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(Board/dave)U-boot之flash初始化完全代码分析

分类： 嵌入式

2010-07-25 09:56:56

U-boot之flash初始化完全代码分析 

一 代码分析
 
1、Board->dave->flash.c
 
#include
#include
#include "../common/flash.c"
#包含必须的头文件
static ulong flash_get_size (vu_long * addr, flash_info_t * info);
static void flash_get_offsets (ulong base, flash_info_t * info);
#声明两个静态函数
 
FLASH初始化
 
unsigned long flash_init (void)
{
#ifdef __DEBUG_START_FROM_SRAM__
    return CFG_DUMMY_FLASH_SIZE;
#如果定义了__DEBUG_START_FROM_SRAM__也就是从ram启动，则返回CFG_DUMMY_FLASH_SIZE
 
#else
    unsigned long size_b0;
    int i;
    /* Init: no FLASHes known */
    for (i=0; i
        flash_info[i].flash_id = FLASH_UNKNOWN;
    }
    #初始标识Flash的bank为FLASH_UNKNOWN
 
    /* Static FLASH Bank configuration here - FIXME XXX */
    size_b0 = flash_get_size((vu_long *)CFG_FLASH_BASE, &flash_info[0]);
    #调用flash_get_size函数，获取flash的大小，存入size_b0
 
    if (flash_info[0].flash_id == FLASH_UNKNOWN) {
        printf ("## Unknown FLASH on Bank 0 - Size = 0x%08lx = %ld MB\n",
            size_b0, size_b0<<20);
    }
    #判断Flash是否是列表中所有的，如果没有，打印信息。具体列表在flash_get_size函数中
 
    /* Setup offsets */
    flash_get_offsets (0, &flash_info[0]);
    #设置起始偏移地址。“0”表示基地址，“&flash_info[0]”bank0的基地址
 
    /* Monitor protection ON by default */
    (void)flash_protect(FLAG_PROTECT_SET,
                -CFG_MONITOR_LEN,
                0xffffffff,
                &flash_info[0]);
    #flash保护，见flash_protect函数
    flash_info[0].size = size_b0;
    #将size_b0存入flash_info[0]
    return (size_b0);
#endif
}
 
 
2、Board->dave->command->flash.c
 
#include
#include
#包含必要的头文件
flash_info_t    flash_info[CFG_MAX_FLASH_BANKS]; /* info for FLASH chips    */
#定义数组flash_info为flash_info_t类型，该类型的定义见3
static int write_word (flash_info_t *info, ulong dest, ulong data);
#声明静态函数
 
 
获取FLASH偏移地址
static void flash_get_offsets (ulong base, flash_info_t *info)
{
    int i;
    short n;
    /* set up sector start address table */
    #设置起始地址表。判断Flash类型，厂商和片名，如果都不符合，则执行else的内容
    if (((info->flash_id & FLASH_VENDMASK) == FLASH_MAN_SST) ||
        ((info->flash_id & FLASH_TYPEMASK) == FLASH_AM640U)) {
        for (i = 0; i < info->sector_count; i++)
        info->start[i] = base + (i * 0x00010000);
    } else if (((info->flash_id & FLASH_TYPEMASK) == FLASH_AMDL322B) ||
           ((info->flash_id & FLASH_TYPEMASK) == FLASH_AMDL323B) ||
           ((info->flash_id & FLASH_TYPEMASK) == FLASH_AM320B) ||
           ((info->flash_id & FLASH_TYPEMASK) == FLASH_AMDL324B)) {
        /* set sector offsets for bottom boot block type    */
        for (i=0; i<8; ++i) {       /*  8 x 8k boot sectors */
            info->start[i] = base;
            base += 8 << 10;
        }
        while (i < info->sector_count) {    /* 64k regular sectors  */
            info->start[i] = base;
            base += 64 << 10;
            ++i;
        }
    } else if (((info->flash_id & FLASH_TYPEMASK) == FLASH_AMDL322T) ||
           ((info->flash_id & FLASH_TYPEMASK) == FLASH_AMDL323T) ||
           ((info->flash_id & FLASH_TYPEMASK) == FLASH_AM320T) ||
           ((info->flash_id & FLASH_TYPEMASK) == FLASH_AMDL324T)) {
        /* set sector offsets for top boot block type       */
        base += info->size;
        i = info->sector_count;
        for (n=0; n<8; ++n) {       /*  8 x 8k boot sectors */
            base -= 8 << 10;
            --i;
            info->start[i] = base;
        }
        while (i > 0) {         /* 64k regular sectors  */
            base -= 64 << 10;
            --i;
            info->start[i] = base;
        }
    } else {
        if (info->flash_id & FLASH_BTYPE) {
        /* set sector offsets for bottom boot block type    */
        info->start[0] = base + 0x00000000;
        info->start[1] = base + 0x00004000;
        info->start[2] = base + 0x00006000;
        info->start[3] = base + 0x00008000;
        for (i = 4; i < info->sector_count; i++) {
            info->start[i] = base + (i * 0x00010000) - 0x00030000;
        }
        } else {
        /* set sector offsets for top boot block type       */
        #如果都不是以上的类型，设置物理片段的起始地址
        i = info->sector_count - 1;
        info->start[i--] = base + info->size - 0x00004000;
        info->start[i--] = base + info->size - 0x00006000;
        info->start[i--] = base + info->size - 0x00008000;
        for (; i >= 0; i--) {
            info->start[i] = base + i * 0x00010000;
        }
        }
    }
}
 
