linux-kernel - [tip: timers/clocksource] clocksource/drivers/timer-rtl-otto: Do not interfere with interrupts

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Message-ID: <175883597505.709179.7983843522537898239.tip-bot2@tip-bot2>
Date: Thu, 25 Sep 2025 21:32:55 -0000
From: "tip-bot2 for Markus Stockhausen" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Markus Stockhausen <markus.stockhausen@....de>,
 Daniel Lezcano <daniel.lezcano@...aro.org>,
 Stephen Howell <howels@...thatwemight.be>, bjorn@...k.no, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject: [tip: timers/clocksource] clocksource/drivers/timer-rtl-otto: Do not
 interfere with interrupts

The following commit has been merged into the timers/clocksource branch of tip:

Commit-ID:     c445bffbf28f721e05d0ce06895045fc62aaff7c
Gitweb:        https://git.kernel.org/tip/c445bffbf28f721e05d0ce06895045fc62aaff7c
Author:        Markus Stockhausen <markus.stockhausen@....de>
AuthorDate:    Mon, 04 Aug 2025 04:03:27 -04:00
Committer:     Daniel Lezcano <daniel.lezcano@...aro.org>
CommitterDate: Tue, 23 Sep 2025 12:41:11 +02:00

clocksource/drivers/timer-rtl-otto: Do not interfere with interrupts

During normal operation the timers are reprogrammed including an
interrupt acknowledgement. This has no effect as the whole timer
is setup from scratch afterwards. Especially in an interrupt this
has already been done by rttm_timer_interrupt().

Change the behaviour as follows:

- Use rttm_disable_timer() during reprogramming
- Keep rttm_stop_timer() for all other use cases.

Downstream has already tested and confirmed a patch. See
https://github.com/openwrt/openwrt/pull/19468
https://forum.openwrt.org/t/support-for-rtl838x-based-managed-switches/57875/3788

Signed-off-by: Markus Stockhausen <markus.stockhausen@....de>
Signed-off-by: Daniel Lezcano <daniel.lezcano@...aro.org>
Tested-by: Stephen Howell <howels@...thatwemight.be>
Tested-by: Bjørn Mork <bjorn@...k.no>
Link: https://lore.kernel.org/r/20250804080328.2609287-4-markus.stockhausen@gmx.de
---
 drivers/clocksource/timer-rtl-otto.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/clocksource/timer-rtl-otto.c b/drivers/clocksource/timer-rtl-otto.c
index 48ba116..42f702a 100644
--- a/drivers/clocksource/timer-rtl-otto.c
+++ b/drivers/clocksource/timer-rtl-otto.c
@@ -141,7 +141,7 @@ static int rttm_next_event(unsigned long delta, struct clock_event_device *clkev
 
 	RTTM_DEBUG(to->of_base.base);
 	rttm_bounce_timer(to->of_base.base, RTTM_CTRL_COUNTER);
-	rttm_stop_timer(to->of_base.base);
+	rttm_disable_timer(to->of_base.base);
 	rttm_set_period(to->of_base.base, delta);
 	rttm_start_timer(to, RTTM_CTRL_COUNTER);
 
@@ -154,7 +154,7 @@ static int rttm_state_oneshot(struct clock_event_device *clkevt)
 
 	RTTM_DEBUG(to->of_base.base);
 	rttm_bounce_timer(to->of_base.base, RTTM_CTRL_COUNTER);
-	rttm_stop_timer(to->of_base.base);
+	rttm_disable_timer(to->of_base.base);
 	rttm_set_period(to->of_base.base, RTTM_TICKS_PER_SEC / HZ);
 	rttm_start_timer(to, RTTM_CTRL_COUNTER);
 
@@ -167,7 +167,7 @@ static int rttm_state_periodic(struct clock_event_device *clkevt)
 
 	RTTM_DEBUG(to->of_base.base);
 	rttm_bounce_timer(to->of_base.base, RTTM_CTRL_TIMER);
-	rttm_stop_timer(to->of_base.base);
+	rttm_disable_timer(to->of_base.base);
 	rttm_set_period(to->of_base.base, RTTM_TICKS_PER_SEC / HZ);
 	rttm_start_timer(to, RTTM_CTRL_TIMER);