irqchip/mips-gic: Replace static map with dynamic

Commit 4cfffcfa ("irqchip/mips-gic: Fix local interrupts") fixed
local interrupts by creating virq mappings for them all at startup.
Unfortunately this change broke legacy IRQ controllers in the same
system, such as the i8259 on the Malta platform, as it allocates virq
numbers that were expected to be available for the legacy controller.

Instead of creating the mappings statically when the GIC is probed,
re-introduce the irq domain .map function, removed by commit e875bd66
("irqchip/mips-gic: Fix local interrupts") and use it to set up the irq
handler and chip. Since a good deal of the required functionality is
already implemented by gic_irq_domain_alloc, repurpose that function for
gic_irq_domain_map and add a new gic_irq_domain_alloc which wraps
gic_irq_domain_map with the necessary conversion.

This change fixes the legacy interrupt controller of the Malta platform
without breaking the perf interrupt fixed by commit e875bd66
("irqchip/mips-gic: Fix local interrupts").
Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Link: http://lkml.kernel.org/r/1492679256-14513-4-git-send-email-matt.redfearn@imgtec.comSigned-off-by: Thomas Gleixner <tglx@linutronix.de>

drivers/irqchip/irq-mips-gic.c

@@ -700,16 +700,12 @@ static int gic_irq_domain_xlate(struct irq_domain *d, struct device_node *ctrlr,
 	return 0;
 }
 
-static int gic_irq_domain_alloc(struct irq_domain *d, unsigned int virq,
-				unsigned int nr_irqs, void *arg)
+static int gic_irq_domain_map(struct irq_domain *d, unsigned int virq,
+			      irq_hw_number_t hwirq)
 {
-	struct irq_fwspec *fwspec = arg;
-	irq_hw_number_t hwirq;
 	int err;
 
-	if (fwspec->param[0] == GIC_SHARED) {
-		hwirq = GIC_SHARED_TO_HWIRQ(fwspec->param[1]);
-
+	if (hwirq >= GIC_SHARED_HWIRQ_BASE) {
 		/* verify that shared irqs don't conflict with an IPI irq */
 		if (test_bit(GIC_HWIRQ_TO_SHARED(hwirq), ipi_resrv))
 			return -EBUSY;
@@ -723,8 +719,6 @@ static int gic_irq_domain_alloc(struct irq_domain *d, unsigned int virq,
 		return gic_shared_irq_domain_map(d, virq, hwirq, 0);
 	}
 
-	hwirq = GIC_LOCAL_TO_HWIRQ(fwspec->param[1]);
-
 	switch (GIC_HWIRQ_TO_LOCAL(hwirq)) {
 	case GIC_LOCAL_INT_TIMER:
 	case GIC_LOCAL_INT_PERFCTR:
@@ -758,6 +752,20 @@ static int gic_irq_domain_alloc(struct irq_domain *d, unsigned int virq,
 	return gic_local_irq_domain_map(d, virq, hwirq);
 }
 
+static int gic_irq_domain_alloc(struct irq_domain *d, unsigned int virq,
+				unsigned int nr_irqs, void *arg)
+{
+	struct irq_fwspec *fwspec = arg;
+	irq_hw_number_t hwirq;
+
+	if (fwspec->param[0] == GIC_SHARED)
+		hwirq = GIC_SHARED_TO_HWIRQ(fwspec->param[1]);
+	else
+		hwirq = GIC_LOCAL_TO_HWIRQ(fwspec->param[1]);
+
+	return gic_irq_domain_map(d, virq, hwirq);
+}
+
 void gic_irq_domain_free(struct irq_domain *d, unsigned int virq,
 			 unsigned int nr_irqs)
 {
@@ -767,6 +775,7 @@ static const struct irq_domain_ops gic_irq_domain_ops = {
 	.xlate = gic_irq_domain_xlate,
 	.alloc = gic_irq_domain_alloc,
 	.free = gic_irq_domain_free,
+	.map = gic_irq_domain_map,
 };
 
 static int gic_ipi_domain_xlate(struct irq_domain *d, struct device_node *ctrlr,
@@ -872,38 +881,6 @@ static struct irq_domain_ops gic_ipi_domain_ops = {
 	.match = gic_ipi_domain_match,
 };
 
-static void __init gic_map_single_int(struct device_node *node,
-				      unsigned int irq)
-{
-	unsigned int linux_irq;
-	struct irq_fwspec local_int_fwspec = {
-		.fwnode         = &node->fwnode,
-		.param_count    = 3,
-		.param          = {
-			[0]     = GIC_LOCAL,
-			[1]     = irq,
-			[2]     = IRQ_TYPE_NONE,
-		},
-	};
-
-	if (!gic_local_irq_is_routable(irq))
-		return;
-
-	linux_irq = irq_create_fwspec_mapping(&local_int_fwspec);
-	WARN_ON(!linux_irq);
-}
-
-static void __init gic_map_interrupts(struct device_node *node)
-{
-	gic_map_single_int(node, GIC_LOCAL_INT_WD);
-	gic_map_single_int(node, GIC_LOCAL_INT_COMPARE);
-	gic_map_single_int(node, GIC_LOCAL_INT_TIMER);
-	gic_map_single_int(node, GIC_LOCAL_INT_PERFCTR);
-	gic_map_single_int(node, GIC_LOCAL_INT_SWINT0);
-	gic_map_single_int(node, GIC_LOCAL_INT_SWINT1);
-	gic_map_single_int(node, GIC_LOCAL_INT_FDC);
-}
-
 static void __init __gic_init(unsigned long gic_base_addr,
 			      unsigned long gic_addrspace_size,
 			      unsigned int cpu_vec, unsigned int irqbase,
@@ -997,7 +974,6 @@ static void __init __gic_init(unsigned long gic_base_addr,
 
 	bitmap_copy(ipi_available, ipi_resrv, GIC_MAX_INTRS);
 	gic_basic_init();
-	gic_map_interrupts(node);
 }
 
 void __init gic_init(unsigned long gic_base_addr,