[PATCHv6 14/16] pps: add kernel consumer support

Alexander Gordeev
2010-12-17T19:56:20Z

Add an optional feature of PPSAPI, kernel consumer support, which uses
the added hardpps() function.

Acked-by: Rodolfo Giometti <giometti@linux.it>
Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su>
---
Documentation/ioctl/ioctl-number.txt | 2 +-
drivers/pps/Kconfig | 1 +
drivers/pps/kapi.c | 27 +++++++++++++++
drivers/pps/pps.c | 62 +++++++++++++++++++++++++++++++++-
include/linux/pps.h | 7 ++++
include/linux/pps_kernel.h | 6 +++
6 files changed, 103 insertions(+), 2 deletions(-)

diff --git a/Documentation/ioctl/ioctl-number.txt b/Documentation/ioctl/ioctl-number.txt
index 63ffd78..7081847 100644
--- a/Documentation/ioctl/ioctl-number.txt
+++ b/Documentation/ioctl/ioctl-number.txt
@@ -249,7 +249,7 @@ Code Seq#(hex) Include File Comments
'p' 40-7F linux/nvram.h
'p' 80-9F linux/ppdev.h user-space parport
<mailto:tim@cyberelk.net>
-'p' A1-A4 linux/pps.h LinuxPPS
+'p' A1-A5 linux/pps.h LinuxPPS
<mailto:giometti@linux.it>
'q' 00-1F linux/serio.h
'q' 80-FF linux/telephony.h Internet PhoneJACK, Internet LineJACK
diff --git a/drivers/pps/Kconfig b/drivers/pps/Kconfig
index 33c9126..4823e47 100644
--- a/drivers/pps/Kconfig
+++ b/drivers/pps/Kconfig
@@ -7,6 +7,7 @@ menu "PPS support"
config PPS
tristate "PPS support"
depends on EXPERIMENTAL
+ select NTP_PPS
---help---
PPS (Pulse Per Second) is a special pulse provided by some GPS
antennae. Userland can use it to get a high-precision time
diff --git a/drivers/pps/kapi.c b/drivers/pps/kapi.c
index ebf3374..ed78f6d 100644
--- a/drivers/pps/kapi.c
+++ b/drivers/pps/kapi.c
@@ -26,12 +26,23 @@
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/time.h>
+#include <linux/timex.h>
#include <linux/spinlock.h>
#include <linux/fs.h>
#include <linux/pps_kernel.h>
#include <linux/slab.h>

/*
+ * Global variables
+ */
+
+/* state variables to bind kernel consumer */
+/* PPS API (RFC 2783): current source and mode for ``kernel consumer'' */
+DEFINE_SPINLOCK(pps_kc_hardpps_lock);
+void *pps_kc_hardpps_dev; /* some unique pointer to device */
+int pps_kc_hardpps_mode; /* mode bits for kernel consumer */
+
+/*
* Local functions
*/

@@ -139,6 +150,16 @@ EXPORT_SYMBOL(pps_register_source);

void pps_unregister_source(struct pps_device *pps)
{
+ spin_lock_irq(&pps_kc_hardpps_lock);
+ if (pps == pps_kc_hardpps_dev) {
+ pps_kc_hardpps_mode = 0;
+ pps_kc_hardpps_dev = NULL;
+ spin_unlock_irq(&pps_kc_hardpps_lock);
+ dev_info(pps->dev, "unbound kernel consumer"
+ " on device removal\n");
+ } else
+ spin_unlock_irq(&pps_kc_hardpps_lock);
+
pps_unregister_cdev(pps);

/* don't have to kfree(pps) here because it will be done on
@@ -211,6 +232,12 @@ void pps_event(struct pps_device *pps, struct pps_event_time *ts, int event,
captured = ~0;
}

