【Linux 移植】——4、移植 u-boot-2012.04.01 之支持NAND启动

三、移植 u-boot-2012.04.01 之支持NAND启动

需要进行修改和添加的文件：

1、添加的文件：init.c 包含NAND Flash 的相关配置

board/samsung/smdk2440目录, 修改Makefile

2、需要修改的文件：

a、去掉-pie选项，修改arch/arm/config.mk

b、start.S

c、smdk2440.h

d、common.h

e、board.c

f、arch/arm/cpu/u-boot.lds

1、添加的文件：init.c

init.c 代码如下：

/* NAND FLASH控制器 */
#define NFCONF (*((volatile unsigned long *)0x4E000000))
#define NFCONT (*((volatile unsigned long *)0x4E000004))
#define NFCMMD (*((volatile unsigned char *)0x4E000008))
#define NFADDR (*((volatile unsigned char *)0x4E00000C))
#define NFDATA (*((volatile unsigned char *)0x4E000010))
#define NFSTAT (*((volatile unsigned char *)0x4E000020))

/* GPIO */
#define GPHCON              (*(volatile unsigned long *)0x56000070)
#define GPHUP               (*(volatile unsigned long *)0x56000078)

/* UART registers*/
#define ULCON0              (*(volatile unsigned long *)0x50000000)
#define UCON0               (*(volatile unsigned long *)0x50000004)
#define UFCON0              (*(volatile unsigned long *)0x50000008)
#define UMCON0              (*(volatile unsigned long *)0x5000000c)
#define UTRSTAT0            (*(volatile unsigned long *)0x50000010)
#define UTXH0               (*(volatile unsigned char *)0x50000020)
#define URXH0               (*(volatile unsigned char *)0x50000024)
#define UBRDIV0             (*(volatile unsigned long *)0x50000028)

#define TXD0READY   (1<<2)

void nand_read_ll(unsigned int addr, unsigned char *buf, unsigned int len);

static int isBootFromNorFlash(void)
{
	volatile int *p = (volatile int *)0;
	int val;

	val = *p;
	*p = 0x12345678;
	if (*p == 0x12345678)
	{
		/* 写成功, 是nand启动 */
		*p = val;
		return 0;
	}
	else
	{
		/* NOR不能像内存一样写 */
		return 1;
	}
}

void copy_code_to_sdram(unsigned char *src, unsigned char *dest, unsigned int len)
{	
	int i = 0;

	/* 如果是NOR启动 */
	if (isBootFromNorFlash())
	{
		while (i < len)
		{
			dest[i] = src[i];
			i++;
		}
	}
	else
	{
		//nand_init();
		nand_read_ll((unsigned int)src, dest, len);
	}
}

void clear_bss(void)
{
	extern int __bss_start, __bss_end__;
	int *p = &__bss_start;

	for (; p < &__bss_end__; p++)
		*p = 0;
}

void nand_init_ll(void)
{
#define TACLS   0
#define TWRPH0  1
#define TWRPH1  0
	/* 设置时序 */
	NFCONF = (TACLS<<12)|(TWRPH0<<8)|(TWRPH1<<4);
	/* 使能NAND Flash控制器, 初始化ECC, 禁止片选 */
	NFCONT = (1<<4)|(1<<1)|(1<<0);	
}

static void nand_select(void)
{
	NFCONT &= ~(1<<1);	
}

static void nand_deselect(void)
{
	NFCONT |= (1<<1);	
}

static void nand_cmd(unsigned char cmd)
{
	volatile int i;
	NFCMMD = cmd;
	for (i = 0; i < 10; i++);
}

static void nand_addr(unsigned int addr)
{
	unsigned int col  = addr % 2048;
	unsigned int page = addr / 2048;
	volatile int i;

	NFADDR = col & 0xff;
	for (i = 0; i < 10; i++);
	NFADDR = (col >> 8) & 0xff;
	for (i = 0; i < 10; i++);

