[U-Boot] [PATCH v10 3/8] nds32/core N1213: NDS32 N12 core family N1213

[Macpaul Lin <macpaul@andestech.com>]

Add N1213 cpu core (N12 Core family) support for NDS32 arch.
This patch includes start.S for the initialize procedure of N1213.

NDS32 Core N1213 has the following hardware features.

 Core:
  - 16-/32-bit mixable instruction format
  - 32 general-purpose 32-bit registers
  - 8-stage pipeline
  - Dynamic branch prediction
  - 32/64/128/256 BTB
  - Return address stack (RAS)
  - Vector interrupts for internal/external
  - 3 HW-level nested interruptions
  - User and super-user mode support
  - Memory-mapped I/O
  - Address space up to 4GB

 Memory Management Unit:
  - TLB
  - Optional hardware page table walker
  - Two groups of page size support

 Memory Subsystem:
  - I & D cache
  - I & D local memory (LM)

 Bus Interface:
  - Synchronous/Asynchronous AHB bus: 0, 1 or 2 ports

Start procedure:
 start.S will start up the N1213 CPU core at first,
 then jump to SoC dependent "lowlevel_init.S" and
 "watchdog.S" to configure peripheral devices.

Signed-off-by: Macpaul Lin <macpaul@andestech.com>
---
Changes v1 to v6:
  - Style clean up and reorganize code
Changes v7-v9:
  - No Change.
Changes v10:
  - start.S of N1213 CPU has been rewrote for relocation support.
  - u-boot.lds:
   - Add got and *(.got.plt) section for support GCC 4 toolchain
   - Modified for relocation implementation.

 arch/nds32/cpu/n1213/Makefile   |   50 ++++
 arch/nds32/cpu/n1213/start.S    |  523 +++++++++++++++++++++++++++++++++++++++
 arch/nds32/cpu/n1213/u-boot.lds |   72 ++++++
 3 files changed, 645 insertions(+), 0 deletions(-)
 create mode 100644 arch/nds32/cpu/n1213/Makefile
 create mode 100644 arch/nds32/cpu/n1213/start.S
 create mode 100644 arch/nds32/cpu/n1213/u-boot.lds

