Internal Memo: Porting Intel i226 Driver on JetPack 5

Result

We built a new igc.ko for JetPack 5.1.1 to enable Intel i226 support.

---

This memo documents the development process of porting the Intel i226 driver to JetPack 5.

Background Information

• JetPack 5 officially supports Intel i225-IT, but not Intel i226-IT.

• JetPack 6 officially supports both Intel i225-IT and Intel i226-IT.

• The Intel i225 and Intel i226 drivers are part of the igc driver. Fortunately, igc.ko is built as a loadable kernel module rather than being built into the kernel image on both JetPack 5 and JetPack 6.

• An out-of-tree version of the igc driver exists. It is possible to compile it as an external kernel module using the kernel headers.

---

Backporting Intel i226 Driver

When it comes to backporting, the key is identifying the closest kernel header candidate.

• JetPack 5.1.1 is based on kernel 5.10.104.

• According to Intel’s documentation, support for Intel i226 begins with kernel 5.16.

• Fortunately, kernel 5.10.240 includes a backported igc driver with Intel i226 support.

Steps

• Download the 5.10.240 kernel source from kernel.org:

  wget https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/linux-5.10.240.tar.gz

• Extract the igc folder from: drivers/net/ethernet/intel/igc

• Create a new Makefile to build only the kernel module.

• obj-m := igc.o
  igc-objs := igc_main.o igc_mac.o igc_i225.o igc_base.o igc_nvm.o igc_phy.o \
  igc_diag.o igc_ethtool.o igc_ptp.o igc_dump.o igc_tsn.o 
  
  KDIR := /lib/modules/$(shell uname -r)/build
  PWD  := $(shell pwd)
  
  all:
  	$(MAKE) -C $(KDIR) M=$(PWD) modules
  
  clean:
  	$(MAKE) -C $(KDIR) M=$(PWD) clean
  

• Compile and resolve kernel API conflicts between 5.10.104 and 5.10.240.

  • Ported the igc_ipv6_csum_is_sctp approach from 5.10.104.

  • Disabled the PTM feature in igc_main.c.

• Moved the compiled igc.ko to /lib/modules/5.10.104-tegra/kernel/drivers/net/ethernet/intel/igc/igc.ko, which is the default path for loading the igc kernel module.