ptp: Added a brand new class driver for ptp clocks.

This patch adds an infrastructure for hardware clocks that implement
IEEE 1588, the Precision Time Protocol (PTP). A class driver offers a
registration method to particular hardware clock drivers. Each clock is
presented as a standard POSIX clock.

The ancillary clock features are exposed in two different ways, via
the sysfs and by a character device.

Signed-off-by: Richard Cochran <richard.cochran@omicron.at>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: John Stultz <john.stultz@linaro.org>

4 files changed, 231 insertions, 0 deletions

diff --git a/include/linux/Kbuild b/include/linux/Kbuild
index 75cf611641e6..4585836ba664 100644
--- a/include/linux/Kbuild
+++ b/include/linux/Kbuild
@@ -302,6 +302,7 @@ header-y += ppp-comp.h
 header-y += ppp_defs.h
 header-y += pps.h
 header-y += prctl.h
+header-y += ptp_clock.h
 header-y += ptrace.h
 header-y += qnx4_fs.h
 header-y += qnxtypes.h
diff --git a/include/linux/ptp_classify.h b/include/linux/ptp_classify.h
index 943a85ab0020..e07e2742a865 100644
--- a/include/linux/ptp_classify.h
+++ b/include/linux/ptp_classify.h
@@ -25,6 +25,7 @@
 
 #include <linux/if_ether.h>
 #include <linux/if_vlan.h>
+#include <linux/ip.h>
 #include <linux/filter.h>
 #ifdef __KERNEL__
 #include <linux/in.h>
@@ -58,6 +59,12 @@
 #define OFF_NEXT        6
 #define OFF_UDP_DST     2
 
+#define OFF_PTP_SOURCE_UUID     22 /* PTPv1 only */
+#define OFF_PTP_SEQUENCE_ID     30
+#define OFF_PTP_CONTROL         32 /* PTPv1 only */
+
+#define IPV4_HLEN(data) (((struct iphdr *)(data + OFF_IHL))->ihl << 2)
+
 #define IP6_HLEN        40
 #define UDP_HLEN        8
 
