[PATCH v4 1/3] riscv: Avoid the reserved memory fixup if src and dst point to the same place

[Bin Meng]

From: Bin Meng <bin.meng at windriver.com>

The copy of reserved memory node from source dtb to destination dtb
can be avoided if they point to the same place. This is useful when
OF_PRIOR_STAGE is used.

Signed-off-by: Bin Meng <bin.meng at windriver.com>
Reviewed-by: Rick Chen <rick at andestech.com>
Reviewed-by: Atish Patra <atish.patra at wdc.com>
---

(no changes since v1)

 arch/riscv/lib/fdt_fixup.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/arch/riscv/lib/fdt_fixup.c b/arch/riscv/lib/fdt_fixup.c
index 6db48ad..5f523f0 100644
--- a/arch/riscv/lib/fdt_fixup.c
+++ b/arch/riscv/lib/fdt_fixup.c
@@ -82,10 +82,9 @@ int riscv_fdt_copy_resv_mem_node(const void *src, void *dst)
  * @fdt: Pointer to the device tree in which reserved memory node needs to be
  *	 added.
  *
- * In RISC-V, any board compiled with OF_SEPARATE needs to copy the reserved
- * memory node from the device tree provided by the firmware to the device tree
- * used by U-Boot. This is a common function that individual board fixup
- * functions can invoke.
+ * In RISC-V, any board needs to copy the reserved memory node from the device
+ * tree provided by the firmware to the device tree used by U-Boot. This is a
+ * common function that individual board fixup functions can invoke.
  *
  * Return: 0 on success or error otherwise.
  */
@@ -95,6 +94,11 @@ int riscv_board_reserved_mem_fixup(void *fdt)
 	void *src_fdt_addr;
 
 	src_fdt_addr = map_sysmem(gd->arch.firmware_fdt_addr, 0);
+
+	/* avoid the copy if we are using the same device tree */
+	if (src_fdt_addr == fdt)
+		return 0;
+
 	err = riscv_fdt_copy_resv_mem_node(src_fdt_addr, fdt);
 	if (err < 0)
 		return err;
-- 
2.7.4