[PATCH 2/2] efi: loader: remove dependency on LIBFDT

[Ahmad Fatoum]

LIBFDT is often available, because CONFIG_BOARD_GENERIC_DT pulls it in,
but in the normal case, we unflatten DT and have no need for libfdt at
all.

Remove the libfdt dependency from the EFI loader code by opencoding the
magic check.

Fixes: 229bc3b37e64 ("efi: loader: implement bootm handler")
Reported-by: Leonard Göhrs <l.goe...@pengutronix.de>
Signed-off-by: Ahmad Fatoum <a.fat...@barebox.org>
---
 efi/loader/bootm.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/efi/loader/bootm.c b/efi/loader/bootm.c
index dffe53bcf9c8..da664847def8 100644
--- a/efi/loader/bootm.c
+++ b/efi/loader/bootm.c
@@ -124,15 +124,20 @@ static efi_status_t copy_fdt(void **fdtp)
  */
 static efi_status_t efi_install_fdt(void *fdt)
 {
+       const struct fdt_header *hdr = fdt;
        /*
         * The EBBR spec requires that we have either an FDT or an ACPI table
         * but not both.
         */
        efi_status_t ret;
 
-       /* Install device tree */
-       if (fdt_check_header(fdt)) {
-               pr_err("invalid device tree\n");
+       if (hdr->magic != cpu_to_fdt32(FDT_MAGIC)) {
+               pr_err("bad magic: 0x%08x\n", fdt32_to_cpu(hdr->magic));
+               return EFI_LOAD_ERROR;
+       }
+
+       if (hdr->version != cpu_to_fdt32(17)) {
+               pr_err("bad dt version: 0x%08x\n", fdt32_to_cpu(hdr->version));
                return EFI_LOAD_ERROR;
        }
 
-- 
2.47.3