x86: dt: Use linear irq domain for ioapic(s)

The former conversion to irq_domain_add_legacy() did not fully work
since we miss the irq decs for NR_IRQS_LEGACY+.

Ideally we could use irq_domain_add_simple() or the no-map variant (and
program the virq <-> line mapping directly into ioapic) but this would
require a different irq lookup in "do_IRQ()" and won't work with ACPI
without changes. So this is probably easiest for everyone.

Tested-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Grant Likely <grant.likely@secretlab.ca>
Link: http://lkml.kernel.org/r/20120813202304.GA3529@breakpoint.cc
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 42 insertions, 9 deletions

diff --git a/arch/x86/kernel/devicetree.c b/arch/x86/kernel/devicetree.c
index 3ae2ced4a87..b1581527a23 100644
--- a/arch/x86/kernel/devicetree.c
+++ b/arch/x86/kernel/devicetree.c
@@ -342,6 +342,47 @@ const struct irq_domain_ops ioapic_irq_domain_ops = {
         .xlate = ioapic_xlate,
 };
 
+static void dt_add_ioapic_domain(unsigned int ioapic_num,
+                struct device_node *np)
+{
+        struct irq_domain *id;
+        struct mp_ioapic_gsi *gsi_cfg;
+        int ret;
+        int num;
+
+        gsi_cfg = mp_ioapic_gsi_routing(ioapic_num);
+        num = gsi_cfg->gsi_end - gsi_cfg->gsi_base + 1;
+
+        id = irq_domain_add_linear(np, num, &ioapic_irq_domain_ops,
+                        (void *)ioapic_num);
+        BUG_ON(!id);
+        if (gsi_cfg->gsi_base == 0) {
+                /*
+                 * The first NR_IRQS_LEGACY irq descs are allocated in
+                 * early_irq_init() and need just a mapping. The
+                 * remaining irqs need both. All of them are preallocated
+                 * and assigned so we can keep the 1:1 mapping which the ioapic
+                 * is having.
+                 */
+                ret = irq_domain_associate_many(id, 0, 0, NR_IRQS_LEGACY);
+                if (ret)
+                        pr_err("Error mapping legacy IRQs: %d\n", ret);
+
+                if (num > NR_IRQS_LEGACY) {
+                        ret = irq_create_strict_mappings(id, NR_IRQS_LEGACY,
+                                        NR_IRQS_LEGACY, num - NR_IRQS_LEGACY);
+                        if (ret)
+                                pr_err("Error creating mapping for the "
+                                                "remaining IRQs: %d\n", ret);
+                }
+                irq_set_default_host(id);
+        } else {
+                ret = irq_create_strict_mappings(id, gsi_cfg->gsi_base, 0, num);
+                if (ret)
+                        pr_err("Error creating IRQ mapping: %d\n", ret);
+        }
+}
+
 static void __init ioapic_add_ofnode(struct device_node *np)
 {
         struct resource r;
@@ -356,15 +397,7 @@ static void __init ioapic_add_ofnode(struct device_node *np)
 
         for (i = 0; i < nr_ioapics; i++) {
                 if (r.start == mpc_ioapic_addr(i)) {
-                        struct irq_domain *id;
-                        struct mp_ioapic_gsi *gsi_cfg;
-
-                        gsi_cfg = mp_ioapic_gsi_routing(i);
-
-                        id = irq_domain_add_legacy(np, 32, gsi_cfg->gsi_base, 0,
-                                                   &ioapic_irq_domain_ops,
-                                                   (void*)i);
-                        BUG_ON(!id);
+                        dt_add_ioapic_domain(i, np);
                         return;
                 }
         }