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Date:	Wed, 24 Nov 2010 19:15:53 +0300
From:	Alexander Gordeev <lasaine@....cs.msu.su>
To:	linux-kernel@...r.kernel.org
Cc:	"Nikita V\. Youshchenko" <yoush@...msu.su>,
	linuxpps@...enneenne.com, Rodolfo Giometti <giometti@...eenne.com>,
	Alexander Gordeev <lasaine@....cs.msu.su>,
	Randy Dunlap <rdunlap@...otime.net>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Thomas Weber <weber@...science.de>,
	Mike Frysinger <vapier.adi@...il.com>,
	Stefan Richter <stefanr@...6.in-berlin.de>,
	Jiri Kosina <jkosina@...e.cz>,
	John Stultz <johnstul@...ibm.com>, Tejun Heo <tj@...nel.org>,
	linux-doc@...r.kernel.org
Subject: [PATCHv5 15/17] pps: add kernel consumer support

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

Signed-off-by: Alexander Gordeev <lasaine@....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 33223ff..de2b113 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@...erelk.net>
-'p'	A1-A4	linux/pps.h		LinuxPPS
+'p'	A1-A5	linux/pps.h		LinuxPPS
 					<mailto:giometti@...ux.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

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