linux-kernel - [PATCH v4] gpio: dwapb: mask/unmask IRQ when disable/enale it

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Date: Tue, 19 Dec 2023 18:16:20 +0800
From: xiongxin <xiongxin@...inos.cn>
To: fancer.lancer@...il.com,
	hoan@...amperecomputing.com,
	linus.walleij@...aro.org,
	brgl@...ev.pl,
	andy@...nel.org
Cc: linux-gpio@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	xiongxin <xiongxin@...inos.cn>,
	stable@...nel.org,
	Riwen Lu <luriwen@...inos.cn>
Subject: [PATCH v4] gpio: dwapb: mask/unmask IRQ when disable/enale it

In the hardware implementation of the i2c hid driver based on dwapb gpio
irq, when the user continues to use the i2c hid device in the suspend
process, the i2c hid interrupt will be masked after the resume process
is finished.

This is because the disable_irq()/enable_irq() of the dwapb gpio driver
does not synchronize the irq mask register state. In normal use of the
i2c hid procedure, the gpio irq irq_mask()/irq_unmask() functions are
called in pairs. In case of an exception, i2c_hid_core_suspend() calls
disable_irq() to disable the gpio irq. With low probability, this causes
irq_unmask() to not be called, which causes the gpio irq to be masked
and not unmasked in enable_irq(), raising an exception.

Add synchronization to the masked register state in the
dwapb_irq_enable()/dwapb_irq_disable() function. mask the gpio irq
before disabling it. After enabling the gpio irq, unmask the irq.

Fixes: 7779b3455697 ("gpio: add a driver for the Synopsys DesignWare APB GPIO block")
Cc: stable@...nel.org
Co-developed-by: Riwen Lu <luriwen@...inos.cn>
Signed-off-by: Riwen Lu <luriwen@...inos.cn>
Signed-off-by: xiongxin <xiongxin@...inos.cn>
Acked-by: Serge Semin <fancer.lancer@...il.com>
Reviewed-by: Andy Shevchenko <andy@...nel.org>

---
v4:
	* Add patch tag information
v3:
	* Modify the submitter's information
v2:
	* Resubmit the patch to fix this exception from the dwapb gpio
	  driver side.
v1:
	* Resolve the exception from the IRQ core layer. (key point not
	  found correctly)
---
 drivers/gpio/gpio-dwapb.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/gpio/gpio-dwapb.c b/drivers/gpio/gpio-dwapb.c
index 4a4f61bf6c58..8c59332429c2 100644
--- a/drivers/gpio/gpio-dwapb.c
+++ b/drivers/gpio/gpio-dwapb.c
@@ -282,13 +282,15 @@ static void dwapb_irq_enable(struct irq_data *d)
 {
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 	struct dwapb_gpio *gpio = to_dwapb_gpio(gc);
+	irq_hw_number_t hwirq = irqd_to_hwirq(d);
 	unsigned long flags;
 	u32 val;
 
 	raw_spin_lock_irqsave(&gc->bgpio_lock, flags);
-	val = dwapb_read(gpio, GPIO_INTEN);
-	val |= BIT(irqd_to_hwirq(d));
+	val = dwapb_read(gpio, GPIO_INTEN) | BIT(hwirq);
 	dwapb_write(gpio, GPIO_INTEN, val);
+	val = dwapb_read(gpio, GPIO_INTMASK) & ~BIT(hwirq);
+	dwapb_write(gpio, GPIO_INTMASK, val);
 	raw_spin_unlock_irqrestore(&gc->bgpio_lock, flags);
 }
 
@@ -296,12 +298,14 @@ static void dwapb_irq_disable(struct irq_data *d)
 {
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 	struct dwapb_gpio *gpio = to_dwapb_gpio(gc);
+	irq_hw_number_t hwirq = irqd_to_hwirq(d);
 	unsigned long flags;
 	u32 val;
 
 	raw_spin_lock_irqsave(&gc->bgpio_lock, flags);
-	val = dwapb_read(gpio, GPIO_INTEN);
-	val &= ~BIT(irqd_to_hwirq(d));
+	val = dwapb_read(gpio, GPIO_INTMASK) | BIT(hwirq);
+	dwapb_write(gpio, GPIO_INTMASK, val);
+	val = dwapb_read(gpio, GPIO_INTEN) & ~BIT(hwirq);
 	dwapb_write(gpio, GPIO_INTEN, val);
 	raw_spin_unlock_irqrestore(&gc->bgpio_lock, flags);
 }
-- 
2.34.1