Enable PCIe2 on USBH4

Technical Support
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1

Hi,
we’re trying to enable the secondary PCI express on Apalis-TK1. I could not find any references on how to setup device tree in linux or u-boot in order to reconfigure USBH4 to PCIE2.

The apalis-tk1 datasheet specifies in table “6-22 PCIe mapping” the different use cases. However there seems to be no information on how to alter the configuration which parameters to change and which values to use.

A closer look at the device tree for tegra124-apalis-eval.dts we find references to xusb@70009000 and configuration registries for enabling USB 3.0 lanes. However we cannot find any information on which values should be configured to disable USBH4 and instead use PCIe2.

Which registries we need to reconfigure to enable PCIe2 on USBH4 pins?

Best regards
//Martin

2

Good questions. However so far we have not validated any such configuration at all and therefore also do not really know how/what exactly would need changing. Assuming you do have a custom carrier board which allows you testing such a configuration I suggest for you to first try with a mainline Linux kernel as the whole pin muxing et. al. is much cleaner there truly limited to the device tree only. As you can see here your requested configuration should actually already be the default and basically just work. You may use the Toradex Easy Installer to install our pre-built mainline demo image.

3

Thanks for the hints looks promising :slight_smile:
I’ll try and get back once I’ve tested on our carrier.