timer: handle perf count overflow

clock_getcycle always returns an incremented cycle value
If the hardware does not support perf event it will use arch_alarm's up_perf_gettime

Signed-off-by: yinshengkai <yinshengkai@xiaomi.com>

include/nuttx/clock.h

@@ -663,6 +663,24 @@ struct timer_lowerhalf_s;
 void nxsched_period_extclk(FAR struct timer_lowerhalf_s *lower);
 #endif
 
+/****************************************************************************
+ * perf_gettime
+ ****************************************************************************/
+
+clock_t perf_gettime(void);
+
+/****************************************************************************
+ * perf_convert
+ ****************************************************************************/
+
+void perf_convert(clock_t elapsed, FAR struct timespec *ts);
+
+/****************************************************************************
+ * perf_gettfreq
+ ****************************************************************************/
+
+unsigned long perf_getfreq(void);
+
 #undef EXTERN
 #ifdef __cplusplus
 }

sched/Kconfig

@@ -283,6 +283,16 @@ config PREALLOC_TIMERS
 		pool of preallocated timer structures to minimize dynamic allocations.  Set to
 		zero for all dynamic allocations.
 
+config PERF_OVERFLOW_CORRECTION
+	bool "Compensate perf count overflow"
+	depends on SYSTEM_TIME64 && (ALARM_ARCH || TIMER_ARCH || ARCH_PERF_EVENTS)
+	default n
+	---help---
+		If this option is enabled, then the perf event will be enabled
+		by default.
+		When enabled, it will always return an increasing count value to
+		avoid overflow on 32-bit platforms.
+
 endmenu # Clocks and Timers
 
 menu "Tasks and Scheduling"

sched/clock/CMakeLists.txt

@@ -20,6 +20,7 @@
 
 set(SRCS
     clock.c
+    clock_perf.c
     clock_initialize.c
     clock_settime.c
     clock_gettime.c

sched/clock/Make.defs

@@ -20,6 +20,7 @@
 
 CSRCS += clock.c clock_initialize.c clock_settime.c clock_gettime.c
 CSRCS += clock_abstime2ticks.c clock_systime_ticks.c clock_systime_timespec.c
+CSRCS += clock_perf.c
 
 ifeq ($(CONFIG_CLOCK_TIMEKEEPING),y)
 CSRCS += clock_timekeeping.c

sched/clock/clock.h

@@ -94,4 +94,10 @@ int  clock_abstime2ticks(clockid_t clockid,
                          FAR const struct timespec *abstime,
                          FAR sclock_t *ticks);
 
+/****************************************************************************
+ * perf_init
+ ****************************************************************************/
+
+void perf_init(void);
+
 #endif /* __SCHED_CLOCK_CLOCK_H */

sched/clock/clock_initialize.c

@@ -237,6 +237,8 @@ void clock_initialize(void)
 
 #endif
 
+  perf_init();
+
   sched_trace_end();
 }
 

sched/clock/clock_perf.c

@@ -0,0 +1,203 @@
+/****************************************************************************
+ * sched/clock/clock_perf.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <stdint.h>
+
+#include <nuttx/clock.h>
+#include <nuttx/arch.h>
+#include <nuttx/wdog.h>
+
+#if defined(CONFIG_PERF_OVERFLOW_CORRECTION) && ULONG_MAX != UINT64_MAX
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+struct perf_s
+{
+  struct wdog_s wdog;
+  unsigned long last;
+  unsigned long overflow;
+};
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+static struct perf_s g_perf;
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * perf_update
+ ****************************************************************************/
+
+static void perf_update(wdparm_t arg)
+{
+  clock_t tick = (clock_t)LONG_MAX * TICK_PER_SEC / up_perf_getfreq();
+
+  perf_gettime();
+  wd_start((FAR struct wdog_s *)arg, tick, perf_update, arg);
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * perf_init
+ ****************************************************************************/
+
+void perf_init(void)
+{
+  FAR struct perf_s *perf = &g_perf;
+  clock_t tick = (clock_t)LONG_MAX * TICK_PER_SEC / up_perf_getfreq();
+
+  perf->last = up_perf_gettime();
+
+  /* Periodic check for overflow */
+
+  wd_start(&perf->wdog, tick, perf_update, (wdparm_t)perf);
+}
+
+/****************************************************************************
+ * perf_gettime
+ ****************************************************************************/
+
+clock_t perf_gettime(void)
+{
+  FAR struct perf_s *perf = &g_perf;
+  unsigned long now = up_perf_gettime();
+
+  /* Check if overflow */
+
+  if (now < perf->last)
+    {
+      perf->overflow++;
+    }
+
+  perf->last = now;
+  return (clock_t)now | (clock_t)perf->overflow << 32;
+}
+
+/****************************************************************************
+ * perf_convert
+ ****************************************************************************/
+
+void perf_convert(clock_t elapsed, FAR struct timespec *ts)
+{
+  unsigned long freq = up_perf_getfreq();
+
+  ts->tv_sec  = elapsed / freq;
+  elapsed -= ts->tv_sec * freq;
+  ts->tv_nsec = NSEC_PER_SEC * elapsed / freq;
+}
+
+/****************************************************************************
+ * perf_getfreq
+ ****************************************************************************/
+
+unsigned long perf_getfreq(void)
+{
+  return up_perf_getfreq();
+}
+
+#elif defined(CONFIG_ALARM_ARCH) || defined (CONFIG_TIMER_ARCH) || \
+      defined(CONFIG_ARCH_PERF_EVENTS)
+
+/****************************************************************************
+ * perf_init
+ ****************************************************************************/
+
+void perf_init(void)
+{
+}
+
+/****************************************************************************
+ * perf_gettime
+ ****************************************************************************/
+
+clock_t perf_gettime(void)
+{
+  return up_perf_gettime();
+}
+
+/****************************************************************************
+ * perf_convert
+ ****************************************************************************/
+
+void perf_convert(clock_t elapsed, FAR struct timespec *ts)
+{
+  up_perf_convert(elapsed, ts);
+}
+
+/****************************************************************************
+ * perf_getfreq
+ ****************************************************************************/
+
+unsigned long perf_getfreq(void)
+{
+  return up_perf_getfreq();
+}
+
+#else
+
+/****************************************************************************
+ * perf_init
+ ****************************************************************************/
+
+void perf_init(void)
+{
+}
+
+/****************************************************************************
+ * perf_gettime
+ ****************************************************************************/
+
+clock_t perf_gettime(void)
+{
+  return clock_systime_ticks();
+}
+
+/****************************************************************************
+ * perf_convert
+ ****************************************************************************/
+
+void perf_convert(clock_t elapsed, FAR struct timespec *ts)
+{
+  clock_ticks2time(elapsed, ts);
+}
+
+/****************************************************************************
+ * perf_getfreq
+ ****************************************************************************/
+
+unsigned long perf_getfreq(void)
+{
+  return TICK_PER_SEC;
+}
+
+#endif