[PATCH v3 2/2] irq/irq_sim: simplify the API

From: Bartosz Golaszewski
Date: Fri Apr 17 2020 - 04:12:26 EST

From: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>

The interrupt simulator API exposes a lot of custom data structures and
functions and doesn't reuse the interfaces already exposed by the irq
subsystem. This patch tries to address it.

We hide all the simulator-related data structures from users and instead
rely on the well-known irq domain. When creating the interrupt simulator
the user receives a pointer to a newly created irq_domain and can use it
to create mappings for simulated interrupts.

It is also possible to pass a handle to fwnode when creating the simulator
domain and retrieve it using irq_find_matching_fwnode().

The irq_sim_fire() function now only takes the virtual interrupt number
as argument - there's no need anymore to pass it any data structure linked
to the simulator.

We modify the two modules that use the simulator at the same time as
adding these changes in order to reduce the intermediate bloat that would
result when trying to migrate the drivers in separate patches.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
---
drivers/gpio/gpio-mockup.c | 47 ++++--
drivers/iio/dummy/iio_dummy_evgen.c | 32 ++--
include/linux/irq_sim.h | 34 ++---
kernel/irq/Kconfig | 1 +
kernel/irq/irq_sim.c | 225 +++++++++++++++++-----------
5 files changed, 202 insertions(+), 137 deletions(-)

diff --git a/drivers/gpio/gpio-mockup.c b/drivers/gpio/gpio-mockup.c
index 3eb94f3740d1..941a967296c4 100644
--- a/drivers/gpio/gpio-mockup.c
+++ b/drivers/gpio/gpio-mockup.c
@@ -14,6 +14,7 @@
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/irq_sim.h>
+#include <linux/irqdomain.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/property.h>
@@ -48,7 +49,7 @@ struct gpio_mockup_line_status {
struct gpio_mockup_chip {
struct gpio_chip gc;
struct gpio_mockup_line_status *lines;
- struct irq_sim irqsim;
+ struct irq_domain *irq_sim_domain;
struct dentry *dbg_dir;
struct mutex lock;
};
@@ -144,14 +145,12 @@ static void gpio_mockup_set_multiple(struct gpio_chip *gc,
static int gpio_mockup_apply_pull(struct gpio_mockup_chip *chip,
unsigned int offset, int value)
{
+ int curr, irq, irq_type, ret = 0;
struct gpio_desc *desc;
struct gpio_chip *gc;
- struct irq_sim *sim;
- int curr, irq, irq_type;

gc = &chip->gc;
desc = &gc->gpiodev->descs[offset];
- sim = &chip->irqsim;

mutex_lock(&chip->lock);

@@ -161,14 +160,24 @@ static int gpio_mockup_apply_pull(struct gpio_mockup_chip *chip,
if (curr == value)
goto out;

- irq = irq_sim_irqnum(sim, offset);
+ irq = irq_find_mapping(chip->irq_sim_domain, offset);
+ if (!irq)
+ /*
+ * This is fine - it just means, nobody is listening
+ * for interrupts on this line, otherwise
+ * irq_create_mapping() would have been called from
+ * the to_irq() callback.
+ */
+ goto set_value;
+
irq_type = irq_get_trigger_type(irq);

if ((value == 1 && (irq_type & IRQ_TYPE_EDGE_RISING)) ||
(value == 0 && (irq_type & IRQ_TYPE_EDGE_FALLING)))
- irq_sim_fire(sim, offset);
+ irq_sim_fire(irq);
}

+set_value:
/* Change the value unless we're actively driving the line. */
if (!test_bit(FLAG_REQUESTED, &desc->flags) ||
!test_bit(FLAG_IS_OUT, &desc->flags))
@@ -177,7 +186,7 @@ static int gpio_mockup_apply_pull(struct gpio_mockup_chip *chip,
out:
chip->lines[offset].pull = value;
mutex_unlock(&chip->lock);
- return 0;
+ return ret;
}

static int gpio_mockup_set_config(struct gpio_chip *gc,
@@ -236,7 +245,7 @@ static int gpio_mockup_to_irq(struct gpio_chip *gc, unsigned int offset)
{
struct gpio_mockup_chip *chip = gpiochip_get_data(gc);

- return irq_sim_irqnum(&chip->irqsim, offset);
+ return irq_create_mapping(chip->irq_sim_domain, offset);
}

static void gpio_mockup_free(struct gpio_chip *gc, unsigned int offset)
@@ -389,6 +398,19 @@ static int gpio_mockup_name_lines(struct device *dev,
return 0;
}

