Merge branch 'irq/for-gpio' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into devel
diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt
index 30e04f7..69f08c0 100644
--- a/Documentation/driver-model/devres.txt
+++ b/Documentation/driver-model/devres.txt
@@ -312,6 +312,7 @@
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.h b/include/linux/irq.h
index d2d54379..d4728bf 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -568,6 +568,8 @@ extern int irq_chip_compose_msi_msg(struct irq_data *data, struct msi_msg *msg);
extern int irq_chip_pm_get(struct irq_data *data);
extern int irq_chip_pm_put(struct irq_data *data);
#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
+extern void handle_fasteoi_ack_irq(struct irq_desc *desc);
+extern void handle_fasteoi_mask_irq(struct irq_desc *desc);
extern void irq_chip_enable_parent(struct irq_data *data);
extern void irq_chip_disable_parent(struct irq_data *data);
extern void irq_chip_ack_parent(struct irq_data *data);
diff --git a/include/linux/irq_sim.h b/include/linux/irq_sim.h
new file mode 100644
index 0000000..0380d89
--- /dev/null
+++ b/include/linux/irq_sim.h
@@ -0,0 +1,44 @@
+#ifndef _LINUX_IRQ_SIM_H
+#define _LINUX_IRQ_SIM_H
+/*
+ * Copyright (C) 2017 Bartosz Golaszewski <brgl@bgdev.pl>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ */
+
+#include <linux/irq_work.h>
+#include <linux/device.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;
+ 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);
+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);
+
+#endif /* _LINUX_IRQ_SIM_H */
diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h
index cac77a5..2318f29 100644
--- a/include/linux/irqdomain.h
+++ b/include/linux/irqdomain.h
@@ -460,6 +460,9 @@ extern void irq_domain_free_irqs_common(struct irq_domain *domain,
extern void irq_domain_free_irqs_top(struct irq_domain *domain,
unsigned int virq, unsigned int nr_irqs);
+extern int irq_domain_push_irq(struct irq_domain *domain, int virq, void *arg);
+extern int irq_domain_pop_irq(struct irq_domain *domain, int virq);
+
extern int irq_domain_alloc_irqs_parent(struct irq_domain *domain,
unsigned int irq_base,
unsigned int nr_irqs, void *arg);
diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig
index 27c4e77..a117adf 100644
--- a/kernel/irq/Kconfig
+++ b/kernel/irq/Kconfig
@@ -63,11 +63,20 @@
config IRQ_DOMAIN
bool
+# Support for simulated interrupts
+config IRQ_SIM
+ bool
+ select IRQ_WORK
+
# Support for hierarchical irq domains
config IRQ_DOMAIN_HIERARCHY
bool
select IRQ_DOMAIN
+# Support for hierarchical fasteoi+edge and fasteoi+level handlers
+config IRQ_FASTEOI_HIERARCHY_HANDLERS
+ bool
+
# Generic IRQ IPI support
config GENERIC_IRQ_IPI
bool
diff --git a/kernel/irq/Makefile b/kernel/irq/Makefile
index e4aef735..1970caf 100644
--- a/kernel/irq/Makefile
+++ b/kernel/irq/Makefile
@@ -4,6 +4,7 @@
obj-$(CONFIG_GENERIC_IRQ_CHIP) += generic-chip.o
obj-$(CONFIG_GENERIC_IRQ_PROBE) += autoprobe.o
obj-$(CONFIG_IRQ_DOMAIN) += irqdomain.o
+obj-$(CONFIG_IRQ_SIM) += irq_sim.o
obj-$(CONFIG_PROC_FS) += proc.o
obj-$(CONFIG_GENERIC_PENDING_IRQ) += migration.o
obj-$(CONFIG_GENERIC_IRQ_MIGRATION) += cpuhotplug.o
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index a3cc37c..2395898 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -1092,6 +1092,112 @@ void irq_cpu_offline(void)
}
#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
+
+#ifdef CONFIG_IRQ_FASTEOI_HIERARCHY_HANDLERS
+/**
+ * handle_fasteoi_ack_irq - irq handler for edge hierarchy
+ * stacked on transparent controllers
+ *
+ * @desc: the interrupt description structure for this irq
+ *
+ * Like handle_fasteoi_irq(), but for use with hierarchy where
+ * the irq_chip also needs to have its ->irq_ack() function
+ * called.
