[LinuxPPS] [PATCH 02a/12] PPS: get rid of some pps_get_source() calls
George Spelvin
linux at horizon.com
Tue Feb 10 04:57:30 CET 2009
This changes the kernel API to pass around a struct pps_device * instead
of an integer ID where possible. In particular, avoiding the need to
call pps_get_source() in the pps_event() interrupt handler is a win.
(The comment above pps_event() is actually foreshadowing the next
commit in the series; it's not technically correct yet.)
---
Documentation/pps/pps.txt | 8 ++++--
drivers/pps/clients/ktimer.c | 19 +++++++-------
drivers/pps/clients/pps-ldisc.c | 26 ++++++++++---------
drivers/pps/kapi.c | 51 ++++++++++++++++++--------------------
include/linux/pps.h | 13 ++++++----
5 files changed, 61 insertions(+), 56 deletions(-)
diff --git a/Documentation/pps/pps.txt b/Documentation/pps/pps.txt
index 125f4ab..8470a69 100644
--- a/Documentation/pps/pps.txt
+++ b/Documentation/pps/pps.txt
@@ -85,12 +85,12 @@ pps_source_info_s as follows:
and then calling the function pps_register_source() in your
intialization routine as follows:
- source = pps_register_source(&pps_ktimer_info,
+ pps = pps_register_source(&pps_ktimer_info,
PPS_CAPTUREASSERT | PPS_OFFSETASSERT);
The pps_register_source() prototype is:
- int pps_register_source(struct pps_source_info_s *info, int default_params)
+ struct pps_source *pps_register_source(struct pps_source_info_s *info, int default_params)
where "info" is a pointer to a structure that describes a particular
PPS source, "default_params" tells the system what the initial default
@@ -98,11 +98,13 @@ parameters for the device should be (it is obvious that these parameters
must be a subset of ones defined in the struct
pps_source_info_s which describe the capabilities of the driver).
+The return value is either a pointer to a pps struct or an ERR_PTR.
+
Once you have registered a new PPS source into the system you can
signal an assert event (for example in the interrupt handler routine)
just using:
- pps_event(source, &ts, PPS_CAPTUREASSERT, ptr)
+ pps_event(pps, &ts, PPS_CAPTUREASSERT, ptr)
where "ts" is the event's timestamp.
diff --git a/drivers/pps/clients/ktimer.c b/drivers/pps/clients/ktimer.c
index 259baa7..dc837a0 100644
--- a/drivers/pps/clients/ktimer.c
+++ b/drivers/pps/clients/ktimer.c
@@ -25,6 +25,7 @@
#include <linux/init.h>
#include <linux/time.h>
#include <linux/timer.h>
+#include <linux/err.h>
#include <linux/pps.h>
@@ -32,7 +33,7 @@
* Global variables
*/
-static int source;
+static struct pps_device *source;
static struct timer_list ktimer;
/*
@@ -62,12 +63,12 @@ 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",
event & PPS_CAPTUREASSERT ? "assert" : "",
event & PPS_CAPTURECLEAR ? "clear" : "",
- source);
+ pps->id);
}
/*
@@ -98,20 +99,20 @@ static void __exit pps_ktimer_exit(void)
static int __init pps_ktimer_init(void)
{
- int ret;
+ struct pps_device *pps;
- ret = pps_register_source(&pps_ktimer_info,
+ pps = pps_register_source(&pps_ktimer_info,
PPS_CAPTUREASSERT | PPS_OFFSETASSERT);
- if (ret < 0) {
+ if (IS_ERR(pps)) {
printk(KERN_ERR "cannot register ktimer source\n");
- return ret;
+ return PTR_ERR(pps);
}
- source = ret;
+ source = pps;
setup_timer(&ktimer, pps_ktimer_event, 0);
mod_timer(&ktimer, jiffies + HZ);
- pr_info("ktimer PPS source registered at %d\n", source);
+ pr_info("ktimer PPS source registered at %d\n", pps->id);
return 0;
}
diff --git a/drivers/pps/clients/pps-ldisc.c b/drivers/pps/clients/pps-ldisc.c
index 0406f40..bc8b56a 100644
--- a/drivers/pps/clients/pps-ldisc.c
+++ b/drivers/pps/clients/pps-ldisc.c
@@ -29,7 +29,7 @@
static void pps_tty_dcd_change(struct tty_struct *tty, unsigned int status,
struct timespec *ts)
{
- long id = (long) tty->disc_data;
+ struct pps_device *pps = tty->disc_data;
struct timespec __ts;
struct pps_ktime pps_ts;
@@ -42,11 +42,11 @@ static void pps_tty_dcd_change(struct tty_struct *tty, unsigned int status,
pps_ts.nsec = ts->tv_nsec;
/* Now do the PPS event report */
- pps_event(id, &pps_ts, status ? PPS_CAPTUREASSERT : PPS_CAPTURECLEAR,
+ pps_event(pps, &pps_ts, status ? PPS_CAPTUREASSERT : PPS_CAPTURECLEAR,
NULL);
pr_debug("PPS %s at %lu on source #%d\n",
- status ? "assert" : "clear", jiffies, (int) id);
+ status ? "assert" : "clear", jiffies, pps->id);
}
static int pps_tty_open(struct tty_struct *tty)
@@ -54,7 +54,8 @@ 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;
- long ret;
+ struct pps_device *pps;
+ int ret;
info.owner = THIS_MODULE;
info.dev = NULL;
@@ -64,30 +65,31 @@ 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 (IS_ERR(pps)) {
pr_err("cannot register PPS source \"%s\"\n", info.path);
- return ret;
+ return PTR_ERR(pps);
}
- tty->disc_data = (void *) ret;
+ tty->disc_data = pps;
/* Should open N_TTY ldisc too */
ret = n_tty_open(tty);
if (ret < 0)
- pps_unregister_source((long) tty->disc_data);
