On Thu, 22 Aug 2019, Benjamin Herrenschmidt wrote: > On Thu, 2019-08-22 at 14:58 +1000, Benjamin Herrenschmidt wrote: > > > > Ah lovely ... the 338x fails in EP autoconf with f_tcm, digging... > > > > While digging I found this gem: > > > > /* USB3380: use same address for usb and hardware endpoints */ > > snprintf(name, sizeof(name), "ep%d%s", usb_endpoint_num(desc), > > usb_endpoint_dir_in(desc) ? "in" : "out"); > > ep = gadget_find_ep_by_name(_gadget, name); > > if (ep && usb_gadget_ep_match_desc(_gadget, ep, desc, ep_comp)) > > return ep; > > > > Any idea what's that supposed to achieve ?
It looks like in one mode, the endpoint number has to be the value predetermined by the hardware. In the other mode, any hardware endpoint can be assigned any endpoint number. > > When ep_match is called, usb_endpoint_num() hasn't been set yet so > > it's always 0 and always fails... or am I missing something ? > > Two problems: > > - net2280.c doesn't set a max EP size, so autoconfig fails since > f_tcm specifies one. What about this ? > > --- a/drivers/usb/gadget/udc/core.c > +++ b/drivers/usb/gadget/udc/core.c > @@ -940,12 +940,14 @@ int usb_gadget_ep_match_desc(struct usb_gadget *gadget, > if (usb_endpoint_dir_out(desc) && !ep->caps.dir_out) > return 0; > > - if (max > ep->maxpacket_limit) > + if (ep->maxpacket_limit && max > ep->maxpacket_limit) > return 0; > > (ie assume that ep->maxpacket_limit 0 means the UDC supports any > legal size) That looks reasonable. > - No UDC driver other than dummy sets max_streams, and f_tcm requires 4, > so f_tcm will fail with *any* superspeed UDC driver as far as I can tell. > > Was it ever tested with USB 3 ? Note that USB 2 does not support streams at all. > I'm not sure what the right fix here yet is as I yet have to learn about > what those USB3 streams are :-) For now I've commented things out. They are for multiplexing multiple data streams over a single USB endpoint. As far as I know, the only use case for such a thing is USB Mass Storage. Alan Stern > It's still not working yet as configuring f_tcm seems to be a black art > with no useful documentation or examples anywhere (the device shows up on > the host but doesn't bind to any mass storage driver ... yet). > > Cheers, > Ben.
