soc/intel/elkhartlake: Make SATA speed limit configurable

In cases where there are limitations on the mainboard it can be
necessary to limit the used SATA speed even though both, the SATA
controller and disk drive support a higher speed rate. The FSP parameter
'SataSpeedLimit' allows to set the speed limit.

This patch provides a chip config so that this FSP parameter can be
set as needed in the devicetree on mainboard level.

Change-Id: I610263b34b0947378d2025211ece4a9ec8fbfef6
Signed-off-by: Werner Zeh <werner.zeh@siemens.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/71229
Reviewed-by: Paul Menzel <paulepanter@mailbox.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Mario Scheithauer <mario.scheithauer@siemens.com>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>

src/soc/intel/elkhartlake/chip.h

@@ -103,6 +103,13 @@ enum fivr_supported_voltage {
 					  FIVR_VOLTAGE_MIN_RETENTION,
 };
 
+/* SATA speed limit */
+enum sata_speed_limit {
+	SATA_DEFAULT = 0,
+	SATA_GEN1,
+	SATA_GEN2
+};
+
 struct soc_intel_elkhartlake_config {
 
 	/* Common struct containing soc config data required by common code */
@@ -181,6 +188,7 @@ struct soc_intel_elkhartlake_config {
 	uint8_t SataSalpSupport;
 	uint8_t SataPortsEnable[CONFIG_MAX_SATA_PORTS];
 	uint8_t SataPortsDevSlp[CONFIG_MAX_SATA_PORTS];
+	enum sata_speed_limit SataSpeed;
 	/*
 	 * Enable(0)/Disable(1) SATA Power Optimizer on PCH side.
 	 * Default 0. Setting this to 1 disables the SATA Power Optimizer.

src/soc/intel/elkhartlake/fsp_params.c

@@ -368,6 +368,7 @@ void platform_fsp_silicon_init_params_cb(FSPS_UPD *supd)
 		params->SataMode = config->SataMode;
 		params->SataSalpSupport = config->SataSalpSupport;
 		params->SataPwrOptEnable = !(config->SataPwrOptimizeDisable);
+		params->SataSpeedLimit = config->SataSpeed;
 
 		for (i = 0; i < CONFIG_MAX_SATA_PORTS; i++) {
 			params->SataPortsEnable[i] = config->SataPortsEnable[i];