[PATCH v2 0/3] simulated interrupts

[PATCH v2 0/3] simulated interrupts

[Bartosz Golaszewski]

Some frameworks (e.g. iio, gpiolib) use irq_work to implement simulated
interrupts that can be 'fired' from process context when needed and
requested just like normal interrupts. This is useful for testing and
development purposes.

Currently this code is reimplemented by every user. This series
proposes to add a new set of functions that can be used by drivers
that want to simulate interrupts without having to duplicate any
boilerplate code.

The first patch adds a simple irq simulator framework. The second
extends it with resource management. The third uses the new
functionality in the gpio-mockup testing driver.

NOTE: The next candidate for using this API would be iio-dummy-evgen.

v1 -> v2:
- added a call to irq_work_sync in irq_sim_fini()

Bartosz Golaszewski (3):
  irq/irq_sim: add a simple interrupt simulator framework
  irq/irq_sim: add a devres variant of irq_sim_init()
  gpio: mockup: use irq_sim

 Documentation/driver-model/devres.txt |   1 +
 drivers/gpio/Kconfig                  |   2 +-
 drivers/gpio/gpio-mockup.c            |  77 ++--------------
 include/linux/irq_sim.h               |  41 +++++++++
 init/Kconfig                          |   4 +
 kernel/Makefile                       |   1 +
 kernel/irq_sim.c                      | 162 ++++++++++++++++++++++++++++++++++
 7 files changed, 217 insertions(+), 71 deletions(-)
 create mode 100644 include/linux/irq_sim.h
 create mode 100644 kernel/irq_sim.c

-- 
2.13.2

[PATCH v2 1/3] irq/irq_sim: add a simple interrupt simulator framework

[Bartosz Golaszewski]

Implement a simple, irq_work-based framework for simulating
interrupts. Currently the API exposes routines for initializing and
deinitializing the simulator object, enqueueing the interrupts and
retrieving the allocated interrupt numbers based on the offset of the
dummy interrupt in the simulator struct.

Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
---
 include/linux/irq_sim.h |  37 +++++++++++++++
 init/Kconfig            |   4 ++
 kernel/Makefile         |   1 +
 kernel/irq_sim.c        | 119 ++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 161 insertions(+)
 create mode 100644 include/linux/irq_sim.h
 create mode 100644 kernel/irq_sim.c

diff --git a/include/linux/irq_sim.h b/include/linux/irq_sim.h
new file mode 100644
index 000000000000..0c1abf0e3244
--- /dev/null
+++ b/include/linux/irq_sim.h
@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2017 Bartosz Golaszewski <brgl@bgdev.pl>
+ *
+ * Provides a framework for allocating simulated interrupts which can be
+ * requested like normal irqs and enqueued from process context.
+ */
+
+#ifndef _LINUX_IRQ_SIM_H
+#define _LINUX_IRQ_SIM_H
+
+#include <linux/irq_work.h>
+
+struct irq_sim_work_ctx {
+	struct irq_work work;
+	int irq;
+};
+
+struct irq_sim_irq_ctx {
+	int irqnum;
+	bool enabled;
+};
+
+struct irq_sim {
+	struct irq_sim_work_ctx work_ctx;
+	int irq_base;
+	unsigned int irq_count;
+	struct irq_sim_irq_ctx *irqs;
+};
+
+int irq_sim_init(struct irq_sim *sim, unsigned int num_irqs);
+void irq_sim_fini(struct irq_sim *sim);
+
+void irq_sim_fire(struct irq_sim *sim, unsigned int offset);
+
+int irq_sim_irqnum(struct irq_sim *sim, unsigned int offset);
+
+#endif /* _LINUX_IRQ_SIM_H */
diff --git a/init/Kconfig b/init/Kconfig
index 8514b25db21c..220456599c3f 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -23,6 +23,10 @@ config CONSTRUCTORS
 config IRQ_WORK
 	bool
 
+config IRQ_SIM
+	bool
+	select IRQ_WORK
+
 config BUILDTIME_EXTABLE_SORT
 	bool
 
diff --git a/kernel/Makefile b/kernel/Makefile
index 4cb8e8b23c6e..4472567c5835 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -97,6 +97,7 @@ obj-$(CONFIG_TRACE_CLOCK) += trace/
 obj-$(CONFIG_RING_BUFFER) += trace/
 obj-$(CONFIG_TRACEPOINTS) += trace/
 obj-$(CONFIG_IRQ_WORK) += irq_work.o
+obj-$(CONFIG_IRQ_SIM) += irq_sim.o
 obj-$(CONFIG_CPU_PM) += cpu_pm.o
 obj-$(CONFIG_BPF) += bpf/
 
