This is the Hart Software Services (HSS) code.
On PIC64GX, this is comprised of two portions:
-
A superloop monitor running on the E51 minion processor, which receives requests from the individual U54 application processors to perform certain services on their behalf;
-
A Machine-Mode software interrupt trap handler, which allows the E51 to send messages to the U54s, and request them to perform certain functions for it related to rebooting a U54.
The HSS performs boot and system monitoring functions for PIC64GX.
The HSS is compressed (DEFLATE) and stored in eNVM. On power-up, a small decompressor decompressor wrapper inflates the HSS from eNVM flash to L2-Scratchpad memory and starts the HSS.
Pull requests to this repository must include a per-commit sign-off made by a contributor stating that they agree to the terms published at https://developercertificate.org/ for that particular contribution.
Source code is found under the hart-software-services folder.
hart-software-services
├── application (main function, crt startup, init function)
├── baremetal
│ ├── drivers (local modules)
│ └── pic64gx-bare-metal-library (subtree)
├── boards
│ └── pic64gx-curiosity-kit
├── envm-wrapper (helper routines to inflate the HSS to L2-Scratchpad)
├── include
├── init (system initialization)
├── modules
│ ├── compression
│ ├── crypto
│ ├── debug (helper routines for function profiling)
│ ├── misc (miscellaneous routines)
│ └── ssmb (secure software message bus)
│ └── ipi
├── services (software service state machines)
│ ├── beu
│ ├── boot
│ ├── crypto
│ ├── ddr
│ ├── goto
│ ├── ipi_poll
│ ├── mmc
│ ├── opensbi
│ ├── powermode
│ ├── qspi
│ ├── scrub
│ ├── sgdma
│ ├── spi
│ ├── tinycli
│ ├── uart
│ ├── usbdmsc
│ │ └── flash_drive
│ ├── wdog
│ └── ymodem
└── thirdparty
├── Kconfiglib (a Kconfig implementation in Python)
├── libecc (library for elliptic curves based cryptography (ECC))
├── miniz (fast lossless compression library)
└── opensbi (RISC-V OpenSBI)
The build is configured using the Kconfig system of selecting build options.
The Hart Software Services includes the Kconfig parsing infrastructure directly as a third-party tool invoked by the build system.
Both Linux and Windows are supported by Kconfiglib.
The HSS currently support PIC64GX-based Curiosity kit (pic64gx-curiosity-kit) as a board build target.
Before building, download and install the xPack GNU RISC-V Embedded GCC package from https://github.com/xpack-dev-tools/riscv-none-elf-gcc-xpack/releases/tag/v13.2.0-2 for your platform, unarchive it and add the appropriate path to xpack-riscv-none-elf-gcc-13.2.0-2/bin/ to your path environment variable.
Clone from https://github.com/pic64gx/pic64gx-hart-software-services.git and then
$ cp boards/pic64gx-curiosity-kit/def_config .config
$ make config
$ make
Clone from https://github.com/pic64gx/pic64gx-hart-software-services.git and then
C:\pic64gx-hart-software-services\> copy boards\pic64gx-curiosity-kit\def_config .config
C:\pic64gx-hart-software-services\> make config
C:\pic64gx-hart-software-services\> make
Download and untar the PIC64GX OpenOCD release from https://github.com/microchip-fpga/openocd/releases/tag/v0.12.0-mchp.0.0.1
$ cd xpack-openocd-0.12.0-3
$ ./bin/openocd --command "set DEVICE pic64gx" -f board/microchip_riscv_efp5.cfg
In a separate terminal, connect to the board from gdb target remote :3333 monitor reset halt load /path/to/hss-envm-wrapper.elf
The modules/debug/ subdirectory contains code to enable a number of debug features, including:
- Logging all state machine transitions to the serial console (MMUART0);
- Periodic logging of super loop timings to the serial console;
- Logging of IPI statistics to the serial console;
- Logging all IPI messages for MSC traces;
- Function profiling.
The HSS includes a scrubbing service (running on the E51) to scrub ECC protected memories such as DDR, L2 Scratchpad, LIM for correctable single-bit errors in an effort to correct them before they propagate to uncorrectable double-bit errors. Note that by default, mpfs-linux is configured such that DDR accesses to/from peripherals such as PCIe, eNVM and USB are directed to uncached memory addresses; with cache synchronisation performed explicitly by the Linux kerne. Enabling scrubbing can result in interfering with this default mpfs-linux behavior, and so it is important to configure mpfs-linux to only used coherent memory when using scrubbing.
As a consequence, scrubbing is currently off by default in provided def_config files.