soc/amd: introduce and use get_uvolts_from_vid for SVI2 and SVI3

Instead of implementing the conversion from the raw serial voltage ID
value to the voltage in microvolts in every SoC, introduce the
SOC_AMD_COMMON_BLOCK_SVI[2,3] Kconfig options for the SoC to select the
correct version, implement get_uvolts_from_vid for both cases and only
include the selected implementation in the build.

Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: I344641217e6e4654fd281d434b88e346e0482f57
Reviewed-on: https://review.coreboot.org/c/coreboot/+/73995
Reviewed-by: Fred Reitberger <reitbergerfred@gmail.com>
Reviewed-by: Matt DeVillier <matt.devillier@amd.corp-partner.google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

5 files changed, 54 insertions, 0 deletions

diff --git a/src/soc/amd/common/block/cpu/Kconfig b/src/soc/amd/common/block/cpu/Kconfig
index f7583e720a..5dc846bb00 100644
--- a/src/soc/amd/common/block/cpu/Kconfig
+++ b/src/soc/amd/common/block/cpu/Kconfig
@@ -66,6 +66,18 @@ config SOC_AMD_COMMON_BLOCK_SMM
 	  Add common SMM relocation, finalization and handler functionality to
 	  the build.
 
+config SOC_AMD_COMMON_BLOCK_SVI2
+	bool
+	help
+	  Select this option is the SoC uses the serial VID 2 standard for
+	  encoding the voltage it requests from the VRM.
+
+config SOC_AMD_COMMON_BLOCK_SVI3
+	bool
+	help
+	  Select this option is the SoC uses the serial VID 3 standard for
+	  encoding the voltage it requests from the VRM.
+
 config SOC_AMD_COMMON_BLOCK_TSC_FAM17H_19H
 	bool
 	select COLLECT_TIMESTAMPS_NO_TSC # selected use SoC-specific timestamp function
diff --git a/src/soc/amd/common/block/cpu/Makefile.inc b/src/soc/amd/common/block/cpu/Makefile.inc
index bd9e8ff88f..055341ec4d 100644
--- a/src/soc/amd/common/block/cpu/Makefile.inc
+++ b/src/soc/amd/common/block/cpu/Makefile.inc
@@ -4,6 +4,9 @@ ramstage-$(CONFIG_SOC_AMD_COMMON_BLOCK_UCODE) += update_microcode.c
 romstage-y += cpu.c
 ramstage-y += cpu.c
 
+ramstage-$(CONFIG_SOC_AMD_COMMON_BLOCK_SVI2) += svi2.c
+ramstage-$(CONFIG_SOC_AMD_COMMON_BLOCK_SVI3) += svi3.c
+
 ifeq ($(CONFIG_SOC_AMD_COMMON_BLOCK_UCODE),y)
 define add-ucode-as-cbfs
 cbfs-files-y += cpu_microcode_$(2).bin
diff --git a/src/soc/amd/common/block/cpu/svi2.c b/src/soc/amd/common/block/cpu/svi2.c
new file mode 100644
index 0000000000..0a41b78b26
--- /dev/null
+++ b/src/soc/amd/common/block/cpu/svi2.c
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <amdblocks/cpu.h>
+#include <types.h>
+
+/* Value defined in Serial VID Interface 2.0 spec (#48022, NDA only) */
+#define  SERIAL_VID_2_DECODE_MICROVOLTS	6250
+#define  SERIAL_VID_2_MAX_MICROVOLTS	1550000L
+
+uint32_t get_uvolts_from_vid(uint16_t core_vid)
+{
+	if ((core_vid >= 0xF8) && (core_vid <= 0xFF)) {
+		/* Voltage off for VID codes 0xF8 to 0xFF */
+		return 0;
+	} else {
+		return SERIAL_VID_2_MAX_MICROVOLTS -
+			(SERIAL_VID_2_DECODE_MICROVOLTS * core_vid);
+	}
+}
diff --git a/src/soc/amd/common/block/cpu/svi3.c b/src/soc/amd/common/block/cpu/svi3.c
new file mode 100644
index 0000000000..35a4a789de
--- /dev/null
+++ b/src/soc/amd/common/block/cpu/svi3.c
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <amdblocks/cpu.h>
+#include <types.h>
+
+/* Value defined in Serial VID Interface 3.0 spec (#56413, NDA only) */
+#define  SERIAL_VID_3_DECODE_MICROVOLTS	5000
+#define  SERIAL_VID_3_BASE_MICROVOLTS	245000L
+
+uint32_t get_uvolts_from_vid(uint16_t core_vid)
+{
+	if (core_vid == 0x00) {
+		/* Voltage off for VID code 0x00 */
+		return 0;
+	} else {
+		return SERIAL_VID_3_BASE_MICROVOLTS +
+			(SERIAL_VID_3_DECODE_MICROVOLTS * core_vid);
+	}
+}
diff --git a/src/soc/amd/common/block/include/amdblocks/cpu.h b/src/soc/amd/common/block/include/amdblocks/cpu.h
index 3501b22104..cbce028631 100644
--- a/src/soc/amd/common/block/include/amdblocks/cpu.h
+++ b/src/soc/amd/common/block/include/amdblocks/cpu.h
@@ -16,6 +16,7 @@ void write_resume_eip(void);
 
 union pstate_msr; /* proper definition is in soc/msr.h */
 
+uint32_t get_uvolts_from_vid(uint16_t core_vid);
 uint32_t get_pstate_core_freq(union pstate_msr pstate_reg);
 uint32_t get_pstate_core_power(union pstate_msr pstate_reg);
 const acpi_cstate_t *get_cstate_config_data(size_t *size);