[PATCH v2 00/10] gpiolib: Handle immutable irq_chip structures

[PATCH v2 00/10] gpiolib: Handle immutable irq_chip structures

[Marc Zyngier]

This is a followup from [1].

I recently realised that the gpiolib play ugly tricks on the
unsuspecting irq_chip structures by patching the callbacks.

Not only this breaks when an irq_chip structure is made const (which
really should be the default case), but it also forces this structure
to be copied at nauseam for each instance of the GPIO block, which is
a waste of memory.

My current approach is to add a new irq_chip flag (IRQCHIP_IMMUTABLE)
which does what it says on the tin: don't you dare writing to them.
Gpiolib is further updated not to install its own callbacks, and it
becomes the responsibility of the driver to call into the gpiolib when
required. This is similar to what we do for other subsystems such as
PCI-MSI.

5 drivers are updated to this new model: M1, QC, Tegra, pl061 and AMD
(as I actively use them) keeping a single irq_chip structure, marking
it const, and exposing the new flag.

Nothing breaks, the volume of change is small, the memory usage goes
down and we have fewer callbacks that can be used as attack vectors.
What's not to love?

* From v1 [1]:
  - pl061 and AMD drivers converted
  - New helpers to keep the changes small
  - New warning for non-converted drivers
  - Documentation and TODO updates

[1] https://lore.kernel.org/r/20220223154405.54912-1-maz@kernel.org

Marc Zyngier (10):
  gpio: Don't fiddle with irqchips marked as immutable
  gpio: Expose the gpiochip_irq_re[ql]res helpers
  gpio: Add helpers to ease the transition towards immutable irq_chip
  gpio: tegra186: Make the irqchip immutable
  gpio: pl061: Make the irqchip immutable
  pinctrl: apple-gpio: Make the irqchip immutable
  pinctrl: msmgpio: Make the irqchip immutable
  pinctrl: amd: Make the irqchip immutable
  gpio: Update TODO to mention immutable irq_chip structures
  Documentation: Update the recommended pattern for GPIO irqchips

 Documentation/driver-api/gpio/driver.rst | 175 ++++++++++++++++++-----
 drivers/gpio/TODO                        |  19 +++
 drivers/gpio/gpio-pl061.c                |  32 +++--
 drivers/gpio/gpio-tegra186.c             |  32 +++--
 drivers/gpio/gpiolib.c                   |  13 +-
 drivers/pinctrl/pinctrl-amd.c            |  11 +-
 drivers/pinctrl/pinctrl-apple-gpio.c     |  29 ++--
 drivers/pinctrl/qcom/pinctrl-msm.c       |  53 ++++---
 include/linux/gpio/driver.h              |  16 +++
 include/linux/irq.h                      |   2 +
 kernel/irq/debugfs.c                     |   1 +
 11 files changed, 293 insertions(+), 90 deletions(-)

-- 
2.34.1


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[PATCH v2 00/10] gpiolib: Handle immutable irq_chip structures

[Marc Zyngier]

This is a followup from [1].

I recently realised that the gpiolib play ugly tricks on the
unsuspecting irq_chip structures by patching the callbacks.

Not only this breaks when an irq_chip structure is made const (which
really should be the default case), but it also forces this structure
to be copied at nauseam for each instance of the GPIO block, which is
a waste of memory.

My current approach is to add a new irq_chip flag (IRQCHIP_IMMUTABLE)
which does what it says on the tin: don't you dare writing to them.
Gpiolib is further updated not to install its own callbacks, and it
becomes the responsibility of the driver to call into the gpiolib when
required. This is similar to what we do for other subsystems such as
PCI-MSI.

5 drivers are updated to this new model: M1, QC, Tegra, pl061 and AMD
(as I actively use them) keeping a single irq_chip structure, marking
it const, and exposing the new flag.

Nothing breaks, the volume of change is small, the memory usage goes
down and we have fewer callbacks that can be used as attack vectors.
What's not to love?

* From v1 [1]:
  - pl061 and AMD drivers converted
  - New helpers to keep the changes small
  - New warning for non-converted drivers
  - Documentation and TODO updates

[1] https://lore.kernel.org/r/20220223154405.54912-1-maz@kernel.org

Marc Zyngier (10):
  gpio: Don't fiddle with irqchips marked as immutable
  gpio: Expose the gpiochip_irq_re[ql]res helpers
  gpio: Add helpers to ease the transition towards immutable irq_chip
  gpio: tegra186: Make the irqchip immutable
  gpio: pl061: Make the irqchip immutable
  pinctrl: apple-gpio: Make the irqchip immutable
  pinctrl: msmgpio: Make the irqchip immutable
  pinctrl: amd: Make the irqchip immutable
  gpio: Update TODO to mention immutable irq_chip structures
  Documentation: Update the recommended pattern for GPIO irqchips

 Documentation/driver-api/gpio/driver.rst | 175 ++++++++++++++++++-----
 drivers/gpio/TODO                        |  19 +++
 drivers/gpio/gpio-pl061.c                |  32 +++--
 drivers/gpio/gpio-tegra186.c             |  32 +++--
 drivers/gpio/gpiolib.c                   |  13 +-
 drivers/pinctrl/pinctrl-amd.c            |  11 +-
 drivers/pinctrl/pinctrl-apple-gpio.c     |  29 ++--
 drivers/pinctrl/qcom/pinctrl-msm.c       |  53 ++++---
 include/linux/gpio/driver.h              |  16 +++
 include/linux/irq.h                      |   2 +
 kernel/irq/debugfs.c                     |   1 +
 11 files changed, 293 insertions(+), 90 deletions(-)

-- 
2.34.1

[PATCH v2 01/10] gpio: Don't fiddle with irqchips marked as immutable

[Marc Zyngier]

In order to move away from gpiolib messing with the internals of
unsuspecting irqchips, add a flag by which irqchips advertise
that they are not to be messed with, and do solemnly swear that
they correctly call into the gpiolib helpers when required.

Also nudge the users into converting their drivers to the
new model.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 drivers/gpio/gpiolib.c | 7 ++++++-
 include/linux/irq.h    | 2 ++
 kernel/irq/debugfs.c   | 1 +
 3 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index e59884cc12a7..48191e62a3cc 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1475,6 +1475,11 @@ static void gpiochip_set_irq_hooks(struct gpio_chip *gc)
 {
 	struct irq_chip *irqchip = gc->irq.chip;
 
+	if (irqchip->flags & IRQCHIP_IMMUTABLE)
+		return;
+
+	chip_warn(gc, "not an immutable chip, please consider fixing it!\n");
+
 	if (!irqchip->irq_request_resources &&
 	    !irqchip->irq_release_resources) {
 		irqchip->irq_request_resources = gpiochip_irq_reqres;
@@ -1633,7 +1638,7 @@ static void gpiochip_irqchip_remove(struct gpio_chip *gc)
 		irq_domain_remove(gc->irq.domain);
 	}
 
-	if (irqchip) {
+	if (irqchip && !(irqchip->flags & IRQCHIP_IMMUTABLE)) {
 		if (irqchip->irq_request_resources == gpiochip_irq_reqres) {
 			irqchip->irq_request_resources = NULL;
 			irqchip->irq_release_resources = NULL;
diff --git a/include/linux/irq.h b/include/linux/irq.h
index f92788ccdba2..505308253d23 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -569,6 +569,7 @@ struct irq_chip {
  * IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND:  Invokes __enable_irq()/__disable_irq() for wake irqs
  *                                    in the suspend path if they are in disabled state
  * IRQCHIP_AFFINITY_PRE_STARTUP:      Default affinity update before startup
+ * IRQCHIP_IMMUTABLE:		      Don't ever change anything in this chip
  */
 enum {
 	IRQCHIP_SET_TYPE_MASKED			= (1 <<  0),
@@ -582,6 +583,7 @@ enum {
 	IRQCHIP_SUPPORTS_NMI			= (1 <<  8),
 	IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND	= (1 <<  9),
 	IRQCHIP_AFFINITY_PRE_STARTUP		= (1 << 10),
+	IRQCHIP_IMMUTABLE			= (1 << 11),
 };
 
 #include <linux/irqdesc.h>
diff --git a/kernel/irq/debugfs.c b/kernel/irq/debugfs.c
index 2b43f5f5033d..bc8e40cf2b65 100644
--- a/kernel/irq/debugfs.c
+++ b/kernel/irq/debugfs.c
@@ -58,6 +58,7 @@ static const struct irq_bit_descr irqchip_flags[] = {
 	BIT_MASK_DESCR(IRQCHIP_SUPPORTS_LEVEL_MSI),
 	BIT_MASK_DESCR(IRQCHIP_SUPPORTS_NMI),
 	BIT_MASK_DESCR(IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND),
+	BIT_MASK_DESCR(IRQCHIP_IMMUTABLE),
 };
 
 static void
-- 
2.34.1


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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH v2 01/10] gpio: Don't fiddle with irqchips marked as immutable

[Marc Zyngier]

In order to move away from gpiolib messing with the internals of
unsuspecting irqchips, add a flag by which irqchips advertise
that they are not to be messed with, and do solemnly swear that
they correctly call into the gpiolib helpers when required.

Also nudge the users into converting their drivers to the
new model.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 drivers/gpio/gpiolib.c | 7 ++++++-
 include/linux/irq.h    | 2 ++
 kernel/irq/debugfs.c   | 1 +
 3 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index e59884cc12a7..48191e62a3cc 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1475,6 +1475,11 @@ static void gpiochip_set_irq_hooks(struct gpio_chip *gc)
 {
 	struct irq_chip *irqchip = gc->irq.chip;
 
+	if (irqchip->flags & IRQCHIP_IMMUTABLE)
+		return;
+
+	chip_warn(gc, "not an immutable chip, please consider fixing it!\n");
+
 	if (!irqchip->irq_request_resources &&
 	    !irqchip->irq_release_resources) {
 		irqchip->irq_request_resources = gpiochip_irq_reqres;
@@ -1633,7 +1638,7 @@ static void gpiochip_irqchip_remove(struct gpio_chip *gc)
 		irq_domain_remove(gc->irq.domain);
 	}
 
-	if (irqchip) {
+	if (irqchip && !(irqchip->flags & IRQCHIP_IMMUTABLE)) {
 		if (irqchip->irq_request_resources == gpiochip_irq_reqres) {
 			irqchip->irq_request_resources = NULL;
 			irqchip->irq_release_resources = NULL;
diff --git a/include/linux/irq.h b/include/linux/irq.h
index f92788ccdba2..505308253d23 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -569,6 +569,7 @@ struct irq_chip {
  * IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND:  Invokes __enable_irq()/__disable_irq() for wake irqs
  *                                    in the suspend path if they are in disabled state
  * IRQCHIP_AFFINITY_PRE_STARTUP:      Default affinity update before startup
+ * IRQCHIP_IMMUTABLE:		      Don't ever change anything in this chip
  */
 enum {
 	IRQCHIP_SET_TYPE_MASKED			= (1 <<  0),
@@ -582,6 +583,7 @@ enum {
 	IRQCHIP_SUPPORTS_NMI			= (1 <<  8),
 	IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND	= (1 <<  9),
 	IRQCHIP_AFFINITY_PRE_STARTUP		= (1 << 10),
+	IRQCHIP_IMMUTABLE			= (1 << 11),
 };
 
 #include <linux/irqdesc.h>
diff --git a/kernel/irq/debugfs.c b/kernel/irq/debugfs.c
index 2b43f5f5033d..bc8e40cf2b65 100644
--- a/kernel/irq/debugfs.c
+++ b/kernel/irq/debugfs.c
@@ -58,6 +58,7 @@ static const struct irq_bit_descr irqchip_flags[] = {
 	BIT_MASK_DESCR(IRQCHIP_SUPPORTS_LEVEL_MSI),
 	BIT_MASK_DESCR(IRQCHIP_SUPPORTS_NMI),
 	BIT_MASK_DESCR(IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND),
+	BIT_MASK_DESCR(IRQCHIP_IMMUTABLE),
 };
 
 static void
-- 
2.34.1

[PATCH v2 02/10] gpio: Expose the gpiochip_irq_re[ql]res helpers

[Marc Zyngier]

The GPIO subsystem has a couple of internal helpers to manage
resources on behalf of the irqchip. Expose them so that GPIO
drivers can use them directly.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 drivers/gpio/gpiolib.c      | 6 ++++--
 include/linux/gpio/driver.h | 4 ++++
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 48191e62a3cc..36e436a66e09 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1423,19 +1423,21 @@ static int gpiochip_to_irq(struct gpio_chip *gc, unsigned int offset)
 	return irq_create_mapping(domain, offset);
 }
 
-static int gpiochip_irq_reqres(struct irq_data *d)
+int gpiochip_irq_reqres(struct irq_data *d)
 {
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 
 	return gpiochip_reqres_irq(gc, d->hwirq);
 }
+EXPORT_SYMBOL(gpiochip_irq_reqres);
 
-static void gpiochip_irq_relres(struct irq_data *d)
+void gpiochip_irq_relres(struct irq_data *d)
 {
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 
 	gpiochip_relres_irq(gc, d->hwirq);
 }
+EXPORT_SYMBOL(gpiochip_irq_relres);
 
 static void gpiochip_irq_mask(struct irq_data *d)
 {
diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
index 98c93510640e..066bcfdf878d 100644
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -579,6 +579,10 @@ void gpiochip_relres_irq(struct gpio_chip *gc, unsigned int offset);
 void gpiochip_disable_irq(struct gpio_chip *gc, unsigned int offset);
 void gpiochip_enable_irq(struct gpio_chip *gc, unsigned int offset);
 
+/* irq_data versions of the above */
+int gpiochip_irq_reqres(struct irq_data *data);
+void gpiochip_irq_relres(struct irq_data *data);
+
 /* Line status inquiry for drivers */
 bool gpiochip_line_is_open_drain(struct gpio_chip *gc, unsigned int offset);
 bool gpiochip_line_is_open_source(struct gpio_chip *gc, unsigned int offset);
-- 
2.34.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH v2 02/10] gpio: Expose the gpiochip_irq_re[ql]res helpers

