libremarkable: A C repository from chriscohoat

libremarkable - A Framework for Remarkable Tablet

Everything from low latency partial updates to the eInk display to multitouch, physical button and Wacom Digitizer input is now understood and their minimal to complete implementations can be found in this repository.

This repository implements a Rust library for providing these features. Potentially a piston backend might be created for Remarkable, allowing the use of conrod to simplify UI creation. For further documentation see the wiki on this repository.

https://github.com/canselcik/RemarkableFramebuffer redirects to this repository for historical purposes.

Build Instructions

Setting up the toolchain

In order to build libremarkable and the examples (spy.so and demo), you'll need the toolchain from Remarkable. Download the installation script (rM2) and install the toolchain. You can find more information on the wiki.

You can then set up your Rust toolchain for cross compilation with: rustup target add armv7-unknown-linux-gnueabihf.

In order for rust to leverage the toolchain a .cargo/config file is required. This file can be generated using gen_cargo_config.py. First the toolchain environment must be sourced. Its location is can be found within the toolchain installation directory. The correct path is also referenced in the toolchain wiki. After the environment is loaded the script will read the environment variables to generate the correct .cargo/config file for your toolchain.

The resulting config file will look something like this:

[target.armv7-unknown-linux-gnueabihf]
linker = "<toolchain_install_path>/sysroots/x86_64-codexsdk-linux/usr/bin/arm-remarkable-linux-gnueabi/arm-remarkable-linux-gnueabi-gcc"
rustflags = [
  "-C", "link-arg=-march=armv7-a",
  "-C", "link-arg=-marm",
  "-C", "link-arg=-mfpu=neon",
  "-C", "link-arg=-mfloat-abi=hard",
  "-C", "link-arg=-mcpu=cortex-a9",
  "-C", "link-arg=--sysroot=<toolchain_install_path>/sysroots/cortexa7hf-neon-remarkable-linux-gnueabi",
]

You can also add this snippet to the above file in order to default to cross-compiling for this project:

[build]
# Set the default --target flag
target = "armv7-unknown-linux-gnueabihf"

Building libremarkable and the examples

A simple Makefile wrapper is created for convenience. It exposes the following verbs:

examples: Builds examples
library: Builds library
all: library + examples

Testing libremarkable and the examples on the device

The provided Makefile assumes the device is reachable at 10.11.99.1 and that SSH Key-Based Authentication is set up for SSH so that you won't be prompted a password every time. The following actions are available:

run: Builds and runs demo.rs on the device after stopping xochitl
start-xochitl: Stops all xochitl and demo instances and starts xochitl normally
spy-xochitl: Builds spy.rs and LD_PRELOADs it to a new instance of xochitl after stopping the current instance. This allows discovery of new enums used by official programs in calls to ioctl.

Further build instructions for manual builds

If you choose to skip the Makefile and call cargo yourself, make sure to include --release --target=armv7-unknown-linux-gnueabihf in your arguments like:

➜  rust-poc git:(master) ✗ cargo build --release --target=armv7-unknown-linux-gnueabihf
   ...
   Compiling libremarkable v0.1.0 (file:///home/main/Desktop/libremarkable)
   Compiling rust-poc v0.1.0 (file:///home/main/Desktop/RemarkableFramebuffer/rust-poc)
    Finished dev [unoptimized + debuginfo] target(s) in 24.85 secs

The --release argument is important as this enables optimizations and without optimizations you'll be looking at ~70% CPU utilization even when idle. With optimizations, the framework runs really light, 0% CPU utilization when idle and 1-2% at peak.

Building with `cross`

Building this way does not require reMarkable's toolchain nor building on Ubuntu 16.04 with Docker so setting up should be easier.

Install cross with cargo install cross. Make sure the reMarkable toolchain is not in use first.

To build, deploy and run the demo, simply:

make TARGET=armv7-unknown-linux-gnueabihf deploy-x-demo
# This builds with
#   cross build --example demo --release --target=armv7-unknown-linux-gnueabihf
# then deploys the demo

Using `musl`

Compile with cross build --example demo --release --target=armv7-unknown-linux-musleabihf (or make x-demo)
Run the demo: make deploy-x-demo

Regarding apps for the rM2: you will need the display package from Toltec. Only the server part though as the client is built into this lib.

Legacy C implementation

The first draft of libremarkable was a C library, built while reverse engineering the tablet. It's no longer maintained, but can be found on the legacy-c-impl branch.

chriscohoat/libremarkable