diff --git a/kernel/irq_sim.c b/kernel/irq_sim.c
new file mode 100644
index 000000000000..4387e2bee97c
--- /dev/null
+++ b/kernel/irq_sim.c
@@ -0,0 +1,119 @@
+/*
+ * Copyright (C) 2017 Bartosz Golaszewski <brgl@bgdev.pl>
+ *
+ * Provides a framework for allocating simulated interrupts which can be
+ * requested like normal irqs and enqueued from process context.
+ */
+
+#include <linux/irq_sim.h>
+#include <linux/irq.h>
+
+static void irq_sim_irqmask(struct irq_data *data)
+{
+	struct irq_sim_irq_ctx *irq_ctx = irq_data_get_irq_chip_data(data);
+
+	irq_ctx->enabled = false;
+}
+
+static void irq_sim_irqunmask(struct irq_data *data)
+{
+	struct irq_sim_irq_ctx *irq_ctx = irq_data_get_irq_chip_data(data);
+
+	irq_ctx->enabled = true;
+}
+
+static struct irq_chip irq_sim_irqchip = {
+	.name		= "irq_sim",
+	.irq_mask	= irq_sim_irqmask,
+	.irq_unmask	= irq_sim_irqunmask,
+};
+
+static void irq_sim_handle_irq(struct irq_work *work)
+{
+	struct irq_sim_work_ctx *work_ctx;
+
+	work_ctx = container_of(work, struct irq_sim_work_ctx, work);
+	handle_simple_irq(irq_to_desc(work_ctx->irq));
+}
+
+/**
+ * irq_sim_init - Initialize the interrupt simulator: allocate a range of
+ *                dummy interrupts.
+ *
+ * @sim:        The interrupt simulator object to initialize.
+ * @num_irqs:   Number of interrupts to allocate
+ *
+ * Returns 0 on success and a negative error number on failure.
+ */
+int irq_sim_init(struct irq_sim *sim, unsigned int num_irqs)
+{
+	int i;
+
+	sim->irqs = kmalloc_array(num_irqs, sizeof(*sim->irqs), GFP_KERNEL);
+	if (!sim->irqs)
+		return -ENOMEM;
+
+	sim->irq_base = irq_alloc_descs(-1, 0, num_irqs, 0);
+	if (sim->irq_base < 0) {
+		kfree(sim->irqs);
+		return sim->irq_base;
+	}
+
+	for (i = 0; i < num_irqs; i++) {
+		sim->irqs[i].irqnum = sim->irq_base + i;
+		sim->irqs[i].enabled = false;
+		irq_set_chip(sim->irq_base + i, &irq_sim_irqchip);
+		irq_set_chip_data(sim->irq_base + i, &sim->irqs[i]);
+		irq_set_handler(sim->irq_base + i, &handle_simple_irq);
+		irq_modify_status(sim->irq_base + i,
+				  IRQ_NOREQUEST | IRQ_NOAUTOEN, IRQ_NOPROBE);
+	}
+
+	init_irq_work(&sim->work_ctx.work, irq_sim_handle_irq);
+	sim->irq_count = num_irqs;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(irq_sim_init);
+
+/**
+ * irq_sim_fini - Deinitialize the interrupt simulator: free the interrupt
+ *                descriptors and allocated memory.
+ *
+ * @sim:        The interrupt simulator to tear down.
+ */
+void irq_sim_fini(struct irq_sim *sim)
+{
+	irq_work_sync(&sim->work_ctx.work);
+	irq_free_descs(sim->irq_base, sim->irq_count);
+	kfree(sim->irqs);
+}
+EXPORT_SYMBOL_GPL(irq_sim_fini);
+
+/**
+ * irq_sim_fire - Enqueue an interrupt.
+ *
+ * @sim:        The interrupt simulator object.
+ * @offset:     Offset of the simulated interrupt which should be fired.
+ */
+void irq_sim_fire(struct irq_sim *sim, unsigned int offset)
+{
+	if (sim->irqs[offset].enabled) {
+		sim->work_ctx.irq = irq_sim_irqnum(sim, offset);
+		irq_work_queue(&sim->work_ctx.work);
+	}
+}
+EXPORT_SYMBOL_GPL(irq_sim_fire);
+
+/**
+ * irq_sim_irqnum - Get the allocated number of a dummy interrupt.
+ *
+ * @sim:        The interrupt simulator object.
+ * @offset:     Offset of the simulated interrupt for which to retrieve
+ *              the number.
+ */
+int irq_sim_irqnum(struct irq_sim *sim, unsigned int offset)
+{
+	return sim->irqs[offset].irqnum;
+}
+EXPORT_SYMBOL_GPL(irq_sim_irqnum);
-- 
2.13.2

[PATCH v2 2/3] irq/irq_sim: add a devres variant of irq_sim_init()

[Bartosz Golaszewski]

Add a resource managed version of irq_sim_init(). This can be
conveniently used in device drivers.

Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
---
 Documentation/driver-model/devres.txt |  1 +
 include/linux/irq_sim.h               |  4 ++++
 kernel/irq_sim.c                      | 43 +++++++++++++++++++++++++++++++++++
 3 files changed, 48 insertions(+)

diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt
index 30e04f7a690d..69f08c0f23a8 100644
--- a/Documentation/driver-model/devres.txt
+++ b/Documentation/driver-model/devres.txt
@@ -312,6 +312,7 @@ IRQ
   devm_irq_alloc_descs_from()
   devm_irq_alloc_generic_chip()
   devm_irq_setup_generic_chip()
+  devm_irq_sim_init()
 
 LED
   devm_led_classdev_register()
diff --git a/include/linux/irq_sim.h b/include/linux/irq_sim.h
index 0c1abf0e3244..94c4bfc9b7a9 100644
--- a/include/linux/irq_sim.h
+++ b/include/linux/irq_sim.h
@@ -9,6 +9,7 @@
 #define _LINUX_IRQ_SIM_H
 
 #include <linux/irq_work.h>
+#include <linux/device.h>
 
 struct irq_sim_work_ctx {
 	struct irq_work work;
@@ -30,6 +31,9 @@ struct irq_sim {
 int irq_sim_init(struct irq_sim *sim, unsigned int num_irqs);
 void irq_sim_fini(struct irq_sim *sim);
 
+int devm_irq_sim_init(struct device *dev,
+		      struct irq_sim *sim, unsigned int num_irqs);
+
 void irq_sim_fire(struct irq_sim *sim, unsigned int offset);
 
 int irq_sim_irqnum(struct irq_sim *sim, unsigned int offset);
diff --git a/kernel/irq_sim.c b/kernel/irq_sim.c
index 4387e2bee97c..92686c0c7790 100644
--- a/kernel/irq_sim.c
+++ b/kernel/irq_sim.c
@@ -90,6 +90,49 @@ void irq_sim_fini(struct irq_sim *sim)
 }
 EXPORT_SYMBOL_GPL(irq_sim_fini);
 
+struct irq_sim_devres {
+	struct irq_sim *sim;
+};
+
+static void devm_irq_sim_release(struct device *dev, void *res)
+{
+	struct irq_sim_devres *this = res;
+
+	irq_sim_fini(this->sim);
+}
+
+/**
+ * irq_sim_init - Initialize the interrupt simulator for a managed device.
+ *
+ * @dev:        Device to initialize the simulator object for.
+ * @sim:        The interrupt simulator object to initialize.
+ * @num_irqs:   Number of interrupts to allocate
+ *
+ * Returns 0 on success and a negative error number on failure.
+ */
+int devm_irq_sim_init(struct device *dev,
+		      struct irq_sim *sim, unsigned int num_irqs)
+{
+	struct irq_sim_devres *dr;
+	int rv;
+
+	dr = devres_alloc(devm_irq_sim_release, sizeof(*dr), GFP_KERNEL);
+	if (!dr)
+		return -ENOMEM;
+
+	rv = irq_sim_init(sim, num_irqs);
+	if (rv) {
+		devres_free(dr);
+		return rv;
+	}
+
+	dr->sim = sim;
+	devres_add(dev, dr);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(devm_irq_sim_init);
+
 /**
  * irq_sim_fire - Enqueue an interrupt.
  *
-- 
2.13.2

[PATCH v2 3/3] gpio: mockup: use irq_sim

[Bartosz Golaszewski]

Shrink the driver by removing the code dealing with dummy interrupts
and replacing it with calls to the irq_sim API.

Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
---
 drivers/gpio/Kconfig       |  2 +-
 drivers/gpio/gpio-mockup.c | 77 +++++-----------------------------------------
 2 files changed, 8 insertions(+), 71 deletions(-)

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index f235eae04c16..e2264fb31f87 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -311,7 +311,7 @@ config GPIO_MOCKUP
 	depends on GPIOLIB && SYSFS
 	select GPIO_SYSFS
 	select GPIOLIB_IRQCHIP
-	select IRQ_WORK
+	select IRQ_SIM
 	help
 	  This enables GPIO Testing driver, which provides a way to test GPIO
 	  subsystem through sysfs(or char device) and debugfs. GPIO_SYSFS
diff --git a/drivers/gpio/gpio-mockup.c b/drivers/gpio/gpio-mockup.c
index a6565e128f9e..6db7163e6d98 100644
--- a/drivers/gpio/gpio-mockup.c
+++ b/drivers/gpio/gpio-mockup.c
@@ -20,7 +20,7 @@
 #include <linux/slab.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
-#include <linux/irq_work.h>
+#include <linux/irq_sim.h>
 #include <linux/debugfs.h>
 #include <linux/uaccess.h>
 
@@ -47,18 +47,12 @@ enum {
 struct gpio_mockup_line_status {
 	int dir;
 	bool value;
-	bool irq_enabled;
-};
-
-struct gpio_mockup_irq_context {
-	struct irq_work work;
-	int irq;
 };
 
 struct gpio_mockup_chip {
 	struct gpio_chip gc;
 	struct gpio_mockup_line_status *lines;
-	struct gpio_mockup_irq_context irq_ctx;
+	struct irq_sim irqsim;
 	struct dentry *dbg_dir;
 };
 
@@ -144,65 +138,11 @@ static int gpio_mockup_name_lines(struct device *dev,
 	return 0;
 }
 
-static int gpio_mockup_to_irq(struct gpio_chip *chip, unsigned int offset)
-{
-	return chip->irq_base + offset;
-}
-
-static void gpio_mockup_irqmask(struct irq_data *data)
+static int gpio_mockup_to_irq(struct gpio_chip *gc, unsigned int offset)
 {
-	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
 	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
 