 
FLASH信息打印输出
void flash_print_info  (flash_info_t *info)
{
    int i;
    int k;
    int size;
    int erased;
    volatile unsigned long *flash;
 
    if (info->flash_id == FLASH_UNKNOWN) {
        printf ("missing or unknown FLASH type\n");
        return;
    }
    switch (info->flash_id & FLASH_VENDMASK) {
    case FLASH_MAN_AMD: printf ("AMD ");        break;
    case FLASH_MAN_FUJ: printf ("FUJITSU ");        break;
    case FLASH_MAN_SST: printf ("SST ");        break;
    case FLASH_MAN_STM: printf ("ST  ");    break;
    default:        printf ("Unknown Vendor "); break;
    }
    switch (info->flash_id & FLASH_TYPEMASK) {
    case FLASH_AM400B:  printf ("AM29LV400B (4 Mbit, bottom boot sect)\n");
                break;
    case FLASH_AM400T:  printf ("AM29LV400T (4 Mbit, top boot sector)\n");
                break;
    case FLASH_AM800B:  printf ("AM29LV800B (8 Mbit, bottom boot sect)\n");
                break;
    case FLASH_AM800T:  printf ("AM29LV800T (8 Mbit, top boot sector)\n");
                break;
    case FLASH_AM160B:  printf ("AM29LV160B (16 Mbit, bottom boot sect)\n");
                break;
    case FLASH_AM160T:  printf ("AM29LV160T (16 Mbit, top boot sector)\n");
                break;
    case FLASH_AM320T:  printf ("AM29LV320T (32 M, top sector)\n");
                break;
    case FLASH_AM320B:  printf ("AM29LV320B (32 M, bottom sector)\n");
                break;
    case FLASH_AMDL322T:    printf ("AM29DL322T (32 M, top sector)\n");
                break;
    case FLASH_AMDL322B:    printf ("AM29DL322B (32 M, bottom sector)\n");
                break;
    case FLASH_AMDL323T:    printf ("AM29DL323T (32 M, top sector)\n");
                break;
    case FLASH_AMDL323B:    printf ("AM29DL323B (32 M, bottom sector)\n");
                break;
    case FLASH_AM640U:  printf ("AM29LV640D (64 M, uniform sector)\n");
                break;
    case FLASH_SST800A: printf ("SST39LF/VF800 (8 Mbit, uniform sector size)\n");
                break;
    case FLASH_SST160A: printf ("SST39LF/VF160 (16 Mbit, uniform sector size)\n");
                break;
    case FLASH_STMW320DT:   printf ("M29W320DT (32 M, top sector)\n");
                break;
    default:        printf ("Unknown Chip Type\n");
                break;
    }
    printf ("  Size: %ld MB in %d Sectors\n",
        info->size >> 20, info->sector_count);
    printf ("  Sector Start Addresses:");
    for (i=0; isector_count; ++i) {
#ifdef CFG_FLASH_EMPTY_INFO
        /*
         * Check if whole sector is erased
         */
        if (i != (info->sector_count-1))
          size = info->start[i+1] - info->start[i];
        else
          size = info->start[0] + info->size - info->start[i];
        erased = 1;
        flash = (volatile unsigned long *)info->start[i];
        size = size >> 2;        /* divide by 4 for longword access */
        for (k=0; k
          {
            if (*flash++ != 0xffffffff)
              {
            erased = 0;
            break;
              }
          }
 
        if ((i % 5) == 0)
            printf ("\n   ");
        /* print empty and read-only info */
        printf (" %08lX%s%s",
            info->start[i],
            erased ? " E" : "  ",
            info->protect[i] ? "RO " : "   ");
#else
        if ((i % 5) == 0)
            printf ("\n   ");
        printf (" %08lX%s",
            info->start[i],
            info->protect[i] ? " (RO)" : "     ");
#endif
 
