This returns a devicetree and updates a parameter with an error code.
Swap it, since this fits better with the way U-Boot normally works. It
also (more easily) allows leaving the existing pointer unchanged.

No yaks were harmed in this change, but there is a very small code-size
reduction.

For sifive, the OF_BOARD option must be set for the function to be
called, so there is no point in checking it again. Also OF_SEPARATE is
defined always.

Signed-off-by: Simon Glass <[email protected]>
---

Changes in v2:
- Set up the existing FDT in case the board wants to check it
- Update snapdragon to return -EEXIST
- Set the existing FDT before calling board_fd_blob_setup()
- Update sandbox to return -EEXIST if an fdt comes from a bloblist
- Update do_go_uboot() to set the existing FDT
- Drop unnecessary setting of FDT in vexpress64
- Tidy up redundant RISC-V code

 arch/arm/mach-apple/board.c                   |  7 ++--
 arch/arm/mach-snapdragon/board.c              |  9 ++---
 arch/arm/mach-stm32mp/boot_params.c           | 19 ++++++-----
 arch/sandbox/cpu/cpu.c                        | 34 +++++++++----------
 board/Marvell/octeontx/board-fdt.c            | 12 +++----
 board/Marvell/octeontx2/board-fdt.c           | 12 +++----
 board/Marvell/octeontx2/board.c               |  3 +-
 board/andestech/ae350/ae350.c                 | 23 +++++++------
 board/armltd/vexpress64/vexpress64.c          | 33 ++++++++----------
 board/broadcom/bcmstb/bcmstb.c                |  7 ++--
 board/emulation/qemu-arm/qemu-arm.c           |  7 ++--
 board/emulation/qemu-ppce500/qemu-ppce500.c   | 12 +++----
 board/emulation/qemu-riscv/qemu-riscv.c       |  7 ++--
 board/highbank/highbank.c                     |  7 ++--
 board/raspberrypi/rpi/rpi.c                   | 13 ++++---
 board/sifive/unleashed/unleashed.c            | 12 +++----
 board/sifive/unmatched/unmatched.c            | 11 +++---
 .../visionfive2/starfive_visionfive2.c        | 11 +++---
 board/xen/xenguest_arm64/xenguest_arm64.c     | 14 ++++----
 board/xilinx/common/board.c                   | 26 ++++++++------
 include/fdtdec.h                              |  9 ++---
 lib/fdtdec.c                                  | 14 +++++---
 22 files changed, 152 insertions(+), 150 deletions(-)

diff --git a/arch/arm/mach-apple/board.c b/arch/arm/mach-apple/board.c
index 0b6d290b8ac..2644a04a622 100644
--- a/arch/arm/mach-apple/board.c
+++ b/arch/arm/mach-apple/board.c
@@ -691,11 +691,12 @@ int dram_init_banksize(void)
 
 extern long fw_dtb_pointer;
 
-void *board_fdt_blob_setup(int *err)
+int board_fdt_blob_setup(void **fdtp)
 {
        /* Return DTB pointer passed by m1n1 */
-       *err = 0;
-       return (void *)fw_dtb_pointer;
+       *fdtp = (void *)fw_dtb_pointer;
+
+       return 0;
 }
 
 void build_mem_map(void)
diff --git a/arch/arm/mach-snapdragon/board.c b/arch/arm/mach-snapdragon/board.c
index 2ab2ceb5138..cd49de540f0 100644
--- a/arch/arm/mach-snapdragon/board.c
+++ b/arch/arm/mach-snapdragon/board.c
@@ -147,12 +147,12 @@ static void show_psci_version(void)
  * or for supporting quirky devices where it's easier to leave the downstream 
DT in place
  * to improve ABL compatibility. Otherwise, we use the DT provided by ABL.
  */
-void *board_fdt_blob_setup(int *err)
+int board_fdt_blob_setup(void **fdtp)
 {
        struct fdt_header *fdt;
        bool internal_valid, external_valid;
+       int ret = 0;
 
