arch/powerpc/platforms/powernv/opal-irqchip.c - kernel/bruno - Git at Google

 /*
  * This file implements an irqchip for OPAL events. Whenever there is
  * an interrupt that is handled by OPAL we get passed a list of events
  * that Linux needs to do something about. These basically look like
  * interrupts to Linux so we implement an irqchip to handle them.
  *
  * Copyright Alistair Popple, IBM Corporation 2014.
  *
  * 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/bitops.h>
 #include <linux/irq.h>
 #include <linux/irqchip.h>
 #include <linux/irqdomain.h>
 #include <linux/interrupt.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/kthread.h>
 #include <linux/delay.h>
 #include <linux/slab.h>
 #include <linux/irq_work.h>

 #include <asm/machdep.h>
 #include <asm/opal.h>

 #include "powernv.h"

 /* Maximum number of events supported by OPAL firmware */
 #define MAX_NUM_EVENTS 64

 struct opal_event_irqchip {
 	struct irq_chip irqchip;
 	struct irq_domain *domain;
 	unsigned long mask;
 };
 static struct opal_event_irqchip opal_event_irqchip;

 static unsigned int opal_irq_count;
 static unsigned int *opal_irqs;

 static void opal_handle_irq_work(struct irq_work *work);
 static u64 last_outstanding_events;
 static struct irq_work opal_event_irq_work = {
 	.func = opal_handle_irq_work,
 };

 void opal_handle_events(uint64_t events)
 {
 	int virq, hwirq = 0;
 	u64 mask = opal_event_irqchip.mask;

 	if (!in_irq() && (events & mask)) {
 		last_outstanding_events = events;
 		irq_work_queue(&opal_event_irq_work);
 		return;
 	}

 	while (events & mask) {
 		hwirq = fls64(events) - 1;
 		if (BIT_ULL(hwirq) & mask) {
 			virq = irq_find_mapping(opal_event_irqchip.domain,
 						hwirq);
 			if (virq)
 				generic_handle_irq(virq);
 		}
 		events &= ~BIT_ULL(hwirq);
 	}
 }

 static void opal_event_mask(struct irq_data *d)
 {
 	clear_bit(d->hwirq, &opal_event_irqchip.mask);
 }

 static void opal_event_unmask(struct irq_data *d)
 {
 	__be64 events;

 	set_bit(d->hwirq, &opal_event_irqchip.mask);

 	opal_poll_events(&events);
 	last_outstanding_events = be64_to_cpu(events);

 	/*
 	 * We can't just handle the events now with opal_handle_events().
 	 * If we did we would deadlock when opal_event_unmask() is called from
 	 * handle_level_irq() with the irq descriptor lock held, because
 	 * calling opal_handle_events() would call generic_handle_irq() and
 	 * then handle_level_irq() which would try to take the descriptor lock
 	 * again. Instead queue the events for later.
 	 */
 	if (last_outstanding_events & opal_event_irqchip.mask)
 		/* Need to retrigger the interrupt */
 		irq_work_queue(&opal_event_irq_work);
 }

 static int opal_event_set_type(struct irq_data *d, unsigned int flow_type)
 {
 	/*
 	 * For now we only support level triggered events. The irq
 	 * handler will be called continuously until the event has
 	 * been cleared in OPAL.
 	 */
 	if (flow_type != IRQ_TYPE_LEVEL_HIGH)
 		return -EINVAL;

 	return 0;
 }

 static struct opal_event_irqchip opal_event_irqchip = {
 	.irqchip = {
 		.name = "OPAL EVT",
 		.irq_mask = opal_event_mask,
 		.irq_unmask = opal_event_unmask,
 		.irq_set_type = opal_event_set_type,
 	},
 	.mask = 0,
 };

 static int opal_event_map(struct irq_domain *d, unsigned int irq,
 			irq_hw_number_t hwirq)
 {
 	irq_set_chip_data(irq, &opal_event_irqchip);
 	irq_set_chip_and_handler(irq, &opal_event_irqchip.irqchip,
 				handle_level_irq);

 	return 0;
 }

 static irqreturn_t opal_interrupt(int irq, void *data)
 {
 	__be64 events;

 	opal_handle_interrupt(virq_to_hw(irq), &events);
 	opal_handle_events(be64_to_cpu(events));

