Merge branch 'timekeeping' of bitbucket.org:nuttx/nuttx

arch/arm/Kconfig

@@ -225,6 +225,7 @@ config ARCH_CHIP_STM32
 	select ARCH_HAVE_I2CRESET
 	select ARCH_HAVE_HEAPCHECK
 	select ARCH_HAVE_TICKLESS
+	select ARCH_HAVE_TIMEKEEPING
 	select ARMV7M_HAVE_STACKCHECK
 	---help---
 		STMicro STM32 architectures (ARM Cortex-M3/4).

arch/arm/src/stm32/stm32_freerun.c

@@ -53,7 +53,7 @@
 #ifdef CONFIG_STM32_FREERUN
 
 /****************************************************************************
- * Private Functions
+ * Private Data
  ****************************************************************************/
 
 static struct stm32_freerun_s *g_freerun;
@@ -80,6 +80,7 @@ static struct stm32_freerun_s *g_freerun;
  *
  ****************************************************************************/
 
+#ifndef CONFIG_CLOCK_TIMEKEEPING
 static int stm32_freerun_handler(int irq, void *context)
 {
   struct stm32_freerun_s *freerun = g_freerun;
@@ -90,6 +91,7 @@ static int stm32_freerun_handler(int irq, void *context)
   STM32_TIM_ACKINT(freerun->tch, 0);
   return OK;
 }
+#endif /* CONFIG_CLOCK_TIMEKEEPING */
 
 /****************************************************************************
  * Public Functions
@@ -140,15 +142,21 @@ int stm32_freerun_initialize(struct stm32_freerun_s *freerun, int chan,
    * success.
    */
 
-  freerun->chan     = chan;
+  freerun->chan         = chan;
-  freerun->running  = false;
+  freerun->running      = false;
-  freerun->overflow = 0;
 
-  g_freerun = freerun;
+#ifdef CONFIG_CLOCK_TIMEKEEPING
+  freerun->counter_mask = 0xffffffffull;
+#endif
+
+#ifndef CONFIG_CLOCK_TIMEKEEPING
+  freerun->overflow     = 0;
+  g_freerun             = freerun;
 
   /* Set up to receive the callback when the counter overflow occurs */
 
   STM32_TIM_SETISR(freerun->tch, stm32_freerun_handler, 0);
+#endif
 
   /* Set timer period */
 
@@ -157,8 +165,11 @@ int stm32_freerun_initialize(struct stm32_freerun_s *freerun, int chan,
   /* Start the counter */
 
   STM32_TIM_SETMODE(freerun->tch, STM32_TIM_MODE_UP);
+
+#ifndef CONFIG_CLOCK_TIMEKEEPING
   STM32_TIM_ACKINT(freerun->tch, 0);
   STM32_TIM_ENABLEINT(freerun->tch, 0);
+#endif
 
   return OK;
 }
@@ -182,6 +193,8 @@ int stm32_freerun_initialize(struct stm32_freerun_s *freerun, int chan,
  *
  ****************************************************************************/
 
+#ifndef CONFIG_CLOCK_TIMEKEEPING
+
 int stm32_freerun_counter(struct stm32_freerun_s *freerun,
                           struct timespec *ts)
 {
@@ -257,6 +270,16 @@ int stm32_freerun_counter(struct stm32_freerun_s *freerun,
   return OK;
 }
 
+#else /* CONFIG_CLOCK_TIMEKEEPING */
+
+int stm32_freerun_counter(struct stm32_freerun_s *freerun, uint64_t *counter)
+{
+  *counter = (uint64_t)STM32_TIM_GETCOUNTER(freerun->tch);
+  return OK;
+}
+
+#endif /* CONFIG_CLOCK_TIMEKEEPING */
+
 /****************************************************************************
  * Name: stm32_freerun_uninitialize
  *

arch/arm/src/stm32/stm32_freerun.h

@@ -64,9 +64,16 @@ struct stm32_freerun_s
 {
   uint8_t chan;                    /* The timer/counter in use */
   bool running;                    /* True: the timer is running */
-  uint32_t overflow;               /* Timer counter overflow */
   FAR struct stm32_tim_dev_s *tch; /* Handle returned by stm32_tim_init() */
   uint32_t frequency;
+
+#ifndef CONFIG_CLOCK_TIMEKEEPING
+  uint32_t overflow;               /* Timer counter overflow */
+#endif
+
+#ifdef CONFIG_CLOCK_TIMEKEEPING
+  uint64_t counter_mask;
+#endif
 };
 
