[beagleboard] U-boot image w/magic number bypass?

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1

Can read the eeprom content once and hardcode into u-boot?

2

yes, pretty easy :

edit board/ti/am335x/evm.c

void spl_board_init(void)
{
	uchar pmic_status_reg;

	/* init board_id, configure muxes */
	board_init();
	if(1){ // assum we use bone 
	// if (!strncmp("A335BONE", [header.name](http://header.name), 8)) {
		/* BeagleBone PMIC Code */
		if (i2c_probe(TPS65217_CHIP_PM))
			return;

		if (tps65217_reg_read(STATUS, &pmic_status_reg))
			return;

		/* Increase USB current limit to 1300mA */
		if (tps65217_reg_write(PROT_LEVEL_NONE, POWER_PATH,
				       USB_INPUT_CUR_LIMIT_1300MA,
				       USB_INPUT_CUR_LIMIT_MASK))
			printf("tps65217_reg_write failure\n");

		/* Only perform PMIC configurations if board rev > A1 */
		if (!strncmp(header.version, "00A1", 4))
			return;

		/* Set DCDC2 (MPU) voltage to 1.275V */
		if (tps65217_voltage_update(DEFDCDC2,
					     DCDC_VOLT_SEL_1275MV)) {
			printf("tps65217_voltage_update failure\n");
			return;
		}

		/* Set LDO3, LDO4 output voltage to 3.3V */
		if (tps65217_reg_write(PROT_LEVEL_2, DEFLS1,
				       LDO_VOLTAGE_OUT_3_3, LDO_MASK))
			printf("tps65217_reg_write failure\n");

		if (tps65217_reg_write(PROT_LEVEL_2, DEFLS2,
				       LDO_VOLTAGE_OUT_3_3, LDO_MASK))
			printf("tps65217_reg_write failure\n");

		if (!(pmic_status_reg & PWR_SRC_AC_BITMASK)) {
			printf("No AC power, disabling frequency switch\n");
			return;
		}

		/* Set MPU Frequency to 720MHz */
		mpu_pll_config(MPUPLL_M_720);



...
3

yes, pretty easy :

edit board/ti/am335x/evm.c

void spl_board_init(void)
{
	uchar pmic_status_reg;

	/* init board_id, configure muxes */
	board_init();
	if(1){ // assum we use bone 
	// if (!strncmp("A335BONE", [header.name](http://header.name), 8)) {
		/* BeagleBone PMIC Code */
		if (i2c_probe(TPS65217_CHIP_PM))
			return;

		if (tps65217_reg_read(STATUS, &pmic_status_reg))
			return;

		/* Increase USB current limit to 1300mA */
		if (tps65217_reg_write(PROT_LEVEL_NONE, POWER_PATH,
				       USB_INPUT_CUR_LIMIT_1300MA,
				       USB_INPUT_CUR_LIMIT_MASK))
			printf("tps65217_reg_write failure\n");

		/* Only perform PMIC configurations if board rev > A1 */
		if (!strncmp(header.version, "00A1", 4))
			return;

		/* Set DCDC2 (MPU) voltage to 1.275V */
		if (tps65217_voltage_update(DEFDCDC2,
					     DCDC_VOLT_SEL_1275MV)) {
			printf("tps65217_voltage_update failure\n");
			return;
		}

		/* Set LDO3, LDO4 output voltage to 3.3V */
		if (tps65217_reg_write(PROT_LEVEL_2, DEFLS1,
				       LDO_VOLTAGE_OUT_3_3, LDO_MASK))
			printf("tps65217_reg_write failure\n");

		if (tps65217_reg_write(PROT_LEVEL_2, DEFLS2,
				       LDO_VOLTAGE_OUT_3_3, LDO_MASK))
			printf("tps65217_reg_write failure\n");

		if (!(pmic_status_reg & PWR_SRC_AC_BITMASK)) {
			printf("No AC power, disabling frequency switch\n");
			return;
		}

		/* Set MPU Frequency to 720MHz */
		mpu_pll_config(MPUPLL_M_720);

This will not do. A lot of the code (and even a bit more when you start talking Black) depend on the EEPROM contents to see which of the 4 boards and their variations we’re on. If you MUST go this way, what you want to do is make read_eeprom populate the in-memory copy of the EEPROM data as pretending to be the board you almost have.

4

Please tell the eeprom address for reading on bbb