 	return IRQ_HANDLED;
 }

 static void opal_handle_irq_work(struct irq_work *work)
 {
 	opal_handle_events(last_outstanding_events);
 }

 static int opal_event_match(struct irq_domain *h, struct device_node *node,
 			    enum irq_domain_bus_token bus_token)
 {
 	return irq_domain_get_of_node(h) == node;
 }

 static int opal_event_xlate(struct irq_domain *h, struct device_node *np,
 			   const u32 *intspec, unsigned int intsize,
 			   irq_hw_number_t *out_hwirq, unsigned int *out_flags)
 {
 	*out_hwirq = intspec[0];
 	*out_flags = IRQ_TYPE_LEVEL_HIGH;

 	return 0;
 }

 static const struct irq_domain_ops opal_event_domain_ops = {
 	.match	= opal_event_match,
 	.map	= opal_event_map,
 	.xlate	= opal_event_xlate,
 };

 void opal_event_shutdown(void)
 {
 	unsigned int i;

 	/* First free interrupts, which will also mask them */
 	for (i = 0; i < opal_irq_count; i++) {
 		if (opal_irqs[i])
 			free_irq(opal_irqs[i], NULL);
 		opal_irqs[i] = 0;
 	}
 }

 int __init opal_event_init(void)
 {
 	struct device_node *dn, *opal_node;
 	const __be32 *irqs;
 	int i, irqlen, rc = 0;

 	opal_node = of_find_node_by_path("/ibm,opal");
 	if (!opal_node) {
 		pr_warn("opal: Node not found\n");
 		return -ENODEV;
 	}

 	/* If dn is NULL it means the domain won't be linked to a DT
 	 * node so therefore irq_of_parse_and_map(...) wont work. But
 	 * that shouldn't be problem because if we're running a
 	 * version of skiboot that doesn't have the dn then the
 	 * devices won't have the correct properties and will have to
 	 * fall back to the legacy method (opal_event_request(...))
 	 * anyway. */
 	dn = of_find_compatible_node(NULL, NULL, "ibm,opal-event");
 	opal_event_irqchip.domain = irq_domain_add_linear(dn, MAX_NUM_EVENTS,
 				&opal_event_domain_ops, &opal_event_irqchip);
 	of_node_put(dn);
 	if (!opal_event_irqchip.domain) {
 		pr_warn("opal: Unable to create irq domain\n");
 		rc = -ENOMEM;
 		goto out;
 	}

 	/* Get interrupt property */
 	irqs = of_get_property(opal_node, "opal-interrupts", &irqlen);
 	opal_irq_count = irqs ? (irqlen / 4) : 0;
 	pr_debug("Found %d interrupts reserved for OPAL\n", opal_irq_count);

 	/* Install interrupt handlers */
 	opal_irqs = kcalloc(opal_irq_count, sizeof(*opal_irqs), GFP_KERNEL);
 	for (i = 0; irqs && i < opal_irq_count; i++, irqs++) {
 		unsigned int irq, virq;

 		/* Get hardware and virtual IRQ */
 		irq = be32_to_cpup(irqs);
 		virq = irq_create_mapping(NULL, irq);
 		if (virq == NO_IRQ) {
 			pr_warn("Failed to map irq 0x%x\n", irq);
 			continue;
 		}

 		/* Install interrupt handler */
 		rc = request_irq(virq, opal_interrupt, 0, "opal", NULL);
 		if (rc) {
 			irq_dispose_mapping(virq);
 			pr_warn("Error %d requesting irq %d (0x%x)\n",
 				 rc, virq, irq);
 			continue;
 		}

 		/* Cache IRQ */
 		opal_irqs[i] = virq;
 	}

 out:
 	of_node_put(opal_node);
 	return rc;
 }
 machine_arch_initcall(powernv, opal_event_init);

