL);

/* Now do the PPS event report */
pps_event(id, ts, status ? PPS_CAPTUREASSERT : PPS_CAPTURECLEAR,
NULL);
pps_event(pps, ts, status ? PPS_CAPTUREASSERT :
PPS_CAPTURECLEAR, NULL);

pr_debug("PPS %s at %lu on source #%d\n",
status ? "assert" : "clear", jiffies, id);
dev_dbg(pps->dev, "PPS %s at %lu\n",
status ? "assert" : "clear", jiffies);
}

static int (*alias_n_tty_open)(struct tty_struct *tty);
Expand All @@ -54,6 +56,7 @@ static int pps_tty_open(struct tty_struct *tty)
struct pps_source_info info;
struct tty_driver *drv = tty->driver;
int index = tty->index + drv->name_base;
struct pps_device *pps;
int ret;

info.owner = THIS_MODULE;
Expand All @@ -64,34 +67,42 @@ static int pps_tty_open(struct tty_struct *tty)
PPS_OFFSETASSERT | PPS_OFFSETCLEAR | \
PPS_CANWAIT | PPS_TSFMT_TSPEC;

ret = pps_register_source(&info, PPS_CAPTUREBOTH | \
pps = pps_register_source(&info, PPS_CAPTUREBOTH | \
PPS_OFFSETASSERT | PPS_OFFSETCLEAR);
if (ret < 0) {
if (pps == NULL) {
pr_err("cannot register PPS source \"%s\"\n", info.path);
return ret;
return -ENOMEM;
}
tty->disc_data = (void *)(long)ret;
tty->disc_data = pps;

/* Should open N_TTY ldisc too */
ret = alias_n_tty_open(tty);
if (ret < 0)
pps_unregister_source((long)tty->disc_data);
if (ret < 0) {
pr_err("cannot open tty ldisc \"%s\"\n", info.path);
goto err_unregister;
}

pr_info("PPS source #%d \"%s\" added\n", ret, info.path);
dev_info(pps->dev, "source \"%s\" added\n", info.path);

return 0;

err_unregister:
tty->disc_data = NULL;
pps_unregister_source(pps);
return ret;
}

static void (*alias_n_tty_close)(struct tty_struct *tty);

static void pps_tty_close(struct tty_struct *tty)
{
int id = (long)tty->disc_data;
struct pps_device *pps = (struct pps_device *)tty->disc_data;

pps_unregister_source(id);
alias_n_tty_close(tty);

pr_info("PPS source #%d removed\n", id);
tty->disc_data = NULL;
dev_info(pps->dev, "removed\n");
pps_unregister_source(pps);
}

static struct tty_ldisc_ops pps_ldisc_ops;
Expand Down
124 changes: 28 additions & 96 deletions drivers/pps/kapi.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand All @@ -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
Expand All @@ -122,10 +68,11 @@ void pps_put_source(struct pps_device *pps)
* 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;
Expand Down Expand Up @@ -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) {
Expand Down Expand Up @@ -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);
Expand All @@ -224,77 +170,66 @@ int pps_register_source(struct pps_source_info *info, int default_params)
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;
unsigned int id = pps->id;

spin_lock_irq(&pps_idr_lock);
pps = idr_find(&pps_idr, source);
pps_unregister_cdev(pps);

if (!pps) {
BUG();
spin_unlock_irq(&pps_idr_lock);
return;
}
spin_lock_irq(&pps_idr_lock);
idr_remove(&pps_idr, pps->id);
spin_unlock_irq(&pps_idr_lock);

pps_unregister_cdev(pps);
pps_put_source(pps);
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
*
* 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);

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);
pps->info.echo(pps, event, data);

/* Check the event */
pps->current_mode = pps->params.mode;
Expand All @@ -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;
}
Expand All @@ -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;
}
Expand All @@ -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);
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