media: mediatek: vcodec: Handle invalid decoder vsi

Handle an invalid decoder vsi in vpu_dec_init to ensure the decoder vsi
is valid for future use.

Fixes: 590577a4 ("[media] vcodec: mediatek: Add Mediatek V4L2 Video Decoder Driver")
Signed-off-by: Irui Wang <irui.wang@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Sebastian Fricke <sebastian.fricke@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

drivers/media/platform/mediatek/vcodec/decoder/vdec_vpu_if.c

@@ -233,6 +233,12 @@ int vpu_dec_init(struct vdec_vpu_inst *vpu)
 	mtk_vdec_debug(vpu->ctx, "vdec_inst=%p", vpu);
 
 	err = vcodec_vpu_send_msg(vpu, (void *)&msg, sizeof(msg));
+
+	if (IS_ERR_OR_NULL(vpu->vsi)) {
+		mtk_vdec_err(vpu->ctx, "invalid vdec vsi, status=%d", err);
+		return -EINVAL;
+	}
+
 	mtk_vdec_debug(vpu->ctx, "- ret=%d", err);
 	return err;
 }