soc/intel/cannonlake: Ignore GBE LTR

Ignore integrated GBE controller LTR setting to make it wake up from
s0ix with 10/100M cable attached.

BUG=b:122435844
TEST= Test on sarien platorm, after the changes sytem can wake by WOL,
and also checked SLP_S0 residency can increase with 10/100M cable
and battery connected.

Signed-off-by: Lijian Zhao <lijian.zhao@intel.com>
Change-Id: Iec7dd197b8a456751f8e4dcb19e3e153f5888613
Reviewed-on: https://review.coreboot.org/c/coreboot/+/31888
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>

src/soc/intel/cannonlake/fsp_params.c

@@ -107,6 +107,17 @@ static void parse_devicetree(FSP_S_CONFIG *params)
 	parse_devicetree_param(config, params);
 }
 
+/* Ignore LTR value for GBE devices */
+static void ignore_gbe_ltr(void)
+{
+	uint8_t reg8;
+	uint8_t *pmcbase = pmc_mmio_regs();
+
+	reg8 = read8(pmcbase + LTR_IGN);
+	reg8 |= IGN_GBE;
+	write8(pmcbase + LTR_IGN, reg8);
+}
+
 /* UPD parameters to be initialized before SiliconInit */
 void platform_fsp_silicon_init_params_cb(FSPS_UPD *supd)
 {
@@ -168,6 +179,7 @@ void platform_fsp_silicon_init_params_cb(FSPS_UPD *supd)
 			params->PchPmSlpS0VmRuntimeControl = 0;
 			params->PchPmSlpS0Vm070VSupport = 0;
 			params->PchPmSlpS0Vm075VSupport = 0;
+			ignore_gbe_ltr();
 		}
 	}
 

src/soc/intel/cannonlake/include/soc/pmc.h

@@ -145,6 +145,9 @@
 #define   GBLRST_CAUSE0_THERMTRIP	(1 << 5)
 #define GBLRST_CAUSE1			0x1928
 
+#define LTR_IGN				0x1B0C
+#define   IGN_GBE			(1 << 3)
+
 #define CPPMVRIC			0x1B1C
 #define   XTALSDQDIS			(1 << 22)