diff mbox series

[v4,1/1] clocksource/drivers/timer-mediatek: optimize systimer irq clear flow on shutdown

Message ID 1617960162-1988-2-git-send-email-Fengquan.Chen@mediatek.com (mailing list archive)
State New
Headers show
Series [v4,1/1] clocksource/drivers/timer-mediatek: optimize systimer irq clear flow on shutdown | expand

Commit Message

Fengquan Chen April 9, 2021, 9:22 a.m. UTC
mtk_syst_clkevt_shutdown is called after irq disabled in suspend flow,
clear any pending systimer irq when shutdown to avoid suspend aborted
due to timer irq pending

Also as for systimer in mediatek socs, there must be firstly enable
timer before clear systimer irq

Fixes: e3af677607d9("clocksource/drivers/timer-mediatek: Add support for system timer")
Signed-off-by: Fengquan Chen <fengquan.chen@mediatek.com>

---
 drivers/clocksource/timer-mediatek.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

Comments

Hsin-Yi Wang April 16, 2021, 10:47 a.m. UTC | #1
On Fri, Apr 9, 2021 at 5:22 PM Fengquan Chen <Fengquan.Chen@mediatek.com> wrote:
>
> mtk_syst_clkevt_shutdown is called after irq disabled in suspend flow,
> clear any pending systimer irq when shutdown to avoid suspend aborted
> due to timer irq pending
>
> Also as for systimer in mediatek socs, there must be firstly enable
> timer before clear systimer irq
>
> Fixes: e3af677607d9("clocksource/drivers/timer-mediatek: Add support for system timer")
> Signed-off-by: Fengquan Chen <fengquan.chen@mediatek.com>
>

Tested-by: Hsin-Yi Wang <hsinyi@chromium.org>

Tested on a mt8183 device. This patch solves an issue that device
would hang on resume during genpd_resume_noirq:

[  724.342834] mtk-smi-larb 17010000.larb: genpd_resume_noirq+0x0/0xd0
returned 0 after 976593 usecs
[  724.351721] mtk-smi-larb 1a001000.larb: calling
genpd_resume_noirq+0x0/0xd0 @ 6629, parent: soc
[  736.845047] Kernel panic - not syncing: Watchdog detected hard
LOCKUP on cpu 3
[  736.852268] CPU: 2 PID: 0 Comm: swapper/2 Tainted: G        W
  5.10.26 #17
[  736.859743] Hardware name: MediaTek krane sku176 board (DT)
[  736.865309] Call trace:
[  736.867756]  dump_backtrace+0x0/0x1bc
[  736.871415]  show_stack+0x20/0x2c
[  736.874728]  dump_stack+0xc0/0x11c
[  736.878124]  panic+0x174/0x378
[  736.881178]  watchdog_check_hardlockup+0x11c/0x124
[  736.885963]  watchdog_timer_fn+0x70/0x274
<snip>



