genirq/irqdomain: Allow irq domain aliasing

It is not uncommon (at least with the ARM stuff) to have a piece
of hardware that implements different flavours of "interrupts".
A typical example of this is the GICv3 ITS, which implements
standard PCI/MSI support, but also some form of "generic MSI".

So far, the PCI/MSI domain is registered using the ITS device_node,
so that irq_find_host can return it. On the contrary, the raw MSI
domain is not registered with an device_node, making it impossible
to be looked up by another subsystem (obviously, using the same
device_node twice would only result in confusion, as it is not
defined which one irq_find_host would return).

A solution to this is to "type" domains that may be aliasing, and
to be able to lookup an device_node that matches a given type.
For this, we introduce irq_find_matching_host() as a superset
of irq_find_host:

struct irq_domain *irq_find_matching_host(struct device_node *node,
                                enum irq_domain_bus_token bus_token);

where bus_token is the "type" we want to match the domain against
(so far, only DOMAIN_BUS_ANY is defined). This result in some
moderately invasive changes on the PPC side (which is the only
user of the .match method).

This has otherwise no functionnal change.

Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: <linux-arm-kernel@lists.infradead.org>
Cc: Yijing Wang <wangyijing@huawei.com>
Cc: Ma Jun <majun258@huawei.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Duc Dang <dhdang@apm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Link: http://lkml.kernel.org/r/1438091186-10244-2-git-send-email-marc.zyngier@arm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
(cherry picked from commit ad3aedfbb04b3a2af54473cfe31f13953cfe9d84)
Signed-off-by: Alex Shi <alex.shi@linaro.org>

 Conflicts:
	add arch/powerpc/platforms/powernv/opal-irqchip.c
diff --git a/arch/powerpc/platforms/512x/mpc5121_ads_cpld.c b/arch/powerpc/platforms/512x/mpc5121_ads_cpld.c
index ca3a062..11090ab 100644
--- a/arch/powerpc/platforms/512x/mpc5121_ads_cpld.c
+++ b/arch/powerpc/platforms/512x/mpc5121_ads_cpld.c
@@ -123,7 +123,8 @@
 }
 
 static int
-cpld_pic_host_match(struct irq_domain *h, struct device_node *node)
+cpld_pic_host_match(struct irq_domain *h, struct device_node *node,
+		    enum irq_domain_bus_token bus_token)
 {
 	return cpld_pic_node == node;
 }
diff --git a/arch/powerpc/platforms/cell/interrupt.c b/arch/powerpc/platforms/cell/interrupt.c
index 3af8324..a15f1ef 100644
--- a/arch/powerpc/platforms/cell/interrupt.c
+++ b/arch/powerpc/platforms/cell/interrupt.c
@@ -222,7 +222,8 @@
 #endif /* CONFIG_SMP */
 
 
-static int iic_host_match(struct irq_domain *h, struct device_node *node)
+static int iic_host_match(struct irq_domain *h, struct device_node *node,
+			  enum irq_domain_bus_token bus_token)
 {
 	return of_device_is_compatible(node,
 				    "IBM,CBEA-Internal-Interrupt-Controller");
diff --git a/arch/powerpc/platforms/embedded6xx/flipper-pic.c b/arch/powerpc/platforms/embedded6xx/flipper-pic.c
index 4cde8e7..b7866e0 100644
--- a/arch/powerpc/platforms/embedded6xx/flipper-pic.c
+++ b/arch/powerpc/platforms/embedded6xx/flipper-pic.c
@@ -108,7 +108,8 @@
 	return 0;
 }
 
-static int flipper_pic_match(struct irq_domain *h, struct device_node *np)
+static int flipper_pic_match(struct irq_domain *h, struct device_node *np,
+			     enum irq_domain_bus_token bus_token)
 {
 	return 1;
 }
diff --git a/arch/powerpc/platforms/powermac/pic.c b/arch/powerpc/platforms/powermac/pic.c
index 59cfc9d..6f4f8b0 100644
--- a/arch/powerpc/platforms/powermac/pic.c
+++ b/arch/powerpc/platforms/powermac/pic.c
@@ -268,7 +268,8 @@
 	.name		= "cascade",
 };
 
-static int pmac_pic_host_match(struct irq_domain *h, struct device_node *node)
+static int pmac_pic_host_match(struct irq_domain *h, struct device_node *node,
+			       enum irq_domain_bus_token bus_token)
 {
 	/* We match all, we don't always have a node anyway */
 	return 1;
diff --git a/arch/powerpc/platforms/powernv/opal-irqchip.c b/arch/powerpc/platforms/powernv/opal-irqchip.c
new file mode 100644
index 0000000..2c91ee7
--- /dev/null
+++ b/arch/powerpc/platforms/powernv/opal-irqchip.c
@@ -0,0 +1,254 @@
+/*
+ * 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 __be64 last_outstanding_events;
+static struct irq_work opal_event_irq_work = {
+	.func = opal_handle_irq_work,
+};
+
+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)
+{
+	set_bit(d->hwirq, &opal_event_irqchip.mask);
+
+	opal_poll_events(&last_outstanding_events);
+	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;
+}
+
+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 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(be64_to_cpu(last_outstanding_events));
+}
+
+static int opal_event_match(struct irq_domain *h, struct device_node *node,
+			    enum irq_domain_bus_token bus_token)
+{
+	return h->of_node == 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);
diff --git a/arch/powerpc/platforms/ps3/interrupt.c b/arch/powerpc/platforms/ps3/interrupt.c
index a6c42f3..638c406 100644
--- a/arch/powerpc/platforms/ps3/interrupt.c
+++ b/arch/powerpc/platforms/ps3/interrupt.c
@@ -678,7 +678,8 @@
 	return 0;
 }
 
