drm/xe: add a flag to bypass multi-tile config from MTCFG reg

Skip reading this register as it is not relevant in the new devices.
Signed-off-by: Koby Elbaz <kelbaz@habana.ai>
Reviewed-by: Ofir Bitton <obitton@habana.ai>
Reviewed-by: Moti Haimovski <mhaimovski@habana.ai>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

drivers/gpu/drm/xe/xe_device_types.h

@@ -243,6 +243,8 @@ struct xe_device {
 		u8 has_llc:1;
 		/** @has_range_tlb_invalidation: Has range based TLB invalidations */
 		u8 has_range_tlb_invalidation:1;
+		/** @bypass_mtcfg: Bypass Multi-Tile configuration from MTCFG register */
+		u8 bypass_mtcfg:1;
 	} info;
 
 	/** @irq: device interrupt state */

drivers/gpu/drm/xe/xe_mmio.c

@@ -318,26 +318,28 @@ int xe_mmio_probe_vram(struct xe_device *xe)
 
 static void xe_mmio_probe_tiles(struct xe_device *xe)
 {
+	u8 adj_tile_count = xe->info.tile_count;
 	struct xe_gt *gt = xe_root_mmio_gt(xe);
 	u32 mtcfg;
-	u8 adj_tile_count;
 	u8 id;
 
 	if (xe->info.tile_count == 1)
 		return;
 
-	mtcfg = xe_mmio_read64_2x32(gt, XEHP_MTCFG_ADDR);
-	adj_tile_count = xe->info.tile_count =
-		REG_FIELD_GET(TILE_COUNT, mtcfg) + 1;
+	if (!xe->info.bypass_mtcfg) {
+		mtcfg = xe_mmio_read64_2x32(gt, XEHP_MTCFG_ADDR);
+		adj_tile_count = xe->info.tile_count =
+			REG_FIELD_GET(TILE_COUNT, mtcfg) + 1;
 
-	/*
-	 * FIXME: Needs some work for standalone media, but should be impossible
-	 * with multi-tile for now.
-	 */
-	xe->info.gt_count = xe->info.tile_count;
+		/*
+		 * FIXME: Needs some work for standalone media, but should be impossible
+		 * with multi-tile for now.
+		 */
+		xe->info.gt_count = xe->info.tile_count;
 
-	drm_info(&xe->drm, "tile_count: %d, adj_tile_count %d\n",
-		 xe->info.tile_count, adj_tile_count);
+		drm_info(&xe->drm, "tile_count: %d, adj_tile_count %d\n",
+			 xe->info.tile_count, adj_tile_count);
+	}
 
 	if (xe->info.tile_count > 1) {
 		const int mmio_bar = 0;

drivers/gpu/drm/xe/xe_pci.c

@@ -56,6 +56,7 @@ struct xe_device_desc {
 	u8 require_force_probe:1;
 	u8 is_dgfx:1;
 	u8 has_llc:1;
+	u8 bypass_mtcfg:1;
 };
 
 #define PLATFORM(x)		\
@@ -553,6 +554,7 @@ static int xe_info_init(struct xe_device *xe,
 	xe->info.graphics_name = graphics_desc->name;
 	xe->info.media_name = media_desc ? media_desc->name : "none";
 	xe->info.has_llc = desc->has_llc;
+	xe->info.bypass_mtcfg = desc->bypass_mtcfg;
 
 	xe->info.dma_mask_size = graphics_desc->dma_mask_size;
 	xe->info.vram_flags = graphics_desc->vram_flags;