> ---
>  drivers/clocksource/timer-mediatek.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/clocksource/timer-mediatek.c b/drivers/clocksource/timer-mediatek.c
> index 9318edc..6461fd3 100644
> --- a/drivers/clocksource/timer-mediatek.c
> +++ b/drivers/clocksource/timer-mediatek.c
> @@ -60,9 +60,9 @@
>   * SYST_CON_EN: Clock enable. Shall be set to
>   *   - Start timer countdown.
>   *   - Allow timeout ticks being updated.
> - *   - Allow changing interrupt functions.
> + *   - Allow changing interrupt status,like clear irq pending.
>   *
> - * SYST_CON_IRQ_EN: Set to allow interrupt.
> + * SYST_CON_IRQ_EN: Set to enable interrupt.
>   *
>   * SYST_CON_IRQ_CLR: Set to clear interrupt.
>   */
> @@ -75,6 +75,7 @@
>  static void mtk_syst_ack_irq(struct timer_of *to)
>  {
>         /* Clear and disable interrupt */
> +       writel(SYST_CON_EN, SYST_CON_REG(to));
>         writel(SYST_CON_IRQ_CLR | SYST_CON_EN, SYST_CON_REG(to));
>  }
>
> @@ -111,6 +112,9 @@ static int mtk_syst_clkevt_next_event(unsigned long ticks,
>
>  static int mtk_syst_clkevt_shutdown(struct clock_event_device *clkevt)
>  {
> +       /* Clear any irq */
> +       mtk_syst_ack_irq(to_timer_of(clkevt));
> +
>         /* Disable timer */
>         writel(0, SYST_CON_REG(to_timer_of(clkevt)));
>
> --
> 1.8.1.1.dirty
>
Daniel Lezcano April 19, 2021, 8:44 a.m. UTC | #2
On 09/04/2021 11:22, Fengquan Chen wrote:
> mtk_syst_clkevt_shutdown is called after irq disabled in suspend flow,
> clear any pending systimer irq when shutdown to avoid suspend aborted
> due to timer irq pending
> 
> Also as for systimer in mediatek socs, there must be firstly enable
> timer before clear systimer irq
> 
> Fixes: e3af677607d9("clocksource/drivers/timer-mediatek: Add support for system timer")
> Signed-off-by: Fengquan Chen <fengquan.chen@mediatek.com>
> 
> ---
>  drivers/clocksource/timer-mediatek.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/clocksource/timer-mediatek.c b/drivers/clocksource/timer-mediatek.c
> index 9318edc..6461fd3 100644
> --- a/drivers/clocksource/timer-mediatek.c
> +++ b/drivers/clocksource/timer-mediatek.c
> @@ -60,9 +60,9 @@
>   * SYST_CON_EN: Clock enable. Shall be set to
>   *   - Start timer countdown.
>   *   - Allow timeout ticks being updated.
> - *   - Allow changing interrupt functions.
> + *   - Allow changing interrupt status,like clear irq pending.
>   *
> - * SYST_CON_IRQ_EN: Set to allow interrupt.
> + * SYST_CON_IRQ_EN: Set to enable interrupt.
>   *
>   * SYST_CON_IRQ_CLR: Set to clear interrupt.
>   */
> @@ -75,6 +75,7 @@
>  static void mtk_syst_ack_irq(struct timer_of *to)
>  {
>  	/* Clear and disable interrupt */
> +	writel(SYST_CON_EN, SYST_CON_REG(to));
>  	writel(SYST_CON_IRQ_CLR | SYST_CON_EN, SYST_CON_REG(to));
>  }

IIRC, there is a hardware issue here. If it is the case, please describe
it and refer to an errata if any.

Also Evan Benn commented your code and asked a couple of questions [1],
please answer before reposting a new version.

Comments ignored == patch ignored

> @@ -111,6 +112,9 @@ static int mtk_syst_clkevt_next_event(unsigned long ticks,
>  
>  static int mtk_syst_clkevt_shutdown(struct clock_event_device *clkevt)
>  {
> +	/* Clear any irq */
> +	mtk_syst_ack_irq(to_timer_of(clkevt));
> +
>  	/* Disable timer */
>  	writel(0, SYST_CON_REG(to_timer_of(clkevt)));

Please check out the patch sent by Evan Benn [2], if you agree, ack it.

