Re: [PATCH v3 3/7] irqchip: gic: Support hierarchy irq domain.

[Marc Zyngier <marc.zyngier@arm.com>]

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On 13/10/14 11:43, Joe.C wrote:
> On Thu, 2014-10-09 at 17:59 +0100, Marc Zyngier wrote:
>> On 09/10/14 15:29, Joe.C wrote
>>> @@ -952,7 +988,11 @@ void __init gic_init_bases(unsigned int gic_nr, int irq_start,
>>>  
>>>  	gic_irqs -= hwirq_base; /* calculate # of irqs to allocate */
>>>  
>>> -	if (of_property_read_u32(node, "arm,routable-irqs",
>>> +	if (IS_ENABLED(CONFIG_IRQ_DOMAIN_HIERARCHY) &&
>>> +		of_find_property(node, "arm,irq-domain-hierarchy", NULL))
>>> +		gic->domain = irq_domain_add_linear(node, gic_irqs,
>>> +					&gic_irq_domain_hierarchy_ops, gic);
>>
>> I really think that looking for a property is the wrong thing to do. If
>> "node" is non-NULL, then we're pretty sure that we're initializing from
>> DT, and that a pure linear domain should be the right thing, leaving the
>> legacy stuff for the few non-DT platforms that are still around.
>>
>> Thanks,
>>
>> 	M.
> 
> The only reason I introduce "arm,irq-domain-hierarchy" property is
> trying to keep original behavior when hierarchy irq domain is not used.
> Without this, when a board init GIC with DT, all driver will have to use
> devicetree. I'm not sure we want to break things like this.

I don't think we want to support a "middle of the road" setup, where the
GIC is probed by DT, but some devices have hardcoded interrupts.

> I will remove this and just use linear for all DT in my next version.

I came up with the attached patch, which allows me to boot my test
platform (together with the other fix I posted earlier).

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...

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>From 97d4ea1f0922fb47dd1b09cd2694b7fa5b519db9 Mon Sep 17 00:00:00 2001
From: Marc Zyngier <marc.zyngier@arm.com>
Date: Mon, 13 Oct 2014 10:57:28 +0100
Subject: [PATCH] fixup! irqchip: gic: Support hierarchy irq domain.

---
 drivers/irqchip/Kconfig   |  1 +
 drivers/irqchip/irq-gic.c | 53 ++++++++++++++++++++++-------------------------
 2 files changed, 26 insertions(+), 28 deletions(-)

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index b8632bf..2a48e0a 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -5,6 +5,7 @@ config IRQCHIP
 config ARM_GIC
 	bool
 	select IRQ_DOMAIN
+	select IRQ_DOMAIN_HIERARCHY
 	select MULTI_IRQ_HANDLER
 
 config GIC_NON_BANKED
diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
index 17f5aa6..a99c211 100644
--- a/drivers/irqchip/irq-gic.c
+++ b/drivers/irqchip/irq-gic.c
@@ -835,8 +835,6 @@ static struct notifier_block gic_cpu_notifier = {
 };
 #endif
 
-
-#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
 static int gic_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
 				unsigned int nr_irqs, void *arg)
 {
@@ -870,10 +868,8 @@ static void gic_irq_domain_free(struct irq_domain *domain, unsigned int virq,
 static const struct irq_domain_ops gic_irq_domain_hierarchy_ops = {
 	.alloc = gic_irq_domain_alloc,
 	.free = gic_irq_domain_free,
+	.xlate = gic_irq_domain_xlate,
 };
-#else
-#define gic_irq_domain_hierarchy_ops 0
-#endif /* CONFIG_IRQ_DOMAIN_HIERARCHY */
 
 static const struct irq_domain_ops gic_irq_domain_ops = {
 	.map = gic_irq_domain_map,
@@ -965,18 +961,6 @@ void __init gic_init_bases(unsigned int gic_nr, int irq_start,
 		gic_cpu_map[i] = 0xff;
 
 	/*
-	 * For primary GICs, skip over SGIs.
-	 * For secondary GICs, skip over PPIs, too.
-	 */
-	if (gic_nr == 0 && (irq_start & 31) > 0) {
-		hwirq_base = 16;
-		if (irq_start != -1)
-			irq_start = (irq_start & ~31) + 16;
-	} else {
-		hwirq_base = 32;
-	}
-
-	/*
 	 * Find out how many interrupts are supported.
 	 * The GIC only supports up to 1020 interrupt sources.
 	 */
@@ -986,14 +970,31 @@ void __init gic_init_bases(unsigned int gic_nr, int irq_start,
 		gic_irqs = 1020;
 	gic->gic_irqs = gic_irqs;
 
-	gic_irqs -= hwirq_base; /* calculate # of irqs to allocate */
+	if (node) {		/* DT case */
+		const struct irq_domain_ops *ops = &gic_irq_domain_hierarchy_ops;
+
+		if (!of_property_read_u32(node, "arm,routable-irqs",
+					  &nr_routable_irqs)) {
+			ops = &gic_irq_domain_ops;
+			gic_irqs = nr_routable_irqs;
+		}
+
+		gic->domain = irq_domain_add_linear(node, gic_irqs, ops, gic);
+	} else {		/* Non-DT case */
+		/*
+		 * For primary GICs, skip over SGIs.
+		 * For secondary GICs, skip over PPIs, too.
+		 */
+		if (gic_nr == 0 && (irq_start & 31) > 0) {
+			hwirq_base = 16;
+			if (irq_start != -1)
+				irq_start = (irq_start & ~31) + 16;
+		} else {
+			hwirq_base = 32;
+		}
+
+		gic_irqs -= hwirq_base; /* calculate # of irqs to allocate */
 
-	if (IS_ENABLED(CONFIG_IRQ_DOMAIN_HIERARCHY) &&
-		of_find_property(node, "arm,irq-domain-hierarchy", NULL))
-		gic->domain = irq_domain_add_linear(node, gic_irqs,
-					&gic_irq_domain_hierarchy_ops, gic);
-	else if (of_property_read_u32(node, "arm,routable-irqs",
-				 &nr_routable_irqs)) {
 		irq_base = irq_alloc_descs(irq_start, 16, gic_irqs,
 					   numa_node_id());
 		if (IS_ERR_VALUE(irq_base)) {
@@ -1004,10 +1005,6 @@ void __init gic_init_bases(unsigned int gic_nr, int irq_start,
 
 		gic->domain = irq_domain_add_legacy(node, gic_irqs, irq_base,
 					hwirq_base, &gic_irq_domain_ops, gic);
-	} else {
-		gic->domain = irq_domain_add_linear(node, nr_routable_irqs,
-						    &gic_irq_domain_ops,
-						    gic);
 	}
 
 	if (WARN_ON(!gic->domain))
-- 
2.0.4