 /****************************************************************************
@@ -127,9 +134,18 @@ int stm32_freerun_initialize(struct stm32_freerun_s *freerun, int chan,
  *
  ****************************************************************************/
 
+#ifndef CONFIG_CLOCK_TIMEKEEPING
+
 int stm32_freerun_counter(struct stm32_freerun_s *freerun,
                           struct timespec *ts);
 
+#else /* CONFIG_CLOCK_TIMEKEEPING */
+
+int stm32_freerun_counter(struct stm32_freerun_s *freerun,
+                          uint64_t *counter);
+
+#endif /* CONFIG_CLOCK_TIMEKEEPING */
+
 /****************************************************************************
  * Name: stm32_freerun_uninitialize
  *

arch/arm/src/stm32/stm32_tickless.c

@@ -272,11 +272,44 @@ void up_timer_initialize(void)
  *
  ****************************************************************************/
 
+#ifndef CONFIG_CLOCK_TIMEKEEPING
+
 int up_timer_gettime(FAR struct timespec *ts)
 {
   return stm32_freerun_counter(&g_tickless.freerun, ts);
 }
 
+#else
+
+int up_timer_getcounter(FAR uint64_t *cycles)
+{
+  return stm32_freerun_counter(&g_tickless.freerun, cycles);
+}
+
+#endif /* CONFIG_CLOCK_TIMEKEEPING */
+
+/****************************************************************************
+ * Name: up_timer_getmask
+ *
+ * Description:
+ *   To be provided
+ *
+ * Input Parameters:
+ *   mask - Location to return the 64-bit mask
+ *
+ * Returned Value:
+ *   None
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_CLOCK_TIMEKEEPING
+void up_timer_getmask(FAR uint64_t *mask)
+{
+  DEBUGASSERT(mask != NULL);
+  *mask = g_tickless.freerun.counter_mask;
+}
+#endif /* CONFIG_CLOCK_TIMEKEEPING */
+
 /****************************************************************************
  * Name: up_timer_cancel
  *

include/nuttx/arch.h

@@ -1496,10 +1496,15 @@ void up_timer_initialize(void);
  *
  ****************************************************************************/
 
-#ifdef CONFIG_SCHED_TICKLESS
+#if defined(CONFIG_SCHED_TICKLESS) && !defined(CONFIG_CLOCK_TIMEKEEPING)
 int up_timer_gettime(FAR struct timespec *ts);
 #endif
 
+#ifdef CONFIG_CLOCK_TIMEKEEPING
+int up_timer_getcounter(FAR uint64_t *cycles);
+void up_timer_getmask(FAR uint64_t *mask);
+#endif
+
 /****************************************************************************
  * Name: up_alarm_cancel
  *

include/sys/syscall.h

@@ -215,7 +215,12 @@
 #define SYS_clock_getres               (__SYS_clock+1)
 #define SYS_clock_gettime              (__SYS_clock+2)
 #define SYS_clock_settime              (__SYS_clock+3)
-#define __SYS_timers                   (__SYS_clock+4)
+#ifdef CONFIG_CLOCK_TIMEKEEPING
+#  define SYS_adjtime                  (__SYS_clock+4)
+#  define __SYS_timers                 (__SYS_clock+5)
+#else
+#  define __SYS_timers                 (__SYS_clock+4)
+#endif
 
 /* The following are defined only if POSIX timers are supported */
 

include/sys/time.h

@@ -1,7 +1,7 @@
 /****************************************************************************
  * include/sys/time.h
  *
- *   Copyright (C) 2009, 2015 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2009, 2015-2016 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -112,6 +112,7 @@
 /****************************************************************************
  * Public Type Definitions
  ****************************************************************************/
+
 /* struct timeval represents time as seconds plus microseconds */
 
 struct timeval
@@ -190,6 +191,46 @@ int gettimeofday(FAR struct timeval *tv, FAR struct timezone *tz);
 
 int settimeofday(FAR const struct timeval *tv, FAR struct timezone *tz);
 