+static void gpio_mockup_dispose_mappings(void *data)
+{
+ struct gpio_mockup_chip *chip = data;
+ struct gpio_chip *gc = &chip->gc;
+ int i, irq;
+
+ for (i = 0; i < gc->ngpio; i++) {
+ irq = irq_find_mapping(chip->irq_sim_domain, i);
+ if (irq)
+ irq_dispose_mapping(irq);
+ }
+}
+
static int gpio_mockup_probe(struct platform_device *pdev)
{
struct gpio_mockup_chip *chip;
@@ -456,8 +478,13 @@ static int gpio_mockup_probe(struct platform_device *pdev)
return rv;
}

- rv = devm_irq_sim_init(dev, &chip->irqsim, gc->ngpio);
- if (rv < 0)
+ chip->irq_sim_domain = devm_irq_domain_create_sim(dev, NULL,
+ gc->ngpio);
+ if (IS_ERR(chip->irq_sim_domain))
+ return PTR_ERR(chip->irq_sim_domain);
+
+ rv = devm_add_action_or_reset(dev, gpio_mockup_dispose_mappings, chip);
+ if (rv)
return rv;

rv = devm_gpiochip_add_data(dev, &chip->gc, chip);
diff --git a/drivers/iio/dummy/iio_dummy_evgen.c b/drivers/iio/dummy/iio_dummy_evgen.c
index a6edf30567aa..31c9e012abeb 100644
--- a/drivers/iio/dummy/iio_dummy_evgen.c
+++ b/drivers/iio/dummy/iio_dummy_evgen.c
@@ -37,8 +37,7 @@ struct iio_dummy_eventgen {
struct iio_dummy_regs regs[IIO_EVENTGEN_NO];
struct mutex lock;
bool inuse[IIO_EVENTGEN_NO];
- struct irq_sim irq_sim;
- int base;
+ struct irq_domain *irq_sim_domain;
};

/* We can only ever have one instance of this 'device' */
@@ -46,19 +45,17 @@ static struct iio_dummy_eventgen *iio_evgen;

static int iio_dummy_evgen_create(void)
{
- int ret;
-
iio_evgen = kzalloc(sizeof(*iio_evgen), GFP_KERNEL);
if (!iio_evgen)
return -ENOMEM;

- ret = irq_sim_init(&iio_evgen->irq_sim, IIO_EVENTGEN_NO);
- if (ret < 0) {
+ iio_evgen->irq_sim_domain = irq_domain_create_sim(NULL,
+ IIO_EVENTGEN_NO);
+ if (IS_ERR(iio_evgen->irq_sim_domain)) {
kfree(iio_evgen);
- return ret;
+ return PTR_ERR(iio_evgen->irq_sim_domain);
}

- iio_evgen->base = irq_sim_irqnum(&iio_evgen->irq_sim, 0);
mutex_init(&iio_evgen->lock);

return 0;
@@ -80,7 +77,7 @@ int iio_dummy_evgen_get_irq(void)
mutex_lock(&iio_evgen->lock);
for (i = 0; i < IIO_EVENTGEN_NO; i++) {
if (!iio_evgen->inuse[i]) {
- ret = irq_sim_irqnum(&iio_evgen->irq_sim, i);
+ ret = irq_create_mapping(iio_evgen->irq_sim_domain, i);
iio_evgen->inuse[i] = true;
break;
}
@@ -101,21 +98,27 @@ EXPORT_SYMBOL_GPL(iio_dummy_evgen_get_irq);
*/
void iio_dummy_evgen_release_irq(int irq)
{
+ struct irq_data *irqd = irq_get_irq_data(irq);
+
mutex_lock(&iio_evgen->lock);
- iio_evgen->inuse[irq - iio_evgen->base] = false;
+ iio_evgen->inuse[irqd_to_hwirq(irqd)] = false;
+ irq_dispose_mapping(irq);
mutex_unlock(&iio_evgen->lock);
}
EXPORT_SYMBOL_GPL(iio_dummy_evgen_release_irq);

struct iio_dummy_regs *iio_dummy_evgen_get_regs(int irq)
{
- return &iio_evgen->regs[irq - iio_evgen->base];
+ struct irq_data *irqd = irq_get_irq_data(irq);
+
+ return &iio_evgen->regs[irqd_to_hwirq(irqd)];
+
}
EXPORT_SYMBOL_GPL(iio_dummy_evgen_get_regs);

static void iio_dummy_evgen_free(void)
{
- irq_sim_fini(&iio_evgen->irq_sim);
+ irq_domain_remove_sim(iio_evgen->irq_sim_domain);
kfree(iio_evgen);
}

