arch/x86: introduce HAVE_CONFIGURABLE_APMC_SMI_PORT

Introduce the HAVE_CONFIGURABLE_APMC_SMI_PORT Kconfig option that when
not selected will result in a default implementation of
pm_acpi_smi_cmd_port to be included in the build that returns APM_CNT.
SoCs that provide their own pm_acpi_smi_cmd_port implementation, need to
select this Kconfig option.

Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: Iaceb61b0f2a630d7afe2e0780b6a2a9806ea62f9
Reviewed-on: https://review.coreboot.org/c/coreboot/+/79566
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Rudolph <patrick.rudolph@9elements.com>
diff --git a/src/arch/x86/Kconfig b/src/arch/x86/Kconfig
index e149f08..0c11653 100644
--- a/src/arch/x86/Kconfig
+++ b/src/arch/x86/Kconfig
@@ -316,6 +316,13 @@
 	bool
 	depends on HAVE_CF9_RESET
 
+config HAVE_CONFIGURABLE_APMC_SMI_PORT
+	bool
+	help
+	  SoCs that have a configurable APMC SMI command port, should select
+	  this option and implement pm_acpi_smi_cmd_port() that returns the IO
+	  port.
+
 config PIRQ_ROUTE
 	bool
 	default n
diff --git a/src/arch/x86/Makefile.inc b/src/arch/x86/Makefile.inc
index 62294a6..04a0e58 100644
--- a/src/arch/x86/Makefile.inc
+++ b/src/arch/x86/Makefile.inc
@@ -336,3 +336,8 @@
 smm-$(CONFIG_DEBUG_NULL_DEREF_BREAKPOINTS_IN_ALL_STAGES) += null_breakpoint.c
 
 smm-srcs += $(wildcard src/mainboard/$(MAINBOARDDIR)/smihandler.c)
+
+ifneq ($(CONFIG_HAVE_CONFIGURABLE_APMC_SMI_PORT),y)
+ramstage-y += apmc_smi_port.c
+smm-y += apmc_smi_port.c
+endif
diff --git a/src/arch/x86/apmc_smi_port.c b/src/arch/x86/apmc_smi_port.c
new file mode 100644
index 0000000..ac8f336
--- /dev/null
+++ b/src/arch/x86/apmc_smi_port.c
@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <cpu/x86/smm.h>
+
+/* default implementation of the !HAVE_CONFIGURABLE_APMC_SMI_PORT case */
+uint16_t pm_acpi_smi_cmd_port(void)
+{
+	return APM_CNT;
+}
diff --git a/src/mainboard/emulation/qemu-q35/Makefile.inc b/src/mainboard/emulation/qemu-q35/Makefile.inc
index f4a89be..bc73edc 100644
--- a/src/mainboard/emulation/qemu-q35/Makefile.inc
+++ b/src/mainboard/emulation/qemu-q35/Makefile.inc
@@ -20,5 +20,4 @@
 
 ramstage-$(CONFIG_CHROMEOS) += chromeos.c
 
-smm-y += smi.c
 smm-y += memmap.c
diff --git a/src/mainboard/emulation/qemu-q35/smi.c b/src/mainboard/emulation/qemu-q35/smi.c
deleted file mode 100644
index 5d8d482..0000000
--- a/src/mainboard/emulation/qemu-q35/smi.c
+++ /dev/null
@@ -1,9 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-only */
-
-#include <cpu/x86/smm.h>
-
-/* The X86 qemu target uses AMD64 save states but the APM port is not configurable. */
-uint16_t pm_acpi_smi_cmd_port(void)
-{
-	return APM_CNT;
-}
diff --git a/src/soc/amd/common/block/smi/Kconfig b/src/soc/amd/common/block/smi/Kconfig
index b205437..5a3f42d 100644
--- a/src/soc/amd/common/block/smi/Kconfig
+++ b/src/soc/amd/common/block/smi/Kconfig
@@ -1,5 +1,6 @@
 config SOC_AMD_COMMON_BLOCK_SMI
 	bool
+	select HAVE_CONFIGURABLE_APMC_SMI_PORT
 	help
 	  Select this option to add the common functions for setting up the SMI
 	  configuration to the build.