[PATCH v2] pinctrl: mediatek: use spin lock in mtk_rmw
Tzung-Bi Shih
tzungbi at google.com
Mon Apr 19 10:34:49 BST 2021
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
[snip]
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 at google.com>
---
Changes from v1[1]:
- Snip call trace.
- Use _irqsave and _irqrestore version of spin lock.
[1]: https://patchwork.ozlabs.org/project/linux-gpio/list/?series=239749
drivers/pinctrl/mediatek/pinctrl-moore.c | 2 +-
drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c | 5 +++--
drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.h | 2 +-
drivers/pinctrl/mediatek/pinctrl-paris.c | 2 +-
4 files changed, 6 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..fc79b3a7a188 100644
--- a/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c
+++ b/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c
@@ -57,15 +57,16 @@ static u32 mtk_r32(struct mtk_pinctrl *pctl, u8 i, u32 reg)
void mtk_rmw(struct mtk_pinctrl *pctl, u8 i, u32 reg, u32 mask, u32 set)
{
u32 val;
+ unsigned long flags;
- mutex_lock(&pctl->lock);
+ spin_lock_irqsave(&pctl->lock, flags);
val = mtk_r32(pctl, i, reg);
val &= ~mask;
val |= set;
mtk_w32(pctl, i, reg, val);
- mutex_unlock(&pctl->lock);
+ spin_unlock_irqrestore(&pctl->lock, flags);
}
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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