-       *err = 0;
        fdt = (struct fdt_header *)get_prev_bl_fdt_addr();
        external_valid = fdt && !fdt_check_header(fdt);
        internal_valid = !fdt_check_header(gd->fdt_blob);
@@ -167,10 +167,11 @@ void *board_fdt_blob_setup(int *err)
 
        if (internal_valid) {
                debug("Using built in FDT\n");
+               ret = -EEXIST;
        } else {
                debug("Using external FDT\n");
                /* So we can use it before returning */
-               gd->fdt_blob = fdt;
+               *fdtp = fdt;
        }
 
        /*
@@ -179,7 +180,7 @@ void *board_fdt_blob_setup(int *err)
         */
        qcom_parse_memory();
 
-       return (void *)gd->fdt_blob;
+       return ret;
 }
 
 void reset_cpu(void)
diff --git a/arch/arm/mach-stm32mp/boot_params.c 
b/arch/arm/mach-stm32mp/boot_params.c
index ebddf6a7dbc..2d058edc419 100644
--- a/arch/arm/mach-stm32mp/boot_params.c
+++ b/arch/arm/mach-stm32mp/boot_params.c
@@ -6,6 +6,7 @@
 #define LOG_CATEGORY LOGC_ARCH
 
 #include <config.h>
+#include <errno.h>
 #include <log.h>
 #include <linux/libfdt.h>
 #include <asm/arch/sys_proto.h>
@@ -16,20 +17,22 @@
  * Use the saved FDT address provided by TF-A at boot time (NT_FW_CONFIG =
  * Non Trusted Firmware configuration file) when the pointer is valid
  */
-void *board_fdt_blob_setup(int *err)
+int board_fdt_blob_setup(void **fdtp)
 {
        unsigned long nt_fw_dtb = get_stm32mp_bl2_dtb();
 
        log_debug("%s: nt_fw_dtb=%lx\n", __func__, nt_fw_dtb);
 
-       *err = 0;
        /* use external device tree only if address is valid */
-       if (nt_fw_dtb >= STM32_DDR_BASE) {
-               if (fdt_magic(nt_fw_dtb) == FDT_MAGIC)
-                       return (void *)nt_fw_dtb;
-               log_debug("%s: DTB not found.\n", __func__);
+       if (nt_fw_dtb < STM32_DDR_BASE ||
+           fdt_magic(nt_fw_dtb) != FDT_MAGIC) {
+               log_debug("DTB not found.\n");
+               log_debug("fall back to builtin DTB, %p\n", _end);
+
+               return -EEXIST;
        }
-       log_debug("%s: fall back to builtin DTB, %p\n", __func__, _end);
 
-       return (void *)_end;
+       *fdtp = (void *)nt_fw_dtb;
+
+       return 0;
 }
diff --git a/arch/sandbox/cpu/cpu.c b/arch/sandbox/cpu/cpu.c
index 06f8c13fab9..a1bcb26e25e 100644
--- a/arch/sandbox/cpu/cpu.c
+++ b/arch/sandbox/cpu/cpu.c
@@ -355,7 +355,7 @@ static int setup_auto_tree(void *blob)
        return 0;
 }
 
-void *board_fdt_blob_setup(int *ret)
+int board_fdt_blob_setup(void **fdtp)
 {
        struct sandbox_state *state = state_get_current();
        const char *fname = state->fdt_fname;
@@ -365,43 +365,41 @@ void *board_fdt_blob_setup(int *ret)
        int fd;
 
        if (gd->fdt_blob)
-               return (void *)gd->fdt_blob;
+               return -EEXIST;
        blob = map_sysmem(CONFIG_SYS_FDT_LOAD_ADDR, 0);
-       *ret = 0;
        if (!state->fdt_fname) {
                err = setup_auto_tree(blob);
-               if (!err)
-                       goto done;
-               os_printf("Unable to create empty FDT: %s\n", 
fdt_strerror(err));
-               *ret = -EINVAL;
-               goto fail;
+               if (err) {
+                       os_printf("Unable to create empty FDT: %s\n",
+                                 fdt_strerror(err));
+                       return -EINVAL;
+               }
+               *fdtp = blob;
+
+               return 0;
        }
 
        err = os_get_filesize(fname, &size);
        if (err < 0) {
                os_printf("Failed to find FDT file '%s'\n", fname);
-               *ret = err;
-               goto fail;
+               return err;
        }
        fd = os_open(fname, OS_O_RDONLY);
        if (fd < 0) {
                os_printf("Failed to open FDT file '%s'\n", fname);
-               *ret = -EACCES;
-               goto fail;
+               return -EACCES;
        }
 
        if (os_read(fd, blob, size) != size) {
                os_close(fd);
                os_printf("Failed to read FDT file '%s'\n", fname);
-               *ret =  -EIO;
-               goto fail;
+               return -EIO;
        }
        os_close(fd);
 
