This BSP is a coprocessor in the cv18xx series processor, using RISCV C906 @ 700Mhz.
Features:
- No MMU
- Integrated Floating-point Unit (FPU)
## Toolchain Download
Download the toolchain for `riscv64-unknown-elf-gcc`: [https://occ-oss-prod.oss-cn-hangzhou.aliyuncs.com/resource//1705395512373/Xuantie-900-gcc-elf-newlib-x86_64-V2.8.1-20240115.tar.gz](https://occ-oss-prod.oss-cn-hangzhou.aliyuncs.com/resource//1705395512373/Xuantie-900-gcc-elf-newlib-x86_64-V2.8.1-20240115.tar.gz)
> Note:
Current BSP only supports Linux compilation.
After correct decompression, add the local path of the `riscv64-unknown-elf-gcc` toolchain to `EXEC_PATH` in `rtconfig.py`, or specify the path through the `RTT_EXEC_PATH` environment variable.
It will automatically download env related scripts to the ~/.env directory, then execute
```shell
$ source ~/.env/env.sh
$ pkgs --update
```
After updating the software packages, execute `scons -j10` or `scons -j10 --verbose` to compile this BSP. Or use the `scons --exec-path="GCC toolchain path"` command to compile directly while specifying the toolchain location. If the compilation is correct, the rtthread.elf file will be generated.
After the compilation is completed, the script automatically calls the `combine-fip.sh` script for packaging, and generates `fip.sd`, which is the c906_little file for SD card startup.
The first time the `combine-fip.sh` script is called, it will automatically download the required `opsbsbi`, `fsbl`, `uboot`, and other related files to the `bsp/cvitek/cvitek_bootloader` directory, please be patient.
After downloading, it will automatically decompress and compile. Subsequently, when compiling the same type of development board again, only the relevant files will be called to package and synthesize `fip.bin`. If you need to manually compile the related `cvitek_bootloader` files, you can execute `bash build.sh lunch` in the `bsp/cvitek/cvitek_bootloader` directory to choose the corresponding development board for compilation.
## Running
1. Divide the SD card into 2 partitions, the 1st partition is used to store bin files, and the 2nd partition is used as a data storage partition, with the partition format being `FAT32`.
2. Copy the `fip.bin` and `boot.sd` from the root directory into the 1st partition of the SD card. Subsequent firmware updates only require copying the `fip.sd` file.
Where:
- fip.bin: fsbl, opensbi, uboot, c906_little packaged bin file
- boot.sd: bin file packaged by the main kernel
After updating `fip.sd`, restarting will show the output information on the serial port:
