[PATCHv7 14/16] pps: add kernel consumer support

Alexander Gordeev
2010-12-20T11:56:12Z

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

Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su>
---
Documentation/ioctl/ioctl-number.txt | 2 +-
drivers/pps/Makefile | 1 +
drivers/pps/kapi.c | 6 ++
drivers/pps/kc.c | 123 ++++++++++++++++++++++++++++++++++
drivers/pps/kc.h | 47 +++++++++++++
drivers/pps/pps.c | 38 ++++++++++-
include/linux/pps.h | 7 ++
7 files changed, 222 insertions(+), 2 deletions(-)
create mode 100644 drivers/pps/kc.c
create mode 100644 drivers/pps/kc.h

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/Makefile b/drivers/pps/Makefile
index 98960dd..77c23457 100644
--- a/drivers/pps/Makefile
+++ b/drivers/pps/Makefile
@@ -3,6 +3,7 @@
#

pps_core-y := pps.o kapi.o sysfs.o
+pps_core-$(CONFIG_NTP_PPS) += kc.o
obj-$(CONFIG_PPS) := pps_core.o
obj-y += clients/

diff --git a/drivers/pps/kapi.c b/drivers/pps/kapi.c
index ebf3374..cba1b43 100644
--- a/drivers/pps/kapi.c
+++ b/drivers/pps/kapi.c
@@ -26,11 +26,14 @@
#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>

+#include "kc.h"
+
/*
* Local functions
*/
@@ -139,6 +142,7 @@ EXPORT_SYMBOL(pps_register_source);

void pps_unregister_source(struct pps_device *pps)
{
+ pps_kc_remove(pps);
pps_unregister_cdev(pps);

/* don't have to kfree(pps) here because it will be done on
@@ -211,6 +215,8 @@ void pps_event(struct pps_device *pps, struct pps_event_time *ts, int event,
captured = ~0;
}

+ pps_kc_event(pps, ts, event);
+
/* Wake up if captured something */
if (captured) {
pps->last_ev++;
diff --git a/drivers/pps/kc.c b/drivers/pps/kc.c
new file mode 100644
index 0000000..059a6c0
--- /dev/null
+++ b/drivers/pps/kc.c
@@ -0,0 +1,123 @@
+/*
+ * PPS kernel consumer API
+ *
+ * Copyright (C) 2009-2010 Alexander Gordeev <lasaine@lvk.cs.msu.su>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/pps_kernel.h>
+
+#include "kc.h"
+
+/*
+ * Global variables
+ */
+
+/* state variables to bind kernel consumer */
+DEFINE_SPINLOCK(pps_kc_hardpps_lock);
+/* PPS API (RFC 2783): current source and mode for kernel consumer */
+struct pps_device *pps_kc_hardpps_dev; /* unique pointer to device */
+int pps_kc_hardpps_mode; /* mode bits for kernel consumer */
+
+/* pps_kc_bind - control PPS kernel consumer binding
+ * @pps: the PPS source
+ * @bind_args: kernel consumer bind parameters
+ *
+ * This function is used to bind or unbind PPS kernel consumer according to
+ * supplied parameters. Should not be called in interrupt context.
+ */
+int pps_kc_bind(struct pps_device *pps, struct pps_bind_args *bind_args)
+{
+ /* 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;
+ }
+
+ return 0;
+}
+
+/* pps_kc_remove - unbind kernel consumer on PPS source removal
+ * @pps: the PPS source
+ *
+ * This function is used to disable kernel consumer on PPS source removal
+ * if this source was bound to PPS kernel consumer. Can be called on any
+ * source safely. Should not be called in interrupt context.
+ */
+void pps_kc_remove(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_kc_event - call hardpps() on PPS event
+ * @pps: the PPS source
+ * @ts: PPS event timestamp
+ * @event: PPS event edge
+ *
+ * This function calls hardpps() when an event from bound PPS source occurs.
+ */
+void pps_kc_event(struct pps_device *pps, struct pps_event_time *ts,
+ int event)
+{
+ unsigned long flags;
+
+ /* Pass some events to kernel consumer if activated */
+ spin_lock_irqsave(&pps_kc_hardpps_lock, flags);
+ if (pps == pps_kc_hardpps_dev && event & pps_kc_hardpps_mode)
+ hardpps(&ts->ts_real, &ts->ts_raw);
+ spin_unlock_irqrestore(&pps_kc_hardpps_lock, flags);
+}
+
diff --git a/drivers/pps/kc.h b/drivers/pps/kc.h
new file mode 100644
index 0000000..1cdcf75
--- /dev/null
+++ b/drivers/pps/kc.h
@@ -0,0 +1,47 @@
+/*
+ * PPS kernel consumer API header
+ *
+ * Copyright (C) 2009-2010 Alexander Gordeev <lasaine@lvk.cs.msu.su>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#ifndef LINUX_PPS_KC_H
+#define LINUX_PPS_KC_H
+
+#include <linux/errno.h>
+#include <linux/pps_kernel.h>
+
+#ifdef CONFIG_NTP_PPS
+
+extern int pps_kc_bind(struct pps_device *pps,
+ struct pps_bind_args *bind_args);
+extern void pps_kc_remove(struct pps_device *pps);
+extern void pps_kc_event(struct pps_device *pps,
+ struct pps_event_time *ts, int event);
+
+
+#else /* CONFIG_NTP_PPS */
+
+static inline int pps_kc_bind(struct pps_device *pps,
+ struct pps_bind_args *bind_args) { return -EOPNOTSUPP; }
+static inline void pps_kc_remove(struct pps_device *pps) {}
+static inline void pps_kc_event(struct pps_device *pps,
+ struct pps_event_time *ts, int event) {}
+
+#endif /* CONFIG_NTP_PPS */
+
+#endif /* LINUX_PPS_KC_H */
+
diff --git a/drivers/pps/pps.c b/drivers/pps/pps.c
index 9e15cf1..2baadd2 100644
--- a/drivers/pps/pps.c
+++ b/drivers/pps/pps.c
@@ -33,6 +33,8 @@
#include <linux/pps_kernel.h>
#include <linux/slab.h>

+#include "kc.h"
+
/*
* Local variables
*/
@@ -198,9 +200,43 @@ 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;
+ }
+
+ err = pps_kc_bind(pps, &bind_args);
+ if (err < 0)
+ return err;
+
+ 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_ */
--
1.7.2.3