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=-9.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT 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 ACB42C43387 for ; Wed, 9 Jan 2019 07:10:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6C4EF20821 for ; Wed, 9 Jan 2019 07:10:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="uwHupPkp" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729957AbfAIHKf (ORCPT ); Wed, 9 Jan 2019 02:10:35 -0500 Received: from perceval.ideasonboard.com ([213.167.242.64]:50432 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729158AbfAIHKd (ORCPT ); Wed, 9 Jan 2019 02:10:33 -0500 Received: from localhost.localdomain (unknown [96.44.9.117]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 2B2DC56D; Wed, 9 Jan 2019 08:10:30 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1547017831; bh=CDwyaoUsdx/TBITpDivgHrnF++KmX3Jy7YDopjvE9ps=; h=From:To:Cc:Subject:Date:From; b=uwHupPkpTMQXq/akMOnJmKXAk53VzQh+Bpq1ncLt9oAOdvShR/m75G5e9Mg8M8z+W e1vHnxWDTQtlNHy5Z42TCnnqRykZmf29YOHJLSaLqwA+BPg5mvwhfBQwGvM5DMk8qp p/IHogtHyQ9ugnRNBmjoI86Pg8D4SSMjsBVq1zXY= From: Paul Elder To: laurent.pinchart@ideasonboard.com, kieran.bingham@ideasonboard.com Cc: Paul Elder , drinkcat@chromium.org, b-liu@ti.com, balbi@kernel.org, gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] usb: gadget: musb: fix short isoc packets with inventra dma Date: Wed, 9 Jan 2019 02:10:09 -0500 Message-Id: <20190109071009.27625-1-paul.elder@ideasonboard.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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); request->zero = 0; } diff --git a/drivers/usb/musb/musbhsdma.c b/drivers/usb/musb/musbhsdma.c index a688f7f87829..5fc6825745f2 100644 --- a/drivers/usb/musb/musbhsdma.c +++ b/drivers/usb/musb/musbhsdma.c @@ -346,12 +346,10 @@ static irqreturn_t dma_controller_irq(int irq, void *private_data) channel->status = MUSB_DMA_STATUS_FREE; /* completed */ - if ((devctl & MUSB_DEVCTL_HM) - && (musb_channel->transmit) - && ((channel->desired_mode == 0) - || (channel->actual_len & - (musb_channel->max_packet_sz - 1))) - ) { + if (musb_channel->transmit && + (!channel->desired_mode || + (channel->actual_len % + musb_channel->max_packet_sz))) { u8 epnum = musb_channel->epnum; int offset = musb->io.ep_offset(epnum, MUSB_TXCSR); @@ -363,11 +361,14 @@ static irqreturn_t dma_controller_irq(int irq, void *private_data) */ musb_ep_select(mbase, epnum); txcsr = musb_readw(mbase, offset); - txcsr &= ~(MUSB_TXCSR_DMAENAB + if (channel->desired_mode == 1) { + txcsr &= ~(MUSB_TXCSR_DMAENAB | MUSB_TXCSR_AUTOSET); - musb_writew(mbase, offset, txcsr); - /* Send out the packet */ - txcsr &= ~MUSB_TXCSR_DMAMODE; + musb_writew(mbase, offset, txcsr); + /* Send out the packet */ + txcsr &= ~MUSB_TXCSR_DMAMODE; + txcsr |= MUSB_TXCSR_DMAENAB; + } txcsr |= MUSB_TXCSR_TXPKTRDY; musb_writew(mbase, offset, txcsr); } -- 2.20.1