mirror of
https://github.com/AsahiLinux/u-boot
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82 lines
3.6 KiB
Text
82 lines
3.6 KiB
Text
================================================================================
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Useful notes on bulding and using of U-Boot on ARC EM Development Kit (AKA EMDK)
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================================================================================
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BOARD OVERVIEW
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The DesignWare ARC EM Development Kit is FPGA-bases platform for rapid
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software development on the ARC EM family of processors.
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Since this board is based on FPGA it's possible to load and use different
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versions of ARC EM CPUs. U-Boot is built to be run on the simplest
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possible configuration which means the same one binary will work on more
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advanced configurations as well.
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The board has the following features useful for U-Boot:
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* On-board 2-channel FTDI TTL-to-USB converter
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- The first channel is used for serial debug port (which makes it possible
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to use a serial connection on pretty much any host machine be it
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Windows, Linux or Mac).
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On Linux machine typucally FTDI serial port would be /dev/ttyUSB0.
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There's no HW flow-control and baud-rate is 115200.
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- The second channel is used for built-in Digilent USB JTAG probe.
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That means no extra hardware is required to access ARC core from a
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debugger on development host. Both proprietary MetaWare debugger and
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open source OpenOCD + GDB client are supported.
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- Also with help of this FTDI chip it is possible to reset entire
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board with help of a special `rff-ftdi-reset` utility, see:
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https://github.com/foss-for-synopsys-dwc-arc-processors/rff-ftdi-reset
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* Micro SD-card slot
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- U-Boot expects to see the very first partition on the card formatted as
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FAT file-system and uses it for keeping its environment in `uboot.env`
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file. Note uboot.env is not just a text file but it is auto-generated
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file created by U-Boot on invocation of `saveenv` command.
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It contains a checksum which makes this saved environment invalid in
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case of maual modification.
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- There might be more useful files on that first FAT partition like
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user applications, data files etc.
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* 256 KiB of "ROM"
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- This so-called "ROM" is a part of FPGA image and even though it
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might be unlocked for writes its initial content will be restored
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on the next power-on.
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BUILDING U-BOOT
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1. Configure U-Boot:
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------------------------->8----------------------
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make emdk_defconfig
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------------------------->8----------------------
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2. To build Elf file (for example to be used with host debugger via JTAG
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connection to the target board):
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------------------------->8----------------------
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make mdbtrick
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------------------------->8----------------------
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This will produce `u-boot` Elf file.
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3. To build binary image to be put in "ROM":
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------------------------->8----------------------
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make u-boot.bin
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------------------------->8----------------------
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EXECUTING U-BOOT
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1. The EMDK board is supposed to auto-start U-Boot image stored in ROM on
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power-on. For that make sure VCCIO DIP-switches are all in "off" state.
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2. Though it is possible to load U-Boot as a simple Elf file via JTAG right
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in "ROM" and start it from the debugger. One important note here we first
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need to enable writes into "ROM" by writing 1 to 0xf0001000.
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2.1. In case of proprietary MetaWare debugger run:
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------------------------->8----------------------
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mdb -dll=opxdarc.so -OK -preloadexec="eval *(int*)0xf0001000=0" u-boot
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------------------------->8----------------------
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