K3-bootswitch tool ================== This tool allows to boot the board in any boot mode from command line. This is useful for controlling the board remotely for individual developers as well as test farm. Hardware setup -------------- * USB cable should be connected from the board to the Linux PC * UART cable should be connected from the main_uart to Linux PC * Default switch settings should be for DFU boot mode * Power supply to the board should be connected via phidget USB relay Switch settings for DFU boot mode --------------------------------- * j721e-evm settings => SW8 = 1000 0000 SW9 = 0010 0000 SW3 = 0101 00 1010 * am65xx-evm settings => SW2 = 0001 0000 00 SW3 = 0000 0000 00 SW4 = 11 Usage ----- * Install dfu-util package on the Linux PC with ``sudo apt-get install dfu-util`` * To boot the j721e-evm board in MMC bootmode, run following ``sudo ./dfu-util.sh --j721e-evm --bootmode mmc`` Currently supported bootmodes are: **mmc, emmc, ospi, uart, noboot** * To mount the emmc from j721e-evm board to the Linux PC, run following ``sudo ./dfu-util.sh --j721e-evm --mount 0`` * To mount the SD card from am65xx-evm board to the Linux PC, run following ``sudo ./dfu-util.sh --am65xx-evm --mount 1`` Advantages ---------- * Allows to remotely control the board by eliminating need to physically change the switch settings * Can be used for regular development flow, where it removes the need to physically plug out the SD card for updating images. * Makes it very easy to partition, format and update contents of the eMMC device. * Can be used for factory flashing of the OSPI/eMMC images using automated scripts How it works ------------ The DFU bootmode allows to pass any custom bootloader to the board. By keeping the switch settings in DFU mode, board always waits for the Linux PC to send a bootloader. In Keystone3 SoC, the BOOTMODE and MCU_BOOTMODE registers reflect the values of the boot switches at the cold boot. This register can be modified and the values written are retained through the warm reset. These two features allows to set the bootmode from the command line PC tool. In the **boot_select** directory of this tool, there are many files which act as the custom bootloader every time the board boots with DFU-boot mode. The custom bootloader does only two important things; First it overwrites the BOOTMODE and MCU_BOOTMODE registers to change to the desired boot mode and then it issues a soft reset to the SoC causing it to boot the second time with new bootmode. All of this happens very fast when run from a script that it does not add considerable amount of time for developer bootflow. The mount of SD card or eMMC is achieved using the u-boot's UMS (USB Mass Storage) feature. In this case, the tool sends a real R5 u-boot as bootloader, System firmware ITB, A72 u-boot images and then runs the ums command. Note that all the binaries are being sent from the Linux PC, so there is absolutely no dependency on the contents of SD card. Customization ------------- Default setup assumes most common setup for Keystone3 EVM. In case you are using differnent mechanism, update the **dfu-boot.sh** script with following: * Update the **uart_dev** variable to reflect the correct tty device for main uart. (The one where all u-boot/SBL/kernel logs appear) * Update the **switch** variable to reflect the correct switch number which controls the power via phidget * If you have a differen mechanism to power the board, write your own implementation for **toggle_power** function instead of the default phidget commands Limitatinos ----------- * Do not use this mechanism to measure any boot time numbers * The bootloader images are specific to TI EVMs. Different images are required to be able to mount the SD/eMMC from custom boards * The u-boot will try to import the environment from eMMC. If that is broken, it will cause issues in mounting the devices using UMS