-done:
-       return blob;
-fail:
-       return NULL;
+       *fdtp = blob;
+
+       return 0;
 }
 
 ulong timer_get_boot_us(void)
diff --git a/board/Marvell/octeontx/board-fdt.c 
b/board/Marvell/octeontx/board-fdt.c
index 6642b167e19..9d913b959e0 100644
--- a/board/Marvell/octeontx/board-fdt.c
+++ b/board/Marvell/octeontx/board-fdt.c
@@ -296,13 +296,9 @@ int ft_board_setup(void *blob, struct bd_info *bd)
        return 0;
 }
 
-/**
- * Return the FDT base address that was passed by ATF
- *
- * Return:     FDT base address received from ATF in x1 register
- */
-void *board_fdt_blob_setup(int *err)
+int board_fdt_blob_setup(void **fdtp)
 {
-       *err = 0;
-       return (void *)fdt_base_addr;
+       *fdtp = (void *)fdt_base_addr;
+
+       return 0;
 }
diff --git a/board/Marvell/octeontx2/board-fdt.c 
b/board/Marvell/octeontx2/board-fdt.c
index 04be9fb0a9a..e5a4db00bb7 100644
--- a/board/Marvell/octeontx2/board-fdt.c
+++ b/board/Marvell/octeontx2/board-fdt.c
@@ -210,13 +210,9 @@ int ft_board_setup(void *blob, struct bd_info *bd)
        return 0;
 }
 
-/**
- * Return the FDT base address that was passed by ATF
- *
- * Return:     FDT base address received from ATF in x1 register
- */
-void *board_fdt_blob_setup(int *err)
+int board_fdt_blob_setup(void **fdtp)
 {
-       *err = 0;
-       return (void *)fdt_base_addr;
+       *fdtp = (void *)fdt_base_addr;
+
+       return 0;
 }
diff --git a/board/Marvell/octeontx2/board.c b/board/Marvell/octeontx2/board.c
index 974e9eb8200..01ba53cf68d 100644
--- a/board/Marvell/octeontx2/board.c
+++ b/board/Marvell/octeontx2/board.c
@@ -234,7 +234,8 @@ static int do_go_uboot(struct cmd_tbl *cmdtp, int flag, int 
argc,
                return CMD_RET_USAGE;
 
        addr = hextoul(argv[1], NULL);
-       fdt = board_fdt_blob_setup(&err);
+       fdt = (void *)gd->fdt_blob;
+       err = board_fdt_blob_setup(&fdt);
        entry = (uboot_entry_t)addr;
        flush_cache((ulong)addr, 1 << 20);      /* 1MiB should be enough */
        dcache_disable();
diff --git a/board/andestech/ae350/ae350.c b/board/andestech/ae350/ae350.c
index 5ae5baed6ba..1d9d4a929c2 100644
--- a/board/andestech/ae350/ae350.c
+++ b/board/andestech/ae350/ae350.c
@@ -79,21 +79,24 @@ ulong board_flash_get_legacy(ulong base, int banknum, 
flash_info_t *info)
 }
 
 #define ANDES_HW_DTB_ADDRESS   0xF2000000
-void *board_fdt_blob_setup(int *err)
+int board_fdt_blob_setup(void **fdtp)
 {
-       *err = 0;
-
        if (IS_ENABLED(CONFIG_OF_SEPARATE) || IS_ENABLED(CONFIG_OF_BOARD)) {
-               if (fdt_magic((uintptr_t)gd->arch.firmware_fdt_addr) == 
FDT_MAGIC)
-                       return (void *)(ulong)gd->arch.firmware_fdt_addr;
+               if (fdt_magic((uintptr_t)gd->arch.firmware_fdt_addr) ==
+                       FDT_MAGIC) {
+                       *fdtp = (void *)(ulong)gd->arch.firmware_fdt_addr;
+
+                       return 0;
+               }
        }
 
