[][kernel][pinctrl][Backport spinlock for mtk_rmw]
[Description]
Add spinlock mechanism for mtk_rmw api.
1. When multiple threads operate on the same register resource
which include multiple pins, it will make the register resource
wrong to control. So we add spinlock to avoid this case.
[Release-log]
This patch adds spinlock mechanism to protect mtk_rmw. Without it,
you may suffer from some unexpected problems such as race conidtion
while interrupt occured. And this will lead to pin setting fail.
Hence, we strongly recommand you to merge this patch in your code
base.
Change-Id: I1128dc16cb683b89c2cd9f9138f32552abb00400
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/7962757
diff --git a/target/linux/mediatek/patches-5.4/999-1033-backport-pinctrl-spinlock.patch b/target/linux/mediatek/patches-5.4/999-1033-backport-pinctrl-spinlock.patch
new file mode 100644
index 0000000..875bd7b
--- /dev/null
+++ b/target/linux/mediatek/patches-5.4/999-1033-backport-pinctrl-spinlock.patch
@@ -0,0 +1,29 @@
+--- a/drivers/pinctrl/mediatek/pinctrl-moore.c
++++ b/drivers/pinctrl/mediatek/pinctrl-moore.c
+@@ -662,6 +662,7 @@ int mtk_moore_pinctrl_probe(struct platf
+ }
+
+ hw->nbase = hw->soc->nbase_names;
++ 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),
+--- a/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c
++++ b/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c
+@@ -55,11 +55,16 @@ static u32 mtk_r32(struct mtk_pinctrl *p
+ void mtk_rmw(struct mtk_pinctrl *pctl, u8 i, u32 reg, u32 mask, u32 set)
+ {
+ u32 val;
++ unsigned long flags;
++
++ spin_lock_irqsave(&pctl->lock, flags);
+
+ val = mtk_r32(pctl, i, reg);
+ val &= ~mask;
+ val |= set;
+ mtk_w32(pctl, i, reg, val);
++
++ spin_unlock_irqrestore(&pctl->lock, flags);
+ }
+
+ static int mtk_hw_pin_field_lookup(struct mtk_pinctrl *hw,