2019-10-09 08:41:57

by Hui Song

[permalink] [raw]
Subject: [PATCH v6] gpio/mpc8xxx: change irq handler from chained to normal

From: Song Hui <[email protected]>

More than one gpio controllers can share one interrupt, change the
driver to request shared irq.

While this will work, it will mess up userspace accounting of the number
of interrupts per second in tools such as vmstat. The reason is that
for every GPIO interrupt, /proc/interrupts records the count against GIC
interrupt 68 or 69, as well as the GPIO itself. So, for every GPIO
interrupt, the total number of interrupts that the system has seen
increments by two

Signed-off-by: Laurentiu Tudor <[email protected]>
Signed-off-by: Alex Marginean <[email protected]>
Signed-off-by: Song Hui <[email protected]>
---
Changes in v6:
- change request_irq to devm_request_irq and add commit message.
Changes in v5:
- add traverse every bit function.
Changes in v4:
- convert 'pr_err' to 'dev_err'.
Changes in v3:
- update the patch description.
Changes in v2:
- delete the compatible of ls1088a.

drivers/gpio/gpio-mpc8xxx.c | 31 ++++++++++++++++++++-----------
1 file changed, 20 insertions(+), 11 deletions(-)

diff --git a/drivers/gpio/gpio-mpc8xxx.c b/drivers/gpio/gpio-mpc8xxx.c
index 16a47de..f0be284 100644
--- a/drivers/gpio/gpio-mpc8xxx.c
+++ b/drivers/gpio/gpio-mpc8xxx.c
@@ -22,6 +22,7 @@
#include <linux/irq.h>
#include <linux/gpio/driver.h>
#include <linux/bitops.h>
+#include <linux/interrupt.h>

#define MPC8XXX_GPIO_PINS 32

@@ -127,20 +128,20 @@ static int mpc8xxx_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
return -ENXIO;
}

-static void mpc8xxx_gpio_irq_cascade(struct irq_desc *desc)
+static irqreturn_t mpc8xxx_gpio_irq_cascade(int irq, void *data)
{
- struct mpc8xxx_gpio_chip *mpc8xxx_gc = irq_desc_get_handler_data(desc);
- struct irq_chip *chip = irq_desc_get_chip(desc);
+ struct mpc8xxx_gpio_chip *mpc8xxx_gc = data;
struct gpio_chip *gc = &mpc8xxx_gc->gc;
unsigned int mask;
+ int i;

mask = gc->read_reg(mpc8xxx_gc->regs + GPIO_IER)
& gc->read_reg(mpc8xxx_gc->regs + GPIO_IMR);
- if (mask)
+ for_each_set_bit(i, &mask, 32)
generic_handle_irq(irq_linear_revmap(mpc8xxx_gc->irq,
- 32 - ffs(mask)));
- if (chip->irq_eoi)
- chip->irq_eoi(&desc->irq_data);
+ 31 - i));
+
+ return IRQ_HANDLED;
}

static void mpc8xxx_irq_unmask(struct irq_data *d)
@@ -388,8 +389,8 @@ static int mpc8xxx_probe(struct platform_device *pdev)

ret = gpiochip_add_data(gc, mpc8xxx_gc);
if (ret) {
- pr_err("%pOF: GPIO chip registration failed with status %d\n",
- np, ret);
+ dev_err(&pdev->dev, "%pOF: GPIO chip registration failed with status %d\n",
+ np, ret);
goto err;
}

@@ -409,8 +410,16 @@ static int mpc8xxx_probe(struct platform_device *pdev)
if (devtype->gpio_dir_in_init)
devtype->gpio_dir_in_init(gc);

- irq_set_chained_handler_and_data(mpc8xxx_gc->irqn,
- mpc8xxx_gpio_irq_cascade, mpc8xxx_gc);
+ ret = devm_request_irq(&pdev->dev, mpc8xxx_gc->irqn,
+ mpc8xxx_gpio_irq_cascade,
+ IRQF_NO_THREAD | IRQF_SHARED, "gpio-cascade",
+ mpc8xxx_gc);
+ if (ret) {
+ dev_err(&pdev->dev, "%s: failed to devm_request_irq(%d), ret = %d\n",
+ np->full_name, mpc8xxx_gc->irqn, ret);
+ goto err;
+ }
+
return 0;
err:
iounmap(mpc8xxx_gc->regs);
--
2.9.5


2019-10-09 16:35:01

by Bartosz Golaszewski

[permalink] [raw]
Subject: Re: [PATCH v6] gpio/mpc8xxx: change irq handler from chained to normal