    }
    printf ("\n");
    return;
}
 
 
获取FLASH大小
static ulong flash_get_size (vu_long *addr, flash_info_t *info)
{
    short i;
    short n;
    CFG_FLASH_WORD_SIZE value;
    ulong base = (ulong)addr;
    volatile CFG_FLASH_WORD_SIZE *addr2 = (CFG_FLASH_WORD_SIZE *)addr;
#CFG_FLASH_WORD_SIZE等于unsign short在B2.h中定义
 
    debug("[%s, %d] Entering ...\n", __FUNCTION__, __LINE__);
    /* Write auto select command: read Manufacturer ID */
    addr2[CFG_FLASH_ADDR0] = (CFG_FLASH_WORD_SIZE)0x00AA00AA;
    addr2[CFG_FLASH_ADDR1] = (CFG_FLASH_WORD_SIZE)0x00550055;
    addr2[CFG_FLASH_ADDR0] = (CFG_FLASH_WORD_SIZE)0x00900090;
#B2.h中定义#define CFG_FLASH_ADDR0 0x5555   
#define CFG_FLASH_ADDR1 0x2AAA   
  
 
  <<<<<<无法理解？>>>>>>
    value = addr2[CFG_FLASH_READ0];
#获取flash的厂商ID
    switch (value) {
    case (CFG_FLASH_WORD_SIZE)AMD_MANUFACT:
        info->flash_id = FLASH_MAN_AMD;
        break;
    case (CFG_FLASH_WORD_SIZE)FUJ_MANUFACT:
        info->flash_id = FLASH_MAN_FUJ;
        break;
    case (CFG_FLASH_WORD_SIZE)SST_MANUFACT:
        info->flash_id = FLASH_MAN_SST;
        break;
    case (CFG_FLASH_WORD_SIZE)STM_MANUFACT:
        info->flash_id = FLASH_MAN_STM;
        break;
    default:
        info->flash_id = FLASH_UNKNOWN;
        info->sector_count = 0;
        info->size = 0;
        return (0);         /* no or unknown flash  */
    }
    value = addr2[CFG_FLASH_READ1];     /* device ID        */
   
 
 #获取flash的设备ID
    switch (value) {
    case (CFG_FLASH_WORD_SIZE)AMD_ID_LV400T:
        info->flash_id += FLASH_AM400T;
        info->sector_count = 11;
        info->size = 0x00080000;
        break;              /* => 0.5 MB        */
    case (CFG_FLASH_WORD_SIZE)AMD_ID_LV400B:
        info->flash_id += FLASH_AM400B;
        info->sector_count = 11;
        info->size = 0x00080000;
        break;              /* => 0.5 MB        */
    case (CFG_FLASH_WORD_SIZE)AMD_ID_LV800T:
        info->flash_id += FLASH_AM800T;
        info->sector_count = 19;
        info->size = 0x00100000;
        break;              /* => 1 MB      */
    case (CFG_FLASH_WORD_SIZE)AMD_ID_LV800B:
        info->flash_id += FLASH_AM800B;
        info->sector_count = 19;
        info->size = 0x00100000;
        break;              /* => 1 MB      */
    case (CFG_FLASH_WORD_SIZE)AMD_ID_LV160T:
        info->flash_id += FLASH_AM160T;
        info->sector_count = 35;
        info->size = 0x00200000;
        break;              /* => 2 MB      */
    case (CFG_FLASH_WORD_SIZE)AMD_ID_LV160B:
        info->flash_id += FLASH_AM160B;
        info->sector_count = 35;
        info->size = 0x00200000;
        break;              /* => 2 MB      */
    case (CFG_FLASH_WORD_SIZE)STM_ID_29W320DT:
        info->flash_id += FLASH_STMW320DT;
        info->sector_count = 67;
        info->size = 0x00400000;  break; /* => 4 MB  */
    case (CFG_FLASH_WORD_SIZE)AMD_ID_LV320T:
        info->flash_id += FLASH_AM320T;
        info->sector_count = 71;
        info->size = 0x00400000;  break; /* => 4 MB  */
    case (CFG_FLASH_WORD_SIZE)AMD_ID_LV320B:
        info->flash_id += FLASH_AM320B;
        info->sector_count = 71;
        info->size = 0x00400000;  break; /* => 4 MB  */
    case (CFG_FLASH_WORD_SIZE)AMD_ID_DL322T:
        info->flash_id += FLASH_AMDL322T;
        info->sector_count = 71;
        info->size = 0x00400000;  break; /* => 4 MB  */
    case (CFG_FLASH_WORD_SIZE)AMD_ID_DL322B:
        info->flash_id += FLASH_AMDL322B;
        info->sector_count = 71;
        info->size = 0x00400000;  break; /* => 4 MB  */
    case (CFG_FLASH_WORD_SIZE)AMD_ID_DL323T:
        info->flash_id += FLASH_AMDL323T;
        info->sector_count = 71;
        info->size = 0x00400000;  break; /* => 4 MB  */
    case (CFG_FLASH_WORD_SIZE)AMD_ID_DL323B:
        info->flash_id += FLASH_AMDL323B;
        info->sector_count = 71;
        info->size = 0x00400000;  break; /* => 4 MB  */
    case (CFG_FLASH_WORD_SIZE)AMD_ID_LV640U:
        info->flash_id += FLASH_AM640U;
        info->sector_count = 128;
        info->size = 0x00800000;  break; /* => 8 MB  */
    case (CFG_FLASH_WORD_SIZE)SST_ID_xF800A:
        info->flash_id += FLASH_SST800A;
        info->sector_count = 16;
        info->size = 0x00100000;
        break;              /* => 1 MB      */
    case (CFG_FLASH_WORD_SIZE)SST_ID_xF160A:
        info->flash_id += FLASH_SST160A;
        info->sector_count = 32;
        info->size = 0x00200000;
        break;              /* => 2 MB      */
    default:
        info->flash_id = FLASH_UNKNOWN;
        return (0);         /* => no or unknown flash */
    }
   #根据开发板Flash的情况，设定id,sector_count,size参数，若无则皆为0
    /* set up sector start address table */
  
