Hart Software Services

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.

Contributions

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

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)

Building

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.

Building on Linux

Clone from https://github.com/pic64gx/pic64gx-hart-software-services.git and then

$ cp boards/pic64gx-curiosity-kit/def_config .config
$ make config
$ make

Building on Windows

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

Programming

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

Debug

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.

Scrubbing for ECCs and Non-Coherent Memory.

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.

CONFIG_SERVICE_SCRUB is not set

pic64gx / pic64gx-hart-software-services

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