śr., 9 paź 2019 o 10:41 Hui Song <[email protected]> napisał(a):
>
> From: Song Hui <[email protected]>
>
> More than one gpio controllers can share one interrupt, change the
> driver to request shared irq.
>
> While this will work, it will mess up userspace accounting of the number
> of interrupts per second in tools such as vmstat. The reason is that
> for every GPIO interrupt, /proc/interrupts records the count against GIC
> interrupt 68 or 69, as well as the GPIO itself. So, for every GPIO
> interrupt, the total number of interrupts that the system has seen
> increments by two
>
> Signed-off-by: Laurentiu Tudor <[email protected]>
> Signed-off-by: Alex Marginean <[email protected]>
> Signed-off-by: Song Hui <[email protected]>
> ---
> Changes in v6:
> - change request_irq to devm_request_irq and add commit message.
> Changes in v5:
> - add traverse every bit function.
> Changes in v4:
> - convert 'pr_err' to 'dev_err'.
> Changes in v3:
> - update the patch description.
> Changes in v2:
> - delete the compatible of ls1088a.
>
> drivers/gpio/gpio-mpc8xxx.c | 31 ++++++++++++++++++++-----------
> 1 file changed, 20 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpio/gpio-mpc8xxx.c b/drivers/gpio/gpio-mpc8xxx.c
> index 16a47de..f0be284 100644
> --- a/drivers/gpio/gpio-mpc8xxx.c
> +++ b/drivers/gpio/gpio-mpc8xxx.c
> @@ -22,6 +22,7 @@
> #include <linux/irq.h>
> #include <linux/gpio/driver.h>
> #include <linux/bitops.h>
> +#include <linux/interrupt.h>
>
> #define MPC8XXX_GPIO_PINS 32
>
> @@ -127,20 +128,20 @@ static int mpc8xxx_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
> return -ENXIO;
> }
>
> -static void mpc8xxx_gpio_irq_cascade(struct irq_desc *desc)
> +static irqreturn_t mpc8xxx_gpio_irq_cascade(int irq, void *data)
> {
> - struct mpc8xxx_gpio_chip *mpc8xxx_gc = irq_desc_get_handler_data(desc);
> - struct irq_chip *chip = irq_desc_get_chip(desc);
> + struct mpc8xxx_gpio_chip *mpc8xxx_gc = data;
> struct gpio_chip *gc = &mpc8xxx_gc->gc;
> unsigned int mask;
> + int i;
>
> mask = gc->read_reg(mpc8xxx_gc->regs + GPIO_IER)
> & gc->read_reg(mpc8xxx_gc->regs + GPIO_IMR);
> - if (mask)
> + for_each_set_bit(i, &mask, 32)
> generic_handle_irq(irq_linear_revmap(mpc8xxx_gc->irq,
> - 32 - ffs(mask)));
> - if (chip->irq_eoi)
> - chip->irq_eoi(&desc->irq_data);
> + 31 - i));
> +
> + return IRQ_HANDLED;
> }
>
> static void mpc8xxx_irq_unmask(struct irq_data *d)
> @@ -388,8 +389,8 @@ static int mpc8xxx_probe(struct platform_device *pdev)
>
> ret = gpiochip_add_data(gc, mpc8xxx_gc);
> if (ret) {
> - pr_err("%pOF: GPIO chip registration failed with status %d\n",
> - np, ret);
> + dev_err(&pdev->dev, "%pOF: GPIO chip registration failed with status %d\n",
> + np, ret);

This is unrelated to the patch. Please put it in a separate patch.

Bart

> goto err;
> }
>
> @@ -409,8 +410,16 @@ static int mpc8xxx_probe(struct platform_device *pdev)
> if (devtype->gpio_dir_in_init)
> devtype->gpio_dir_in_init(gc);
>
> - irq_set_chained_handler_and_data(mpc8xxx_gc->irqn,
> - mpc8xxx_gpio_irq_cascade, mpc8xxx_gc);
> + ret = devm_request_irq(&pdev->dev, mpc8xxx_gc->irqn,
> + mpc8xxx_gpio_irq_cascade,
> + IRQF_NO_THREAD | IRQF_SHARED, "gpio-cascade",
> + mpc8xxx_gc);
> + if (ret) {
> + dev_err(&pdev->dev, "%s: failed to devm_request_irq(%d), ret = %d\n",
> + np->full_name, mpc8xxx_gc->irqn, ret);
> + goto err;
> + }
> +
> return 0;
> err:
> iounmap(mpc8xxx_gc->regs);
> --
> 2.9.5
>

2019-10-09 16:38:09

by Russell King (Oracle)

[permalink] [raw]
Subject: Re: [PATCH v6] gpio/mpc8xxx: change irq handler from chained to normal