 #设定起始地址表，与flash_get_offsets中的相同
    if (((info->flash_id & FLASH_VENDMASK) == FLASH_MAN_SST) ||
        ((info->flash_id & FLASH_TYPEMASK) == FLASH_AM640U)) {
        for (i = 0; i < info->sector_count; i++)
        info->start[i] = base + (i * 0x00010000);
    } else if (((info->flash_id & FLASH_TYPEMASK) == FLASH_AMDL322B) ||
           ((info->flash_id & FLASH_TYPEMASK) == FLASH_AMDL323B) ||
           ((info->flash_id & FLASH_TYPEMASK) == FLASH_AM320B) ||
           ((info->flash_id & FLASH_TYPEMASK) == FLASH_AMDL324B)) {
        /* set sector offsets for bottom boot block type    */
        for (i=0; i<8; ++i) {       /*  8 x 8k boot sectors */
            info->start[i] = base;
            base += 8 << 10;
        }
        while (i < info->sector_count) {    /* 64k regular sectors  */
            info->start[i] = base;
            base += 64 << 10;
            ++i;
        }
    } else if (((info->flash_id & FLASH_TYPEMASK) == FLASH_AMDL322T) ||
           ((info->flash_id & FLASH_TYPEMASK) == FLASH_AMDL323T) ||
           ((info->flash_id & FLASH_TYPEMASK) == FLASH_AM320T) ||
           ((info->flash_id & FLASH_TYPEMASK) == FLASH_AMDL324T)) {
        /* set sector offsets for top boot block type       */
        base += info->size;
        i = info->sector_count;
        for (n=0; n<8; ++n) {       /*  8 x 8k boot sectors */
            base -= 8 << 10;
            --i;
            info->start[i] = base;
        }
        while (i > 0) {         /* 64k regular sectors  */
            base -= 64 << 10;
            --i;
            info->start[i] = base;
        }
    } else if ((info->flash_id & FLASH_TYPEMASK) == FLASH_STMW320DT) {
        /* set sector offsets for top boot block type       */
        base += info->size;
        i = info->sector_count;
        /*  1 x 16k boot sector */
        base -= 16 << 10;
        --i;
        info->start[i] = base;
        /*  2 x 8k  boot sectors */
        for (n=0; n<2; ++n) {
            base -= 8 << 10;
            --i;
            info->start[i] = base;
 

