参考：http://blog.csdn.net/bekars/article/details/710888
我的s3c2410硬件：
Nand Flash：K9s1208V?
Nor Flash：Amd29LV160BB（最大2M，当然要自己扩充，默认是512k）
SDRAM ：HY（64M,现代）
1)在board/sbc2410x加入NAND Flash读函数，建立nand_read.c，加入如下内容(copy from vivi)：
#include <config.h>
#define __REGb(x)?(*(volatile unsigned char *)(x))
#define __REGi(x)?(*(volatile unsigned int *)(x))
#define NF_BASE??0x4e000000
#define NFCONF??__REGi(NF_BASE + 0x0)
#define NFCMD??__REGb(NF_BASE + 0x4)
#define NFADDR??__REGb(NF_BASE + 0x8)
#define NFDATA??__REGb(NF_BASE + 0xc)
#define NFSTAT??__REGb(NF_BASE + 0x10)
#define BUSY 1
inline void wait_idle(void) {
??? int i;
??? while(!(NFSTAT & BUSY))
????? for(i=0; i<10; i++);
}
#define NAND_SECTOR_SIZE?512
#define NAND_BLOCK_MASK??(NAND_SECTOR_SIZE - 1)
/* low level nand read function */
int
nand_read_ll(unsigned char *buf,unsigned long start_addr,int size)
{
??? int i,j;
??? if ((start_addr & NAND_BLOCK_MASK) || (size & NAND_BLOCK_MASK)) {
??????? return -1;?/* invalid alignment */
??? }
??? /* chip Enable */
??? NFCONF &= ~0x800;
??? for(i=0; i<10; i++);
??? for(i=start_addr; i < (start_addr + size);) {
????? /* READ0 */
????? NFCMD = 0;
????? /* Write Address */
????? NFADDR = i & 0xff;
????? NFADDR = (i >> 9) & 0xff;
????? NFADDR = (i >> 17) & 0xff;
????? NFADDR = (i >> 25) & 0xff;
????? wait_idle();
????? for(j=0; j < NAND_SECTOR_SIZE; j++,i++) {
?*buf = (NFDATA & 0xff);
?buf++;
????? }
??? }
??? /* chip Disable */
??? NFCONF |= 0x800;?/* chip disable */
??? return 0;
}
2）修改board/sbc2410x/Makefile为
OBJS?:= bks2410.o flash.o nand_read.o
3）修改cpu/arm920t/start.S文件
在ldr?pc,_start_armboot之前加入：
#ifdef CONFIG_S3C2410_NAND_BOOT
? bl??? copy_myself
?
? @ jump to ram
? ldr?? r1,=on_the_ram
? add? pc,r1,#0
? nop
? nop
? 1:??? b???? 1b????????? @ infinite loop
?
on_the_ram:
#endif
在_start_armboot:?.word start_armboot之后加入：
#ifdef CONFIG_S3C2410_NAND_BOOT
copy_myself:
? mov r10,lr
@ reset NAND
? mov r1,#NAND_CTL_BASE
? ldr?? r2,=0xf830?????????? @ initial value
? str?? r2,[r1,#oNFCONF]
? ldr?? r2,#oNFCONF]
? bic? r2,r2,#0x800????????????? @ enable chip
? str?? r2,#oNFCONF]
? mov r2,#0xff???????? @ RESET command
? strb r2,#oNFCMD]
? mov r3,#0?????????????????? @ wait
1:add? r3,r3,#0x1
? cmp r3,#0xa
? blt?? 1b
2:ldr?? r2,#oNFSTAT]????? @ wait ready
? tst??? r2,#0x1
? beq? 2b
? ldr?? r2,#oNFCONF]
? orr? r2,#0x800????????????? @ disable chip
? str?? r2,#oNFCONF]
@ get read to call C functions (for nand_read())
? ldr?? sp,DW_STACK_START?????? @ setup stack pointer
? mov fp,#0??????????????????? @ no previous frame,so fp=0
@ copy vivi to RAM
? ldr?? r0,=UBOOT_RAM_BASE
? mov???? r1,#0x0
? mov r2,#0x20000
? bl??? nand_read_ll
? tst??? r0,#0x0
? beq? ok_nand_read
#ifdef CONFIG_DEBUG_LL
? bad_nand_read:
? ldr?? r0,STR_FAIL
? ldr?? r1,SerBase
? bl??? PrintWord
1:b???? 1b????????? @ infinite loop