diff --git a/arch/nds32/cpu/n1213/Makefile b/arch/nds32/cpu/n1213/Makefile
new file mode 100644
index 0000000..111d14f
--- /dev/null
+++ b/arch/nds32/cpu/n1213/Makefile
@@ -0,0 +1,50 @@
+#
+# (C) Copyright 2000-2006
+# Wolfgang Denk, DENX Software Engineering, wd at denx.de.
+#
+# Copyright (C) 2011 Andes Technology Corporation
+# Shawn Lin, Andes Technology Corporation <nobuhiro@andestech.com>
+# Macpaul Lin, Andes Technology Corporation <macpaul@andestech.com>
+#
+# See file CREDITS for list of people who contributed to this
+# project.
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License as
+# published by the Free Software Foundation; either version 2 of
+# the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+# MA 02111-1307 USA
+#
+
+include $(TOPDIR)/config.mk
+
+LIB	= $(obj)lib$(CPU).o
+
+START	= start.o
+
+SRCS	:= $(START:.o=.S) $(SOBJS:.o=.S) $(COBJS:.o=.c)
+OBJS	:= $(addprefix $(obj),$(COBJS) $(SOBJS))
+START	:= $(addprefix $(obj),$(START))
+
+all:	$(obj).depend $(START) $(LIB)
+
+$(LIB):	$(OBJS)
+	$(AR) $(ARFLAGS) $@ $(OBJS)
+
+#########################################################################
+
+# defines $(obj).depend target
+include $(SRCTREE)/rules.mk
+
+sinclude $(obj).depend
+
+#########################################################################
diff --git a/arch/nds32/cpu/n1213/start.S b/arch/nds32/cpu/n1213/start.S
new file mode 100644
index 0000000..602067e
--- /dev/null
+++ b/arch/nds32/cpu/n1213/start.S
@@ -0,0 +1,523 @@
+/*
+ *	Andesboot - Startup Code for Whitiger core
+ *
+ *	Copyright (C) 2006	Andes Technology Corporation
+ *	Copyright (C) 2006	Shawn Lin <nobuhiro@andestech.com>
+ *	Copyright (C) 2011	Macpaul <macpaul@andestech.com>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <asm-offsets.h>
+#include <config.h>
+#include <common.h>
+#include <asm/macro.h>
+#include <version.h>
+
+/*
+ * Jump vector table for EVIC mode
+ */
+#define ENA_DCAC		2UL
+#define DIS_DCAC		~ENA_DCAC
+#define ICAC_MEM_KBF_ISET	(0x07)	 	! I Cache sets per way
+#define ICAC_MEM_KBF_IWAY	(0x07<<3)	! I cache ways
+#define ICAC_MEM_KBF_ISZ	(0x07<<6)	! I cache line size
+#define DCAC_MEM_KBF_DSET	(0x07)		! D Cache sets per way
+#define DCAC_MEM_KBF_DWAY	(0x07<<3)	! D cache ways
+#define DCAC_MEM_KBF_DSZ	(0x07<<6)	! D cache line size
+
+#define PSW			$ir0
+#define EIT_INTR_PSW		$ir1		! interruption $PSW
+#define EIT_PREV_IPSW		$ir2		! previous $IPSW
+#define EIT_IVB			$ir3		! intr vector base address
+#define EIT_EVA			$ir4		! MMU related Exception Virtual Address register
+#define EIT_PREV_EVA		$ir5		! previous $eva
+#define EIT_ITYPE		$ir6		! interruption type
+#define EIT_PREV_ITYPE		$ir7		! prev intr type
+#define EIT_MACH_ERR		$ir8		! machine error log
+#define EIT_INTR_PC		$ir9		! Interruption PC
+#define EIT_PREV_IPC		$ir10		! previous $IPC
+#define EIT_OVL_INTR_PC		$ir11		! overflow interruption PC
+#define EIT_PREV_P0		$ir12		! prev $P0
+#define EIT_PREV_P1		$ir13		! prev $p1
+#define CR_ICAC_MEM		$cr1		! I-cache/memory config reg
+#define CR_DCAC_MEM		$cr2		! D-cache/memory config reg
