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TQ335x(AM335x) Uboot移植–(1)让uboot在TQ335x上跑起来!

2017年09月15日 Uboot 暂无评论 阅读 1,885 次

最近移植了下u-boot-2014.10到TQ335x,我是基于am335x evm进行移植,先只要让uboot在TQ335x上面运行,需要修改的地方并不是很多。由于TI的am335x evm开发使用了一个eeprom保存了板载配置信息,用来区分不同板子的型号的,而TQ335x没有这个eeprom,因此,需要修改eeprom相关的部分,使u-boot适应TQ335x开发板。


单板:TQ335x Core-c

编译环境:ubuntu12.04

uboot版本:2014.10


1、使用source insight查看代码,很容易发现,所有获取板载配置的部分都是通过读取eeprom获得的,因此,首选修改read_eeprom(board/ti/am335x/board.c)函数,具体的修改如下:

static int read_eeprom(struct am335x_baseboard_id *header)  
{  
#if 1  
    strcpy(header->name, "TQ335x");  
#else  
    /* Check if baseboard eeprom is available */  
    if (i2c_probe(CONFIG_SYS_I2C_EEPROM_ADDR)) {  
        puts("Could not probe the EEPROM; something fundamentally "  
            "wrong on the I2C bus.\n");  
        return -ENODEV;  
    }  
  
    /* read the eeprom using i2c */  
    if (i2c_read(CONFIG_SYS_I2C_EEPROM_ADDR, 0, 2, (uchar *)header,  
             sizeof(struct am335x_baseboard_id))) {  
        puts("Could not read the EEPROM; something fundamentally"  
            " wrong on the I2C bus.\n");  
        return -EIO;  
    }  
  
    if (header->magic != 0xEE3355AA) {  
        /* 
         * read the eeprom using i2c again, 
         * but use only a 1 byte address 
         */  
        if (i2c_read(CONFIG_SYS_I2C_EEPROM_ADDR, 0, 1, (uchar *)header,  
                 sizeof(struct am335x_baseboard_id))) {  
            puts("Could not read the EEPROM; something "  
                "fundamentally wrong on the I2C bus.\n");  
            return -EIO;  
        }  
  
        if (header->magic != 0xEE3355AA) {  
            printf("Incorrect magic number (0x%x) in EEPROM\n",  
                    header->magic);  
            return -EINVAL;  
        }  
    }  
#endif  
  
    return 0;  
} 

2、通过上述修改,u-boot不去读取eeprom,而是直接将header的name赋值为"TQ335x",后面可以根据这一配置区分是否为TQ335x开发板。然后是修改get_dpll_ddr_params(board/ti/am335x/board.c)函数,具体的修改内容如下:

const struct dpll_params *get_dpll_ddr_params(void)  
{  
    struct am335x_baseboard_id header;  
  
    enable_i2c0_pin_mux();  
    i2c_init(CONFIG_SYS_OMAP24_I2C_SPEED, CONFIG_SYS_OMAP24_I2C_SLAVE);  
    if (read_eeprom(&header) < 0)  
        puts("Could not get board ID.\n");  
  
    if (board_is_tq335x(&header) || board_is_evm_sk(&header))  
        return &dpll_ddr_evm_sk;  
    else if (board_is_bone_lt(&header))  
        return &dpll_ddr_bone_black;  
    else if (board_is_evm_15_or_later(&header))  
        return &dpll_ddr_evm_sk;  
    else  
        return &dpll_ddr;  
}

3、然后是修改sdram_init(board/ti/am335x/board.c)函数,具体的修改内容如下:

void sdram_init(void)  
{  
    __maybe_unused struct am335x_baseboard_id header;  
  
    if (read_eeprom(&header) < 0)  
        puts("Could not get board ID.\n");  
  
    if (board_is_evm_sk(&header)) {  
        /* 
         * EVM SK 1.2A and later use gpio0_7 to enable DDR3. 
         * This is safe enough to do on older revs. 
         */  
        gpio_request(GPIO_DDR_VTT_EN, "ddr_vtt_en");  
        gpio_direction_output(GPIO_DDR_VTT_EN, 1);  
    }  
  
    if (board_is_evm_sk(&header) || board_is_tq335x(&header))  
        config_ddr(303, &ioregs_evmsk, &ddr3_data,  
               &ddr3_cmd_ctrl_data, &ddr3_emif_reg_data, 0);  
    else if (board_is_bone_lt(&header))  
        config_ddr(400, &ioregs_bonelt,  
               &ddr3_beagleblack_data,  
               &ddr3_beagleblack_cmd_ctrl_data,  
               &ddr3_beagleblack_emif_reg_data, 0);  
    else if (board_is_evm_15_or_later(&header))  
        config_ddr(303, &ioregs_evm15, &ddr3_evm_data,  
               &ddr3_evm_cmd_ctrl_data, &ddr3_evm_emif_reg_data, 0);  
    else  
        config_ddr(266, &ioregs, &ddr2_data,  
               &ddr2_cmd_ctrl_data, &ddr2_emif_reg_data, 0);  
} 

