四十二.移植bootm命令
0.一开始tftp能下载东西，但是很慢，做的调整有
（1）将下载地址改写成局部变量，并且每次都利用当前块编号进行重定位
（2）加上了原版u-boot里dm9000发送函数里发送前后都要清除发送标志
（3）取消了老师说的要对包进行判断，实际上不判断效果还要好一点，那一部分，要求只要在空读前后有20微妙的时间间隔就好了，经我实际测试，我的开发板确实只用空读一次就满足该条件。
（4）取消了中断处理函数里之前为了验证进的是什么中断的打印部分。时的不容易丢包，不然一直在中断，当下一个包来的时候还未跳出中断，会有丢包现象，最后导致传输失败。
2.uImage和zImage的区别是uImage比后者多了一个头部信息，里面包含了OS类型，幻数，文件类型，压缩方式（从而进行解压缩），
3.找到内核的起始地址
要和tftp下载的目标地址一样。
4.设置启动参数
一开始都要先设置hdr的两个成员，在针对不同的参数类型（flag），去填写其他参数
struct tag_header {
unsigned int size;
unsigned int tag;
};
struct tag {
struct tag_header hdr;
union {
struct tag_core core;
struct tag_mem32 mem;
struct tag_cmdline cmdline;
} u;
};
4.1 核心参数
struct tag_core {
unsigned int flags; /* bit 0 = read-only */
unsigned int pagesize;
unsigned int rootdev;
};
void setup_start_tag()
{
params = (struct tag*)ATAGS_START_ADDR;
params->hdr.tag = ATAG_CORE;
params->hdr.size = tag_size(tag_core);
params->u.core.flags = 0;
params->u.core.pagesize = 4096;
params->u.core.rootdev = 0;
params = tag_next(params);
}
4.2内存参数
struct tag_mem32 {
unsigned int size;
unsigned int start; /* physical start address */
};
void setup_memory_tags()
{
params->hdr.tag = ATAG_MEM;
params->hdr.size = tag_size(tag_mem32);
params->u.mem.start = SDRAM_START_ADDR;
params->u.mem.size = SDRAM_SIZE;
params = tag_next(params);
}
4.3命令行参数
struct tag_cmdline {
char cmdline[1]; /* this is the minimum size */
};
void setup_commandline_tag()
{
params->hdr.tag = ATAG_CMDLINE;
params->hdr.size = (sizeof (struct tag_header) + strlen(cmdline) + 1 + 3) >> 2;
strcpy(params->u.cmdline.cmdline, cmdline);
params = tag_next(params);
}
4.4结束标志
void setup_end_tag()
{
params->hdr.tag = ATAG_NONE;
params->hdr.size = 0;
}
5.将CPU机器码和启动参数地址传给内核，启动内核
kernel_entry(0,2520,ATAGS_START_ADDR);
这个函数原型和实现在linux内核，所以只要给这个函数指针指定启动参数起始地址，linux就会一句这些参数启动内核。
6.总的启动函数
void boot_linux()
{
/*1.传递内核起始地址*/
kernel_entry = (void (*)(int, int, uint))LINUX_START_ADDR;
/*2.设置核心参数*/
setup_start_tag();
/*3.设置内存参数*/
setup_memory_tags();
/*4.设置命令行参数*/
setup_commandline_tag();
/*5.写入参数结束标志*/
setup_end_tag();
/*6.传入机器码启动内核*/
kernel_entry(0,2520,ATAGS_START_ADDR); //用的mini6410的ID====2250。mini2440的ID是1999。tiny6410原本是2251，但是我的zImage是mini6410的内核文件。
}
7.结合前面的tftp的实现，对放在windows上的内核文件进行下载
下载完成
输入数字2启动内核
内核启动完成
6410代码
//#define unsigned int unsigned int;
struct tag_header {
unsigned int size;
unsigned int tag;
};
struct tag_core {
unsigned int flags; /* bit 0 = read-only */
unsigned int pagesize;
unsigned int rootdev;
};
struct tag_mem32 {
unsigned int size;
unsigned int start; /* physical start address */
};
struct tag_cmdline {
char cmdline[1]; /* this is the minimum size */
};
struct tag {
struct tag_header hdr;
union {
struct tag_core core;
struct tag_mem32 mem;
struct tag_cmdline cmdline;
} u;
};
boot.c
#include "string.h"
#include "atag.h"
#include "common.h"
#define uint unsigned int
#define LINUX_START_ADDR 0x51000000
#define ATAGS_START_ADDR 0x50000100
#define SDRAM_START_ADDR 0x50000000
#define SDRAM_SIZE 0x0FF00000
#define ATAG_NONE 0x00000000
#define ATAG_CORE 0x54410001
#define ATAG_MEM 0x54410002
#define ATAG_CMDLINE 0x54410009
#define tag_size(type) ((sizeof(struct tag_header) + sizeof(struct type)) >> 2)
#define tag_next(t) ((struct tag *)((unsigned int *)(t) + (t)->hdr.size))
const char* cmdline = "console=ttySAC0,115200 init=/init root=/dev/nfs rw nfsroot=192.168.1.112:/NFS/rootfs_qtopia_qt4 ip=192.168.1.30:192.168.1.112:192.168.1.1:255.255.255.0:XiaoJunjun:eth0:off";
