[U-Boot] [RFC PATCH v2 01/12] spl: fit: Add support for applying DT overlay

[Jean-Jacques Hiblot]

From: Michal Simek <michal.simek at xilinx.com>

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 at xilinx.com>
Signed-off-by: Jean-Jacques Hiblot <jjhiblot at ti.com>
---

Changes in v2: None

 common/spl/spl_fit.c | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/common/spl/spl_fit.c b/common/spl/spl_fit.c
index c9bfe0cc8a..6b71de73e7 100644
--- a/common/spl/spl_fit.c
+++ b/common/spl/spl_fit.c
@@ -278,10 +278,10 @@ 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;
+	int node, ret, index = 0;
 
 	/* 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__);
 		return node;
@@ -303,8 +303,31 @@ 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 defined(CONFIG_OF_LIBFDT_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));
+	}
+#endif
 	return ret;
 }
 
-- 
2.17.1