4、然后添加board_is_tq335x函数的具体实现,参考其它类似函数实现即可,由于我们的read_eeprom仅读到了name,其内容是"TQ335x",故可如下实现,在board/ti/am335x/board.h中添加如下内容:

static inline int board_is_tq335x(struct am335x_baseboard_id *header)  
{  
    return !strncmp(header->name, "TQ335x", HDR_NAME_LEN);  
}  

5、最后是修改enable_board_pin_mux(board/ti/am335x/mux.c)函数,具体的修改内容如下:

void enable_board_pin_mux(struct am335x_baseboard_id *header)  
{  
    /* Do board-specific muxes. */  
    if (board_is_bone(header) || board_is_tq335x(header)) {  
        /* Beaglebone pinmux */  
        configure_module_pin_mux(i2c1_pin_mux);  
        configure_module_pin_mux(mii1_pin_mux);  
        configure_module_pin_mux(mmc0_pin_mux);  
#if defined(CONFIG_NAND)  
        configure_module_pin_mux(nand_pin_mux);  
#elif defined(CONFIG_NOR)  
        configure_module_pin_mux(bone_norcape_pin_mux);  
#else  
        configure_module_pin_mux(mmc1_pin_mux);  
#endif  
    } else if (board_is_gp_evm(header)) {  
        /* General Purpose EVM */  
        unsigned short profile = detect_daughter_board_profile();  
        configure_module_pin_mux(rgmii1_pin_mux);  
        configure_module_pin_mux(mmc0_pin_mux);  
        /* In profile #2 i2c1 and spi0 conflict. */  
        if (profile & ~PROFILE_2)  
            configure_module_pin_mux(i2c1_pin_mux);  
        /* Profiles 2 & 3 don't have NAND */  
#ifdef CONFIG_NAND  
        if (profile & ~(PROFILE_2 | PROFILE_3))  
            configure_module_pin_mux(nand_pin_mux);  
#endif  
        else if (profile == PROFILE_2) {  
            configure_module_pin_mux(mmc1_pin_mux);  
            configure_module_pin_mux(spi0_pin_mux);  
        }  
    } else if (board_is_idk(header)) {  
        /* Industrial Motor Control (IDK) */  
        configure_module_pin_mux(mii1_pin_mux);  
        configure_module_pin_mux(mmc0_no_cd_pin_mux);  
    } else if (board_is_evm_sk(header)) {  
        /* Starter Kit EVM */  
        configure_module_pin_mux(i2c1_pin_mux);  
        configure_module_pin_mux(gpio0_7_pin_mux);  
        configure_module_pin_mux(rgmii1_pin_mux);  
        configure_module_pin_mux(mmc0_pin_mux_sk_evm);  
    } else if (board_is_bone_lt(header)) {  
        /* Beaglebone LT pinmux */  
        configure_module_pin_mux(i2c1_pin_mux);  
        configure_module_pin_mux(mii1_pin_mux);  
        configure_module_pin_mux(mmc0_pin_mux);  
#if defined(CONFIG_NAND)  
        configure_module_pin_mux(nand_pin_mux);  
#elif defined(CONFIG_NOR)  
        configure_module_pin_mux(bone_norcape_pin_mux);  
#else  
        configure_module_pin_mux(mmc1_pin_mux);  
#endif  
    } else {  
        puts("Unknown board, cannot configure pinmux.");  
        hang();  
    }  
} 

6、另外,这个版本的u-boot有个bug,需要修改fat_register_device(fs/fat/fat.c)函数:

int fat_register_device(block_dev_desc_t *dev_desc, int part_no)  
{  
    disk_partition_t info;  
  
    /* First close any currently found FAT filesystem */  
    cur_dev = NULL;  
  
    /* Read the partition table, if present */  
    if (get_partition_info(dev_desc, part_no, &info)) {  
        /*if (part_no != 0) { 
            printf("** Partition %d not valid on device %d **\n", 
                    part_no, dev_desc->dev); 
            return -1; 
        }*/  
  
        info.start = 0;  
        info.size = dev_desc->lba;  
        info.blksz = dev_desc->blksz;  
        info.name[0] = 0;  
        info.type[0] = 0;  
        info.bootable = 0;  
#ifdef CONFIG_PARTITION_UUIDS  
        info.uuid[0] = 0;  
#endif  
    }  
  
    return fat_set_blk_dev(dev_desc, &info);  
} 

7、至此,u-boot就已经可以启动了,但是有多余的步骤和log,不过可以去掉,现在uboot就可以编译了,交叉编译工具用的是TI提供的,编译方法如下:

 
make am335x_evm_defconfig 
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- 

本文摘自:http://blog.csdn.net/girlkoo/article/details/41183217 作者:girlkoo

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