* [RESEND PATCH] pinctrl: mediatek: use spin lock in mtk_rmw
@ 2021-04-19 5:21 Tzung-Bi Shih
2021-04-19 8:31 ` Andy Shevchenko
0 siblings, 1 reply; 3+ messages in thread
From: Tzung-Bi Shih @ 2021-04-19 5:21 UTC (permalink / raw)
To: sean.wang, linus.walleij, matthias.bgg, zhiyong.tao, broonie
Cc: linux-mediatek, linux-gpio, linux-arm-kernel, alsa-devel, tzungbi
Commit 42a46434e9b1 ("pinctrl: add lock in mtk_rmw function.") uses
mutex lock in mtk_rmw. However the function is possible called from
atomic context.
For example call trace:
mutex_lock+0x28/0x64
mtk_rmw+0x38/0x80
mtk_hw_set_value+0x100/0x138
mtk_gpio_set+0x48/0x58
gpiod_set_raw_value_commit+0xf4/0x110
gpiod_set_value_nocheck+0x4c/0x80
gpiod_set_value+0x4c/0x6c
max98357a_daiops_trigger+0x8c/0x9c
soc_pcm_trigger+0x5c/0x10c
The max98357a_daiops_trigger() could run in either atomic or non-atomic
context. As a result, dmesg shows some similar messages: "BUG: sleeping
function called from invalid context at kernel/locking/mutex.c:254".
Uses spin lock in mtk_rmw instead.
Fixes: 42a46434e9b1 ("pinctrl: add lock in mtk_rmw function.")
Signed-off-by: Tzung-Bi Shih <tzungbi@google.com>
---
drivers/pinctrl/mediatek/pinctrl-moore.c | 2 +-
drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c | 4 ++--
drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.h | 2 +-
drivers/pinctrl/mediatek/pinctrl-paris.c | 2 +-
4 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/pinctrl/mediatek/pinctrl-moore.c b/drivers/pinctrl/mediatek/pinctrl-moore.c
index f77921957f15..3a4a23c40a71 100644
--- a/drivers/pinctrl/mediatek/pinctrl-moore.c
+++ b/drivers/pinctrl/mediatek/pinctrl-moore.c
@@ -619,7 +619,7 @@ int mtk_moore_pinctrl_probe(struct platform_device *pdev,
hw->nbase = hw->soc->nbase_names;
- mutex_init(&hw->lock);
+ spin_lock_init(&hw->lock);
/* Copy from internal struct mtk_pin_desc to register to the core */
pins = devm_kmalloc_array(&pdev->dev, hw->soc->npins, sizeof(*pins),
diff --git a/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c b/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c
index fcf7c3eeee4a..9ffe01a8ceca 100644
--- a/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c
+++ b/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c
@@ -58,14 +58,14 @@ void mtk_rmw(struct mtk_pinctrl *pctl, u8 i, u32 reg, u32 mask, u32 set)
{
u32 val;
- mutex_lock(&pctl->lock);
+ spin_lock(&pctl->lock);
val = mtk_r32(pctl, i, reg);
val &= ~mask;
val |= set;
mtk_w32(pctl, i, reg, val);
- mutex_unlock(&pctl->lock);
+ spin_unlock(&pctl->lock);
}
static int mtk_hw_pin_field_lookup(struct mtk_pinctrl *hw,
diff --git a/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.h b/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.h
index 65eac708a3b3..13836bb188b7 100644
--- a/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.h
+++ b/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.h
@@ -252,7 +252,7 @@ struct mtk_pinctrl {
struct mtk_pinctrl_group *groups;
const char **grp_names;
/* lock pin's register resource to avoid multiple threads issue*/
- struct mutex lock;
+ spinlock_t lock;
};
void mtk_rmw(struct mtk_pinctrl *pctl, u8 i, u32 reg, u32 mask, u32 set);
diff --git a/drivers/pinctrl/mediatek/pinctrl-paris.c b/drivers/pinctrl/mediatek/pinctrl-paris.c
index 48e823f6d293..85db2e4377f0 100644
--- a/drivers/pinctrl/mediatek/pinctrl-paris.c