[Marc Zyngier]

The GPIO subsystem has a couple of internal helpers to manage
resources on behalf of the irqchip. Expose them so that GPIO
drivers can use them directly.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 drivers/gpio/gpiolib.c      | 6 ++++--
 include/linux/gpio/driver.h | 4 ++++
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 48191e62a3cc..36e436a66e09 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1423,19 +1423,21 @@ static int gpiochip_to_irq(struct gpio_chip *gc, unsigned int offset)
 	return irq_create_mapping(domain, offset);
 }
 
-static int gpiochip_irq_reqres(struct irq_data *d)
+int gpiochip_irq_reqres(struct irq_data *d)
 {
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 
 	return gpiochip_reqres_irq(gc, d->hwirq);
 }
+EXPORT_SYMBOL(gpiochip_irq_reqres);
 
-static void gpiochip_irq_relres(struct irq_data *d)
+void gpiochip_irq_relres(struct irq_data *d)
 {
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 
 	gpiochip_relres_irq(gc, d->hwirq);
 }
+EXPORT_SYMBOL(gpiochip_irq_relres);
 
 static void gpiochip_irq_mask(struct irq_data *d)
 {
diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
index 98c93510640e..066bcfdf878d 100644
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -579,6 +579,10 @@ void gpiochip_relres_irq(struct gpio_chip *gc, unsigned int offset);
 void gpiochip_disable_irq(struct gpio_chip *gc, unsigned int offset);
 void gpiochip_enable_irq(struct gpio_chip *gc, unsigned int offset);
 
+/* irq_data versions of the above */
+int gpiochip_irq_reqres(struct irq_data *data);
+void gpiochip_irq_relres(struct irq_data *data);
+
 /* Line status inquiry for drivers */
 bool gpiochip_line_is_open_drain(struct gpio_chip *gc, unsigned int offset);
 bool gpiochip_line_is_open_source(struct gpio_chip *gc, unsigned int offset);
-- 
2.34.1

[PATCH v2 03/10] gpio: Add helpers to ease the transition towards immutable irq_chip

[Marc Zyngier]

Add a couple of new helpers to make it slightly simpler to convert
drivers to immutable irq_chip structures:

- GPIOCHIP_IRQ_RESOURCE_HELPERS populates the irq_chip structure
  with the resource management callbacks

- gpio_irq_chip_set_chip() populates the gpio_irq_chip.chip
  structure, avoiding the proliferation of ugly casts

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 include/linux/gpio/driver.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
index 066bcfdf878d..832990099097 100644
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -583,6 +583,18 @@ void gpiochip_enable_irq(struct gpio_chip *gc, unsigned int offset);
 int gpiochip_irq_reqres(struct irq_data *data);
 void gpiochip_irq_relres(struct irq_data *data);
 
+/* Paste this in your irq_chip structure  */
+#define	GPIOCHIP_IRQ_RESOURCE_HELPERS					\
+		.irq_request_resources  = gpiochip_irq_reqres,		\
+		.irq_release_resources  = gpiochip_irq_relres
+
+static inline void gpio_irq_chip_set_chip(struct gpio_irq_chip *girq,
+					  const struct irq_chip *chip)
+{
+	/* Yes, dropping const is ugly, but it isn't like we have a choice */
+	girq->chip = (struct irq_chip *)chip;
+}
+
 /* Line status inquiry for drivers */
 bool gpiochip_line_is_open_drain(struct gpio_chip *gc, unsigned int offset);
 bool gpiochip_line_is_open_source(struct gpio_chip *gc, unsigned int offset);
-- 
2.34.1


_______________________________________________
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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH v2 03/10] gpio: Add helpers to ease the transition towards immutable irq_chip

[Marc Zyngier]

Add a couple of new helpers to make it slightly simpler to convert
drivers to immutable irq_chip structures:

- GPIOCHIP_IRQ_RESOURCE_HELPERS populates the irq_chip structure
  with the resource management callbacks

- gpio_irq_chip_set_chip() populates the gpio_irq_chip.chip
  structure, avoiding the proliferation of ugly casts

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 include/linux/gpio/driver.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
index 066bcfdf878d..832990099097 100644
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -583,6 +583,18 @@ void gpiochip_enable_irq(struct gpio_chip *gc, unsigned int offset);
 int gpiochip_irq_reqres(struct irq_data *data);
 void gpiochip_irq_relres(struct irq_data *data);
 
+/* Paste this in your irq_chip structure  */
+#define	GPIOCHIP_IRQ_RESOURCE_HELPERS					\
+		.irq_request_resources  = gpiochip_irq_reqres,		\
+		.irq_release_resources  = gpiochip_irq_relres
+
+static inline void gpio_irq_chip_set_chip(struct gpio_irq_chip *girq,
+					  const struct irq_chip *chip)
+{
+	/* Yes, dropping const is ugly, but it isn't like we have a choice */
+	girq->chip = (struct irq_chip *)chip;
+}
+
 /* Line status inquiry for drivers */
 bool gpiochip_line_is_open_drain(struct gpio_chip *gc, unsigned int offset);
 bool gpiochip_line_is_open_source(struct gpio_chip *gc, unsigned int offset);
-- 
2.34.1

[PATCH v2 04/10] gpio: tegra186: Make the irqchip immutable

[Marc Zyngier]

Prevent gpiolib from messing with the irqchip by advertising
the irq_chip structure as immutable, making it const, and adding
the various calls that gpiolib relies upon.

Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 drivers/gpio/gpio-tegra186.c | 32 +++++++++++++++++++++++---------
 1 file changed, 23 insertions(+), 9 deletions(-)

diff --git a/drivers/gpio/gpio-tegra186.c b/drivers/gpio/gpio-tegra186.c
index 031fe105b58e..84c4f1e9fb0c 100644
--- a/drivers/gpio/gpio-tegra186.c
+++ b/drivers/gpio/gpio-tegra186.c
@@ -80,7 +80,6 @@ struct tegra_gpio_soc {
 
 struct tegra_gpio {
 	struct gpio_chip gpio;
-	struct irq_chip intc;
 	unsigned int num_irq;
 	unsigned int *irq;
 
@@ -372,6 +371,8 @@ static void tegra186_irq_mask(struct irq_data *data)
 	value = readl(base + TEGRA186_GPIO_ENABLE_CONFIG);
 	value &= ~TEGRA186_GPIO_ENABLE_CONFIG_INTERRUPT;
 	writel(value, base + TEGRA186_GPIO_ENABLE_CONFIG);
+
+	gpiochip_disable_irq(&gpio->gpio, data->hwirq);
 }
 
 static void tegra186_irq_unmask(struct irq_data *data)
@@ -385,6 +386,8 @@ static void tegra186_irq_unmask(struct irq_data *data)
 	if (WARN_ON(base == NULL))
 		return;
 
+	gpiochip_enable_irq(&gpio->gpio, data->hwirq);
+
 	value = readl(base + TEGRA186_GPIO_ENABLE_CONFIG);
 	value |= TEGRA186_GPIO_ENABLE_CONFIG_INTERRUPT;
 	writel(value, base + TEGRA186_GPIO_ENABLE_CONFIG);
@@ -456,6 +459,24 @@ static int tegra186_irq_set_wake(struct irq_data *data, unsigned int on)
 	return 0;
 }
 
+static void tegra186_irq_print_chip(struct irq_data *data, struct seq_file *p)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+
+	seq_printf(p, dev_name(gc->parent));
+}
+
+static const struct irq_chip tegra186_gpio_irq_chip = {
+	.irq_ack		= tegra186_irq_ack,
+	.irq_mask		= tegra186_irq_mask,
+	.irq_unmask		= tegra186_irq_unmask,
+	.irq_set_type		= tegra186_irq_set_type,
+	.irq_set_wake		= tegra186_irq_set_wake,
+	.irq_print_chip		= tegra186_irq_print_chip,
+	.flags			= IRQCHIP_IMMUTABLE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
+};
+
 static void tegra186_gpio_irq(struct irq_desc *desc)
 {
 	struct tegra_gpio *gpio = irq_desc_get_handler_data(desc);
@@ -760,15 +781,8 @@ static int tegra186_gpio_probe(struct platform_device *pdev)
 	gpio->gpio.of_xlate = tegra186_gpio_of_xlate;
 #endif /* CONFIG_OF_GPIO */
 
-	gpio->intc.name = dev_name(&pdev->dev);
-	gpio->intc.irq_ack = tegra186_irq_ack;
-	gpio->intc.irq_mask = tegra186_irq_mask;
-	gpio->intc.irq_unmask = tegra186_irq_unmask;
-	gpio->intc.irq_set_type = tegra186_irq_set_type;
-	gpio->intc.irq_set_wake = tegra186_irq_set_wake;
-
 	irq = &gpio->gpio.irq;
-	irq->chip = &gpio->intc;
+	gpio_irq_chip_set_chip(irq, &tegra186_gpio_irq_chip);
 	irq->fwnode = of_node_to_fwnode(pdev->dev.of_node);
 	irq->child_to_parent_hwirq = tegra186_gpio_child_to_parent_hwirq;
 	irq->populate_parent_alloc_arg = tegra186_gpio_populate_parent_fwspec;
-- 
2.34.1


_______________________________________________
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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH v2 04/10] gpio: tegra186: Make the irqchip immutable

[Marc Zyngier]

Prevent gpiolib from messing with the irqchip by advertising
the irq_chip structure as immutable, making it const, and adding
the various calls that gpiolib relies upon.

Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 drivers/gpio/gpio-tegra186.c | 32 +++++++++++++++++++++++---------
 1 file changed, 23 insertions(+), 9 deletions(-)

diff --git a/drivers/gpio/gpio-tegra186.c b/drivers/gpio/gpio-tegra186.c
index 031fe105b58e..84c4f1e9fb0c 100644
--- a/drivers/gpio/gpio-tegra186.c
+++ b/drivers/gpio/gpio-tegra186.c
@@ -80,7 +80,6 @@ struct tegra_gpio_soc {
 
 struct tegra_gpio {
 	struct gpio_chip gpio;
-	struct irq_chip intc;
 	unsigned int num_irq;
 	unsigned int *irq;
 
@@ -372,6 +371,8 @@ static void tegra186_irq_mask(struct irq_data *data)
 	value = readl(base + TEGRA186_GPIO_ENABLE_CONFIG);
 	value &= ~TEGRA186_GPIO_ENABLE_CONFIG_INTERRUPT;
 	writel(value, base + TEGRA186_GPIO_ENABLE_CONFIG);
+
+	gpiochip_disable_irq(&gpio->gpio, data->hwirq);
 }
 
 static void tegra186_irq_unmask(struct irq_data *data)
@@ -385,6 +386,8 @@ static void tegra186_irq_unmask(struct irq_data *data)
 	if (WARN_ON(base == NULL))
 		return;
 
+	gpiochip_enable_irq(&gpio->gpio, data->hwirq);
+
 	value = readl(base + TEGRA186_GPIO_ENABLE_CONFIG);
 	value |= TEGRA186_GPIO_ENABLE_CONFIG_INTERRUPT;
 	writel(value, base + TEGRA186_GPIO_ENABLE_CONFIG);
@@ -456,6 +459,24 @@ static int tegra186_irq_set_wake(struct irq_data *data, unsigned int on)
 	return 0;
 }
 
+static void tegra186_irq_print_chip(struct irq_data *data, struct seq_file *p)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+
+	seq_printf(p, dev_name(gc->parent));
+}
+
+static const struct irq_chip tegra186_gpio_irq_chip = {
+	.irq_ack		= tegra186_irq_ack,
+	.irq_mask		= tegra186_irq_mask,
+	.irq_unmask		= tegra186_irq_unmask,
+	.irq_set_type		= tegra186_irq_set_type,
+	.irq_set_wake		= tegra186_irq_set_wake,
+	.irq_print_chip		= tegra186_irq_print_chip,
+	.flags			= IRQCHIP_IMMUTABLE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
+};
+
 static void tegra186_gpio_irq(struct irq_desc *desc)
 {
 	struct tegra_gpio *gpio = irq_desc_get_handler_data(desc);
@@ -760,15 +781,8 @@ static int tegra186_gpio_probe(struct platform_device *pdev)
 	gpio->gpio.of_xlate = tegra186_gpio_of_xlate;
 #endif /* CONFIG_OF_GPIO */
 
-	gpio->intc.name = dev_name(&pdev->dev);
-	gpio->intc.irq_ack = tegra186_irq_ack;
-	gpio->intc.irq_mask = tegra186_irq_mask;
-	gpio->intc.irq_unmask = tegra186_irq_unmask;
-	gpio->intc.irq_set_type = tegra186_irq_set_type;
-	gpio->intc.irq_set_wake = tegra186_irq_set_wake;
-
 	irq = &gpio->gpio.irq;
-	irq->chip = &gpio->intc;
+	gpio_irq_chip_set_chip(irq, &tegra186_gpio_irq_chip);
 	irq->fwnode = of_node_to_fwnode(pdev->dev.of_node);
 	irq->child_to_parent_hwirq = tegra186_gpio_child_to_parent_hwirq;
 	irq->populate_parent_alloc_arg = tegra186_gpio_populate_parent_fwspec;
-- 
2.34.1

[PATCH v2 05/10] gpio: pl061: Make the irqchip immutable

[Marc Zyngier]

Prevent gpiolib from messing with the irqchip by advertising
the irq_chip structure as immutable, making it const, and adding
the various calls that gpiolib relies upon.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 drivers/gpio/gpio-pl061.c | 32 +++++++++++++++++++++++---------
 1 file changed, 23 insertions(+), 9 deletions(-)

diff --git a/drivers/gpio/gpio-pl061.c b/drivers/gpio/gpio-pl061.c
index 4ecab700f23f..6464056cb6ae 100644
--- a/drivers/gpio/gpio-pl061.c
+++ b/drivers/gpio/gpio-pl061.c
@@ -52,7 +52,6 @@ struct pl061 {
 
 	void __iomem		*base;
 	struct gpio_chip	gc;
-	struct irq_chip		irq_chip;
 	int			parent_irq;
 
