[PATCH] x86/apic: Early setup IOAPIC for APB timer

[Jacob Pan]

Intel Moorestown platform uses APB system timers which rely
on IOAPIC to deliver its interrupts. Early setup the APIC
system is necessary to allow timer interrupts.

Signed-off-by: Jacob Pan <jacob.jun.pan@xxxxxxxxx>
---
 arch/x86/include/asm/apic.h    |    1 +
 arch/x86/kernel/apic/io_apic.c |   17 +++++++++++++++++
 2 files changed, 18 insertions(+), 0 deletions(-)

diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index 8b542f4..4f2d26d 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -84,6 +84,7 @@ extern void xapic_wait_icr_idle(void);
 extern u32 safe_xapic_wait_icr_idle(void);
 extern void xapic_icr_write(u32, u32);
 extern int setup_profiling_timer(unsigned int);
+extern void pre_init_apic_IRQ(void);
 
 static inline void native_apic_mem_write(u32 reg, u32 v)
 {
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index ccc746f..25a5b72 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -36,6 +36,7 @@
 #include <linux/freezer.h>
 #include <linux/kthread.h>
 #include <linux/jiffies.h>	/* time_after() */
+#include <linux/sfi.h>
 #ifdef CONFIG_ACPI
 #include <acpi/acpi_bus.h>
 #endif
@@ -63,6 +64,7 @@
 #include <asm/uv/uv_hub.h>
 #include <asm/uv/uv_irq.h>
 #include <asm/platform_feature.h>
+#include <asm/apb_timer.h>
 #include <asm/apic.h>
 
 #define __apicdebuginit(type) static type __init
@@ -4211,3 +4213,18 @@ void __init ioapic_insert_resources(void)
 		r++;
 	}
 }
+
+/* Enable IOAPIC early just for system timer */
+void __init pre_init_apic_IRQ(void)
+{
+	struct irq_cfg *cfg;
+
+	printk(KERN_INFO "Early APIC setup for system timer\n");
+#ifndef CONFIG_SMP
+	phys_cpu_present_map = physid_mask_of_physid(boot_cpu_physical_apicid);
+#endif
+	setup_local_APIC();
+	cfg = irq_cfg(0);
+	add_pin_to_irq_node(cfg, 0, 0, 0);
+	setup_timer_IRQ0_pin(0, 0, cfg->vector);
+}
-- 
1.5.6.5

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