SAMV7: Add support for CONFIG_SCHED_TICKLESS_LIMIT_MAX_SLEEP

arch/arm/Kconfig

@@ -190,6 +190,7 @@ config ARCH_CHIP_SAMV7
 	select ARCH_CORTEXM7
 	select ARCH_HAVE_MPU
 	select ARCH_HAVE_RAMFUNCS
+	select ARCH_HAVE_TICKLESS
 	select ARMV7M_HAVE_STACKCHECK
 	---help---
 		Atmel SAMV7 (ARM Cortex-M7) architectures

arch/arm/src/sama5/sam_tickless.c

@@ -243,6 +243,9 @@ static void sam_oneshot_handler(void *arg)
 
 void up_timer_initialize(void)
 {
+#ifdef CONFIG_SCHED_TICKLESS_LIMIT_MAX_SLEEP
+  uint64_t max_delay;
+#endif
   int ret;
 
   /* Initialize the one-shot timer */
@@ -256,6 +259,29 @@ void up_timer_initialize(void)
       PANIC();
     }
 
+#ifdef CONFIG_SCHED_TICKLESS_LIMIT_MAX_SLEEP
+  /* Get the maximum delay of the one-shot timer in microseconds */
+
+  ret = sam_oneshot_max_delay(&g_tickless.oneshot, &max_delay);
+  if (ret < 0)
+    {
+      tclldbg("ERROR: sam_oneshot_max_delay failed\n");
+      PANIC();
+    }
+
+  /* Convert this to configured clock ticks for use by the OS timer logic */
+
+  max_delay /= CONFIG_USEC_PER_TICK;
+  if (max_delay > (uint64_t)UINT32_MAX)
+    {
+      g_oneshot_maxticks = UINT32_MAX;
+    }
+  else
+    {
+      g_oneshot_maxticks = (uint32_t)max_delay;
+    }
+#endif
+
   /* Initialize the free-running timer */
 
   ret = sam_freerun_initialize(&g_tickless.freerun,

arch/arm/src/samv7/sam_oneshot.c

@@ -467,7 +467,7 @@ int sam_oneshot_cancel(struct sam_oneshot_s *oneshot, struct timespec *ts)
  *
  ****************************************************************************/
 
-#if 0 /* Not used */
+#ifdef CONFIG_SCHED_TICKLESS_LIMIT_MAX_SLEEP
 int sam_oneshot_max_delay(struct sam_oneshot_s *oneshot, uint64_t *usec)
 {
   DEBUGASSERT(oneshot && usec);

arch/arm/src/samv7/sam_oneshot.h

@@ -141,7 +141,7 @@ int sam_oneshot_initialize(struct sam_oneshot_s *oneshot, int chan,
  *
  ****************************************************************************/
 
-#if 0 /* Not used */
+#ifdef CONFIG_SCHED_TICKLESS_LIMIT_MAX_SLEEP
 int sam_oneshot_max_delay(struct sam_oneshot_s *oneshot, uint64_t *usec);
 #endif