drm/i915/xehp: Enable ccs/dual-ctx in RCU_MODE

We have to specify in the Render Control Unit Mode register
when CCS is enabled.

v2:
 - Move RCU_MODE programming to a helper function.  (Tvrtko)
 - Clean up and clarify comments.  (Tvrtko)
 - Add RCU_MODE to the GuC save/restore list.  (Daniele)
v3:
 - Move this patch before the GuC ADS update to enable compute engines;
   the definition of RCU_MODE and its insertion into the save/restore
   list moves to this patch.  (Daniele)
v4:
 - Call xehp_enable_ccs_engines() directly in guc_resume() and
   execlists_resume() rather than adding an extra layer of wrapping to
   the engine->resume() vfunc.  (Umesh)

Bspec: 46034
Original-author: Michel Thierry
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Cc: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Aravind Iddamsetty <aravind.iddamsetty@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220302001554.1836066-1-matthew.d.roper@intel.com

1 files changed, 17 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
index 2136c56d3abc..92f4cf9833ee 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
@@ -2070,6 +2070,23 @@ intel_engine_execlist_find_hung_request(struct intel_engine_cs *engine)
 	return active;
 }
 
+void xehp_enable_ccs_engines(struct intel_engine_cs *engine)
+{
+	/*
+	 * If there are any non-fused-off CCS engines, we need to enable CCS
+	 * support in the RCU_MODE register.  This only needs to be done once,
+	 * so for simplicity we'll take care of this in the RCS engine's
+	 * resume handler; since the RCS and all CCS engines belong to the
+	 * same reset domain and are reset together, this will also take care
+	 * of re-applying the setting after i915-triggered resets.
+	 */
+	if (!CCS_MASK(engine->gt))
+		return;
+
+	intel_uncore_write(engine->uncore, GEN12_RCU_MODE,
+			   _MASKED_BIT_ENABLE(GEN12_RCU_MODE_CCS_ENABLE));
+}
+
 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
 #include "mock_engine.c"
 #include "selftest_engine.c"