+ pps_unregister_source(tty->disc_data);
- pr_info("PPS source #%d \"%s\" added\n", (int) ret, info.path);
+ pr_info("PPS source #%d \"%s\" added\n", pps->id, info.path);
return 0;
}
static void pps_tty_close(struct tty_struct *tty)
{
- long id = (long) tty->disc_data;
+ struct pps_device *pps = tty->disc_data;
+ int id = pps->id;
- pps_unregister_source(id);
n_tty_close(tty);
+ pps_unregister_source(pps);
pr_info("PPS source #%d removed\n", (int) id);
}
diff --git a/drivers/pps/kapi.c b/drivers/pps/kapi.c
index 917b379..4d6a2ed 100644
--- a/drivers/pps/kapi.c
+++ b/drivers/pps/kapi.c
@@ -124,7 +124,8 @@ exit:
* 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_register_source(struct pps_source_info *info, int default_params)
{
struct pps_device *pps;
int id;
@@ -198,7 +199,7 @@ 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);
@@ -211,7 +212,7 @@ kfree_pps:
pps_register_source_exit:
printk(KERN_ERR "pps: %s: unable to register source\n", info->name);
- return err;
+ return ERR_PTR(err);
}
EXPORT_SYMBOL(pps_register_source);
@@ -222,27 +223,19 @@ EXPORT_SYMBOL(pps_register_source);
* 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);
-
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
+ * @pps: the pps_device structure
* @ts: the event timestamp
* @event: the event type
* @data: userdef pointer
@@ -252,23 +245,30 @@ EXPORT_SYMBOL(pps_unregister_source);
*
* If an echo function is associated with the PPS source it will be called
* as:
- * pps->info.echo(source, event, data);
+ * pps->info.echo(pps->id, event, data);
+ *
+ * NOTE: This function does no locking. The caller must ensure that
+ * a) calls are serialized, and
+ * b) do not occur after pps_unregister_source is called.
+ * For current PPS clients, this is taken care of by:
+ * serial: a) struct uart_port's lock field, b) ldisc refcount
+ * ktimer: a) struct tvec_base's lock, b) del_timer_sync()
*/
-void pps_event(int source, struct pps_ktime *ts, int event, void *data)
+void
+pps_event(struct pps_device *pps, struct pps_ktime *ts, int event, void *data)
{
- struct pps_device *pps;
unsigned long flags;
+ if (!pps)
+ return;
+
if ((event & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR)) == 0) {
printk(KERN_ERR "pps: unknown event (%x) for source %d\n",
- event, source);
+ event, pps->id);
return;
}
-
- pps = pps_get_source(source);
- if (!pps)
- return;
+ event &= PPS_CAPTUREASSERT | PPS_CAPTURECLEAR;
pr_debug("PPS event on source %d at %llu.%06u\n",
pps->id, (unsigned long long) ts->sec, ts->nsec);
@@ -277,7 +277,7 @@ void pps_event(int source, struct pps_ktime *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;
@@ -290,7 +290,7 @@ void pps_event(int source, struct pps_ktime *ts, int event, void *data)
pps->assert_tu = *ts;
pps->assert_sequence++;
pr_debug("capture assert seq #%u for source %d\n",
- pps->assert_sequence, source);
+ pps->assert_sequence, pps->id);
}
if (event & PPS_CAPTURECLEAR) {
/* We have to add an offset? */
@@ -301,7 +301,7 @@ void pps_event(int source, struct pps_ktime *ts, int event, void *data)
pps->clear_tu = *ts;
pps->clear_sequence++;
pr_debug("capture clear seq #%u for source %d\n",
- pps->clear_sequence, source);
+ pps->clear_sequence, pps->id);
}
pps->go = ~0;
@@ -310,8 +310,5 @@ void pps_event(int source, struct pps_ktime *ts, int event, void *data)
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);
diff --git a/include/linux/pps.h b/include/linux/pps.h
index d7719b3..c8cacdc 100644
--- a/include/linux/pps.h
+++ b/include/linux/pps.h
@@ -131,14 +131,16 @@ struct pps_fdata {
* Global defines
*/
+struct pps_device;
+
/* The specific PPS source info */
struct pps_source_info {
char name[PPS_MAX_NAME_LEN]; /* simbolic name */
char path[PPS_MAX_NAME_LEN]; /* path of connected device */
int mode; /* PPS's allowed mode */
- void (*echo)(int source, int event, void *data); /* PPS echo function */
-
+ void (*echo)(struct pps_device *pps, int event, void *data);
+ /* PPS echo function */
struct module *owner;
struct device *dev;
};
@@ -184,12 +186,13 @@ extern struct device_attribute pps_attrs[];
struct pps_device *pps_get_source(int source);
extern void pps_put_source(struct pps_device *pps);
-extern int pps_register_source(struct pps_source_info *info,
+extern struct pps_device *pps_register_source(struct pps_source_info *info,
int default_params);
-extern void pps_unregister_source(int source);
+extern void pps_unregister_source(struct pps_device *pps);
extern int pps_register_cdev(struct pps_device *pps);
extern void pps_unregister_cdev(struct pps_device *pps);
-extern void pps_event(int source, struct pps_ktime *ts, int event, void *data);
+extern void pps_event(struct pps_device *pps, struct pps_ktime *ts,
+ int event, void *data);
#endif /* __KERNEL__ */
--
1.6.0.6
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