spl: fit: Add support for applying DT overlay

doc/uImage.FIT/overlay-fdt-boot.txt is describing how to create FIT
image with DT overlays in it.
Add support for this feature to SPL.

Here is the ZynqMP fragment where dtb points to full DT and dtbo is
overlay which should be applied on the top of dtb.
config {
        description = "ATF with full u-boot overlay";
        firmware = "atf";
        loadables = "uboot";
        fdt = "dtb", "dtbo";
};

The whole feature depends on OF_LIBFDT_OVERLAY which is adding +4kB code
and 0 for platforms which are not enabling this feature.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

1 files changed, 27 insertions, 3 deletions

diff --git a/common/spl/spl_fit.c b/common/spl/spl_fit.c
index 346f9edaa5..39e406b237 100644
--- a/common/spl/spl_fit.c
+++ b/common/spl/spl_fit.c
@@ -281,7 +281,7 @@ static int spl_fit_append_fdt(struct spl_image_info *spl_image,
 			      void *fit, int images, ulong base_offset)
 {
 	struct spl_image_info image_info;
-	int node, ret = 0;
+	int node, ret = 0, index = 0;
 
 	/*
 	 * Use the address following the image as target address for the
@@ -290,7 +290,7 @@ static int spl_fit_append_fdt(struct spl_image_info *spl_image,
 	image_info.load_addr = spl_image->load_addr + spl_image->size;
 
 	/* Figure out which device tree the board wants to use */
-	node = spl_fit_get_image_node(fit, images, FIT_FDT_PROP, 0);
+	node = spl_fit_get_image_node(fit, images, FIT_FDT_PROP, index++);
 	if (node < 0) {
 		debug("%s: cannot find FDT node\n", __func__);
 
@@ -315,8 +315,32 @@ static int spl_fit_append_fdt(struct spl_image_info *spl_image,
 #if !CONFIG_IS_ENABLED(FIT_IMAGE_TINY)
 	/* Try to make space, so we can inject details on the loadables */
 	ret = fdt_shrink_to_minimum(spl_image->fdt_addr, 8192);
+	if (ret < 0)
+		return ret;
 #endif
-
+	if (CONFIG_IS_ENABLED(LOAD_FIT_APPLY_OVERLAY)) {
+		for (; ; index++) {
+			node = spl_fit_get_image_node(fit, images, FIT_FDT_PROP,
+						      index);
+			if (node < 0) {
+				debug("%s: No additional FDT node\n", __func__);
+				return 0;
+			}
+
+			ret = spl_load_fit_image(info, sector, fit, base_offset,
+						 node, &image_info);
+			if (ret < 0)
+				return ret;
+
+			ret = fdt_overlay_apply_verbose(spl_image->fdt_addr,
+							(void *)image_info.load_addr);
+			if (ret)
+				return ret;
+
+			debug("%s: DT overlay %s applied\n", __func__,
+			      fit_get_name(fit, node, NULL));
+		}
+	}
 	return ret;
 }