drm/xe: move the lmem verification code into a separate function

If lmem (VRAM) is not fully initialized, the punit will power down
the GT, which will prevent register access from the driver side.
That code moved into a corresponding function (xe_verify_lmem_ready)
to make the code clearer.

Signed-off-by: Koby Elbaz <kelbaz@habana.ai>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://lore.kernel.org/r/20231029175326.626745-1-kelbaz@habana.ai
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

drivers/gpu/drm/xe/xe_mmio.c

@@ -381,10 +381,27 @@ static void mmio_fini(struct drm_device *drm, void *arg)
 		iounmap(xe->mem.vram.mapping);
 }
 
+static int xe_verify_lmem_ready(struct xe_device *xe)
+{
+	struct xe_gt *gt = xe_root_mmio_gt(xe);
+
+	/*
+	 * The boot firmware initializes local memory and assesses its health.
+	 * If memory training fails, the punit will have been instructed to
+	 * keep the GT powered down; we won't be able to communicate with it
+	 * and we should not continue with driver initialization.
+	 */
+	if (IS_DGFX(xe) && !(xe_mmio_read32(gt, GU_CNTL) & LMEM_INIT)) {
+		drm_err(&xe->drm, "VRAM not initialized by firmware\n");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
 int xe_mmio_init(struct xe_device *xe)
 {
 	struct xe_tile *root_tile = xe_device_get_root_tile(xe);
-	struct xe_gt *gt = xe_root_mmio_gt(xe);
 	const int mmio_bar = 0;
 	int err;
 
@@ -409,16 +426,9 @@ int xe_mmio_init(struct xe_device *xe)
 	root_tile->mmio.size = xe->mmio.size;
 	root_tile->mmio.regs = xe->mmio.regs;
 
-	/*
-	 * The boot firmware initializes local memory and assesses its health.
-	 * If memory training fails, the punit will have been instructed to
-	 * keep the GT powered down; we won't be able to communicate with it
-	 * and we should not continue with driver initialization.
-	 */
-	if (IS_DGFX(xe) && !(xe_mmio_read32(gt, GU_CNTL) & LMEM_INIT)) {
-		drm_err(&xe->drm, "VRAM not initialized by firmware\n");
-		return -ENODEV;
-	}
+	err = xe_verify_lmem_ready(xe);
+	if (err)
+		return err;
 
 	err = xe_set_dma_info(xe);
 	if (err)