[coreboot-gerrit] Change in coreboot[master]: mb/google/nipperkin: Fix WLAN to GEN2 speed

[Karthik Ramasubramanian (Code Review)]

Karthik Ramasubramanian has submitted this change. ( https://review.coreboot.org/c/coreboot/+/63722 )

Change subject: mb/google/nipperkin: Fix WLAN to GEN2 speed
......................................................................

mb/google/nipperkin: Fix WLAN to GEN2 speed

Fix WLAN PCIE speed to GEN2. Dynamic switching between speeds is causing
the PSP to hang when resuming from S0ix suspend. The root cause is still
under investigation. Just disabling PSPP fixes the hang but causes poor
PLT performance.

BUG=b:228830362
BRANCH=guybrush
TEST=suspend_stress_test on AC and DC

Change-Id: I988365e51aca0d6515c5605b3032521cf59d8d30
Signed-off-by: Rob Barnes 
Reviewed-on: https://review.coreboot.org/c/coreboot/+/63722
Reviewed-by: Raul Rangel 
Reviewed-by: Kevin Chiu 
Reviewed-by: Karthik Ramasubramanian 
Tested-by: build bot (Jenkins) 
---
M src/mainboard/google/guybrush/variants/nipperkin/variant.c
1 file changed, 9 insertions(+), 3 deletions(-)

Approvals:
  build bot (Jenkins): Verified
  Kevin Chiu: Looks good to me, approved
  Raul Rangel: Looks good to me, approved
  Karthik Ramasubramanian: Looks good to me, approved

diff --git a/src/mainboard/google/guybrush/variants/nipperkin/variant.c b/src/mainboard/google/guybrush/variants/nipperkin/variant.c
index b70545e..48e768d 100644
--- a/src/mainboard/google/guybrush/variants/nipperkin/variant.c
+++ b/src/mainboard/google/guybrush/variants/nipperkin/variant.c
@@ -7,7 +7,13 @@
 {
    dxio_descriptors[WLAN].link_aspm_L1_1 = false;
    dxio_descriptors[WLAN].link_aspm_L1_2 = false;
-	/* Disable PSPP to avoid S0ix hangs - b/228830362 */
-	memset(dxio_descriptors[WLAN].port_params, 0,
-	       sizeof(dxio_descriptors[WLAN].port_params));
+
+	/* Fix link speed to GEN2 - b/228830362 */
+	dxio_descriptors[WLAN].link_speed_capability = GEN2;
+	dxio_descriptors[WLAN].port_params[0] = PP_PSPP_AC;
+	/* AC_DirectIndirect[11:8], AC_MaxPreferredSpeed[7:4], AC_MinPreferredSpeed[3:0] */
+	dxio_descriptors[WLAN].port_params[1] = 0x122;
+	dxio_descriptors[WLAN].port_params[2] = PP_PSPP_DC;
+	/* DC_DirectIndirect[11:8], DC_MaxPreferredSpeed[7:4], DC_MinPreferredSpeed[3:0] */
+	dxio_descriptors[WLAN].port_params[3] = 0x122;
 }