diff --git a/include/linux/ptp_clock.h b/include/linux/ptp_clock.h
new file mode 100644
index 000000000000..94e981f810a2
--- /dev/null
+++ b/include/linux/ptp_clock.h
@@ -0,0 +1,84 @@
+/*
+ * PTP 1588 clock support - user space interface
+ *
+ * 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.
+ */
+
+#ifndef _PTP_CLOCK_H_
+#define _PTP_CLOCK_H_
+
+#include <linux/ioctl.h>
+#include <linux/types.h>
+
+/* PTP_xxx bits, for the flags field within the request structures. */
+#define PTP_ENABLE_FEATURE (1<<0)
+#define PTP_RISING_EDGE    (1<<1)
+#define PTP_FALLING_EDGE   (1<<2)
+
+/*
+ * struct ptp_clock_time - represents a time value
+ *
+ * The sign of the seconds field applies to the whole value. The
+ * nanoseconds field is always unsigned. The reserved field is
+ * included for sub-nanosecond resolution, should the demand for
+ * this ever appear.
+ *
+ */
+struct ptp_clock_time {
+        __s64 sec;  /* seconds */
+        __u32 nsec; /* nanoseconds */
+        __u32 reserved;
+};
+
+struct ptp_clock_caps {
+        int max_adj;   /* Maximum frequency adjustment in parts per billon. */
+        int n_alarm;   /* Number of programmable alarms. */
+        int n_ext_ts;  /* Number of external time stamp channels. */
+        int n_per_out; /* Number of programmable periodic signals. */
+        int pps;       /* Whether the clock supports a PPS callback. */
+        int rsv[15];   /* Reserved for future use. */
+};
+
+struct ptp_extts_request {
+        unsigned int index;  /* Which channel to configure. */
+        unsigned int flags;  /* Bit field for PTP_xxx flags. */
+        unsigned int rsv[2]; /* Reserved for future use. */
+};
+
+struct ptp_perout_request {
+        struct ptp_clock_time start;  /* Absolute start time. */
+        struct ptp_clock_time period; /* Desired period, zero means disable. */
+        unsigned int index;           /* Which channel to configure. */
+        unsigned int flags;           /* Reserved for future use. */
+        unsigned int rsv[4];          /* Reserved for future use. */
+};
+
+#define PTP_CLK_MAGIC '='
+
+#define PTP_CLOCK_GETCAPS  _IOR(PTP_CLK_MAGIC, 1, struct ptp_clock_caps)
+#define PTP_EXTTS_REQUEST  _IOW(PTP_CLK_MAGIC, 2, struct ptp_extts_request)
+#define PTP_PEROUT_REQUEST _IOW(PTP_CLK_MAGIC, 3, struct ptp_perout_request)
+#define PTP_ENABLE_PPS     _IOW(PTP_CLK_MAGIC, 4, int)
+
+struct ptp_extts_event {
+        struct ptp_clock_time t; /* Time event occured. */
+        unsigned int index;      /* Which channel produced the event. */
+        unsigned int flags;      /* Reserved for future use. */
+        unsigned int rsv[2];     /* Reserved for future use. */
+};
+
+#endif
diff --git a/include/linux/ptp_clock_kernel.h b/include/linux/ptp_clock_kernel.h
new file mode 100644
index 000000000000..dd2e44fba63e
--- /dev/null
+++ b/include/linux/ptp_clock_kernel.h
@@ -0,0 +1,139 @@
+/*
+ * PTP 1588 clock support
+ *
+ * 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.
+ */
+
+#ifndef _PTP_CLOCK_KERNEL_H_
+#define _PTP_CLOCK_KERNEL_H_
+
+#include <linux/ptp_clock.h>
+
+
+struct ptp_clock_request {
+        enum {
+                PTP_CLK_REQ_EXTTS,
+                PTP_CLK_REQ_PEROUT,
+                PTP_CLK_REQ_PPS,
+        } type;
+        union {
+                struct ptp_extts_request extts;
+                struct ptp_perout_request perout;
+        };
+};
+
+/**
+ * struct ptp_clock_info - decribes a PTP hardware clock
+ *
+ * @owner:     The clock driver should set to THIS_MODULE.
+ * @name:      A short name to identify the clock.
+ * @max_adj:   The maximum possible frequency adjustment, in parts per billon.
+ * @n_alarm:   The number of programmable alarms.
+ * @n_ext_ts:  The number of external time stamp channels.
+ * @n_per_out: The number of programmable periodic signals.
+ * @pps:       Indicates whether the clock supports a PPS callback.
+ *
+ * clock operations
+ *
+ * @adjfreq:  Adjusts the frequency of the hardware clock.
+ *            parameter delta: Desired period change in parts per billion.
+ *
+ * @adjtime:  Shifts the time of the hardware clock.
+ *            parameter delta: Desired change in nanoseconds.
+ *
+ * @gettime:  Reads the current time from the hardware clock.
+ *            parameter ts: Holds the result.
+ *
+ * @settime:  Set the current time on the hardware clock.
+ *            parameter ts: Time value to set.
+ *
+ * @enable:   Request driver to enable or disable an ancillary feature.
+ *            parameter request: Desired resource to enable or disable.
+ *            parameter on: Caller passes one to enable or zero to disable.
+ *
+ * Drivers should embed their ptp_clock_info within a private
+ * structure, obtaining a reference to it using container_of().
+ *
+ * The callbacks must all return zero on success, non-zero otherwise.
+ */
+
+struct ptp_clock_info {
+        struct module *owner;
+        char name[16];
+        s32 max_adj;
+        int n_alarm;
+        int n_ext_ts;
+        int n_per_out;
+        int pps;
+        int (*adjfreq)(struct ptp_clock_info *ptp, s32 delta);
+        int (*adjtime)(struct ptp_clock_info *ptp, s64 delta);
+        int (*gettime)(struct ptp_clock_info *ptp, struct timespec *ts);
+        int (*settime)(struct ptp_clock_info *ptp, const struct timespec *ts);
+        int (*enable)(struct ptp_clock_info *ptp,
+                      struct ptp_clock_request *request, int on);
+};
+
+struct ptp_clock;
+
+/**
+ * ptp_clock_register() - register a PTP hardware clock driver
+ *
+ * @info:  Structure describing the new clock.
+ */
+
+extern struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info);
+
+/**
+ * ptp_clock_unregister() - unregister a PTP hardware clock driver
+ *
+ * @ptp:  The clock to remove from service.
+ */
+
+extern int ptp_clock_unregister(struct ptp_clock *ptp);
+
+
+enum ptp_clock_events {
+        PTP_CLOCK_ALARM,
+        PTP_CLOCK_EXTTS,
+        PTP_CLOCK_PPS,
+};
+
+/**
+ * struct ptp_clock_event - decribes a PTP hardware clock event
+ *
+ * @type:  One of the ptp_clock_events enumeration values.
+ * @index: Identifies the source of the event.
+ * @timestamp: When the event occured.
+ */
+
+struct ptp_clock_event {
+        int type;
+        int index;
+        u64 timestamp;
+};
+
+/**
+ * ptp_clock_event() - notify the PTP layer about an event
+ *
+ * @ptp:    The clock obtained from ptp_clock_register().
+ * @event:  Message structure describing the event.
+ */
+
+extern void ptp_clock_event(struct ptp_clock *ptp,
+                            struct ptp_clock_event *event);
+
+#endif