//const char* cmdline = "console=ttySAC0,115200 init=/init";
void (*kernel_entry)(int, int, uint);
struct tag* params = NULL;
void setup_start_tag()
{
params = (struct tag*)ATAGS_START_ADDR;
params->hdr.tag = ATAG_CORE;
params->hdr.size = tag_size(tag_core);
params->u.core.flags = 0;
params->u.core.pagesize = 4096;
params->u.core.rootdev = 0;
params = tag_next(params);
}
void setup_memory_tags()
{
params->hdr.tag = ATAG_MEM;
params->hdr.size = tag_size(tag_mem32);
params->u.mem.start = SDRAM_START_ADDR;
params->u.mem.size = SDRAM_SIZE;
params = tag_next(params);
}
void setup_commandline_tag()
{
params->hdr.tag = ATAG_CMDLINE;
params->hdr.size = (sizeof (struct tag_header) + strlen(cmdline) + 1 + 3) >> 2;
strcpy(params->u.cmdline.cmdline, cmdline);
params = tag_next(params);
}
void setup_end_tag()
{
params->hdr.tag = ATAG_NONE;
params->hdr.size = 0;
}
void boot_linux()
{
/*1.传递内核起始地址*/
kernel_entry = (void (*)(int, int, uint))LINUX_START_ADDR;
/*2.设置核心参数*/
setup_start_tag();
/*3.设置内存参数*/
setup_memory_tags();
/*4.设置命令行参数*/
setup_commandline_tag();
/*5.写入参数结束标志*/
setup_end_tag();
/*6.传入机器码启动内核*/
kernel_entry(0,2520,ATAGS_START_ADDR); //用的mini6410的ID====2250。mini2440的ID是1999。tiny6410原本是2251，但是我的zImage是mini6410的内核文件。
}
/****************************
@File:main.c
@
@Tiny6410裸机下学期代码
@网卡测试文件
@Author:小君君
@****************************/
#include "common.h"
int main(void)
{
int num = 1000;
led_init();//LED的GPIO初始化
button_init();//按键初始化
led_on();//点亮4颗LED
uart_init();//串口初始化
putchar('a');
putchar('\r');
putchar('\n');
putchar('b');
putchar('\r');
putchar('\n');
dma_init();//DMA初始化
dma_start();//启动DMA发送数据到串口
uart_init();//串口再次初始化，使得串口恢复中断或者轮询模式
lcd_init();
lcd_clear_screen(0xFFFFFF);
dm9000_init();
//dm9000_arp();
while(1){
printf("=================================================\n\r");
printf("===================JUN-BOOT======================\n\r");
printf("0.Send the ARP to get yhe host's MAC address\n\r");
printf("1.Download the linux kernel from tftp\n\r");
printf("2.Boot linux OS from SDRAM\n\r");
printf("3.Junjun is a houmorous\n\r");
printf("=================================================\n\r");
printf("===================LCD_TEST======================\n\r");
printf("4.清屏\n\r");
printf("5.画横线\n\r");
printf("6.画竖线\n\r");
printf("7.画十字架\n\r");
printf("8.画同心圆\n\r");
printf("9.AD转换\n\r");
printf("10.Send the ARP to get yhe host's MAC address\n\r");
printf("11.Download the linux kernel from tftp\n\r");
printf("12.Boot linux OS from SDRAM\n\r");
printf(" \n\r");
printf("请输入0-12任意一个数字：\n\r");
scanf("%d",&num);
switch(num){
case 0:
printf("请支持成都国嵌\n\r");
break;
case 1:
printf("国嵌学院=====打造你的嵌入式人生\n\r");
break;
case 2:
printf("学ARM，学Linux，学C++，学安卓，学嵌入式，就到成都国嵌学院\n\r");
break;
case 3:
printf("只要你肯努力，你的明天就会等你！！\n\r");
break;
case 4:
lcd_clear_screen(0x000000);
break;
case 5:
lcd_clear_screen(0x000000);
lcd_draw_hline(HEIGHT/2, 100, WIDTHEIGHT-100, 0xff0000);
break;
case 6:
lcd_clear_screen(0x000000);
lcd_draw_vline(WIDTHEIGHT/2, 50, HEIGHT-50, 0xff0000);
break;
case 7:
lcd_clear_screen(0x000000);
lcd_draw_cross(HEIGHT/2, WIDTHEIGHT/2, 20, 0x777777);
break;
case 8:
lcd_clear_screen(0x000000);
lcd_draw_circle();
break;
case 9:
read_adc(0);
break;
case 10:
arp_request();
break;
case 11:
tftp_request("zImage");//一定要放对位置，而且文件名要一致
break;
case 12:
boot_linux();
break;
default:
printf("只要你肯努力，你的明天就会等你！！\n\r");
break;
}
}
return 0;
}