	NFADDR  = page & 0xff;
	for (i = 0; i < 10; i++);
	NFADDR  = (page >> 8) & 0xff;
	for (i = 0; i < 10; i++);
	NFADDR  = (page >> 16) & 0xff;
	for (i = 0; i < 10; i++);	
}

static void nand_wait_ready(void)
{
	while (!(NFSTAT & 1));
}

static unsigned char nand_data(void)
{
	return NFDATA;
}

void nand_read_ll(unsigned int addr, unsigned char *buf, unsigned int len)
{
	int col = addr % 2048;
	int i = 0;

	/* 1. 选中 */
	nand_select();

	while (i < len)
	{
		/* 2. 发出读命令00h */
		nand_cmd(0x00);

		/* 3. 发出地址(分5步发出) */
		nand_addr(addr);

		/* 4. 发出读命令30h */
		nand_cmd(0x30);

		/* 5. 判断状态 */
		nand_wait_ready();

		/* 6. 读数据 */
		for (; (col < 2048) && (i < len); col++)
		{
			buf[i] = nand_data();
			i++;
			addr++;
		}

		col = 0;
	}

	/* 7. 取消选中 */		
	nand_deselect();
}

同时在 board/samsung/smdk2440目录, 修改Makefile

Makefile：28: COBJS:= smdk2440.o init.o

2、需要修改的文件：

a、去掉-pie选项，不需要附加“*(.rel*)”、“*(.dynsm)”等信息

命令：grep "\-pie" * -nR
arch/x86/config.mk:43:LDFLAGS_FINAL += --gc-sections -pie
arch/arm/config.mk:75:LDFLAGS_u-boot += -pie
doc/README.arm-relocation:3:At arch level: add linker flag -pie

然后输入命令： vim arch/arm/config.mk

去掉/config.mk去掉75行LDFLAGS_u-boot += -pie

b、修改start.S 参考以前写的start.S 修改代码

前一篇我们对u-boot 进行了时钟、SDRAM 以及串口的相关设定；这一篇的目的是要让u-boot 支持NAND 启动。

在进行是时钟设定之后需要对重定向的代码进行修改：

        ldr	sp, =(CONFIG_SYS_INIT_SP_ADDR)	
	bic	sp, sp, #7 /* 8-byte alignment for ABI compliance */    

	/* 重定位 : 把bootloader本身的代码从flash复制到它的链接地址去 */	
	bl	nand_init_ll	
	mov r0, #0	
	ldr   r1, _TEXT_BASE	
	ldr    r2, _bss_start_ofs		
	bl    copy_code_to_sdram	
	bl    clear_bss	
	ldr pc, = board_init_f

	/* Set stackpointer in internal RAM to call board_init_f */
call_board_init_f:	

	ldr	r0,=0x00000000	
	bl	board_init_f	


	ldr   r1, _TEXT_BASE	
	bl    board_init_r

同时对将CONFIG_SYS_TEXT_BASE修改为0x33f80000

自己写了重定位，就去掉它写的重定位函数
注释掉掉board.c中board_init_f中//relocate_code(addr_sp, id, addr);
删掉start.S中下面不需要的代码