+ */
+void handle_fasteoi_ack_irq(struct irq_desc *desc)
+{
+ struct irq_chip *chip = desc->irq_data.chip;
+
+ raw_spin_lock(&desc->lock);
+
+ if (!irq_may_run(desc))
+ goto out;
+
+ desc->istate &= ~(IRQS_REPLAY | IRQS_WAITING);
+
+ /*
+ * If its disabled or no action available
+ * then mask it and get out of here:
+ */
+ if (unlikely(!desc->action || irqd_irq_disabled(&desc->irq_data))) {
+ desc->istate |= IRQS_PENDING;
+ mask_irq(desc);
+ goto out;
+ }
+
+ kstat_incr_irqs_this_cpu(desc);
+ if (desc->istate & IRQS_ONESHOT)
+ mask_irq(desc);
+
+ /* Start handling the irq */
+ desc->irq_data.chip->irq_ack(&desc->irq_data);
+
+ preflow_handler(desc);
+ handle_irq_event(desc);
+
+ cond_unmask_eoi_irq(desc, chip);
+
+ raw_spin_unlock(&desc->lock);
+ return;
+out:
+ if (!(chip->flags & IRQCHIP_EOI_IF_HANDLED))
+ chip->irq_eoi(&desc->irq_data);
+ raw_spin_unlock(&desc->lock);
+}
+EXPORT_SYMBOL_GPL(handle_fasteoi_ack_irq);
+
+/**
+ * handle_fasteoi_mask_irq - irq handler for level hierarchy
+ * stacked on transparent controllers
+ *
+ * @desc: the interrupt description structure for this irq
+ *
+ * Like handle_fasteoi_irq(), but for use with hierarchy where
+ * the irq_chip also needs to have its ->irq_mask_ack() function
+ * called.
+ */
+void handle_fasteoi_mask_irq(struct irq_desc *desc)
+{
+ struct irq_chip *chip = desc->irq_data.chip;
+
+ raw_spin_lock(&desc->lock);
+ mask_ack_irq(desc);
+
+ if (!irq_may_run(desc))
+ goto out;
+
+ desc->istate &= ~(IRQS_REPLAY | IRQS_WAITING);
+
+ /*
+ * If its disabled or no action available
+ * then mask it and get out of here:
+ */
+ if (unlikely(!desc->action || irqd_irq_disabled(&desc->irq_data))) {
+ desc->istate |= IRQS_PENDING;
+ mask_irq(desc);
+ goto out;
+ }
+
+ kstat_incr_irqs_this_cpu(desc);
+ if (desc->istate & IRQS_ONESHOT)
+ mask_irq(desc);
+
+ preflow_handler(desc);
+ handle_irq_event(desc);
+
+ cond_unmask_eoi_irq(desc, chip);
+
+ raw_spin_unlock(&desc->lock);
+ return;
+out:
+ if (!(chip->flags & IRQCHIP_EOI_IF_HANDLED))
+ chip->irq_eoi(&desc->irq_data);
+ raw_spin_unlock(&desc->lock);
+}
+EXPORT_SYMBOL_GPL(handle_fasteoi_mask_irq);
+
+#endif /* CONFIG_IRQ_FASTEOI_HIERARCHY_HANDLERS */
+
/**
* irq_chip_enable_parent - Enable the parent interrupt (defaults to unmask if
* NULL)
@@ -1105,6 +1211,7 @@ void irq_chip_enable_parent(struct irq_data *data)
else
data->chip->irq_unmask(data);
}
+EXPORT_SYMBOL_GPL(irq_chip_enable_parent);
/**
* irq_chip_disable_parent - Disable the parent interrupt (defaults to mask if
@@ -1119,6 +1226,7 @@ void irq_chip_disable_parent(struct irq_data *data)
else
data->chip->irq_mask(data);
}
+EXPORT_SYMBOL_GPL(irq_chip_disable_parent);
/**
* irq_chip_ack_parent - Acknowledge the parent interrupt
@@ -1181,6 +1289,7 @@ int irq_chip_set_affinity_parent(struct irq_data *data,
return -ENOSYS;
}