        }
 

        /*  1 x 32k boot sector */
        base -= 32 << 10;
        --i;
        info->start[i] = base;
 
        while (i > 0) {         /* 64k regular sectors  */
            base -= 64 << 10;
            --i;
            info->start[i] = base;
        }
    } else {
        if (info->flash_id & FLASH_BTYPE) {
        /* set sector offsets for bottom boot block type    */
        info->start[0] = base + 0x00000000;
        info->start[1] = base + 0x00004000;
        info->start[2] = base + 0x00006000;
        info->start[3] = base + 0x00008000;
        for (i = 4; i < info->sector_count; i++) {
            info->start[i] = base + (i * 0x00010000) - 0x00030000;
        }
        } else {
        /* set sector offsets for top boot block type       */
        i = info->sector_count - 1;
        info->start[i--] = base + info->size - 0x00004000;
        info->start[i--] = base + info->size - 0x00006000;
        info->start[i--] = base + info->size - 0x00008000;
        for (; i >= 0; i--) {
            info->start[i] = base + i * 0x00010000;
        }
        }
    }
 
 
#检测保护的片段
    for (i = 0; i < info->sector_count; i++) {
        /* read sector protection at sector address, (A7 .. A0) = 0x02 */
        /* D0 = 1 if protected */
        addr2 = (volatile CFG_FLASH_WORD_SIZE *)(info->start[i]);
        if ((info->flash_id & FLASH_VENDMASK) == FLASH_MAN_SST)
          info->protect[i] = 0;
        else
          info->protect[i] = addr2[CFG_FLASH_READ2] & 1;
    }
 
    if (info->flash_id != FLASH_UNKNOWN) {
        addr2 = (CFG_FLASH_WORD_SIZE *)info->start[0];
        *addr2 = (CFG_FLASH_WORD_SIZE)0x00F000F0;   /* reset bank */
    }
    return (info->size);
}
 
 
 
擦除函数
int flash_erase (flash_info_t *info, int s_first, int s_last)
{
    volatile CFG_FLASH_WORD_SIZE *addr = (CFG_FLASH_WORD_SIZE *)(info->start[0]);
    volatile CFG_FLASH_WORD_SIZE *addr2;
    int flag, prot, sect, l_sect;
    ulong start, now, last;
    int i;
    if ((s_first < 0) || (s_first > s_last)) {
        if (info->flash_id == FLASH_UNKNOWN) {
            printf ("- missing\n");
        } else {
            printf ("- no sectors to erase\n");
        }
        return 1;
    }
    if (info->flash_id == FLASH_UNKNOWN) {
        printf ("Can't erase unknown flash type - aborted\n");
        return 1;
    }
    prot = 0;
    for (sect=s_first; sect<=s_last; ++sect) {
        if (info->protect[sect]) {
            prot++;
        }
    }
    if (prot) {
        printf ("- Warning: %d protected sectors will not be erased!\n",
            prot);
    } else {
        printf ("\n");
    }
    l_sect = -1;
    /* Disable interrupts which might cause a timeout here */
    flag = disable_interrupts();
    /* Start erase on unprotected sectors */
    for (sect = s_first; sect<=s_last; sect++) {
        if (info->protect[sect] == 0) { /* not protected */
            addr2 = (CFG_FLASH_WORD_SIZE *)(info->start[sect]);
            if ((info->flash_id & FLASH_VENDMASK) == FLASH_MAN_SST) {
            addr[CFG_FLASH_ADDR0] = (CFG_FLASH_WORD_SIZE)0x00AA00AA;
            addr[CFG_FLASH_ADDR1] = (CFG_FLASH_WORD_SIZE)0x00550055;
            addr[CFG_FLASH_ADDR0] = (CFG_FLASH_WORD_SIZE)0x00800080;
            addr[CFG_FLASH_ADDR0] = (CFG_FLASH_WORD_SIZE)0x00AA00AA;
            addr[CFG_FLASH_ADDR1] = (CFG_FLASH_WORD_SIZE)0x00550055;
            addr2[0] = (CFG_FLASH_WORD_SIZE)0x00500050;  /* block erase */
            for (i=0; i<50; i++)
              udelay(1000);  /* wait 1 ms */
            } else {
            if (sect == s_first) {
                addr[CFG_FLASH_ADDR0] = (CFG_FLASH_WORD_SIZE)0x00AA00AA;
                addr[CFG_FLASH_ADDR1] = (CFG_FLASH_WORD_SIZE)0x00550055;
                addr[CFG_FLASH_ADDR0] = (CFG_FLASH_WORD_SIZE)0x00800080;
                addr[CFG_FLASH_ADDR0] = (CFG_FLASH_WORD_SIZE)0x00AA00AA;
                addr[CFG_FLASH_ADDR1] = (CFG_FLASH_WORD_SIZE)0x00550055;
            }
            addr2[0] = (CFG_FLASH_WORD_SIZE)0x00300030;  /* sector erase */
            }
            l_sect = sect;
        }
    }
    /* re-enable interrupts if necessary */
    if (flag)
        enable_interrupts();
    /* wait at least 80us - let's wait 1 ms */
    udelay (1000);
    /*
     * We wait for the last triggered sector
     */
    if (l_sect < 0)
        goto DONE;
    start = get_timer (0);
    last  = start;
    addr = (CFG_FLASH_WORD_SIZE *)(info->start[l_sect]);
    while ((addr[0] & (CFG_FLASH_WORD_SIZE)0x00800080) != (CFG_FLASH_WORD_SIZE)0x00800080) {
        if ((now = get_timer(start)) > CFG_FLASH_ERASE_TOUT) {
            printf ("Timeout\n");
            return 1;
        }
        /* show that we're waiting */
        if ((now - last) > 1000) {  /* every second */
            putc ('.');
            last = now;
        }
    }
DONE:
    /* reset to read mode */
    addr = (CFG_FLASH_WORD_SIZE *)info->start[0];
    addr[0] = (CFG_FLASH_WORD_SIZE)0x00F000F0;  /* reset bank */
 
