Add support for translation of hardware interrupt numbers specified in device
tree nodes to linux irq number.
Signed-off-by: Thomas Abraham <thomas.abraham@xxxxxxxxxx>
---
Notes:
1. The translation of SGI/PPI interrupts is supported only for CPU0.
2. The documentation is derived from the following patch submitted
earlier by Rob Herring.
[PATCH 2/3] ARM: gic: add OF based initialization
Documentation/devicetree/bindings/arm/gic.txt | 21 +++++++
arch/arm/common/gic.c | 70 +++++++++++++++++++++++++
2 files changed, 91 insertions(+), 0 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..3204ac5
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/gic.txt
@@ -0,0 +1,21 @@
+* ARM Generic Interrupt Controller
+
+Some ARM cores have an interrupt controller called GIC. The ARM GIC
+representation in the device tree should be done as under:
+
+Required properties:
+- compatible: should be "arm,cortex-a9-gic".
+- reg: Specifies base physical address(s) and size of the GIC registers. The
+ first two values are the GIC distributor register base and size. The second
+ two values are the GIC cpu interface register base and size.
+- interrupt-controller: Identifies the node as an interrupt controller
+- #interrupt-cells: Specifies the number of cells needed to encode a
+ interrupt source and the value shall be 1.
+
+Example:
+ GIC:interrupt-controller@10490000 {
+ compatible = "arm,cortex-a9-gic";
+ #interrupt-cells = <2>;
+ interrupt-controller;
+ reg = <0x10490000 0x1000>, <0x10480000 0x100>;
+ };
diff --git a/arch/arm/common/gic.c b/arch/arm/common/gic.c
index 3227ca9..c11d3a5 100644
--- a/arch/arm/common/gic.c
+++ b/arch/arm/common/gic.c
@@ -28,6 +28,11 @@
#include <linux/smp.h>
#include <linux/cpumask.h>
#include <linux/io.h>
+#ifdef CONFIG_OF_IRQ
+#include <linux/irqdomain.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+#endif
#include <asm/irq.h>
#include <asm/mach/irq.h>
@@ -394,3 +399,68 @@ 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_IRQ
+
+/* GIC interrupt types corresponding to the device tree interrupt specifier */
+enum gic_int_type {
+ GIC_INT_TYPE_SPI = 0,
+ GIC_INT_TYPE_SGI = 1,
+ GIC_INT_TYPE_PPI = 2,
+};
+
+/* Translate dt irq specifier to linux irq number */
+static int gic_irq_domain_translate_dt(struct irq_domain *d,
+ struct device_node *controller,
+ const u32 *intspec, unsigned int intsize,
+ unsigned long *out_hwirq, unsigned int *out_type)
+{
+ if (d->of_node != controller)
+ return -EINVAL;
+ if (intsize < 2)
+ return -EINVAL;
+
+ switch (intspec[0]) {
+ case GIC_INT_TYPE_SPI:
+ *out_hwirq = intspec[1] + 32; /* +32, for start of SPI */
+ break;
+ case GIC_INT_TYPE_SGI:
+ *out_hwirq = intspec[1];
+ break;
+ case GIC_INT_TYPE_PPI:
+ *out_hwirq = intspec[1] + 16; /* +16, for start of PPI */
+ break;
+ default:
+ pr_info("gic_irq_domain_translate_dt: invalid gic intr type\n");
+ return -EINVAL;
+ }
+
+ *out_hwirq += d->irq_base;
+ *out_type = IRQ_TYPE_NONE;
+ return 0;
+}
+
+static struct irq_domain_ops gic_irq_domain_dt_ops = {
+ .dt_translate = gic_irq_domain_translate_dt,
+};
+
+int gic_add_irq_domain_dt(unsigned int irq_base)
+{
+ struct device_node *np;
+ struct irq_domain *domain;
+
+ np = of_find_compatible_node(NULL, NULL, "arm,cortex-a9-gic");
+ if (!np)
+ return -ENODEV;
+
+ domain = kzalloc(sizeof(*domain), GFP_KERNEL);
+ if (!domain)
+ return -ENOMEM;
+
+ domain->irq_base = irq_base;
+ domain->of_node = np;
+ domain->ops = &gic_irq_domain_dt_ops;
+ irq_domain_add(domain);
+ return 0;
+}
+#endif
--
1.7.4.1
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