 #ifdef CONFIG_PM
@@ -241,6 +240,8 @@ static void pl061_irq_mask(struct irq_data *d)
 	gpioie = readb(pl061->base + GPIOIE) & ~mask;
 	writeb(gpioie, pl061->base + GPIOIE);
 	raw_spin_unlock(&pl061->lock);
+
+	gpiochip_disable_irq(gc, d->hwirq);
 }
 
 static void pl061_irq_unmask(struct irq_data *d)
@@ -250,6 +251,8 @@ static void pl061_irq_unmask(struct irq_data *d)
 	u8 mask = BIT(irqd_to_hwirq(d) % PL061_GPIO_NR);
 	u8 gpioie;
 
+	gpiochip_enable_irq(gc, d->hwirq);
+
 	raw_spin_lock(&pl061->lock);
 	gpioie = readb(pl061->base + GPIOIE) | mask;
 	writeb(gpioie, pl061->base + GPIOIE);
@@ -283,6 +286,24 @@ static int pl061_irq_set_wake(struct irq_data *d, unsigned int state)
 	return irq_set_irq_wake(pl061->parent_irq, state);
 }
 
+static void pl061_irq_print_chip(struct irq_data *data, struct seq_file *p)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+
+	seq_printf(p, dev_name(gc->parent));
+}
+
+static const struct irq_chip pl061_irq_chip = {
+	.irq_ack		= pl061_irq_ack,
+	.irq_mask		= pl061_irq_mask,
+	.irq_unmask		= pl061_irq_unmask,
+	.irq_set_type		= pl061_irq_type,
+	.irq_set_wake		= pl061_irq_set_wake,
+	.irq_print_chip		= pl061_irq_print_chip,
+	.flags			= IRQCHIP_IMMUTABLE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
+};
+
 static int pl061_probe(struct amba_device *adev, const struct amba_id *id)
 {
 	struct device *dev = &adev->dev;
@@ -315,13 +336,6 @@ static int pl061_probe(struct amba_device *adev, const struct amba_id *id)
 	/*
 	 * irq_chip support
 	 */
-	pl061->irq_chip.name = dev_name(dev);
-	pl061->irq_chip.irq_ack	= pl061_irq_ack;
-	pl061->irq_chip.irq_mask = pl061_irq_mask;
-	pl061->irq_chip.irq_unmask = pl061_irq_unmask;
-	pl061->irq_chip.irq_set_type = pl061_irq_type;
-	pl061->irq_chip.irq_set_wake = pl061_irq_set_wake;
-
 	writeb(0, pl061->base + GPIOIE); /* disable irqs */
 	irq = adev->irq[0];
 	if (!irq)
@@ -329,7 +343,7 @@ static int pl061_probe(struct amba_device *adev, const struct amba_id *id)
 	pl061->parent_irq = irq;
 
 	girq = &pl061->gc.irq;
-	girq->chip = &pl061->irq_chip;
+	gpio_irq_chip_set_chip(girq, &pl061_irq_chip);
 	girq->parent_handler = pl061_irq_handler;
 	girq->num_parents = 1;
 	girq->parents = devm_kcalloc(dev, 1, sizeof(*girq->parents),
-- 
2.34.1


_______________________________________________
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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH v2 05/10] gpio: pl061: Make the irqchip immutable

[Marc Zyngier]

Prevent gpiolib from messing with the irqchip by advertising
the irq_chip structure as immutable, making it const, and adding
the various calls that gpiolib relies upon.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 drivers/gpio/gpio-pl061.c | 32 +++++++++++++++++++++++---------
 1 file changed, 23 insertions(+), 9 deletions(-)

diff --git a/drivers/gpio/gpio-pl061.c b/drivers/gpio/gpio-pl061.c
index 4ecab700f23f..6464056cb6ae 100644
--- a/drivers/gpio/gpio-pl061.c
+++ b/drivers/gpio/gpio-pl061.c
@@ -52,7 +52,6 @@ struct pl061 {
 
 	void __iomem		*base;
 	struct gpio_chip	gc;
-	struct irq_chip		irq_chip;
 	int			parent_irq;
 
 #ifdef CONFIG_PM
@@ -241,6 +240,8 @@ static void pl061_irq_mask(struct irq_data *d)
 	gpioie = readb(pl061->base + GPIOIE) & ~mask;
 	writeb(gpioie, pl061->base + GPIOIE);
 	raw_spin_unlock(&pl061->lock);
+
+	gpiochip_disable_irq(gc, d->hwirq);
 }
 
 static void pl061_irq_unmask(struct irq_data *d)
@@ -250,6 +251,8 @@ static void pl061_irq_unmask(struct irq_data *d)
 	u8 mask = BIT(irqd_to_hwirq(d) % PL061_GPIO_NR);
 	u8 gpioie;
 
+	gpiochip_enable_irq(gc, d->hwirq);
+
 	raw_spin_lock(&pl061->lock);
 	gpioie = readb(pl061->base + GPIOIE) | mask;
 	writeb(gpioie, pl061->base + GPIOIE);
@@ -283,6 +286,24 @@ static int pl061_irq_set_wake(struct irq_data *d, unsigned int state)
 	return irq_set_irq_wake(pl061->parent_irq, state);
 }
 
+static void pl061_irq_print_chip(struct irq_data *data, struct seq_file *p)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+
+	seq_printf(p, dev_name(gc->parent));
+}
+
+static const struct irq_chip pl061_irq_chip = {
+	.irq_ack		= pl061_irq_ack,
+	.irq_mask		= pl061_irq_mask,
+	.irq_unmask		= pl061_irq_unmask,
+	.irq_set_type		= pl061_irq_type,
+	.irq_set_wake		= pl061_irq_set_wake,
+	.irq_print_chip		= pl061_irq_print_chip,
+	.flags			= IRQCHIP_IMMUTABLE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
+};
+
 static int pl061_probe(struct amba_device *adev, const struct amba_id *id)
 {
 	struct device *dev = &adev->dev;
@@ -315,13 +336,6 @@ static int pl061_probe(struct amba_device *adev, const struct amba_id *id)
 	/*
 	 * irq_chip support
 	 */
-	pl061->irq_chip.name = dev_name(dev);
-	pl061->irq_chip.irq_ack	= pl061_irq_ack;
-	pl061->irq_chip.irq_mask = pl061_irq_mask;
-	pl061->irq_chip.irq_unmask = pl061_irq_unmask;
-	pl061->irq_chip.irq_set_type = pl061_irq_type;
-	pl061->irq_chip.irq_set_wake = pl061_irq_set_wake;
-
 	writeb(0, pl061->base + GPIOIE); /* disable irqs */
 	irq = adev->irq[0];
 	if (!irq)
@@ -329,7 +343,7 @@ static int pl061_probe(struct amba_device *adev, const struct amba_id *id)
 	pl061->parent_irq = irq;
 
 	girq = &pl061->gc.irq;
-	girq->chip = &pl061->irq_chip;
+	gpio_irq_chip_set_chip(girq, &pl061_irq_chip);
 	girq->parent_handler = pl061_irq_handler;
 	girq->num_parents = 1;
 	girq->parents = devm_kcalloc(dev, 1, sizeof(*girq->parents),
-- 
2.34.1

[PATCH v2 06/10] pinctrl: apple-gpio: Make the irqchip immutable

[Marc Zyngier]

Prevent gpiolib from messing with the irqchip by advertising
the irq_chip structure as immutable, making it const, and adding
the various calls that gpiolib relies upon.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 drivers/pinctrl/pinctrl-apple-gpio.c | 29 +++++++++++++++-------------
 1 file changed, 16 insertions(+), 13 deletions(-)

diff --git a/drivers/pinctrl/pinctrl-apple-gpio.c b/drivers/pinctrl/pinctrl-apple-gpio.c
index 72f4dd2466e1..5e610849dfc3 100644
--- a/drivers/pinctrl/pinctrl-apple-gpio.c
+++ b/drivers/pinctrl/pinctrl-apple-gpio.c
@@ -36,7 +36,6 @@ struct apple_gpio_pinctrl {
 
 	struct pinctrl_desc pinctrl_desc;
 	struct gpio_chip gpio_chip;
-	struct irq_chip irq_chip;
 	u8 irqgrps[];
 };
 
@@ -275,17 +274,21 @@ static unsigned int apple_gpio_irq_type(unsigned int type)
 
 static void apple_gpio_irq_mask(struct irq_data *data)
 {
-	struct apple_gpio_pinctrl *pctl = gpiochip_get_data(irq_data_get_irq_chip_data(data));
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+	struct apple_gpio_pinctrl *pctl = gpiochip_get_data(gc);
 
 	apple_gpio_set_reg(pctl, data->hwirq, REG_GPIOx_MODE,
 	                   FIELD_PREP(REG_GPIOx_MODE, REG_GPIOx_IN_IRQ_OFF));
+	gpiochip_disable_irq(gc, data->hwirq);
 }
 
 static void apple_gpio_irq_unmask(struct irq_data *data)
 {
-	struct apple_gpio_pinctrl *pctl = gpiochip_get_data(irq_data_get_irq_chip_data(data));
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+	struct apple_gpio_pinctrl *pctl = gpiochip_get_data(gc);
 	unsigned int irqtype = apple_gpio_irq_type(irqd_get_trigger_type(data));
 
+	gpiochip_enable_irq(gc, data->hwirq);
 	apple_gpio_set_reg(pctl, data->hwirq, REG_GPIOx_MODE,
 	                   FIELD_PREP(REG_GPIOx_MODE, irqtype));
 }
@@ -343,13 +346,15 @@ static void apple_gpio_irq_handler(struct irq_desc *desc)
 	chained_irq_exit(chip, desc);
 }
 
-static struct irq_chip apple_gpio_irqchip = {
-	.name		= "Apple-GPIO",
-	.irq_startup	= apple_gpio_irq_startup,
-	.irq_ack	= apple_gpio_irq_ack,
-	.irq_mask	= apple_gpio_irq_mask,
-	.irq_unmask	= apple_gpio_irq_unmask,
-	.irq_set_type	= apple_gpio_irq_set_type,
+static const struct irq_chip apple_gpio_irqchip = {
+	.name			= "Apple-GPIO",
+	.irq_startup		= apple_gpio_irq_startup,
+	.irq_ack		= apple_gpio_irq_ack,
+	.irq_mask		= apple_gpio_irq_mask,
+	.irq_unmask		= apple_gpio_irq_unmask,
+	.irq_set_type		= apple_gpio_irq_set_type,
+	.flags			= IRQCHIP_IMMUTABLE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
 };
 
 /* Probe & register */
@@ -360,8 +365,6 @@ static int apple_gpio_register(struct apple_gpio_pinctrl *pctl)
 	void **irq_data = NULL;
 	int ret;
 
-	pctl->irq_chip = apple_gpio_irqchip;
-
 	pctl->gpio_chip.label = dev_name(pctl->dev);
 	pctl->gpio_chip.request = gpiochip_generic_request;
 	pctl->gpio_chip.free = gpiochip_generic_free;
@@ -377,7 +380,7 @@ static int apple_gpio_register(struct apple_gpio_pinctrl *pctl)
 	if (girq->num_parents) {
 		int i;
 
-		girq->chip = &pctl->irq_chip;
+		gpio_irq_chip_set_chip(girq, &apple_gpio_irqchip);
 		girq->parent_handler = apple_gpio_irq_handler;
 
 		girq->parents = kmalloc_array(girq->num_parents,
-- 
2.34.1


_______________________________________________
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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH v2 06/10] pinctrl: apple-gpio: Make the irqchip immutable

[Marc Zyngier]

Prevent gpiolib from messing with the irqchip by advertising
the irq_chip structure as immutable, making it const, and adding
the various calls that gpiolib relies upon.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 drivers/pinctrl/pinctrl-apple-gpio.c | 29 +++++++++++++++-------------
 1 file changed, 16 insertions(+), 13 deletions(-)

diff --git a/drivers/pinctrl/pinctrl-apple-gpio.c b/drivers/pinctrl/pinctrl-apple-gpio.c
index 72f4dd2466e1..5e610849dfc3 100644
--- a/drivers/pinctrl/pinctrl-apple-gpio.c
+++ b/drivers/pinctrl/pinctrl-apple-gpio.c
@@ -36,7 +36,6 @@ struct apple_gpio_pinctrl {
 
 	struct pinctrl_desc pinctrl_desc;
 	struct gpio_chip gpio_chip;
-	struct irq_chip irq_chip;
 	u8 irqgrps[];
 };
 
@@ -275,17 +274,21 @@ static unsigned int apple_gpio_irq_type(unsigned int type)
 
 static void apple_gpio_irq_mask(struct irq_data *data)
 {
-	struct apple_gpio_pinctrl *pctl = gpiochip_get_data(irq_data_get_irq_chip_data(data));
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+	struct apple_gpio_pinctrl *pctl = gpiochip_get_data(gc);
 
 	apple_gpio_set_reg(pctl, data->hwirq, REG_GPIOx_MODE,
 	                   FIELD_PREP(REG_GPIOx_MODE, REG_GPIOx_IN_IRQ_OFF));
+	gpiochip_disable_irq(gc, data->hwirq);
 }
 
 static void apple_gpio_irq_unmask(struct irq_data *data)
 {
-	struct apple_gpio_pinctrl *pctl = gpiochip_get_data(irq_data_get_irq_chip_data(data));
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+	struct apple_gpio_pinctrl *pctl = gpiochip_get_data(gc);
 	unsigned int irqtype = apple_gpio_irq_type(irqd_get_trigger_type(data));
 
