[PATCH] clocksource: kona: avoid bogus warning

From: Arnd Bergmann
Date: Mon Jun 13 2016 - 16:39:45 EST


I could not figure out why, but gcc cannot prove that the
kona_timer_init function always initializes its two outputs,
and we get a warning for the use of the 'lsw' variable later,
which is obviously correct.

drivers/clocksource/bcm_kona_timer.c: In function 'kona_timer_init':
drivers/clocksource/bcm_kona_timer.c:119:13: error: 'lsw' may be used uninitialized in this function [-Werror=maybe-uninitialized]

Slightly reordering the loop makes the warning disappear, after
it becomes more obvious to the compiler that the loop is
always entered on the first iteration.

Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
drivers/clocksource/bcm_kona_timer.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/clocksource/bcm_kona_timer.c b/drivers/clocksource/bcm_kona_timer.c
index 70d9c1e482dd..bbbfb03b46dd 100644
--- a/drivers/clocksource/bcm_kona_timer.c
+++ b/drivers/clocksource/bcm_kona_timer.c
@@ -69,7 +69,7 @@ static void kona_timer_disable_and_clear(void __iomem *base)
static void
kona_timer_get_counter(void __iomem *timer_base, uint32_t *msw, uint32_t *lsw)
{
- int loop_limit = 4;
+ int loop_limit = 3;

/*
* Read 64-bit free running counter
@@ -83,12 +83,12 @@ kona_timer_get_counter(void __iomem *timer_base, uint32_t *msw, uint32_t *lsw)
* if new hi-word is equal to previously read hi-word then stop.
*/

- while (--loop_limit) {
+ do {
*msw = readl(timer_base + KONA_GPTIMER_STCHI_OFFSET);
*lsw = readl(timer_base + KONA_GPTIMER_STCLO_OFFSET);
if (*msw == readl(timer_base + KONA_GPTIMER_STCHI_OFFSET))
break;
- }
+ } while (--loop_limit);
if (!loop_limit) {
pr_err("bcm_kona_timer: getting counter failed.\n");
pr_err(" Timer will be impacted\n");
--
2.7.0