+#define MR_CAC_CTL		$mr8
+
+.globl _start
+
+_start:	b	reset
+	b	tlb_fill
+	b	tlb_not_present
+	b	tlb_misc
+	b	tlb_vlpt_miss
+	b	cache_parity_error
+	b	debug
+	b	general_exception
+	b	internal_interrupt		! H0I
+	b	internal_interrupt		! H1I
+	b	internal_interrupt		! H2I
+	b	internal_interrupt		! H3I
+	b	internal_interrupt		! H4I
+	b	internal_interrupt		! H5I
+
+	.balign 16
+
+/*
+ * Andesboot Startup Code (reset vector)
+ *
+ *	1.	bootstrap
+ *		1.1 reset - start of Andesboot
+ *		1.2 to superuser mode - as is when reset
+ *		1.4 Do lowlevel_init
+ *			- (this will jump out to lowlevel_init.S in SoC)
+ *			- (lowlevel_init)
+ *		1.3 Turn off watchdog timer
+ *			- (this will jump out to watchdog.S in SoC)
+ *			- (turnoff_watchdog)
+ *	2.	Do critical init when reboot (not from mem)
+ *	3.	Relocate andesboot to ram
+ *	4.	Setup stack
+ *	5.	Jump to second stage (start_andesboot)
+ */
+
+/* Note: TEXT_BASE is defined by the (board-dependent) linker script */
+.globl _TEXT_BASE
+_TEXT_BASE:
+	.word	CONFIG_SYS_TEXT_BASE
+
+/*
+ * These are defined in the board-specific linker script.
+ * Subtracting _start from them lets the linker put their
+ * relative position in the executable instead of leaving
+ * them null.
+ */
+.globl _bss_start_ofs
+_bss_start_ofs:
+	.word __bss_start - _start
+
+.globl _bss_end_ofs
+_bss_end_ofs:
+	.word __bss_end__ - _start
+
+.globl _end_ofs
+_end_ofs:
+	.word _end - _start
+
+#ifdef CONFIG_USE_IRQ
+/* IRQ stack memory (calculated at run-time) */
+.globl IRQ_STACK_START
+IRQ_STACK_START:
+	.word 0x0badc0de
+
+/* IRQ stack memory (calculated at run-time) */
+.globl FIQ_STACK_START
+FIQ_STACK_START:
+	.word 0x0badc0de
+#endif
+
+/* IRQ stack memory (calculated at run-time) + 8 bytes */
+.globl IRQ_STACK_START_IN
+IRQ_STACK_START_IN:
+	.word 0x0badc0de
+
+/*
+ * The bootstrap code of nds32 core
+ */
+
+reset:
+
+load_lli:
+#ifndef CONFIG_SKIP_LOWLEVEL_INIT
+	jal	load_lowlevel_init
+	jral	$p0
+#endif
+
+/*
+ * Set the N1213 (Whitiger) core to superuser mode
+ * According to spec, it is already when reset
+ */
+turnoff_wtdog:
+#ifndef CONFIG_SKIP_TRUNOFF_WATCHDOG
+	jal	load_turnoff_watchdog
+	jral	$p0
+#endif
+
+/*
+ * Do CPU critical regs init only at reboot,
+ * not when booting from ram
+ */
+#ifdef CONFIG_INIT_CRITICAL
+	bal	cpu_init_crit		! Do CPU critical regs init
+#endif
+
+/*
+ * Set stackpointer in internal RAM to call board_init_f
+ * $sp must be 8-byte alignment for ABI compliance.
+ */
+call_board_init_f:
+	li	$sp, CONFIG_SYS_INIT_SP_ADDR
+	li	$r0, 0x00000000
+
+#ifdef __PIC__
+#ifdef __NDS32_N1213_43U1H__
+/* __NDS32_N1213_43U1H__ implies NDS32 V0 ISA */
+	la	$r15, board_init_f	! store function address into $r15
+#endif
+#endif
+	j	board_init_f		! jump to board_init_f() in lib/board.c
+
+/*
+ * void relocate_code (addr_sp, gd, addr_moni)
+ *
+ * This "function" does not return, instead it continues in RAM
+ * after relocating the monitor code.
+ *
+ */
+.globl	relocate_code
+relocate_code:
+	move	$r4, $r0		/* save addr_sp */
+	move	$r5, $r1		/* save addr of gd */