+	gpiochip_enable_irq(gc, data->hwirq);
 	apple_gpio_set_reg(pctl, data->hwirq, REG_GPIOx_MODE,
 	                   FIELD_PREP(REG_GPIOx_MODE, irqtype));
 }
@@ -343,13 +346,15 @@ static void apple_gpio_irq_handler(struct irq_desc *desc)
 	chained_irq_exit(chip, desc);
 }
 
-static struct irq_chip apple_gpio_irqchip = {
-	.name		= "Apple-GPIO",
-	.irq_startup	= apple_gpio_irq_startup,
-	.irq_ack	= apple_gpio_irq_ack,
-	.irq_mask	= apple_gpio_irq_mask,
-	.irq_unmask	= apple_gpio_irq_unmask,
-	.irq_set_type	= apple_gpio_irq_set_type,
+static const struct irq_chip apple_gpio_irqchip = {
+	.name			= "Apple-GPIO",
+	.irq_startup		= apple_gpio_irq_startup,
+	.irq_ack		= apple_gpio_irq_ack,
+	.irq_mask		= apple_gpio_irq_mask,
+	.irq_unmask		= apple_gpio_irq_unmask,
+	.irq_set_type		= apple_gpio_irq_set_type,
+	.flags			= IRQCHIP_IMMUTABLE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
 };
 
 /* Probe & register */
@@ -360,8 +365,6 @@ static int apple_gpio_register(struct apple_gpio_pinctrl *pctl)
 	void **irq_data = NULL;
 	int ret;
 
-	pctl->irq_chip = apple_gpio_irqchip;
-
 	pctl->gpio_chip.label = dev_name(pctl->dev);
 	pctl->gpio_chip.request = gpiochip_generic_request;
 	pctl->gpio_chip.free = gpiochip_generic_free;
@@ -377,7 +380,7 @@ static int apple_gpio_register(struct apple_gpio_pinctrl *pctl)
 	if (girq->num_parents) {
 		int i;
 
-		girq->chip = &pctl->irq_chip;
+		gpio_irq_chip_set_chip(girq, &apple_gpio_irqchip);
 		girq->parent_handler = apple_gpio_irq_handler;
 
 		girq->parents = kmalloc_array(girq->num_parents,
-- 
2.34.1

[PATCH v2 07/10] pinctrl: msmgpio: Make the irqchip immutable

[Marc Zyngier]

Prevent gpiolib from messing with the irqchip by advertising
the irq_chip structure as immutable, making it const, and adding
the various calls that gpiolib relies upon.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 drivers/pinctrl/qcom/pinctrl-msm.c | 53 +++++++++++++++++++-----------
 1 file changed, 33 insertions(+), 20 deletions(-)

diff --git a/drivers/pinctrl/qcom/pinctrl-msm.c b/drivers/pinctrl/qcom/pinctrl-msm.c
index 966ea6622ff3..a2abfe987ab1 100644
--- a/drivers/pinctrl/qcom/pinctrl-msm.c
+++ b/drivers/pinctrl/qcom/pinctrl-msm.c
@@ -42,7 +42,6 @@
  * @chip:           gpiochip handle.
  * @desc:           pin controller descriptor
  * @restart_nb:     restart notifier block.
- * @irq_chip:       irq chip information
  * @irq:            parent irq for the TLMM irq_chip.
  * @intr_target_use_scm: route irq to application cpu using scm calls
  * @lock:           Spinlock to protect register resources as well
@@ -63,7 +62,6 @@ struct msm_pinctrl {
 	struct pinctrl_desc desc;
 	struct notifier_block restart_nb;
 
-	struct irq_chip irq_chip;
 	int irq;
 
 	bool intr_target_use_scm;
@@ -868,6 +866,8 @@ static void msm_gpio_irq_enable(struct irq_data *d)
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 	struct msm_pinctrl *pctrl = gpiochip_get_data(gc);
 
+	gpiochip_enable_irq(gc, d->hwirq);
+
 	if (d->parent_data)
 		irq_chip_enable_parent(d);
 
@@ -885,6 +885,8 @@ static void msm_gpio_irq_disable(struct irq_data *d)
 
 	if (!test_bit(d->hwirq, pctrl->skip_wake_irqs))
 		msm_gpio_irq_mask(d);
+
+	gpiochip_disable_irq(gc, d->hwirq);
 }
 
 /**
@@ -958,6 +960,14 @@ static void msm_gpio_irq_ack(struct irq_data *d)
 	raw_spin_unlock_irqrestore(&pctrl->lock, flags);
 }
 
+static void msm_gpio_irq_eoi(struct irq_data *d)
+{
+	d = d->parent_data;
+
+	if (d)
+		d->chip->irq_eoi(d);
+}
+
 static bool msm_gpio_needs_dual_edge_parent_workaround(struct irq_data *d,
 						       unsigned int type)
 {
@@ -1255,6 +1265,26 @@ static bool msm_gpio_needs_valid_mask(struct msm_pinctrl *pctrl)
 	return device_property_count_u16(pctrl->dev, "gpios") > 0;
 }
 
+static const struct irq_chip msm_gpio_irq_chip = {
+	.name			= "msmgpio",
+	.irq_enable		= msm_gpio_irq_enable,
+	.irq_disable		= msm_gpio_irq_disable,
+	.irq_mask		= msm_gpio_irq_mask,
+	.irq_unmask		= msm_gpio_irq_unmask,
+	.irq_ack		= msm_gpio_irq_ack,
+	.irq_eoi		= msm_gpio_irq_eoi,
+	.irq_set_type		= msm_gpio_irq_set_type,
+	.irq_set_wake		= msm_gpio_irq_set_wake,
+	.irq_request_resources	= msm_gpio_irq_reqres,
+	.irq_release_resources	= msm_gpio_irq_relres,
+	.irq_set_affinity	= msm_gpio_irq_set_affinity,
+	.irq_set_vcpu_affinity	= msm_gpio_irq_set_vcpu_affinity,
+	.flags			= (IRQCHIP_MASK_ON_SUSPEND |
+				   IRQCHIP_SET_TYPE_MASKED |
+				   IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND |
+				   IRQCHIP_IMMUTABLE),
+};
+
 static int msm_gpio_init(struct msm_pinctrl *pctrl)
 {
 	struct gpio_chip *chip;
@@ -1276,22 +1306,6 @@ static int msm_gpio_init(struct msm_pinctrl *pctrl)
 	if (msm_gpio_needs_valid_mask(pctrl))
 		chip->init_valid_mask = msm_gpio_init_valid_mask;
 
-	pctrl->irq_chip.name = "msmgpio";
-	pctrl->irq_chip.irq_enable = msm_gpio_irq_enable;
-	pctrl->irq_chip.irq_disable = msm_gpio_irq_disable;
-	pctrl->irq_chip.irq_mask = msm_gpio_irq_mask;
-	pctrl->irq_chip.irq_unmask = msm_gpio_irq_unmask;
-	pctrl->irq_chip.irq_ack = msm_gpio_irq_ack;
-	pctrl->irq_chip.irq_set_type = msm_gpio_irq_set_type;
-	pctrl->irq_chip.irq_set_wake = msm_gpio_irq_set_wake;
-	pctrl->irq_chip.irq_request_resources = msm_gpio_irq_reqres;
-	pctrl->irq_chip.irq_release_resources = msm_gpio_irq_relres;
-	pctrl->irq_chip.irq_set_affinity = msm_gpio_irq_set_affinity;
-	pctrl->irq_chip.irq_set_vcpu_affinity = msm_gpio_irq_set_vcpu_affinity;
-	pctrl->irq_chip.flags = IRQCHIP_MASK_ON_SUSPEND |
-				IRQCHIP_SET_TYPE_MASKED |
-				IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND;
-
 	np = of_parse_phandle(pctrl->dev->of_node, "wakeup-parent", 0);
 	if (np) {
 		chip->irq.parent_domain = irq_find_matching_host(np,
@@ -1300,7 +1314,6 @@ static int msm_gpio_init(struct msm_pinctrl *pctrl)
 		if (!chip->irq.parent_domain)
 			return -EPROBE_DEFER;
 		chip->irq.child_to_parent_hwirq = msm_gpio_wakeirq;
-		pctrl->irq_chip.irq_eoi = irq_chip_eoi_parent;
 		/*
 		 * Let's skip handling the GPIOs, if the parent irqchip
 		 * is handling the direct connect IRQ of the GPIO.
@@ -1313,7 +1326,7 @@ static int msm_gpio_init(struct msm_pinctrl *pctrl)
 	}
 
 	girq = &chip->irq;
-	girq->chip = &pctrl->irq_chip;
+	gpio_irq_chip_set_chip(girq, &msm_gpio_irq_chip);
 	girq->parent_handler = msm_gpio_irq_handler;
 	girq->fwnode = pctrl->dev->fwnode;
 	girq->num_parents = 1;
-- 
2.34.1


_______________________________________________
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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH v2 07/10] pinctrl: msmgpio: Make the irqchip immutable

[Marc Zyngier]

Prevent gpiolib from messing with the irqchip by advertising
the irq_chip structure as immutable, making it const, and adding
the various calls that gpiolib relies upon.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 drivers/pinctrl/qcom/pinctrl-msm.c | 53 +++++++++++++++++++-----------
 1 file changed, 33 insertions(+), 20 deletions(-)

diff --git a/drivers/pinctrl/qcom/pinctrl-msm.c b/drivers/pinctrl/qcom/pinctrl-msm.c
index 966ea6622ff3..a2abfe987ab1 100644
--- a/drivers/pinctrl/qcom/pinctrl-msm.c
+++ b/drivers/pinctrl/qcom/pinctrl-msm.c
@@ -42,7 +42,6 @@
  * @chip:           gpiochip handle.
  * @desc:           pin controller descriptor
  * @restart_nb:     restart notifier block.
- * @irq_chip:       irq chip information
  * @irq:            parent irq for the TLMM irq_chip.
  * @intr_target_use_scm: route irq to application cpu using scm calls
  * @lock:           Spinlock to protect register resources as well
@@ -63,7 +62,6 @@ struct msm_pinctrl {
 	struct pinctrl_desc desc;
 	struct notifier_block restart_nb;
 
-	struct irq_chip irq_chip;
 	int irq;
 
 	bool intr_target_use_scm;
@@ -868,6 +866,8 @@ static void msm_gpio_irq_enable(struct irq_data *d)
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 	struct msm_pinctrl *pctrl = gpiochip_get_data(gc);
 
+	gpiochip_enable_irq(gc, d->hwirq);
+
 	if (d->parent_data)
 		irq_chip_enable_parent(d);
 
@@ -885,6 +885,8 @@ static void msm_gpio_irq_disable(struct irq_data *d)
 
 	if (!test_bit(d->hwirq, pctrl->skip_wake_irqs))
 		msm_gpio_irq_mask(d);
+
+	gpiochip_disable_irq(gc, d->hwirq);
 }
 
 /**
@@ -958,6 +960,14 @@ static void msm_gpio_irq_ack(struct irq_data *d)
 	raw_spin_unlock_irqrestore(&pctrl->lock, flags);
 }
 
+static void msm_gpio_irq_eoi(struct irq_data *d)
+{
+	d = d->parent_data;
+
+	if (d)
+		d->chip->irq_eoi(d);
+}
+
 static bool msm_gpio_needs_dual_edge_parent_workaround(struct irq_data *d,
 						       unsigned int type)
 {
@@ -1255,6 +1265,26 @@ static bool msm_gpio_needs_valid_mask(struct msm_pinctrl *pctrl)
 	return device_property_count_u16(pctrl->dev, "gpios") > 0;
 }
 
+static const struct irq_chip msm_gpio_irq_chip = {
+	.name			= "msmgpio",
+	.irq_enable		= msm_gpio_irq_enable,
+	.irq_disable		= msm_gpio_irq_disable,
+	.irq_mask		= msm_gpio_irq_mask,
+	.irq_unmask		= msm_gpio_irq_unmask,
+	.irq_ack		= msm_gpio_irq_ack,
+	.irq_eoi		= msm_gpio_irq_eoi,
+	.irq_set_type		= msm_gpio_irq_set_type,
+	.irq_set_wake		= msm_gpio_irq_set_wake,
+	.irq_request_resources	= msm_gpio_irq_reqres,
+	.irq_release_resources	= msm_gpio_irq_relres,
+	.irq_set_affinity	= msm_gpio_irq_set_affinity,
+	.irq_set_vcpu_affinity	= msm_gpio_irq_set_vcpu_affinity,
+	.flags			= (IRQCHIP_MASK_ON_SUSPEND |
+				   IRQCHIP_SET_TYPE_MASKED |
+				   IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND |
+				   IRQCHIP_IMMUTABLE),
+};
+
 static int msm_gpio_init(struct msm_pinctrl *pctrl)
 {
 	struct gpio_chip *chip;
@@ -1276,22 +1306,6 @@ static int msm_gpio_init(struct msm_pinctrl *pctrl)
 	if (msm_gpio_needs_valid_mask(pctrl))
 		chip->init_valid_mask = msm_gpio_init_valid_mask;
 
