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Diffstat (limited to 'README.md')
| -rw-r--r-- | README.md | 196 |
1 files changed, 62 insertions, 134 deletions
@@ -1,15 +1,15 @@ <!-- README.md - Description of sbc-harness - Copyright (C) 2024 Luke T. Shumaker <lukeshu@lukeshu.com> + Copyright (C) 2024-2025 Luke T. Shumaker <lukeshu@lukeshu.com> SPDX-License-Identifier: AGPL-3.0-or-later --> # Building -Building requires cmake, make, an "arm-none-eabi" toolchain (including -newlib), and picotool (including the .cmake files; -eg. /usr/lib/cmake/picotool/*.cmake). +Building requires CMake, GNU Make, an "arm-none-eabi" toolchain +(including newlib), and picotool (including the `.cmake` files; +e.g. `/usr/lib/cmake/picotool/*.cmake`). At the time of this writing, on Parabola GNU/Linux-libre that means: @@ -18,140 +18,68 @@ At the time of this writing, on Parabola GNU/Linux-libre that means: - arm-none-eabi-binutils 2.42-1 - arm-none-eabi-gcc 14.1.0-1 - arm-none-eabi-newlib 4.4.0.20231231-1 - - picotool 2.0.0-2 - -```bash -mkdir build -cd build -cmake -DCMAKE_BUILD_TYPE=Debug .. -make -``` -# Debugging - -UART: -- pin1: gpio0: TX (so connect it to your FTDI's RX) -- pin2: gpio1: RX (so connect it to your FTDI's TX) -- pin3: gnd (so connect it to your FTDI's GND) -- `picocom --baud=115200 /dev/ttyUSB0` -- `picocom --baud=115200 /dev/ttyACM0` - -- `openocd -f interface/cmsis-dap.cfg -c 'set USE_CORE 0' -f target/rp2040.cfg -c "adapter speed 5000"` - (Explanation of `USE_CORE`: https://github.com/raspberrypi/debugprobe/issues/45) -- `arm-none-eabi-gdb ./build/rp2040/cmd/sbc_harness/sbc_harness.elf` - ``` - target extended-remote localhost:3333 - monitor reset init - continue - ``` - https://openocd.org/doc/html/General-Commands.html - -SWD: -- https://www.raspberrypi.com/documentation/microcontrollers/debug-probe.html -- https://github.com/raspberrypi/debugprobe -- https://developer.arm.com/documentation/101451/0100/About-CMSIS-DAP - -## Raspberry Pi 3-pin Debug Connector -- https://datasheets.raspberrypi.com/debug/debug-connector-specification.pdf - -| Pin # | UART | ARM SW-DP | cJTAG (IEEE 1149.7) | -|-------|----------------------|------------------------------------|----------------------------------| -| 1 | RX (targetâdebugger) | SC/SWCLK (serial clock) | TMSC - Test Clock Control | -| 2 | GND | GND | GND | -| 3 | TX (targetâdebugger) | SD/SWDIO (bidi serial data) | TCKC - Test Master/Slave Control | -| | | SWO (optional: serial wire output) | | - -## UART (Universal asynchronous receiver/transmitter) - -## ARM SWD (Serial Wire Debug) -- https://developer.arm.com/documentation/101761/1-0/Debug-and-trace-interface/Serial-Wire-Debug-signals -- https://developer.arm.com/documentation/ihi0031/a/The-Serial-Wire-Debug-Port--SW-DP-/Introduction-to-the-ARM-Serial-Wire-Debug--SWD--protocol -- https://arm-software.github.io/CMSIS-DAP/latest/index.html -- ADIv5: https://developer.arm.com/documentation/ihi0031/g/ -- ADIv6: https://developer.arm.com/documentation/ihi0074/e/ - -Alternative to Raspberry Pi Debug Probe: -https://oshwlab.com/wagiminator/samd11c-swd-programmer which uses -https://github.com/ataradov/free-dap instead of ARM's reference CMSIS -implementation - -Note that the RP2040 chip has a pure SW-DP (just speaks SWD), not a -JTAG-DP (just speaks JTAG) or a SWJ-DP (can speak either SWD or JTAG). - -``` -+-[Host PC]-------------------------+ -| | -| +-----+ | -| | GDB | | -| +-----+ | -| ^ | -| | GDB Remote Serial Protocol -| | on localhost:3333 -| V | -| +---------+ | -| | OpenOCD | | -| +---------+ | -| ^ | -| | | -+-----------------|-----------------+ - USB-A - | - | ARM CMSIS-DAP protocol - | (a USB-based protocol) - | - (micro)USB-B - +-[Debug Probe]-------+ - | | | - | V | - | +----------------+ | - | | ARM's | | - | | reference | | - | | CMSIS-DAP | | - | | implementation | | - | +----------------+ | - | ^ | - | | | - +----------|----------+ - SW-DP (3-pin JST-SH) - | - | ADIv5 SWD protocol - | - SW-DP (3 .1" headers) -+-[SBC-Harness]---|-----------------+ -| | | -| ,---------------' | -| | | -| | +----------------------------+ | -| | | Cortex-M0+ | | -| | | +------------------------+ | | -| +--->| CoreSight ADIv5 module | | | -| | | +------------------------+ | | -| | +----------------------------+ | -| | | -| | +----------------------------+ | -| | | Cortex-M0+ | | -| | | +------------------------+ | | -| `--->| CoreSight ADIv5 module | | | -| | +------------------------+ | | -| +----------------------------+ | -| | -+-----------------------------------+ -``` + - picotool 2.1.1-1 + +Then, simply run `make`. This will create +`build/rp2040-*/cmd/sbc_harness/sbc_harness.