soc/intel/skl: always enable SataPwrOptEnable

For unknown reasons FSP skips a whole bunch of SIR (SATA Initialization
Registers) when SataPwrOptEnable=0, which currently is the default in
coreboot and FSP. Even if FSP's default was 1, coreboot would reset it.

This can lead to all sorts of problems and errors, for example:
 - links get lost
 - only 1.5 or 3 Gbps instead of 6 Gbps
 - "unaligned write" errors in Linux
 - ...

At least on two boards (supermicro/x11-lga1151-series/x11ssm-f and
purism/librem13v2) SATA is not working correctly and showing such
symptoms.

To let FSP correctly initialize the SATA controller, enable the option
SataPwrOptEnable statically. There is no valid reason to disable it,
which might break SATA, anyway.

Currently, there are no reported issues on CML and CNL, so a change
there could not be tested reliably. SKL/KBL was tested successfully
without any noticable downsides. Thus, only SKL gets changed for now.

Change-Id: I8531ba9743453a3118b389565517eb769b5e7929
Signed-off-by: Michael Niewöhner <foss@mniewoehner.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/40877
Reviewed-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

2 files changed, 7 insertions, 4 deletions

diff --git a/src/soc/intel/skylake/chip.c b/src/soc/intel/skylake/chip.c
index b731baff8d..b24ec4fdc0 100644
--- a/src/soc/intel/skylake/chip.c
+++ b/src/soc/intel/skylake/chip.c
@@ -258,9 +258,15 @@ void platform_fsp_silicon_init_params_cb(FSPS_UPD *supd)
 	params->SataEnable = config->EnableSata;
 	params->SataMode = config->SataMode;
 	params->SataSpeedLimit = config->SataSpeedLimit;
-	params->SataPwrOptEnable = config->SataPwrOptEnable;
 	params->EnableTcoTimer = !config->PmTimerDisabled;
 
+	/*
+	 * For unknown reasons FSP skips writing some essential SATA init registers (SIR) when
+	 * SataPwrOptEnable=0. This results in link errors, "unaligned write" errors and others.
+	 * Enabling this option solves these problems.
+	 */
+	params->SataPwrOptEnable = 1;
+
 	tconfig->PchLockDownGlobalSmi = config->LockDownConfigGlobalSmi;
 	tconfig->PchLockDownRtcLock = config->LockDownConfigRtcLock;
 	tconfig->PowerLimit4 = config->PowerLimit4;
diff --git a/src/soc/intel/skylake/chip.h b/src/soc/intel/skylake/chip.h
index 387bd6fe3d..d268eebd66 100644
--- a/src/soc/intel/skylake/chip.h
+++ b/src/soc/intel/skylake/chip.h
@@ -567,9 +567,6 @@ struct soc_intel_skylake_config {
 	 */
 	u8 IslVrCmd;
 
-	/* Enable/Disable Sata power optimization */
-	u8 SataPwrOptEnable;
-
 	/* Enable/Disable Sata test mode */
 	u8 SataTestMode;