On Wed, Oct 09, 2019 at 04:30:21PM +0800, Hui Song wrote:
> From: Song Hui <[email protected]>
>
> More than one gpio controllers can share one interrupt, change the
> driver to request shared irq.
>
> While this will work, it will mess up userspace accounting of the number
> of interrupts per second in tools such as vmstat. The reason is that
> for every GPIO interrupt, /proc/interrupts records the count against GIC
> interrupt 68 or 69, as well as the GPIO itself. So, for every GPIO
> interrupt, the total number of interrupts that the system has seen
> increments by two
>
> Signed-off-by: Laurentiu Tudor <[email protected]>
> Signed-off-by: Alex Marginean <[email protected]>
> Signed-off-by: Song Hui <[email protected]>
> ---
> Changes in v6:
> - change request_irq to devm_request_irq and add commit message.
> Changes in v5:
> - add traverse every bit function.
> Changes in v4:
> - convert 'pr_err' to 'dev_err'.
> Changes in v3:
> - update the patch description.
> Changes in v2:
> - delete the compatible of ls1088a.
>
> drivers/gpio/gpio-mpc8xxx.c | 31 ++++++++++++++++++++-----------
> 1 file changed, 20 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpio/gpio-mpc8xxx.c b/drivers/gpio/gpio-mpc8xxx.c
> index 16a47de..f0be284 100644
> --- a/drivers/gpio/gpio-mpc8xxx.c
> +++ b/drivers/gpio/gpio-mpc8xxx.c
> @@ -22,6 +22,7 @@
> #include <linux/irq.h>
> #include <linux/gpio/driver.h>
> #include <linux/bitops.h>
> +#include <linux/interrupt.h>
>
> #define MPC8XXX_GPIO_PINS 32
>
> @@ -127,20 +128,20 @@ static int mpc8xxx_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
> return -ENXIO;
> }
>
> -static void mpc8xxx_gpio_irq_cascade(struct irq_desc *desc)
> +static irqreturn_t mpc8xxx_gpio_irq_cascade(int irq, void *data)
> {
> - struct mpc8xxx_gpio_chip *mpc8xxx_gc = irq_desc_get_handler_data(desc);
> - struct irq_chip *chip = irq_desc_get_chip(desc);
> + struct mpc8xxx_gpio_chip *mpc8xxx_gc = data;
> struct gpio_chip *gc = &mpc8xxx_gc->gc;
> unsigned int mask;

This needs to be "unsigned long mask;" for for_each_set_bit() not to
complain.

> + int i;
>
> mask = gc->read_reg(mpc8xxx_gc->regs + GPIO_IER)
> & gc->read_reg(mpc8xxx_gc->regs + GPIO_IMR);
> - if (mask)
> + for_each_set_bit(i, &mask, 32)
> generic_handle_irq(irq_linear_revmap(mpc8xxx_gc->irq,
> - 32 - ffs(mask)));
> - if (chip->irq_eoi)
> - chip->irq_eoi(&desc->irq_data);
> + 31 - i));
> +
> + return IRQ_HANDLED;
> }
>
> static void mpc8xxx_irq_unmask(struct irq_data *d)
> @@ -388,8 +389,8 @@ static int mpc8xxx_probe(struct platform_device *pdev)
>
> ret = gpiochip_add_data(gc, mpc8xxx_gc);
> if (ret) {
> - pr_err("%pOF: GPIO chip registration failed with status %d\n",
> - np, ret);
> + dev_err(&pdev->dev, "%pOF: GPIO chip registration failed with status %d\n",
> + np, ret);
> goto err;
> }
>
> @@ -409,8 +410,16 @@ static int mpc8xxx_probe(struct platform_device *pdev)
> if (devtype->gpio_dir_in_init)
> devtype->gpio_dir_in_init(gc);
>
> - irq_set_chained_handler_and_data(mpc8xxx_gc->irqn,
> - mpc8xxx_gpio_irq_cascade, mpc8xxx_gc);
> + ret = devm_request_irq(&pdev->dev, mpc8xxx_gc->irqn,
> + mpc8xxx_gpio_irq_cascade,
> + IRQF_NO_THREAD | IRQF_SHARED, "gpio-cascade",
> + mpc8xxx_gc);
> + if (ret) {
> + dev_err(&pdev->dev, "%s: failed to devm_request_irq(%d), ret = %d\n",
> + np->full_name, mpc8xxx_gc->irqn, ret);
> + goto err;
> + }
> +
> return 0;
> err:
> iounmap(mpc8xxx_gc->regs);
> --
> 2.9.5
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> [email protected]
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>

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