This is a note to let you know that I've just added the patch titled
pinctrl: baytrail: Serialize all register access
to the 4.2-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
pinctrl-baytrail-serialize-all-register-access.patch
and it can be found in the queue-4.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 39ce8150a079e3ae6ed9abf26d7918a558ef7c19 Mon Sep 17 00:00:00 2001
From: Mika Westerberg <[email protected]>
Date: Tue, 4 Aug 2015 15:03:14 +0300
Subject: pinctrl: baytrail: Serialize all register access
From: Mika Westerberg <[email protected]>
commit 39ce8150a079e3ae6ed9abf26d7918a558ef7c19 upstream.
There is a hardware issue in Intel Baytrail where concurrent GPIO register
access might result reads of 0xffffffff and writes might get dropped
completely.
Prevent this from happening by taking the serializing lock in all places
where it is possible that more than one thread might be accessing the
hardware concurrently.
Signed-off-by: Mika Westerberg <[email protected]>
Signed-off-by: Linus Walleij <[email protected]>
Cc: Lucas De Marchi <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/pinctrl/intel/pinctrl-baytrail.c | 21 ++++++++++++++++-----
1 file changed, 16 insertions(+), 5 deletions(-)
--- a/drivers/pinctrl/intel/pinctrl-baytrail.c
+++ b/drivers/pinctrl/intel/pinctrl-baytrail.c
@@ -201,6 +201,9 @@ static int byt_gpio_request(struct gpio_
struct byt_gpio *vg = to_byt_gpio(chip);
void __iomem *reg = byt_gpio_reg(chip, offset, BYT_CONF0_REG);
u32 value, gpio_mux;
+ unsigned long flags;
+
+ spin_lock_irqsave(&vg->lock, flags);
/*
* In most cases, func pin mux 000 means GPIO function.
@@ -214,18 +217,16 @@ static int byt_gpio_request(struct gpio_
value = readl(reg) & BYT_PIN_MUX;
gpio_mux = byt_get_gpio_mux(vg, offset);
if (WARN_ON(gpio_mux != value)) {
- unsigned long flags;
-
- spin_lock_irqsave(&vg->lock, flags);
value = readl(reg) & ~BYT_PIN_MUX;
value |= gpio_mux;
writel(value, reg);
- spin_unlock_irqrestore(&vg->lock, flags);
dev_warn(&vg->pdev->dev,
"pin %u forcibly re-configured as GPIO\n", offset);
}
+ spin_unlock_irqrestore(&vg->lock, flags);
+
pm_runtime_get(&vg->pdev->dev);
return 0;
@@ -277,7 +278,15 @@ static int byt_irq_type(struct irq_data
static int byt_gpio_get(struct gpio_chip *chip, unsigned offset)
{
void __iomem *reg = byt_gpio_reg(chip, offset, BYT_VAL_REG);
- return readl(reg) & BYT_LEVEL;
+ struct byt_gpio *vg = to_byt_gpio(chip);
+ unsigned long flags;
+ u32 val;
+
+ spin_lock_irqsave(&vg->lock, flags);
+ val = readl(reg);
+ spin_unlock_irqrestore(&vg->lock, flags);
+
+ return val & BYT_LEVEL;
}
static void byt_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
@@ -450,8 +459,10 @@ static void byt_irq_ack(struct irq_data
unsigned offset = irqd_to_hwirq(d);
void __iomem *reg;
+ spin_lock(&vg->lock);
reg = byt_gpio_reg(&vg->chip, offset, BYT_INT_STAT_REG);
writel(BIT(offset % 32), reg);
+ spin_unlock(&vg->lock);
}
static void byt_irq_unmask(struct irq_data *d)
Patches currently in stable-queue which might be from
[email protected] are
queue-4.2/pinctrl-baytrail-use-raw_spinlock-for-locking.patch
queue-4.2/pinctrl-baytrail-serialize-all-register-access.patch
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