Rockchip CAN FD Development Guide

Release Version: V1.0.0

Date: 2021-01-26

Security Level: □Top-Secret □Secret □Internal ■Public

DISCLAIMER

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Due to product version upgrades or other reasons, this document may be updated or modified from time to time without any notice.

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Rockchip Electronics Co., Ltd.

Address: No. 18, Area A, Software Park, Tongpan Road, Fuzhou, Fujian Province

Website: www.rock-chips.com

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Preface

Overview

Product Versions

Chip Name	Kernel Version
RK356X	4.4 & 4.19

Intended Audience

This document (guide) is mainly applicable to the following engineers:

Technical support engineers

Software development engineers

Revision History

Date	Version	Author	Description
2021-01-26	V1.0.0	Elaine	First version release

Table of Contents

[TOC]

CAN FD Driver

Driver Files

Driver file location:

drivers/net/can/rockchip/rockchip_canfd.c

DTS Node Configuration

Main parameters:

interrupts = <GIC_SPI 1 IRQ_TYPE_LEVEL_HIGH>; Generates an interrupt signal upon completion.
clock

	clocks = <&cru CLK_CAN1>, <&cru PCLK_CAN1>;
	clock-names = "baudclk", "apb_pclk";
	resets = <&cru SRST_CAN1>, <&cru SRST_P_CAN1>;
	reset-names = "can", "can-apb";

Clock properties for the driver to enable/disable clk; reset properties for resetting the bus each time.

pinctrl

&can1 {
	assigned-clocks = <&cru CLK_CAN1>;
	assigned-clock-rates = <200000000>;
	pinctrl-names = "default";
	pinctrl-0 = <&can1m1_pins>;
	status = "okay";
};

The clock frequency can be modified. If the CAN bit rate is less than or equal to 3M, it is recommended to set the CAN clock to 100M for better signal stability. For bit rates higher than 3M, a clock setting of 200M is sufficient.

Configure the iomux of can_h and can_l for CAN functionality.

Kernel Configuration

Symbol: CANFD_ROCKCHIP [=y]
  | Type  : tristate
  | Prompt: Rockchip CANFD controller
  |   Location:
  |     -> Networking support (NET [=y])
  |       -> CAN bus subsystem support (CAN [=y])
  |         -> CAN Device Drivers
  |           -> Platform CAN drivers with Netlink support (CAN_DEV [=y])
  |   Defined at drivers/net/can/rockchip/Kconfig:10
  |   Depends on: NET [=y] && CAN [=y] && CAN_DEV [=y] && ARCH_ROCKCHIP [=y]

CAN FD Communication Test Tools

canutils is a commonly used CAN communication test tool package, containing 5 independent programs: canconfig, candump, canecho, cansend, cansequence. The functions of these programs are briefly described below:

canconfig

Used to configure CAN bus interface parameters, mainly baud rate and mode.

candump

Receives data from the CAN bus interface and prints it to standard output in hexadecimal, or outputs to a specified file.

canecho

Resends all data received from the CAN bus interface back to the CAN bus interface.

cansend

Sends specified data to the specified CAN bus interface.

cansequence

Automatically and repeatedly sends incrementing numbers to the specified CAN bus interface, or specifies a receive mode to verify the received incrementing numbers.

ip

CAN baud rate, function, and other configurations.

Note: busybox also includes the ip tool, but the busybox version is a stripped-down version that does not support CAN operations. Therefore, verify the ip command version (iproute2) before use.

The above tool packages have detailed compilation instructions available online. If compiling buildroot yourself, simply enable the macros to support the above tool packages:

BR2_PACKAGE_CAN_UTILS=y
BR2_PACKAGE_IPROUTE2=y

CAN FD Common Command Interface

Query current network devices:

ifconfig -a

CAN FD startup:

Bring CAN down:

ip link set can0 down

Set arbitration segment 1M baud rate, data segment 3M baud rate:

ip link set can0 type can bitrate 1000000 dbitrate 3000000 fd on

Print can0 information:

ip -details link show can0

Bring CAN up:

ip link set can0 up

CAN FD transmission:

Send (standard frame, data frame, ID:123, data:DEADBEEF):

cansend can0 123##1DEADBEEF

Send (extended frame, data frame, ID:00000123, data:DEADBEEF):

cansend can0 00000123##1DEADBEEF

CAN FD reception:

Enable printing, wait for reception:

candump can0

CAN FD Driver​

Driver Files​

DTS Node Configuration​

Kernel Configuration​

CAN FD Communication Test Tools​

CAN FD Common Command Interface​