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=-13.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham 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 BB046C43387 for ; Wed, 9 Jan 2019 15:02:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 84EE3206BB for ; Wed, 9 Jan 2019 15:02:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ti.com header.i=@ti.com header.b="V+4jgxEu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731942AbfAIPCV (ORCPT ); Wed, 9 Jan 2019 10:02:21 -0500 Received: from fllv0016.ext.ti.com ([198.47.19.142]:50384 "EHLO fllv0016.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731686AbfAIPCV (ORCPT ); Wed, 9 Jan 2019 10:02:21 -0500 Received: from lelv0266.itg.ti.com ([10.180.67.225]) by fllv0016.ext.ti.com (8.15.2/8.15.2) with ESMTP id x09F2FMT022547; Wed, 9 Jan 2019 09:02:15 -0600 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1547046135; bh=tjIam1Hh0q2N2IHJsaY/bqc93Ln54cvop9DBrAyB7A8=; h=Date:From:To:CC:Subject:References:In-Reply-To; b=V+4jgxEu01BAn230NWrG3OCD5IgaEKZa6J/QWr4Xe2QksmluiP27yLcHsE4D5esyw xcWd3eEmCHHwKxoxEaQLGK3/BraGwWLiSI/WOf3BAF44VvcwO1HfGVr+oP/UcGkW8L itet87LicAfuowtvXaY3gRpp5groevJlT5QnCeVo= Received: from DLEE103.ent.ti.com (dlee103.ent.ti.com [157.170.170.33]) by lelv0266.itg.ti.com (8.15.2/8.15.2) with ESMTPS id x09F2F9a050773 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 9 Jan 2019 09:02:15 -0600 Received: from DLEE113.ent.ti.com (157.170.170.24) by DLEE103.ent.ti.com (157.170.170.33) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1591.10; Wed, 9 Jan 2019 09:02:15 -0600 Received: from dflp33.itg.ti.com (10.64.6.16) by DLEE113.ent.ti.com (157.170.170.24) with Microsoft SMTP Server (version=TLS1_0, cipher=TLS_RSA_WITH_AES_256_CBC_SHA) id 15.1.1591.10 via Frontend Transport; Wed, 9 Jan 2019 09:02:15 -0600 Received: from localhost (ileax41-snat.itg.ti.com [10.172.224.153]) by dflp33.itg.ti.com (8.14.3/8.13.8) with ESMTP id x09F2F2D000548; Wed, 9 Jan 2019 09:02:15 -0600 Date: Wed, 9 Jan 2019 09:02:15 -0600 From: Bin Liu To: Paul Elder CC: , , , , , , Subject: Re: [PATCH v2] usb: gadget: musb: fix short isoc packets with inventra dma Message-ID: <20190109150215.GJ25910@uda0271908> Mail-Followup-To: Bin Liu , Paul Elder , laurent.pinchart@ideasonboard.com, kieran.bingham@ideasonboard.com, drinkcat@chromium.org, balbi@kernel.org, gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org References: <20190109071009.27625-1-paul.elder@ideasonboard.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20190109071009.27625-1-paul.elder@ideasonboard.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Paul, On Wed, Jan 09, 2019 at 02:10:09AM -0500, Paul Elder wrote: > Handling short packets (length < max packet size) in the Inventra DMA > engine in the MUSB driver causes the MUSB DMA controller to hang. An > example of a problem that is caused by this problem is when streaming > video out of a UVC gadget, only the first video frame is transferred. > > For short packets (mode-0 or mode-1 DMA), MUSB_TXCSR_TXPKTRDY must be > set manually by the driver. This was previously done in musb_g_tx > (musb_gadget.c), but incorrectly (all csr flags were cleared, and only > MUSB_TXCSR_MODE and MUSB_TXCSR_TXPKTRDY were set). Fixing that problem > allows some requests to be transferred correctly, but multiple requests > were often put together in one USB packet, and caused problems if the > packet size was not a multiple of 4. Instead, set MUSB_TXCSR_TXPKTRDY > in dma_controller_irq (musbhsdma.c), just like host mode transfers. > > This topic was originally tackled by Nicolas Boichat [0] [1] and is > discussed further at [2] as part of his GSoC project [3]. > > [0] https://groups.google.com/forum/?hl=en#!topic/beagleboard-gsoc/k8Azwfp75CU > [1] https://gitorious.org/beagleboard-usbsniffer/beagleboard-usbsniffer-kernel/commit/b0be3b6cc195ba732189b04f1d43ec843c3e54c9?p=beagleboard-usbsniffer:beagleboard-usbsniffer-kernel.git;a=patch;h=b0be3b6cc195ba732189b04f1d43ec843c3e54c9 > [2] http://beagleboard-usbsniffer.blogspot.com/2010/07/musb-isochronous-transfers-fixed.html > [3] http://elinux.org/BeagleBoard/GSoC/USBSniffer > > Signed-off-by: Paul Elder > --- > Changes in v2: > > - no more flushing FIFO > - greatly simplified short packet if guard in musb_g_tx, and removed > unnecessary variables > - minor indentation and wording changes > > drivers/usb/musb/musb_gadget.c | 19 +++++-------------- > drivers/usb/musb/musbhsdma.c | 21 +++++++++++---------- > 2 files changed, 16 insertions(+), 24 deletions(-) > > diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c > index eae8b1b1b45b..496643f54faa 100644 > --- a/drivers/usb/musb/musb_gadget.c > +++ b/drivers/usb/musb/musb_gadget.c > @@ -452,13 +452,10 @@ void musb_g_tx(struct musb *musb, u8 epnum) > } > > if (request) { > - u8 is_dma = 0; > - bool short_packet = false; > > trace_musb_req_tx(req); > > if (dma && (csr & MUSB_TXCSR_DMAENAB)) { > - is_dma = 1; > csr |= MUSB_TXCSR_P_WZC_BITS; > csr &= ~(MUSB_TXCSR_DMAENAB | MUSB_TXCSR_P_UNDERRUN | > MUSB_TXCSR_TXPKTRDY | MUSB_TXCSR_AUTOSET); > @@ -476,16 +473,8 @@ void musb_g_tx(struct musb *musb, u8 epnum) > */ > if ((request->zero && request->length) > && (request->length % musb_ep->packet_sz == 0) > - && (request->actual == request->length)) > - short_packet = true; > + && (request->actual == request->length)) { > > - if ((musb_dma_inventra(musb) || musb_dma_ux500(musb)) && > - (is_dma && (!dma->desired_mode || > - (request->actual & > - (musb_ep->packet_sz - 1))))) > - short_packet = true; > - > - if (short_packet) { > /* > * On DMA completion, FIFO may not be > * available yet... > @@ -493,8 +482,10 @@ void musb_g_tx(struct musb *musb, u8 epnum) > if (csr & MUSB_TXCSR_TXPKTRDY) > return; > > - musb_writew(epio, MUSB_TXCSR, MUSB_TXCSR_MODE > - | MUSB_TXCSR_TXPKTRDY); > + musb_dbg(musb, "sending short pkt (zero=%d, length=%d, actual=%d, dma->desired_mode=%d)\n", > + request->zero, request->length, request->actual, > + dma->desired_mode); > + musb_writew(epio, MUSB_TXCSR, csr | MUSB_TXCSR_TXPKTRDY); Sorry I didn't catch this in the last review, but this change seems not required, isn't it? In the first version of the patch, the code is 'returned' in the 'if (musb_dma_inventra())' branch above, doesn't reach here. Regards, -Bin.