 /**
  * opal_event_request(unsigned int opal_event_nr) - Request an event
  * @opal_event_nr: the opal event number to request
  *
  * This routine can be used to find the linux virq number which can
  * then be passed to request_irq to assign a handler for a particular
  * opal event. This should only be used by legacy devices which don't
  * have proper device tree bindings. Most devices should use
  * irq_of_parse_and_map() instead.
  */
 int opal_event_request(unsigned int opal_event_nr)
 {
 	if (WARN_ON_ONCE(!opal_event_irqchip.domain))
 		return NO_IRQ;

 	return irq_create_mapping(opal_event_irqchip.domain, opal_event_nr);
 }
 EXPORT_SYMBOL(opal_event_request);
	/*
	* This file implements an irqchip for OPAL events. Whenever there is
	* an interrupt that is handled by OPAL we get passed a list of events
	* that Linux needs to do something about. These basically look like
	* interrupts to Linux so we implement an irqchip to handle them.
	*
	* Copyright Alistair Popple, IBM Corporation 2014.
	*
	* 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/bitops.h>
	#include <linux/irq.h>
	#include <linux/irqchip.h>
	#include <linux/irqdomain.h>
	#include <linux/interrupt.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/platform_device.h>
	#include <linux/kthread.h>
	#include <linux/delay.h>
	#include <linux/slab.h>
	#include <linux/irq_work.h>

	#include <asm/machdep.h>
	#include <asm/opal.h>

	#include "powernv.h"

	/* Maximum number of events supported by OPAL firmware */
	#define MAX_NUM_EVENTS 64

	struct opal_event_irqchip {
	struct irq_chip irqchip;
	struct irq_domain *domain;
	unsigned long mask;
	};
	static struct opal_event_irqchip opal_event_irqchip;

	static unsigned int opal_irq_count;
	static unsigned int *opal_irqs;

	static void opal_handle_irq_work(struct irq_work *work);
	static u64 last_outstanding_events;
	static struct irq_work opal_event_irq_work = {
	.func = opal_handle_irq_work,
	};

	void opal_handle_events(uint64_t events)
	{
	int virq, hwirq = 0;
	u64 mask = opal_event_irqchip.mask;

	if (!in_irq() && (events & mask)) {
	last_outstanding_events = events;
	irq_work_queue(&opal_event_irq_work);
	return;
	}

	while (events & mask) {
	hwirq = fls64(events) - 1;
	if (BIT_ULL(hwirq) & mask) {
	virq = irq_find_mapping(opal_event_irqchip.domain,
	hwirq);
	if (virq)
	generic_handle_irq(virq);
	}
	events &= ~BIT_ULL(hwirq);
	}
	}

	static void opal_event_mask(struct irq_data *d)
	{
	clear_bit(d->hwirq, &opal_event_irqchip.mask);
	}

	static void opal_event_unmask(struct irq_data *d)
	{
	__be64 events;

	set_bit(d->hwirq, &opal_event_irqchip.mask);

	opal_poll_events(&events);
	last_outstanding_events = be64_to_cpu(events);

	/*
	* We can't just handle the events now with opal_handle_events().
	* If we did we would deadlock when opal_event_unmask() is called from
	* handle_level_irq() with the irq descriptor lock held, because
	* calling opal_handle_events() would call generic_handle_irq() and
	* then handle_level_irq() which would try to take the descriptor lock
	* again. Instead queue the events for later.
	*/
	if (last_outstanding_events & opal_event_irqchip.mask)
	/* Need to retrigger the interrupt */
	irq_work_queue(&opal_event_irq_work);
	}

	static int opal_event_set_type(struct irq_data *d, unsigned int flow_type)
	{
	/*
	* For now we only support level triggered events. The irq
	* handler will be called continuously until the event has
	* been cleared in OPAL.
	*/
	if (flow_type != IRQ_TYPE_LEVEL_HIGH)
	return -EINVAL;

	return 0;
	}

	static struct opal_event_irqchip opal_event_irqchip = {
	.irqchip = {
	.name = "OPAL EVT",
	.irq_mask = opal_event_mask,
	.irq_unmask = opal_event_unmask,
	.irq_set_type = opal_event_set_type,
	},
	.mask = 0,
	};

	static int opal_event_map(struct irq_domain *d, unsigned int irq,
	irq_hw_number_t hwirq)
	{
	irq_set_chip_data(irq, &opal_event_irqchip);
	irq_set_chip_and_handler(irq, &opal_event_irqchip.irqchip,
	handle_level_irq);

	return 0;
	}

	static irqreturn_t opal_interrupt(int irq, void *data)
	{
	__be64 events;

	opal_handle_interrupt(virq_to_hw(irq), &events);
	opal_handle_events(be64_to_cpu(events));

