mb/siemens/mc_ehl: Disable C-States for CPU and package

Disable all C-states other than C0/C1 for CPU and package.

Change-Id: I2c163f859dab4b0dc02896c70122e993cdd3db72
Signed-off-by: Werner Zeh <werner.zeh@siemens.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/58893
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Lean Sheng Tan <lean.sheng.tan@intel.com>
Reviewed-by: Mario Scheithauer <mario.scheithauer@siemens.com>
diff --git a/src/mainboard/siemens/mc_ehl/mainboard.c b/src/mainboard/siemens/mc_ehl/mainboard.c
index e64dbda..eff2d21 100644
--- a/src/mainboard/siemens/mc_ehl/mainboard.c
+++ b/src/mainboard/siemens/mc_ehl/mainboard.c
@@ -10,6 +10,7 @@
 #include <hwilib.h>
 #include <i210.h>
 #include <soc/gpio.h>
+#include <soc/ramstage.h>
 #include <string.h>
 #include <timer.h>
 #include <timestamp.h>
@@ -114,6 +115,15 @@
 	printk(BIOS_NOTICE, "done!\n");
 }
 
+void mainboard_silicon_init_params(FSP_S_CONFIG *params)
+{
+	/* Disable CPU power states (C-states) */
+	params->Cx = 0;
+
+	/* Set maximum package C-state to PkgC0C1 */
+	params->PkgCStateLimit = 0;
+}
+
 static void mainboard_init(void *chip_info)
 {
 	const struct pad_config *pads;