cpu/x86/lapic: Add lapic_busy() helper

Change-Id: Ife127d6dc8241cccb9d52236a9152da707f0e261
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/55191
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Wonkyu Kim <wonkyu.kim@intel.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/include/cpu/x86/lapic.h b/src/include/cpu/x86/lapic.h
index 1db0ff4..4647877 100644
--- a/src/include/cpu/x86/lapic.h
+++ b/src/include/cpu/x86/lapic.h
@@ -35,6 +35,11 @@
 	xapic_write_atomic(LAPIC_ICR, icrlow);
 }
 
+static __always_inline int xapic_busy(void)
+{
+	return xapic_read(LAPIC_ICR) & LAPIC_ICR_BUSY;
+}
+
 #define lapic_read_around(x) lapic_read(x)
 #define lapic_write_around(x, y) xapic_write_atomic((x), (y))
 
@@ -124,9 +129,12 @@
 		xapic_send_ipi(icrlow, apicid);
 }
 
-static __always_inline void lapic_wait_icr_idle(void)
+static __always_inline int lapic_busy(void)
 {
-	do { } while (lapic_read(LAPIC_ICR) & LAPIC_ICR_BUSY);
+	if (is_x2apic_mode())
+		return 0;
+	else
+		return xapic_busy();
 }
 
 static __always_inline unsigned int initial_lapicid(void)