	return IRQ_HANDLED;
	}

	static void opal_handle_irq_work(struct irq_work *work)
	{
	opal_handle_events(last_outstanding_events);
	}

	static int opal_event_match(struct irq_domain h, struct device_node node,
	enum irq_domain_bus_token bus_token)
	{
	return irq_domain_get_of_node(h) == node;
	}

	static int opal_event_xlate(struct irq_domain h, struct device_node np,
	const u32 *intspec, unsigned int intsize,
	irq_hw_number_t out_hwirq, unsigned int out_flags)
	{
	*out_hwirq = intspec[0];
	*out_flags = IRQ_TYPE_LEVEL_HIGH;

	return 0;
	}

	static const struct irq_domain_ops opal_event_domain_ops = {
	.match = opal_event_match,
	.map = opal_event_map,
	.xlate = opal_event_xlate,
	};

	void opal_event_shutdown(void)
	{
	unsigned int i;

	/* First free interrupts, which will also mask them */
	for (i = 0; i < opal_irq_count; i++) {
	if (opal_irqs[i])
	free_irq(opal_irqs[i], NULL);
	opal_irqs[i] = 0;
	}
	}

	int __init opal_event_init(void)
	{
	struct device_node dn, opal_node;
	const __be32 *irqs;
	int i, irqlen, rc = 0;

	opal_node = of_find_node_by_path("/ibm,opal");
	if (!opal_node) {
	pr_warn("opal: Node not found\n");
	return -ENODEV;
	}

	/* If dn is NULL it means the domain won't be linked to a DT
	* node so therefore irq_of_parse_and_map(...) wont work. But
	* that shouldn't be problem because if we're running a
	* version of skiboot that doesn't have the dn then the
	* devices won't have the correct properties and will have to
	* fall back to the legacy method (opal_event_request(...))
	* anyway. */
	dn = of_find_compatible_node(NULL, NULL, "ibm,opal-event");
	opal_event_irqchip.domain = irq_domain_add_linear(dn, MAX_NUM_EVENTS,
	&opal_event_domain_ops, &opal_event_irqchip);
	of_node_put(dn);
	if (!opal_event_irqchip.domain) {
	pr_warn("opal: Unable to create irq domain\n");
	rc = -ENOMEM;
	goto out;
	}

	/* Get interrupt property */
	irqs = of_get_property(opal_node, "opal-interrupts", &irqlen);
	opal_irq_count = irqs ? (irqlen / 4) : 0;
	pr_debug("Found %d interrupts reserved for OPAL\n", opal_irq_count);

	/* Install interrupt handlers */
	opal_irqs = kcalloc(opal_irq_count, sizeof(*opal_irqs), GFP_KERNEL);
	for (i = 0; irqs && i < opal_irq_count; i++, irqs++) {
	unsigned int irq, virq;

	/* Get hardware and virtual IRQ */
	irq = be32_to_cpup(irqs);
	virq = irq_create_mapping(NULL, irq);
	if (virq == NO_IRQ) {
	pr_warn("Failed to map irq 0x%x\n", irq);
	continue;
	}

	/* Install interrupt handler */
	rc = request_irq(virq, opal_interrupt, 0, "opal", NULL);
	if (rc) {
	irq_dispose_mapping(virq);
	pr_warn("Error %d requesting irq %d (0x%x)\n",
	rc, virq, irq);
	continue;
	}

	/* Cache IRQ */
	opal_irqs[i] = virq;
	}

	out:
	of_node_put(opal_node);
	return rc;
	}
	machine_arch_initcall(powernv, opal_event_init);

	/**
	* opal_event_request(unsigned int opal_event_nr) - Request an event
	* @opal_event_nr: the opal event number to request
	*
	* This routine can be used to find the linux virq number which can
	* then be passed to request_irq to assign a handler for a particular
	* opal event. This should only be used by legacy devices which don't
	* have proper device tree bindings. Most devices should use
	* irq_of_parse_and_map() instead.
	*/
	int opal_event_request(unsigned int opal_event_nr)
	{
	if (WARN_ON_ONCE(!opal_event_irqchip.domain))
	return NO_IRQ;

	return irq_create_mapping(opal_event_irqchip.domain, opal_event_nr);
	}
	EXPORT_SYMBOL(opal_event_request);