+/****************************************************************************
+ * Name: adjtime
+ *
+ * Description:
+ *   The adjtime() function gradually adjusts the system clock (as returned
+ *   by gettimeofday(2)).  The amount of time by which the clock is to be
+ *   adjusted is specified in the structure pointed to by delta.
+ *
+ *   This structure has the following form:
+ *
+ *     struct timeval
+ *       {
+ *         time_t      tv_sec;     (seconds)
+ *         suseconds_t tv_usec;    (microseconds)
+ *       };
+ *
+ *   If the adjustment in delta is positive, then the system clock is
+ *   speeded up by some small percentage (i.e., by adding a small amount of
+ *   time to the clock value in each second) until the adjustment has been
+ *   completed.  If the adjustment in delta is negative, then the clock is
+ *   slowed down in a similar fashion.
+ *
+ *   If a clock adjustment from an earlier adjtime() call is already in
+ *   progress at the time of a later adjtime() call, and delta is not NULL
+ *   for the later call, then the earlier adjustment is stopped, but any
+ *   already completed part of that adjustment is not undone.
+ *
+ *   If olddelta is not NULL, then the buffer that it points to is used to
+ *   return the amount of time remaining from any previous adjustment that
+ *   has not yet been completed.
+ *
+ *   NOTE: This is not a POSIX interface but derives from 4.3BSD, System V.
+ *   It is also supported for Linux compatibility.
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_CLOCK_TIMEKEEPING
+int adjtime(FAR const struct timeval *delta, FAR struct timeval *olddelta);
+#endif
+
 #undef EXTERN
 #if defined(__cplusplus)
 }

sched/Kconfig

@@ -167,6 +167,17 @@ config CLOCK_MONOTONIC
 
 		The value of the CLOCK_MONOTONIC clock cannot be set via clock_settime().
 
+config ARCH_HAVE_TIMEKEEPING
+	bool
+	default n
+
+config CLOCK_TIMEKEEPING
+	bool "Support timekeeping algorithms"
+	default n
+	depends on EXPERIMENTAL && ARCH_HAVE_TIMEKEEPING
+	---help---
+		CLOCK_TIMEKEEPING enables experimental time management algorithms.
+
 config JULIAN_TIME
 	bool "Enables Julian time conversions"
 	default n

sched/clock/Make.defs

@@ -38,6 +38,10 @@ CSRCS += clock_time2ticks.c clock_abstime2ticks.c clock_ticks2time.c
 CSRCS += clock_systimer.c clock_systimespec.c clock_timespec_add.c
 CSRCS += clock_timespec_subtract.c
 
+ifeq ($(CONFIG_CLOCK_TIMEKEEPING),y
+CSRCS += clock_timekeeping.c
+endif
+
 # Include clock build support
 
 DEPPATH += --dep-path clock

sched/clock/clock.h

@@ -79,7 +79,9 @@ extern volatile uint32_t g_system_timer;
 #  endif
 #endif
 
+#ifndef CONFIG_CLOCK_TIMEKEEPING
 extern struct timespec   g_basetime;
+#endif
 
 /********************************************************************************
  * Public Function Prototypes

sched/clock/clock_gettime.c

@@ -49,6 +49,9 @@
 #include <nuttx/arch.h>
 
 #include "clock/clock.h"
+#ifdef CONFIG_CLOCK_TIMEKEEPING
+#  include "clock/clock_timekeeping.h"
+#endif
 
 /****************************************************************************
  * Public Functions
@@ -90,7 +93,9 @@ int clock_gettime(clockid_t clock_id, struct timespec *tp)
        * reset.
        */
 
-#ifdef CONFIG_SCHED_TICKLESS
+#if defined(CONFIG_CLOCK_TIMEKEEPING)
+      ret = clock_timekeeping_get_monotonic_time(tp);
+#elif defined(CONFIG_SCHED_TICKLESS)
       ret = up_timer_gettime(tp);
 #else
       ret = clock_systimespec(tp);
@@ -113,7 +118,15 @@ int clock_gettime(clockid_t clock_id, struct timespec *tp)
        * last set.
        */
 
