x86: ioapic: Add OF bindings for IO_APIC

ioapic_xlate provides a translation from the information in device tree
to ioapic related informations. This includes
- obtaining hw irq which is the vector number "=> pin number + gsi"
- obtaining type (level/edge/..)
- programming this information into ioapic

ioapic_add_ofnode adds an irq_domain based on informations from the device
tree. This information (irq_domain) is required in order to map a device to
its proper interrupt controller.

[ tglx: Adapted to the io_apic changes, which let us move that whole code
  	to devicetree.c ]

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Dirk Brandewie <dirk.brandewie@gmail.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Cc: sodaville@linutronix.de
Cc: devicetree-discuss@lists.ozlabs.org
LKML-Reference: <1298405266-1624-10-git-send-email-bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

2 files changed, 110 insertions, 0 deletions

diff --git a/arch/x86/kernel/devicetree.c b/arch/x86/kernel/devicetree.c
index 0bc83bfa4ead..2d65897a39d0 100644
--- a/arch/x86/kernel/devicetree.c
+++ b/arch/x86/kernel/devicetree.c
@@ -320,3 +320,107 @@ void __init x86_dtb_get_config(unsigned int unused)
         dtb_setup_hpet();
         dtb_apic_setup();
 }
+
+#ifdef CONFIG_X86_IO_APIC
+
+struct of_ioapic_type {
+        u32 out_type;
+        u32 trigger;
+        u32 polarity;
+};
+
+static struct of_ioapic_type of_ioapic_type[] =
+{
+        {
+                .out_type       = IRQ_TYPE_EDGE_RISING,
+                .trigger        = IOAPIC_EDGE,
+                .polarity       = 1,
+        },
+        {
+                .out_type       = IRQ_TYPE_LEVEL_LOW,
+                .trigger        = IOAPIC_LEVEL,
+                .polarity       = 0,
+        },
+        {
+                .out_type       = IRQ_TYPE_LEVEL_HIGH,
+                .trigger        = IOAPIC_LEVEL,
+                .polarity       = 1,
+        },
+        {
+                .out_type       = IRQ_TYPE_EDGE_FALLING,
+                .trigger        = IOAPIC_EDGE,
+                .polarity       = 0,
+        },
+};
+
+static int ioapic_xlate(struct irq_domain *id, const u32 *intspec, u32 intsize,
+                        u32 *out_hwirq, u32 *out_type)
+{
+        struct io_apic_irq_attr attr;
+        struct of_ioapic_type *it;
+        u32 line, idx, type;
+
+        if (intsize < 2)
+                return -EINVAL;
+
+        line = *intspec;
+        idx = (u32) id->priv;
+        *out_hwirq = line + mp_gsi_routing[idx].gsi_base;
+
+        intspec++;
+        type = *intspec;
+
+        if (type >= ARRAY_SIZE(of_ioapic_type))
+                return -EINVAL;
+
+        it = of_ioapic_type + type;
+        *out_type = it->out_type;
+
+        set_io_apic_irq_attr(&attr, idx, line, it->trigger, it->polarity);
+
+        return io_apic_setup_irq_pin(*out_hwirq, cpu_to_node(0), &attr);
+}
+
+static void __init ioapic_add_ofnode(struct device_node *np)
+{
+        struct resource r;
+        int i, ret;
+
+        ret = of_address_to_resource(np, 0, &r);
+        if (ret) {
+                printk(KERN_ERR "Failed to obtain address for %s\n",
+                                np->full_name);
+                return;
+        }
+
+        for (i = 0; i < nr_ioapics; i++) {
+                if (r.start == mp_ioapics[i].apicaddr) {
+                        struct irq_domain *id;
+
+                        id = kzalloc(sizeof(*id), GFP_KERNEL);
+                        BUG_ON(!id);
+                        id->controller = np;
+                        id->xlate = ioapic_xlate;
+                        id->priv = (void *)i;
+                        add_interrupt_host(id);
+                        return;
+                }
+        }
+        printk(KERN_ERR "IOxAPIC at %s is not registered.\n", np->full_name);
+}
+
+void __init x86_add_irq_domains(void)
+{
+        struct device_node *dp;
+
+        if (!initial_boot_params)
+                return;
+
+        for_each_node_with_property(dp, "interrupt-controller") {
+                if (of_device_is_compatible(dp, "intel,ce4100-ioapic"))
+                        ioapic_add_ofnode(dp);
+        }
+}
+#else
+void __init x86_add_irq_domains(void) { }
+#endif
diff --git a/arch/x86/kernel/irqinit.c b/arch/x86/kernel/irqinit.c
index 4cadf8688dbd..9f76f89f43a4 100644
--- a/arch/x86/kernel/irqinit.c
+++ b/arch/x86/kernel/irqinit.c
@@ -119,6 +119,12 @@ void __init init_IRQ(void)
         int i;
 
         /*
+         * We probably need a better place for this, but it works for
+         * now ...
+         */
+        x86_add_irq_domains();
+
+        /*
          * On cpu 0, Assign IRQ0_VECTOR..IRQ15_VECTOR's to IRQ 0..15.
          * If these IRQ's are handled by legacy interrupt-controllers like PIC,
          * then this configuration will likely be static after the boot. If