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Historically, the reset_cpu() function had an `addr` parameter which was meant to pass in an address of the reset vector location, where the CPU should reset to. This feature is no longer used anywhere in U-Boot as all reset_cpu() implementations now ignore the passed value. Generic code has been added which always calls reset_cpu() with `0` which means this feature can no longer be used easily anyway. Over time, many implementations seem to have "misunderstood" the existence of this parameter as a way to customize/parameterize the reset (e.g. COLD vs WARM resets). As this is not properly supported, the code will almost always not do what it is intended to (because all call-sites just call reset_cpu() with 0). To avoid confusion and to clean up the codebase from unused left-overs of the past, remove the `addr` parameter entirely. Code which intends to support different kinds of resets should be rewritten as a sysreset driver instead. This transformation was done with the following coccinelle patch: @@ expression argvalue; @@ - reset_cpu(argvalue) + reset_cpu() @@ identifier argname; type argtype; @@ - reset_cpu(argtype argname) + reset_cpu(void) { ... } Signed-off-by: Harald Seiler <hws@denx.de> Reviewed-by: Simon Glass <sjg@chromium.org> |
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config.mk | ||
emsdp.c | ||
Kconfig | ||
MAINTAINERS | ||
Makefile | ||
README |
================================================================================ Useful notes on bulding and using of U-Boot on ARC EM Software Development Platform (AKA EMSDP) ================================================================================ BOARD OVERVIEW The DesignWare ARC EM Software Development Platform is FPGA-bases platform for rapid software development on the ARC EM family of processors. Since this board is based on FPGA it's possible to load and use different versions of ARC EM CPUs. U-Boot is built to be run on the simplest possible configuration which means the same one binary will work on more advanced configurations as well. The board has the following features useful for U-Boot: * On-board 2-channel FTDI TTL-to-USB converter - The first channel is used for serial debug port (which makes it possible to use a serial connection on pretty much any host machine be it Windows, Linux or Mac). On Linux machine typucally FTDI serial port would be /dev/ttyUSB0. There's no HW flow-control and baud-rate is 115200. - The second channel is used for built-in Digilent USB JTAG probe. That means no extra hardware is required to access ARC core from a debugger on development host. Both proprietary MetaWare debugger and open source OpenOCD + GDB client are supported. - Also with help of this FTDI chip it is possible to reset entire board with help of a special `rff-ftdi-reset` utility, see: https://github.com/foss-for-synopsys-dwc-arc-processors/rff-ftdi-reset * Micro SD-card slot - U-Boot expects to see the very first partition on the card formatted as FAT file-system and uses it for keeping its environment in `uboot.env` file. Note uboot.env is not just a text file but it is auto-generated file created by U-Boot on invocation of `saveenv` command. It contains a checksum which makes this saved environment invalid in case of maual modification. - There might be more useful files on that first FAT partition like user applications, data files etc. * 256 KiB of "ROM" - This so-called "ROM" is a part of FPGA image and even though it might be unlocked for writes its initial content will be restored on the next power-on. BUILDING U-BOOT 1. Configure U-Boot: ------------------------->8---------------------- make emsdp_defconfig ------------------------->8---------------------- 2. To build Elf file (for example to be used with host debugger via JTAG connection to the target board): ------------------------->8---------------------- make mdbtrick ------------------------->8---------------------- This will produce `u-boot` Elf file. 3. To build binary image to be put in "ROM": ------------------------->8---------------------- make u-boot.bin ------------------------->8---------------------- EXECUTING U-BOOT 1. The EMSDP board is supposed to auto-start U-Boot image stored in ROM on power-on. For that make sure VCCIO DIP-switches are all in "off" state. 2. Though it is possible to load U-Boot as a simple Elf file via JTAG right in "ROM" and start it from the debugger. One important note here we first need to enable writes into "ROM" by writing 1 to 0xf0001000. 2.1. In case of proprietary MetaWare debugger run: ------------------------->8---------------------- mdb -digilent -OK -preloadexec="eval *(int*)0xf0001000=0" u-boot ------------------------->8----------------------