{elf,bin,hex,uf2}` files: + + - The `.elf` is the firmware image plus debugger symbols and + relocation data. + - The `.bin` file is the raw firmware image (`objcopy -Obinary + INFILE.elf OUTFILE.bin`). + - The `.hex` file is the raw firmware image, encoded in the [Intel + HEX](https://archive.org/details/IntelHEXStandard) format (`objcopy + -Oihex INFILE.elf OUTFILE.hex`). Note that unlike the `.bin`, the + `.hex` may contain gaps/holes; holes are filled with 0x00-bytes in + the `.bin`, but tools for working with the `.hex` may fill them + with other data, causing minor differences when comparing the + `.bin` and `.hex`. (Yes, the `.hex` is expected to be about 2.8 + times the size of the `.bin`; twice for being ASCII-encoded hex, + plus another 13 bytes overhead for every 16 bytes of input.) + - The `.uf2` file is the `.bin` wrapped into a [USB Flashing Format + (UF2)](https://github.com/microsoft/uf2) container that can be used + with the bootrom flasher. (Yes, the `.uf2` is expected to be about + twice the size of the `.bin`; each 128-byte block of input is + wrapped in a 256-byte UF2 block.) + +There are several ways of putting this firmware file onto the harness: + + 1. bootrom flasher: Hold the "BOOTSEL" button when powering on. The + harness will appear to a host PC as a USB storage device. Simply + mount the device and copy the `.uf2` file to the device. It will + automatically reboot into the new firmware image. + 2. debug port: Using OpenOCD (see `HACKING.md`), run the OpenOCD command + `program /path/to/sbc_harness.elf reset` (TODO: I don't really + understand what OpenOCD is doing that it wants the `.elf` instead + of the `.bin`) + . + + If OpenOCD is not already running: + ``` + openocd -f interface/cmsis-dap.cfg -f target/rp2040.cfg -c "program $PWD/build/rp2040-Debug/cmd/sbc_harness/sbc_harness.elf reset exit"` + ``` + + If OpenOCD is already running: + ``` + socat STDIO TCP:localhost:4444 <<<"program $PWD/build/rp2040-Debug/cmd/sbc_harness/sbc_harness.elf reset" + ``` + 3. Use `flashprog` or `flashrom` and a SOIC-8 clip to directly + program the flash chip. I'm not sure why you would do this + instead of one of the above. # Usage The harness uses DHCP to acquire an IPv4 address, then serves the 9P protocol over TCP: - - TCP port: 564 (9P does not have a standard TCP port number, but - this is the default port number used by most 9P-over-TCP clients, - including the Linux kernel's v9fs driver). + - TCP port: 564 - Supported protocol versions: - `9P2000` (base protocol): Yes - `9P2000.u` (Unix extension): Yes, with Linux kernel architecture-"generic" errnos. This will match the Linux kernel - errnos on most architectures (but, as of Linux v6.7, not on - Alpha, MIPS, PA-RISC, PowerPC, or SPARC; I am unsure whether on - these platforms the kernel's v9fs filesystem driver will map the + errnos on most architectures (but, as of Linux v6.14, not on + Alpha, MIPS, PA-RISC, PowerPC, or SPARC; unfortunately on these + platforms the kernel's v9fs filesystem driver won't map the "generic" errnos to the architecture-specific errnos for you). - `9P2000.L` (Linux extension): No, it's an abomination and unlikely to ever be supported @@ -164,28 +92,28 @@ There are lots of 9P clients that you can use. 9P is a filesystem protocol; and you can mount it directly with the the Linux kernel's v9fs filesystem driver, with plan9port's `9pfuse`; or interact with it without mounting it using the shell commands `9p` (from plan9port), -`wmiir`, `ixpc`; or interact with it without mounting it by using a +`wmiir`, or `ixpc`; or interact with it without mounting it by using a library for your programming language of choice. Some notes on choosing a client: - On x86-32, the Linux kernel v9fs driver is known to drop entries - from directory listings; I advise using 9pfuse instead of you want + from directory listings; I advise using 9pfuse instead if you want to mount it on 32-bit systems. - I generally like mounting it as a real filesystem, but this means that you only get errno errors, and the more-helpful error strings are discarded. - - The sbc-harness only supports 8 concurrent connections to the 9P + - The sbc-harness only supports 7 concurrent connections to the 9P server, so while shell commands are handy for poking around, for real use where you're doing things in parallel you'll likely want to mount it or use a library that can reuse existing connections. # Bugs/Limitations - - Only supports 8 concurrent TCP connectsions to the 9P server (due + - Only supports 7 concurrent TCP connectsions to the 9P server (due to limitations in the W5500 TCP-offload chip; TODO: investigate using a software TCP/IP stack with the W5500 in MAC-raw mode) - - Only supports 16 concurrent 9P requests (I wanted a static limit, - and "connections*2" seemed reasonable) + - Only supports 2 concurrent 9P requests per connection (I wanted a + static limit, and 2 seemed reasonable) - Only supports IPv4, not IPv6 (due to limitations in the W5500 TCP-offload chip; TODO: investigate upgrading to the W6100 or using a software TCP/IP stack with the W5500 in MAC-raw mode) |