[PATCH 17/25] drm/i915/guc: fix mmio whitelist mmio_start offset and add reminder

[Michel Thierry]

From: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>

The mmio_start offset for the whitelist is the first FORCE_TO_NONPRIV
register the GuC can use to restore the provided whitelist when an
engine reset via GuC (which we still don't support) is triggered.

We're currently adding the mmio_base of the engine to the absolute
address of the RCS version of the register, which results in the wrong
offset. Fix it by using the definition we already have instead of
re-defining it in the GuC FW header.

Also add a comment to avoid future issues with FORCE_TO_NONPRIV
registers, which are also used by the workaround framework.

v2: improve comment (Michal), move comment about save/restore because it
    is not related to the mmio_white_list field.

v3: rebase/resurrect.

Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
Cc: Michał Winiarski <michal.winiarski at intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko at intel.com>
Cc: Arkadiusz Hiler <arkadiusz.hiler at intel.com>
Cc: Oscar Mateo <oscar.mateo at intel.com>
Reviewed-by: Michał Winiarski <michal.winiarski at intel.com> (v2)
Signed-off-by: Michel Thierry <michel.thierry at intel.com>
---
 drivers/gpu/drm/i915/i915_guc_submission.c | 11 +++++++++--
 drivers/gpu/drm/i915/intel_guc_fwif.h      |  1 -
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c
index 4cc97bf1bdac..2cfe5d3b7795 100644
--- a/drivers/gpu/drm/i915/i915_guc_submission.c
+++ b/drivers/gpu/drm/i915/i915_guc_submission.c
@@ -1034,10 +1034,17 @@ static int guc_ads_create(struct intel_guc *guc)
 	/* MMIO reg state */
 	for_each_engine(engine, dev_priv, id) {
 		blob->reg_state.white_list[engine->guc_id].mmio_start =
-			engine->mmio_base + GUC_MMIO_WHITE_LIST_START;
+			i915_mmio_reg_offset(RING_FORCE_TO_NONPRIV(engine->mmio_base, 0));
 
-		/* Nothing to be saved or restored for now. */
+		/*
+		 * Note: if the GuC whitelist management is enabled, the values
+		 * should be filled using the workaround framework to avoid
+		 * inconsistencies with the handling of FORCE_TO_NONPRIV
+		 * registers.
+		 */
 		blob->reg_state.white_list[engine->guc_id].count = 0;
+
+		/* Nothing to be saved or restored for now. */
 	}
 
 	/*
diff --git a/drivers/gpu/drm/i915/intel_guc_fwif.h b/drivers/gpu/drm/i915/intel_guc_fwif.h
index 6156845641a3..e6f8079df94a 100644
--- a/drivers/gpu/drm/i915/intel_guc_fwif.h
+++ b/drivers/gpu/drm/i915/intel_guc_fwif.h
@@ -394,7 +394,6 @@ struct guc_policies {
 #define GUC_REGSET_SAVE_CURRENT_VALUE	0x10
 
 #define GUC_REGSET_MAX_REGISTERS	25
-#define GUC_MMIO_WHITE_LIST_START	0x24d0
 #define GUC_MMIO_WHITE_LIST_MAX		12
 #define GUC_S3_SAVE_SPACE_PAGES		10
 
-- 
2.11.0