-	chip->lines[data->irq - gc->irq_base].irq_enabled = false;
-}
-
-static void gpio_mockup_irqunmask(struct irq_data *data)
-{
-	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
-	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
-
-	chip->lines[data->irq - gc->irq_base].irq_enabled = true;
-}
-
-static struct irq_chip gpio_mockup_irqchip = {
-	.name		= GPIO_MOCKUP_NAME,
-	.irq_mask	= gpio_mockup_irqmask,
-	.irq_unmask	= gpio_mockup_irqunmask,
-};
-
-static void gpio_mockup_handle_irq(struct irq_work *work)
-{
-	struct gpio_mockup_irq_context *irq_ctx;
-
-	irq_ctx = container_of(work, struct gpio_mockup_irq_context, work);
-	handle_simple_irq(irq_to_desc(irq_ctx->irq));
-}
-
-static int gpio_mockup_irqchip_setup(struct device *dev,
-				     struct gpio_mockup_chip *chip)
-{
-	struct gpio_chip *gc = &chip->gc;
-	int irq_base, i;
-
-	irq_base = devm_irq_alloc_descs(dev, -1, 0, gc->ngpio, 0);
-	if (irq_base < 0)
-		return irq_base;
-
-	gc->irq_base = irq_base;
-	gc->irqchip = &gpio_mockup_irqchip;
-
-	for (i = 0; i < gc->ngpio; i++) {
-		irq_set_chip(irq_base + i, gc->irqchip);
-		irq_set_chip_data(irq_base + i, gc);
-		irq_set_handler(irq_base + i, &handle_simple_irq);
-		irq_modify_status(irq_base + i,
-				  IRQ_NOREQUEST | IRQ_NOAUTOEN, IRQ_NOPROBE);
-	}
-
-	init_irq_work(&chip->irq_ctx.work, gpio_mockup_handle_irq);
-
-	return 0;
+	return irq_sim_irqnum(&chip->irqsim, offset);
 }
 
 static ssize_t gpio_mockup_event_write(struct file *file,
@@ -228,11 +168,8 @@ static ssize_t gpio_mockup_event_write(struct file *file,
 	chip = priv->chip;
 	gc = &chip->gc;
 
-	if (chip->lines[priv->offset].irq_enabled) {
-		gpiod_set_value_cansleep(desc, val);
-		priv->chip->irq_ctx.irq = gc->irq_base + priv->offset;
-		irq_work_queue(&priv->chip->irq_ctx.work);
-	}
+	gpiod_set_value_cansleep(desc, val);
+	irq_sim_fire(&chip->irqsim, priv->offset);
 
 	return size;
 }
@@ -319,7 +256,7 @@ static int gpio_mockup_add(struct device *dev,
 			return ret;
 	}
 
-	ret = gpio_mockup_irqchip_setup(dev, chip);
+	ret = devm_irq_sim_init(dev, &chip->irqsim, gc->ngpio);
 	if (ret)
 		return ret;
 
-- 
2.13.2

Re: [PATCH v2 1/3] irq/irq_sim: add a simple interrupt simulator framework

[Jonathan Cameron]

On Tue,  1 Aug 2017 16:50:26 +0200
Bartosz Golaszewski <brgl@bgdev.pl> wrote:

> Implement a simple, irq_work-based framework for simulating
> interrupts. Currently the API exposes routines for initializing and
> deinitializing the simulator object, enqueueing the interrupts and
> retrieving the allocated interrupt numbers based on the offset of the
> dummy interrupt in the simulator struct.
> 
> Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Looks good to me.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Only tiny thing is the lack of a specified license for the code...
+ checkpatch is warning about wrong file mode...
#105: 
new file mode 100644

Though I have no idea why...

