Re-enumerate PCI devices after boot

[khe]

Hi,

I have an Orin Nano where I want to re-enumerate the PCI devices after boot since I have a FPGA that needs a bit-stream programmed before the device will show up.
I got some inspiration from a previous post;

Force rescan of PCIe bus?

Is there a way to force the PCIe bus to re-scan all devices after boot? This is quite useful for developing FPGA based PCIe devices, which are rebooted frequently in dev. The internet says the proper way is this, but it seems to have no effect on the TX1: echo 1 > /sys/bus/pci/rescan

Based on the last comment in that thread I can get it to work by commenting out the part suggested in drivers/pci/controller/dwc/pcie-tegra194.c at line 1675.

	// pcie->link_state = tegra_pcie_dw_link_up(&pcie->pci);
	// if (!pcie->link_state) {
	// 	ret = -ENOMEDIUM;
	// 	goto fail_host_init;
	// }

It is also suggested that the property “nvidia,enable-power-down” can be removed from DTS, but it doesn’t seem to exist for tegra234 (Orin Nano). It looks like a prettier solutions as it can be done through an DTS overlay, but unfortunately not possible.

I only need one specific root port to stay enabled and not all like the driver patch does.

My question is;
What is the best way to keep a specific PCI root port enabled?

[sgidel]

You almost had it. The property you need to add is nvidia,disable-power-down
Im using this on my carrier board and it works well.