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gpio: mlxbf3: Support shutdown() function

PATCH Superseded Asmaa Mnebhi 2 participants 2 messages Jun 11, 2024 GPIO

v1 of 2 Superseded Latest is v2 →

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Asmaa Mnebhi

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#0 lore raw

PATCH 1/1 gpio: mlxbf3: Support shutdown() function

During Linux graceful reboot, the GPIO interrupts are not disabled. Since the drivers are not removed during graceful reboot, the logic to call mlxbf3_gpio_irq_disable() is not triggered. Interrupts that remain enabled can cause issues on subsequent boots.

For example, the mlxbf-gige driver contains PHY logic to bring up the link. If the gpio-mlxbf3 driver loads first, the mlxbf-gige driver
will use a GPIO interrupt to bring up the link.
Otherwise, it will use polling.
The next time Linux boots and loads the drivers in this order, we encounter the issue:
- mlxbf-gige loads first. The gige driver uses polling while the GPIO10 interrupt is still enabled from previous boot so if the interrupt triggers, there is nothing to clear it.
- gpio-mlxbf3 loads.
- i2c-mlxbf loads. The interrupt doesn't trigger for I2C because it is shared with the gpio interrupt line which was not cleared.

The solution is to add a shutdown function to the gpio driver to clear and disable all interrupts. Also clear the interrupt after disabling it in mlxbf3_gpio_irq_disable().

Fixes 38a700efc510 ("gpio: mlxbf3: Add gpio driver support")
Signed-off-by Asmaa Mnebhi <[email protected]>
Reviewed-by David Thompson <[email protected]>
---
 drivers/gpio/gpio-mlxbf3.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
drivers/gpio/gpio-mlxbf3.c +14 -0
index d5906d419b0a..40bd93e3d695 100644
@@ -39,6 +39,8 @@
 #define MLXBF_GPIO_CAUSE_OR_EVTEN0        0x14
 #define MLXBF_GPIO_CAUSE_OR_CLRCAUSE      0x18
 
+#define MLXBF_GPIO_CLR_ALL_INTS           0xFFFFFFFF
+
 struct mlxbf3_gpio_context {
 	struct gpio_chip gc;
 

@@ -82,6 +84,8 @@ static void mlxbf3_gpio_irq_disable(struct irq_data *irqd)
 	val = readl(gs->gpio_cause_io + MLXBF_GPIO_CAUSE_OR_EVTEN0);
 	val &= ~BIT(offset);
 	writel(val, gs->gpio_cause_io + MLXBF_GPIO_CAUSE_OR_EVTEN0);
+
+	writel(BIT(offset), gs->gpio_cause_io + MLXBF_GPIO_CAUSE_OR_CLRCAUSE);
 	raw_spin_unlock_irqrestore(&gs->gc.bgpio_lock, flags);
 
 	gpiochip_disable_irq(gc, offset);

@@ -253,6 +257,15 @@ static int mlxbf3_gpio_probe(struct platform_device *pdev)
 	return 0;
 }
 
+static void mlxbf3_gpio_shutdown(struct platform_device *pdev)
+{
+	struct mlxbf3_gpio_context *gs = dev_get_drvdata(&pdev->dev);
+
+	/* Disable and clear all interrupts */
+	writel(0, gs->gpio_cause_io + MLXBF_GPIO_CAUSE_OR_EVTEN0);
+	writel(MLXBF_GPIO_CLR_ALL_INTS, gs->gpio_cause_io + MLXBF_GPIO_CAUSE_OR_CLRCAUSE);
+}
+
 static const struct acpi_device_id mlxbf3_gpio_acpi_match[] = {
 	{ "MLNXBF33", 0 },
 	{}

@@ -265,6 +278,7 @@ static struct platform_driver mlxbf3_gpio_driver = {
 		.acpi_match_table = mlxbf3_gpio_acpi_match,
 	},
 	.probe    = mlxbf3_gpio_probe,
+	.shutdown = mlxbf3_gpio_shutdown,
 };
 module_platform_driver(mlxbf3_gpio_driver);
Signature · 1 line
2.30.1
#1 lore raw
Quoted 6 lines · Asmaa Mnebhi

During Linux graceful reboot, the GPIO interrupts are not disabled. Since the drivers are not removed during graceful reboot, the logic to call mlxbf3_gpio_irq_disable() is not triggered. Interrupts that remain enabled can cause issues on subsequent boots.

Quoted 10 lines

For example, the mlxbf-gige driver contains PHY logic to bring up the link. If the gpio-mlxbf3 driver loads first, the mlxbf-gige driver
will use a GPIO interrupt to bring up the link.
Otherwise, it will use polling.
The next time Linux boots and loads the drivers in this order, we encounter the issue:
- mlxbf-gige loads first. The gige driver uses polling while the GPIO10 interrupt is still enabled from previous boot so if the interrupt triggers, there is nothing to clear it.
- gpio-mlxbf3 loads.
- i2c-mlxbf loads. The interrupt doesn't trigger for I2C because it is shared with the gpio

GPIO

Quoted 3 lines

interrupt line which was not cleared.

The solution is to add a shutdown function to the gpio driver to clear and disable

GPIO

Quoted 1 line

all interrupts. Also clear the interrupt after disabling it in mlxbf3_gpio_irq_disable().

...

Quoted 1 line

+#define MLXBF_GPIO_CLR_ALL_INTS 0xFFFFFFFF

GENMASK()

...

drivers/gpio/gpio-mlxbf3.c static int mlxbf3_gpio_probe(struct platform_device *pdev) · line 262

Quoted 3 lines
drivers/gpio/gpio-mlxbf3.c +3 -0
+static void mlxbf3_gpio_shutdown(struct platform_device *pdev)
+{
+       struct mlxbf3_gpio_context *gs = dev_get_drvdata(&pdev->dev);

platform_get_drvdata()

Quoted 4 lines
drivers/gpio/gpio-mlxbf3.c +4 -0
+       /* Disable and clear all interrupts */
+       writel(0, gs->gpio_cause_io + MLXBF_GPIO_CAUSE_OR_EVTEN0);
+       writel(MLXBF_GPIO_CLR_ALL_INTS, gs->gpio_cause_io + MLXBF_GPIO_CAUSE_OR_CLRCAUSE);
+}
Signature · 2 lines
With Best Regards,
Andy Shevchenko