Change in coreboot[master]: libpayload/apic: Register a spurious interrupt vector

[Martin Roth (Code Review)]

Martin Roth has submitted this change and it was merged. ( https://review.coreboot.org/28880 )

Change subject: libpayload/apic: Register a spurious interrupt vector
......................................................................

libpayload/apic: Register a spurious interrupt vector

We should have a spurious interrupt vector just incase we get one. The
handler doesn't need to do anything.

BUG=b:116777191
TEST=Booted depthcharge on grunt and inspected the register. I can't
generate a spurious interrupt, so I can't validate that the handler gets
called.

Change-Id: I9e49e617f4375eb5eb00d0715c1902f77e2bf284
Signed-off-by: Raul E Rangel 
Reviewed-on: https://review.coreboot.org/28880
Tested-by: build bot (Jenkins) 
Reviewed-by: Martin Roth 
---
M payloads/libpayload/arch/x86/apic.c
1 file changed, 21 insertions(+), 2 deletions(-)

Approvals:
  build bot (Jenkins): Verified
  Martin Roth: Looks good to me, approved

diff --git a/payloads/libpayload/arch/x86/apic.c b/payloads/libpayload/arch/x86/apic.c
index 3b294cb..db81ea1 100644
--- a/payloads/libpayload/arch/x86/apic.c
+++ b/payloads/libpayload/arch/x86/apic.c
@@ -42,7 +42,6 @@
 #define XAPIC_ENABLED_BIT		(1 << 11)
 #define X2APIC_ENABLED_BIT		(1 << 10)
 #define APIC_MASKED_BIT			(1 << 16)
-#define APIC_SW_ENABLED_BIT		(1 << 8)

#define APIC_ID				0x020
 #define   APIC_ID_SHIFT			24
@@ -54,6 +53,9 @@
 #define   APIC_TASK_PRIORITY_MASK	0xFFUL
 #define APIC_EOI			0x0B0
 #define APIC_SPURIOUS			0x0F0
+#define   APIC_SW_ENABLED_BIT		(1 << 8)
+#define   APIC_SPURIOUS_VECTOR_MASK	0xFFUL
+#define APIC_SPURIOUS			0x0F0
 #define APIC_LVT_TIMER			0x320
 #define APIC_TIMER_INIT_COUNT		0x380
 #define APIC_TIMER_CUR_COUNT		0x390
@@ -63,7 +65,8 @@

#define APIC_LVT_SIZE			0x010

-#define APIC_TIMER_VECTOR		0x20
+#define APIC_TIMER_VECTOR		0x20UL
+#define APIC_SPURIOUS_VECTOR		0xFFUL

static uint32_t apic_bar;
 static int _apic_initialized;
@@ -143,6 +146,8 @@
    timer_waiting = 0;
 }

+static void suprious_interrupt_handler(u8 vector) {}
+
 void apic_eoi(uint8_t vector)
 {
    die_if(!apic_bar, "APIC is not initialized");
@@ -255,6 +260,17 @@
    apic_write32(APIC_SPURIOUS, reg);
 }

+static void apic_setup_spurious(void)
+{
+	uint32_t reg = apic_read32(APIC_SPURIOUS);
+
+	reg &= ~APIC_SPURIOUS_VECTOR_MASK;
+
+	reg |= APIC_SPURIOUS_VECTOR;
+
+	apic_write32(APIC_SPURIOUS, reg);
+}
+
 void apic_init(void)
 {
    uint64_t apic_bar_reg;
@@ -274,12 +290,15 @@

apic_reset_all_lvts();
    apic_set_task_priority(0);
+	apic_setup_spurious();

apic_sw_enable();

apic_init_timer();

set_interrupt_handler(APIC_TIMER_VECTOR, &timer_interrupt_handler);
+	set_interrupt_handler(APIC_SPURIOUS_VECTOR,
+			      &suprious_interrupt_handler);

_apic_initialized = 1;