+	move	$r6, $r2		/* save addr of destination */
+
+/* Set up the stack */
+stack_setup:
+	move	$sp, $r4
+
+	la	$r0, _start
+
+	beq	$r0, $r6, clear_bss	/* skip relocation */
+
+	move	$r1, $r6		/* r1 <- scratch for copy_loop */
+	l.w	$r3, _bss_start_ofs
+	add	$r2, $r0, $r3		/* r2 <- source end address */
+
+copy_loop:
+	lwi.p	$r7, [$r0], #4
+	swi.p	$r7, [$r1], #4
+	blt	$r0, $r2, copy_loop
+
+/*
+ * fix relocations related issues
+ */
+fix_relocations:
+	l.w	$r0, _TEXT_BASE		/* r0 <- Text base */
+	sub	$r9, $r6, $r0		/* r9 <- relocation offset */
+
+fix_got:
+/*
+ * Now we want to update GOT.
+ *
+ * GOT[0] is reserved. GOT[1] is also reserved for the dynamic object
+ * generated by GNU ld. Skip these reserved entries from relocation.
+ */
+	l.w	$r2, _rel_got_start_ofs	/* r2 <- rel got start ofs */
+	add	$r2, $r2, $r0		/* r2 <- rel got start in FLASH */
+	add	$r2, $r2, $r9		/* r2 <- rel got start in RAM */
+	l.w	$r3, _rel_got_end_ofs	/* r3 <- rel got end ofs */
+	add	$r3, $r3, $r0		/* r3 <- rel got end in FLASH */
+	add	$r3, $r3, $r9		/* r3 <- rel got end in RAM */
+	addi	$r2, $r2, #8		/* skipping first two entries */
+fix_got_loop:
+	lwi	$r0, [$r2]		/* r0 <- location in FLASH to fix up */
+	add	$r0, $r0, $r9		/* r0 <- location fix up to RAM */
+	swi.p	$r0, [$r2], #4		/* r0 <- store fix into .got in RAM */
+	blt	$r2, $r3, fix_got_loop
+
+clear_bss:
+	l.w	$r0, _bss_start_ofs
+	l.w	$r1, _bss_end_ofs
+	move	$r4, $r6		/* reloc addr */
+	add	$r0, $r0, $r4
+	add	$r1, $r1, $r4
+	li	$r2, 0x00000000		/* clear */
+
+clbss_l:
+	sw	$r2, [$r0]		/* clear loop... */
+	addi	$r0, $r0, #4
+	bne	$r0, $r1, clbss_l
+
+/*
+ * We are done. Do not return, instead branch to second part of board
+ * initialization, now running from RAM.
+ */
+call_board_init_r:
+	l.w	$r0, _board_init_r_ofs
+	la	$r1, _start
+	add	$lp, $r0, $r1		/* offset of board_init_f() */
+	add	$lp, $lp, $r9		/* real address of board_init_f() */
+	/* setup parameters for board_init_r */
+	move	$r0, $r5		/* gd_t */
+	move	$r1, $r6		/* dest_addr */
+
+#ifdef __PIC__
+#ifdef __NDS32_N1213_43U1H__		/* NDS32 V0 ISA	*/
+	move	$r15, $lp		/* store function address into $r15 */
+#endif
+#endif
+
+	/* jump to it ... */
+	jr	$lp			/* jump to board_init_r() */
+
+_board_init_r_ofs:
+	.word board_init_r - _start
+_rel_got_start_ofs:
+	.word __got_start - _start
+_rel_got_end_ofs:
+	.word __got_end - _start
+
+/*
+ * Initialize CPU critical registers
+ *
+ *	1.	Setup control registers
+ *		1.1 Mask all IRQs
+ *		1.2 Flush cache and TLB
+ *		1.3 Disable MMU and cache
+ *	2.	Setup memory timing
+ */
+
+cpu_init_crit:
+
+	move	$r0, $lp		/* push	ra */
+
+	/* Disable Interrupts by clear GIE in $PSW reg */
+	setgie.d
+
+	/* Flush caches and TLB */
+	/* Invalidate caches */
+	bal	invalidate_icac
+	bal	invalidate_dcac
+
+	/* Flush TLB */
+	mfsr	$p0, $MMU_CFG
+	andi	$p0, $p0, 0x3			! MMPS
+	li	$p1, 0x2			! TLB MMU
+	bne	$p0, $p1, 1f
+	tlbop	flushall			! Flush TLB
+
+1:
+	! Disable MMU, Dcache
+	! Whitiger is MMU disabled when reset
+	! Disable the D$
+	mfsr	$p0, MR_CAC_CTL			! Get the $CACHE_CTL reg
+	li	$p1, DIS_DCAC