-	pctrl->irq_chip.name = "msmgpio";
-	pctrl->irq_chip.irq_enable = msm_gpio_irq_enable;
-	pctrl->irq_chip.irq_disable = msm_gpio_irq_disable;
-	pctrl->irq_chip.irq_mask = msm_gpio_irq_mask;
-	pctrl->irq_chip.irq_unmask = msm_gpio_irq_unmask;
-	pctrl->irq_chip.irq_ack = msm_gpio_irq_ack;
-	pctrl->irq_chip.irq_set_type = msm_gpio_irq_set_type;
-	pctrl->irq_chip.irq_set_wake = msm_gpio_irq_set_wake;
-	pctrl->irq_chip.irq_request_resources = msm_gpio_irq_reqres;
-	pctrl->irq_chip.irq_release_resources = msm_gpio_irq_relres;
-	pctrl->irq_chip.irq_set_affinity = msm_gpio_irq_set_affinity;
-	pctrl->irq_chip.irq_set_vcpu_affinity = msm_gpio_irq_set_vcpu_affinity;
-	pctrl->irq_chip.flags = IRQCHIP_MASK_ON_SUSPEND |
-				IRQCHIP_SET_TYPE_MASKED |
-				IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND;
-
 	np = of_parse_phandle(pctrl->dev->of_node, "wakeup-parent", 0);
 	if (np) {
 		chip->irq.parent_domain = irq_find_matching_host(np,
@@ -1300,7 +1314,6 @@ static int msm_gpio_init(struct msm_pinctrl *pctrl)
 		if (!chip->irq.parent_domain)
 			return -EPROBE_DEFER;
 		chip->irq.child_to_parent_hwirq = msm_gpio_wakeirq;
-		pctrl->irq_chip.irq_eoi = irq_chip_eoi_parent;
 		/*
 		 * Let's skip handling the GPIOs, if the parent irqchip
 		 * is handling the direct connect IRQ of the GPIO.
@@ -1313,7 +1326,7 @@ static int msm_gpio_init(struct msm_pinctrl *pctrl)
 	}
 
 	girq = &chip->irq;
-	girq->chip = &pctrl->irq_chip;
+	gpio_irq_chip_set_chip(girq, &msm_gpio_irq_chip);
 	girq->parent_handler = msm_gpio_irq_handler;
 	girq->fwnode = pctrl->dev->fwnode;
 	girq->num_parents = 1;
-- 
2.34.1

[PATCH v2 08/10] pinctrl: amd: Make the irqchip immutable

[Marc Zyngier]

Prevent gpiolib from messing with the irqchip by advertising
the irq_chip structure as immutable, making it const, and adding
the various calls that gpiolib relies upon.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 drivers/pinctrl/pinctrl-amd.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/pinctrl/pinctrl-amd.c b/drivers/pinctrl/pinctrl-amd.c
index 1a7d686494ff..0645c2c24f50 100644
--- a/drivers/pinctrl/pinctrl-amd.c
+++ b/drivers/pinctrl/pinctrl-amd.c
@@ -387,6 +387,8 @@ static void amd_gpio_irq_enable(struct irq_data *d)
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 	struct amd_gpio *gpio_dev = gpiochip_get_data(gc);
 
+	gpiochip_enable_irq(gc, d->hwirq);
+
 	raw_spin_lock_irqsave(&gpio_dev->lock, flags);
 	pin_reg = readl(gpio_dev->base + (d->hwirq)*4);
 	pin_reg |= BIT(INTERRUPT_ENABLE_OFF);
@@ -408,6 +410,8 @@ static void amd_gpio_irq_disable(struct irq_data *d)
 	pin_reg &= ~BIT(INTERRUPT_MASK_OFF);
 	writel(pin_reg, gpio_dev->base + (d->hwirq)*4);
 	raw_spin_unlock_irqrestore(&gpio_dev->lock, flags);
+
+	gpiochip_disable_irq(gc, d->hwirq);
 }
 
 static void amd_gpio_irq_mask(struct irq_data *d)
@@ -577,7 +581,7 @@ static void amd_irq_ack(struct irq_data *d)
 	*/
 }
 
-static struct irq_chip amd_gpio_irqchip = {
+static const struct irq_chip amd_gpio_irqchip = {
 	.name         = "amd_gpio",
 	.irq_ack      = amd_irq_ack,
 	.irq_enable   = amd_gpio_irq_enable,
@@ -593,7 +597,8 @@ static struct irq_chip amd_gpio_irqchip = {
 	 * the wake event. Otherwise the wake event will never clear and
 	 * prevent the system from suspending.
 	 */
-	.flags        = IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND,
+	.flags        = IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND | IRQCHIP_IMMUTABLE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
 };
 
 #define PIN_IRQ_PENDING	(BIT(INTERRUPT_STS_OFF) | BIT(WAKE_STS_OFF))
@@ -1026,7 +1031,7 @@ static int amd_gpio_probe(struct platform_device *pdev)
 	amd_gpio_irq_init(gpio_dev);
 
 	girq = &gpio_dev->gc.irq;
-	girq->chip = &amd_gpio_irqchip;
+	gpio_irq_chip_set_chip(girq, &amd_gpio_irqchip);
 	/* This will let us handle the parent IRQ in the driver */
 	girq->parent_handler = NULL;
 	girq->num_parents = 0;
-- 
2.34.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH v2 08/10] pinctrl: amd: Make the irqchip immutable

[Marc Zyngier]

Prevent gpiolib from messing with the irqchip by advertising
the irq_chip structure as immutable, making it const, and adding
the various calls that gpiolib relies upon.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 drivers/pinctrl/pinctrl-amd.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/pinctrl/pinctrl-amd.c b/drivers/pinctrl/pinctrl-amd.c
index 1a7d686494ff..0645c2c24f50 100644
--- a/drivers/pinctrl/pinctrl-amd.c
+++ b/drivers/pinctrl/pinctrl-amd.c
@@ -387,6 +387,8 @@ static void amd_gpio_irq_enable(struct irq_data *d)
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 	struct amd_gpio *gpio_dev = gpiochip_get_data(gc);
 
+	gpiochip_enable_irq(gc, d->hwirq);
+
 	raw_spin_lock_irqsave(&gpio_dev->lock, flags);
 	pin_reg = readl(gpio_dev->base + (d->hwirq)*4);
 	pin_reg |= BIT(INTERRUPT_ENABLE_OFF);
@@ -408,6 +410,8 @@ static void amd_gpio_irq_disable(struct irq_data *d)
 	pin_reg &= ~BIT(INTERRUPT_MASK_OFF);
 	writel(pin_reg, gpio_dev->base + (d->hwirq)*4);
 	raw_spin_unlock_irqrestore(&gpio_dev->lock, flags);
+
+	gpiochip_disable_irq(gc, d->hwirq);
 }
 
 static void amd_gpio_irq_mask(struct irq_data *d)
@@ -577,7 +581,7 @@ static void amd_irq_ack(struct irq_data *d)
 	*/
 }
 
-static struct irq_chip amd_gpio_irqchip = {
+static const struct irq_chip amd_gpio_irqchip = {
 	.name         = "amd_gpio",
 	.irq_ack      = amd_irq_ack,
 	.irq_enable   = amd_gpio_irq_enable,
@@ -593,7 +597,8 @@ static struct irq_chip amd_gpio_irqchip = {
 	 * the wake event. Otherwise the wake event will never clear and
 	 * prevent the system from suspending.
 	 */
-	.flags        = IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND,
+	.flags        = IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND | IRQCHIP_IMMUTABLE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
 };
 
 #define PIN_IRQ_PENDING	(BIT(INTERRUPT_STS_OFF) | BIT(WAKE_STS_OFF))
@@ -1026,7 +1031,7 @@ static int amd_gpio_probe(struct platform_device *pdev)
 	amd_gpio_irq_init(gpio_dev);
 
 	girq = &gpio_dev->gc.irq;
-	girq->chip = &amd_gpio_irqchip;
+	gpio_irq_chip_set_chip(girq, &amd_gpio_irqchip);
 	/* This will let us handle the parent IRQ in the driver */
 	girq->parent_handler = NULL;
 	girq->num_parents = 0;
-- 
2.34.1

[PATCH v2 09/10] gpio: Update TODO to mention immutable irq_chip structures

[Marc Zyngier]

5 drivers are converted, a few hundred to go. Definitely worth of
a TODO entry, in the hope that someone will notice it and do
a bulk update.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 drivers/gpio/TODO | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/drivers/gpio/TODO b/drivers/gpio/TODO
index b8b1473a5b1e..f87ff3fa8a53 100644
--- a/drivers/gpio/TODO
+++ b/drivers/gpio/TODO
@@ -178,3 +178,22 @@ discussed but the idea is to provide a low-level access point
 for debugging and hacking and to expose all lines without the
 need of any exporting. Also provide ample ammunition to shoot
 oneself in the foot, because this is debugfs after all.
+
+
+Moving over to immutable irq_chip structures
+
+Most of the gpio chips implementing interrupt support rely on gpiolib
+intercepting some of the irq_chip callbacks, preventing the structures
+from being made read-only and forcing duplication of structures that
+should otherwise be unique.
+
+The solution is to call into the gpiolib code when needed (resource
+management, enable/disable or unmask/mask callbacks), and to let the
+core code know about that by exposing a flag (IRQCHIP_IMMUTABLE) in
+the irq_chip structure. The irq_chip structure can then be made unique
+and const.
+
+A small number of drivers have been converted (pl061, tegra186, msm,
+amd, apple), and can be used as examples of how to proceed with this
+conversion. Note that drivers using the generic irqchip framework
+cannot be converted yet, but watch this space!
-- 
2.34.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH v2 09/10] gpio: Update TODO to mention immutable irq_chip structures

[Marc Zyngier]

5 drivers are converted, a few hundred to go. Definitely worth of
a TODO entry, in the hope that someone will notice it and do
a bulk update.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 drivers/gpio/TODO | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/drivers/gpio/TODO b/drivers/gpio/TODO
index b8b1473a5b1e..f87ff3fa8a53 100644
--- a/drivers/gpio/TODO
+++ b/drivers/gpio/TODO
@@ -178,3 +178,22 @@ discussed but the idea is to provide a low-level access point
 for debugging and hacking and to expose all lines without the
 need of any exporting. Also provide ample ammunition to shoot
 oneself in the foot, because this is debugfs after all.
+
+
+Moving over to immutable irq_chip structures
+
+Most of the gpio chips implementing interrupt support rely on gpiolib
+intercepting some of the irq_chip callbacks, preventing the structures
+from being made read-only and forcing duplication of structures that
+should otherwise be unique.
+
+The solution is to call into the gpiolib code when needed (resource
+management, enable/disable or unmask/mask callbacks), and to let the
+core code know about that by exposing a flag (IRQCHIP_IMMUTABLE) in
+the irq_chip structure. The irq_chip structure can then be made unique
+and const.
+
+A small number of drivers have been converted (pl061, tegra186, msm,
+amd, apple), and can be used as examples of how to proceed with this
+conversion. Note that drivers using the generic irqchip framework
+cannot be converted yet, but watch this space!
-- 
2.34.1

[PATCH v2 10/10] Documentation: Update the recommended pattern for GPIO irqchips

[Marc Zyngier]

Update the documentation to get rid of the per-gpio_irq_chip
irq_chip structure, and give examples of the new pattern.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 Documentation/driver-api/gpio/driver.rst | 175 ++++++++++++++++++-----
 1 file changed, 142 insertions(+), 33 deletions(-)

diff --git a/Documentation/driver-api/gpio/driver.rst b/Documentation/driver-api/gpio/driver.rst
index bbc53920d4dd..7e9f1167ea7d 100644
--- a/Documentation/driver-api/gpio/driver.rst
+++ b/Documentation/driver-api/gpio/driver.rst
@@ -417,30 +417,66 @@ struct gpio_irq_chip inside struct gpio_chip before adding the gpio_chip.
 If you do this, the additional irq_chip will be set up by gpiolib at the
 same time as setting up the rest of the GPIO functionality. The following
 is a typical example of a chained cascaded interrupt handler using
-the gpio_irq_chip:
+the gpio_irq_chip. Note how the mask/unmask (or disable/enable) functions
+call into the core gpiolib code:
 
 .. code-block:: c
 
-  /* Typical state container with dynamic irqchip */
+  /* Typical state container */
   struct my_gpio {
       struct gpio_chip gc;
-      struct irq_chip irq;
+  };
+
+  static void my_gpio_mask_irq(struct irq_data *d)
+  {
+      struct gpio_chip *gc = irq_desc_get_handler_data(d);
+
+      /*
+       * Perform any necessary action to mask the interrupt,
+       * and then call into the core code to synchronise the
+       * state.
+       */
+
+      gpiochip_disable_irq(gc, d->hwirq);
+  }
+
+  static void my_gpio_unmask_irq(struct irq_data *d)
+  {
+      struct gpio_chip *gc = irq_desc_get_handler_data(d);
+
+      gpiochip_disable_irq(gc, d->hwirq);
+
+      /*
+       * Perform any necessary action to unmask the interrupt,
+       * after having called into the core code to synchronise
+       * the state.
+       */
+  }
+
+  /*
+   * Statically populate the irqchip. Note that it is made const
+   * (further indicated by the IRQCHIP_IMMUTABLE flag), and that
+   * the GPIOCHIP_IRQ_RESOURCE_HELPER macro adds some extra
+   * callbacks to the structure.
+   */
+  static const struct irq_chip my_gpio_irq_chip = {
+      .name		= "my_gpio_irq",
+      .irq_ack		= my_gpio_ack_irq,
+      .irq_mask		= my_gpio_mask_irq,
+      .irq_unmask	= my_gpio_unmask_irq,
+      .irq_set_type	= my_gpio_set_irq_type,
+      .flags		= IRQCHIP_IMMUTABLE,
+      /* Provide the gpio resource callbacks */
+      GPIOCHIP_IRQ_RESOURCE_HELPERS,
   };
 
   int irq; /* from platform etc */
   struct my_gpio *g;
   struct gpio_irq_chip *girq;
 
-  /* Set up the irqchip dynamically */
-  g->irq.name = "my_gpio_irq";
-  g->irq.irq_ack = my_gpio_ack_irq;
-  g->irq.irq_mask = my_gpio_mask_irq;
-  g->irq.irq_unmask = my_gpio_unmask_irq;
-  g->irq.irq_set_type = my_gpio_set_irq_type;
-
   /* Get a pointer to the gpio_irq_chip */
   girq = &g->gc.irq;
-  girq->chip = &g->irq;
+  gpio_irq_chip_set_chip(girq, &my_gpio_irq_chip);
   girq->parent_handler = ftgpio_gpio_irq_handler;
   girq->num_parents = 1;
   girq->parents = devm_kcalloc(dev, 1, sizeof(*girq->parents),
@@ -458,23 +494,58 @@ the interrupt separately and go with it:
 
