How to build bare metal applications on HiFive1-Board

This Repository contains some software examples for use with the HiFive1-Board of SiFive and our binary-compatible Riscv-VP (repo). Here, an old version of the freedom-e-sdk of SiFive is pinned and used for building/uploading programs.

The main idea of this repo is to build small and easy bare metal programs to be used in conjunction with the vp-breadboard which is a breadboard/pcb simulator with some buttons, oled display and leds. It is to be found in the virtual-breadboard repo and can be opened before calling any of the make sim-* targets.

1. Prerequisites on ubuntu (see needed packages at https://github.com/sifive/freedom-e-sdk/tree/baeeb8f):

   sudo apt-get install autoconf automake libmpc-dev libmpfr-dev libgmp-dev gawk bison flex texinfo libtool libusb-1.0-0-dev make g++ pkg-config libexpat1-dev zlib1g-dev

2. Clone and update the sifive--hifive1 repository:

   git clone https://github.com/agra-uni-bremen/sifive-hifive1
   cd sifive-hifive1/freedom-e-sdk
   git submodule update --init # may take a bit

3. Either:

   a) If you would like to avoid compiling the tools from source, they are available as pre-built binaries from https://www.sifive.com/products/tools

   For OpenOCD and/or RISC-V GNU Toolchain, download the .tar.gz for your platform, and unpack it to your desired location. Then, use the RISCV_PATH and RISCV_OPENOCD_PATH variables when attempting to use the tools:

   cp openocd-<date>-<platform>.tar.gz /my/desired/location/
   cp riscv64-unknown-elf-gcc-<date>-<platform>.tar.gz /my/desired/location
   cd /my/desired/location
   tar -xvf openocd-<date>-<platform>.tar.gz
   tar -xvf riscv64-unknown-elf-gcc-<date>-<platform>.tar.gz
   export RISCV_OPENOCD_PATH=/my/desired/location/openocd
   export RISCV_PATH=/my/desired/location/riscv64-unknown-elf-gcc-<date>-<version>
   

   b) Or build the toolchain directly. This may or may not work with the old pin of the toolchain. If the following does not work, please refer to https://github.com/sifive/freedom-tools.

   cd freedom-e-sdk
   git submodule update --init --recursive # may take a bit
   make riscv-gnu-toolchain -j$(nproc) # may also take a bit

   Build openocd (if you want to load a program on the real board) in sifive--hifive1/freedom-e-sdk/: make openocd # need only to be done once

4. Build and upload a program to the board:

   make upload-snake

   Optional: If you have the hifive-vp from the riscv-vp repository in your $PATH, you may also start the simulation by typing

   make sim-snake

5. Show program output:

   screen /dev/ttyUSB1 115200

In case screen does not work use (this may happen when running screen a second time):

`cat /dev/ttyUSB1	# NOTE: need to run screen once before this command works`

Press the reset button on the board to restart (and thus see output). NOTE: /dev/ttyUSB0 is the debug interface.

ZEPHYR OS

To use Zephyr, see zephyr/RREADME.rst. (Install OS Packages, pip packages) To build for HiFive1, use example zephyrrc file, modify for your paths, rename to ~/.zephyrrc and source it(?). Source zephyr-env.sh. Then build your project:

mkdir build && cmake .. -DBOARD=$BOARD
make -j6

Uploading Zephyr-Elfs to board

Basically the same procedure as freedom-e-sdk, but manual.

$ ${SDK_PATH}/work/build/openocd/prefix/bin/openocd -f ${SDK_PATH}/bsp/env/freedom-e300-hifive1/openocd.cfg &
$ riscv32-unknown-elf-gdb
 set remotetimeout 240
 target extended-remote localhost:3333
 monitor reset halt
 monitor flash protect 0 64 last off
 load zephyr/zephyr.elf
 monitor resume

Other Doc

FreeRTOS example uses 14.7kiB out of 16kiB RAM (with 2k stack):

size RISCV_HiFive1_GCC.elf -d
   text	   data	    bss	    dec	    hex	filename
  17079	   1076	  13953	  32108	   7d6c	RISCV_HiFive1_GCC.elf

Zephyr uses with the philosophers demo:

Memory region         Used Size  Region Size  %age Used
	         ROM:       22960 B        12 MB      0.18%
	         RAM:        9440 B        16 KB     57.62%
	    IDT_LIST:         553 B         2 KB     27.00%

Acknowledgements:

This work was supported in part by the German Federal Ministry of Education and Research (BMBF) within the project SATiSFy under contract no. 16KIS0821K.