irq: add irq_domain translation infrastructure

This patch adds irq_domain infrastructure for translating from
hardware irq numbers to linux irqs.  This is particularly important
for architectures adding device tree support because the current
implementation (excluding PowerPC and SPARC) cannot handle
translation for more than a single interrupt controller.  irq_domain
supports device tree translation for any number of interrupt
controllers.

This patch converts x86, Microblaze, ARM and MIPS to use irq_domain
for device tree irq translation.  x86 is untested beyond compiling it,
irq_domain is enabled for MIPS and Microblaze, but the old behaviour is
preserved until the core code is modified to actually register an
irq_domain yet.  On ARM it works and is required for much of the new
ARM device tree board support.

PowerPC has /not/ been converted to use this new infrastructure.  It
is still missing some features before it can replace the virq
infrastructure already in powerpc (see documentation on
irq_domain_map/unmap for details).  Followup patches will add the
missing pieces and migrate PowerPC to use irq_domain.

SPARC has its own method of managing interrupts from the device tree
and is unaffected by this change.

Acked-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

10 files changed, 36 insertions, 143 deletions

diff --git a/arch/arm/include/asm/prom.h b/arch/arm/include/asm/prom.h
index 11b8708fc4d..6f65ca86a5e 100644
--- a/arch/arm/include/asm/prom.h
+++ b/arch/arm/include/asm/prom.h
@@ -16,11 +16,6 @@
 #include <asm/setup.h>
 #include <asm/irq.h>
 
-static inline void irq_dispose_mapping(unsigned int virq)
-{
-	return;
-}
-
 extern struct machine_desc *setup_machine_fdt(unsigned int dt_phys);
 extern void arm_dt_memblock_reserve(void);
 
diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c
index 0cdd7b456cb..1a33e9d6bb1 100644
--- a/arch/arm/kernel/devtree.c
+++ b/arch/arm/kernel/devtree.c
@@ -132,17 +132,3 @@ struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys)
 
 	return mdesc_best;
 }
-
-/**
- * irq_create_of_mapping - Hook to resolve OF irq specifier into a Linux irq#
- *
- * Currently the mapping mechanism is trivial; simple flat hwirq numbers are
- * mapped 1:1 onto Linux irq numbers.  Cascaded irq controllers are not
- * supported.
- */
-unsigned int irq_create_of_mapping(struct device_node *controller,
-				   const u32 *intspec, unsigned int intsize)
-{
-	return intspec[0];
-}
-EXPORT_SYMBOL_GPL(irq_create_of_mapping);
diff --git a/arch/microblaze/include/asm/irq.h b/arch/microblaze/include/asm/irq.h
index cc54187f3d3..6a6d83bfc1a 100644
--- a/arch/microblaze/include/asm/irq.h
+++ b/arch/microblaze/include/asm/irq.h
@@ -16,6 +16,7 @@
  * be big enough to enclose whatever representation is used by a given
  * platform.
  */
+#define _IRQ_HW_NUMBER_T
 typedef unsigned long irq_hw_number_t;
 
 extern unsigned int nr_irq;
@@ -25,15 +26,6 @@ extern unsigned int nr_irq;
 struct pt_regs;
 extern void do_IRQ(struct pt_regs *regs);
 
-/** FIXME - not implement
- * irq_dispose_mapping - Unmap an interrupt
- * @virq: linux virq number of the interrupt to unmap
- */
-static inline void irq_dispose_mapping(unsigned int virq)
-{
-	return;
-}
-
 struct irq_host;
 
 /**
diff --git a/arch/microblaze/kernel/irq.c b/arch/microblaze/kernel/irq.c
index ce7ac8435d5..59bb560018e 100644
--- a/arch/microblaze/kernel/irq.c
+++ b/arch/microblaze/kernel/irq.c
@@ -54,10 +54,3 @@ unsigned int irq_create_mapping(struct irq_host *host, irq_hw_number_t hwirq)
 	return hwirq;
 }
 EXPORT_SYMBOL_GPL(irq_create_mapping);
-
-unsigned int irq_create_of_mapping(struct device_node *controller,
-				   const u32 *intspec, unsigned int intsize)
-{
-	return intspec[0];
-}
-EXPORT_SYMBOL_GPL(irq_create_of_mapping);
diff --git a/arch/mips/include/asm/irq.h b/arch/mips/include/asm/irq.h
index 0ec01294b06..dc650aeac78 100644
--- a/arch/mips/include/asm/irq.h
+++ b/arch/mips/include/asm/irq.h
@@ -16,11 +16,6 @@
 
