之前编译出来的二进制,能用nandflash加载吗?不能,是吧,这就对啦。为什么不能呢?因为,代码中没有加从nandflash启动所需要的代码。因此,这就是我们今天码字的由来。
1.先修改cpu/arm1176/start.S文件,修改代码如下:
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#ifndef CONFIG_NAND_SPL
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/*
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* flush v4 I/D caches
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*/
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mov r0, #0
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mcr p15, 0, r0, c7, c7, 0 /* flush v3/v4 cache */
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mcr p15, 0, r0, c8, c7, 0 /* flush v4 TLB */
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/*
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* disable MMU stuff and caches
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*/
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mrc p15, 0, r0, c1, c0, 0
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bic r0, r0, #0x00002300 @ clear bits 13, 9:8 (--V- --RS)
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bic r0, r0, #0x00000087 @ clear bits 7, 2:0 (B--- -CAM)
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orr r0, r0, #0x00000002 @ set bit 2 (A) Align
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orr r0, r0, #0x00001000 @ set bit 12 (I) I-Cache
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/* Prepare to disable the MMU */
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adr r1, mmu_disable_phys
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/* We presume we're within the first 1024 bytes */
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and r1, r1, #0x3fc
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ldr r2, _TEXT_PHY_BASE
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ldr r3, =0xfff00000
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and r2, r2, r3
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orr r2, r2, r1
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b mmu_disable
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.align 5
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/* Run in a single cache-line */
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mmu_disable:
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mcr p15, 0, r0, c1, c0, 0
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nop
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nop
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mov pc, r2
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#endif
更改为:
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#ifndef CONFIG_NAND_SPL
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/*
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* flush v4 I/D caches
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*/
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mov r0, #0
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mcr p15, 0, r0, c7, c7, 0 /* flush v3/v4 cache */
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mcr p15, 0, r0, c8, c7, 0 /* flush v4 TLB */
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/*
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* disable MMU stuff and caches
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*/
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mrc p15, 0, r0, c1, c0, 0
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bic r0, r0, #0x00002300 @ clear bits 13, 9:8 (--V- --RS)
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bic r0, r0, #0x00000087 @ clear bits 7, 2:0 (B--- -CAM)
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orr r0, r0, #0x00000002 @ set bit 2 (A) Align
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orr r0, r0, #0x00001000 @ set bit 12 (I) I-Cache
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#if 0
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/* Prepare to disable the MMU */
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adr r1, mmu_disable_phys
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/* We presume we're within the first 1024 bytes */
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and r1, r1, #0x3fc
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ldr r2, _TEXT_PHY_BASE
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ldr r3, =0xfff00000
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and r2, r2, r3
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orr r2, r2, r1
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b mmu_disable
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.align 5
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/* Run in a single cache-line */
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mmu_disable:
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mcr p15, 0, r0, c1, c0, 0
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nop
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nop
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mov pc, r2
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#endif
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#endif
找到lowlevel_init在其下面添加如下代码:
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bl lowlevel_init /* go setup pll,mux,memory */
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/*
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* When we already run in ram, we don't need to relocate U-Boot
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* and actually, memory controller mest to configured before U-Boot
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* is running in ram.