+#if defined(CONFIG_CLOCK_TIMEKEEPING)
+      ret = clock_timekeeping_get_wall_time(tp);
+#elif defined(CONFIG_SCHED_TICKLESS)
+      ret = up_timer_gettime(&ts);
+#else
       ret = clock_systimespec(&ts);
+#endif
+
+#ifndef CONFIG_CLOCK_TIMEKEEPING
       if (ret == OK)
         {
           /* Add the base time to this.  The base time is the time-of-day
@@ -138,6 +151,7 @@ int clock_gettime(clockid_t clock_id, struct timespec *tp)
           tp->tv_sec  = ts.tv_sec;
           tp->tv_nsec = ts.tv_nsec;
         }
+#endif /* CONFIG_CLOCK_TIMEKEEPING */
     }
   else
     {

sched/clock/clock_initialize.c

@@ -54,6 +54,9 @@
 #include <nuttx/time.h>
 
 #include "clock/clock.h"
+#ifdef CONFIG_CLOCK_TIMEKEEPING
+#  include "clock/clock_timekeeping.h"
+#endif
 
 /****************************************************************************
  * Pre-processor Definitions
@@ -172,10 +175,16 @@ static void clock_inittime(void)
 {
   /* (Re-)initialize the time value to match the RTC */
 
-  (void)clock_basetime(&g_basetime);
+#ifndef CONFIG_CLOCK_TIMEKEEPING
+#ifndef CONFIG_RTC_HIRES
+  clock_basetime(&g_basetime);
+#endif
 #ifndef CONFIG_SCHED_TICKLESS
   g_system_timer = 0;
 #endif
+#else
+  clock_inittimekeeping();
+#endif
 }
 
 /****************************************************************************

sched/clock/clock_settime.c

@@ -48,6 +48,9 @@
 #include <nuttx/irq.h>
 
 #include "clock/clock.h"
+#ifdef CONFIG_CLOCK_TIMEKEEPING
+#  include "clock/clock_timekeeping.h"
+#endif
 
 /****************************************************************************
  * Public Functions
@@ -76,6 +79,7 @@ int clock_settime(clockid_t clock_id, FAR const struct timespec *tp)
 
   if (clock_id == CLOCK_REALTIME)
     {
+#ifndef CONFIG_CLOCK_TIMEKEEPING
       /* Interrupts are disabled here so that the in-memory time
        * representation and the RTC setting will be as close as
        * possible.
@@ -123,6 +127,9 @@ int clock_settime(clockid_t clock_id, FAR const struct timespec *tp)
       sinfo("basetime=(%ld,%lu) bias=(%ld,%lu)\n",
             (long)g_basetime.tv_sec, (unsigned long)g_basetime.tv_nsec,
             (long)bias.tv_sec, (unsigned long)bias.tv_nsec);
+#else
+      ret = clock_timekeeping_set_wall_time(tp);
+#endif
     }
   else
     {

sched/clock/clock_systimer.c

@@ -83,7 +83,11 @@ systime_t clock_systimer(void)
 
   /* Get the time from the platform specific hardware */
 
+#ifndef CONFIG_CLOCK_TIMEKEEPING
   (void)up_timer_gettime(&ts);
+#else
+  (void)clock_timekeeping_get_monotonic_time(&ts);
+#endif
 
   /* Convert to a 64-bit value in microseconds, then in clock tick units */
 
@@ -96,7 +100,11 @@ systime_t clock_systimer(void)
 
   /* Get the time from the platform specific hardware */
 
+#ifndef CONFIG_CLOCK_TIMEKEEPING
   (void)up_timer_gettime(&ts);
+#else
+  (void)clock_timekeeping_get_monotonic_time(&ts);
+#endif
 