@@ -131,7 +134,7 @@ static ssize_t iio_evgen_poke(struct device *dev,
{
struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
unsigned long event;
- int ret;
+ int ret, irq;

ret = kstrtoul(buf, 10, &event);
if (ret)
@@ -140,7 +143,8 @@ static ssize_t iio_evgen_poke(struct device *dev,
iio_evgen->regs[this_attr->address].reg_id = this_attr->address;
iio_evgen->regs[this_attr->address].reg_data = event;

- irq_sim_fire(&iio_evgen->irq_sim, this_attr->address);
+ irq = irq_find_mapping(iio_evgen->irq_sim_domain, this_attr->address);
+ irq_sim_fire(irq);

return len;
}
diff --git a/include/linux/irq_sim.h b/include/linux/irq_sim.h
index 4500d453a63e..26bf6164dcc7 100644
--- a/include/linux/irq_sim.h
+++ b/include/linux/irq_sim.h
@@ -1,41 +1,27 @@
/* SPDX-License-Identifier: GPL-2.0+ */
/*
* Copyright (C) 2017-2018 Bartosz Golaszewski <brgl@xxxxxxxx>
+ * Copyright (C) 2020 Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
*/

#ifndef _LINUX_IRQ_SIM_H
#define _LINUX_IRQ_SIM_H

-#include <linux/irq_work.h>
#include <linux/device.h>
+#include <linux/fwnode.h>
+#include <linux/irqdomain.h>

/*
* Provides a framework for allocating simulated interrupts which can be
* requested like normal irqs and enqueued from process context.
*/

-struct irq_sim_work_ctx {
- struct irq_work work;
- unsigned long *pending;
-};
-
-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);
-int devm_irq_sim_init(struct device *dev, 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);
+struct irq_domain *irq_domain_create_sim(struct fwnode_handle *fwnode,
+ unsigned int num_irqs);
+struct irq_domain *devm_irq_domain_create_sim(struct device *dev,
+ struct fwnode_handle *fwnode,
+ unsigned int num_irqs);
+void irq_domain_remove_sim(struct irq_domain *domain);
+void irq_sim_fire(int virq);

#endif /* _LINUX_IRQ_SIM_H */
diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig
index 20d501af4f2e..d63c324895ea 100644
--- a/kernel/irq/Kconfig
+++ b/kernel/irq/Kconfig
@@ -72,6 +72,7 @@ config IRQ_DOMAIN
config IRQ_SIM
bool
select IRQ_WORK
+ select IRQ_DOMAIN

# Support for hierarchical irq domains
config IRQ_DOMAIN_HIERARCHY
diff --git a/kernel/irq/irq_sim.c b/kernel/irq/irq_sim.c
index b992f88c5613..575c1e3d32a9 100644
--- a/kernel/irq/irq_sim.c
+++ b/kernel/irq/irq_sim.c
@@ -1,14 +1,30 @@
// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2017-2018 Bartosz Golaszewski <brgl@xxxxxxxx>
+ * Copyright (C) 2020 Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
*/

-#include <linux/slab.h>
-#include <linux/irq_sim.h>
#include <linux/irq.h>
+#include <linux/irq_sim.h>
+#include <linux/irq_work.h>
+#include <linux/slab.h>
+
+struct irq_sim_work_ctx {
+ struct irq_work work;
+ int irq_base;
+ unsigned int irq_count;
+ unsigned long *pending;
+ struct irq_domain *domain;
+};
+
+struct irq_sim_irq_ctx {
+ int irqnum;
+ bool enabled;
+ struct irq_sim_work_ctx *work_ctx;
+};

struct irq_sim_devres {
- struct irq_sim *sim;
+ struct irq_domain *domain;
};

static void irq_sim_irqmask(struct irq_data *data)
@@ -47,148 +63,179 @@ static void irq_sim_handle_irq(struct irq_work *work)
{
struct irq_sim_work_ctx *work_ctx;
unsigned int offset = 0;
- struct irq_sim *sim;
int irqnum;

work_ctx = container_of(work, struct irq_sim_work_ctx, work);
- sim = container_of(work_ctx, struct irq_sim, work_ctx);

- while (!bitmap_empty(work_ctx->pending, sim->irq_count)) {
+ while (!bitmap_empty(work_ctx->pending, work_ctx->irq_count)) {
offset = find_next_bit(work_ctx->pending,
- sim->irq_count, offset);
+ work_ctx->irq_count, offset);
clear_bit(offset, work_ctx->pending);
- irqnum = irq_sim_irqnum(sim, offset);
+ irqnum = irq_find_mapping(work_ctx->domain, offset);
handle_simple_irq(irq_to_desc(irqnum));
}
}

