[PATCH v3 3/6] spl: LOAD_FIT_FULL: Relocate FDT for u-boot payloads

[Alexandru Gagniuc]

U-Boot expects the FDT to be located right after the _end
linker symbol (see fdtdec.c: board_fdt_blob_setup())

The "basic" LOAD_FIT path is aware of this limitation, and relocates
the FDT at the expected location. Guessing the expected location
probably only works reliably on 32-bit arm, and it feels like a hack.
One proposal would be to pass the FDT address to u-boot
(e.g. using 'r2' on arm platforms).

The variable is named "fdt_hack" to remind future contributors that,
"hey! we should fix the underlying problem". However, that is beyond
the scope of this patch.

Signed-off-by: Alexandru Gagniuc <mr.nuke.me at gmail.com>
---
 common/spl/spl.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/common/spl/spl.c b/common/spl/spl.c
index f3b4c3a036..5a059c6dc5 100644
--- a/common/spl/spl.c
+++ b/common/spl/spl.c
@@ -201,6 +201,7 @@ static int spl_load_fit_image(struct spl_image_info *spl_image,
 {
 	bootm_headers_t images;
 	const char *fit_uname_config = NULL;
+	uintptr_t fdt_hack;
 	const char *uname;
 	ulong fw_data = 0, dt_data = 0, img_data = 0;
 	ulong fw_len = 0, dt_len = 0, img_len = 0;
@@ -233,9 +234,18 @@ static int spl_load_fit_image(struct spl_image_info *spl_image,
 	ret = fit_image_load(&images, (ulong)header, NULL, &fit_uname_config,
 		       IH_ARCH_DEFAULT, IH_TYPE_FLATDT, -1,
 		       FIT_LOAD_OPTIONAL, &dt_data, &dt_len);
-	if (ret >= 0)
+	if (ret >= 0) {
 		spl_image->fdt_addr = (void *)dt_data;
 
+		if (spl_image->os == IH_OS_U_BOOT) {
+			/* HACK: U-boot expects FDT at a specific address */
+			fdt_hack = spl_image->load_addr + spl_image->size;
+			fdt_hack = (fdt_hack + 3) & ~3;
+			debug("Relocating FDT to %p\n", spl_image->fdt_addr);
+			memcpy((void *)fdt_hack, spl_image->fdt_addr, dt_len);
+		}
+	}
+
 	conf_noffset = fit_conf_get_node((const void *)header,
 					 fit_uname_config);
 	if (conf_noffset <= 0)
-- 
2.26.3