On Tue, Apr 12, 2022 at 11:00 PM Khalid F. Sabzwari <kfsabzwari@yahoo.com> wrote:

Hi,

Hello,

My CPU is Intel x86 (Broadwell DE). I want to write to the command register of the management ethernet PHY's PCIe
config space during Linux boot up. And I want to do that before kernel start loading the igb (ethernet) driver for this PHY.
Can I do that inside the start_kernel() routine in init.main.c, or is the driver is already installed once code reaches this point (I am assuming probably not) ?
If this is the correct routine to do this job, is there any kernel code that I can use to write to this config space?

I dont think this right way, there should be a phy.h header file in kernel and i think should use PHY Abstraction Layer.

https://docs.kernel.org/networking/phy.html

I have bus/device/function info for this management PHY which is already set by the BIOS.

thanks,
Khalid.