[PATCH 1/7] drm/i915/huc: only load HuC on GTs that have VCS engines

[Daniele Ceraolo Spurio]

On MTL the primary GT doesn't have any media capabilities, so no video
engines and no HuC. We must therefore skip the HuC fetch and load on
that specific case. Given that other multi-GT platforms might have HuC
on the primary GT, we can't just check for that and it is easier to
instead check for the lack of VCS engines.

Based on code from Aravind Iddamsetty

Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
Cc: Aravind Iddamsetty <aravind.iddamsetty at intel.com>
Cc: John Harrison <john.c.harrison at intel.com>
Cc: Alan Previn <alan.previn.teres.alexis at intel.com>
---
 drivers/gpu/drm/i915/gt/uc/intel_huc.c | 21 +++++++++++++++++++++
 drivers/gpu/drm/i915/i915_drv.h        |  9 ++++++---
 2 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/uc/intel_huc.c b/drivers/gpu/drm/i915/gt/uc/intel_huc.c
index 3bb8838e325a..d4e2b252f16c 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_huc.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_huc.c
@@ -42,12 +42,33 @@
  * HuC-specific commands.
  */
 
+static bool vcs_supported(struct intel_gt *gt)
+{
+	intel_engine_mask_t mask = gt->info.engine_mask;
+
+	/*
+	 * we can reach here from i915_driver_early_probe for primary
+	 * GT with it being not fully setup hence fall back to the device info's
+	 * engine mask
+	 */
+	if (!mask && gt_is_root(gt))
+		mask = RUNTIME_INFO(gt->i915)->platform_engine_mask;
+
+	return __ENGINE_INSTANCES_MASK(mask, VCS0, I915_MAX_VCS);
+}
+
 void intel_huc_init_early(struct intel_huc *huc)
 {
 	struct drm_i915_private *i915 = huc_to_gt(huc)->i915;
+	struct intel_gt *gt = huc_to_gt(huc);
 
 	intel_uc_fw_init_early(&huc->fw, INTEL_UC_FW_TYPE_HUC);
 
+	if (!vcs_supported(gt)) {
+		intel_uc_fw_change_status(&huc->fw, INTEL_UC_FIRMWARE_NOT_SUPPORTED);
+		return;
+	}
+
 	if (GRAPHICS_VER(i915) >= 11) {
 		huc->status.reg = GEN11_HUC_KERNEL_LOAD_INFO;
 		huc->status.mask = HUC_LOAD_SUCCESSFUL;
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 134fc1621821..8ca575202e5d 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -777,12 +777,15 @@ IS_SUBPLATFORM(const struct drm_i915_private *i915,
 #define __HAS_ENGINE(engine_mask, id) ((engine_mask) & BIT(id))
 #define HAS_ENGINE(gt, id) __HAS_ENGINE((gt)->info.engine_mask, id)
 
-#define ENGINE_INSTANCES_MASK(gt, first, count) ({		\
+#define __ENGINE_INSTANCES_MASK(mask, first, count) ({			\
 	unsigned int first__ = (first);					\
 	unsigned int count__ = (count);					\
-	((gt)->info.engine_mask &						\
-	 GENMASK(first__ + count__ - 1, first__)) >> first__;		\
+	((mask) & GENMASK(first__ + count__ - 1, first__)) >> first__;	\
 })
+
+#define ENGINE_INSTANCES_MASK(gt, first, count) \
+	__ENGINE_INSTANCES_MASK((gt)->info.engine_mask, first, count)
+
 #define RCS_MASK(gt) \
 	ENGINE_INSTANCES_MASK(gt, RCS0, I915_MAX_RCS)
 #define BCS_MASK(gt) \
-- 
2.37.3