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

2021-04-19 Thread Daniel Lezcano 
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 
> 
> ---
>  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/

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

2021-04-16 Thread Hsin-Yi Wang 
On Fri, Apr 9, 2021 at 5:22 PM 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 
>

Tested-by: Hsin-Yi Wang 

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 1701.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: GW
  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




> ---
>  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
>

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

2021-04-09 Thread Fengquan Chen 
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 

---
 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