u-boot-2010-06在mini2440上的移植(三)

三．添加对Nor Flash的支持

通常，在嵌入式bootloader中，有两种方式来引导启动内核：从Nor Flash启动和从Nand Flash启动。u-boot中默认是从Nor Flash启动，再从上一节这个运行结果图中看，还发现几个问题：第一，我开发板的Nor Flash是2M的，而这里显示的是512kB；第二，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？为什么会有这些错误信息呢？这是因为我们还没有添加对我们自己的Nor Flash的支持，u-boot默认的是其他型号的Nor Flash，而我们的Nor Flash的型号是SST39VF1601。

下面我们一一来解决这些问题，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：

#gedit include/configs/mini2440.h //修改命令行前的名字和Nor Flash参数部分的定义

#define CONFIG_SYS_PROMPT   "[Backkom@2440]#"     /*-----------------------------------------------------------------------  * FLASH and environment organization  */ #if 0    //注释掉下面两个类型的Nor Flash设置，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 */ #define CONFIG_SST_39VF1601  1 #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 + 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 + 0x070000) //addr of environment #endif #ifdef CONFIG_SST_39VF1601               //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，对其//进行操作有两种方式：块方式和扇区方式。现采用扇区方式(sector)，1 sector = 2Kword = 4Kbyte，//所以2M的Nor Flash共有512个sector #define CONFIG_ENV_ADDR   (CONFIG_SYS_FLASH_BASE + 0x040000) //暂设置环境变量的 //地址为0x040000(即：256Kb) #endif

然后添加对我们mini2440开发板上2M的Nor Flash(型号为SST39VF1601)的支持。在u-boot中对Nor Flash的操作分别有初始化、擦除和写入，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，修改代码如下：

#gedit board/samsung/my2440/flash.c

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

修改完后重新编译u-boot，下载到RAM中运行结果如下图：