-       if (fdt_magic(CONFIG_SYS_FDT_BASE) == FDT_MAGIC)
-               return (void *)CONFIG_SYS_FDT_BASE;
-       return (void *)ANDES_HW_DTB_ADDRESS;
+       if (fdt_magic(CONFIG_SYS_FDT_BASE) == FDT_MAGIC) {
+               *fdtp = (void *)CONFIG_SYS_FDT_BASE;
+
+               return 0;
+       }
 
-       *err = -EINVAL;
-       return NULL;
+       return -EINVAL;
 }
 
 #ifdef CONFIG_SPL_BOARD_INIT
diff --git a/board/armltd/vexpress64/vexpress64.c 
b/board/armltd/vexpress64/vexpress64.c
index 0119f54f0df..b5ede58757d 100644
--- a/board/armltd/vexpress64/vexpress64.c
+++ b/board/armltd/vexpress64/vexpress64.c
@@ -168,42 +168,37 @@ static bool is_valid_dtb(uintptr_t dtb_ptr)
        return fdt_subnode_offset((void *)dtb_ptr, 0, "memory") >= 0;
 }
 
-void *board_fdt_blob_setup(int *err)
+int board_fdt_blob_setup(void **fdtp)
 {
 #ifdef CONFIG_TARGET_VEXPRESS64_JUNO
        phys_addr_t fdt_rom_addr = find_dtb_in_nor_flash(CONFIG_JUNO_DTB_PART);
 
-       *err = 0;
-       if (fdt_rom_addr == ~0UL) {
-               *err = -ENXIO;
-               return NULL;
-       }
+       if (fdt_rom_addr == ~0UL)
+               return -ENXIO;
 
-       return (void *)fdt_rom_addr;
+       *fdtp = (void *)fdt_rom_addr;
+       return 0;
 #endif
 
 #ifdef VEXPRESS_FDT_ADDR
        if (fdt_magic(VEXPRESS_FDT_ADDR) == FDT_MAGIC) {
-               *err = 0;
-               return (void *)VEXPRESS_FDT_ADDR;
+               *fdtp = (void *)VEXPRESS_FDT_ADDR;
+               return 0;
        }
 #endif
 
        if (is_valid_dtb(prior_stage_fdt_address[1])) {
-               *err = 0;
-               return (void *)prior_stage_fdt_address[1];
+               *fdtp = (void *)prior_stage_fdt_address[1];
+               return 0;
        } else if (is_valid_dtb(prior_stage_fdt_address[0])) {
-               *err = 0;
-               return (void *)prior_stage_fdt_address[0];
+               *fdtp = (void *)prior_stage_fdt_address[0];
+               return 0;
        }
 
-       if (fdt_magic(gd->fdt_blob) == FDT_MAGIC) {
-               *err = 0;
-               return (void *)gd->fdt_blob;
-       }
+       if (fdt_magic(*fdtp) == FDT_MAGIC)
+               return 0;
 
-       *err = -ENXIO;
-       return NULL;
+       return -ENXIO;
 }
 #endif
 
diff --git a/board/broadcom/bcmstb/bcmstb.c b/board/broadcom/bcmstb/bcmstb.c
index bc05aecc446..e655f610c84 100644
--- a/board/broadcom/bcmstb/bcmstb.c
+++ b/board/broadcom/bcmstb/bcmstb.c
@@ -130,9 +130,10 @@ int board_late_init(void)
        return 0;
 }
 
-void *board_fdt_blob_setup(int *err)
+int board_fdt_blob_setup(void **fdtp)
 {
-       *err = 0;
        /* Stored the DTB address there during our init */
-       return (void *)prior_stage_fdt_address;
+       *fdtp = (void *)prior_stage_fdt_address;
+
+       return 0;
 }
diff --git a/board/emulation/qemu-arm/qemu-arm.c 
b/board/emulation/qemu-arm/qemu-arm.c
index 6095cb02b23..8476796f1c3 100644
--- a/board/emulation/qemu-arm/qemu-arm.c
+++ b/board/emulation/qemu-arm/qemu-arm.c
@@ -149,11 +149,12 @@ int dram_init_banksize(void)
        return 0;
 }
 