 #include <irq.h>
 
-static inline void irq_dispose_mapping(unsigned int virq)
-{
-	return;
-}
-
 #ifdef CONFIG_I8259
 static inline int irq_canonicalize(int irq)
 {
diff --git a/arch/mips/kernel/prom.c b/arch/mips/kernel/prom.c
index 5b7eade41fa..010aaaf2278 100644
--- a/arch/mips/kernel/prom.c
+++ b/arch/mips/kernel/prom.c
@@ -60,20 +60,6 @@ void __init early_init_dt_setup_initrd_arch(unsigned long start,
 }
 #endif
 
-/*
- * irq_create_of_mapping - Hook to resolve OF irq specifier into a Linux irq#
- *
- * Currently the mapping mechanism is trivial; simple flat hwirq numbers are
- * mapped 1:1 onto Linux irq numbers.  Cascaded irq controllers are not
- * supported.
- */
-unsigned int irq_create_of_mapping(struct device_node *controller,
-				   const u32 *intspec, unsigned int intsize)
-{
-	return intspec[0];
-}
-EXPORT_SYMBOL_GPL(irq_create_of_mapping);
-
 void __init early_init_devtree(void *params)
 {
 	/* Setup flat device-tree pointer */
diff --git a/arch/powerpc/include/asm/irq.h b/arch/powerpc/include/asm/irq.h
index 1bff591f7f7..66bf09e21cb 100644
--- a/arch/powerpc/include/asm/irq.h
+++ b/arch/powerpc/include/asm/irq.h
@@ -45,6 +45,7 @@ extern atomic_t ppc_n_lost_interrupts;
  * be big enough to enclose whatever representation is used by a given
  * platform.
  */
+#define _IRQ_HW_NUMBER_T
 typedef unsigned long irq_hw_number_t;
 
 /* Interrupt controller "host" data structure. This could be defined as a
diff --git a/arch/x86/include/asm/irq_controller.h b/arch/x86/include/asm/irq_controller.h
deleted file mode 100644
index 423bbbddf36..00000000000
--- a/arch/x86/include/asm/irq_controller.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef __IRQ_CONTROLLER__
-#define __IRQ_CONTROLLER__
-
-struct irq_domain {
-	int (*xlate)(struct irq_domain *h, const u32 *intspec, u32 intsize,
-			u32 *out_hwirq, u32 *out_type);
-	void *priv;
-	struct device_node *controller;
-	struct list_head l;
-};
-
-#endif
diff --git a/arch/x86/include/asm/prom.h b/arch/x86/include/asm/prom.h
index 971e0b46446..2c8101e9279 100644
--- a/arch/x86/include/asm/prom.h
+++ b/arch/x86/include/asm/prom.h
@@ -21,7 +21,6 @@
 #include <asm/irq.h>
 #include <asm/atomic.h>
 #include <asm/setup.h>
-#include <asm/irq_controller.h>
 
 #ifdef CONFIG_OF
 extern int of_ioapic;
@@ -54,15 +53,6 @@ extern char cmd_line[COMMAND_LINE_SIZE];
 #define pci_address_to_pio pci_address_to_pio
 unsigned long pci_address_to_pio(phys_addr_t addr);
 
-/**
- * irq_dispose_mapping - Unmap an interrupt
- * @virq: linux virq number of the interrupt to unmap
- *
- * FIXME: We really should implement proper virq handling like power,
- * but that's going to be major surgery.
- */
-static inline void irq_dispose_mapping(unsigned int virq) { }
-
 #define HAVE_ARCH_DEVTREE_FIXUPS
 
 #endif /* __ASSEMBLY__ */
diff --git a/arch/x86/kernel/devicetree.c b/arch/x86/kernel/devicetree.c
index 9aeb78a23de..250c2d583f6 100644
--- a/arch/x86/kernel/devicetree.c
+++ b/arch/x86/kernel/devicetree.c
@@ -16,64 +16,14 @@
 #include <linux/initrd.h>
 
 #include <asm/hpet.h>
-#include <asm/irq_controller.h>
 #include <asm/apic.h>
 #include <asm/pci_x86.h>
 
 __initdata u64 initial_dtb;
 char __initdata cmd_line[COMMAND_LINE_SIZE];
-static LIST_HEAD(irq_domains);
-static DEFINE_RAW_SPINLOCK(big_irq_lock);
 
 int __initdata of_ioapic;
 
