第3阶段 支持nand boot程序修改
1、修改/cpu/arm920t/start.S
1) 删除AT91RM9200使用的LED代码。
#include <config.h>
#include <version.h>
#if defined(CONFIG_AT91RM9200DK)
#include <status_led.h> /*这是针对AT91RM9200DK开发板的。*/
#endif
......
/*
* the actual start code
*/
start_code:
/*
* set the cpu to SVC32 mode
*/
mrs r0,cpsr
bic r0,r0,#0x1f
orr r0,r0,#0xd3
msr cpsr,r0
bl coloured_LED_init
bl red_LED_on
2) 修改寄存器地址定义
#if defined(CONFIG_S3C2400) || defined(CONFIG_S3C2410)|| defined(CONFIG_S3C2440)
/* turn off the watchdog */
#if defined(CONFIG_S3C2400)
#define pWTCON 0x15300000
#define INTMSK 0x14400008 /* Interupt-Controller base addresses */
#define CLKDIVN 0x14800014 /* clock divisor register */
#else
#define pWTCON 0x53000000
#define INTMSK 0x4A000008 /* Interupt-Controller base addresses */
#define INTSUBMSK 0x4A00001C
#define CLKDIVN 0x4C000014 /* clock divisor register */
#define CLK_CTL_BASE 0x4C000000
#define MDIV_405 0x7f << 12
#define PSDIV_405 0x21
#define MDIV_200 0xa1 << 12
#define PSDIV_200 0x31
3) 修改中断禁止部分
#if defined(CONFIG_S3C2410)
ldr r1, =0x7ff /*根据2410芯片手册，INTSUBMSK有11位可用*/
ldr r0, =INTSUBMSK
str r1, [r0]
#if defined(CONFIG_S3C2440)
ldr r1, =0x7fff /*根据2440芯片手册，INTSUBMSK有15位可用*/
4) 修改时钟设置（2440的主频为405MHz。）
# if defined(CONFIG_S3C2440)
/* FCLK:HCLK:PCLK = 1:4:8 */
ldr r0, =CLKDIVN
mov r1, #5
mrc p15, 0, r1, c1, c0, 0 /*read ctrl register */
orr r1, r1, #0xc0000000 /*Asynchronous */
mcr p15, 0, r1, c1, c0, 0 /*write ctrl register */
/*now, CPU clock is 405.00 Mhz */
mov r1, #CLK_CTL_BASE /* */
mov r2, #MDIV_405 /* mpll_405mhz */
add r2, r2, #PSDIV_405 /* mpll_405mhz */
str r2, [r1, #0x04] /* MPLLCON */
/* FCLK:HCLK:PCLK = 1:2:4 */
mov r1, #3
/*now, CPU clock is 202.8 Mhz */
mov r2, #MDIV_200 /* mpll_200mhz */
add r2, r2, #PSDIV_200 /* mpll_200mhz */
str r2, [r1, #0x04]
# endif
#endif /* CONFIG_S3C2400 || CONFIG_S3C2410|| CONFIG_S3C2440 */
5) 将从Nor Flash启动改成从NAND Flash启动。
在以下U－Boot的重定向语句段(作用是将u-boot的源代码从nor flash到sdram中)： （你完全可以把下面的nor flash重定向语句全部干掉）
#ifndef CONFIG_AT91RM9200
#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, r3, r2 /* r2 <- size of armboot */
add r2, r0, r2 /* r2 <- source end address*/
copy_loop:
ldmia {r3-r10} /* copy from source address [r0] */
stmia {r3-r10} /* copy to target address [r1] */
cmp r0, r2 /* until source end addreee [r2] */
ble copy_loop
#endif /* CONFIG_SKIP_RELOCATE_UBOOT */
的前面添加上以下的nand boot代码： #ifdef CONFIG_S3C2440_NAND_BOOT
#define NAND_CTL_BASE 0x4E000000
/* Offset */
#define oNFCONF 0x00
#define oNFCONT 0x04
#define oNFCMD 0x08
#define oNFSTAT 0x20
#define LENGTH_UBOOT 0x40000
@ 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
orr r2, r2, #0x2 @ Flash Memory Chip Disable
