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Subject[PATCH 2/5] ptp: Added a clock that uses the Linux system time.
This PTP clock simply uses the NTP time adjustment system calls. The
driver can be used in systems that lack a special hardware PTP clock.

Signed-off-by: Richard Cochran <richard.cochran@omicron.at>
---
drivers/ptp/Kconfig | 12 ++++
drivers/ptp/Makefile | 1 +
drivers/ptp/ptp_linux.c | 136 +++++++++++++++++++++++++++++++++++++++++++++++
kernel/time/ntp.c | 2 +
4 files changed, 151 insertions(+), 0 deletions(-)
create mode 100644 drivers/ptp/ptp_linux.c

diff --git a/drivers/ptp/Kconfig b/drivers/ptp/Kconfig
index cd7becb..3aa517a 100644
--- a/drivers/ptp/Kconfig
+++ b/drivers/ptp/Kconfig
@@ -24,4 +24,16 @@ config PTP_1588_CLOCK
To compile this driver as a module, choose M here: the module
will be called ptp_clock.

+config PTP_1588_CLOCK_LINUX
+ tristate "Linux system timer as PTP clock"
+ depends on PTP_1588_CLOCK
+ help
+ This driver adds support for using the standard Linux time
+ source as a PTP clock. This clock is only useful if your PTP
+ programs are using software time stamps for the PTP Ethernet
+ packets.
+
+ To compile this driver as a module, choose M here: the module
+ will be called ptp_linux.
+
endmenu
diff --git a/drivers/ptp/Makefile b/drivers/ptp/Makefile
index b86695c..1651d52 100644
--- a/drivers/ptp/Makefile
+++ b/drivers/ptp/Makefile
@@ -3,3 +3,4 @@
#

obj-$(CONFIG_PTP_1588_CLOCK) += ptp_clock.o
+obj-$(CONFIG_PTP_1588_CLOCK_LINUX) += ptp_linux.o
diff --git a/drivers/ptp/ptp_linux.c b/drivers/ptp/ptp_linux.c
new file mode 100644
index 0000000..f93ae0c
--- /dev/null
+++ b/drivers/ptp/ptp_linux.c
@@ -0,0 +1,136 @@
+/*
+ * PTP 1588 clock using the Linux system clock
+ *
+ * Copyright (C) 2010 OMICRON electronics GmbH
+ *
+ * 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.
+ */
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/hrtimer.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/timex.h>
+
+#include <linux/ptp_clock_kernel.h>
+
+static struct ptp_clock *linux_clock;
+
+DEFINE_SPINLOCK(adjtime_lock);
+
+static int ptp_linux_adjfreq(void *priv, s32 delta)
+{
+ struct timex txc;
+ s64 tmp = delta;
+ int err;
+ txc.freq = div_s64(tmp<<16, 1000);
+ txc.modes = ADJ_FREQUENCY;
+ err = do_adjtimex(&txc);
+ return err < 0 ? err : 0;
+}
+
+static int ptp_linux_adjtime(void *priv, struct timespec *ts)
+{
+ s64 delta;
+ ktime_t now;
+ struct timespec t2;
+ unsigned long flags;
+ int err;
+
+ delta = 1000000000LL * ts->tv_sec + ts->tv_nsec;
+
+ spin_lock_irqsave(&adjtime_lock, flags);
+
+ now = ktime_get_real();
+
+ now = delta < 0 ? ktime_sub_ns(now, -delta) : ktime_add_ns(now, delta);
+
+ t2 = ktime_to_timespec(now);
+
+ err = do_settimeofday(&t2);
+
+ spin_unlock_irqrestore(&adjtime_lock, flags);
+
+ return err;
+}
+
+static int ptp_linux_gettime(void *priv, struct timespec *ts)
+{
+ getnstimeofday(ts);
+ return 0;
+}
+
+static int ptp_linux_settime(void *priv, struct timespec *ts)
+{
+ return do_settimeofday(ts);
+}
+
+static int ptp_linux_gettimer(void *priv, int index, struct itimerspec *ts)
+{
+ /* We do not offer any ancillary features at all. */
+ return -EOPNOTSUPP;
+}
+
+static int ptp_linux_settimer(void *p, int i, int abs, struct itimerspec *ts)
+{
+ /* We do not offer any ancillary features at all. */
+ return -EOPNOTSUPP;
+}
+
+static int ptp_linux_enable(void *priv, struct ptp_clock_request *rq, int on)
+{
+ /* We do not offer any ancillary features at all. */
+ return -EOPNOTSUPP;
+}
+
+static struct ptp_clock_info ptp_linux_caps = {
+ .owner = THIS_MODULE,
+ .name = "Linux timer",
+ .max_adj = 512000,
+ .n_alarm = 0,
+ .n_ext_ts = 0,
+ .n_per_out = 0,
+ .pps = 0,
+ .priv = NULL,
+ .adjfreq = ptp_linux_adjfreq,
+ .adjtime = ptp_linux_adjtime,
+ .gettime = ptp_linux_gettime,
+ .settime = ptp_linux_settime,
+ .gettimer = ptp_linux_gettimer,
+ .settimer = ptp_linux_settimer,
+ .enable = ptp_linux_enable,
+};
+
+/* module operations */
+
+static void __exit ptp_linux_exit(void)
+{
+ ptp_clock_unregister(linux_clock);
+}
+
+static int __init ptp_linux_init(void)
+{
+ linux_clock = ptp_clock_register(&ptp_linux_caps);
+
+ return IS_ERR(linux_clock) ? PTR_ERR(linux_clock) : 0;
+}
+
+module_init(ptp_linux_init);
+module_exit(ptp_linux_exit);
+
+MODULE_AUTHOR("Richard Cochran <richard.cochran@omicron.at>");
+MODULE_DESCRIPTION("PTP clock using the Linux system timer");
+MODULE_LICENSE("GPL");
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index c631168..eba3bcf 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -14,6 +14,7 @@
#include <linux/timex.h>
#include <linux/time.h>
#include <linux/mm.h>
+#include <linux/module.h>

/*
* NTP timekeeping variables:
@@ -535,6 +536,7 @@ int do_adjtimex(struct timex *txc)

return result;
}
+EXPORT_SYMBOL(do_adjtimex);

static int __init ntp_tick_adj_setup(char *str)
{
--
1.7.0.4


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