1================================================================================ 2Useful notes on bulding and using of U-Boot on 3ARC EM Software Development Platform (AKA EMSDP) 4================================================================================ 5 6 BOARD OVERVIEW 7 8 The DesignWare ARC EM Software Development Platform is FPGA-bases platform 9 for rapid software development on the ARC EM family of processors. 10 11 Since this board is based on FPGA it's possible to load and use different 12 versions of ARC EM CPUs. U-Boot is built to be run on the simplest 13 possible configuration which means the same one binary will work on more 14 advanced configurations as well. 15 16 The board has the following features useful for U-Boot: 17 * On-board 2-channel FTDI TTL-to-USB converter 18 - The first channel is used for serial debug port (which makes it possible 19 to use a serial connection on pretty much any host machine be it 20 Windows, Linux or Mac). 21 On Linux machine typucally FTDI serial port would be /dev/ttyUSB0. 22 There's no HW flow-control and baud-rate is 115200. 23 24 - The second channel is used for built-in Digilent USB JTAG probe. 25 That means no extra hardware is required to access ARC core from a 26 debugger on development host. Both proprietary MetaWare debugger and 27 open source OpenOCD + GDB client are supported. 28 29 - Also with help of this FTDI chip it is possible to reset entire 30 board with help of a special `rff-ftdi-reset` utility, see: 31 https://github.com/foss-for-synopsys-dwc-arc-processors/rff-ftdi-reset 32 33 * Micro SD-card slot 34 - U-Boot expects to see the very first partition on the card formatted as 35 FAT file-system and uses it for keeping its environment in `uboot.env` 36 file. Note uboot.env is not just a text file but it is auto-generated 37 file created by U-Boot on invocation of `saveenv` command. 38 It contains a checksum which makes this saved environment invalid in 39 case of maual modification. 40 41 - There might be more useful files on that first FAT partition like 42 user applications, data files etc. 43 44 * 256 KiB of "ROM" 45 - This so-called "ROM" is a part of FPGA image and even though it 46 might be unlocked for writes its initial content will be restored 47 on the next power-on. 48 49 50 BUILDING U-BOOT 51 52 1. Configure U-Boot: 53 ------------------------->8---------------------- 54 make emsdp_defconfig 55 ------------------------->8---------------------- 56 57 2. To build Elf file (for example to be used with host debugger via JTAG 58 connection to the target board): 59 ------------------------->8---------------------- 60 make mdbtrick 61 ------------------------->8---------------------- 62 63 This will produce `u-boot` Elf file. 64 65 3. To build binary image to be put in "ROM": 66 ------------------------->8---------------------- 67 make u-boot.bin 68 ------------------------->8---------------------- 69 70 71 EXECUTING U-BOOT 72 73 1. The EMSDP board is supposed to auto-start U-Boot image stored in ROM on 74 power-on. For that make sure VCCIO DIP-switches are all in "off" state. 75 76 2. Though it is possible to load U-Boot as a simple Elf file via JTAG right 77 in "ROM" and start it from the debugger. One important note here we first 78 need to enable writes into "ROM" by writing 1 to 0xf0001000. 79 80 2.1. In case of proprietary MetaWare debugger run: 81 ------------------------->8---------------------- 82 mdb -dll=opxdarc.so -OK -preloadexec="eval *(int*)0xf0001000=0" u-boot 83 ------------------------->8---------------------- 84