+ behind a certain firewall so no Google available...
> ---
>  include/linux/irq_sim.h |  37 +++++++++++++++
>  init/Kconfig            |   4 ++
>  kernel/Makefile         |   1 +
>  kernel/irq_sim.c        | 119 ++++++++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 161 insertions(+)
>  create mode 100644 include/linux/irq_sim.h
>  create mode 100644 kernel/irq_sim.c
> 
> diff --git a/include/linux/irq_sim.h b/include/linux/irq_sim.h
> new file mode 100644
> index 000000000000..0c1abf0e3244
> --- /dev/null
> +++ b/include/linux/irq_sim.h
> @@ -0,0 +1,37 @@
> +/*
> + * Copyright (C) 2017 Bartosz Golaszewski <brgl@bgdev.pl>
> + *
> + * Provides a framework for allocating simulated interrupts which can be
> + * requested like normal irqs and enqueued from process context.
> + */
> +
> +#ifndef _LINUX_IRQ_SIM_H
> +#define _LINUX_IRQ_SIM_H
> +
> +#include <linux/irq_work.h>
> +
> +struct irq_sim_work_ctx {
> +	struct irq_work work;
> +	int irq;
> +};
> +
> +struct irq_sim_irq_ctx {
> +	int irqnum;
> +	bool enabled;
> +};
> +
> +struct irq_sim {
> +	struct irq_sim_work_ctx work_ctx;
> +	int irq_base;
> +	unsigned int irq_count;
> +	struct irq_sim_irq_ctx *irqs;
> +};
> +
> +int irq_sim_init(struct irq_sim *sim, unsigned int num_irqs);
> +void irq_sim_fini(struct irq_sim *sim);
> +
> +void irq_sim_fire(struct irq_sim *sim, unsigned int offset);
> +
> +int irq_sim_irqnum(struct irq_sim *sim, unsigned int offset);
> +
> +#endif /* _LINUX_IRQ_SIM_H */
> diff --git a/init/Kconfig b/init/Kconfig
> index 8514b25db21c..220456599c3f 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -23,6 +23,10 @@ config CONSTRUCTORS
>  config IRQ_WORK
>  	bool
>  
> +config IRQ_SIM
> +	bool
You could make this tristate, but then the handling of the
users would get complex so perhaps given it's so small boolean
is the way to go.
> +	select IRQ_WORK
> +
>  config BUILDTIME_EXTABLE_SORT
>  	bool
>  
> diff --git a/kernel/Makefile b/kernel/Makefile
> index 4cb8e8b23c6e..4472567c5835 100644
> --- a/kernel/Makefile
> +++ b/kernel/Makefile
> @@ -97,6 +97,7 @@ obj-$(CONFIG_TRACE_CLOCK) += trace/
>  obj-$(CONFIG_RING_BUFFER) += trace/
>  obj-$(CONFIG_TRACEPOINTS) += trace/
>  obj-$(CONFIG_IRQ_WORK) += irq_work.o
> +obj-$(CONFIG_IRQ_SIM) += irq_sim.o
>  obj-$(CONFIG_CPU_PM) += cpu_pm.o
>  obj-$(CONFIG_BPF) += bpf/
>  
> diff --git a/kernel/irq_sim.c b/kernel/irq_sim.c
> new file mode 100644
> index 000000000000..4387e2bee97c
> --- /dev/null
> +++ b/kernel/irq_sim.c
> @@ -0,0 +1,119 @@
> +/*
> + * Copyright (C) 2017 Bartosz Golaszewski <brgl@bgdev.pl>
> + *
> + * Provides a framework for allocating simulated interrupts which can be
> + * requested like normal irqs and enqueued from process context.
> + */
> +
> +#include <linux/irq_sim.h>
> +#include <linux/irq.h>
> +
> +static void irq_sim_irqmask(struct irq_data *data)
> +{
> +	struct irq_sim_irq_ctx *irq_ctx = irq_data_get_irq_chip_data(data);
> +
> +	irq_ctx->enabled = false;
> +}
> +
> +static void irq_sim_irqunmask(struct irq_data *data)
> +{
> +	struct irq_sim_irq_ctx *irq_ctx = irq_data_get_irq_chip_data(data);
> +
> +	irq_ctx->enabled = true;
> +}
> +
> +static struct irq_chip irq_sim_irqchip = {
> +	.name		= "irq_sim",
> +	.irq_mask	= irq_sim_irqmask,
> +	.irq_unmask	= irq_sim_irqunmask,
> +};
> +
> +static void irq_sim_handle_irq(struct irq_work *work)
> +{
> +	struct irq_sim_work_ctx *work_ctx;
> +
> +	work_ctx = container_of(work, struct irq_sim_work_ctx, work);
> +	handle_simple_irq(irq_to_desc(work_ctx->irq));
> +}
> +
> +/**
> + * irq_sim_init - Initialize the interrupt simulator: allocate a range of
> + *                dummy interrupts.
> + *
> + * @sim:        The interrupt simulator object to initialize.
> + * @num_irqs:   Number of interrupts to allocate
> + *
> + * Returns 0 on success and a negative error number on failure.
> + */
> +int irq_sim_init(struct irq_sim *sim, unsigned int num_irqs)
> +{
> +	int i;
> +
> +	sim->irqs = kmalloc_array(num_irqs, sizeof(*sim->irqs), GFP_KERNEL);
> +	if (!sim->irqs)
> +		return -ENOMEM;
> +
> +	sim->irq_base = irq_alloc_descs(-1, 0, num_irqs, 0);
> +	if (sim->irq_base < 0) {
> +		kfree(sim->irqs);
> +		return sim->irq_base;
> +	}
> +
> +	for (i = 0; i < num_irqs; i++) {
> +		sim->irqs[i].irqnum = sim->irq_base + i;
> +		sim->irqs[i].enabled = false;
> +		irq_set_chip(sim->irq_base + i, &irq_sim_irqchip);
> +		irq_set_chip_data(sim->irq_base + i, &sim->irqs[i]);
> +		irq_set_handler(sim->irq_base + i, &handle_simple_irq);
> +		irq_modify_status(sim->irq_base + i,
> +				  IRQ_NOREQUEST | IRQ_NOAUTOEN, IRQ_NOPROBE);
> +	}
> +
> +	init_irq_work(&sim->work_ctx.work, irq_sim_handle_irq);
> +	sim->irq_count = num_irqs;
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(irq_sim_init);
> +
> +/**
> + * irq_sim_fini - Deinitialize the interrupt simulator: free the interrupt
> + *                descriptors and allocated memory.
> + *
> + * @sim:        The interrupt simulator to tear down.
> + */
> +void irq_sim_fini(struct irq_sim *sim)
> +{
> +	irq_work_sync(&sim->work_ctx.work);
> +	irq_free_descs(sim->irq_base, sim->irq_count);
> +	kfree(sim->irqs);
> +}
> +EXPORT_SYMBOL_GPL(irq_sim_fini);
> +
> +/**
> + * irq_sim_fire - Enqueue an interrupt.
> + *
> + * @sim:        The interrupt simulator object.
> + * @offset:     Offset of the simulated interrupt which should be fired.
> + */
> +void irq_sim_fire(struct irq_sim *sim, unsigned int offset)
> +{
> +	if (sim->irqs[offset].enabled) {
> +		sim->work_ctx.irq = irq_sim_irqnum(sim, offset);
> +		irq_work_queue(&sim->work_ctx.work);
> +	}
> +}
> +EXPORT_SYMBOL_GPL(irq_sim_fire);
> +
> +/**
> + * irq_sim_irqnum - Get the allocated number of a dummy interrupt.
> + *
> + * @sim:        The interrupt simulator object.
> + * @offset:     Offset of the simulated interrupt for which to retrieve
> + *              the number.
> + */
> +int irq_sim_irqnum(struct irq_sim *sim, unsigned int offset)
> +{
> +	return sim->irqs[offset].irqnum;
> +}
> +EXPORT_SYMBOL_GPL(irq_sim_irqnum);