   /* Convert to a 64- then a 32-bit value */
 

sched/clock/clock_timekeeping.c

@@ -0,0 +1,329 @@
+/************************************************************************
+ * sched/clock/clock_timekeeping.c
+ *
+ *   Copyright (C) 2016 Gregory Nutt. All rights reserved.
+ *   Author:  Max Neklyudov <macscomp@gmail.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ************************************************************************/
+
+/************************************************************************
+ * Included Files
+ ************************************************************************/
+
+#include <nuttx/config.h>
+
+#ifdef CONFIG_CLOCK_TIMEKEEPING
+
+#include <sys/time.h>
+#include <stdint.h>
+#include <time.h>
+#include <errno.h>
+#include <debug.h>
+
+#include <nuttx/irq.h>
+#include <nuttx/arch.h>
+
+#include "clock/clock.h"
+
+/************************************************************************
+ * Pre-processor Definitions
+ ************************************************************************/
+
+#define NTP_MAX_ADJUST 500
+
+/**********************************************************************
+ * Private Data
+ **********************************************************************/
+
+static struct timespec g_clock_wall_time;
+static struct timespec g_clock_monotonic_time;
+static uint64_t        g_clock_last_counter;
+static uint64_t        g_clock_mask;
+static long            g_clock_adjust;
+
+/************************************************************************
+ * Private Functions
+ ************************************************************************/
+
+/************************************************************************
+ * Name: clock_get_current_time
+ ************************************************************************/
+
+static int clock_get_current_time(FAR struct timespec *ts,
+                                  FAR struct timespec *base)
+{
+  irqstate_t flags;
+  uint64_t counter;
+  uint64_t offset;
+  uint64_t nsec;
+  time_t sec;
+  int ret;
+
+  flags = enter_critical_section();
+
+  ret = up_timer_getcounter(&counter);
+  if (ret < 0)
+    {
+      goto errout_in_critical_section;
+    }
+
+  offset = (counter - g_clock_last_counter) & g_clock_mask;
+  nsec   = offset * NSEC_PER_TICK;
+  sec    = nsec   / NSEC_PER_SEC;
+  nsec  -= sec    * NSEC_PER_SEC;
+
+  nsec  += base->tv_nsec;
+  if (nsec > NSEC_PER_SEC)
+    {
+      nsec -= NSEC_PER_SEC;
+      sec += 1;
+    }
+
+  ts->tv_nsec = nsec;
+  ts->tv_sec = base->tv_sec + sec;
+
+errout_in_critical_section:
+  leave_critical_section(flags);
+  return ret;
+}
+
+/************************************************************************
+ * Public Functions
+ ************************************************************************/
+
+/************************************************************************
+ * Name: clock_timekeeping_get_monotonic_time
+ ************************************************************************/
+
+int clock_timekeeping_get_monotonic_time(FAR struct timespec *ts)
+{
+  return clock_get_current_time(ts, &g_clock_monotonic_time);
+}
+
+/************************************************************************
+ * Name: clock_timekeeping_get_wall_time
+ ************************************************************************/
+
+int clock_timekeeping_get_wall_time(FAR struct timespec *ts)
+{
+  return clock_get_current_time(ts, &g_clock_wall_time);
+}
+
+/************************************************************************
+ * Name: clock_timekeeping_set_wall_time
+ ************************************************************************/
+
+int clock_timekeeping_set_wall_time(FAR struct timespec *ts)
+{
+  irqstate_t flags;
+  uint64_t counter;
+  int ret;
+
+  flags = enter_critical_section();
+
+  ret = up_timer_getcounter(&counter);
+  if (ret < 0)
+    {
+      goto errout_in_critical_section;
+    }
+
+  g_clock_wall_time    = *ts;
+  g_clock_adjust       = 0;
+  g_clock_last_counter = counter;
+
+errout_in_critical_section:
+  leave_critical_section(flags);
+  return ret;
+}
+
+/****************************************************************************
+ * Name: adjtime
+ *
+ * Description:
+ *   The adjtime() function gradually adjusts the system clock (as returned