+EXPORT_SYMBOL_GPL(irq_chip_set_affinity_parent);
/**
* irq_chip_set_type_parent - Set IRQ type on the parent interrupt
diff --git a/kernel/irq/irq_sim.c b/kernel/irq/irq_sim.c
new file mode 100644
index 0000000..24caabf
--- /dev/null
+++ b/kernel/irq/irq_sim.c
@@ -0,0 +1,164 @@
+/*
+ * Copyright (C) 2017 Bartosz Golaszewski <brgl@bgdev.pl>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ */
+
+#include <linux/irq_sim.h>
+#include <linux/irq.h>
+
+struct irq_sim_devres {
+ struct irq_sim *sim;
+};
+
+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);
+
+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.
+ *
+ * @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);
diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index f1f2514..1ff9912 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -455,6 +455,31 @@ void irq_set_default_host(struct irq_domain *domain)
}
EXPORT_SYMBOL_GPL(irq_set_default_host);
+static void irq_domain_clear_mapping(struct irq_domain *domain,
+ irq_hw_number_t hwirq)
+{
+ if (hwirq < domain->revmap_size) {
+ domain->linear_revmap[hwirq] = 0;
+ } else {
+ mutex_lock(&revmap_trees_mutex);
+ radix_tree_delete(&domain->revmap_tree, hwirq);
+ mutex_unlock(&revmap_trees_mutex);
+ }
+}
+
+static void irq_domain_set_mapping(struct irq_domain *domain,
+ irq_hw_number_t hwirq,
+ struct irq_data *irq_data)
+{
+ if (hwirq < domain->revmap_size) {
+ domain->linear_revmap[hwirq] = irq_data->irq;
+ } else {
+ mutex_lock(&revmap_trees_mutex);
+ radix_tree_insert(&domain->revmap_tree, hwirq, irq_data);
+ mutex_unlock(&revmap_trees_mutex);
+ }
+}
+
void irq_domain_disassociate(struct irq_domain *domain, unsigned int irq)
{
struct irq_data *irq_data = irq_get_irq_data(irq);
@@ -483,13 +508,7 @@ void irq_domain_disassociate(struct irq_domain *domain, unsigned int irq)
domain->mapcount--;
/* Clear reverse map for this hwirq */
- if (hwirq < domain->revmap_size) {
- domain->linear_revmap[hwirq] = 0;
- } else {
- mutex_lock(&revmap_trees_mutex);
- radix_tree_delete(&domain->revmap_tree, hwirq);
- mutex_unlock(&revmap_trees_mutex);
- }
+ irq_domain_clear_mapping(domain, hwirq);
}
int irq_domain_associate(struct irq_domain *domain, unsigned int virq,
@@ -533,13 +552,7 @@ int irq_domain_associate(struct irq_domain *domain, unsigned int virq,
}
domain->mapcount++;
- if (hwirq < domain->revmap_size) {
- domain->linear_revmap[hwirq] = virq;
- } else {
- mutex_lock(&revmap_trees_mutex);
- radix_tree_insert(&domain->revmap_tree, hwirq, irq_data);
- mutex_unlock(&revmap_trees_mutex);
- }
+ irq_domain_set_mapping(domain, hwirq, irq_data);
mutex_unlock(&irq_domain_mutex);
irq_clear_status_flags(virq, IRQ_NOREQUEST);
@@ -1138,16 +1151,9 @@ static void irq_domain_insert_irq(int virq)
for (data = irq_get_irq_data(virq); data; data = data->parent_data) {
struct irq_domain *domain = data->domain;
