soc/amd/cezanne: add SMU support

BUG=b:181766974

Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: I5b9b4c3d57945ea7c3287cf47f3d9704f42ff24b
Reviewed-on: https://review.coreboot.org/c/coreboot/+/51233
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Marshall Dawson <marshalldawson3rd@gmail.com>

src/soc/amd/cezanne/Kconfig

@@ -42,6 +42,7 @@ config SOC_SPECIFIC_OPTIONS
 	select SOC_AMD_COMMON_BLOCK_SMBUS
 	select SOC_AMD_COMMON_BLOCK_SMI
 	select SOC_AMD_COMMON_BLOCK_SMM
+	select SOC_AMD_COMMON_BLOCK_SMU
 	select SOC_AMD_COMMON_BLOCK_SPI
 	select SOC_AMD_COMMON_BLOCK_TSC_FAM17H_19H
 	select SOC_AMD_COMMON_BLOCK_UART

src/soc/amd/cezanne/Makefile.inc

@@ -37,6 +37,7 @@ ramstage-y	+= root_complex.c
 ramstage-y	+= uart.c
 
 smm-y		+= smihandler.c
+smm-y		+= smu.c
 smm-$(CONFIG_DEBUG_SMI) += uart.c
 
 CPPFLAGS_common += -I$(src)/soc/amd/cezanne/include

src/soc/amd/cezanne/include/soc/smu.h

@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef AMD_CEZANNE_SMU_H
+#define AMD_CEZANNE_SMU_H
+
+/*
+ * SMU mailbox register offsets in indirect address space accessed by an index/data pair in
+ * D0F00 config space.
+ */
+#define REG_ADDR_MESG_ID	0x3b10528
+#define REG_ADDR_MESG_RESP	0x3b10564
+#define REG_ADDR_MESG_ARGS_BASE	0x3b10998
+
+#define SMU_NUM_ARGS		6
+
+enum smu_message_id {
+	SMC_MSG_S3ENTRY = 0x0b,
+};
+
+/*
+ * Request the SMU put system into S3, S4, or S5. On entry, SlpTyp determines S-State and
+ * SlpTypeEn gets set by the SMU. Function does not return if successful.
+ */
+void smu_sx_entry(void);
+
+#endif /* AMD_CEZANNE_SMU_H */

src/soc/amd/cezanne/smu.c

@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <console/console.h>
+#include <amdblocks/smu.h>
+#include <soc/smu.h>
+
+/*
+ * Request the SMU to put system into S3, S4, or S5. On entry, SlpTyp determines S-State and
+ * SlpTypeEn gets set by the SMU. Function does not return if successful.
+ */
+void smu_sx_entry(void)
+{
+	struct smu_payload msg = { 0 }; /* Unused for SMC_MSG_S3ENTRY */
+
+	printk(BIOS_DEBUG, "SMU: Put system into S3/S4/S5\n");
+	send_smu_message(SMC_MSG_S3ENTRY, &msg);
+}