x86: coreboot: Allow building an SPL image

Make a few adjustments to allow us to build an SPL image for coreboot.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>

arch/x86/cpu/Makefile

@@ -54,9 +54,11 @@ obj-$(CONFIG_INTEL_QUARK) += quark/
 obj-$(CONFIG_INTEL_QUEENSBAY) += queensbay/
 obj-$(CONFIG_INTEL_TANGIER) += tangier/
 obj-$(CONFIG_APIC) += lapic.o ioapic.o
-obj-$(CONFIG_$(SPL_TPL_)X86_32BIT_INIT) += irq.o
 obj-$(CONFIG_$(SPL_TPL_)ACPI_GPE) += acpi_gpe.o
 obj-$(CONFIG_QFW) += qfw_cpu.o
+ifndef CONFIG_SYS_COREBOOT
+obj-$(CONFIG_$(SPL_TPL_)X86_32BIT_INIT) += irq.o
+endif
 ifndef CONFIG_$(SPL_)X86_64
 obj-$(CONFIG_SMP) += mp_init.o
 endif

arch/x86/cpu/coreboot/Makefile

@@ -11,8 +11,14 @@
 # (C) Copyright 2002
 # Daniel Engström, Omicron Ceti AB, daniel@omicron.se.
 
+ifndef CONFIG_SPL
 obj-y += car.o
+endif
+ifdef CONFIG_SPL_BUILD
+obj-y += coreboot_spl.o
+else
+obj-y += sdram.o
+endif
 obj-y += coreboot.o
 obj-y += tables.o
-obj-y += sdram.o
 obj-y += timestamp.o

arch/x86/cpu/coreboot/coreboot.c

@@ -27,7 +27,8 @@ int arch_cpu_init(void)
 
 	timestamp_init();
 
-	return x86_cpu_init_f();
+	return IS_ENABLED(CONFIG_X86_RUN_64BIT) ? x86_cpu_reinit_f() :
+		 x86_cpu_init_f();
 }
 
 int checkcpu(void)

arch/x86/cpu/coreboot/coreboot_spl.c

@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2020 Google LLC
+ */
+
+#include <common.h>
+#include <init.h>
+
+int dram_init(void)
+{
+	return 0;
+}

arch/x86/cpu/intel_common/Makefile

@@ -32,6 +32,8 @@ obj-$(CONFIG_HAVE_P2SB) += p2sb.o
 
 ifdef CONFIG_SPL
 ifndef CONFIG_SPL_BUILD
+ifndef CONFIG_SYS_COREBOOT
 obj-y += cpu_from_spl.o
 endif
 endif
+endif

arch/x86/cpu/x86_64/cpu.c

@@ -53,6 +53,7 @@ int misc_init_r(void)
 	return 0;
 }
 
+#ifndef CONFIG_SYS_COREBOOT
 int checkcpu(void)
 {
 	return 0;
@@ -62,6 +63,7 @@ int print_cpuinfo(void)
 {
 	return 0;
 }
+#endif
 
 int x86_cpu_reinit_f(void)
 {