- irq_hw_number_t hwirq = data->hwirq;
domain->mapcount++;
- if (hwirq < domain->revmap_size) {
- domain->linear_revmap[hwirq] = virq;
- } else {
- mutex_lock(&revmap_trees_mutex);
- radix_tree_insert(&domain->revmap_tree, hwirq, data);
- mutex_unlock(&revmap_trees_mutex);
- }
+ irq_domain_set_mapping(domain, data->hwirq, data);
/* If not already assigned, give the domain the chip's name */
if (!domain->name && data->chip)
@@ -1171,13 +1177,7 @@ static void irq_domain_remove_irq(int virq)
irq_hw_number_t hwirq = data->hwirq;
domain->mapcount--;
- if (hwirq < domain->revmap_size) {
- domain->linear_revmap[hwirq] = 0;
- } else {
- mutex_lock(&revmap_trees_mutex);
- radix_tree_delete(&domain->revmap_tree, hwirq);
- mutex_unlock(&revmap_trees_mutex);
- }
+ irq_domain_clear_mapping(domain, hwirq);
}
}
@@ -1362,7 +1362,8 @@ static void irq_domain_free_irqs_hierarchy(struct irq_domain *domain,
unsigned int irq_base,
unsigned int nr_irqs)
{
- domain->ops->free(domain, irq_base, nr_irqs);
+ if (domain->ops->free)
+ domain->ops->free(domain, irq_base, nr_irqs);
}
int irq_domain_alloc_irqs_hierarchy(struct irq_domain *domain,
@@ -1448,6 +1449,175 @@ int __irq_domain_alloc_irqs(struct irq_domain *domain, int irq_base,
return ret;
}
+/* The irq_data was moved, fix the revmap to refer to the new location */
+static void irq_domain_fix_revmap(struct irq_data *d)
+{
+ void **slot;
+
+ if (d->hwirq < d->domain->revmap_size)
+ return; /* Not using radix tree. */
+
+ /* Fix up the revmap. */
+ mutex_lock(&revmap_trees_mutex);
+ slot = radix_tree_lookup_slot(&d->domain->revmap_tree, d->hwirq);
+ if (slot)
+ radix_tree_replace_slot(&d->domain->revmap_tree, slot, d);
+ mutex_unlock(&revmap_trees_mutex);
+}
+
+/**
+ * irq_domain_push_irq() - Push a domain in to the top of a hierarchy.
+ * @domain: Domain to push.
+ * @virq: Irq to push the domain in to.
+ * @arg: Passed to the irq_domain_ops alloc() function.
+ *
+ * For an already existing irqdomain hierarchy, as might be obtained
+ * via a call to pci_enable_msix(), add an additional domain to the
+ * head of the processing chain. Must be called before request_irq()
+ * has been called.
+ */
+int irq_domain_push_irq(struct irq_domain *domain, int virq, void *arg)
+{
+ struct irq_data *child_irq_data;
+ struct irq_data *root_irq_data = irq_get_irq_data(virq);
+ struct irq_desc *desc;
+ int rv = 0;
+
+ /*
+ * Check that no action has been set, which indicates the virq
+ * is in a state where this function doesn't have to deal with
+ * races between interrupt handling and maintaining the
+ * hierarchy. This will catch gross misuse. Attempting to
+ * make the check race free would require holding locks across
+ * calls to struct irq_domain_ops->alloc(), which could lead
+ * to deadlock, so we just do a simple check before starting.
