[U-Boot] [PATCH 6/9] spl: Add support for overlaying U-Boot DT

[Marek Vasut <marex@denx.de>]

Add support for loading fitImage with device tree overlay image, which
is applied to the U-Boot's own device tree. Once the DT is applied, the
fitImage loading process is restarted.

This patch allows a usecase where the DTO patches ie. load address in
the U-Boot's DT or patches in a new public key for authenticating the
subsequently loaded fitImages.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Cc: Simon Glass <sjg@chromium.org>
---
 common/spl/spl.c | 38 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 37 insertions(+), 1 deletion(-)

diff --git a/common/spl/spl.c b/common/spl/spl.c
index d429ea2c82..2444abbb08 100644
--- a/common/spl/spl.c
+++ b/common/spl/spl.c
@@ -140,6 +140,38 @@ void spl_set_header_raw_uboot(struct spl_image_info *spl_image)
 }
 
 #ifdef CONFIG_SPL_LOAD_FIT_FULL
+#ifdef CONFIG_OF_LIBFDT_OVERLAY
+static int spl_fit_overlay_uboot_fdt_full(const struct image_header *header)
+{
+	bootm_headers_t images;
+	const char *fit_uname_config = NULL;
+	const char *fit_uname_dtbo = "u-boot-dtbo";
+	ulong dto_data = 0;
+	ulong dto_len = 0;
+	int ret;
+
+	ret = fit_image_load(&images, (ulong)header,
+			     &fit_uname_dtbo, &fit_uname_config,
+			     IH_ARCH_DEFAULT, IH_TYPE_FLATDT, -1,
+			     FIT_LOAD_OPTIONAL, &dto_data, &dto_len);
+	if (ret < 0)
+		return 0;
+
+	ret = fdt_overlay_apply_verbose((struct fdt_header *)gd->fdt_blob,
+					(void *)dto_data);
+	if (ret)
+		hang();
+
+	/* Restart the loading process to cater for the DT changes */
+	return -EAGAIN;
+}
+#else
+static int spl_fit_overlay_uboot_fdt_full(const struct image_header *header)
+{
+	return 0;
+}
+#endif
+
 /* Parse and load full fitImage in SPL */
 static int spl_load_fit_image(struct spl_image_info *spl_image,
 			      const struct image_header *header)
@@ -152,6 +184,10 @@ static int spl_load_fit_image(struct spl_image_info *spl_image,
 	ulong fw_len = 0, dt_len = 0;
 	int ret;
 
+	ret = spl_fit_overlay_uboot_fdt_full(header);
+	if (ret)
+		return ret;
+
 	ret = fit_image_load(&images, (ulong)header,
 			     NULL, &fit_uname_config,
 			     IH_ARCH_DEFAULT, IH_TYPE_STANDALONE, -1,
@@ -182,7 +218,7 @@ int spl_parse_image_header(struct spl_image_info *spl_image,
 {
 #ifdef CONFIG_SPL_LOAD_FIT_FULL
 	int ret = spl_load_fit_image(spl_image, header);
-	if (!ret)
+	if (!ret || ret == -EAGAIN)
 		return ret;
 #endif
 	if (image_get_magic(header) == IH_MAGIC) {
-- 
2.15.0