-#ifdef CONFIG_X86_IO_APIC
-static void add_interrupt_host(struct irq_domain *ih)
-{
-	unsigned long flags;
-
-	raw_spin_lock_irqsave(&big_irq_lock, flags);
-	list_add(&ih->l, &irq_domains);
-	raw_spin_unlock_irqrestore(&big_irq_lock, flags);
-}
-#endif
-
-static struct irq_domain *get_ih_from_node(struct device_node *controller)
-{
-	struct irq_domain *ih, *found = NULL;
-	unsigned long flags;
-
-	raw_spin_lock_irqsave(&big_irq_lock, flags);
-	list_for_each_entry(ih, &irq_domains, l) {
-		if (ih->controller ==  controller) {
-			found = ih;
-			break;
-		}
-	}
-	raw_spin_unlock_irqrestore(&big_irq_lock, flags);
-	return found;
-}
-
-unsigned int irq_create_of_mapping(struct device_node *controller,
-				   const u32 *intspec, unsigned int intsize)
-{
-	struct irq_domain *ih;
-	u32 virq, type;
-	int ret;
-
-	ih = get_ih_from_node(controller);
-	if (!ih)
-		return 0;
-	ret = ih->xlate(ih, intspec, intsize, &virq, &type);
-	if (ret)
-		return 0;
-	if (type == IRQ_TYPE_NONE)
-		return virq;
-	irq_set_irq_type(virq, type);
-	return virq;
-}
-EXPORT_SYMBOL_GPL(irq_create_of_mapping);
-
 unsigned long pci_address_to_pio(phys_addr_t address)
 {
 	/*
@@ -377,36 +327,49 @@ static struct of_ioapic_type of_ioapic_type[] =
 	},
 };
 
-static int ioapic_xlate(struct irq_domain *id, const u32 *intspec, u32 intsize,
-			u32 *out_hwirq, u32 *out_type)
+static int ioapic_dt_translate(struct irq_domain *domain,
+				struct device_node *controller,
+				const u32 *intspec, u32 intsize,
+				irq_hw_number_t *out_hwirq, u32 *out_type)
 {
-	struct mp_ioapic_gsi *gsi_cfg;
 	struct io_apic_irq_attr attr;
 	struct of_ioapic_type *it;
 	u32 line, idx, type;
+	int rc;
 
-	if (intsize < 2)
+	if (controller != domain->of_node)
 		return -EINVAL;
 
-	line = *intspec;
-	idx = (u32) id->priv;
-	gsi_cfg = mp_ioapic_gsi_routing(idx);
-	*out_hwirq = line + gsi_cfg->gsi_base;
+	if (intsize < 2)
+		return -EINVAL;
 
-	intspec++;
-	type = *intspec;
+	line = intspec[0];
 
-	if (type >= ARRAY_SIZE(of_ioapic_type))
+	if (intspec[1] >= ARRAY_SIZE(of_ioapic_type))
 		return -EINVAL;
 
-	it = of_ioapic_type + type;
-	*out_type = it->out_type;
+	it = of_ioapic_type + intspec[1];
+	type = it->out_type;
 
+	idx = (u32) domain->priv;
 	set_io_apic_irq_attr(&attr, idx, line, it->trigger, it->polarity);
 
-	return io_apic_setup_irq_pin_once(*out_hwirq, cpu_to_node(0), &attr);
+	rc = io_apic_setup_irq_pin_once(irq_domain_to_irq(domain, line),
+					cpu_to_node(0), &attr);
+	if (rc)
+		return rc;
+
+	if (out_hwirq)
+		*out_hwirq = line;
+	if (out_type)
+		*out_type = type;
+	return 0;
 }
 
+const struct irq_domain_ops ioapic_irq_domain_ops = {
+	.dt_translate = ioapic_dt_translate,
+};
+
 static void __init ioapic_add_ofnode(struct device_node *np)
 {
 	struct resource r;
@@ -422,13 +385,17 @@ static void __init ioapic_add_ofnode(struct device_node *np)
 	for (i = 0; i < nr_ioapics; i++) {
 		if (r.start == mpc_ioapic_addr(i)) {
 			struct irq_domain *id;
+			struct mp_ioapic_gsi *gsi_cfg;
+
+			gsi_cfg = mp_ioapic_gsi_routing(i);
 
 			id = kzalloc(sizeof(*id), GFP_KERNEL);
 			BUG_ON(!id);
-			id->controller = np;
-			id->xlate = ioapic_xlate;
+			id->ops = &ioapic_irq_domain_ops;
+			id->irq_base = gsi_cfg->gsi_base;
+			id->of_node = np;
 			id->priv = (void *)i;
-			add_interrupt_host(id);
+			irq_domain_add(id);
 			return;
 		}
 	}