+	and	$p0, $p0, $p1			! Set DC_EN bit
+	mtsr	$p0, MR_CAC_CTL			! write back the $CACHE_CTL reg
+	isb
+
+	move	$lp, $r0
+2:
+	ret
+
+#ifndef CONFIG_SKIP_LOWLEVEL_INIT
+load_lowlevel_init:
+	la  $r6, lowlevel_init
+	la  $r7, load_lli + 4
+	sub $p0, $r6, $r7
+	add $p0, $p0, $lp
+ret
+#endif
+
+#ifndef CONFIG_SKIP_TRUNOFF_WATCHDOG
+load_turnoff_watchdog:
+	la  $r6, turnoff_watchdog
+	la  $r7, turnoff_wtdog + 4
+	sub $p0, $r6, $r7
+	add $p0, $p0, $lp
+ret
+#endif
+
+/*
+ * Invalidate I$
+ */
+invalidate_icac:
+	mfsr	$t0, CR_ICAC_MEM		! read $cr1(I CAC/MEM cfg. reg.) configuration
+	andi	$p0, $t0, ICAC_MEM_KBF_ISZ 	! Get the ISZ field
+	beqz	$p0, end_flush_icache		! if $p0=0, then no I CAC existed
+	srli	$p0, $p0, 6			! get $p0 the index of I$ block
+	addi	$t1, $p0, 2			! $t1= bit width of I cache line size(ISZ)
+	li	$t4, 1
+	sll	$t5, $t4, $t1			! get $t5 cache line size
+	andi	$p1, $t0, ICAC_MEM_KBF_ISET	! get the ISET field
+	addi	$t2, $p1, 6			! $t2= bit width of ISET
+	andi	$p1, $t0, ICAC_MEM_KBF_IWAY	! get bitfield of Iway
+	srli	$p1, $p1, 3
+	addi	$p1, $p1, 1			! then $p1 is I way number
+	add	$t3, $t2, $t1			! SHIFT
+	sll	$p1, $p1, $t3			! GET the total cache size
+ICAC_LOOP:
+	sub	$p1, $p1, $t5
+	cctl	$p1, L1I_IX_INVAL
+	bnez	$p1, ICAC_LOOP
+end_flush_icache:
+	ret
+
+/*
+ * Invalidate D$
+ */
+invalidate_dcac:
+	mfsr	$t0, CR_DCAC_MEM		! read $cr2(D CAC/MEM cfg. reg.) configuration
+	andi	$p0, $t0, DCAC_MEM_KBF_DSZ	! Get the DSZ field
+	beqz	$p0, end_flush_dcache		! if $p0=0, then no D CAC existed
+	srli	$p0, $p0, 6			! get $p0 the index of D$ block
+	addi	$t1, $p0, 2			! $t1= bit width of D cache line size(DSZ)
+	li	$t4, 1
+	sll	$t5, $t4, $t1			! get $t5 cache line size
+	andi	$p1, $t0, DCAC_MEM_KBF_DSET	! get the DSET field
+	addi	$t2, $p1, 6			! $t2= bit width of DSET
+	andi	$p1, $t0, DCAC_MEM_KBF_DWAY	! get bitfield of D way
+	srli	$p1, $p1, 3
+	addi	$p1, $p1, 1			! then $p1 is D way number
+	add	$t3, $t2, $t1			! SHIFT
+	sll	$p1, $p1, $t3			! GET the total cache size
+DCAC_LOOP:
+	sub	$p1, $p1, $t5
+	cctl	$p1, L1D_IX_INVAL
+	bnez	$p1, DCAC_LOOP
+end_flush_dcache:
+	ret
+
+/*
+ * Interrupt handling
+ */
+
+/*
+ * exception handlers
+ */
+	.align	5
+
+.macro	SAVE_ALL
+	! FIXME: Other way to get PC?
+	! FIXME: Update according to the newest spec!!
+1:
+	la	 $r28, 1
+	push $r28
+	mfsr $r28, PSW			! $PSW
+	push $r28
+	mfsr $r28, EIT_EVA		! $ir1 $EVA
+	push $r28
+	mfsr $r28, EIT_ITYPE		! $ir2 $ITYPE
+	push $r28
+	mfsr $r28, EIT_MACH_ERR		! $ir3 Mach Error
+	push $r28
+	mfsr $r28, EIT_INTR_PSW		! $ir5 $IPSW
+	push $r28
+	mfsr $r28, EIT_PREV_IPSW	! $ir6 prev $IPSW
+	push $r28
+	mfsr $r28, EIT_PREV_EVA		! $ir7 prev $EVA
+	push $r28
+	mfsr $r28, EIT_PREV_ITYPE	! $ir8 prev $ITYPE
+	push $r28
+	mfsr $r28, EIT_INTR_PC		! $ir9 Interruption PC
+	push $r28
+	mfsr $r28, EIT_PREV_IPC		! $ir10 prev INTR_PC
+	push $r28
+	mfsr $r28, EIT_OVL_INTR_PC	! $ir11 Overflowed INTR_PC
+	push $r28
+	mfusr $r28, $d1.lo
+	push $r28
+	mfusr $r28, $d1.hi
+	push $r28
+	mfusr $r28, $d0.lo
+	push $r28
+	mfusr $r28, $d0.hi
+	push $r28