-static int ps3_host_match(struct irq_domain *h, struct device_node *np)
+static int ps3_host_match(struct irq_domain *h, struct device_node *np,
+			  enum irq_domain_bus_token bus_token)
 {
 	/* Match all */
 	return 1;
diff --git a/arch/powerpc/sysdev/ehv_pic.c b/arch/powerpc/sysdev/ehv_pic.c
index 2d20f10..eca0b00 100644
--- a/arch/powerpc/sysdev/ehv_pic.c
+++ b/arch/powerpc/sysdev/ehv_pic.c
@@ -177,7 +177,8 @@
 	return irq_linear_revmap(global_ehv_pic->irqhost, irq);
 }
 
-static int ehv_pic_host_match(struct irq_domain *h, struct device_node *node)
+static int ehv_pic_host_match(struct irq_domain *h, struct device_node *node,
+			      enum irq_domain_bus_token bus_token)
 {
 	/* Exact match, unless ehv_pic node is NULL */
 	return h->of_node == NULL || h->of_node == node;
diff --git a/arch/powerpc/sysdev/i8259.c b/arch/powerpc/sysdev/i8259.c
index 45598da..8c3756c 100644
--- a/arch/powerpc/sysdev/i8259.c
+++ b/arch/powerpc/sysdev/i8259.c
@@ -162,7 +162,8 @@
 	.flags = IORESOURCE_BUSY,
 };
 
-static int i8259_host_match(struct irq_domain *h, struct device_node *node)
+static int i8259_host_match(struct irq_domain *h, struct device_node *node,
+			    enum irq_domain_bus_token bus_token)
 {
 	return h->of_node == NULL || h->of_node == node;
 }
diff --git a/arch/powerpc/sysdev/ipic.c b/arch/powerpc/sysdev/ipic.c
index b287337..27d317a 100644
--- a/arch/powerpc/sysdev/ipic.c
+++ b/arch/powerpc/sysdev/ipic.c
@@ -671,7 +671,8 @@
 	.irq_set_type	= ipic_set_irq_type,
 };
 
-static int ipic_host_match(struct irq_domain *h, struct device_node *node)
+static int ipic_host_match(struct irq_domain *h, struct device_node *node,
+			   enum irq_domain_bus_token bus_token)
 {
 	/* Exact match, unless ipic node is NULL */
 	return h->of_node == NULL || h->of_node == node;
diff --git a/arch/powerpc/sysdev/mpic.c b/arch/powerpc/sysdev/mpic.c
index b2b8447..8b6e282 100644
--- a/arch/powerpc/sysdev/mpic.c
+++ b/arch/powerpc/sysdev/mpic.c
@@ -1007,7 +1007,8 @@
 #endif /* CONFIG_MPIC_U3_HT_IRQS */
 
 
-static int mpic_host_match(struct irq_domain *h, struct device_node *node)
+static int mpic_host_match(struct irq_domain *h, struct device_node *node,
+			   enum irq_domain_bus_token bus_token)
 {
 	/* Exact match, unless mpic node is NULL */
 	return h->of_node == NULL || h->of_node == node;
diff --git a/arch/powerpc/sysdev/qe_lib/qe_ic.c b/arch/powerpc/sysdev/qe_lib/qe_ic.c
index 543765e..da00c9e 100644
--- a/arch/powerpc/sysdev/qe_lib/qe_ic.c
+++ b/arch/powerpc/sysdev/qe_lib/qe_ic.c
@@ -244,7 +244,8 @@
 	.irq_mask_ack = qe_ic_mask_irq,
 };
 
-static int qe_ic_host_match(struct irq_domain *h, struct device_node *node)
+static int qe_ic_host_match(struct irq_domain *h, struct device_node *node,
+			    enum irq_domain_bus_token bus_token)
 {
 	/* Exact match, unless qe_ic node is NULL */
 	return h->of_node == NULL || h->of_node == node;
diff --git a/arch/powerpc/sysdev/xics/xics-common.c b/arch/powerpc/sysdev/xics/xics-common.c
index 878a540..41e334d 100644
--- a/arch/powerpc/sysdev/xics/xics-common.c
+++ b/arch/powerpc/sysdev/xics/xics-common.c
@@ -298,7 +298,8 @@
 }
 #endif /* CONFIG_SMP */
 
-static int xics_host_match(struct irq_domain *h, struct device_node *node)
+static int xics_host_match(struct irq_domain *h, struct device_node *node,
+			   enum irq_domain_bus_token bus_token)
 {
 	struct ics *ics;