+static int irq_sim_domain_map(struct irq_domain *domain,
+ unsigned int virq, irq_hw_number_t hw)
+{
+ struct irq_sim_work_ctx *work_ctx = domain->host_data;
+ struct irq_sim_irq_ctx *irq_ctx;
+
+ irq_ctx = kzalloc(sizeof(*irq_ctx), GFP_KERNEL);
+ if (!irq_ctx)
+ return -ENOMEM;
+
+ irq_set_chip(virq, &irq_sim_irqchip);
+ irq_set_chip_data(virq, irq_ctx);
+ irq_set_handler(virq, handle_simple_irq);
+ irq_modify_status(virq, IRQ_NOREQUEST | IRQ_NOAUTOEN, IRQ_NOPROBE);
+ irq_ctx->work_ctx = work_ctx;
+
+ return 0;
+}
+
+static void irq_sim_domain_unmap(struct irq_domain *domain, unsigned int virq)
+{
+ struct irq_sim_irq_ctx *irq_ctx;
+ struct irq_data *irqd;
+
+ irqd = irq_domain_get_irq_data(domain, virq);
+ irq_ctx = irq_data_get_irq_chip_data(irqd);
+
+ irq_set_handler(virq, NULL);
+ irq_domain_reset_irq_data(irqd);
+ kfree(irq_ctx);
+}
+
+static const struct irq_domain_ops irq_sim_domain_ops = {
+ .map = irq_sim_domain_map,
+ .unmap = irq_sim_domain_unmap,
+};
+
/**
- * irq_sim_init - Initialize the interrupt simulator: allocate a range of
- * dummy interrupts.
+ * irq_domain_create_sim - Create a new interrupt simulator irq_domain and
+ * allocate a range of dummy interrupts.
*
- * @sim: The interrupt simulator object to initialize.
- * @num_irqs: Number of interrupts to allocate
+ * @fnode: struct fwnode_handle to be associated with this domain.
+ * @num_irqs: Number of interrupts to allocate.
*
- * On success: return the base of the allocated interrupt range.
- * On failure: a negative errno.
+ * On success: return a new irq_domain object.
+ * On failure: a negative errno wrapped with ERR_PTR().
*/
-int irq_sim_init(struct irq_sim *sim, unsigned int num_irqs)
+struct irq_domain *irq_domain_create_sim(struct fwnode_handle *fwnode,
+ unsigned int num_irqs)
{
- int i;
+ struct irq_sim_work_ctx *work_ctx;

- sim->irqs = kmalloc_array(num_irqs, sizeof(*sim->irqs), GFP_KERNEL);
- if (!sim->irqs)
- return -ENOMEM;
+ work_ctx = kmalloc(sizeof(*work_ctx), GFP_KERNEL);
+ if (!work_ctx)
+ goto err_out;

- sim->irq_base = irq_alloc_descs(-1, 0, num_irqs, 0);
- if (sim->irq_base < 0) {
- kfree(sim->irqs);
- return sim->irq_base;
- }
+ work_ctx->pending = bitmap_zalloc(num_irqs, GFP_KERNEL);
+ if (!work_ctx->pending)
+ goto err_free_work_ctx;

- sim->work_ctx.pending = bitmap_zalloc(num_irqs, GFP_KERNEL);
- if (!sim->work_ctx.pending) {
- kfree(sim->irqs);
- irq_free_descs(sim->irq_base, num_irqs);
- return -ENOMEM;
- }
+ work_ctx->domain = irq_domain_create_linear(fwnode, num_irqs,
+ &irq_sim_domain_ops,
+ work_ctx);
+ if (!work_ctx->domain)
+ goto err_free_bitmap;

- 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);
- }
+ work_ctx->irq_count = num_irqs;
+ init_irq_work(&work_ctx->work, irq_sim_handle_irq);

- init_irq_work(&sim->work_ctx.work, irq_sim_handle_irq);
- sim->irq_count = num_irqs;
+ return work_ctx->domain;

- return sim->irq_base;
+err_free_bitmap:
+ bitmap_free(work_ctx->pending);
+err_free_work_ctx:
+ kfree(work_ctx);
+err_out:
+ return ERR_PTR(-ENOMEM);
}
-EXPORT_SYMBOL_GPL(irq_sim_init);
+EXPORT_SYMBOL_GPL(irq_domain_create_sim);

