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Subject[PATCH 3/3] ARM: gic: add OF based initialization
Date
From: Rob Herring <rob.herring@calxeda.com>

This adds ARM gic interrupt controller initialization using device tree
data.

The initialization function is intended to be called by of_irq_init
function like this:

const static struct of_device_id irq_match[] = {
{ .compatible = "arm,cortex-a9-gic", .data = gic_of_init, },
{}
};

static void __init init_irqs(void)
{
of_irq_init(irq_match);
}

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
---
Documentation/devicetree/bindings/arm/gic.txt | 55 +++++++++++++++
arch/arm/common/gic.c | 89 +++++++++++++++++++++++-
arch/arm/include/asm/hardware/gic.h | 12 ++++
3 files changed, 152 insertions(+), 4 deletions(-)
create mode 100644 Documentation/devicetree/bindings/arm/gic.txt

diff --git a/Documentation/devicetree/bindings/arm/gic.txt b/Documentation/devicetree/bindings/arm/gic.txt
new file mode 100644
index 0000000..52916b4
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/gic.txt
@@ -0,0 +1,55 @@
+* ARM Generic Interrupt Controller
+
+ARM SMP cores are often associated with a GIC, providing per processor
+interrupts (PPI), shared processor interrupts (SPI) and software
+generated interrupts (SGI).
+
+Primary GIC is attached directly to the CPU and typically has PPIs and SGIs.
+Secondary GICs are cascaded into the upward interrupt controller and do not
+have PPIs or SGIs.
+
+Main node required properties:
+
+- compatible : should be one of:
+ "arm,cortex-a9-gic"
+ "arm,arm11mp-gic"
+- interrupt-controller : Identifies the node as an interrupt controller
+- #interrupt-cells : Specifies the number of cells needed to encode an
+ interrupt source. The type shall be a <u32> and the value shall be 3.
+
+ The 1st cell is the interrupt type; 0 for SPI interrupts, 1 for PPI
+ interrupts.
+
+ The 2nd cell contains the interrupt number for the interrupt type.
+ SPI interrupts are in the range [0-987]. PPI interrupts are in the
+ range [0-15].
+
+ The 3rd cell is the flags, encoded as follows:
+ bits[3:0] trigger type and level flags.
+ 1 = low-to-high edge triggered
+ 2 = high-to-low edge triggered
+ 4 = active high level-sensitive
+ 8 = active low level-sensitive
+ bits[15:8] PPI interrupt cpu mask. Each bit corresponds to each of
+ the 8 possible cpus attached to the GIC. A bit set to '1' indicated
+ the interrupt is wired to that CPU. Only valid for PPI interrupts.
+
+- reg : Specifies base physical address(s) and size of the GIC registers. The
+ first region is the GIC distributor register base and size. The 2nd region is
+ the GIC cpu interface register base and size.
+
+Optional
+- interrupts : Interrupt source of the parent interrupt controller. Only
+ present on secondary GICs.
+
+Example:
+
+ intc: interrupt-controller@fff11000 {
+ compatible = "arm,cortex-a9-gic";
+ #interrupt-cells = <3>;
+ #address-cells = <1>;
+ interrupt-controller;
+ reg = <0xfff11000 0x1000>,
+ <0xfff10100 0x100>;
+ };
+
diff --git a/arch/arm/common/gic.c b/arch/arm/common/gic.c
index 666b278..84e69a4 100644
--- a/arch/arm/common/gic.c
+++ b/arch/arm/common/gic.c
@@ -28,6 +28,10 @@
#include <linux/smp.h>
#include <linux/cpumask.h>
#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/irqdomain.h>

#include <asm/irq.h>
#include <asm/mach/irq.h>
@@ -255,6 +259,15 @@ void __init gic_cascade_irq(unsigned int gic_nr, unsigned int irq)
irq_set_chained_handler(irq, gic_handle_cascade_irq);
}

+static int gic_irq_count(void __iomem *dist_base)
+{
+ int gic_irqs = readl_relaxed(dist_base + GIC_DIST_CTR) & 0x1f;
+ gic_irqs = (gic_irqs + 1) * 32;
+ if (gic_irqs > 1020)
+ gic_irqs = 1020;
+ return gic_irqs;
+}
+
static void __init gic_dist_init(struct gic_chip_data *gic,
unsigned int irq_start)
{
@@ -277,10 +290,7 @@ static void __init gic_dist_init(struct gic_chip_data *gic,
* Find out how many interrupts are supported.
* The GIC only supports up to 1020 interrupt sources.
*/
- gic_irqs = readl_relaxed(base + GIC_DIST_CTR) & 0x1f;
- gic_irqs = (gic_irqs + 1) * 32;
- if (gic_irqs > 1020)
- gic_irqs = 1020;
+ gic_irqs = gic_irq_count(base);

