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求助:AM335x XIP与Fast External boot区别?

大家好:

        在TRM中介绍有两种NOR FLASH启动方式:XIP与Fast External boot,这两种启动方式有什么具体区别吗?我看到通过NORFLASH启动要把MLO放在0x08000000位置上,我们目前NORflash是32M的打算把uboot、uImage、rootfs都放在NORFLASH上,这样放可以吗?谢谢!

  • NOR启动的时候因为能够直接片内执行,所以不再是使用MLO, u-boot.img。如果你用的是Linux SDK的话,需要在编译UBOOT的时候使用am335x_evm_norboot的配置选项。编译成功后出现的u-boot.bin即为UBOOT的启动文件,烧到NOR Flash后,选择XIP启动后,他会在NOR内直接运行,而不是需要拷贝到RAM上面再去执行。

    只要空间够大,把UBOOT,kernel,FS 都放上去是可以的。

  • 我看到在uboot有这样的定义:

    #if defined(CONFIG_NOR) && !defined(CONFIG_NOR_BOOT)

    static struct module_pin_mux bone_norcape_pin_mux[] = {
     {OFFSET(lcd_data0), MODE(1) | PULLUDEN | RXACTIVE},     /* NOR_A0 */
     {OFFSET(lcd_data1), MODE(1) | PULLUDEN | RXACTIVE},     /* NOR_A1 */
     {OFFSET(lcd_data2), MODE(1) | PULLUDEN | RXACTIVE},     /* NOR_A2 */
     {OFFSET(lcd_data3), MODE(1) | PULLUDEN | RXACTIVE},     /* NOR_A3 */
     {OFFSET(lcd_data4), MODE(1) | PULLUDEN | RXACTIVE},     /* NOR_A4 */
     {OFFSET(lcd_data5), MODE(1) | PULLUDEN | RXACTIVE},     /* NOR_A5 */
     {OFFSET(lcd_data6), MODE(1) | PULLUDEN | RXACTIVE},     /* NOR_A6 */
     {OFFSET(lcd_data7), MODE(1) | PULLUDEN | RXACTIVE},     /* NOR_A7 */
     {OFFSET(lcd_vsync), MODE(1) | PULLUDEN | RXACTIVE},     /* NOR_A8 */
     {OFFSET(lcd_hsync), MODE(1) | PULLUDEN | RXACTIVE},     /* NOR_A9 */
     {OFFSET(lcd_pclk), MODE(1)| PULLUDEN | RXACTIVE},       /* NOR_A10 */
     {OFFSET(lcd_ac_bias_en), MODE(1)| PULLUDEN | RXACTIVE}, /* NOR_A11 */
     {OFFSET(lcd_data8), MODE(1) | PULLUDEN | RXACTIVE},     /* NOR_A12 */
     {OFFSET(lcd_data9), MODE(1) | PULLUDEN | RXACTIVE},     /* NOR_A13 */
     {OFFSET(lcd_data10), MODE(1) | PULLUDEN | RXACTIVE},    /* NOR_A14 */
     {OFFSET(lcd_data11), MODE(1) | PULLUDEN | RXACTIVE},    /* NOR_A15 */
     {OFFSET(lcd_data12), MODE(1) | PULLUDEN | RXACTIVE},    /* NOR_A16 */
     {OFFSET(lcd_data13), MODE(1) | PULLUDEN | RXACTIVE},    /* NOR_A17 */
     {OFFSET(lcd_data14), MODE(1) | PULLUDEN | RXACTIVE},    /* NOR_A18 */
     {OFFSET(lcd_data15), MODE(1) | PULLUDEN | RXACTIVE},    /* NOR_A19 */
     {OFFSET(gpmc_ad0), MODE(0) | PULLUDEN | RXACTIVE},      /* NOR_AD0 */
     {OFFSET(gpmc_ad1), MODE(0) | PULLUDEN | RXACTIVE},      /* NOR_AD1 */
     {OFFSET(gpmc_ad2), MODE(0) | PULLUDEN | RXACTIVE},      /* NOR_AD2 */
     {OFFSET(gpmc_ad3), MODE(0) | PULLUDEN | RXACTIVE},      /* NOR_AD3 */
     {OFFSET(gpmc_ad4), MODE(0) | PULLUDEN | RXACTIVE},      /* NOR_AD4 */
     {OFFSET(gpmc_ad5), MODE(0) | PULLUDEN | RXACTIVE},      /* NOR_AD5 */
     {OFFSET(gpmc_ad6), MODE(0) | PULLUDEN | RXACTIVE},      /* NOR_AD6 */
     {OFFSET(gpmc_ad7), MODE(0) | PULLUDEN | RXACTIVE},      /* NOR_AD7 */
     {OFFSET(gpmc_ad8), MODE(0) | PULLUDEN | RXACTIVE},      /* NOR_AD8 */
     {OFFSET(gpmc_ad9), MODE(0) | PULLUDEN | RXACTIVE},      /* NOR_AD9 */
     {OFFSET(gpmc_ad10), MODE(0) | PULLUDEN | RXACTIVE},     /* NOR_AD10 */
     {OFFSET(gpmc_ad11), MODE(0) | PULLUDEN | RXACTIVE},     /* NOR_AD11 */
     {OFFSET(gpmc_ad12), MODE(0) | PULLUDEN | RXACTIVE},     /* NOR_AD12 */
     {OFFSET(gpmc_ad13), MODE(0) | PULLUDEN | RXACTIVE},     /* NOR_AD13 */
     {OFFSET(gpmc_ad14), MODE(0) | PULLUDEN | RXACTIVE},     /* NOR_AD14 */
     {OFFSET(gpmc_ad15), MODE(0) | PULLUDEN | RXACTIVE},     /* NOR_AD15 */

     {OFFSET(gpmc_csn0), (MODE(0) | PULLUDEN) | RXACTIVE},   /* NOR_CE */
     {OFFSET(gpmc_advn_ale), (MODE(0) | PULLUDEN) | RXACTIVE}, /* NOR_ADVN_ALE */
     {OFFSET(gpmc_oen_ren), (MODE(0) | PULLUDEN | RXACTIVE)},/* NOR_OE */
     {OFFSET(gpmc_be0n_cle), (MODE(0) | PULLUDEN | RXACTIVE)},/* NOR_BE0N_CLE */
     {OFFSET(gpmc_wen), (MODE(0) | PULLUDEN | RXACTIVE)},    /* NOR_WEN */
     {OFFSET(gpmc_wait0), (MODE(0) | RXACTIVE | PULLUDEN)}, /* NOR WAIT */
     {-1},
    };

    目前我们项目是用NORFLASAH启动并且KERNEL与ROOTFS都保存在同这一块NORFLASH上,所以把这个定义改为:

    #if defined(CONFIG_NOR) && defined(CONFIG_NOR_BOOT),可以这样直接用吗?