U-boot之flash初始化完全代码分析_#ifndef start_from_sram

一 代码分析

 

1、Board->dave->flash.c

#include <common.h>

#include <asm/hardware.h>

#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<CFG_MAX_FLASH_BANKS; ++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 <common.h>

#include <asm/processor.h>

#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;