mb/google/volteer/var/elemi: enable Genesys Logic GL9763E

Enable Genesys GL9763E as PCI-to-eMMC bridge.

BUG=b:171467336
BRANCH=volteer
TEST=emerge-volteer coreboot

Signed-off-by: Wisley Chen <wisley.chen@quantatw.com>
Change-Id: I858c12151df5b6fc19132869317edfa1b090335d
Reviewed-on: https://review.coreboot.org/c/coreboot/+/47040
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>

src/mainboard/google/volteer/Kconfig

@@ -3,6 +3,7 @@ config BOARD_GOOGLE_BASEBOARD_VOLTEER
 	select BOARD_ROMSIZE_KB_32768
 	select DRIVERS_GENERIC_GPIO_KEYS
 	select DRIVERS_GENERIC_MAX98357A
+	select DRIVERS_GENESYSLOGIC_GL9763E
 	select DRIVERS_I2C_GENERIC
 	select DRIVERS_I2C_HID
 	select DRIVERS_I2C_SX9310

src/mainboard/google/volteer/variants/elemi/overridetree.cb

@@ -6,6 +6,13 @@ chip soc/intel/tigerlake
 	register "IomTypeCPortPadCfg[0]" = "0x090E000A"
 	register "IomTypeCPortPadCfg[1]" = "0x090E000D"
 
+        # Enable EMMC PCIE 5 using clk 5
+        register "PcieRpEnable[4]" = "1"
+        register "PcieRpLtrEnable[4]" = "1"
+        register "PcieRpHotPlug[4]" = "1"
+        register "PcieClkSrcUsage[5]" = "4"
+        register "PcieClkSrcClkReq[5]" = "5"
+
 	#+-------------------+---------------------------+
 	#| Field             |  Value                    |
 	#+-------------------+---------------------------+
@@ -184,6 +191,7 @@ chip soc/intel/tigerlake
 				device generic 0 on end
 			end
 		end
+		device ref pcie_rp5 on end
 		device ref pmc hidden
 			# The pmc_mux chip driver is a placeholder for the
 			# PMC.MUX device in the ACPI hierarchy.