unified: implement k_uptime_{get,delta}()

Simple conversion from ticks for now.

Change-Id: Ib81fc738d45641a6a3a88d2adec1f3eb861f3f97
Signed-off-by: Benjamin Walsh <benjamin.walsh@windriver.com>

include/kernel.h

@@ -318,8 +318,57 @@ extern void k_timer_restart(struct k_timer *timer, int32_t duration,
 extern void k_timer_stop(struct k_timer *timer);
 extern int k_timer_test(struct k_timer *timer, void **data, int wait);
 extern int32_t k_timer_remaining_get(struct k_timer *timer);
+
+
+/**
+ * @brief Get the time elapsed since the system booted (uptime)
+ *
+ * @return The current uptime of the system in ms
+ */
+
 extern int64_t k_uptime_get(void);
+
+/**
+ * @brief Get the lower 32-bit of time elapsed since the system booted (uptime)
+ *
+ * This function is potentially less onerous in both the time it takes to
+ * execute, the interrupt latency it introduces and the amount of 64-bit math
+ * it requires than k_uptime_get(), but it only provides an uptime value of
+ * 32-bits. The user must handle possible rollovers/spillovers.
+ *
+ * At a rate of increment of 1000 per second, it rolls over approximately every
+ * 50 days.
+ *
+ * @return The current uptime of the system in ms
+ */
+
+extern uint32_t k_uptime_get_32(void);
+
+/**
+ * @brief Get the difference between a reference time and the current uptime
+ *
+ * @param reftime A pointer to a reference time. It is updated with the current
+ * uptime upon return.
+ *
+ * @return The delta between the reference time and the current uptime.
+ */
+
 extern int64_t k_uptime_delta(int64_t *reftime);
+
+/**
+ * @brief Get the difference between a reference time and the current uptime
+ *
+ * The 32-bit version of k_uptime_delta(). It has the same perks and issues as
+ * k_uptime_get_32().
+ *
+ * @param reftime A pointer to a reference time. It is updated with the current
+ * uptime upon return.
+ *
+ * @return The delta between the reference time and the current uptime.
+ */
+
+extern uint32_t k_uptime_delta_32(int64_t *reftime);
+
 extern bool k_timer_pool_is_empty(void);
 
 extern uint32_t k_cycle_get_32(void);

kernel/unified/sys_clock.c

@@ -56,6 +56,11 @@ uint32_t sys_tick_get_32(void)
 	return (uint32_t)_sys_clock_tick_count;
 }
 
+uint32_t k_uptime_get_32(void)
+{
+	return __ticks_to_ms(sys_tick_get_32());
+}
+
 /**
  *
  * @brief Return the current system tick count
@@ -79,6 +84,11 @@ int64_t sys_tick_get(void)
 	return tmp_sys_clock_tick_count;
 }
 
+int64_t k_uptime_get(void)
+{
+	return __ticks_to_ms(sys_tick_get());
+}
+
 /**
  *
  * @brief Return number of ticks since a reference time
@@ -145,6 +155,22 @@ uint32_t sys_tick_delta_32(int64_t *reftime)
 	return (uint32_t)_nano_tick_delta(reftime);
 }
 
+int64_t k_uptime_delta(int64_t *reftime)
+{
+	int64_t uptime, delta;
+
+	uptime = k_uptime_get();
+	delta = uptime - *reftime;
+	*reftime = uptime;
+
+	return delta;
+}
+
+uint32_t k_uptime_delta_32(int64_t *reftime)
+{
+	return (uint32_t)k_uptime_delta(reftime);
+}
+
 /* handle the expired timeouts in the nano timeout queue */
 
 #if defined(CONFIG_NANO_TIMEOUTS) || defined(CONFIG_NANO_TIMERS)