/*
* Set all global interrupts to be level triggered, active low.
@@ -405,3 +415,74 @@ void gic_raise_softirq(const struct cpumask *mask, unsigned int irq)
writel_relaxed(map << 16 | irq, gic_data[0].dist_base + GIC_DIST_SOFTINT);
}
#endif
+
+#ifdef CONFIG_OF
+static int gic_cnt __initdata = 0;
+
+int gic_irq_domain_dt_translate(struct irq_domain *d,
+ struct device_node *controller,
+ const u32 *intspec, unsigned int intsize,
+ unsigned long *out_hwirq, unsigned int *out_type)
+{
+ struct gic_chip_data *gic_data = d->priv;
+
+ if (d->of_node != controller)
+ return -EINVAL;
+ if (intsize < 3)
+ return -EINVAL;
+
+ *out_hwirq = intspec[1];
+ /*
+ * We've already skipped over SGIs, so PPIs need no translation.
+ * For SPIs, we need to skip over 16 PPIs on primary GICs.
+ */
+ if (!intspec[0] && !gic_data->irq_offset)
+ *out_hwirq += 16;
+
+ *out_type = intspec[2] & IRQ_TYPE_SENSE_MASK;
+ return 0;
+}
+
+struct irq_domain_ops gic_irq_domain_ops = {
+ .dt_translate = gic_irq_domain_dt_translate,
+};
+
+int __init gic_of_init(struct device_node *node, struct device_node *parent)
+{
+ void __iomem *cpu_base;
+ void __iomem *dist_base;
+ int irq;
+ struct irq_domain *domain = &gic_data[gic_cnt].domain;
+
+ if (WARN_ON(!node))
+ return -ENODEV;
+
+ dist_base = of_iomap(node, 0);
+ WARN(!dist_base, "unable to map gic dist registers\n");
+
+ cpu_base = of_iomap(node, 1);
+ WARN(!cpu_base, "unable to map gic cpu registers\n");
+
+ domain->nr_irq = gic_irq_count(dist_base);
+ /* subtract off SGIs. Also subtract off PPIs for secondary GICs */
+ if (parent)
+ domain->nr_irq -= 32;
+ else
+ domain->nr_irq -= 16;
+
+ domain->irq_base = irq_alloc_descs(-1, 16, domain->nr_irq, numa_node_id());
+ domain->of_node = of_node_get(node);
+ domain->ops = &gic_irq_domain_ops;
+ domain->priv = &gic_data[gic_cnt];
+ irq_domain_add(domain);
+
+ gic_init(gic_cnt, domain->irq_base, dist_base, cpu_base);
+
+ if (parent) {
+ irq = irq_of_parse_and_map(node, 0);
+ gic_cascade_irq(gic_cnt, irq);
+ }
+ gic_cnt++;
+ return 0;
+}
+#endif
diff --git a/arch/arm/include/asm/hardware/gic.h b/arch/arm/include/asm/hardware/gic.h
index 435d3f8..2862d0e 100644
--- a/arch/arm/include/asm/hardware/gic.h
+++ b/arch/arm/include/asm/hardware/gic.h
@@ -33,10 +33,21 @@
#define GIC_DIST_SOFTINT 0xf00

#ifndef __ASSEMBLY__
+#include <linux/irqdomain.h>
+
extern void __iomem *gic_cpu_base_addr;
extern struct irq_chip gic_arch_extn;

void gic_init(unsigned int, unsigned int, void __iomem *, void __iomem *);
+#ifdef CONFIG_OF
+int gic_of_init(struct device_node *node, struct device_node *parent);
+#else
+static inline void gic_of_init(struct device_node *node,
+ struct device_node *parent)
+{
+ return -ENODEV;
+}
+#endif
void gic_secondary_init(unsigned int);
void gic_cascade_irq(unsigned int gic_nr, unsigned int irq);
void gic_raise_softirq(const struct cpumask *mask, unsigned int irq);
@@ -46,6 +57,7 @@ struct gic_chip_data {
unsigned int irq_offset;
void __iomem *dist_base;
void __iomem *cpu_base;
+ struct irq_domain domain;
};
#endif

--
1.7.5.4


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