    printf (" done\n");
    return 0;
}
 
 
 
/*-----------------------------------------------------------------------
 * Copy memory to flash, returns:
 * 0 - OK
 * 1 - write timeout
 * 2 - Flash not erased
 */
 
 
写缓冲函数
int write_buff (flash_info_t *info, uchar *src, ulong addr, ulong cnt)
{
    ulong cp, wp, data;
    int i, l, rc;
 
    wp = (addr & ~3);   /* get lower word aligned address */
 
    /*
     * handle unaligned start bytes
     */
    if ((l = addr - wp) != 0) {
        data = 0;
        for (i=0, cp=wp; i
#ifdef CONFIG_B2
            data = data | ((*(uchar *)cp)<<(8*i));
#else
            data = (data << 8) | (*(uchar *)cp);
#endif
        }
        for (; i<4 && cnt>0; ++i) {
#ifdef CONFIG_B2
            data = data  | ((*src++)<<(8*i));
#else
            data = (data << 8) | *src++;
#endif
            --cnt;
            ++cp;
        }
        for (; cnt==0 && i<4; ++i, ++cp) {
#ifdef CONFIG_B2
            data = data | ((*(uchar *)cp)<<(8*i));
#else
            data = (data << 8) | (*(uchar *)cp);
#endif
        }
 
        if ((rc = write_word(info, wp, data)) != 0) {
            return (rc);
        }
        wp += 4;
    }
 
    /*
     * handle word aligned part
     */
    while (cnt >= 4) {
        data = 0;
#ifdef CONFIG_B2
        data = (*(ulong*)src);
        src += 4;
#else
        for (i=0; i<4; ++i) {
            data = (data << 8) | *src++;
        }
#endif
        if ((rc = write_word(info, wp, data)) != 0) {
            return (rc);
        }
        wp  += 4;
        cnt -= 4;
    }
 
    if (cnt == 0) {
        return (0);
    }
 
    /*
     * handle unaligned tail bytes
     */
    data = 0;
    for (i=0, cp=wp; i<4 && cnt>0; ++i, ++cp) {
#ifdef CONFIG_B2
        data = data  | ((*src++)<<(8*i));
#else
        data = (data << 8) | *src++;
#endif
        --cnt;
    }
    for (; i<4; ++i, ++cp) {
#ifdef CONFIG_B2
        data = data | ((*(uchar *)cp)<<(8*i));
#else
        data = (data << 8) | (*(uchar *)cp);
#endif
    }
 
    return (write_word(info, wp, data));
}
 
/*-----------------------------------------------------------------------
 * Write a word to Flash, returns:
 * 0 - OK
 * 1 - write timeout
 * 2 - Flash not erased
 */
 
 
写字函数
static int write_word (flash_info_t *info, ulong dest, ulong data)
{
    volatile CFG_FLASH_WORD_SIZE *addr2 = (CFG_FLASH_WORD_SIZE *)(info->start[0]);
    volatile CFG_FLASH_WORD_SIZE *dest2 = (CFG_FLASH_WORD_SIZE *)dest;
    volatile CFG_FLASH_WORD_SIZE *data2 = (CFG_FLASH_WORD_SIZE *)&data;
    ulong start;
    int flag;
    int i;
 
