Uboot在S3C2440上的移植详解（二）NORFLASH启动uboot

2019独角兽企业重金招聘Python工程师标准>>>

4&＃xff09;准备进入u-boot的第二阶段&＃xff08;在u-boot中添加对我们开发板上Nor Flash的支持&＃xff09;。

通常&＃xff0c;在嵌入式bootloader中&＃xff0c;有两种方式来引导启动内核&＃xff1a;从Nor Flash启动和从Nand Flash启动。u-boot中默认是从Nor Flash启动&＃xff0c;再从上一节这个运行结果图中看&＃xff0c;还发现几个问题&＃xff1a;第一&＃xff0c;我开发板的Nor Flash是2M的&＃xff0c;而这里显示的是512kB&＃xff1b;第二&＃xff0c;出现Warning - bad CRC, using default environment的警告信息。不是u-boot默认是从Nor Flash启动的吗&＃xff1f;为什么会有这些错误信息呢&＃xff1f;这是因为我们还没有添加对我们自己的Nor Flash的支持&＃xff0c;u-boot默认的是其他型号的Nor Flash&＃xff0c;而我们的Nor Flash的型号是SST39VF1601。另外怎样将命令行提示符前面的SMDK2410变成我自己定义的呢&＃xff1f;

下面我们一一来解决这些问题&＃xff0c;让u-boot完全对我们Nor Flash的支持。首先我们修改头文件代码如下&＃xff1a;

#gedit include/configs/my2440.h //修改命令行前的名字和Nor Flash参数部分的定义

#define CONFIG_SYS_PROMPT "[MY2440]#" //将命令行前的名字改成[MY2440]/*-----------------------------------------------------------------------* FLASH and environment organization*/ #if 0 //注释掉下面两个类型的Nor Flash设置&＃xff0c;因为不是我们所使用的型号 #define CONFIG_AMD_LV400 1 /* uncomment this if you have a LV400 flash */ #define CONFIG_AMD_LV800 1 /* uncomment this if you have a LV800 flash */ #endif#define CONFIG_SYS_MAX_FLASH_BANKS 1 /* max number of memory banks */#ifdef CONFIG_AMD_LV800 #define PHYS_FLASH_SIZE 0x00100000 /* 1MB */ #define CONFIG_SYS_MAX_FLASH_SECT (19) /* max number of sectors on one chip */ #define CONFIG_ENV_ADDR (CONFIG_SYS_FLASH_BASE &＃43; 0x0F0000) /* addr of environment */ #endif #ifdef CONFIG_AMD_LV400 #define PHYS_FLASH_SIZE 0x00080000 /* 512KB */ #define CONFIG_SYS_MAX_FLASH_SECT (11) /* max number of sectors on one chip */ #define CONFIG_ENV_ADDR (CONFIG_SYS_FLASH_BASE &＃43; 0x070000) /* addr of environment */ #endif #define CONFIG_SST_39VF1601 1 //添加mini2440开发板Nor Flash设置 #define PHYS_FLASH_SIZE 0x200000 //我们开发板的Nor Flash是2M #define CONFIG_SYS_MAX_FLASH_SECT (512) //根据SST39VF1601的芯片手册描述&＃xff0c;对其进行操作有两种方式&＃xff1a;块方式和扇区方式。现采用扇区方式(sector)&＃xff0c;1 sector &＃61; 2Kword &＃61; 4Kbyte&＃xff0c;所以2M的Nor Flash共有512个sector #define CONFIG_ENV_ADDR (CONFIG_SYS_FLASH_BASE &＃43; 0x040000) //暂设置环境变量的首地址为0x040000(即&＃xff1a;256Kb)

然后添加对我们mini2440开发板上2M的Nor Flash(型号为SST39VF1601&＃xff0c;注&＃xff1a;本人的mini2440板上是&＃xff1a;s29al016j70tfi02&＃xff0c;容量同样是&＃xff1a;2M)的支持。在u-boot中对Nor Flash的操作分别有初始化、擦除和写入&＃xff0c;所以我们主要修改与硬件密切相关的三个函数flash_init、flash_erase、write_hword&＃xff0c;修改代码如下&＃xff1a;