-void *board_fdt_blob_setup(int *err)
+int board_fdt_blob_setup(void **fdtp)
 {
-       *err = 0;
        /* QEMU loads a generated DTB for us at the start of RAM. */
-       return (void *)CFG_SYS_SDRAM_BASE;
+       *fdtp = (void *)CFG_SYS_SDRAM_BASE;
+
+       return 0;
 }
 
 void enable_caches(void)
diff --git a/board/emulation/qemu-ppce500/qemu-ppce500.c 
b/board/emulation/qemu-ppce500/qemu-ppce500.c
index 58e5d5eb942..40d295dbf06 100644
--- a/board/emulation/qemu-ppce500/qemu-ppce500.c
+++ b/board/emulation/qemu-ppce500/qemu-ppce500.c
@@ -334,15 +334,11 @@ u32 cpu_mask(void)
        return (1 << cpu_numcores()) - 1;
 }
 
-/**
- * Return the virtual address of FDT that was passed by QEMU
- *
- * Return: virtual address of FDT received from QEMU in r3 register
- */
-void *board_fdt_blob_setup(int *err)
+int board_fdt_blob_setup(void **fdtp)
 {
-       *err = 0;
-       return get_fdt_virt();
+       *fdtp = get_fdt_virt();
+
+       return 0;
 }
 
 /* See CFG_SYS_NS16550_CLK in arch/powerpc/include/asm/config.h */
diff --git a/board/emulation/qemu-riscv/qemu-riscv.c 
b/board/emulation/qemu-riscv/qemu-riscv.c
index e5193e31e37..a90222ea6a4 100644
--- a/board/emulation/qemu-riscv/qemu-riscv.c
+++ b/board/emulation/qemu-riscv/qemu-riscv.c
@@ -64,9 +64,10 @@ int board_fit_config_name_match(const char *name)
 }
 #endif
 
-void *board_fdt_blob_setup(int *err)
+int board_fdt_blob_setup(void **fdtp)
 {
-       *err = 0;
        /* Stored the DTB address there during our init */
-       return (void *)(ulong)gd->arch.firmware_fdt_addr;
+       *fdtp = (void *)(ulong)gd->arch.firmware_fdt_addr;
+
+       return 0;
 }
diff --git a/board/highbank/highbank.c b/board/highbank/highbank.c
index f3df83ed6c9..0ec88447384 100644
--- a/board/highbank/highbank.c
+++ b/board/highbank/highbank.c
@@ -97,15 +97,16 @@ int ft_board_setup(void *fdt, struct bd_info *bd)
 }
 #endif
 
-void *board_fdt_blob_setup(int *err)
+int board_fdt_blob_setup(void **fdtp)
 {
-       *err = 0;
        /*
         * The ECME management processor loads the DTB from NOR flash
         * into DRAM (at 4KB), where it gets patched to contain the
         * detected memory size.
         */
-       return (void *)0x1000;
+       *fdtp = (void *)0x1000;
+
+       return 0;
 }
 
 static int is_highbank(void)
diff --git a/board/raspberrypi/rpi/rpi.c b/board/raspberrypi/rpi/rpi.c
index 9122f33d88d..c46fe4b2350 100644
--- a/board/raspberrypi/rpi/rpi.c
+++ b/board/raspberrypi/rpi/rpi.c
@@ -508,15 +508,14 @@ int board_init(void)
 /*
  * If the firmware passed a device tree use it for U-Boot.
  */
-void *board_fdt_blob_setup(int *err)
+int board_fdt_blob_setup(void **fdtp)
 {
-       *err = 0;
-       if (fdt_magic(fw_dtb_pointer) != FDT_MAGIC) {
-               *err = -ENXIO;
-               return NULL;
-       }
+       if (fdt_magic(fw_dtb_pointer) != FDT_MAGIC)
+               return -ENXIO;
 
-       return (void *)fw_dtb_pointer;
+       *fdtp = (void *)fw_dtb_pointer;
+
+       return 0;
 }
 
 int copy_property(void *dst, void *src, char *path, char *property)
diff --git a/board/sifive/unleashed/unleashed.c 
b/board/sifive/unleashed/unleashed.c
index 3c5dd50c369..c1c374610c3 100644
--- a/board/sifive/unleashed/unleashed.c
+++ b/board/sifive/unleashed/unleashed.c
@@ -114,15 +114,15 @@ int misc_init_r(void)
 
