evan
bff6405afc
The 7.7k-line qemu-wasm patch was really a fork, so vendor it as a submodule (pinned at the xteink QEMU fork) and build it directly. Removes the clone/commit-check/patch/reset machinery, the redundant web-dev/patch targets, and 0002-qemu-wasm.patch. Editing third_party/qemu now recompiles incrementally via plain `make web`. Native build keeps 0001-xteink-machine.patch.
96 lines
4.2 KiB
Markdown
96 lines
4.2 KiB
Markdown
# xteink-web-emulator
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An offline, in-browser emulator for the xteink **X3/X4** (ESP32-C3 + e-ink):
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upload a firmware `.bin`, run the real machine code client-side, see the screen,
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press buttons, mount a virtual SD — no server, no proprietary engine.
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**Status:** native and WebAssembly builds provide one `xteink` machine that
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selects X3 or X4 at launch. Unmodified
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[canonical firmware](https://github.com/crosspoint-reader/crosspoint-reader)
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auto-detects the selected variant: X3 boots with its UC8253 display and SD card;
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X4 reaches its SSD1677 driver through a blank protocol stub. A basic static
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browser UI now loads local firmware, renders the panel, and drives the physical
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buttons. See [ROADMAP.md](./ROADMAP.md) for architecture and plan.
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## Quick start (native QEMU)
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```sh
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git clone --recursive https://github.com/crosspoint-reader/crosspoint-reader ../crosspoint-reader
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# Build ../crosspoint-reader's PlatformIO `default` environment first.
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nix develop
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make qemu # clone espressif/qemu @ pinned commit, apply patch, build
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make firmware sdimage # 16 MB flash.bin + FAT32 sd.img from the PlatformIO build
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make run # X3 (default)
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make run VARIANT=x4 # X4 detection + blank SSD1677 stub
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```
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Point at a firmware build with `make firmware FIRMWARE_DIR=/path/to/.pio/build/gh_release`.
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`make qemu` is a long compile on modest hardware — set `JOBS` to taste.
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## WebAssembly build
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Podman or Docker is required. The QEMU source is the `third_party/qemu`
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submodule, so initialize it first:
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```sh
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git submodule update --init third_party/qemu
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```
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The build is limited to `riscv32-softmmu` and the X3/X4 device graph;
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networking, audio, virtfs, tools, docs, and unrelated boards are disabled.
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```sh
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make qemu-wasm
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# dist/wasm/qemu-system-riscv32.{js,wasm,worker.js} + esp32c3-rom.bin
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```
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The build runs Node smoke checks when Node is available.
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## Browser interface
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```sh
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make web
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# Open http://127.0.0.1:8000/web/
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```
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Choose a CrossPoint firmware `.bin` — either the ~5 MB release app image (it is
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merged in-browser with the bundled bootloader and partition table into a 16 MB
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flash) or a full 16 MB image — select X3 or X4, and boot. The controls
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map to the device's ADC button ladders and active-low Power GPIO. `make web`
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serves the required COOP/COEP headers for Emscripten pthreads; a generic static
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server without those headers will not work.
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Real firmware boots in WASM and drives the X3 panel (528×792). The browser SD
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uses QEMU's directory-backed FAT provider: the guest sees a writable, ephemeral
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32 GiB FAT32 card while memory use scales with actual files instead of logical
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capacity. It starts with `Test/example.txt`; inspect it in the Files tab. The
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Debug tab reports committed WASM heap, visible MEMFS data, SD file bytes, and
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browser JS heap where supported. X4 remains a white display stub.
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## Contents
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- `qemu/patches/0001-xteink-machine.patch` — the `xteink,variant=x3|x4` machine
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and its device models (I²C fingerprints, ADC, GPIO, SPI2, X3 UC8253, X4 panel
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stub, SD-over-SPI fix), applied onto the pinned espressif/qemu commit by
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`scripts/build-qemu.sh`.
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- `third_party/qemu` — submodule of the [xteink QEMU fork](git@ssh.gitea.va.reichard.io:evan/qemu-xteink.git)
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(espressif/qemu + the machine models + the wasm32 TCG backend), built for the
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browser by `scripts/build-qemu-wasm.sh`. Edit it in place; `make web`
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recompiles incrementally. `qemu/wasm/Dockerfile` is the pinned Emscripten
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dependency environment.
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- `flake.nix` — the espressif-qemu *release* binary as the fast generic baseline
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(`nix run .#run-upstream -- flash.bin`), plus a devShell with QEMU's full build
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environment. `Makefile` — `qemu`, `firmware`, `sdimage`, `run`, `chip`.
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- `scripts/mksd.sh` — build the FAT32 SD backing image (local-disk impl of the
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SD block interface).
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- `chip/eink-x3.chip.c` — the reverse-engineered X3 e-ink protocol, first written
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as a Wokwi chip and now the reference for the QEMU display device.
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`make -C chip test` runs its host self-check.
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## Why not Wokwi
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Wokwi runs any bin in a browser and we had the e-ink chip working — but its
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simulation engine is proprietary and gated behind a license/service, so it can't
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be self-hosted or run airgapped. QEMU is the open path; the e-ink protocol work
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carried straight over.
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