+ *   by gettimeofday(2)).  The amount of time by which the clock is to be
+ *   adjusted is specified in the structure pointed to by delta.
+ *
+ *   This structure has the following form:
+ *
+ *     struct timeval
+ *       {
+ *         time_t      tv_sec;     (seconds)
+ *         suseconds_t tv_usec;    (microseconds)
+ *       };
+ *
+ *   If the adjustment in delta is positive, then the system clock is
+ *   speeded up by some small percentage (i.e., by adding a small amount of
+ *   time to the clock value in each second) until the adjustment has been
+ *   completed.  If the adjustment in delta is negative, then the clock is
+ *   slowed down in a similar fashion.
+ *
+ *   If a clock adjustment from an earlier adjtime() call is already in
+ *   progress at the time of a later adjtime() call, and delta is not NULL
+ *   for the later call, then the earlier adjustment is stopped, but any
+ *   already completed part of that adjustment is not undone.
+ *
+ *   If olddelta is not NULL, then the buffer that it points to is used to
+ *   return the amount of time remaining from any previous adjustment that
+ *   has not yet been completed.
+ *
+ *   NOTE: This is not a POSIX interface but derives from 4.3BSD, System V.
+ *   It is also supported for Linux compatibility.
+ *
+ ****************************************************************************/
+
+int adjtime(FAR const struct timeval *delta, FAR struct timeval *olddelta)
+{
+  irqstate_t flags;
+  long adjust_usec;
+
+  if (!delta)
+    {
+      set_errno(EINVAL);
+      return -1;
+    }
+
+  flags = enter_critical_section();
+
+  adjust_usec = delta->tv_sec * USEC_PER_SEC + delta->tv_usec;
+
+  if (olddelta)
+    {
+      olddelta->tv_usec = g_clock_adjust;
+    }
+
+  g_clock_adjust = adjust_usec;
+
+  leave_critical_section(flags);
+
+  return OK;
+}
+
+/************************************************************************
+ * Name: clock_update_wall_time
+ ************************************************************************/
+
+void clock_update_wall_time(void)
+{
+  irqstate_t flags;
+  uint64_t counter;
+  uint64_t offset;
+  int64_t nsec;
+  time_t sec;
+  int ret;
+
+  flags = enter_critical_section();
+
+  ret = up_timer_getcounter(&counter);
+  if (ret < 0)
+    {
+      goto errout_in_critical_section;
+    }
+
+  offset = (counter - g_clock_last_counter) & g_clock_mask;
+  if (offset == 0)
+    {
+      goto errout_in_critical_section;
+    }
+
+  nsec  = offset * NSEC_PER_TICK;
+  sec   = nsec / NSEC_PER_SEC;
+  nsec -= sec * NSEC_PER_SEC;
+
+  g_clock_monotonic_time.tv_sec += sec;
+  g_clock_monotonic_time.tv_nsec += nsec;
+  if (g_clock_monotonic_time.tv_nsec > NSEC_PER_SEC)
+    {
+      g_clock_monotonic_time.tv_nsec -= NSEC_PER_SEC;
+      g_clock_monotonic_time.tv_sec += 1;
+    }
+
+  nsec += g_clock_wall_time.tv_nsec;
+  if (nsec > NSEC_PER_SEC)
+    {
+      nsec -= NSEC_PER_SEC;
+      sec += 1;
+    }
+
+  if (g_clock_adjust != 0 && sec > 0)
+    {
+      long adjust = NTP_MAX_ADJUST * (long)sec;
+      if (g_clock_adjust < adjust && g_clock_adjust > -adjust)
+        {
+          adjust = g_clock_adjust;
+        }
+
+      nsec += adjust * NSEC_PER_USEC;
+
+      while (nsec < 0)
+        {
+          nsec += NSEC_PER_SEC;
+          sec -= 1;
+        }
+
+      while (nsec > NSEC_PER_SEC)
+        {
+          nsec -= NSEC_PER_SEC;
+          sec += 1;
+        }
+    }
+
+  g_clock_wall_time.tv_sec += sec;
+  g_clock_wall_time.tv_nsec = (long)nsec;
+
+  g_clock_last_counter = counter;
+
+errout_in_critical_section:
+  leave_critical_section(flags);
+}
+
+/************************************************************************
+ * Name: clock_inittimekeeping
+ ************************************************************************/
+
+void clock_inittimekeeping(void)
+{
+  struct tm rtctime;
+
+  up_timer_getmask(&g_clock_mask);
+
+  /* Get the broken-errout_in_critical_section time from the date/time RTC. */
+
+  (void)up_rtc_getdatetime(&rtctime);
+
+  /* And use the broken-errout_in_critical_section time to initialize the system time */
+
+  g_clock_wall_time.tv_sec  = mktime(&rtctime);
+  g_clock_wall_time.tv_nsec = 0;
+
+  memset(&g_clock_monotonic_time, 0, sizeof(g_clock_monotonic_time));
+}
+
+#endif /* CONFIG_CLOCK_TIMEKEEPING */

