riscv: Provide a mechanism to fix DT for reserved memory

In RISC-V, M-mode software can reserve physical memory regions
by setting appropriate physical memory protection (PMP) csr. As the
PMP csr are accessible only in M-mode, S-mode U-Boot can not read
this configuration directly. However, M-mode software can pass this
information via reserved-memory node in device tree so that S-mode
software can access this information.

This patch provides a framework to copy to the reserved-memory node
from one DT to another. This will be used to update the DT used by
U-Boot and the DT passed to the next stage OS.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/riscv/include/asm/u-boot-riscv.h b/arch/riscv/include/asm/u-boot-riscv.h
index 49febd5..543a168 100644
--- a/arch/riscv/include/asm/u-boot-riscv.h
+++ b/arch/riscv/include/asm/u-boot-riscv.h
@@ -17,5 +17,7 @@
 /* board/.../... */
 int board_init(void);
 void board_quiesce_devices(void);
+int riscv_board_reserved_mem_fixup(void *fdt);
+int riscv_fdt_copy_resv_mem_node(const void *src_fdt, void *dest_fdt);
 
 #endif	/* _U_BOOT_RISCV_H_ */