#gedit board/samsung/my2440/flash.c

//修改定义部分如下&＃xff1a; //#define MAIN_SECT_SIZE 0x10000 #define MAIN_SECT_SIZE 0x1000 //定义为4k&＃xff0c;刚好是一个扇区的大小//#define MEM_FLASH_ADDR1 (*(volatile u16 *)(CONFIG_SYS_FLASH_BASE &＃43; (0x00000555 << 1))) //#define MEM_FLASH_ADDR2 (*(volatile u16 *)(CONFIG_SYS_FLASH_BASE &＃43; (0x000002AA << 1))) #define MEM_FLASH_ADDR1 (*(volatile u16 *)(CONFIG_SYS_FLASH_BASE &＃43;(0x00005555 << 1))) //这两个参数看SST39VF1601手册 #define MEM_FLASH_ADDR2 (*(volatile u16 *)(CONFIG_SYS_FLASH_BASE &＃43;(0x00002AAA << 1)))//修改flash_init函数如下&＃xff1a; #elif defined(CONFIG_AMD_LV800)(AMD_MANUFACT & FLASH_VENDMASK) |(AMD_ID_LV800B & FLASH_TYPEMASK); #elif defined(CONFIG_SST_39VF1601) //在CONFIG_AMD_LV800后面添加CONFIG_SST_39VF1601 (SST_MANUFACT & FLASH_VENDMASK) |(SST_ID_xF1601 & FLASH_TYPEMASK);for (j &＃61; 0; j < flash_info[i].sector_count; j&＃43;&＃43;) {//if (j <&＃61; 3) {// /* 1st one is 16 KB */// if (j &＃61;&＃61; 0) {// flash_info[i].start[j] &＃61; flashbase &＃43; 0;// }// /* 2nd and 3rd are both 8 KB */// if ((j &＃61;&＃61; 1) || (j &＃61;&＃61; 2)) {// flash_info[i].start[j] &＃61; flashbase &＃43; 0x4000 &＃43; (j - 1) * 0x2000;// }// /* 4th 32 KB */// if (j &＃61;&＃61; 3) {// flash_info[i].start[j] &＃61; flashbase &＃43; 0x8000;// }//} else {// flash_info[i].start[j] &＃61; flashbase &＃43; (j - 3) * MAIN_SECT_SIZE;//}flash_info[i].start[j] &＃61; flashbase &＃43; j * MAIN_SECT_SIZE; }//修改flash_print_info函数如下&＃xff1a; case (AMD_MANUFACT & FLASH_VENDMASK):printf ("AMD: ");break; case (SST_MANUFACT & FLASH_VENDMASK): //添加SST39VF1601的printf ("SST: ");break;case (AMD_ID_LV800B & FLASH_TYPEMASK):printf ("1x Amd29LV800BB (8Mbit)\n");break; case (SST_ID_xF1601 & FLASH_TYPEMASK): //添加SST39VF1601的printf ("1x SST39VF1610 (16Mbit)\n");break;//修改flash_erase函数如下&＃xff1a; //if ((info->flash_id & FLASH_VENDMASK) !&＃61; // (AMD_MANUFACT & FLASH_VENDMASK)) { // return ERR_UNKNOWN_FLASH_VENDOR; //} if ((info->flash_id & FLASH_VENDMASK) !&＃61;(SST_MANUFACT & FLASH_VENDMASK)) {return ERR_UNKNOWN_FLASH_VENDOR; }///* wait until flash is ready */ //chip &＃61; 0; //do { // result &＃61; *addr; // /* check timeout */ // if (get_timer_masked () > // CONFIG_SYS_FLASH_ERASE_TOUT) { // MEM_FLASH_ADDR1 &＃61; CMD_READ_ARRAY; // chip &＃61; TMO; // break; // }// if (!chip // && (result & 0xFFFF) & BIT_ERASE_DONE) // chip &＃61; READY;// if (!chip // && (result & 0xFFFF) & BIT_PROGRAM_ERROR) // chip &＃61; ERR; //} while (!chip);//MEM_FLASH_ADDR1 &＃61; CMD_READ_ARRAY;//if (chip &＃61;&＃61; ERR) { // rc &＃61; ERR_PROG_ERROR; // goto outahere; //}//if (chip &＃61;&＃61; TMO) { // rc &＃61; ERR_TIMOUT; // goto outahere; //} while (1) {if ((*addr & 0x40) !&＃61; (*addr & 0x40))continue;if (*addr & 0x80){rc &＃61; ERR_OK;break;} }//修改write_hword函数如下&＃xff1a; MEM_FLASH_ADDR1 &＃61; CMD_UNLOCK1; MEM_FLASH_ADDR2 &＃61; CMD_UNLOCK2; //MEM_FLASH_ADDR1 &＃61; CMD_UNLOCK_BYPASS; MEM_FLASH_ADDR1 &＃61; CMD_PROGRAM; //*addr &＃61; CMD_PROGRAM; *addr &＃61; data;///* wait until flash is ready */ //chip &＃61; 0; //do { // result &＃61; *addr; // /* check timeout */ // if (get_timer_masked () > CONFIG_SYS_FLASH_ERASE_TOUT) { // chip &＃61; ERR | TMO; // break; // }// if (!chip && ((result & 0x80) &＃61;&＃61; (data & 0x80))) // chip &＃61; READY;// if (!chip && ((result & 0xFFFF) & BIT_PROGRAM_ERROR)) { // result &＃61; *addr;// if ((result & 0x80) &＃61;&＃61; (data & 0x80)) // chip &＃61; READY; // else // chip &＃61; ERR; // } //} while (!chip);//*addr &＃61; CMD_READ_ARRAY;//if (chip &＃61;&＃61; ERR || *addr !&＃61; data) // rc &＃61; ERR_PROG_ERROR; while (1) {if ((*addr & 0x40) !&＃61; (*addr & 0x40)) continue;if ((*addr & 0x80) &＃61;&＃61; (data & 0x80)){rc &＃61; ERR_OK;break; } }

修改完后重新编译u-boot&＃xff0c;下载到RAM中运行结果如下图&＃xff1a;

# make my2440_config # make

本人是直接烧写到 NOR FLASH 中的&＃xff0c;运行结果(大致)如下:&＃xff08;注&＃xff1a;本人并没用supervivi&＃xff09;

从运行结果图看&＃xff0c;Nor Flash的大小可以正确检测到了&＃xff0c;命令行前面的名字也由原来的SMDK2410改成我自己定义的[MY2440]了&＃xff0c;但是还会出现bad CRC的警告信息&＃xff0c;其实这并不是什么问题&＃xff0c;只是还没有将环境变量设置到Nor Flash中&＃xff0c;我们执行一下u-boot的&＃xff1a;saveenv命令就可以了。如下图&＃xff1a;