FreeRTOS-Kernel/FreeRTOS/Demo/RISC-V-spike-htif_GCC

Emulating generic RISC-V 32bit machine on spike

Requirements

1. GNU RISC-V toolchains (tested on Crosstool-NG)
2. spike from https://github.com/riscv/riscv-isa-sim
3. OpenOCD from https://github.com/riscv/riscv-openocd

How to build toolchain

Clone the Crosstool-NG and configure Crosstool-NG.

$ git clone https://github.com/crosstool-ng/crosstool-ng
$ cd crosstool-ng
$ ./bootstrap
$ ./configure --enable-local
$ make

Generate toolchain configuration:

• For RV32 builds:

  Create a file name as "defconfig" ( should be exactly the same, no file extension ) with the below content:

  CT_EXPERIMENTAL=y
  CT_ARCH_RISCV=y
  CT_ARCH_64=n
  CT_ARCH_ARCH="rv32ima"
  CT_ARCH_ABI="ilp32"
  CT_TARGET_CFLAGS="-mcmodel=medany"
  CT_TARGET_LDFLAGS="-mcmodel=medany"
  CT_MULTILIB=y
  CT_DEBUG_GDB=y
  

• For RV64 builds: Create a file name as "defconfig" ( should be exactly the same, no file extension ) with the below content:

  CT_EXPERIMENTAL=y
  CT_ARCH_RISCV=y
  CT_ARCH_64=y
  CT_ARCH_ARCH="rv64ima"
  CT_ARCH_ABI="lp64"
  CT_TARGET_CFLAGS="-mcmodel=medany"
  CT_TARGET_LDFLAGS="-mcmodel=medany"
  CT_MULTILIB=y
  CT_DEBUG_GDB=y
  

Run the below command. The configurations will be save to .config file.:

./ct-ng defconfig

Build the GNU toolchain for RISC-V.

$ ./ct-ng build

A toolchain is installed at ~/x-tools/riscv32-unknown-elf or ~/x-tools/riscv64-unknown-elf directory depends on your build.

How to build

Add path of toolchain that is described above section.

$ export PATH=~/x-tools/{YOUR_TOOLCHAIN}/bin:$PATH

To build, simply run make. If you want a debug build, pass DEBUG=1. If you want an RV64 build, pass XLEN=64.

The resulting executable file is ./build/RTOSDemo32.axf or ./build/RTOSDemo64.axf.

How to run

RV32:

$ spike -p1 --isa RV32IMA -m0x80000000:0x10000000 --rbb-port 9824 \
        ./build/RTOSDemo32.axf

RV64:

$ spike -p1 --isa RV64IMA -m0x80000000:0x10000000 --rbb-port 9824 \
        ./build/RTOSDemo64.axf

How to debug with gdb

Start OpenOCD in one terminal:

$ openocd -f spike-1.cfg

Start gdb in another:

$ riscv64-unknown-elf-gdb ./build/RTOSDemo.axf
...
(gdb) target extended-remote localhost:3333
...
(gdb) info threads

(As of 3/22/2021 OpenOCD's RISC-V FreeRTOS awareness is still incomplete.)

Description

This demo starts separate transmit and receive threads. The transmit thread sends integers through a queue. Both threads print out what they're sending/receiving using HTIF.