/*------------------------------------------------------------------------------*/
/*
* 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:
mov r4, r0 /* save addr_sp */
mov r5, r1 /* save addr of gd */
mov r6, r2 /* save addr of destination */
/* Set up the stack */
stack_setup:
mov sp, r4
adr r0, _start
cmp r0, r6
moveq r9, #0 /* no relocation. relocation offset(r9) = 0 */
beq clear_bss /* skip relocation */
mov r1, r6 /* r1 <- scratch for copy_loop */
ldr r3, _bss_start_ofs
add r2, r0, r3 /* r2 <- source end address */
copy_loop:
ldmia r0!, {r9-r10} /* copy from source address [r0] */
stmia r1!, {r9-r10} /* copy to target address [r1] */
cmp r0, r2 /* until source end address [r2] */
blo copy_loop
#ifndef CONFIG_SPL_BUILD
/*
* fix .rel.dyn relocations
*/
ldr r0, _TEXT_BASE /* r0 <- Text base */
sub r9, r6, r0 /* r9 <- relocation offset */
ldr r10, _dynsym_start_ofs /* r10 <- sym table ofs */
add r10, r10, r0 /* r10 <- sym table in FLASH */
ldr r2, _rel_dyn_start_ofs /* r2 <- rel dyn start ofs */
add r2, r2, r0 /* r2 <- rel dyn start in FLASH */
ldr r3, _rel_dyn_end_ofs /* r3 <- rel dyn end ofs */
add r3, r3, r0 /* r3 <- rel dyn end in FLASH */
fixloop:
ldr r0, [r2] /* r0 <- location to fix up, IN FLASH! */
add r0, r0, r9 /* r0 <- location to fix up in RAM */
ldr r1, [r2, #4]
and r7, r1, #0xff
cmp r7, #23 /* relative fixup? */
beq fixrel
cmp r7, #2 /* absolute fixup? */
beq fixabs
/* ignore unknown type of fixup */
b fixnext
fixabs:
/* absolute fix: set location to (offset) symbol value */
mov r1, r1, LSR #4 /* r1 <- symbol index in .dynsym */
add r1, r10, r1 /* r1 <- address of symbol in table */
ldr r1, [r1, #4] /* r1 <- symbol value */
add r1, r1, r9 /* r1 <- relocated sym addr */
b fixnext
fixrel:
/* relative fix: increase location by offset */
ldr r1, [r0]
add r1, r1, r9
fixnext:
str r1, [r0]
add r2, r2, #8 /* each rel.dyn entry is 8 bytes */
cmp r2, r3
blo fixloop
#endif
clear_bss:
#ifndef CONFIG_SPL_BUILD
ldr r0, _bss_start_ofs
ldr r1, _bss_end_ofs
mov r4, r6 /* reloc addr */
add r0, r0, r4
add r1, r1, r4
mov r2, #0x00000000 /* clear */
clbss_l:cmp r0, r1 /* clear loop... */
bhs clbss_e /* if reached end of bss, exit */
str r2, [r0]
add r0, r0, #4
b clbss_l
clbss_e:
bl coloured_LED_init
bl red_led_on
#endif

c、smdk2440.h

上一篇我们在 smdk2440.h 定义了CONFIG_S3C2440 并且注释了CONFIG_S3C2410

注释了 #define CONFIG_CMD_NAND

前面我们已经对smdk2440.h 的#define CONFIG_SYS_TEXT_BASE 进行了修改

还需要修改的：

注释掉 #define CONFIG_YAFFS2，解决nand_info 没有定义的错误。

d、common.h

修改include/common.h 276：

void board_init_f (ulong) __attribute__ ((noreturn));

改为unsigned int board_init_f (ulong);

e、board.c

259：将void board_init_f(ulong bootflag)

修改为 unsigned int board_init_f(ulong bootflag)

372：修改如下

//addr -= gd->mon_len;
//addr &= ~(4096 - 1);
addr = _TEXT_BASE;//**add return sp to start.s

439：修改如下

//relocate_code(addr_sp, id, addr);
return (unsigned int) id;// add it

f、arch/arm/cpu/u-boot.lds

修改链接脚本，确保重定位之前的代码编译在最前面

在arch/arm/cpu/u-boot.lds 38:增加如下

board/samsung/smdk2440/libsmdk2440.o (.text)

3、重新配置、编译

make distclean
make smdk2440_config
make

4、烧写、测试

记住这里是烧到NAND，我用NOR Flash里的u-boot烧写，拨到NOR Flash启动，设置串口 115200 8 n 1

U-Boot 2012.04.01 (Oct 05 2015 - 17:08:15)

CPUID: 32440001
FCLK:      400 MHz
HCLK:      100 MHz
PCLK:       50 MHz
DRAM:  64 MiB
WARNING: Caches not enabled

这个结果是加了补丁之后出现的！我按照视频操作之后，注释了 #define CONFIG_YAFFS2，发现编译出来的.bin 文件只有三百多K，烧进去没有出现这个结果，问题正在排查。。

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【Linux 移植】——4、移植 u-boot-2012.04.01 之支持NAND启动

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