+ */
+ desc = irq_to_desc(virq);
+ if (!desc)
+ return -EINVAL;
+ if (WARN_ON(desc->action))
+ return -EBUSY;
+
+ if (domain == NULL)
+ return -EINVAL;
+
+ if (WARN_ON(!irq_domain_is_hierarchy(domain)))
+ return -EINVAL;
+
+ if (domain->parent != root_irq_data->domain)
+ return -EINVAL;
+
+ if (!root_irq_data)
+ return -EINVAL;
+
+ child_irq_data = kzalloc_node(sizeof(*child_irq_data), GFP_KERNEL,
+ irq_data_get_node(root_irq_data));
+ if (!child_irq_data)
+ return -ENOMEM;
+
+ mutex_lock(&irq_domain_mutex);
+
+ /* Copy the original irq_data. */
+ *child_irq_data = *root_irq_data;
+
+ /*
+ * Overwrite the root_irq_data, which is embedded in struct
+ * irq_desc, with values for this domain.
+ */
+ root_irq_data->parent_data = child_irq_data;
+ root_irq_data->domain = domain;
+ root_irq_data->mask = 0;
+ root_irq_data->hwirq = 0;
+ root_irq_data->chip = NULL;
+ root_irq_data->chip_data = NULL;
+
+ /* May (probably does) set hwirq, chip, etc. */
+ rv = irq_domain_alloc_irqs_hierarchy(domain, virq, 1, arg);
+ if (rv) {
+ /* Restore the original irq_data. */
+ *root_irq_data = *child_irq_data;
+ goto error;
+ }
+
+ irq_domain_fix_revmap(child_irq_data);
+ irq_domain_set_mapping(domain, root_irq_data->hwirq, root_irq_data);
+
+error:
+ mutex_unlock(&irq_domain_mutex);
+
+ return rv;
+}
+EXPORT_SYMBOL_GPL(irq_domain_push_irq);
+
+/**
+ * irq_domain_pop_irq() - Remove a domain from the top of a hierarchy.
+ * @domain: Domain to remove.
+ * @virq: Irq to remove the domain from.
+ *
+ * Undo the effects of a call to irq_domain_push_irq(). Must be
+ * called either before request_irq() or after free_irq().
+ */
+int irq_domain_pop_irq(struct irq_domain *domain, int virq)
+{
+ struct irq_data *root_irq_data = irq_get_irq_data(virq);
+ struct irq_data *child_irq_data;
+ struct irq_data *tmp_irq_data;
+ struct irq_desc *desc;
+
+ /*
+ * Check that no action is set, which indicates the virq is in
+ * a state where this function doesn't have to deal with races
+ * between interrupt handling and maintaining the hierarchy.
+ * This will catch gross misuse. Attempting to make the check
+ * race free would require holding locks across calls to
+ * struct irq_domain_ops->free(), which could lead to
+ * deadlock, so we just do a simple check before starting.
+ */
+ desc = irq_to_desc(virq);
+ if (!desc)
+ return -EINVAL;
+ if (WARN_ON(desc->action))
+ return -EBUSY;
+
+ if (domain == NULL)
+ return -EINVAL;
+
+ if (!root_irq_data)
+ return -EINVAL;
+
+ tmp_irq_data = irq_domain_get_irq_data(domain, virq);
+
+ /* We can only "pop" if this domain is at the top of the list */
+ if (WARN_ON(root_irq_data != tmp_irq_data))
+ return -EINVAL;
+
+ if (WARN_ON(root_irq_data->domain != domain))
+ return -EINVAL;
+
+ child_irq_data = root_irq_data->parent_data;
+ if (WARN_ON(!child_irq_data))
+ return -EINVAL;
+
+ mutex_lock(&irq_domain_mutex);
+
+ root_irq_data->parent_data = NULL;
+
+ irq_domain_clear_mapping(domain, root_irq_data->hwirq);
+ irq_domain_free_irqs_hierarchy(domain, virq, 1);
+
+ /* Restore the original irq_data. */
+ *root_irq_data = *child_irq_data;
+
+ irq_domain_fix_revmap(root_irq_data);
+
+ mutex_unlock(&irq_domain_mutex);
+
+ kfree(child_irq_data);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(irq_domain_pop_irq);
+
/**
* irq_domain_free_irqs - Free IRQ number and associated data structures
* @virq: base IRQ number