Hi everyone, Embedded systems traditionally have several options when it comes to flash programming such as external JTAG devices, boot loader and/or operating system functionality. In case the flash is empty, on R-Car Gen3 there are two choices for flash programming: JTAG or using MD pins to select on-chip ROM boot instead of external storage. Out of several different boot modes available the SCIF D/L mode allows for software upload via an UART interface. Traditionally binary images provided by Renesas have been used together with the SCIF D/L mode. For such binaries the user was often requested to perform various board specific operations such as adjusting DIP switches and input addresses via the UART interface. Source code and documentation for "flash_writer" has been released at https://github.com/renesas-rcar/flash_writer/ Once the on-board storage has been initially programmed other software may be used for additional flash programming. Not utilizing SCIF D/L mode but also making use of flash_writer functionality is the abloader tool. Two software copies are stored in flash and may be switched between. It is available at https://github.com/marex/abloader The subject of this email "R-Car Gen3 Network Based Flash Programming Tool for SCIF D/L Mode" describes what in practice is just a chain-loaded U-Boot with networking support. But to get there several components are made use of: - Failsafe ROM-based SCIF D/L mode - Chain loading by U-Boot SPL - Hardware setup using ATF BL2 with RCAR_RPC_HYPERFLASH_LOCKED=0 - Networked flash programming via U-Boot DFU TFTP functionality The target platform in this case happens to be R-Car H3 ES2 Salvator-XS but the instructions should be generic enough as long as U-Boot support exists for the target and SCIF D/L mode can be enabled. - - - Step 1: Compiling the Flash Programming Tool Required software components are ATF and U-Boot. Step 1A: ATF For ATF the following git repository and commit have been used: https://github.com/ARM-software/arm-trusted-firmware/commit/8078b5c5a The ATF source code needs to be patched for SCIF D/L chain loading to work: https://github.com/marex/arm-trusted-firmware/commit/ced85c01d886cc39f51cc9dd3bae72e7061886a7 Generic build instructions for R-Car Gen3 ATF are available at: https://elinux.org/R-Car/Boards/ATF-Gen3 This includes information about how to setup MBEDTLS_DIR. For SCIF D/L chain loading some customization is needed: - Let U-Boot access the RPC HF via RCAR_RPC_HYPERFLASH_LOCKED=0 - No need for OPTEE so set SPD=none The exact commands used to build the ATF source code are: $ CROSS_COMPILE=_ make PLAT=rcar LSI=H3 MACHINE=salvator-x DCAR_DRAM_SPLIT=1 RCAR_DRAM_LPDDR4_MEMCONF=0 SPD=none RCAR_RPC_HYPERFLASH_LOCKED=0 MBEDTLS_DIR bl2 $ cp build/rcar/release/bl2.bin bl2-scif.bin Step 1B: U-Boot For U-Boot the v2021.10-rc4 was selected since it is the latest release: https://source.denx.de/u-boot/u-boot/-/tags/v2021.10-rc4 For flash programming to work on this particular target platform the DTS source for the board needs to be modified. For this board the following rpc node needs to be enabled: arch/arm/dts/r8a77950--salvator-x-u-boot.dts Instructions related to U-Boot on R-Car Gen3 (see "U-Boot recovery SPL") are available at: https://elinux.org/R-Car/Boards/U-Boot-Gen3 For SCIF D/L case build the source code and compress the binary using: $ make CROSS_COMPILE=_ rcar3_salvator-x_defconfig $ make CROSS_COMPILE=_ $ cp spl/u-boot-spl.scif . $ cp u-boot.bin u-boot-scif.bin $ cat u-boot-scif.bin | gzip -9 - > u-boot-scif.bin.gz Create chain loading images using: $ ./tools/mkimage -A arm -O arm-trusted-firmware -T firmware -C none -a 0xe6304000 -e 0xe6304000 -n "BL2" -d bl2-scif.bin bl2-scif.uimage $ ./tools/mkimage -A arm -O u-boot -T firmware -C gzip -a 0x50000000 -e 0x50000000 -n "U-Boot" -d u-boot-scif.bin.gz u-boot-scif.gz.img The following files are needed for next step: u-boot-spl.scif bl2-scif.uimage u-boot-scif.gz.img - - - Step 2: Using the Flash Programming Tool Network transfer of software images for flash programming allows for fast operation however the SCIF D/L boot with 3-step chain loading takes some time and effort to get right. Step 2A: Booting U-Boot from SCIF D/L mode Adjust the MD pins to enable SCIF D/L mode and configure your terminal program to 115200n81. Verify that a message is printed on the serial port after power on. Once the "please send !" message appears start ASCII upload of "u-boot-spl.scif". After a short while "U-Boot SPL, Trying to boot from UART" will appear. Then it is time to upload "bl2-scif.uimage" using ZMODEM/YMODEM/XMODEM protocol. After a while plenty of BL2 messages appear followed by yet another "U-Boot SPL, Trying to boot from UART". At such time proceed with upload of "u-boot-scif.gz.img". Once finished the regular U-Boot user interface will be available for console I/O. Step 2B: U-Boot Flash Programming Example Once the U-Boot user interface is presented a wide range of commands are available. To update the flash with a multi-component fitImage the following commands may be used: => setenv loadaddr 0x60000000 => setenv bootfile update.itb => bootp => dfu tftp 0x60000000 The above 4 steps may be used to quickly update all components of the on-board software stack. It however assumes that the file update.itb is formatted as expected and the network environment is correctly setup with services such as BOOTP/DHCP and TFTP.