+	pushm $r0, $r30		! store $sp-$r31, ra-$r30, $gp-$r29, $r28-$fp
+	addi	$sp, $sp, -4	! make room for implicit pt_regs parameters
+.endm
+
+	.align	5
+tlb_fill:
+	SAVE_ALL
+	move	$r0, $sp			! To get the kernel stack
+	li	$r1, 1				! Determine interruption type
+	bal 	do_interruption
+
+	.align	5
+tlb_not_present:
+	SAVE_ALL
+	move	$r0, $sp			! To get the kernel stack
+	li	$r1, 2				! Determine interruption type
+	bal 	do_interruption
+
+	.align	5
+tlb_misc:
+	SAVE_ALL
+	move	$r0, $sp			! To get the kernel stack
+	li	$r1, 3				! Determine interruption type
+	bal 	do_interruption
+
+	.align	5
+tlb_vlpt_miss:
+	SAVE_ALL
+	move	$r0, $sp			! To get the kernel stack
+	li	$r1, 4				! Determine interruption type
+	bal	do_interruption
+
+	.align	5
+cache_parity_error:
+	SAVE_ALL
+	move	$r0, $sp			! To get the kernel stack
+	li	$r1, 5				! Determine interruption type
+	bal	do_interruption
+
+	.align	5
+debug:
+	SAVE_ALL
+	move	$r0, $sp			! To get the kernel stack
+	li	$r1, 6				! Determine interruption type
+	bal	do_interruption
+
+	.align	5
+general_exception:
+	SAVE_ALL
+	move	$r0, $sp			! To get the kernel stack
+	li	$r1, 7				! Determine interruption type
+	bal	do_interruption
+
+	.align	5
+internal_interrupt:
+	SAVE_ALL
+	move	$r0, $sp			! To get the kernel stack
+	li	$r1, 8				! Determine interruption type
+	bal	do_interruption
+
+	.align	5
+
+/*
+ * void reset_cpu(ulong addr);
+ * $r0: input address to jump to
+ */
+.globl reset_cpu
+reset_cpu:
+/* No need to disable MMU because we never enable it */
+
+	bal	invalidate_icac
+	bal	invalidate_dcac
+	mfsr	$p0, $MMU_CFG
+	andi	$p0, $p0, 0x3			! MMPS
+	li	$p1, 0x2			! TLB MMU
+	bne	$p0, $p1, 1f
+	tlbop	flushall			! Flush TLB
+1:
+	mfsr	$p0, MR_CAC_CTL			! Get the $CACHE_CTL reg
+	li	$p1, DIS_DCAC
+	and	$p0, $p0, $p1			! Clear the DC_EN bit
+	mtsr	$p0, MR_CAC_CTL			! Write back the $CACHE_CTL reg
+	br	$r0				! Jump to the input address
diff --git a/arch/nds32/cpu/n1213/u-boot.lds b/arch/nds32/cpu/n1213/u-boot.lds
new file mode 100644
index 0000000..194f45a
--- /dev/null
+++ b/arch/nds32/cpu/n1213/u-boot.lds
@@ -0,0 +1,72 @@
+/*
+ * (C) Copyright 2000
+ * Wolfgang Denk, DENX Software Engineering, wd at denx.de.
+ *
+ * Copyright (C) 2011 Andes Technology Corporation
+ * Shawn Lin, Andes Technology Corporation <nobuhiro@andestech.com>
+ * Macpaul Lin, Andes Technology Corporation <macpaul@andestech.com>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+OUTPUT_FORMAT("elf32-nds32", "elf32-nds32", "elf32-nds32")
+OUTPUT_ARCH(nds32)
+ENTRY(_start)
+SECTIONS
+{
+	. = 0x00000000;
+
+	. = ALIGN(4);
+	.text :
+	{
+		arch/nds32/cpu/n1213/start.o	(.text)
+		*(.text)
+	}
+
+	. = ALIGN(4);
+	.rodata : { *(SORT_BY_ALIGNMENT(SORT_BY_NAME(.rodata*))) }
+
+	. = ALIGN(4);
+	.data : { *(.data) }
+
+	. = ALIGN(4);
+
+	.got : {
+		__got_start = .;
+		 *(.got.plt) *(.got)
+		__got_end = .;
+	}
+
+	. = .;
+	__u_boot_cmd_start = .;
+	.u_boot_cmd : { *(.u_boot_cmd) }
+	__u_boot_cmd_end = .;
+
+	. = ALIGN(4);
+
+	_end = .;
+
+	.bss : {
+		__bss_start = .;
+		*(.bss)
+		 . = ALIGN(4);
+		__bss_end__ = .;
+	}
+
+}
-- 
1.7.3.5