/**
- * irq_sim_fini - Deinitialize the interrupt simulator: free the interrupt
- * descriptors and allocated memory.
+ * irq_domain_remove_sim - Deinitialize the interrupt simulator domain: free
+ * the interrupt descriptors and allocated memory.
*
- * @sim: The interrupt simulator to tear down.
+ * @domain: The interrupt simulator domain to tear down.
*/
-void irq_sim_fini(struct irq_sim *sim)
+void irq_domain_remove_sim(struct irq_domain *domain)
{
- irq_work_sync(&sim->work_ctx.work);
- bitmap_free(sim->work_ctx.pending);
- irq_free_descs(sim->irq_base, sim->irq_count);
- kfree(sim->irqs);
+ struct irq_sim_work_ctx *work_ctx = domain->host_data;
+
+ irq_work_sync(&work_ctx->work);
+ bitmap_free(work_ctx->pending);
+ kfree(work_ctx);
+
+ irq_domain_remove(domain);
}
-EXPORT_SYMBOL_GPL(irq_sim_fini);
+EXPORT_SYMBOL_GPL(irq_domain_remove_sim);

-static void devm_irq_sim_release(struct device *dev, void *res)
+static void devm_irq_domain_release_sim(struct device *dev, void *res)
{
struct irq_sim_devres *this = res;

- irq_sim_fini(this->sim);
+ irq_domain_remove_sim(this->domain);
}

/**
- * irq_sim_init - Initialize the interrupt simulator for a managed device.
+ * devm_irq_domain_create_sim - Create a new interrupt simulator for
+ * a managed device.
*
* @dev: Device to initialize the simulator object for.
- * @sim: The interrupt simulator object to initialize.
+ * @fnode: struct fwnode_handle to be associated with this domain.
* @num_irqs: Number of interrupts to allocate
*
- * On success: return the base of the allocated interrupt range.
- * On failure: a negative errno.
+ * On success: return a new irq_domain object.
+ * On failure: a negative errno wrapped with ERR_PTR().
*/
-int devm_irq_sim_init(struct device *dev, struct irq_sim *sim,
- unsigned int num_irqs)
+struct irq_domain *devm_irq_domain_create_sim(struct device *dev,
+ struct fwnode_handle *fwnode,
+ unsigned int num_irqs)
{
struct irq_sim_devres *dr;
- int rv;

- dr = devres_alloc(devm_irq_sim_release, sizeof(*dr), GFP_KERNEL);
+ dr = devres_alloc(devm_irq_domain_release_sim,
+ sizeof(*dr), GFP_KERNEL);
if (!dr)
- return -ENOMEM;
+ return ERR_PTR(-ENOMEM);

- rv = irq_sim_init(sim, num_irqs);
- if (rv < 0) {
+ dr->domain = irq_domain_create_sim(fwnode, num_irqs);
+ if (IS_ERR(dr->domain)) {
devres_free(dr);
- return rv;
+ return dr->domain;
}

- dr->sim = sim;
devres_add(dev, dr);
-
- return rv;
+ return dr->domain;
}
-EXPORT_SYMBOL_GPL(devm_irq_sim_init);
+EXPORT_SYMBOL_GPL(devm_irq_domain_create_sim);

/**
* irq_sim_fire - Enqueue an interrupt.
*
- * @sim: The interrupt simulator object.
- * @offset: Offset of the simulated interrupt which should be fired.
+ * @virq: Virtual interrupt number to fire. It must be associated with
+ * an existing interrupt simulator.
*/
-void irq_sim_fire(struct irq_sim *sim, unsigned int offset)
+void irq_sim_fire(int virq)
{
- if (sim->irqs[offset].enabled) {
- set_bit(offset, sim->work_ctx.pending);
- irq_work_queue(&sim->work_ctx.work);
+ struct irq_sim_irq_ctx *irq_ctx;
+ struct irq_data *irqd;
+
+ irqd = irq_get_irq_data(virq);
+ if (!irqd) {
+ pr_warn_ratelimited("%s: invalid irq number\n", __func__);
+ return;
}
-}
-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;
+ irq_ctx = irq_data_get_irq_chip_data(irqd);
+
+ if (irq_ctx->enabled) {
+ set_bit(irqd_to_hwirq(irqd), irq_ctx->work_ctx->pending);
+ irq_work_queue(&irq_ctx->work_ctx->work);
+ }
}
-EXPORT_SYMBOL_GPL(irq_sim_irqnum);
+EXPORT_SYMBOL_GPL(irq_sim_fire);
--
2.25.0