test: overlay: Add unit test for stacked overlay

Verify that stacked overlays work.

Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Acked-by: Simon Glass <sjg@chromium.org>

test/overlay/Makefile

@@ -13,3 +13,4 @@ DTC_FLAGS += -@
 # DT overlays
 obj-y += test-fdt-base.dtb.o
 obj-y += test-fdt-overlay.dtb.o
+obj-y += test-fdt-overlay-stacked.dtb.o

test/overlay/cmd_ut_overlay.c

@@ -20,6 +20,7 @@
 
 extern u32 __dtb_test_fdt_base_begin;
 extern u32 __dtb_test_fdt_overlay_begin;
+extern u32 __dtb_test_fdt_overlay_stacked_begin;
 
 static int ut_fdt_getprop_u32_by_index(void *fdt, const char *path,
 				    const char *name, int index,
@@ -201,6 +202,19 @@ static int fdt_overlay_local_phandles(struct unit_test_state *uts)
 }
 OVERLAY_TEST(fdt_overlay_local_phandles, 0);
 
+static int fdt_overlay_stacked(struct unit_test_state *uts)
+{
+	void *fdt = uts->priv;
+	u32 val = 0;
+
+	ut_assertok(ut_fdt_getprop_u32(fdt, "/new-local-node",
+				       "stacked-test-int-property", &val));
+	ut_asserteq(43, val);
+
+	return CMD_RET_SUCCESS;
+}
+OVERLAY_TEST(fdt_overlay_stacked, 0);
+
 int do_ut_overlay(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
 	struct unit_test *tests = ll_entry_start(struct unit_test,
@@ -210,7 +224,8 @@ int do_ut_overlay(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 	struct unit_test *test;
 	void *fdt_base = &__dtb_test_fdt_base_begin;
 	void *fdt_overlay = &__dtb_test_fdt_overlay_begin;
-	void *fdt_base_copy, *fdt_overlay_copy;
+	void *fdt_overlay_stacked = &__dtb_test_fdt_overlay_stacked_begin;
+	void *fdt_base_copy, *fdt_overlay_copy, *fdt_overlay_stacked_copy;
 
 	uts = calloc(1, sizeof(*uts));
 	if (!uts)
@@ -228,6 +243,10 @@ int do_ut_overlay(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 	if (!fdt_overlay_copy)
 		return -ENOMEM;
 
+	fdt_overlay_stacked_copy = malloc(FDT_COPY_SIZE);
+	if (!fdt_overlay_stacked_copy)
+		return -ENOMEM;
+
 	/*
 	 * Resize the FDT to 4k so that we have room to operate on
 	 *
@@ -245,9 +264,21 @@ int do_ut_overlay(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 	ut_assertok(fdt_open_into(fdt_overlay, fdt_overlay_copy,
 				  FDT_COPY_SIZE));
 
+	/*
+	 * Resize the stacked overlay to 4k so that we have room to operate on
+	 *
+	 * (and relocate it since the memory might be mapped
+	 * read-only)
+	 */
+	ut_assertok(fdt_open_into(fdt_overlay_stacked, fdt_overlay_stacked_copy,
+				  FDT_COPY_SIZE));
+
 	/* Apply the overlay */
 	ut_assertok(fdt_overlay_apply(fdt_base_copy, fdt_overlay_copy));
 
+	/* Apply the stacked overlay */
+	ut_assertok(fdt_overlay_apply(fdt_base_copy, fdt_overlay_stacked_copy));
+
 	if (argc == 1)
 		printf("Running %d environment tests\n", n_ents);
 
@@ -263,6 +294,7 @@ int do_ut_overlay(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 
 	printf("Failures: %d\n", uts->fail_count);
 
+	free(fdt_overlay_stacked_copy);
 	free(fdt_overlay_copy);
 	free(fdt_base_copy);
 	free(uts);

test/overlay/test-fdt-overlay-stacked.dts

@@ -0,0 +1,21 @@
+/*
+ * Copyright (c) 2016 NextThing Co
+ * Copyright (c) 2016 Free Electrons
+ * Copyright (c) 2018 Konsulko Group
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+/dts-v1/;
+/plugin/;
+
+/ {
+	/* Test that we can reference an overlay symbol */
+	fragment@0 {
+		target = <&local>;
+
+		__overlay__ {
+			stacked-test-int-property = <43>;
+		};
+	};
+};