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

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

@@ -1,22 +1,39 @@
 # 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. All car ports live in `openpilot/selfdrive/car/car_specific.py` and `opendbc_repo/opendbc/car`.
+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:
 
-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 from car and builds openpilot CarState message
+* `carstate.py`: Reads CAN messages from the car and builds openpilot CarState messages
-* `carcontroller.py`: Builds CAN messages to send to car
+* `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
+* `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
 
-# Overiew
+# 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://youtu.be/KcfzEHB6ms4?si=5szh1PX6TksOCKmM
+https://www.youtube.com/watch?v=XxPS5TpTUnI

selfdrive/car/README.md

@@ -1,19 +0,0 @@
-## Car port structure
-
-### interface.py
-Generic interface to send and receive messages from CAN (controlsd uses this to communicate with car)
-
-### fingerprints.py
-Fingerprints for matching to a specific car
-
-### carcontroller.py
-Builds CAN messages to send to car
-
-##### carstate.py
-Reads CAN from car and builds openpilot CarState message
-
-##### values.py
-Limits for actuation, general constants for cars, and supported car documentation
-
-##### radar_interface.py
-Interface for parsing radar points from the car