ARM: at91/aic: add irq domain and device tree support

Add an irqdomain for the AIC interrupt controller.
The device tree support is mapping the registers and
is using the irq_domain_add_legacy() to manage hwirq
translation.
The documentation is describing the meaning of the
two cells required for using this "interrupt-controller"
in a device tree node.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

1 files changed, 61 insertions, 13 deletions

diff --git a/arch/arm/mach-at91/irq.c b/arch/arm/mach-at91/irq.c
index be6b639ecd7b..46682fafa96f 100644
--- a/arch/arm/mach-at91/irq.c
+++ b/arch/arm/mach-at91/irq.c
@@ -24,6 +24,12 @@
 #include <linux/module.h>
 #include <linux/mm.h>
 #include <linux/types.h>
+#include <linux/irq.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/err.h>
 
 #include <mach/hardware.h>
 #include <asm/irq.h>
@@ -34,22 +40,24 @@
 #include <asm/mach/map.h>
 
 void __iomem *at91_aic_base;
+static struct irq_domain *at91_aic_domain;
+static struct device_node *at91_aic_np;
 
 static void at91_aic_mask_irq(struct irq_data *d)
 {
         /* Disable interrupt on AIC */
-        at91_aic_write(AT91_AIC_IDCR, 1 << d->irq);
+        at91_aic_write(AT91_AIC_IDCR, 1 << d->hwirq);
 }
 
 static void at91_aic_unmask_irq(struct irq_data *d)
 {
         /* Enable interrupt on AIC */
-        at91_aic_write(AT91_AIC_IECR, 1 << d->irq);
+        at91_aic_write(AT91_AIC_IECR, 1 << d->hwirq);
 }
 
 unsigned int at91_extern_irq;
 
-#define is_extern_irq(irq) ((1 << (irq)) & at91_extern_irq)
+#define is_extern_irq(hwirq) ((1 << (hwirq)) & at91_extern_irq)
 
 static int at91_aic_set_type(struct irq_data *d, unsigned type)
 {
@@ -63,13 +71,13 @@ static int at91_aic_set_type(struct irq_data *d, unsigned type)
                 srctype = AT91_AIC_SRCTYPE_RISING;
                 break;
         case IRQ_TYPE_LEVEL_LOW:
-                if ((d->irq == AT91_ID_FIQ) || is_extern_irq(d->irq))           /* only supported on external interrupts */
+                if ((d->hwirq == AT91_ID_FIQ) || is_extern_irq(d->hwirq))               /* only supported on external interrupts */
                         srctype = AT91_AIC_SRCTYPE_LOW;
                 else
                         return -EINVAL;
                 break;
         case IRQ_TYPE_EDGE_FALLING:
-                if ((d->irq == AT91_ID_FIQ) || is_extern_irq(d->irq))           /* only supported on external interrupts */
+                if ((d->hwirq == AT91_ID_FIQ) || is_extern_irq(d->hwirq))               /* only supported on external interrupts */
                         srctype = AT91_AIC_SRCTYPE_FALLING;
                 else
                         return -EINVAL;
@@ -78,8 +86,8 @@ static int at91_aic_set_type(struct irq_data *d, unsigned type)
                 return -EINVAL;
         }
 
-        smr = at91_aic_read(AT91_AIC_SMR(d->irq)) & ~AT91_AIC_SRCTYPE;
-        at91_aic_write(AT91_AIC_SMR(d->irq), smr | srctype);
+        smr = at91_aic_read(AT91_AIC_SMR(d->hwirq)) & ~AT91_AIC_SRCTYPE;
+        at91_aic_write(AT91_AIC_SMR(d->hwirq), smr | srctype);
         return 0;
 }
 
@@ -90,13 +98,13 @@ static u32 backups;
 
 static int at91_aic_set_wake(struct irq_data *d, unsigned value)
 {
-        if (unlikely(d->irq >= 32))
+        if (unlikely(d->hwirq >= NR_AIC_IRQS))
                 return -EINVAL;
 
         if (value)
-                wakeups |= (1 << d->irq);
+                wakeups |= (1 << d->hwirq);
         else
-                wakeups &= ~(1 << d->irq);
+                wakeups &= ~(1 << d->hwirq);
 
         return 0;
 }
@@ -127,24 +135,64 @@ static struct irq_chip at91_aic_chip = {
         .irq_set_wake   = at91_aic_set_wake,
 };
 
+#if defined(CONFIG_OF)
+static int __init __at91_aic_of_init(struct device_node *node,
+                                     struct device_node *parent)
+{
+        at91_aic_base = of_iomap(node, 0);
+        at91_aic_np = node;
+
+        return 0;
+}
+
+static const struct of_device_id aic_ids[] __initconst = {
+        { .compatible = "atmel,at91rm9200-aic", .data = __at91_aic_of_init },
+        { /*sentinel*/ }
+};
+
+static void __init at91_aic_of_init(void)
+{
+        of_irq_init(aic_ids);
+}
+#else
+static void __init at91_aic_of_init(void) {}
+#endif
+
 /*
  * Initialize the AIC interrupt controller.
  */
 void __init at91_aic_init(unsigned int priority[NR_AIC_IRQS])
 {
         unsigned int i;
+        int irq_base;
 
-        at91_aic_base = ioremap(AT91_AIC, 512);
+        if (of_have_populated_dt())
+                at91_aic_of_init();
+        else
+                at91_aic_base = ioremap(AT91_AIC, 512);
 
         if (!at91_aic_base)
-                panic("Impossible to ioremap AT91_AIC\n");
+                panic("Unable to ioremap AIC registers\n");
+
+        /* Add irq domain for AIC */
+        irq_base = irq_alloc_descs(-1, 0, NR_AIC_IRQS, 0);
+        if (irq_base < 0) {
+                WARN(1, "Cannot allocate irq_descs, assuming pre-allocated\n");
+                irq_base = 0;
+        }
+        at91_aic_domain = irq_domain_add_legacy(at91_aic_np, NR_AIC_IRQS,
+                                                irq_base, 0,
+                                                &irq_domain_simple_ops, NULL);
+
+        if (!at91_aic_domain)
+                panic("Unable to add AIC irq domain\n");
 
         /*
          * The IVR is used by macro get_irqnr_and_base to read and verify.
          * The irq number is NR_AIC_IRQS when a spurious interrupt has occurred.
          */
         for (i = 0; i < NR_AIC_IRQS; i++) {
-                /* Put irq number in Source Vector Register: */
+                /* Put hardware irq number in Source Vector Register: */
                 at91_aic_write(AT91_AIC_SVR(i), i);
                 /* Active Low interrupt, with the specified priority */
                 at91_aic_write(AT91_AIC_SMR(i), AT91_AIC_SRCTYPE_LOW | priority[i]);