Re: [PATCH v2 3/3] gpio: mockup: use irq_sim

[Jonathan Cameron]

On Tue,  1 Aug 2017 16:50:28 +0200
Bartosz Golaszewski <brgl@bgdev.pl> wrote:

> Shrink the driver by removing the code dealing with dummy interrupts
> and replacing it with calls to the irq_sim API.
> 
> Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Looks straight forward to me.

Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> ---
>  drivers/gpio/Kconfig       |  2 +-
>  drivers/gpio/gpio-mockup.c | 77 +++++-----------------------------------------
>  2 files changed, 8 insertions(+), 71 deletions(-)
> 
> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> index f235eae04c16..e2264fb31f87 100644
> --- a/drivers/gpio/Kconfig
> +++ b/drivers/gpio/Kconfig
> @@ -311,7 +311,7 @@ config GPIO_MOCKUP
>  	depends on GPIOLIB && SYSFS
>  	select GPIO_SYSFS
>  	select GPIOLIB_IRQCHIP
> -	select IRQ_WORK
> +	select IRQ_SIM
>  	help
>  	  This enables GPIO Testing driver, which provides a way to test GPIO
>  	  subsystem through sysfs(or char device) and debugfs. GPIO_SYSFS
> diff --git a/drivers/gpio/gpio-mockup.c b/drivers/gpio/gpio-mockup.c
> index a6565e128f9e..6db7163e6d98 100644
> --- a/drivers/gpio/gpio-mockup.c
> +++ b/drivers/gpio/gpio-mockup.c
> @@ -20,7 +20,7 @@
>  #include <linux/slab.h>
>  #include <linux/interrupt.h>
>  #include <linux/irq.h>
> -#include <linux/irq_work.h>
> +#include <linux/irq_sim.h>
>  #include <linux/debugfs.h>
>  #include <linux/uaccess.h>
>  
> @@ -47,18 +47,12 @@ enum {
>  struct gpio_mockup_line_status {
>  	int dir;
>  	bool value;
> -	bool irq_enabled;
> -};
> -
> -struct gpio_mockup_irq_context {
> -	struct irq_work work;
> -	int irq;
>  };
>  
>  struct gpio_mockup_chip {
>  	struct gpio_chip gc;
>  	struct gpio_mockup_line_status *lines;
> -	struct gpio_mockup_irq_context irq_ctx;
> +	struct irq_sim irqsim;
>  	struct dentry *dbg_dir;
>  };
>  
> @@ -144,65 +138,11 @@ static int gpio_mockup_name_lines(struct device *dev,
>  	return 0;
>  }
>  
> -static int gpio_mockup_to_irq(struct gpio_chip *chip, unsigned int offset)
> -{
> -	return chip->irq_base + offset;
> -}
> -
> -static void gpio_mockup_irqmask(struct irq_data *data)
> +static int gpio_mockup_to_irq(struct gpio_chip *gc, unsigned int offset)
>  {
> -	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
>  	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
>  
> -	chip->lines[data->irq - gc->irq_base].irq_enabled = false;
> -}
> -
> -static void gpio_mockup_irqunmask(struct irq_data *data)
> -{
> -	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
> -	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
> -
> -	chip->lines[data->irq - gc->irq_base].irq_enabled = true;
> -}
> -
> -static struct irq_chip gpio_mockup_irqchip = {
> -	.name		= GPIO_MOCKUP_NAME,
> -	.irq_mask	= gpio_mockup_irqmask,
> -	.irq_unmask	= gpio_mockup_irqunmask,
> -};
> -
> -static void gpio_mockup_handle_irq(struct irq_work *work)
> -{
> -	struct gpio_mockup_irq_context *irq_ctx;
> -
> -	irq_ctx = container_of(work, struct gpio_mockup_irq_context, work);
> -	handle_simple_irq(irq_to_desc(irq_ctx->irq));
> -}
> -
> -static int gpio_mockup_irqchip_setup(struct device *dev,
> -				     struct gpio_mockup_chip *chip)
> -{
> -	struct gpio_chip *gc = &chip->gc;
> -	int irq_base, i;
> -
> -	irq_base = devm_irq_alloc_descs(dev, -1, 0, gc->ngpio, 0);
> -	if (irq_base < 0)
> -		return irq_base;
> -
> -	gc->irq_base = irq_base;
> -	gc->irqchip = &gpio_mockup_irqchip;
> -
> -	for (i = 0; i < gc->ngpio; i++) {
> -		irq_set_chip(irq_base + i, gc->irqchip);
> -		irq_set_chip_data(irq_base + i, gc);
> -		irq_set_handler(irq_base + i, &handle_simple_irq);
> -		irq_modify_status(irq_base + i,
> -				  IRQ_NOREQUEST | IRQ_NOAUTOEN, IRQ_NOPROBE);
> -	}
> -
> -	init_irq_work(&chip->irq_ctx.work, gpio_mockup_handle_irq);
> -
> -	return 0;
> +	return irq_sim_irqnum(&chip->irqsim, offset);
>  }
>  
>  static ssize_t gpio_mockup_event_write(struct file *file,
> @@ -228,11 +168,8 @@ static ssize_t gpio_mockup_event_write(struct file *file,
>  	chip = priv->chip;
>  	gc = &chip->gc;
>  
> -	if (chip->lines[priv->offset].irq_enabled) {
> -		gpiod_set_value_cansleep(desc, val);
> -		priv->chip->irq_ctx.irq = gc->irq_base + priv->offset;
> -		irq_work_queue(&priv->chip->irq_ctx.work);
> -	}
> +	gpiod_set_value_cansleep(desc, val);
> +	irq_sim_fire(&chip->irqsim, priv->offset);
>  
>  	return size;
>  }
> @@ -319,7 +256,7 @@ static int gpio_mockup_add(struct device *dev,
>  			return ret;
>  	}
>  
> -	ret = gpio_mockup_irqchip_setup(dev, chip);
> +	ret = devm_irq_sim_init(dev, &chip->irqsim, gc->ngpio);
>  	if (ret)
>  		return ret;
>  