+ /* Pass some events to kernel consumer if activated */
+ spin_lock(&pps_kc_hardpps_lock);
+ if (pps == pps_kc_hardpps_dev && event & pps_kc_hardpps_mode)
+ hardpps(&ts->ts_real, &ts->ts_raw);
+ spin_unlock(&pps_kc_hardpps_lock);
+
/* Wake up if captured something */
if (captured) {
pps->last_ev++;
diff --git a/drivers/pps/pps.c b/drivers/pps/pps.c
index 54964a5..76f4b5e 100644
--- a/drivers/pps/pps.c
+++ b/drivers/pps/pps.c
@@ -197,9 +197,69 @@ static long pps_cdev_ioctl(struct file *file,

break;
}
+ case PPS_KC_BIND: {
+ struct pps_bind_args bind_args;
+
+ dev_dbg(pps->dev, "PPS_KC_BIND\n");
+
+ /* Check the capabilities */
+ if (!capable(CAP_SYS_TIME))
+ return -EPERM;
+
+ if (copy_from_user(&bind_args, uarg,
+ sizeof(struct pps_bind_args)))
+ return -EFAULT;
+
+ /* Check for supported capabilities */
+ if ((bind_args.edge & ~pps->info.mode) != 0) {
+ dev_err(pps->dev, "unsupported capabilities (%x)\n",
+ bind_args.edge);
+ return -EINVAL;
+ }
+
+ /* Validate parameters roughly */
+ if (bind_args.tsformat != PPS_TSFMT_TSPEC ||
+ (bind_args.edge & ~PPS_CAPTUREBOTH) != 0 ||
+ bind_args.consumer != PPS_KC_HARDPPS) {
+ dev_err(pps->dev, "invalid kernel consumer bind"
+ " parameters (%x)\n", bind_args.edge);
+ return -EINVAL;
+ }
+
+ /* Check if another consumer is already bound */
+ spin_lock_irq(&pps_kc_hardpps_lock);
+
+ if (bind_args.edge == 0)
+ if (pps_kc_hardpps_dev == pps) {
+ pps_kc_hardpps_mode = 0;
+ pps_kc_hardpps_dev = NULL;
+ spin_unlock_irq(&pps_kc_hardpps_lock);
+ dev_info(pps->dev, "unbound kernel"
+ " consumer\n");
+ } else {
+ spin_unlock_irq(&pps_kc_hardpps_lock);
+ dev_err(pps->dev, "selected kernel consumer"
+ " is not bound\n");
+ return -EINVAL;
+ }
+ else
+ if (pps_kc_hardpps_dev == NULL ||
+ pps_kc_hardpps_dev == pps) {
+ pps_kc_hardpps_mode = bind_args.edge;
+ pps_kc_hardpps_dev = pps;
+ spin_unlock_irq(&pps_kc_hardpps_lock);
+ dev_info(pps->dev, "bound kernel consumer: "
+ "edge=0x%x\n", bind_args.edge);
+ } else {
+ spin_unlock_irq(&pps_kc_hardpps_lock);
+ dev_err(pps->dev, "another kernel consumer"
+ " is already bound\n");
+ return -EINVAL;
+ }
+ break;
+ }
default:
return -ENOTTY;
- break;
}

return 0;
diff --git a/include/linux/pps.h b/include/linux/pps.h
index 0194ab0..a9bb1d9 100644
--- a/include/linux/pps.h
+++ b/include/linux/pps.h
@@ -114,11 +114,18 @@ struct pps_fdata {
struct pps_ktime timeout;
};

+struct pps_bind_args {
+ int tsformat; /* format of time stamps */
+ int edge; /* selected event type */
+ int consumer; /* selected kernel consumer */
+};
+
#include <linux/ioctl.h>

#define PPS_GETPARAMS _IOR('p', 0xa1, struct pps_kparams *)
#define PPS_SETPARAMS _IOW('p', 0xa2, struct pps_kparams *)
#define PPS_GETCAP _IOR('p', 0xa3, int *)
#define PPS_FETCH _IOWR('p', 0xa4, struct pps_fdata *)
+#define PPS_KC_BIND _IOW('p', 0xa5, struct pps_bind_args *)

#endif /* _PPS_H_ */
diff --git a/include/linux/pps_kernel.h b/include/linux/pps_kernel.h
index 6ae8898..2302274 100644
--- a/include/linux/pps_kernel.h
+++ b/include/linux/pps_kernel.h
@@ -79,6 +79,12 @@ struct pps_device {

extern struct device_attribute pps_attrs[];

+/* state variables to bind kernel consumer */
+/* PPS API (RFC 2783): current source and mode for ``kernel consumer'' */
+extern spinlock_t pps_kc_hardpps_lock;
+extern void *pps_kc_hardpps_dev; /* some unique pointer to device */
+extern int pps_kc_hardpps_mode; /* mode bits for kernel consumer */
+
/*
* Exported functions
*/
--
1.7.2.3