    /* Check if Flash is (sufficiently) erased */
    if ((*((volatile ulong *)dest) & data) != data) {
        return (2);
    }
    /* Disable interrupts which might cause a timeout here */
    flag = disable_interrupts();
 
    for (i=0; i<4/sizeof(CFG_FLASH_WORD_SIZE); i++)
      {
        addr2[CFG_FLASH_ADDR0] = (CFG_FLASH_WORD_SIZE)0x00AA00AA;
        addr2[CFG_FLASH_ADDR1] = (CFG_FLASH_WORD_SIZE)0x00550055;
        addr2[CFG_FLASH_ADDR0] = (CFG_FLASH_WORD_SIZE)0x00A000A0;
 
        dest2[i] = data2[i];
 
        /* re-enable interrupts if necessary */
        if (flag)
          enable_interrupts();
 
        /* data polling for D7 */
        start = get_timer (0);
        while ((dest2[i] & (CFG_FLASH_WORD_SIZE)0x00800080) !=
           (data2[i] & (CFG_FLASH_WORD_SIZE)0x00800080)) {
          if (get_timer(start) > CFG_FLASH_WRITE_TOUT) {
        return (1);
          }
        }
      }
 
    return (0);
}
 
 
3、include->flash.h
 
typedef struct {
    ulong   size;           /* total bank size in bytes     */
    ushort  sector_count;       /* number of erase units        */
    ulong   flash_id;       /* combined device & manufacturer code  */
    ulong   start[CFG_MAX_FLASH_SECT];   /* physical sector start addresses */
    uchar   protect[CFG_MAX_FLASH_SECT]; /* sector protection status    */
#ifdef CFG_FLASH_CFI
    uchar   portwidth;      /* the width of the port        */
    uchar   chipwidth;      /* the width of the chip        */
    ushort  buffer_size;        /* # of bytes in write buffer       */
    ulong   erase_blk_tout;     /* maximum block erase timeout      */
    ulong   write_tout;     /* maximum write timeout        */
    ulong   buffer_write_tout;  /* maximum buffer write timeout     */
    ushort  vendor;         /* the primary vendor id        */
    ushort  cmd_reset;      /* Vendor specific reset command    */
    ushort  interface;      /* used for x8/x16 adjustments      */
    ushort  legacy_unlock;      /* support Intel legacy (un)locking */
#endif
} flash_info_t;
4、common->flash.c
#include
#include
 
#if !defined(CFG_NO_FLASH)
extern flash_info_t  flash_info[]; /* info for FLASH chips */
 
 
FLASH保护
void flash_protect (int flag, ulong from, ulong to, flash_info_t *info)
{
    ulong b_end = info->start[0] + info->size - 1;  /* bank end address */
    short s_end = info->sector_count - 1;   /* index of last sector */
    int i;
 
    debug ("flash_protect %s: from 0x%08lX to 0x%08lX\n",
        (flag & FLAG_PROTECT_SET) ? "ON" :
            (flag & FLAG_PROTECT_CLEAR) ? "OFF" : "???",
        from, to);
 
    /* Do nothing if input data is bad. */
    if (info->sector_count == 0 || info->size == 0 || to < from) {
        return;
    }
   
#无用数据时什么都不做
    /* There is nothing to do if we have no data about the flash
     * or the protect range and flash range don't overlap.
     */
    if (info->flash_id == FLASH_UNKNOWN ||
        to < info->start[0] || from > b_end) {
        return;
    }
   
 #写的数据超出范围，或者无数据时，什么都不做
    for (i=0; isector_count; ++i) {
        ulong end;      /* last address in current sect */
 
        end = (i == s_end) ? b_end : info->start[i + 1] - 1;
 
        /* Update protection if any part of the sector
         * is in the specified range.
         */
        if (from <= end && to >= info->start[i]) {
            if (flag & FLAG_PROTECT_CLEAR) {
#if defined(CFG_FLASH_PROTECTION)
                flash_real_protect(info, i, 0);
#else
                info->protect[i] = 0;
#endif  /* CFG_FLASH_PROTECTION */
                debug ("protect off %d\n", i);
            }
            else if (flag & FLAG_PROTECT_SET) {
#if defined(CFG_FLASH_PROTECTION)
                flash_real_protect(info, i, 1);
#else
                info->protect[i] = 1;
#endif  /* CFG_FLASH_PROTECTION */
                debug ("protect on %d\n", i);
            }
        }
    }
}
 