Re: [PATCH v2 2/3] irq/irq_sim: add a devres variant of irq_sim_init()

[Jonathan Cameron]

On Tue,  1 Aug 2017 16:50:27 +0200
Bartosz Golaszewski <brgl@bgdev.pl> wrote:

> Add a resource managed version of irq_sim_init(). This can be
> conveniently used in device drivers.
> 
> Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Looks pretty standard to me.

Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> ---
>  Documentation/driver-model/devres.txt |  1 +
>  include/linux/irq_sim.h               |  4 ++++
>  kernel/irq_sim.c                      | 43 +++++++++++++++++++++++++++++++++++
>  3 files changed, 48 insertions(+)
> 
> diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt
> index 30e04f7a690d..69f08c0f23a8 100644
> --- a/Documentation/driver-model/devres.txt
> +++ b/Documentation/driver-model/devres.txt
> @@ -312,6 +312,7 @@ IRQ
>    devm_irq_alloc_descs_from()
>    devm_irq_alloc_generic_chip()
>    devm_irq_setup_generic_chip()
> +  devm_irq_sim_init()
>  
>  LED
>    devm_led_classdev_register()
> diff --git a/include/linux/irq_sim.h b/include/linux/irq_sim.h
> index 0c1abf0e3244..94c4bfc9b7a9 100644
> --- a/include/linux/irq_sim.h
> +++ b/include/linux/irq_sim.h
> @@ -9,6 +9,7 @@
>  #define _LINUX_IRQ_SIM_H
>  
>  #include <linux/irq_work.h>
> +#include <linux/device.h>
>  
>  struct irq_sim_work_ctx {
>  	struct irq_work work;
> @@ -30,6 +31,9 @@ struct irq_sim {
>  int irq_sim_init(struct irq_sim *sim, unsigned int num_irqs);
>  void irq_sim_fini(struct irq_sim *sim);
>  
> +int devm_irq_sim_init(struct device *dev,
> +		      struct irq_sim *sim, unsigned int num_irqs);
> +
>  void irq_sim_fire(struct irq_sim *sim, unsigned int offset);
>  
>  int irq_sim_irqnum(struct irq_sim *sim, unsigned int offset);
> diff --git a/kernel/irq_sim.c b/kernel/irq_sim.c
> index 4387e2bee97c..92686c0c7790 100644
> --- a/kernel/irq_sim.c
> +++ b/kernel/irq_sim.c
> @@ -90,6 +90,49 @@ void irq_sim_fini(struct irq_sim *sim)
>  }
>  EXPORT_SYMBOL_GPL(irq_sim_fini);
>  
> +struct irq_sim_devres {
> +	struct irq_sim *sim;
> +};
> +
> +static void devm_irq_sim_release(struct device *dev, void *res)
> +{
> +	struct irq_sim_devres *this = res;
> +
> +	irq_sim_fini(this->sim);
> +}
> +
> +/**
> + * irq_sim_init - Initialize the interrupt simulator for a managed device.
> + *
> + * @dev:        Device to initialize the simulator object for.
> + * @sim:        The interrupt simulator object to initialize.
> + * @num_irqs:   Number of interrupts to allocate
> + *
> + * Returns 0 on success and a negative error number on failure.
> + */
> +int devm_irq_sim_init(struct device *dev,
> +		      struct irq_sim *sim, unsigned int num_irqs)
> +{
> +	struct irq_sim_devres *dr;
> +	int rv;
> +
> +	dr = devres_alloc(devm_irq_sim_release, sizeof(*dr), GFP_KERNEL);
> +	if (!dr)
> +		return -ENOMEM;
> +
> +	rv = irq_sim_init(sim, num_irqs);
> +	if (rv) {
> +		devres_free(dr);
> +		return rv;
> +	}
> +
> +	dr->sim = sim;
> +	devres_add(dev, dr);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(devm_irq_sim_init);
> +
>  /**
>   * irq_sim_fire - Enqueue an interrupt.
>   *