 .. code-block:: c
 
-  /* Typical state container with dynamic irqchip */
+  /* Typical state container */
   struct my_gpio {
       struct gpio_chip gc;
-      struct irq_chip irq;
+  };
+
+  static void my_gpio_mask_irq(struct irq_data *d)
+  {
+      struct gpio_chip *gc = irq_desc_get_handler_data(d);
+
+      /*
+       * Perform any necessary action to mask the interrupt,
+       * and then call into the core code to synchronise the
+       * state.
+       */
+
+      gpiochip_disable_irq(gc, d->hwirq);
+  }
+
+  static void my_gpio_unmask_irq(struct irq_data *d)
+  {
+      struct gpio_chip *gc = irq_desc_get_handler_data(d);
+
+      gpiochip_disable_irq(gc, d->hwirq);
+
+      /*
+       * Perform any necessary action to unmask the interrupt,
+       * after having called into the core code to synchronise
+       * the state.
+       */
+  }
+
+  /*
+   * Statically populate the irqchip. Note that it is made const
+   * (further indicated by the IRQCHIP_IMMUTABLE flag), and that
+   * the GPIOCHIP_IRQ_RESOURCE_HELPER macro adds some extra
+   * callbacks to the structure.
+   */
+  static const struct irq_chip my_gpio_irq_chip = {
+      .name		= "my_gpio_irq",
+      .irq_ack		= my_gpio_ack_irq,
+      .irq_mask		= my_gpio_mask_irq,
+      .irq_unmask	= my_gpio_unmask_irq,
+      .irq_set_type	= my_gpio_set_irq_type,
+      .flags		= IRQCHIP_IMMUTABLE,
+      /* Provide the gpio resource callbacks */
+      GPIOCHIP_IRQ_RESOURCE_HELPERS,
   };
 
   int irq; /* from platform etc */
   struct my_gpio *g;
   struct gpio_irq_chip *girq;
 
-  /* Set up the irqchip dynamically */
-  g->irq.name = "my_gpio_irq";
-  g->irq.irq_ack = my_gpio_ack_irq;
-  g->irq.irq_mask = my_gpio_mask_irq;
-  g->irq.irq_unmask = my_gpio_unmask_irq;
-  g->irq.irq_set_type = my_gpio_set_irq_type;
-
   ret = devm_request_threaded_irq(dev, irq, NULL,
 		irq_thread_fn, IRQF_ONESHOT, "my-chip", g);
   if (ret < 0)
@@ -482,7 +553,7 @@ the interrupt separately and go with it:
 
   /* Get a pointer to the gpio_irq_chip */
   girq = &g->gc.irq;
-  girq->chip = &g->irq;
+  gpio_irq_chip_set_chip(girq, &my_gpio_irq_chip);
   /* This will let us handle the parent IRQ in the driver */
   girq->parent_handler = NULL;
   girq->num_parents = 0;
@@ -500,24 +571,61 @@ In this case the typical set-up will look like this:
   /* Typical state container with dynamic irqchip */
   struct my_gpio {
       struct gpio_chip gc;
-      struct irq_chip irq;
       struct fwnode_handle *fwnode;
   };
 
-  int irq; /* from platform etc */
+  static void my_gpio_mask_irq(struct irq_data *d)
+  {
+      struct gpio_chip *gc = irq_desc_get_handler_data(d);
+
+      /*
+       * Perform any necessary action to mask the interrupt,
+       * and then call into the core code to synchronise the
+       * state.
+       */
+
+      gpiochip_disable_irq(gc, d->hwirq);
+      irq_mask_mask_parent(d);
+  }
+
+  static void my_gpio_unmask_irq(struct irq_data *d)
+  {
+      struct gpio_chip *gc = irq_desc_get_handler_data(d);
+
+      gpiochip_disable_irq(gc, d->hwirq);
+
+      /*
+       * Perform any necessary action to unmask the interrupt,
+       * after having called into the core code to synchronise
+       * the state.
+       */
+
+      irq_mask_unmask_parent(d);
+  }
+
+  /*
+   * Statically populate the irqchip. Note that it is made const
+   * (further indicated by the IRQCHIP_IMMUTABLE flag), and that
+   * the GPIOCHIP_IRQ_RESOURCE_HELPER macro adds some extra
+   * callbacks to the structure.
+   */
+  static const struct irq_chip my_gpio_irq_chip = {
+      .name		= "my_gpio_irq",
+      .irq_ack		= my_gpio_ack_irq,
+      .irq_mask		= my_gpio_mask_irq,
+      .irq_unmask	= my_gpio_unmask_irq,
+      .irq_set_type	= my_gpio_set_irq_type,
+      .flags		= IRQCHIP_IMMUTABLE,
+      /* Provide the gpio resource callbacks */
+      GPIOCHIP_IRQ_RESOURCE_HELPERS,
+  };
+
   struct my_gpio *g;
   struct gpio_irq_chip *girq;
 
-  /* Set up the irqchip dynamically */
-  g->irq.name = "my_gpio_irq";
-  g->irq.irq_ack = my_gpio_ack_irq;
-  g->irq.irq_mask = my_gpio_mask_irq;
-  g->irq.irq_unmask = my_gpio_unmask_irq;
-  g->irq.irq_set_type = my_gpio_set_irq_type;
-
   /* Get a pointer to the gpio_irq_chip */
   girq = &g->gc.irq;
-  girq->chip = &g->irq;
+  gpio_irq_chip_set_chip(girq, &my_gpio_irq_chip);
   girq->default_type = IRQ_TYPE_NONE;
   girq->handler = handle_bad_irq;
   girq->fwnode = g->fwnode;
@@ -605,8 +713,9 @@ When implementing an irqchip inside a GPIO driver, these two functions should
 typically be called in the .irq_disable() and .irq_enable() callbacks from the
 irqchip.
 
-When using the gpiolib irqchip helpers, these callbacks are automatically
-assigned.
+When IRQCHIP_IMMUTABLE is not advertised by the irqchip, these callbacks
+are automatically assigned. This behaviour is deprecated and on its way
+to be removed from the kernel.
 
 
 Real-Time compliance for GPIO IRQ chips
-- 
2.34.1


_______________________________________________
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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH v2 10/10] Documentation: Update the recommended pattern for GPIO irqchips

[Marc Zyngier]

Update the documentation to get rid of the per-gpio_irq_chip
irq_chip structure, and give examples of the new pattern.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 Documentation/driver-api/gpio/driver.rst | 175 ++++++++++++++++++-----
 1 file changed, 142 insertions(+), 33 deletions(-)

diff --git a/Documentation/driver-api/gpio/driver.rst b/Documentation/driver-api/gpio/driver.rst
index bbc53920d4dd..7e9f1167ea7d 100644
--- a/Documentation/driver-api/gpio/driver.rst
+++ b/Documentation/driver-api/gpio/driver.rst
@@ -417,30 +417,66 @@ struct gpio_irq_chip inside struct gpio_chip before adding the gpio_chip.
 If you do this, the additional irq_chip will be set up by gpiolib at the
 same time as setting up the rest of the GPIO functionality. The following
 is a typical example of a chained cascaded interrupt handler using
-the gpio_irq_chip:
+the gpio_irq_chip. Note how the mask/unmask (or disable/enable) functions
+call into the core gpiolib code:
 
 .. code-block:: c
 
-  /* Typical state container with dynamic irqchip */
+  /* Typical state container */
   struct my_gpio {
       struct gpio_chip gc;
-      struct irq_chip irq;
+  };
+
+  static void my_gpio_mask_irq(struct irq_data *d)
+  {
+      struct gpio_chip *gc = irq_desc_get_handler_data(d);
+
+      /*
+       * Perform any necessary action to mask the interrupt,
+       * and then call into the core code to synchronise the
+       * state.
+       */
+
+      gpiochip_disable_irq(gc, d->hwirq);
+  }
+
+  static void my_gpio_unmask_irq(struct irq_data *d)
+  {
+      struct gpio_chip *gc = irq_desc_get_handler_data(d);
+
+      gpiochip_disable_irq(gc, d->hwirq);
+
+      /*
+       * Perform any necessary action to unmask the interrupt,
+       * after having called into the core code to synchronise
+       * the state.
+       */
+  }
+
+  /*
+   * Statically populate the irqchip. Note that it is made const
+   * (further indicated by the IRQCHIP_IMMUTABLE flag), and that
+   * the GPIOCHIP_IRQ_RESOURCE_HELPER macro adds some extra
+   * callbacks to the structure.
+   */
+  static const struct irq_chip my_gpio_irq_chip = {
+      .name		= "my_gpio_irq",
+      .irq_ack		= my_gpio_ack_irq,
+      .irq_mask		= my_gpio_mask_irq,
+      .irq_unmask	= my_gpio_unmask_irq,
+      .irq_set_type	= my_gpio_set_irq_type,
+      .flags		= IRQCHIP_IMMUTABLE,
+      /* Provide the gpio resource callbacks */
+      GPIOCHIP_IRQ_RESOURCE_HELPERS,
   };
 
   int irq; /* from platform etc */
   struct my_gpio *g;
   struct gpio_irq_chip *girq;
 
-  /* Set up the irqchip dynamically */
-  g->irq.name = "my_gpio_irq";
-  g->irq.irq_ack = my_gpio_ack_irq;
-  g->irq.irq_mask = my_gpio_mask_irq;
-  g->irq.irq_unmask = my_gpio_unmask_irq;
-  g->irq.irq_set_type = my_gpio_set_irq_type;
-
   /* Get a pointer to the gpio_irq_chip */
   girq = &g->gc.irq;
-  girq->chip = &g->irq;
+  gpio_irq_chip_set_chip(girq, &my_gpio_irq_chip);
   girq->parent_handler = ftgpio_gpio_irq_handler;
   girq->num_parents = 1;
   girq->parents = devm_kcalloc(dev, 1, sizeof(*girq->parents),
@@ -458,23 +494,58 @@ the interrupt separately and go with it:
 
 .. code-block:: c
 
-  /* Typical state container with dynamic irqchip */
+  /* Typical state container */
   struct my_gpio {
       struct gpio_chip gc;
-      struct irq_chip irq;
+  };
+
+  static void my_gpio_mask_irq(struct irq_data *d)
+  {
+      struct gpio_chip *gc = irq_desc_get_handler_data(d);
+
+      /*
+       * Perform any necessary action to mask the interrupt,
+       * and then call into the core code to synchronise the
+       * state.
+       */
+
+      gpiochip_disable_irq(gc, d->hwirq);
+  }
+
+  static void my_gpio_unmask_irq(struct irq_data *d)
+  {
+      struct gpio_chip *gc = irq_desc_get_handler_data(d);
+
+      gpiochip_disable_irq(gc, d->hwirq);
+
+      /*
+       * Perform any necessary action to unmask the interrupt,
+       * after having called into the core code to synchronise
+       * the state.
+       */
+  }
+
+  /*
+   * Statically populate the irqchip. Note that it is made const
+   * (further indicated by the IRQCHIP_IMMUTABLE flag), and that
+   * the GPIOCHIP_IRQ_RESOURCE_HELPER macro adds some extra
+   * callbacks to the structure.
+   */
+  static const struct irq_chip my_gpio_irq_chip = {
+      .name		= "my_gpio_irq",
+      .irq_ack		= my_gpio_ack_irq,
+      .irq_mask		= my_gpio_mask_irq,
+      .irq_unmask	= my_gpio_unmask_irq,
+      .irq_set_type	= my_gpio_set_irq_type,
+      .flags		= IRQCHIP_IMMUTABLE,
+      /* Provide the gpio resource callbacks */
+      GPIOCHIP_IRQ_RESOURCE_HELPERS,
   };
 
   int irq; /* from platform etc */
   struct my_gpio *g;
   struct gpio_irq_chip *girq;
 
-  /* Set up the irqchip dynamically */
-  g->irq.name = "my_gpio_irq";
-  g->irq.irq_ack = my_gpio_ack_irq;
-  g->irq.irq_mask = my_gpio_mask_irq;
-  g->irq.irq_unmask = my_gpio_unmask_irq;
-  g->irq.irq_set_type = my_gpio_set_irq_type;
-
   ret = devm_request_threaded_irq(dev, irq, NULL,
 		irq_thread_fn, IRQF_ONESHOT, "my-chip", g);
   if (ret < 0)
@@ -482,7 +553,7 @@ the interrupt separately and go with it:
 
   /* Get a pointer to the gpio_irq_chip */
   girq = &g->gc.irq;
-  girq->chip = &g->irq;
+  gpio_irq_chip_set_chip(girq, &my_gpio_irq_chip);
   /* This will let us handle the parent IRQ in the driver */
   girq->parent_handler = NULL;
   girq->num_parents = 0;
@@ -500,24 +571,61 @@ In this case the typical set-up will look like this:
   /* Typical state container with dynamic irqchip */
   struct my_gpio {
       struct gpio_chip gc;
-      struct irq_chip irq;
       struct fwnode_handle *fwnode;
   };
 
-  int irq; /* from platform etc */
+  static void my_gpio_mask_irq(struct irq_data *d)
+  {
+      struct gpio_chip *gc = irq_desc_get_handler_data(d);
+
+      /*
+       * Perform any necessary action to mask the interrupt,
+       * and then call into the core code to synchronise the
+       * state.
+       */
+
+      gpiochip_disable_irq(gc, d->hwirq);
+      irq_mask_mask_parent(d);
+  }
+
+  static void my_gpio_unmask_irq(struct irq_data *d)
+  {
+      struct gpio_chip *gc = irq_desc_get_handler_data(d);
+
+      gpiochip_disable_irq(gc, d->hwirq);
+
+      /*
+       * Perform any necessary action to unmask the interrupt,
+       * after having called into the core code to synchronise
+       * the state.
+       */
+
+      irq_mask_unmask_parent(d);
+  }
+
+  /*
+   * Statically populate the irqchip. Note that it is made const
+   * (further indicated by the IRQCHIP_IMMUTABLE flag), and that
+   * the GPIOCHIP_IRQ_RESOURCE_HELPER macro adds some extra
+   * callbacks to the structure.
+   */
+  static const struct irq_chip my_gpio_irq_chip = {
+      .name		= "my_gpio_irq",
+      .irq_ack		= my_gpio_ack_irq,
+      .irq_mask		= my_gpio_mask_irq,
+      .irq_unmask	= my_gpio_unmask_irq,
+      .irq_set_type	= my_gpio_set_irq_type,
+      .flags		= IRQCHIP_IMMUTABLE,
+      /* Provide the gpio resource callbacks */
+      GPIOCHIP_IRQ_RESOURCE_HELPERS,
+  };
+
   struct my_gpio *g;
   struct gpio_irq_chip *girq;
 
-  /* Set up the irqchip dynamically */
-  g->irq.name = "my_gpio_irq";
-  g->irq.irq_ack = my_gpio_ack_irq;
-  g->irq.irq_mask = my_gpio_mask_irq;
-  g->irq.irq_unmask = my_gpio_unmask_irq;
-  g->irq.irq_set_type = my_gpio_set_irq_type;
-
   /* Get a pointer to the gpio_irq_chip */
   girq = &g->gc.irq;
-  girq->chip = &g->irq;
+  gpio_irq_chip_set_chip(girq, &my_gpio_irq_chip);
   girq->default_type = IRQ_TYPE_NONE;
   girq->handler = handle_bad_irq;
   girq->fwnode = g->fwnode;
@@ -605,8 +713,9 @@ When implementing an irqchip inside a GPIO driver, these two functions should
 typically be called in the .irq_disable() and .irq_enable() callbacks from the
 irqchip.
 
