分类：
2012-03-24 11:55:07
|
OM1 (Operating Mode 1) |
OM0 (Operating Mode 0) |
Booting ROM Data width |
|
0 |
0 |
Nand Flash Mode |
|
0 |
1 |
16-bit |
|
1 |
0 |
32-bit |
|
1 |
1 |
Test Mode |
| BWSCON | Bit | Description | Initial state |
| DW0 | [2:1] | Indicate data bus width for bank 0 (read only). 01 = 16-bit, 10 = 32-bit The states are selected by OM[1:0] pins |
-------------- |
# define BWSCON 0x48000000
ldr r0,=BWSCON
ldr r0,[r0]
and r0,r0,#6
cmp r0, #0
bne relocate
/****************************/
//nand_boot
//Nand 搬移代码
/****************************/
/****************************/
relocate：
//nor_boot
//Nor 搬移代码
/****************************/
有了上面这段代码，就可以实现双启动了，只要再适当的添加对应的功能我们的uboot就完成了。
（1）判断当前代码位置，如果在内存，直接跳到stack_setup
/*********** CHECK_CODE_POSITION *******************/
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
/********** CHECK_CODE_POSITION ******************/
（2）如果不是在代码当前位置不再内存中，就判断启动的Flash：Nand 或者Nor
/***************** CHECK_BOOT_FLASH *********************/
修改部分：（将Tekkaman Ninja代码修改）
# define BWSCON 0x48000000
ldr r0,=BWSCON
ldr r0,[r0]
ands r0,r0,#6
cmp r0, #0
bne relocate
/***************** CHECK_BOOT_FLASH ***********************/
（3）如果判断是在Nand Flash中启动的话，那么nand Flash搬移代码如下：
定义u-boot在nand flash中存放的长度为#define LENGTH_UBOOT 0x60000，可以方便修改u-boot因为裁剪和增添大小的改变而占的长度。
// copy U-Boot to RAM form Nand Flash
/*********** NAND_BOOT **********************************/
#define LENGTH_UBOOT 0x60000
#define NAND_CTL_BASE 0x4E000000
#ifdef CONFIG_S3C2440
/* Offset */
#define oNFCONF 0x00
#define oNFCONT 0x04
#define oNFCMD 0x08
#define oNFSTAT 0x20
@ reset NAND
mov r1, #NAND_CTL_BASE
ldr r2, =( (7<<12)|(7<<8)|(7<<4)|(0<<0) )
str r2, [r1, #oNFCONF]
ldr r2, [r1, #oNFCONF]
ldr r2, =( (1<<4)|(0<<1)|(1<<0) ) @ Active low CE Control
str r2, [r1, #oNFCONT]
ldr r2, [r1, #oNFCONT]
ldr r2, =(0x6) @ RnB Clear
str r2, [r1, #oNFSTAT]
ldr r2, [r1, #oNFSTAT]
mov r2, #0xff @ RESET command
strb r2, [r1, #oNFCMD]
mov r3, #0 @ wait
nand1:
add r3, r3, #0x1
cmp r3, #0xa
blt nand1
nand2:
ldr r2, [r1, #oNFSTAT] @ wait ready
tst r2, #0x4
beq nand2
ldr r2, [r1, #oNFCONT]
orr r2, r2, #0x2 @ Flash Memory Chip Disable
str r2, [r1, #oNFCONT]
@ 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 U-Boot to RAM
ldr r0, =TEXT_BASE
mov r1, #0x0
mov r2, #LENGTH_UBOOT
bl nand_read_ll
tst r0, #0x0
beq ok_nand_read
bad_nand_read:
loop2:
b loop2 @ infinite loop
ok_nand_read:
@ verify
mov r0, #0
ldr r1, =TEXT_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, r2, #4
beq stack_setup
bne go_next
notmatch:
loop3:
b loop3 @ infinite loop
#endif
#ifdef CONFIG_S3C2410
/* Offset */
#define oNFCONF 0x00
#define oNFCMD 0x04
#define oNFSTAT 0x10
@ reset NAND
mov r1, #NAND_CTL_BASE
ldr r2, =0xf830 @ initial value
str r2, [r1, #oNFCONF]
ldr r2, [r1, #oNFCONF]
bic r2, r2, #0x800 @ enable chip
str r2, [r1, #oNFCONF]
mov r2, #0xff @ RESET command
strb r2, [r1, #oNFCMD]
mov r3, #0 @ wait
nand1:
add r3, r3, #0x1
cmp r3, #0xa
blt nand1
nand2:
ldr r2, [r1, #oNFSTAT] @ wait ready
tst r2, #0x1
beq nand2
ldr r2, [r1, #oNFCONF]
orr r2, r2, #0x800 @ disable chip
str r2, [r1, #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 U-Boot to RAM
ldr r0, =TEXT_BASE
mov r1, #0x0
mov r2, #LENGTH_UBOOT
bl nand_read_ll
tst r0, #0x0
beq ok_nand_read
bad_nand_read:
loop2:
b loop2 @ infinite loop
ok_nand_read:
@ verify
mov r0, #0
ldr r1, =TEXT_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, r2, #4
beq stack_setup
bne go_next
notmatch:
loop3:
b loop3 @ infinite loop
#endif
/*************** NAND_BOOT *******************************/
(4) 如果判断是在Nor Flash中启动的话，那么nor Flash搬移代码如下
// copy U-Boot to RAM form Nor Flash
//#ifndef CONFIG_SKIP_RELOCATE_UBOOT
/***************** NOR_BOOT ****************************/
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, r3, r2 /* r2 <- size of armboot */
add r2, r0, 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
/***************** NOR_BOOT ****************************/
//#endif /* CONFIG_SKIP_RELOCATE_UBOOT */