+++ b/drivers/pinctrl/mediatek/pinctrl-paris.c
@@ -970,7 +970,7 @@ int mtk_paris_pinctrl_probe(struct platform_device *pdev,
hw->nbase = hw->soc->nbase_names;
- mutex_init(&hw->lock);
+ spin_lock_init(&hw->lock);
err = mtk_pctrl_build_state(pdev);
if (err) {
--
2.31.1.368.gbe11c130af-goog
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^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [RESEND PATCH] pinctrl: mediatek: use spin lock in mtk_rmw
2021-04-19 5:21 [RESEND PATCH] pinctrl: mediatek: use spin lock in mtk_rmw Tzung-Bi Shih
@ 2021-04-19 8:31 ` Andy Shevchenko
2021-04-19 9:36 ` Tzung-Bi Shih
0 siblings, 1 reply; 3+ messages in thread
From: Andy Shevchenko @ 2021-04-19 8:31 UTC (permalink / raw)
To: Tzung-Bi Shih
Cc: sean.wang, Linus Walleij, Matthias Brugger, Zhiyong Tao,
Mark Brown, moderated list:ARM/Mediatek SoC support,
open list:GPIO SUBSYSTEM, linux-arm Mailing List,
ALSA Development Mailing List
On Mon, Apr 19, 2021 at 8:32 AM Tzung-Bi Shih <tzungbi@google.com> wrote:
>
> Commit 42a46434e9b1 ("pinctrl: add lock in mtk_rmw function.") uses
> mutex lock in mtk_rmw. However the function is possible called from
> atomic context.
>
> For example call trace:
Please, shrink it to the necessary minimum.
> mutex_lock+0x28/0x64
> mtk_rmw+0x38/0x80
> mtk_hw_set_value+0x100/0x138
> mtk_gpio_set+0x48/0x58
> gpiod_set_raw_value_commit+0xf4/0x110
> gpiod_set_value_nocheck+0x4c/0x80
> gpiod_set_value+0x4c/0x6c
> max98357a_daiops_trigger+0x8c/0x9c
> soc_pcm_trigger+0x5c/0x10c
>
> The max98357a_daiops_trigger() could run in either atomic or non-atomic
> context. As a result, dmesg shows some similar messages: "BUG: sleeping
> function called from invalid context at kernel/locking/mutex.c:254".
>
> Uses spin lock in mtk_rmw instead.
It's nice, but now the question is, can you have this function be
called in a non-IRQ context concurrently with IRQ accessing registers?
--
With Best Regards,
Andy Shevchenko
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linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [RESEND PATCH] pinctrl: mediatek: use spin lock in mtk_rmw
2021-04-19 8:31 ` Andy Shevchenko
@ 2021-04-19 9:36 ` Tzung-Bi Shih
0 siblings, 0 replies; 3+ messages in thread
From: Tzung-Bi Shih @ 2021-04-19 9:36 UTC (permalink / raw)
To: Andy Shevchenko
Cc: sean.wang, Linus Walleij, Matthias Brugger, Zhiyong Tao,
Mark Brown, moderated list:ARM/Mediatek SoC support,
open list:GPIO SUBSYSTEM, linux-arm Mailing List,
ALSA Development Mailing List
On Mon, Apr 19, 2021 at 4:31 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
> On Mon, Apr 19, 2021 at 8:32 AM Tzung-Bi Shih <tzungbi@google.com> wrote:
> > For example call trace:
>
> Please, shrink it to the necessary minimum.
I'll snip the stack a bit in the next version.
> > Uses spin lock in mtk_rmw instead.
>
> It's nice, but now the question is, can you have this function be
> called in a non-IRQ context concurrently with IRQ accessing registers?
Fixed in v2. See
https://patchwork.ozlabs.org/project/linux-gpio/list/?series=239787 .
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^ permalink raw reply [flat|nested] 3+ messages in thread
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2021-04-19 8:31 ` Andy Shevchenko
2021-04-19 9:36 ` Tzung-Bi Shih
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