Thanks

  -- Daniel

[1] https://patchwork.kernel.org/comment/24059277/
[2]
https://lore.kernel.org/linux-arm-kernel/20210412132200.v3.1.I1d9917047de06715da16e1620759f703fcfdcbcb@changeid/
Fengquan Chen April 21, 2021, 10:27 a.m. UTC | #3
On Mon, 2021-04-19 at 10:44 +0200, Daniel Lezcano wrote:
> On 09/04/2021 11:22, Fengquan Chen wrote:
> > mtk_syst_clkevt_shutdown is called after irq disabled in suspend flow,
> > clear any pending systimer irq when shutdown to avoid suspend aborted
> > due to timer irq pending
> > 
> > Also as for systimer in mediatek socs, there must be firstly enable
> > timer before clear systimer irq
> > 
> > Fixes: e3af677607d9("clocksource/drivers/timer-mediatek: Add support for system timer")
> > Signed-off-by: Fengquan Chen <fengquan.chen@mediatek.com>
> > 
> > ---
> >  drivers/clocksource/timer-mediatek.c | 8 ++++++--
> >  1 file changed, 6 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/clocksource/timer-mediatek.c b/drivers/clocksource/timer-mediatek.c
> > index 9318edc..6461fd3 100644
> > --- a/drivers/clocksource/timer-mediatek.c
> > +++ b/drivers/clocksource/timer-mediatek.c
> > @@ -60,9 +60,9 @@
> >   * SYST_CON_EN: Clock enable. Shall be set to
> >   *   - Start timer countdown.
> >   *   - Allow timeout ticks being updated.
> > - *   - Allow changing interrupt functions.
> > + *   - Allow changing interrupt status,like clear irq pending.
> >   *
> > - * SYST_CON_IRQ_EN: Set to allow interrupt.
> > + * SYST_CON_IRQ_EN: Set to enable interrupt.
> >   *
> >   * SYST_CON_IRQ_CLR: Set to clear interrupt.
> >   */
> > @@ -75,6 +75,7 @@
> >  static void mtk_syst_ack_irq(struct timer_of *to)
> >  {
> >  	/* Clear and disable interrupt */
> > +	writel(SYST_CON_EN, SYST_CON_REG(to));
> >  	writel(SYST_CON_IRQ_CLR | SYST_CON_EN, SYST_CON_REG(to));
> >  }
> 
> IIRC, there is a hardware issue here. If it is the case, please describe
> it and refer to an errata if any.

Thanks for review.
here is just a hw config flow limitation, not a bug.

> 
> Also Evan Benn commented your code and asked a couple of questions [1],
> please answer before reposting a new version.
> 
> Comments ignored == patch ignored

Thanks. i have answered by mail before, but it didn't uploaded to the
list. has been uploaded ok now.

> 
> > @@ -111,6 +112,9 @@ static int mtk_syst_clkevt_next_event(unsigned long ticks,
> >  
> >  static int mtk_syst_clkevt_shutdown(struct clock_event_device *clkevt)
> >  {
> > +	/* Clear any irq */
> > +	mtk_syst_ack_irq(to_timer_of(clkevt));
> > +
> >  	/* Disable timer */
> >  	writel(0, SYST_CON_REG(to_timer_of(clkevt)));
> 
> Please check out the patch sent by Evan Benn [2], if you agree, ack it.
> 

Thanks

agree

> Thanks
> 
>   -- Daniel
> 
> [1] https://patchwork.kernel.org/comment/24059277/
> [2]
> https://lore.kernel.org/linux-arm-kernel/20210412132200.v3.1.I1d9917047de06715da16e1620759f703fcfdcbcb@changeid/
>
diff mbox series

Patch

diff --git a/drivers/clocksource/timer-mediatek.c b/drivers/clocksource/timer-mediatek.c
index 9318edc..6461fd3 100644
--- a/drivers/clocksource/timer-mediatek.c
+++ b/drivers/clocksource/timer-mediatek.c
@@ -60,9 +60,9 @@ 
  * SYST_CON_EN: Clock enable. Shall be set to
  *   - Start timer countdown.
  *   - Allow timeout ticks being updated.
- *   - Allow changing interrupt functions.
+ *   - Allow changing interrupt status,like clear irq pending.
  *
- * SYST_CON_IRQ_EN: Set to allow interrupt.
+ * SYST_CON_IRQ_EN: Set to enable interrupt.
  *
  * SYST_CON_IRQ_CLR: Set to clear interrupt.
  */
@@ -75,6 +75,7 @@ 
 static void mtk_syst_ack_irq(struct timer_of *to)
 {
 	/* Clear and disable interrupt */
+	writel(SYST_CON_EN, SYST_CON_REG(to));
 	writel(SYST_CON_IRQ_CLR | SYST_CON_EN, SYST_CON_REG(to));
 }
 
@@ -111,6 +112,9 @@  static int mtk_syst_clkevt_next_event(unsigned long ticks,
 
 static int mtk_syst_clkevt_shutdown(struct clock_event_device *clkevt)
 {
+	/* Clear any irq */
+	mtk_syst_ack_irq(to_timer_of(clkevt));
+
 	/* Disable timer */
 	writel(0, SYST_CON_REG(to_timer_of(clkevt)));