[Intel-gfx] [PATCH v2] drm/i915/guc: fix mmio whitelist mmio_start offset and add reminder

[Daniele Ceraolo Spurio]

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.

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>
---
 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 beec88a..c689fe5 100644
--- a/drivers/gpu/drm/i915/i915_guc_submission.c
+++ b/drivers/gpu/drm/i915/i915_guc_submission.c
@@ -852,10 +852,17 @@ static void guc_addon_create(struct intel_guc *guc)
 
 	for_each_engine(engine, dev_priv, id) {
 		reg_state->mmio_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.
+		 */
 		reg_state->mmio_white_list[engine->guc_id].count = 0;
+
+		/* Nothing to be saved or restored for now. */
 	}
 
 	ads->reg_state_addr = ads->scheduler_policies +
diff --git a/drivers/gpu/drm/i915/intel_guc_fwif.h b/drivers/gpu/drm/i915/intel_guc_fwif.h
index 25691f0..da7dcac 100644
--- a/drivers/gpu/drm/i915/intel_guc_fwif.h
+++ b/drivers/gpu/drm/i915/intel_guc_fwif.h
@@ -386,7 +386,6 @@ 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
 
-- 
1.9.1