openpilot0/docs/car-porting/what-is-a-car-port.md

# What is a car port?

A car port enables openpilot support on a particular car. Each car model openpilot supports needs to be individually ported. The complexity of a car port varies depending on many factors including:

* existing openpilot support for similar cars
* architecture and APIs available in the car


# Structure of a car port

Virtually all car-specific code is contained in two other repositories: [opendbc](https://github.com/commaai/opendbc) and [panda](https://github.com/commaai/panda).

## opendbc

Each car brand is supported by a standard interface structure in `opendbc/car/[brand]`:

* `interface.py`: Interface for the car, defines the CarInterface class
* `carstate.py`: Reads CAN messages from the car and builds openpilot CarState messages
* `carcontroller.py`: Control logic for executing openpilot CarControl actions on the car
* `[brand]can.py`: Composes CAN messages for carcontroller to send
* `values.py`: Limits for actuation, general constants for cars, and supported car documentation
* `radar_interface.py`: Interface for parsing radar points from the car, if applicable

## panda

* `board/safety/safety_[brand].h`: Brand-specific safety logic
* `tests/safety/test_[brand].py`: Brand-specific safety CI tests

## openpilot

For historical reasons, openpilot still contains a small amount of car-specific logic. This will eventually be migrated to opendbc or otherwise removed.

* `selfdrive/car/car_specific.py`: Brand-specific event logic

# Overview

[Jason Young](https://github.com/jyoung8607) gave a talk at COMMA_CON with an overview of the car porting process. The talk is available on YouTube:

https://www.youtube.com/watch?v=XxPS5TpTUnI
setup new docs.comma.ai (#32813) * start with mkdocs * some structure * little more old-commit-hash: 0c3f1dc016513037643a4ba2765233bb72b83fce 2024-06-24 04:16:39 +08:00			`# What is a car port?`

docs: car port info cleanup (#33630) * GC, now duplicated and out of place * typo fix * link to official video with better slides * expansion and cleanup 2024-09-24 04:39:36 +08:00			`A car port enables openpilot support on a particular car. Each car model openpilot supports needs to be individually ported. The complexity of a car port varies depending on many factors including:`
setup new docs.comma.ai (#32813) * start with mkdocs * some structure * little more old-commit-hash: 0c3f1dc016513037643a4ba2765233bb72b83fce 2024-06-24 04:16:39 +08:00
mvp of new docs.comma.ai (#32926) * ssh docs * strict * need an index * push to prod old-commit-hash: f6189568eab0244ed792ef299fb781cc4c92fb9b 2024-07-09 07:55:16 +08:00			`* existing openpilot support for similar cars`
			`* architecture and APIs available in the car`


			`# Structure of a car port`
docs: car port info cleanup (#33630) * GC, now duplicated and out of place * typo fix * link to official video with better slides * expansion and cleanup 2024-09-24 04:39:36 +08:00
			`Virtually all car-specific code is contained in two other repositories: [opendbc](https://github.com/commaai/opendbc) and [panda](https://github.com/commaai/panda).`

			`## opendbc`

			Each car brand is supported by a standard interface structure in `opendbc/car/[brand]`:

mvp of new docs.comma.ai (#32926) * ssh docs * strict * need an index * push to prod old-commit-hash: f6189568eab0244ed792ef299fb781cc4c92fb9b 2024-07-09 07:55:16 +08:00			* `interface.py`: Interface for the car, defines the CarInterface class
docs: car port info cleanup (#33630) * GC, now duplicated and out of place * typo fix * link to official video with better slides * expansion and cleanup 2024-09-24 04:39:36 +08:00			* `carstate.py`: Reads CAN messages from the car and builds openpilot CarState messages
			* `carcontroller.py`: Control logic for executing openpilot CarControl actions on the car
			* `[brand]can.py`: Composes CAN messages for carcontroller to send
mvp of new docs.comma.ai (#32926) * ssh docs * strict * need an index * push to prod old-commit-hash: f6189568eab0244ed792ef299fb781cc4c92fb9b 2024-07-09 07:55:16 +08:00			* `values.py`: Limits for actuation, general constants for cars, and supported car documentation
docs: car port info cleanup (#33630) * GC, now duplicated and out of place * typo fix * link to official video with better slides * expansion and cleanup 2024-09-24 04:39:36 +08:00			* `radar_interface.py`: Interface for parsing radar points from the car, if applicable

			`## panda`

			* `board/safety/safety_[brand].h`: Brand-specific safety logic
			* `tests/safety/test_[brand].py`: Brand-specific safety CI tests

			`## openpilot`

			`For historical reasons, openpilot still contains a small amount of car-specific logic. This will eventually be migrated to opendbc or otherwise removed.`
mvp of new docs.comma.ai (#32926) * ssh docs * strict * need an index * push to prod old-commit-hash: f6189568eab0244ed792ef299fb781cc4c92fb9b 2024-07-09 07:55:16 +08:00
docs: car port info cleanup (#33630) * GC, now duplicated and out of place * typo fix * link to official video with better slides * expansion and cleanup 2024-09-24 04:39:36 +08:00			* `selfdrive/car/car_specific.py`: Brand-specific event logic
mvp of new docs.comma.ai (#32926) * ssh docs * strict * need an index * push to prod old-commit-hash: f6189568eab0244ed792ef299fb781cc4c92fb9b 2024-07-09 07:55:16 +08:00
docs: car port info cleanup (#33630) * GC, now duplicated and out of place * typo fix * link to official video with better slides * expansion and cleanup 2024-09-24 04:39:36 +08:00			`# Overview`
mvp of new docs.comma.ai (#32926) * ssh docs * strict * need an index * push to prod old-commit-hash: f6189568eab0244ed792ef299fb781cc4c92fb9b 2024-07-09 07:55:16 +08:00
			`[Jason Young](https://github.com/jyoung8607) gave a talk at COMMA_CON with an overview of the car porting process. The talk is available on YouTube:`

docs: car port info cleanup (#33630) * GC, now duplicated and out of place * typo fix * link to official video with better slides * expansion and cleanup 2024-09-24 04:39:36 +08:00			`https://www.youtube.com/watch?v=XxPS5TpTUnI`