[PATCH v3 2/2] cyclic: reduce get_timer_us() calls inside hlist_for_each_entry_safe()

[Patrice Chotard <patrice.chotard@foss.st.com>]

On STM32MP157C-DK2, when using the "ums" command, in sleep_thread(),
ctrlc() is called every ~640ms which doesn't allows high reactivity when
user press CTRL+C in U-Boot console.

In sleep_thread() loop, ctrlc() is called every 200000 iterations.
But schedule is called on each loop iteration.

Optimize cyclic_run() in order to not call get_timer_us() on each entry.

This allow to save computation time :
  _ before : ctrlc() is called every ~640ms
  _ after  : ctrlc() is called every ~230ms

Signed-off-by: Rasmus Villemoes <rv@rasmusvillemoes.dk>
Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
Cc: Marek Vasut <marek.vasut@mailbox.org>
---
 common/cyclic.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/common/cyclic.c b/common/cyclic.c
index b37cd6d8ff0..573e715587d 100644
--- a/common/cyclic.c
+++ b/common/cyclic.c
@@ -67,26 +67,28 @@ static void cyclic_run(void)
 {
 	struct cyclic_info *cyclic;
 	struct hlist_node *tmp;
-	u64 now, cpu_time;
+	u64 now, after, cpu_time;
 
 	/* Prevent recursion */
 	if (gd->flags & GD_FLG_CYCLIC_RUNNING)
 		return;
 
 	gd->flags |= GD_FLG_CYCLIC_RUNNING;
+	now = get_timer_us(0);
 	hlist_for_each_entry_safe(cyclic, tmp, cyclic_get_list(), list) {
 		/*
 		 * Check if this cyclic function needs to get called, e.g.
 		 * do not call the cyclic func too often
 		 */
-		now = get_timer_us(0);
 		if (time_after_eq64(now, cyclic->next_call)) {
 			/* Call cyclic function and account it's cpu-time */
 			cyclic->next_call = now + cyclic->delay_us;
 			cyclic->func(cyclic);
+			after = get_timer_us(0);
 			cyclic->run_cnt++;
-			cpu_time = get_timer_us(0) - now;
+			cpu_time = after - now;
 			cyclic->cpu_time_us += cpu_time;
+			now = after;
 
 			/* Check if cpu-time exceeds max allowed time */
 			if ((cpu_time > CONFIG_CYCLIC_MAX_CPU_TIME_US) &&

-- 
2.43.0