AM335x(TQ335x)學習筆記——u-boot-2014.10移植
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由于TI的am335x evm開發使用了一個eeprom保存了板載配置信息，用來區分不同板子的型號的，而TQ335x沒有這個eeprom，因此，需要修改eeprom相關的部分，使u-boot適應TQ335x開發板。
本文引用地址：http://www.104case.com/article/201611/322817.htm使用source insight查看代碼，很容易發現，所有獲取板載配置的部分都是通過讀取eeprom獲得的，因此，首選修改read_eeprom（board/ti/am335x/board.c）函數，具體的修改如下：
- staticintread_eeprom(structam335x_baseboard_id*header)
- {
- #if1
- strcpy(header->name,"TQ335x");
- #else
- /*Checkifbaseboardeepromisavailable*/
- if(i2c_probe(CONFIG_SYS_I2C_EEPROM_ADDR)){
- puts("CouldnotprobetheEEPROM;somethingfundamentally"
- "wrongontheI2Cbus.");
- return-ENODEV;
- }
- /*readtheeepromusingi2c*/
- if(i2c_read(CONFIG_SYS_I2C_EEPROM_ADDR,0,2,(uchar*)header,
- sizeof(structam335x_baseboard_id))){
- puts("CouldnotreadtheEEPROM;somethingfundamentally"
- "wrongontheI2Cbus.");
- return-EIO;
- }
- if(header->magic!=0xEE3355AA){
- /*
- *readtheeepromusingi2cagain,
- *butuseonlya1byteaddress
- */
- if(i2c_read(CONFIG_SYS_I2C_EEPROM_ADDR,0,1,(uchar*)header,
- sizeof(structam335x_baseboard_id))){
- puts("CouldnotreadtheEEPROM;something"
- "fundamentallywrongontheI2Cbus.");
- return-EIO;
- }
- if(header->magic!=0xEE3355AA){
- printf("Incorrectmagicnumber(0x%x)inEEPROM",
- header->magic);
- return-EINVAL;
- }
- }
- #endif
- return0;
- }
然后是修改get_dpll_ddr_params（board/ti/am335x/board.c）函數，具體的修改內容如下：
- conststructdpll_params*get_dpll_ddr_params(void)
- {
- structam335x_baseboard_idheader;
- enable_i2c0_pin_mux();
- i2c_init(CONFIG_SYS_OMAP24_I2C_SPEED,CONFIG_SYS_OMAP24_I2C_SLAVE);
- if(read_eeprom(&header)<0)
- puts("CouldnotgetboardID.");
- if(board_is_tq335x(&header)||board_is_evm_sk(&header))
- return&dpll_ddr_evm_sk;
- elseif(board_is_bone_lt(&header))
- return&dpll_ddr_bone_black;
- elseif(board_is_evm_15_or_later(&header))
- return&dpll_ddr_evm_sk;
- else
- return&dpll_ddr;
- }
- voidsdram_init(void)
- {
- __maybe_unusedstructam335x_baseboard_idheader;
- if(read_eeprom(&header)<0)
- puts("CouldnotgetboardID.");
- if(board_is_evm_sk(&header)){
- /*
- *EVMSK1.2Aandlaterusegpio0_7toenableDDR3.
- *Thisissafeenoughtodoonolderrevs.
- */
- 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);
- elseif(board_is_bone_lt(&header))
- config_ddr(400,&ioregs_bonelt,
- &ddr3_beagleblack_data,
- &ddr3_beagleblack_cmd_ctrl_data,
- &ddr3_beagleblack_emif_reg_data,0);
- elseif(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);
- }
關鍵詞：
AM335xTQ335xu-boo
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