arch/x86: drivers/loapic_intr.c: move local APIC initialization

In the general case, the local APIC can't be treated as a normal device
with a single boot-time initialization - on SMP systems, each CPU must
initialize its own. Hence the initialization proper is separated from
the device-driver initialization, and said initialization is called
from the early startup-assembly code when appropriate.

Signed-off-by: Charles E. Youse <charles.youse@intel.com>

arch/x86/core/ia32/crt0.S

@@ -235,6 +235,10 @@ __csSet:
 #endif
 	lidt	z_x86_idt		/* load 32-bit operand size IDT */
 
+#ifdef CONFIG_LOAPIC
+	call	z_loapic_enable
+#endif
+
 	pushl	%ebx		/* pointer to multiboot info, or NULL */
 	call	z_x86_prep_c	/* enter kernel; never returns */
 

arch/x86/core/intel64/locore.S

@@ -88,6 +88,10 @@ __start:
 	xorl %edi, %edi
 	call x86_sse_init
 
+#ifdef CONFIG_LOAPIC
+	call z_loapic_enable
+#endif
+
 	/* don't replace CALL with JMP; honor the ABI stack alignment! */
 
 	movl %ebx, %edi		/* multiboot pointer (or NULL) */

drivers/interrupt_controller/loapic_intr.c

@@ -66,18 +66,13 @@ static u32_t loapic_device_power_state = DEVICE_PM_ACTIVE_STATE;
 #endif
 
 /**
+ * @brief Enable and initialize the local APIC.
  *
- * @brief Initialize the Local APIC or xAPIC
+ * Called from early assembly layer (e.g., crt0.S).
- *
- * This routine initializes Local APIC or xAPIC.
- *
- * @return N/A
- *
  */
 
-static int loapic_init(struct device *unused)
+void z_loapic_enable(void)
 {
-	ARG_UNUSED(unused);
 	s32_t loApicMaxLvt; /* local APIC Max LVT */
 
 	/*
@@ -150,7 +145,19 @@ static int loapic_init(struct device *unused)
 
 	/* discard a pending interrupt if any */
 	x86_write_loapic(LOAPIC_EOI, 0);
+}
 
+/**
+ *
+ * @brief Dummy initialization function.
+ *
+ * The local APIC is initialized via z_loapic_enable() long before the
+ * kernel runs through its device initializations, so this is unneeded.
+ */
+
+static int loapic_init(struct device *unused)
+{
+	ARG_UNUSED(unused);
 	return 0;
 }
 

include/drivers/interrupt_controller/loapic.h

@@ -49,6 +49,7 @@
 extern "C" {
 #endif
 
+extern void z_loapic_enable(void);
 extern void z_loapic_int_vec_set(unsigned int irq, unsigned int vector);
 extern void z_loapic_irq_enable(unsigned int irq);
 extern void z_loapic_irq_disable(unsigned int irq);