@ 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
#ifdef CONFIG_S3C2410_NAND_BOOT
#define oNFCMD 0x04
#define oNFSTAT 0x10
ldr r2, =0xf830 @ initial value
bic r2, r2, #0x800 @ enable chip
mov r2, #0xff @ RESET command
nand1:
tst r2, #0x1
orr r2, r2, #0x800 @ disable chip
在 “ _start_armboot: .word start_armboot ” 后加入：
#define STACK_BASE 0x33f00000
#define STACK_SIZE 0x10000
.align 2
DW_STACK_START: .word STACK_BASE+STACK_SIZE-4
2、 在board/mini2440加入NAND Flash读取函数（start.S中需要的nand_read_ll函数）文件nand_read.c
==================================================================
#include <linux/mtd/nand.h>
#define __REGb(x) (*(volatile unsigned char *)(x))
#define __REGw(x) (*(volatile unsigned short *)(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 NFSTAT_BUSY 1
#define nand_select() (NFCONF &= ~0x800)
#define nand_deselect() (NFCONF |= 0x800)
#define nand_clear_RnB() do {} while (0)
#elif defined(CONFIG_S3C2440)
#define NFCONT __REGi(NF_BASE + 0x4)
#define NFCMD __REGb(NF_BASE + 0x8)
#define NFADDR __REGb(NF_BASE + 0xc)
#define NFDATA __REGb(NF_BASE + 0x10)
#define NFDATA16 __REGw(NF_BASE + 0x10)
#define NFSTAT __REGb(NF_BASE + 0x20)
#define NFSTAT_BUSY (1 << 2)
#define nand_select() (NFCONT &= ~(1 << 1))
#define nand_deselect() (NFCONT |= (1 << 1))
#define nand_clear_RnB() (NFSTAT |= NFSTAT_BUSY)
static inline void nand_wait(void)
{
int i;
while (!(NFSTAT & NFSTAT_BUSY))
for (i=0; i<10; i++);
}
/* configuration for 2410 with 512byte sized flash */
#define NAND_PAGE_SIZE 512
#define BAD_BLOCK_OFFSET 517
#define NAND_BLOCK_MASK (NAND_PAGE_SIZE - 1)
#define NAND_BLOCK_SIZE 0x4000
/* configuration for 2440 with 2048byte sized flash */
#define NAND_5_ADDR_CYCLE
#define NAND_PAGE_SIZE 2048
#define BAD_BLOCK_OFFSET NAND_PAGE_SIZE
#define NAND_BLOCK_SIZE (NAND_PAGE_SIZE * 64)
/* compile time failure in case of an invalid configuration */
#if defined(CONFIG_S3C2410) && (NAND_PAGE_SIZE != 512)
#error "S3C2410 does not support nand page size != 512"
static int is_bad_block(unsigned long i)
unsigned char data;
unsigned long page_num;
/* FIXME: do this twice, for first and second page in block */
nand_clear_RnB();
#if (NAND_PAGE_SIZE == 512)
NFCMD = NAND_CMD_READOOB; /* 0x50 */
NFADDR = BAD_BLOCK_OFFSET & 0xf;
NFADDR = (i >> 9) & 0xff;
NFADDR = (i >> 17) & 0xff;
NFADDR = (i >> 25) & 0xff;
#elif (NAND_PAGE_SIZE == 2048)
page_num = i >> 11; /* addr / 2048 */
NFCMD = NAND_CMD_READ0;
NFADDR = BAD_BLOCK_OFFSET & 0xff;
NFADDR = (BAD_BLOCK_OFFSET >> 8) & 0xff;
NFADDR = page_num & 0xff;
NFADDR = (page_num >> 8) & 0xff;
NFADDR = (page_num >> 16) & 0xff;
NFCMD = NAND_CMD_READSTART;
nand_wait();
data = (NFDATA & 0xff);
if (data != 0xff)
return 1;
return 0;
