From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peng Fan Date: Wed, 9 Sep 2015 11:24:37 +0800 Subject: [U-Boot] [PATCH] usb: gadget: ci_udc: implement usb_ep_ops dequeue callback In-Reply-To: <55EF96B2.4000903@wwwdotorg.org> References: <1440673250-17589-1-git-send-email-Peng.Fan@freescale.com> <20150830072555.GA15009@shlinux2> <55E60048.3090406@wwwdotorg.org> <201509040011.45064.marex@denx.de> <55EF96B2.4000903@wwwdotorg.org> Message-ID: <20150909032434.GA7343@shlinux2> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Tue, Sep 08, 2015 at 07:17:22PM -0700, Stephen Warren wrote: >On 09/03/2015 03:11 PM, Marek Vasut wrote: >> On Tuesday, September 01, 2015 at 09:45:12 PM, Stephen Warren wrote: >>> On 08/30/2015 12:26 AM, Peng Fan wrote: >>>> Hi Stephen, >> >> Hi, >> >> sorry for the delayed reply, I had to dig into the code myself. >> >>>> On Fri, Aug 28, 2015 at 08:05:36AM +0800, Peng Fan wrote: >>>>> Hi Stephen, >>>>> >>>>> On Thu, Aug 27, 2015 at 10:06:14AM -0600, Stephen Warren wrote: >>>>>> On 08/27/2015 05:08 AM, Marek Vasut wrote: >>>>>>> On Thursday, August 27, 2015 at 01:00:50 PM, Peng Fan wrote: >>>>>>>> Implement endpoint dequeue callback function. >>>>>>>> >>>>>>>> Without this function, uboot will hang when executing fastboot >>>>>>>> comamnd. See following flow: >>>>>>>> "fastboot_tx_write_str->fastboot_tx_write->usb_ep_dequeue->ep->ops->d >>>>>>>> equeue " without implement ci_udc dequeue function, ep->ops->dequeue >>>>>>>> is NULL, then uboot will hang. >>>>>>>> >>>>>>>> Tested on mx6qsabresd board with fastboot enabled. >>>>>>>> >>>>>>>> diff --git a/drivers/usb/gadget/ci_udc.c >>>>>>>> b/drivers/usb/gadget/ci_udc.c >>>>>>>> >>>>>>>> +static int ci_ep_dequeue(struct usb_ep *_ep, struct usb_request >>>>>>>> *_req) >>>>>>>> >>>>>>>> + if (ci_req->req.status == -EINPROGRESS) { >>>>>>>> + ci_req->req.status = -ECONNRESET; >>>>>>>> + if (ci_req->req.complete) >>>>>>>> + ci_req->req.complete(_ep, _req); >>>>>>>> + } >>>>>> >>>>>> Is there no need to reprogram the HW to abort the transfer? >>>>> >>>>> I checked linux udc driver drivers/usb/gadget/udc/fsl_qe_udc.c >>>>> qe_ep_dequeue->done->usb_gadget_giveback_request->"req->complete(ep, >>>>> req)" I did not see code to reprogram the HW to abort the transfer. >>>> >>>> Do you have further comments? >>>> I checked other gadget drivers in drivers/usb/gadget/, I did not see >>>> drivers that reprogram the HW to abort the transfer. For now, I do not >>>> think out a scenario to reprogram the HW to abort the transfer >>> >>> Marek, what are the semantics of this function? Is it supposed to simply >>> update SW state to make U-Boot not care about the transaction >> >> Yes, that's correct. >> >>> or is it supposed to actually stop the HW performing the transaction on >>> the USB bus? >> >> No, it's not supposed to kill the transaction in hardware. > >OK, the patch seems fine then. > >>> If it's the former, then the patch is likely fine. If it's the latter, >>> then I think the function does need actually need to do something to >>> make the HW stop, or we can't implement this particular function. >> >> Do we need this for the current release or is this for -next ? > >I assume that's a question for Peng? Since this is a bug fix, I think this patch should be in current release. Without this patch, boards which want to enable fastboot using ci_udc driver will hang. Regards, Peng. > --