 #endif
 
-void *board_fdt_blob_setup(int *err)
+int board_fdt_blob_setup(void **fdtp)
 {
-       *err = 0;
-       if (IS_ENABLED(CONFIG_OF_SEPARATE) || IS_ENABLED(CONFIG_OF_BOARD)) {
-               if (gd->arch.firmware_fdt_addr)
-                       return (ulong *)(uintptr_t)gd->arch.firmware_fdt_addr;
+       if (gd->arch.firmware_fdt_addr) {
+               *fdtp = (ulong *)(uintptr_t)gd->arch.firmware_fdt_addr;
+
+               return 0;
        }
 
-       return (ulong *)_end;
+       return -EEXIST;
 }
 
 int board_init(void)
diff --git a/board/sifive/unmatched/unmatched.c 
b/board/sifive/unmatched/unmatched.c
index c8696270ba2..23e03e145ee 100644
--- a/board/sifive/unmatched/unmatched.c
+++ b/board/sifive/unmatched/unmatched.c
@@ -10,15 +10,14 @@
 #include <dm.h>
 #include <asm/sections.h>
 
-void *board_fdt_blob_setup(int *err)
+int board_fdt_blob_setup(void **fdtp)
 {
-       *err = 0;
-       if (IS_ENABLED(CONFIG_OF_SEPARATE) || IS_ENABLED(CONFIG_OF_BOARD)) {
-               if (gd->arch.firmware_fdt_addr)
-                       return (ulong *)(uintptr_t)gd->arch.firmware_fdt_addr;
+       if (gd->arch.firmware_fdt_addr) {
+               *fdtp = (ulong *)(uintptr_t)gd->arch.firmware_fdt_addr;
+               return 0;
        }
 
-       return (ulong *)_end;
+       return -EEXIST;
 }
 
 int board_init(void)
diff --git a/board/starfive/visionfive2/starfive_visionfive2.c 
b/board/starfive/visionfive2/starfive_visionfive2.c
index f6114602f88..3940d45b13f 100644
--- a/board/starfive/visionfive2/starfive_visionfive2.c
+++ b/board/starfive/visionfive2/starfive_visionfive2.c
@@ -115,15 +115,14 @@ int board_late_init(void)
        return 0;
 }
 
-void *board_fdt_blob_setup(int *err)
+int board_fdt_blob_setup(void **fdtp)
 {
-       *err = 0;
-       if (IS_ENABLED(CONFIG_OF_SEPARATE) || IS_ENABLED(CONFIG_OF_BOARD)) {
-               if (gd->arch.firmware_fdt_addr)
-                       return (ulong *)(uintptr_t)gd->arch.firmware_fdt_addr;
+       if (gd->arch.firmware_fdt_addr) {
+               *fdtp = (ulong *)(uintptr_t)gd->arch.firmware_fdt_addr;
+               return 0;
        }
 
-       return (ulong *)_end;
+       return -EEXIST;
 }
 
 int ft_board_setup(void *blob, struct bd_info *bd)
diff --git a/board/xen/xenguest_arm64/xenguest_arm64.c 
b/board/xen/xenguest_arm64/xenguest_arm64.c
index 4c3b9c9e278..216a022aa15 100644
--- a/board/xen/xenguest_arm64/xenguest_arm64.c
+++ b/board/xen/xenguest_arm64/xenguest_arm64.c
@@ -44,14 +44,14 @@ int board_init(void)
  * x0 is the physical address of the device tree blob (dtb) in system RAM.
  * This is stored in rom_pointer during low level init.
  */
-void *board_fdt_blob_setup(int *err)
+int board_fdt_blob_setup(void **fdtp)
 {
-       *err = 0;
-       if (fdt_magic(rom_pointer[0]) != FDT_MAGIC) {
-               *err = -ENXIO;
-               return NULL;
-       }
-       return (void *)rom_pointer[0];
+       if (fdt_magic(rom_pointer[0]) != FDT_MAGIC)
+               return -ENXIO;
+
+       *fdtp = (void *)rom_pointer[0];
+
+       return 0;
 }
 
