From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 702C5C3A5A3 for ; Thu, 22 Aug 2019 17:30:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 52D2B23405 for ; Thu, 22 Aug 2019 17:30:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392118AbfHVRaM (ORCPT ); Thu, 22 Aug 2019 13:30:12 -0400 Received: from iolanthe.rowland.org ([192.131.102.54]:52708 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S2392115AbfHVRaL (ORCPT ); Thu, 22 Aug 2019 13:30:11 -0400 Received: (qmail 3634 invoked by uid 2102); 22 Aug 2019 13:30:10 -0400 Received: from localhost (sendmail-bs@127.0.0.1) by localhost with SMTP; 22 Aug 2019 13:30:10 -0400 Date: Thu, 22 Aug 2019 13:30:10 -0400 (EDT) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: Benjamin Herrenschmidt cc: USB list , Sebastian Andrzej Siewior Subject: Re: f_mass_storage vs drivers/target In-Reply-To: <4c8a9941fb54dffd823335c9f4bc01f3158fb1d5.camel@kernel.crashing.org> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org 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.