media: atomisp: avoid OOPS due to non-existing ref_frames

stage->args->delay_frames array could point to NULL frames.

What's weird is that we didn't notice this behavior with the
Intel Aero Yocto code.

Handle it, while adding a notice at the code, as this could
be due to some broken pipeline setup.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/staging/media/atomisp/pci/isp/kernels/ref/ref_1.0/ia_css_ref.host.c

@@ -29,10 +29,15 @@ ia_css_ref_config(
 {
 	unsigned int elems_a = ISP_VEC_NELEMS, i;
 
-	(void)size;
-	ia_css_dma_configure_from_info(&to->port_b, &from->ref_frames[0]->info);
-	to->width_a_over_b = elems_a / to->port_b.elems;
-	to->dvs_frame_delay = from->dvs_frame_delay;
+	if (from->ref_frames[0]) {
+		ia_css_dma_configure_from_info(&to->port_b, &from->ref_frames[0]->info);
+		to->width_a_over_b = elems_a / to->port_b.elems;
+		to->dvs_frame_delay = from->dvs_frame_delay;
+	} else {
+		to->width_a_over_b = 1;
+		to->dvs_frame_delay = 0;
+		to->port_b.elems = elems_a;
+	}
 	for (i = 0; i < MAX_NUM_VIDEO_DELAY_FRAMES; i++) {
 		if (from->ref_frames[i]) {
 			to->ref_frame_addr_y[i] = from->ref_frames[i]->data +

drivers/staging/media/atomisp/pci/sh_css_sp.c

@@ -839,6 +839,17 @@ configure_isp_from_args(
 	ia_css_dvs_configure(binary, &args->out_frame[0]->info);
 	ia_css_output_configure(binary, &args->out_frame[0]->info);
 	ia_css_raw_configure(pipeline, binary, &args->in_frame->info, &binary->in_frame_info, two_ppc, deinterleaved);
+
+	/*
+	 * FIXME: args->delay_frames can be NULL here
+	 *
+	 * Somehow, the driver at the Intel Atom Yocto tree doesn't seem to
+	 * suffer from the same issue.
+	 *
+	 * Anyway, the function below should now handle a NULL delay_frames
+	 * without crashing, but the pipeline should likely be built without
+	 * adding it at the first place (or there are a hidden bug somewhere)
+	 */
 	ia_css_ref_configure(binary, args->delay_frames, pipeline->dvs_frame_delay);
 	ia_css_tnr_configure(binary, args->tnr_frames);
 	ia_css_bayer_io_config(binary, args);