Hi Niklas

On Fri, 3 Jan 2025 at 20:40, Niklas Cassel [off-list ref] wrote:

On Fri, Jan 03, 2025 at 08:36:18PM +0530, Anand Moon wrote:

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We need to enable the GMAC PHY and reset it using the proper GPIO pin
(PCIE_PERST_L).
Please refer to the schematic for more details.

The PERST# GPIO is already asserted + deasserted from the PCIe Root Complex
(host) driver:
https://github.com/torvalds/linux/blob/v6.13-rc5/drivers/pci/controller/dwc/pcie-dw-rockchip.c#L191-L206

which will cause the endpoint device (a RTL8125 NIC in this case)
to be reset during bootup.

Thanks for letting me know. It seems like a workaround.
I'll try to disable this and test it again.

My point is that we haven't enabled the GMAC PHY (device nodes)
and must properly reset the GMAC.

We're relying on the code above hack to do that job.

I do not think it is a hack.

If you look in most PCIe controller drivers, they toggle PERST before
enumerating the bus:
$ git grep gpiod_set_value drivers/pci/controller/

Ok, understood. However, we have multiple reset lines per controller,
so the PCIe driver will reset these lines using gpiod_set_value.

PCIE30X4_PERSTn_M1_L
PCIE30x1_0_PERSTn_M1_L
PCIE_PERST_L

Kind regards,
Niklas

Thanks
-Anand