drm/xe: Assign GT IDs properly on multi-tile + multi-GT platforms

Although "multi-tile" and "multiple GTs per tile" are mutually-exclusive
characteristics on all of our platforms today, this may not always be
true.  Assign GT IDs according to xe->info.max_gt_per_tile in a way that
should work even if future platforms have different configurations.

This patch should not change the behavior of current platforms; it only
future-proofs for potential future designs.

v2:
 - Re-calculate gt_count if tile count gets reduced by MTCFG.  (PVC CI)

Reviewed-by: Ravi Kumar Vodapalli <ravi.kumar.vodapalli@intel.com>
Link: https://lore.kernel.org/r/20250701201320.2514369-14-matthew.d.roper@intel.com
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>

Author: mattrope

drivers/gpu/drm/xe/xe_mmio.c

@@ -55,6 +55,7 @@ static void tiles_fini(void *arg)
 static void mmio_multi_tile_setup(struct xe_device *xe, size_t tile_mmio_size)
 {
 	struct xe_tile *tile;
+	struct xe_gt *gt;
 	u8 id;
 
 	/*
@@ -67,7 +68,7 @@ static void mmio_multi_tile_setup(struct xe_device *xe, size_t tile_mmio_size)
 	/* Possibly override number of tile based on configuration register */
 	if (!xe->info.skip_mtcfg) {
 		struct xe_mmio *mmio = xe_root_tile_mmio(xe);
-		u8 tile_count;
+		u8 tile_count, gt_count;
 		u32 mtcfg;
 
 		/*
@@ -84,12 +85,15 @@ static void mmio_multi_tile_setup(struct xe_device *xe, size_t tile_mmio_size)
 			xe->info.tile_count = tile_count;
 
 			/*
-			 * FIXME: Needs some work for standalone media, but
-			 * should be impossible with multi-tile for now:
-			 * multi-tile platform with standalone media doesn't
-			 * exist
+			 * We've already setup gt_count according to the full
+			 * tile count.  Re-calculate it to only include the GTs
+			 * that belong to the remaining tile(s).
 			 */
-			xe->info.gt_count = xe->info.tile_count;
+			gt_count = 0;
+			for_each_gt(gt, xe, id)
+				if (gt->info.id < tile_count * xe->info.max_gt_per_tile)
+					gt_count++;
+			xe->info.gt_count = gt_count;
 		}
 	}
 

drivers/gpu/drm/xe/xe_pci.c

@@ -689,10 +689,11 @@ static int xe_info_init(struct xe_device *xe,
 	 */
 	for_each_tile(tile, xe, id) {
 		gt = tile->primary_gt;
-		gt->info.id = xe->info.gt_count++;
 		gt->info.type = XE_GT_TYPE_MAIN;
+		gt->info.id = tile->id * xe->info.max_gt_per_tile;
 		gt->info.has_indirect_ring_state = graphics_desc->has_indirect_ring_state;
 		gt->info.engine_mask = graphics_desc->hw_engine_mask;
+		xe->info.gt_count++;
 
 		if (MEDIA_VER(xe) < 13 && media_desc)
 			gt->info.engine_mask |= media_desc->hw_engine_mask;
@@ -710,17 +711,10 @@ static int xe_info_init(struct xe_device *xe,
 
 		gt = tile->media_gt;
 		gt->info.type = XE_GT_TYPE_MEDIA;
+		gt->info.id = tile->id * xe->info.max_gt_per_tile + 1;
 		gt->info.has_indirect_ring_state = media_desc->has_indirect_ring_state;
 		gt->info.engine_mask = media_desc->hw_engine_mask;
-
-		/*
-		 * FIXME: At the moment multi-tile and standalone media are
-		 * mutually exclusive on current platforms.  We'll need to
-		 * come up with a better way to number GTs if we ever wind
-		 * up with platforms that support both together.
-		 */
-		drm_WARN_ON(&xe->drm, id != 0);
-		gt->info.id = xe->info.gt_count++;
+		xe->info.gt_count++;
 	}
 
 	return 0;