-When using the gpiolib irqchip helpers, these callbacks are automatically
-assigned.
+When IRQCHIP_IMMUTABLE is not advertised by the irqchip, these callbacks
+are automatically assigned. This behaviour is deprecated and on its way
+to be removed from the kernel.
 
 
 Real-Time compliance for GPIO IRQ chips
-- 
2.34.1

Re: [PATCH v2 10/10] Documentation: Update the recommended pattern for GPIO irqchips

[Andy Shevchenko]

On Wed, Apr 6, 2022 at 1:57 PM Marc Zyngier <maz@kernel.org> wrote:
>
> Update the documentation to get rid of the per-gpio_irq_chip
> irq_chip structure, and give examples of the new pattern.

...

> +  static void my_gpio_mask_irq(struct irq_data *d)
> +  {
> +      struct gpio_chip *gc = irq_desc_get_handler_data(d);
> +
> +      /*
> +       * Perform any necessary action to mask the interrupt,
> +       * and then call into the core code to synchronise the
> +       * state.
> +       */
> +
> +      gpiochip_disable_irq(gc, d->hwirq);

(1)

> +  }
> +
> +  static void my_gpio_unmask_irq(struct irq_data *d)
> +  {
> +      struct gpio_chip *gc = irq_desc_get_handler_data(d);

> +      gpiochip_disable_irq(gc, d->hwirq);

(2)

> +      /*
> +       * Perform any necessary action to unmask the interrupt,
> +       * after having called into the core code to synchronise
> +       * the state.
> +       */
> +  }

If (1) and (2) being the same is not a mistake (typo) it probably
needs additional explanation.

...

> +  static void my_gpio_mask_irq(struct irq_data *d)
> +  {
> +      struct gpio_chip *gc = irq_desc_get_handler_data(d);
> +
> +      /*
> +       * Perform any necessary action to mask the interrupt,
> +       * and then call into the core code to synchronise the
> +       * state.
> +       */

> +      gpiochip_disable_irq(gc, d->hwirq);

(3)

> +  }
> +
> +  static void my_gpio_unmask_irq(struct irq_data *d)
> +  {
> +      struct gpio_chip *gc = irq_desc_get_handler_data(d);

> +      gpiochip_disable_irq(gc, d->hwirq);

(4)

> +      /*
> +       * Perform any necessary action to unmask the interrupt,
> +       * after having called into the core code to synchronise
> +       * the state.
> +       */
> +  }

Ditto for (3) & (4).

...

> +  static void my_gpio_mask_irq(struct irq_data *d)
> +  {
> +      struct gpio_chip *gc = irq_desc_get_handler_data(d);
> +
> +      /*
> +       * Perform any necessary action to mask the interrupt,
> +       * and then call into the core code to synchronise the
> +       * state.
> +       */
> +
> +      gpiochip_disable_irq(gc, d->hwirq);

(5)

> +      irq_mask_mask_parent(d);
> +  }
> +
> +  static void my_gpio_unmask_irq(struct irq_data *d)
> +  {
> +      struct gpio_chip *gc = irq_desc_get_handler_data(d);

> +      gpiochip_disable_irq(gc, d->hwirq);

(6)

> +      /*
> +       * Perform any necessary action to unmask the interrupt,
> +       * after having called into the core code to synchronise
> +       * the state.
> +       */
> +
> +      irq_mask_unmask_parent(d);
> +  }

Ditto for (5) & (6).

--
With Best Regards,
Andy Shevchenko

Re: [PATCH v2 10/10] Documentation: Update the recommended pattern for GPIO irqchips

[Andy Shevchenko]

On Wed, Apr 6, 2022 at 1:57 PM Marc Zyngier <maz@kernel.org> wrote:
>
> Update the documentation to get rid of the per-gpio_irq_chip
> irq_chip structure, and give examples of the new pattern.

...

> +  static void my_gpio_mask_irq(struct irq_data *d)
> +  {
> +      struct gpio_chip *gc = irq_desc_get_handler_data(d);
> +
> +      /*
> +       * Perform any necessary action to mask the interrupt,
> +       * and then call into the core code to synchronise the
> +       * state.
> +       */
> +
> +      gpiochip_disable_irq(gc, d->hwirq);

(1)

> +  }
> +
> +  static void my_gpio_unmask_irq(struct irq_data *d)
> +  {
> +      struct gpio_chip *gc = irq_desc_get_handler_data(d);

> +      gpiochip_disable_irq(gc, d->hwirq);

(2)

> +      /*
> +       * Perform any necessary action to unmask the interrupt,
> +       * after having called into the core code to synchronise
> +       * the state.
> +       */
> +  }

If (1) and (2) being the same is not a mistake (typo) it probably
needs additional explanation.

...

> +  static void my_gpio_mask_irq(struct irq_data *d)
> +  {
> +      struct gpio_chip *gc = irq_desc_get_handler_data(d);
> +
> +      /*
> +       * Perform any necessary action to mask the interrupt,
> +       * and then call into the core code to synchronise the
> +       * state.
> +       */

> +      gpiochip_disable_irq(gc, d->hwirq);

(3)

> +  }
> +
> +  static void my_gpio_unmask_irq(struct irq_data *d)
> +  {
> +      struct gpio_chip *gc = irq_desc_get_handler_data(d);

> +      gpiochip_disable_irq(gc, d->hwirq);

(4)

> +      /*
> +       * Perform any necessary action to unmask the interrupt,
> +       * after having called into the core code to synchronise
> +       * the state.
> +       */
> +  }

Ditto for (3) & (4).

...

> +  static void my_gpio_mask_irq(struct irq_data *d)
> +  {
> +      struct gpio_chip *gc = irq_desc_get_handler_data(d);
> +
> +      /*
> +       * Perform any necessary action to mask the interrupt,
> +       * and then call into the core code to synchronise the
> +       * state.
> +       */
> +
> +      gpiochip_disable_irq(gc, d->hwirq);

(5)

> +      irq_mask_mask_parent(d);
> +  }
> +
> +  static void my_gpio_unmask_irq(struct irq_data *d)
> +  {
> +      struct gpio_chip *gc = irq_desc_get_handler_data(d);

> +      gpiochip_disable_irq(gc, d->hwirq);

(6)

> +      /*
> +       * Perform any necessary action to unmask the interrupt,
> +       * after having called into the core code to synchronise
> +       * the state.
> +       */
> +
> +      irq_mask_unmask_parent(d);
> +  }

Ditto for (5) & (6).

--
With Best Regards,
Andy Shevchenko

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Re: [PATCH v2 00/10] gpiolib: Handle immutable irq_chip structures

[Andy Shevchenko]

On Wed, Apr 6, 2022 at 2:06 PM Marc Zyngier <maz@kernel.org> wrote:
>
> This is a followup from [1].
>
> I recently realised that the gpiolib play ugly tricks on the
> unsuspecting irq_chip structures by patching the callbacks.
>
> Not only this breaks when an irq_chip structure is made const (which
> really should be the default case), but it also forces this structure
> to be copied at nauseam for each instance of the GPIO block, which is
> a waste of memory.
>
> My current approach is to add a new irq_chip flag (IRQCHIP_IMMUTABLE)
> which does what it says on the tin: don't you dare writing to them.
> Gpiolib is further updated not to install its own callbacks, and it
> becomes the responsibility of the driver to call into the gpiolib when
> required. This is similar to what we do for other subsystems such as
> PCI-MSI.
>
> 5 drivers are updated to this new model: M1, QC, Tegra, pl061 and AMD
> (as I actively use them) keeping a single irq_chip structure, marking
> it const, and exposing the new flag.
>
> Nothing breaks, the volume of change is small, the memory usage goes
> down and we have fewer callbacks that can be used as attack vectors.
> What's not to love?

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
for the patches 1-3,9 and 10 after clarifying one example case.

> * From v1 [1]:
>   - pl061 and AMD drivers converted
>   - New helpers to keep the changes small
>   - New warning for non-converted drivers
>   - Documentation and TODO updates
>
> [1] https://lore.kernel.org/r/20220223154405.54912-1-maz@kernel.org
>
> Marc Zyngier (10):
>   gpio: Don't fiddle with irqchips marked as immutable
>   gpio: Expose the gpiochip_irq_re[ql]res helpers
>   gpio: Add helpers to ease the transition towards immutable irq_chip
>   gpio: tegra186: Make the irqchip immutable
>   gpio: pl061: Make the irqchip immutable
>   pinctrl: apple-gpio: Make the irqchip immutable
>   pinctrl: msmgpio: Make the irqchip immutable
>   pinctrl: amd: Make the irqchip immutable
>   gpio: Update TODO to mention immutable irq_chip structures
>   Documentation: Update the recommended pattern for GPIO irqchips
>
>  Documentation/driver-api/gpio/driver.rst | 175 ++++++++++++++++++-----
>  drivers/gpio/TODO                        |  19 +++
>  drivers/gpio/gpio-pl061.c                |  32 +++--
>  drivers/gpio/gpio-tegra186.c             |  32 +++--
>  drivers/gpio/gpiolib.c                   |  13 +-
>  drivers/pinctrl/pinctrl-amd.c            |  11 +-
>  drivers/pinctrl/pinctrl-apple-gpio.c     |  29 ++--
>  drivers/pinctrl/qcom/pinctrl-msm.c       |  53 ++++---
>  include/linux/gpio/driver.h              |  16 +++
>  include/linux/irq.h                      |   2 +
>  kernel/irq/debugfs.c                     |   1 +
>  11 files changed, 293 insertions(+), 90 deletions(-)
>
> --
> 2.34.1
>


-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v2 00/10] gpiolib: Handle immutable irq_chip structures

[Andy Shevchenko]

On Wed, Apr 6, 2022 at 2:06 PM Marc Zyngier <maz@kernel.org> wrote:
>
> This is a followup from [1].
>
> I recently realised that the gpiolib play ugly tricks on the
> unsuspecting irq_chip structures by patching the callbacks.
>
> Not only this breaks when an irq_chip structure is made const (which
> really should be the default case), but it also forces this structure
> to be copied at nauseam for each instance of the GPIO block, which is
> a waste of memory.
>
> My current approach is to add a new irq_chip flag (IRQCHIP_IMMUTABLE)
> which does what it says on the tin: don't you dare writing to them.
> Gpiolib is further updated not to install its own callbacks, and it
> becomes the responsibility of the driver to call into the gpiolib when
> required. This is similar to what we do for other subsystems such as
> PCI-MSI.
>
> 5 drivers are updated to this new model: M1, QC, Tegra, pl061 and AMD
> (as I actively use them) keeping a single irq_chip structure, marking
> it const, and exposing the new flag.
>
> Nothing breaks, the volume of change is small, the memory usage goes
> down and we have fewer callbacks that can be used as attack vectors.
> What's not to love?

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
for the patches 1-3,9 and 10 after clarifying one example case.