 /*
diff --git a/board/xilinx/common/board.c b/board/xilinx/common/board.c
index 38dd80533fa..f9421b9a988 100644
--- a/board/xilinx/common/board.c
+++ b/board/xilinx/common/board.c
@@ -357,17 +357,17 @@ __maybe_unused int xilinx_read_eeprom(void)
 }
 
 #if defined(CONFIG_OF_BOARD)
-void *board_fdt_blob_setup(int *err)
+int board_fdt_blob_setup(void **fdtp)
 {
        void *fdt_blob;
 
-       *err = 0;
-
        if (IS_ENABLED(CONFIG_TARGET_XILINX_MBV)) {
                fdt_blob = (void *)CONFIG_XILINX_OF_BOARD_DTB_ADDR;
 
-               if (fdt_magic(fdt_blob) == FDT_MAGIC)
-                       return fdt_blob;
+               if (fdt_magic(fdt_blob) == FDT_MAGIC) {
+                       *fdtp = fdt_blob;
+                       return 0;
+               }
        }
 
        if (!IS_ENABLED(CONFIG_XPL_BUILD) &&
@@ -375,8 +375,10 @@ void *board_fdt_blob_setup(int *err)
            !IS_ENABLED(CONFIG_ZYNQMP_NO_DDR)) {
                fdt_blob = (void *)CONFIG_XILINX_OF_BOARD_DTB_ADDR;
 
-               if (fdt_magic(fdt_blob) == FDT_MAGIC)
-                       return fdt_blob;
+               if (fdt_magic(fdt_blob) == FDT_MAGIC) {
+                       *fdtp = fdt_blob;
+                       return 0;
+               }
 
                debug("DTB is not passed via %p\n", fdt_blob);
        }
@@ -395,13 +397,15 @@ void *board_fdt_blob_setup(int *err)
                fdt_blob = (ulong *)_end;
        }
 
-       if (fdt_magic(fdt_blob) == FDT_MAGIC)
-               return fdt_blob;
+       if (fdt_magic(fdt_blob) == FDT_MAGIC) {
+               *fdtp = fdt_blob;
+
+               return 0;
+       }
 
        debug("DTB is also not passed via %p\n", fdt_blob);
 
-       *err = -EINVAL;
-       return NULL;
+       return -EINVAL;
 }
 #endif
 
diff --git a/include/fdtdec.h b/include/fdtdec.h
index 555c9520379..58bbd8f392e 100644
--- a/include/fdtdec.h
+++ b/include/fdtdec.h
@@ -1191,11 +1191,12 @@ int fdtdec_resetup(int *rescan);
  *
  * The existing devicetree is available at gd->fdt_blob
  *
- * @err: 0 on success, -EEXIST if the devicetree is already correct, or other
- * internal error code if we fail to setup a DTB
- * @returns new devicetree blob pointer
+ * @fdtp: Existing devicetree blob pointer; update this and return 0 if a
+ * different devicetree should be used
+ * Return: 0 on success, -EEXIST if the existing FDT is OK, -ve error code if 
we
+ * fail to setup a DTB
  */
-void *board_fdt_blob_setup(int *err);
+int board_fdt_blob_setup(void **fdtp);
 
 /*
  * Decode the size of memory
diff --git a/lib/fdtdec.c b/lib/fdtdec.c
index 60e28173c03..c5d29d4385a 100644
--- a/lib/fdtdec.c
+++ b/lib/fdtdec.c
@@ -1706,11 +1706,17 @@ int fdtdec_setup(void)
 
        /* Allow the board to override the fdt address. */
        if (IS_ENABLED(CONFIG_OF_BOARD)) {
-               gd->fdt_blob = board_fdt_blob_setup(&ret);
-               if (!ret)
+               void *blob;
+
+               blob = (void *)gd->fdt_blob;
+               ret = board_fdt_blob_setup(&blob);
+               if (ret) {
+                       if (ret != -EEXIST)
+                               return ret;
+               } else {
                        gd->fdt_src = FDTSRC_BOARD;
-               else if (ret != -EEXIST)
-                       return ret;
+                       gd->fdt_blob = blob;
+               }
        }
 
        /* Allow the early environment to override the fdt address */
-- 
2.43.0

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