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*/
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ldr r0, =0xff000fff
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bic r1, pc, r0 /*r0 <- current base addr of code*/
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ldr r2, _TEXT_BASE /*r1 <- original base addr in ram*/
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bic r2, r2 ,r0 /*ro <- current base addr of code*/
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cmp r1, r2 /*compare r1 , r2*/
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beq after_copy /* if r1 == r2 then skip flash copy*/
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#ifdef CONFIG_BOOT_NAND
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mov r0, #0x1000
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bl copy_from_nand
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#endif
简述一下:
bic是位清除指令:就是r0中的值取反与pc值相与存入r1,且r1值为0;此时,_TEXT_BASE的值不是0x57e00000就是0xc7e00000;那么执行完bic r2, r2, r0之后r2就为0x00e00000;然后比较r1,r2如果相等则跳转到after_copy;很显然不相等,执行下面的函数copy_from_nand;这个就是从nandflash中拷贝到内存的函数。
在
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#ifdef CONFIG_ENABLE_MMU
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_mmu_table_base:
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.word mmu_table
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#endif
上面这些代码的下面加上如下代码:
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#ifndef CONFIG_NAND_SPL
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/*
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* we assume that cache operation is done before. (eg. cleanup_before_linux())
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* actually, we don't need to do anything about cache if not use d-cache in
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* U-Boot. So, in this function we clean only MMU. by scsuh
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*
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* void theLastJump(void *kernel, int arch_num, uint boot_params);
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*/
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/*
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* copy U-Boot to SDRAM and jump to ram (from NAND or OneNAND)
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* r0: size to be compared
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* Load 1'st 2blocks to RAM because U-boot's size is larger than 1block(128k) size
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*/
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.globl copy_from_nand
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copy_from_nand:
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mov r10, lr /* save return address */
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mov r9, r0
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/* get ready to call C functions */
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ldr sp, _TEXT_PHY_BASE /* setup temp stack pointer */
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sub sp, sp, #12
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mov fp, #0 /* no previous frame, so fp=0 */
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mov r9, #0x1000
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bl copy_uboot_to_ram
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3: tst r0, #0x0
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bne copy_failed
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ldr r0, =0x0c000000
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ldr r1, _TEXT_PHY_BASE
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1: ldr r3, [r0], #4
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ldr r4, [r1], #4
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teq r3, r4
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bne compare_failed /* not matched */
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subs r9, r9, #4
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bne 1b
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4: mov lr, r10 /* all is OK */
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mov pc, lr
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copy_failed:
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nop /* copy from nand failed */
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b copy_failed
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compare_failed:
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nop /* compare failed */
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b compare_failed
2.在cpu/arm1176/目录下面添加文件nand_cp.c。文件内容如下:
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#include <common.h>
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#ifdef CONFIG_S3C64XX
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#include <asm/io.h>
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#include <linux/mtd/nand.h>
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#include <asm/arch/s3c6410.h>
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static int nandll_read_page(uchar *buf, ulong addr, int large_block)
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{
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int i;
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int page_size = 512;
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if (large_block == 1)
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{
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page_size = 2048;
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}
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if(large_block == 2)
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{
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page_size = 4096;
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}
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NAND_ENABLE_CE();
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NFCMD_REG = NAND_CMD_READ0;
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NFADDR_REG = 0; /*Write address*/
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if(large_block)
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{
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NFADDR_REG = 0;
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}
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NFADDR_REG = addr & 0xff;
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NFADDR_REG = (addr >> 8) & 0xff;
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NFADDR_REG = (addr >> 16) & 0xff;
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if (large_block)
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{
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NFCMD_REG = NAND_CMD_READSTART;
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}
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NF_TRANSRnB();
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for(i=0; i < page_size; i++)
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{
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*buf++ = NFDATA8_REG;
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}
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NAND_DISABLE_CE();
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return 0;
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}
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static int nandll_read_blocks (ulong dst_addr, ulong size, int large_block)
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{
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uchar *buf = (uchar *)dst_addr;
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int i;
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uint page_shift = 9;
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if (large_block==1)
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page_shift = 11;
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/* Read pages */
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if(large_block==2)
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page_shift = 12;
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if(large_block == 2)
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{
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/* Read pages */
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for (i = 0; i < 4; i++, buf+=(1<<(page_shift-1)))
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{
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nandll_read_page(buf, i, large_block);
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}
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/* Read pages */
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for (i = 4; i < (0x3c000>>page_shift); i++, buf+=(1<<page_shift))
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{
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nandll_read_page(buf, i, large_block);
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}
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}
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else
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{
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for (i = 0; i < (0x3c000>>page_shift); i++, buf+=(1<<page_shift))
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{
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nandll_read_page(buf, i, large_block);
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}
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}
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return 0;
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}
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int copy_uboot_to_ram(void)
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{
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int large_block = 0;
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int i;
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vu_char id;
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/*
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NFCONT_REG = ( *( (volatile u32 *) (0x70200004) ) )
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NFCONT 0x70200004 读/写NAND Flash 控制寄存器
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[0]1:NAND Flash 控制器使能
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*/
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NAND_ENABLE_CE();
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NFCMD_REG = NAND_CMD_READID;
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/*
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NFADDR_REG = ( *( (volatile u32 *) (0x7020000C) ) )
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NFADDR 0x7020000C NAND Flash 地址设置寄存器 */
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NFADDR_REG = 0x00;
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-
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/*
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NFDATA8_REG = ( *( (vu_char *) (0x70200010) ) )
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NFDATA 0x70200010 读/写NAND Flash 数据寄存器
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NAND Flash 读/烧写数据值用于I/O
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*/
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/* wait for a while */
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for (i=0; i<200; i++);
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id = NFDATA8_REG;
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id = NFDATA8_REG;
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if (id > 0x80)
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large_block = 1;
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if(id == 0xd5)
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large_block = 2;
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/* read NAND Block.