> * From v1 [1]:
>   - pl061 and AMD drivers converted
>   - New helpers to keep the changes small
>   - New warning for non-converted drivers
>   - Documentation and TODO updates
>
> [1] https://lore.kernel.org/r/20220223154405.54912-1-maz@kernel.org
>
> Marc Zyngier (10):
>   gpio: Don't fiddle with irqchips marked as immutable
>   gpio: Expose the gpiochip_irq_re[ql]res helpers
>   gpio: Add helpers to ease the transition towards immutable irq_chip
>   gpio: tegra186: Make the irqchip immutable
>   gpio: pl061: Make the irqchip immutable
>   pinctrl: apple-gpio: Make the irqchip immutable
>   pinctrl: msmgpio: Make the irqchip immutable
>   pinctrl: amd: Make the irqchip immutable
>   gpio: Update TODO to mention immutable irq_chip structures
>   Documentation: Update the recommended pattern for GPIO irqchips
>
>  Documentation/driver-api/gpio/driver.rst | 175 ++++++++++++++++++-----
>  drivers/gpio/TODO                        |  19 +++
>  drivers/gpio/gpio-pl061.c                |  32 +++--
>  drivers/gpio/gpio-tegra186.c             |  32 +++--
>  drivers/gpio/gpiolib.c                   |  13 +-
>  drivers/pinctrl/pinctrl-amd.c            |  11 +-
>  drivers/pinctrl/pinctrl-apple-gpio.c     |  29 ++--
>  drivers/pinctrl/qcom/pinctrl-msm.c       |  53 ++++---
>  include/linux/gpio/driver.h              |  16 +++
>  include/linux/irq.h                      |   2 +
>  kernel/irq/debugfs.c                     |   1 +
>  11 files changed, 293 insertions(+), 90 deletions(-)
>
> --
> 2.34.1
>


-- 
With Best Regards,
Andy Shevchenko

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Re: [PATCH v2 10/10] Documentation: Update the recommended pattern for GPIO irqchips

[Marc Zyngier]

On 2022-04-08 12:33, Andy Shevchenko wrote:
> On Wed, Apr 6, 2022 at 1:57 PM Marc Zyngier <maz@kernel.org> wrote:
>> 
>> Update the documentation to get rid of the per-gpio_irq_chip
>> irq_chip structure, and give examples of the new pattern.
> 
> ...
> 
>> +  static void my_gpio_mask_irq(struct irq_data *d)
>> +  {
>> +      struct gpio_chip *gc = irq_desc_get_handler_data(d);
>> +
>> +      /*
>> +       * Perform any necessary action to mask the interrupt,
>> +       * and then call into the core code to synchronise the
>> +       * state.
>> +       */
>> +
>> +      gpiochip_disable_irq(gc, d->hwirq);
> 
> (1)
> 
>> +  }
>> +
>> +  static void my_gpio_unmask_irq(struct irq_data *d)
>> +  {
>> +      struct gpio_chip *gc = irq_desc_get_handler_data(d);
> 
>> +      gpiochip_disable_irq(gc, d->hwirq);
> 
> (2)
> 
>> +      /*
>> +       * Perform any necessary action to unmask the interrupt,
>> +       * after having called into the core code to synchronise
>> +       * the state.
>> +       */
>> +  }
> 
> If (1) and (2) being the same is not a mistake (typo) it probably
> needs additional explanation.

Well spotted, this is definitely a copy-paste issue.
I'll fix this locally.

Thanks,

         M.
-- 
Jazz is not dead. It just smells funny...

Re: [PATCH v2 10/10] Documentation: Update the recommended pattern for GPIO irqchips

[Marc Zyngier]

On 2022-04-08 12:33, Andy Shevchenko wrote:
> On Wed, Apr 6, 2022 at 1:57 PM Marc Zyngier <maz@kernel.org> wrote:
>> 
>> Update the documentation to get rid of the per-gpio_irq_chip
>> irq_chip structure, and give examples of the new pattern.
> 
> ...
> 
>> +  static void my_gpio_mask_irq(struct irq_data *d)
>> +  {
>> +      struct gpio_chip *gc = irq_desc_get_handler_data(d);
>> +
>> +      /*
>> +       * Perform any necessary action to mask the interrupt,
>> +       * and then call into the core code to synchronise the
>> +       * state.
>> +       */
>> +
>> +      gpiochip_disable_irq(gc, d->hwirq);
> 
> (1)
> 
>> +  }
>> +
>> +  static void my_gpio_unmask_irq(struct irq_data *d)
>> +  {
>> +      struct gpio_chip *gc = irq_desc_get_handler_data(d);
> 
>> +      gpiochip_disable_irq(gc, d->hwirq);
> 
> (2)
> 
>> +      /*
>> +       * Perform any necessary action to unmask the interrupt,
>> +       * after having called into the core code to synchronise
>> +       * the state.
>> +       */
>> +  }
> 
> If (1) and (2) being the same is not a mistake (typo) it probably
> needs additional explanation.

Well spotted, this is definitely a copy-paste issue.
I'll fix this locally.

Thanks,

         M.
-- 
Jazz is not dead. It just smells funny...

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Re: [PATCH v2 00/10] gpiolib: Handle immutable irq_chip structures

[Bartosz Golaszewski]

On Tue, Apr 5, 2022 at 3:55 PM Marc Zyngier <maz@kernel.org> wrote:
>
> This is a followup from [1].
>
> I recently realised that the gpiolib play ugly tricks on the
> unsuspecting irq_chip structures by patching the callbacks.
>
> Not only this breaks when an irq_chip structure is made const (which
> really should be the default case), but it also forces this structure
> to be copied at nauseam for each instance of the GPIO block, which is
> a waste of memory.
>
> My current approach is to add a new irq_chip flag (IRQCHIP_IMMUTABLE)
> which does what it says on the tin: don't you dare writing to them.
> Gpiolib is further updated not to install its own callbacks, and it
> becomes the responsibility of the driver to call into the gpiolib when
> required. This is similar to what we do for other subsystems such as
> PCI-MSI.
>
> 5 drivers are updated to this new model: M1, QC, Tegra, pl061 and AMD
> (as I actively use them) keeping a single irq_chip structure, marking
> it const, and exposing the new flag.
>
> Nothing breaks, the volume of change is small, the memory usage goes
> down and we have fewer callbacks that can be used as attack vectors.
> What's not to love?
>
> * From v1 [1]:
>   - pl061 and AMD drivers converted
>   - New helpers to keep the changes small
>   - New warning for non-converted drivers
>   - Documentation and TODO updates
>
> [1] https://lore.kernel.org/r/20220223154405.54912-1-maz@kernel.org
>
> Marc Zyngier (10):
>   gpio: Don't fiddle with irqchips marked as immutable
>   gpio: Expose the gpiochip_irq_re[ql]res helpers
>   gpio: Add helpers to ease the transition towards immutable irq_chip
>   gpio: tegra186: Make the irqchip immutable
>   gpio: pl061: Make the irqchip immutable
>   pinctrl: apple-gpio: Make the irqchip immutable
>   pinctrl: msmgpio: Make the irqchip immutable
>   pinctrl: amd: Make the irqchip immutable
>   gpio: Update TODO to mention immutable irq_chip structures
>   Documentation: Update the recommended pattern for GPIO irqchips
>
>  Documentation/driver-api/gpio/driver.rst | 175 ++++++++++++++++++-----
>  drivers/gpio/TODO                        |  19 +++
>  drivers/gpio/gpio-pl061.c                |  32 +++--
>  drivers/gpio/gpio-tegra186.c             |  32 +++--
>  drivers/gpio/gpiolib.c                   |  13 +-
>  drivers/pinctrl/pinctrl-amd.c            |  11 +-
>  drivers/pinctrl/pinctrl-apple-gpio.c     |  29 ++--
>  drivers/pinctrl/qcom/pinctrl-msm.c       |  53 ++++---
>  include/linux/gpio/driver.h              |  16 +++
>  include/linux/irq.h                      |   2 +
>  kernel/irq/debugfs.c                     |   1 +
>  11 files changed, 293 insertions(+), 90 deletions(-)
>
> --
> 2.34.1
>

This may be coming too late but for the GPIO part:

Reviewed-by: Bartosz Golaszewski <brgl@bgdev.pl>

Re: [PATCH v2 00/10] gpiolib: Handle immutable irq_chip structures

[Bartosz Golaszewski]

On Tue, Apr 5, 2022 at 3:55 PM Marc Zyngier <maz@kernel.org> wrote:
>
> This is a followup from [1].
>
> I recently realised that the gpiolib play ugly tricks on the
> unsuspecting irq_chip structures by patching the callbacks.
>
> Not only this breaks when an irq_chip structure is made const (which
> really should be the default case), but it also forces this structure
> to be copied at nauseam for each instance of the GPIO block, which is
> a waste of memory.
>
> My current approach is to add a new irq_chip flag (IRQCHIP_IMMUTABLE)
> which does what it says on the tin: don't you dare writing to them.
> Gpiolib is further updated not to install its own callbacks, and it
> becomes the responsibility of the driver to call into the gpiolib when
> required. This is similar to what we do for other subsystems such as
> PCI-MSI.
>
> 5 drivers are updated to this new model: M1, QC, Tegra, pl061 and AMD
> (as I actively use them) keeping a single irq_chip structure, marking
> it const, and exposing the new flag.
>
> Nothing breaks, the volume of change is small, the memory usage goes
> down and we have fewer callbacks that can be used as attack vectors.
> What's not to love?
>
> * From v1 [1]:
>   - pl061 and AMD drivers converted
>   - New helpers to keep the changes small
>   - New warning for non-converted drivers
>   - Documentation and TODO updates
>
> [1] https://lore.kernel.org/r/20220223154405.54912-1-maz@kernel.org
>
> Marc Zyngier (10):
>   gpio: Don't fiddle with irqchips marked as immutable
>   gpio: Expose the gpiochip_irq_re[ql]res helpers
>   gpio: Add helpers to ease the transition towards immutable irq_chip
>   gpio: tegra186: Make the irqchip immutable
>   gpio: pl061: Make the irqchip immutable
>   pinctrl: apple-gpio: Make the irqchip immutable
>   pinctrl: msmgpio: Make the irqchip immutable
>   pinctrl: amd: Make the irqchip immutable
>   gpio: Update TODO to mention immutable irq_chip structures
>   Documentation: Update the recommended pattern for GPIO irqchips
>
>  Documentation/driver-api/gpio/driver.rst | 175 ++++++++++++++++++-----
>  drivers/gpio/TODO                        |  19 +++
>  drivers/gpio/gpio-pl061.c                |  32 +++--
>  drivers/gpio/gpio-tegra186.c             |  32 +++--
>  drivers/gpio/gpiolib.c                   |  13 +-
>  drivers/pinctrl/pinctrl-amd.c            |  11 +-
>  drivers/pinctrl/pinctrl-apple-gpio.c     |  29 ++--
>  drivers/pinctrl/qcom/pinctrl-msm.c       |  53 ++++---
>  include/linux/gpio/driver.h              |  16 +++
>  include/linux/irq.h                      |   2 +
>  kernel/irq/debugfs.c                     |   1 +
>  11 files changed, 293 insertions(+), 90 deletions(-)
>
> --
> 2.34.1
>

This may be coming too late but for the GPIO part:

Reviewed-by: Bartosz Golaszewski <brgl@bgdev.pl>

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Re: [PATCH v2 00/10] gpiolib: Handle immutable irq_chip structures

[Linus Walleij]

On Tue, Apr 5, 2022 at 3:55 PM Marc Zyngier <maz@kernel.org> wrote:

> Not only this breaks when an irq_chip structure is made const (which
> really should be the default case), but it also forces this structure
> to be copied at nauseam for each instance of the GPIO block, which is
> a waste of memory.
>
> My current approach is to add a new irq_chip flag (IRQCHIP_IMMUTABLE)
> which does what it says on the tin: don't you dare writing to them.
> Gpiolib is further updated not to install its own callbacks, and it
> becomes the responsibility of the driver to call into the gpiolib when
> required. This is similar to what we do for other subsystems such as
> PCI-MSI.
>
> 5 drivers are updated to this new model: M1, QC, Tegra, pl061 and AMD
> (as I actively use them) keeping a single irq_chip structure, marking
> it const, and exposing the new flag.
>
> Nothing breaks, the volume of change is small, the memory usage goes
> down and we have fewer callbacks that can be used as attack vectors.
> What's not to love?
>
> * From v1 [1]:
>   - pl061 and AMD drivers converted
>   - New helpers to keep the changes small
>   - New warning for non-converted drivers
>   - Documentation and TODO updates
>
> [1] https://lore.kernel.org/r/20220223154405.54912-1-maz@kernel.org
>
> Marc Zyngier (10):
>   gpio: Don't fiddle with irqchips marked as immutable
>   gpio: Expose the gpiochip_irq_re[ql]res helpers
>   gpio: Add helpers to ease the transition towards immutable irq_chip
>   gpio: tegra186: Make the irqchip immutable
>   gpio: pl061: Make the irqchip immutable
>   pinctrl: apple-gpio: Make the irqchip immutable
>   pinctrl: msmgpio: Make the irqchip immutable
>   pinctrl: amd: Make the irqchip immutable
>   gpio: Update TODO to mention immutable irq_chip structures
>   Documentation: Update the recommended pattern for GPIO irqchips

Acked-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij

Re: [PATCH v2 00/10] gpiolib: Handle immutable irq_chip structures

[Linus Walleij]

On Tue, Apr 5, 2022 at 3:55 PM Marc Zyngier <maz@kernel.org> wrote:

> Not only this breaks when an irq_chip structure is made const (which
> really should be the default case), but it also forces this structure
> to be copied at nauseam for each instance of the GPIO block, which is
> a waste of memory.
>
> My current approach is to add a new irq_chip flag (IRQCHIP_IMMUTABLE)
> which does what it says on the tin: don't you dare writing to them.
> Gpiolib is further updated not to install its own callbacks, and it
> becomes the responsibility of the driver to call into the gpiolib when
> required. This is similar to what we do for other subsystems such as
> PCI-MSI.
>
> 5 drivers are updated to this new model: M1, QC, Tegra, pl061 and AMD
> (as I actively use them) keeping a single irq_chip structure, marking
> it const, and exposing the new flag.
>
> Nothing breaks, the volume of change is small, the memory usage goes
> down and we have fewer callbacks that can be used as attack vectors.
> What's not to love?
>
> * From v1 [1]:
>   - pl061 and AMD drivers converted
>   - New helpers to keep the changes small
>   - New warning for non-converted drivers
>   - Documentation and TODO updates
>
> [1] https://lore.kernel.org/r/20220223154405.54912-1-maz@kernel.org
>
> Marc Zyngier (10):
>   gpio: Don't fiddle with irqchips marked as immutable
>   gpio: Expose the gpiochip_irq_re[ql]res helpers
>   gpio: Add helpers to ease the transition towards immutable irq_chip
>   gpio: tegra186: Make the irqchip immutable
>   gpio: pl061: Make the irqchip immutable
>   pinctrl: apple-gpio: Make the irqchip immutable
>   pinctrl: msmgpio: Make the irqchip immutable
>   pinctrl: amd: Make the irqchip immutable
>   gpio: Update TODO to mention immutable irq_chip structures
>   Documentation: Update the recommended pattern for GPIO irqchips

Acked-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij

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