static int nand_read_page_ll(unsigned char *buf, unsigned long addr)
unsigned short *ptr16 = (unsigned short *)buf;
unsigned int i, page_num;
/* Write Address */
NFADDR = addr & 0xff;
NFADDR = (addr >> 9) & 0xff;
NFADDR = (addr >> 17) & 0xff;
NFADDR = (addr >> 25) & 0xff;
page_num = addr >> 11; /* addr / 2048 */
NFADDR = 0;
#error "unsupported nand page size"
for (i = 0; i < NAND_PAGE_SIZE; i++)
{
*buf = (NFDATA & 0xff);
buf++;
}
return NAND_PAGE_SIZE;
/* 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 */
nand_select();
for (i=0; i<10; i++);
for (i=start_addr; i < (start_addr + size);)
j = nand_read_page_ll(buf, i);
i += j;
buf += j;
/* chip Disable */
nand_deselect();
return 0;
==============================================================
记得修改board/mini2440/Makefile文件,将nand_read.c编译进u-boot。
OBJS := mini2440.o nand_read.o flash.o
3、修改board/mini2440/lowlevel_init.S文件
/* REFRESH parameter */
#define REFEN 0x1 /* Refresh enable */
#define TREFMD 0x0 /* CBR(CAS before RAS)/Auto refresh */
#define Trc 0x3 /* 7clk */
#define Tchr 0x2 /* 3clk */
#define Trp 0x2 /* 4clk */
#define REFCNT 1012
#define Trp 0x0 /* 2clk */
#define REFCNT 0x0459
4、 修改/board/mini2440/mini2440.c
修改其对GPIO和PLL的配置(请参阅开发板的硬件说明和芯片手册)；并针对LCD显示部分和nand flash驱动添加相应的代码： ......
#include <common.h>
#include <s3c2410.h>
#include <video_fb.h>
#if defined(CONFIG_CMD_NAND)
DECLARE_GLOBAL_DATA_PTR;
#define FCLK_SPEED 1
#if FCLK_SPEED==0 /* Fout = 203MHz, Fin = 12MHz for Audio */
#define M_MDIV 0xC3
#define M_PDIV 0x4
#define M_SDIV 0x1
#elif FCLK_SPEED==1 /* Fout = 202.8MHz */
/* Fout = 202.8MHz */
#define M_MDIV 0xA1
#define M_PDIV 0x3
/* Fout = 405MHz */
#define M_MDIV 0x7f
#define M_PDIV 0x2
#define M_SDIV 0x1
#define USB_CLOCK 1
#if USB_CLOCK==0
#define U_M_MDIV 0xA1
#define U_M_PDIV 0x3
#define U_M_SDIV 0x1
#elif USB_CLOCK==1
#define U_M_MDIV 0x48
#define U_M_MDIV 0x38
#define U_M_PDIV 0x2
#define U_M_SDIV 0x2
为连接LED和蜂鸣器的GPIO修改配置寄存器：
int board_init (void):
#if defined(CONFIG_MINI2440)
gpio->GPBCON = 0x00295551;
gpio->GPBCON = 0x00044556;
为引导linux 内核，修改开发板的类型代码：
/* arch number of SMDK2410-Board */
gd->bd->bi_arch_number = MACH_TYPE_SMDK2410;
/* arch number of S3C2440-Board */
gd->bd->bi_arch_number = MACH_TYPE_S3C2440 ;
......为使int board_init (void)设置完成后，LED1和LED2同时亮起，蜂鸣器继续鸣叫，在int board_init (void)的最后添加： ......
icache_enable();
dcache_enable();
#if defined(CONFIG_MINI2440_LED)
gpio->GPBDAT = 0x00000181;
return 0;
5、最后，修改board/mini2440/u-boot.lds文件，在
cpu/arm920t/start.o (.text)
后加上
board/2440/lowlevel_init.o (.text)
board/2440/nand_read.o (.text)
本文转自 zjb_integrated 51CTO博客，原文链接：http://blog.51cto.com/zjbintsystem/211345，如需转载请自行联系原作者
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