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* 128KB ->240KB because of U-Boot size increase. by scsuh
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* So, read 0x3c000 bytes not 0x20000(128KB).
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*/
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/*CONFIG_SYS_PHY_UBOOT_BASE = 0x57e0 0000
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0x3 c000 = 1M
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*/
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return nandll_read_blocks(CONFIG_SYS_PHY_UBOOT_BASE, 0x3c000, large_block);
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}
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#endif
3.修改cpu/arm1176/makefile文件中
4.修改cpu/arm1176/u-boot.lds文件中
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.text :
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{
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cpu/arm1176/start.o (.text)
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cpu/arm1176/s3c64xx/cpu_init.o (.text)
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board/samsung/smdk6410/lowlevel_init.o (.text)
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cpu/arm1176/nand_cp.o (.text)
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lib_arm/board.o (.text)
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*(.text)
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}
5.修改board/samsung/smdk6410/u-boot-nand.lds文件中
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.text :
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{
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cpu/arm1176/start.o (.text)
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cpu/arm1176/s3c64xx/cpu_init.o (.text)
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board/samsung/smdk6410/lowlevel_init.o (.text)
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cpu/arm1176/nand_cp.o (.text)
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lib_arm/board.o (.text)
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*(.text)
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}
6.修改nand_spl/board/samsung/smdk6410/Makefile文件中
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# from SoC directory
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$(obj)cpu_init.S:
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@rm -f $@
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@ln -s $(TOPDIR)/cpu/arm1176/s3c64xx/cpu_init.S $@
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# from from cpu directory
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$(obj)nand_cp.c:
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@rm -f $@
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@ln -s $(TOPDIR)/cpu/arm1176/nand_cp.c $@
7.修改根目录下u-boot.lds文件
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.text :
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{
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cpu/arm1176/start.o (.text)
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cpu/arm1176/s3c64xx/cpu_init.o (.text)
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board/samsung/smdk6410/lowlevel_init.o (.text)
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cpu/arm1176/nand_cp.o (.text)
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lib_arm/board.o (.text)
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*(.text)
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}
8.修改include/configs/sdmk6410.h文件
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#if !defined(CONFIG_NAND_SPL) && (TEXT_BASE >= 0xc0000000)
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#define CONFIG_ENABLE_MMU
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#ifdef CONFIG_ENABLE_MMU
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#define virt_to_phys(x) virt_to_phy_smdk6410(x)
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#else
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#define virt_to_phys(x) (x)
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#endif
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#endif
添加nand_pc.c中用到的那些宏定义
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#define NAND_DISABLE_CE() (NFCONT_REG |= (1 << 1))
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#define NAND_ENABLE_CE() (NFCONT_REG &= ~(1 << 1))
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#define NF_TRANSRnB() do { while(!(NFSTAT_REG & (1 << 0))); } while(0)
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#define CFG_PHY_UBOOT_BASE CONFIG_SYS_PHY_UBOOT_BASE
9.再次编译。使用make smdk6410_config; make ;生成u-boot-nand.bin,放到开发板上。
这次能够从nandflash启动了。^@^
附加:通过网络烧写到nandflash;
tftp 50000000 u-boot-nand.bin;
nand erase;/*擦除nandflash*/
nand scrub;/*标记坏块*/
nand write 50000000 0 40000 /*写在0~40000 地址之间*/
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