sched/clock/clock_timekeeping.h

@@ -0,0 +1,62 @@
+/********************************************************************************
+ * sched/clock/clock_timekeeping.h
+ *
+ *   Copyright (C) 2016 Gregory Nutt. All rights reserved.
+ *   Author:  Max Neklyudov <macscomp@gmail.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ********************************************************************************/
+
+#ifndef __SCHED_CLOCK_CLOCK_TIMEKEEPING_H
+#define __SCHED_CLOCK_CLOCK_TIMEKEEPING_H
+
+/********************************************************************************
+ * Included Files
+ ********************************************************************************/
+
+#include <nuttx/config.h>
+#include <nuttx/compiler.h>
+
+#include <stdint.h>
+
+#include <nuttx/clock.h>
+
+/********************************************************************************
+ * Public Function Prototypes
+ ********************************************************************************/
+
+int clock_timekeeping_get_monotonic_time(FAR struct timespec *ts);
+int clock_timekeeping_get_wall_time(FAR struct timespec *ts);
+int clock_timekeeping_set_wall_time(FAR struct timespec *ts);
+
+void clock_update_wall_time(void);
+
+void clock_inittimekeeping(void);
+
+#endif /* __SCHED_CLOCK_CLOCK_TIMEKEEPING_H */

sched/sched/sched_processtimer.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * sched/sched/sched_processtimer.c
  *
- *   Copyright (C) 2007, 2009, 2014-2015 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007, 2009, 2014-2016 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -144,6 +144,12 @@ static inline void sched_process_scheduler(void)
 
 void sched_process_timer(void)
 {
+#ifdef CONFIG_CLOCK_TIMEKEEPING
+  /* Process wall time */
+
+  clock_update_wall_time();
+#endif
+
   /* Increment the system time (if in the link) */
 
 #ifdef CONFIG_HAVE_WEAKFUNCTIONS

sched/sched/sched_timerexpiration.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * sched/sched/sched_timerexpiration.c
  *
- *   Copyright (C) 2014-2015 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2014-2016 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -53,6 +53,10 @@
 #include "wdog/wdog.h"
 #include "clock/clock.h"
 
+#ifdef CONFIG_CLOCK_TIMEKEEPING
+# include "clock/clock_timekeeping.h"
+#endif
+
 #ifdef CONFIG_SCHED_TICKLESS
 
 /****************************************************************************
@@ -262,6 +266,12 @@ static unsigned int sched_timer_process(unsigned int ticks, bool noswitches)
   unsigned int rettime  = 0;
   unsigned int tmp;
 
+#ifdef CONFIG_CLOCK_TIMEKEEPING
+  /* Process wall time */
+
+  clock_update_wall_time();
+#endif
+
   /* Process watchdogs */
 
   tmp = wd_timer(ticks);

syscall/syscall.csv

@@ -1,4 +1,5 @@
 "_exit","unistd.h","","void","int"
+"adjtime","sys/time.h","defined(CONFIG_CLOCK_TIMEKEEPING)","int","FAR const struct timeval *","FAR struct timeval *"
 "aio_cancel","aio.h","defined(CONFIG_FS_AIO)","int","int","FAR struct aiocb *"
 "aio_fsync","aio.h","defined(CONFIG_FS_AIO)","int","int","FAR struct aiocb *"
 "aio_read","aio.h","defined(CONFIG_FS_AIO)","int","FAR struct aiocb *"

syscall/syscall_lookup.h

@@ -152,6 +152,9 @@ SYSCALL_LOOKUP(up_assert,                 2, STUB_up_assert)
   SYSCALL_LOOKUP(clock_getres,            2, STUB_clock_getres)
   SYSCALL_LOOKUP(clock_gettime,           2, STUB_clock_gettime)
   SYSCALL_LOOKUP(clock_settime,           2, STUB_clock_settime)
+#ifdef CONFIG_CLOCK_TIMEKEEPING
+  SYSCALL_LOOKUP(adjtime,                 2, STUB_adjtime)
+#endif
 
 /* The following are defined only if POSIX timers are supported */
 

syscall/syscall_stublookup.c

@@ -154,6 +154,7 @@ uintptr_t STUB_clock_systimer(int nbr);
 uintptr_t STUB_clock_getres(int nbr, uintptr_t parm1, uintptr_t parm2);
 uintptr_t STUB_clock_gettime(int nbr, uintptr_t parm1, uintptr_t parm2);
 uintptr_t STUB_clock_settime(int nbr, uintptr_t parm1, uintptr_t parm2);
+uintptr_t STUB_adjtime(int nbr, uintptr_t parm1, uintptr_t parm2);
 
 /* The following are defined only if POSIX timers are supported */