? #endif
ok_nand_read:
#ifdef CONFIG_DEBUG_LL
? ldr?? r0,STR_OK
? ldr?? r1,SerBase
? bl??? PrintWord
#endif
@ verify
? mov r0,#0
? ldr?? r1,=UBOOT_RAM_BASE
? mov r2,#0x400???? @ 4 bytes * 1024 = 4K-bytes
go_next:
? ldr?? r3,[r0],#4
? ldr?? r4,[r1],#4
? teq?? r3,r4
? bne? notmatch
? subs r2,#4
? beq? done_nand_read
? bne? go_next
notmatch:
#ifdef CONFIG_DEBUG_LL
? sub? r0,r0,#4
? ldr?? r1,SerBase
? bl??? PrintHexWord
? ldr?? r0,SerBase
? bl??? PrintWord
#endif
1:b???? 1b
done_nand_read:
#ifdef CONFIG_DEBUG_LL
? ldr?? r0,SerBase
? bl??? PrintWord
#endif
? mov pc,r10
@ clear memory
@ r0: start address
@ r1: length
? mem_clear:
? mov r2,#0
? mov r3,r2
? mov r4,r2
? mov r5,r2
? mov r6,r2
? mov r7,r2
? mov r8,r2
? mov r9,r2
clear_loop:
? stmia????? r0!,{r2-r9}
? subs r1,#(8 * 4)
? bne? clear_loop
? mov pc,lr
#endif @ CONFIG_S3C2410_NAND_BOOT
在文件的最后加入：
? ?.align???? 2
DW_STACK_START:
?.word????? STACK_BASE+STACK_SIZE-4
4）修改include/configs/sbc2410x.h文件，添加如下内容：
/*
?* Nandflash Boot
?*/
由于NandFlash启动已经实现了代码定位，所以
#define CONFIG_SKIP_RELOCATE_UBOOT 1这样Start.S中的下面就不会执行：
?????????????????????? #ifndef CONFIG_SKIP_RELOCATE_UBOOT
????????????????????????????? relocate:?? ??? ??? ??? ?/* relocate U-Boot to RAM?? ???? */
? ? ? ? ? ? ? ? ? ? ? ? ? ??? adr?? ?r0,_start?? ??? ?/* r0 <- current position of code?? */
?? ? ? ? ? ? ? ? ? ? ? ? ? ?? ldr?? ?r1,_TEXT_BASE?? ??? ?/* test if we run from flash or RAM */
?? ? ? ? ? ? ? ? ? ? ? ? ? ?? cmp???? r0,r1????????????????? /* don't reloc during debug???????? */
? ? ? ? ? ? ? ? ? ? ? ? ? ? ? beq???? stack_setup
? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ldr?? ?r2,_armboot_start
? ? ? ? ? ? ? ? ? ? ? ? ? ?? ldr?? ?r3,_bss_start
? ? ? ? ? ? ? ? ? ? ? ? ? ?? sub?? ?r2,r2?? ??? ?/* r2 <- size of armboot??????????? */
? ? ? ? ? ? ? ? ? ? ? ? ? ?? add?? ?r2,r2?? ??? ?/* r2 <- source end address???????? */
?????????????????????????? copy_loop:
? ? ? ? ? ? ? ? ? ? ? ? ?? ldmia?? ?r0!,{r3-r10}?? ??? ?/* copy from source address [r0]??? */
? ? ? ? ? ? ? ? ? ? ? ? ? stmia?? ?r1!,{r3-r10}?? ??? ?/* copy to?? target address [r1]??? */
? ? ? ? ? ? ? ? ? ? ? ? ? cmp?? ?r0,r2?? ??? ??? ?/* until source end addreee [r2]??? */
? ? ? ? ? ? ? ? ? ? ? ? ? ble?? ?copy_loop
????????????????????????? #endif?? ?/* CONFIG_SKIP_RELOCATE_UBOOT */
#define CONFIG_S3C2410_NAND_BOOT 1
#define STACK_BASE ?? 0x33f00000
#define STACK_SIZE ?? 0x8000
#define UBOOT_RAM_BASE ?? 0x33f80000
/* NAND Flash Controller */
#define NAND_CTL_BASE??????????? 0x4E000000
#define bINT_CTL(Nb)??????? __REG(INT_CTL_BASE + (Nb))
/* Offset */
#define oNFCONF?????????????? 0x00
#define oNFCMD??????????????? 0x04
#define oNFADDR?????????????? 0x08
#define oNFDATA?????????????? 0x0c
#define oNFSTAT?????????????? 0x10
#define oNFECC??????????????? 0x14
5）重新编译u-boot make all ARCH=arm
???????