 
写地址到info
 
flash_info_t *addr2info (ulong addr)
{
#ifndef CONFIG_SPD823TS
    flash_info_t *info;
    int i;
 
    for (i=0, info=&flash_info[0]; i
        if (info->flash_id != FLASH_UNKNOWN &&
            addr >= info->start[0] &&
            /* WARNING - The '- 1' is needed if the flash
             * is at the end of the address space, since
             * info->start[0] + info->size wraps back to 0.
             * Please don't change this unless you understand this.
             */
            addr <= info->start[0] + info->size - 1) {
            return (info);
        }
        #判断数据是否有用，若有用，则返回info
    }
#endif /* CONFIG_SPD823TS */
    return (NULL);
}
 
 
 
/*-----------------------------------------------------------------------
 * Copy memory to flash.
 * Make sure all target addresses are within Flash bounds,
 * and no protected sectors are hit.
 * Returns:
 * ERR_OK          0 - OK
 * ERR_TIMOUT      1 - write timeout
 * ERR_NOT_ERASED  2 - Flash not erased
 * ERR_PROTECTED   4 - target range includes protected sectors
 * ERR_INVAL       8 - target address not in Flash memory
 * ERR_ALIGN       16 - target address not aligned on boundary
 *          (only some targets require alignment)
 */
 
 
 
写FLASH
int flash_write (char *src, ulong addr, ulong cnt)
{
#ifdef CONFIG_SPD823TS
    return (ERR_TIMOUT);    /* any other error codes are possible as well */
#else
    int i;
    ulong         end        = addr + cnt - 1;
    flash_info_t *info_first = addr2info (addr);
    flash_info_t *info_last  = addr2info (end );
    flash_info_t *info;
 
    if (cnt == 0) {
        return (ERR_OK);
    }
 
    if (!info_first || !info_last) {
        return (ERR_INVAL);
    }
 
    for (info = info_first; info <= info_last; ++info) {
        ulong b_end = info->start[0] + info->size;  /* bank end addr */
        short s_end = info->sector_count - 1;
        for (i=0; isector_count; ++i) {
            ulong e_addr = (i == s_end) ? b_end : info->start[i + 1];
 
            if ((end >= info->start[i]) && (addr < e_addr) &&
                (info->protect[i] != 0) ) {
                return (ERR_PROTECTED);
            }
        }
    }
 
    /* finally write data to flash */
    for (info = info_first; info <= info_last && cnt>0; ++info) {
        ulong len;
 
        len = info->start[0] + info->size - addr;
        if (len > cnt)
            len = cnt;
        if ((i = write_buff(info, (uchar *)src, addr, len)) != 0) {
            return (i);
        }
        cnt  -= len;
        addr += len;
        src  += len;
    }
    return (ERR_OK);
#endif /* CONFIG_SPD823TS */
}
 
 
错误类型显示
void flash_perror (int err)
{
    switch (err) {
    case ERR_OK:
        break;
    case ERR_TIMOUT:
        puts ("Timeout writing to Flash\n");
        break;
    case ERR_NOT_ERASED:
        puts ("Flash not Erased\n");
        break;
    case ERR_PROTECTED:
        puts ("Can't write to protected Flash sectors\n");
        break;
    case ERR_INVAL:
        puts ("Outside available Flash\n");
        break;
    case ERR_ALIGN:
        puts ("Start and/or end address not on sector boundary\n");
        break;
    case ERR_UNKNOWN_FLASH_VENDOR:
        puts ("Unknown Vendor of Flash\n");
        break;
    case ERR_UNKNOWN_FLASH_TYPE:
        puts ("Unknown Type of Flash\n");
        break;
    case ERR_PROG_ERROR:
        puts ("General Flash Programming Error\n");
        break;
    default:
        printf ("%s[%d] FIXME: rc=%d\n", __FILE__, __LINE__, err);
        break;
    }
}
 
 
 
二 执行流程
 
 
在lib_arm->board.c中的start_armboot函数是第2阶段的起始，我们从这里开始分析：
1)       flash_init()被调用；
2)       初始化所有的BANK为FLASH_UNKNOW；
3)       调用flash_get_size()。通过判断FLASH类型，获得FLASH的大小，并且返回info->size，存放入size_b0；
4)       调用flash_get_offsets()设置BANK起始地址表，无返回；
5)       调用flash_protect()判断写入信息是否可用
6)       返回size_b0
7)       调用display_flash_config (size)；定义为static void display_flash_config (ulong size){puts ("Flash: ");print_size (size, "\n");}  打印FLASH容量信息。
 
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