mb/google/rex: Add EC smihandler

Add SMI handler implementation to manage power cycle,
power state transition and Chrome EC events.

BUG=b:224325352
TEST=util/abuild/abuild -p none -t google/rex -a -c max

Signed-off-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>
Change-Id: I10aab8257fce92aaf913a53c0c9fb6c1a4f5dea6
Reviewed-on: https://review.coreboot.org/c/coreboot/+/64623
Reviewed-by: Tarun Tuli <taruntuli@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/google/rex/Makefile.inc

@@ -9,6 +9,8 @@ ramstage-y += mainboard.c
 ramstage-$(CONFIG_CHROMEOS) += chromeos.c
 ramstage-y += ec.c
 
+smm-$(CONFIG_HAVE_SMI_HANDLER) += smihandler.c
+
 VARIANT_DIR:=$(call strip_quotes,$(CONFIG_VARIANT_DIR))
 BASEBOARD_DIR:=$(call strip_quotes,$(CONFIG_BASEBOARD_DIR))
 

src/mainboard/google/rex/smihandler.c

@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include <cpu/x86/smm.h>
+#include <ec/google/chromeec/ec.h>
+#include <ec/google/chromeec/smm.h>
+#include <elog.h>
+#include <intelblocks/smihandler.h>
+#include <variant/ec.h>
+
+void mainboard_smi_sleep(u8 slp_typ)
+{
+	chromeec_smi_sleep(slp_typ, MAINBOARD_EC_S3_WAKE_EVENTS, MAINBOARD_EC_S5_WAKE_EVENTS);
+}
+
+int mainboard_smi_apmc(u8 apmc)
+{
+	chromeec_smi_apmc(apmc, MAINBOARD_EC_SCI_EVENTS, MAINBOARD_EC_SMI_EVENTS);
+	return 0;
+}
+
+void elog_gsmi_cb_mainboard_log_wake_source(void)
+{
+	google_chromeec_log_events(MAINBOARD_EC_LOG_EVENTS | MAINBOARD_EC_S0IX_WAKE_EVENTS);
+}
+
+void mainboard_smi_espi_handler(void)
+{
+	chromeec_smi_process_events();
+}