On Thu, Jan 16, 2025, Andy Shevchenko wrote:
> On some platforms (Intel-based and AFAIK ARM-based) the EPs in the gadget
> (USB Device Controller mode) may be reserved for some special means, such as
> tracing. This series extends DT schema and driver to avoid using those.
> Without this the USB gadget mode won't work properly (those devices that
> "luckily" allocated the reserved EPs).
>
> Ferry already tested the privately sent PoC of this, but I ask him again to
> re-test this version which is slightly different.
>
> Andy Shevchenko (3):
> dt-bindings: usb: dwc3: Add a property to reserve endpoints
> usb: dwc3: gadget: Add support for snps,reserved-endpoints property
> usb: dwc3: gadget: Skip endpoints ep[18]{in,out} on Intel Merrifield
>
> .../devicetree/bindings/usb/snps,dwc3.yaml | 10 +++++
> drivers/usb/dwc3/dwc3-pci.c | 9 +++++
> drivers/usb/dwc3/gadget.c | 38 ++++++++++++++++++-
> 3 files changed, 56 insertions(+), 1 deletion(-)
>
> --
> 2.43.0.rc1.1336.g36b5255a03ac
>
I'm not entirely clear on the reason for this change yet.
How would this even work without dwc3 managing these endpoints (all the
init/teardown/fifo allocation/start/stop flow). Can you provide more
info on this hardware?
Thanks,
Thinh