Re: [PATCH v2 3/3] gpio: mockup: use irq_sim

[Linus Walleij]

On Tue, Aug 1, 2017 at 4:50 PM, Bartosz Golaszewski <brgl@bgdev.pl> wrote:

> Shrink the driver by removing the code dealing with dummy interrupts
> and replacing it with calls to the irq_sim API.
>
> Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>

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

Tglx/Marc: feel free to merge this with the rest into the irqchip tree.

Yours,
Linus Walleij

Re: [PATCH v2 1/3] irq/irq_sim: add a simple interrupt simulator framework

[Bartosz Golaszewski]

2017-08-12 13:43 GMT+02:00 Jonathan Cameron <jic23@kernel.org>:
> On Tue,  1 Aug 2017 16:50:26 +0200
> Bartosz Golaszewski <brgl@bgdev.pl> wrote:
>
>> Implement a simple, irq_work-based framework for simulating
>> interrupts. Currently the API exposes routines for initializing and
>> deinitializing the simulator object, enqueueing the interrupts and
>> retrieving the allocated interrupt numbers based on the offset of the
>> dummy interrupt in the simulator struct.
>>
>> Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
> Looks good to me.
>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
>
> Only tiny thing is the lack of a specified license for the code...

I'll send a v3 with license added.

> + checkpatch is warning about wrong file mode...
> #105:
> new file mode 100644
>
> Though I have no idea why...
>

I think this only says that a file was created with given mode, it's
not a warning. The actual warning is about missing a new entry in
MAINTAINERS.

>> --- a/init/Kconfig
>> +++ b/init/Kconfig
>> @@ -23,6 +23,10 @@ config CONSTRUCTORS
>>  config IRQ_WORK
>>       bool
>>
>> +config IRQ_SIM
>> +     bool
> You could make this tristate, but then the handling of the
> users would get complex so perhaps given it's so small boolean
> is the way to go.
>

Nah, irq_work is built-in to at even greater size. Let's just leave it
like this, especially when only testing modules select it.

Thanks,
Bartosz

Re: [PATCH v2 1/3] irq/irq_sim: add a simple interrupt simulator framework

[Jonathan Cameron]

On 14 August 2017 17:54:22 GMT+08:00, Bartosz Golaszewski <brgl@bgdev.pl> wrote:
>2017-08-12 13:43 GMT+02:00 Jonathan Cameron <jic23@kernel.org>:
>> On Tue,  1 Aug 2017 16:50:26 +0200
>> Bartosz Golaszewski <brgl@bgdev.pl> wrote:
>>
>>> Implement a simple, irq_work-based framework for simulating
>>> interrupts. Currently the API exposes routines for initializing and
>>> deinitializing the simulator object, enqueueing the interrupts and
>>> retrieving the allocated interrupt numbers based on the offset of
>the
>>> dummy interrupt in the simulator struct.
>>>
>>> Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
>> Looks good to me.
>>
>> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
>>
>> Only tiny thing is the lack of a specified license for the code...
>
>I'll send a v3 with license added.
>
>> + checkpatch is warning about wrong file mode...
>> #105:
>> new file mode 100644
>>
>> Though I have no idea why...
>>
>
>I think this only says that a file was created with given mode, it's
>not a warning. The actual warning is about missing a new entry in
>MAINTAINERS.
Doh, how did I miss that!


>
>>> --- a/init/Kconfig
>>> +++ b/init/Kconfig
>>> @@ -23,6 +23,10 @@ config CONSTRUCTORS
>>>  config IRQ_WORK
>>>       bool
>>>
>>> +config IRQ_SIM
>>> +     bool
>> You could make this tristate, but then the handling of the
>> users would get complex so perhaps given it's so small boolean
>> is the way to go.
>>
>
>Nah, irq_work is built-in to at even greater size. Let's just leave it
>like this, especially when only testing modules select it.
>
Fair enough.

>Thanks,
>Bartosz

-- 
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