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=-11.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 BFEFDC43461 for ; Tue, 1 Sep 2020 17:17:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AC4602087D for ; Tue, 1 Sep 2020 17:17:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732566AbgIARQi (ORCPT ); Tue, 1 Sep 2020 13:16:38 -0400 Received: from verein.lst.de ([213.95.11.211]:54502 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727784AbgIARQg (ORCPT ); Tue, 1 Sep 2020 13:16:36 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id 48CDB68B05; Tue, 1 Sep 2020 19:16:27 +0200 (CEST) Date: Tue, 1 Sep 2020 19:16:27 +0200 From: Christoph Hellwig To: Thomas Bogendoerfer Cc: Christoph Hellwig , alsa-devel@alsa-project.org, linux-ia64@vger.kernel.org, linux-doc@vger.kernel.org, nouveau@lists.freedesktop.org, linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, "James E.J. Bottomley" , linux-mm@kvack.org, Marek Szyprowski , linux-samsung-soc@vger.kernel.org, Joonyoung Shim , linux-scsi@vger.kernel.org, Kyungmin Park , Ben Skeggs , Matt Porter , linux-media@vger.kernel.org, Tom Lendacky , Pawel Osciak , Mauro Carvalho Chehab , linux-arm-kernel@lists.infradead.org, linux-parisc@vger.kernel.org, netdev@vger.kernel.org, Seung-Woo Kim , linux-mips@vger.kernel.org, iommu@lists.linux-foundation.org Subject: Re: [PATCH 22/28] sgiseeq: convert from dma_cache_sync to dma_sync_single_for_device Message-ID: <20200901171627.GA8255@lst.de> References: <20200819065555.1802761-1-hch@lst.de> <20200819065555.1802761-23-hch@lst.de> <20200901152209.GA14288@alpha.franken.de> <20200901171241.GA20685@alpha.franken.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200901171241.GA20685@alpha.franken.de> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-parisc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-parisc@vger.kernel.org On Tue, Sep 01, 2020 at 07:12:41PM +0200, Thomas Bogendoerfer wrote: > On Tue, Sep 01, 2020 at 05:22:09PM +0200, Thomas Bogendoerfer wrote: > > On Wed, Aug 19, 2020 at 08:55:49AM +0200, Christoph Hellwig wrote: > > > Use the proper modern API to transfer cache ownership for incoherent DMA. > > > > > > Signed-off-by: Christoph Hellwig > > > --- > > > drivers/net/ethernet/seeq/sgiseeq.c | 12 ++++++++---- > > > 1 file changed, 8 insertions(+), 4 deletions(-) > > > > > > diff --git a/drivers/net/ethernet/seeq/sgiseeq.c b/drivers/net/ethernet/seeq/sgiseeq.c > > > index 39599bbb5d45b6..f91dae16d69a19 100644 > > > --- a/drivers/net/ethernet/seeq/sgiseeq.c > > > +++ b/drivers/net/ethernet/seeq/sgiseeq.c > > > @@ -112,14 +112,18 @@ struct sgiseeq_private { > > > > > > static inline void dma_sync_desc_cpu(struct net_device *dev, void *addr) > > > { > > > - dma_cache_sync(dev->dev.parent, addr, sizeof(struct sgiseeq_rx_desc), > > > - DMA_FROM_DEVICE); > > > + struct sgiseeq_private *sp = netdev_priv(dev); > > > + > > > + dma_sync_single_for_cpu(dev->dev.parent, VIRT_TO_DMA(sp, addr), > > > + sizeof(struct sgiseeq_rx_desc), DMA_BIDIRECTIONAL); > > > } > > > > > > static inline void dma_sync_desc_dev(struct net_device *dev, void *addr) > > > { > > > - dma_cache_sync(dev->dev.parent, addr, sizeof(struct sgiseeq_rx_desc), > > > - DMA_TO_DEVICE); > > > + struct sgiseeq_private *sp = netdev_priv(dev); > > > + > > > + dma_sync_single_for_device(dev->dev.parent, VIRT_TO_DMA(sp, addr), > > > + sizeof(struct sgiseeq_rx_desc), DMA_BIDIRECTIONAL); > > > } > > > > this breaks ethernet on IP22 completely, but I haven't figured out why, yet. > > the problem is that dma_sync_single_for_cpu() doesn't flush anything > for IP22, because it only flushes for CPUs which do speculation. So > either MIPS arch_sync_dma_for_cpu() should always flush or sgiseeq > needs to use a different sync funktion, when it wants to re-read descriptors > from memory. Well, if IP22 doesn't speculate (which I'm pretty sure is the case), dma_sync_single_for_cpu should indeeed be a no-op. But then there also shouldn't be anything in the cache, as the previous dma_sync_single_for_device should have invalidated it. So it seems like we are missing one (or more) ownership transfers to the device. I'll try to look at the the ownership management in a little more detail tomorrow. 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=-11.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 04D11C433E7 for ; Tue, 1 Sep 2020 17:16:39 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id CB73220767 for ; Tue, 1 Sep 2020 17:16:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="skrwp0i/" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CB73220767 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Vijbp73Jh5Gb0G7cVnHTti+keCg7wueDYxLY8NGfkFM=; b=skrwp0i/QRiin6/Y/Yj+brt6A mmVbkVkmvcU8IH73Tl37UQcGK1bKCTKkGDBlgz0UnAkx8bfDyeuSi8lSXqabumF66f816BJLczWLW Cqjbe0AtF6n9LTRoas0u5tYhPk6uOQB8sUCdeBgPri8hmaFA7q8gE+SjdADCUti8OpKPATmDS21Gr I4JF13K5VkY1UgPHByqygS6LE5RfmMlThA+j5Em8I9add+cmFe9BYPFLysY/tgb1wtp10gS2rYd8d 1uchtELDRRg3o3K3qBdN5tM27bNLSFwHiJl0o/BrDgjPOTnQUc9ihhC/H7fkfnZo9wQTxFEcnuF0+ 8kZMDdz6w==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kD9tc-0003aU-2u; Tue, 01 Sep 2020 17:16:36 +0000 Received: from verein.lst.de ([213.95.11.211]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kD9tW-0003Yf-S5; Tue, 01 Sep 2020 17:16:31 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 48CDB68B05; Tue, 1 Sep 2020 19:16:27 +0200 (CEST) Date: Tue, 1 Sep 2020 19:16:27 +0200 From: Christoph Hellwig To: Thomas Bogendoerfer Subject: Re: [PATCH 22/28] sgiseeq: convert from dma_cache_sync to dma_sync_single_for_device Message-ID: <20200901171627.GA8255@lst.de> References: <20200819065555.1802761-1-hch@lst.de> <20200819065555.1802761-23-hch@lst.de> <20200901152209.GA14288@alpha.franken.de> <20200901171241.GA20685@alpha.franken.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200901171241.GA20685@alpha.franken.de> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200901_131631_133376_438C0DE6 X-CRM114-Status: GOOD ( 22.68 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: alsa-devel@alsa-project.org, linux-ia64@vger.kernel.org, linux-doc@vger.kernel.org, nouveau@lists.freedesktop.org, linux-nvme@lists.infradead.org, linux-mips@vger.kernel.org, "James E.J. Bottomley" , linux-mm@kvack.org, Christoph Hellwig , Marek Szyprowski , linux-samsung-soc@vger.kernel.org, Joonyoung Shim , linux-scsi@vger.kernel.org, iommu@lists.linux-foundation.org, Ben Skeggs , Matt Porter , linux-media@vger.kernel.org, Tom Lendacky , Pawel Osciak , Mauro Carvalho Chehab , linux-arm-kernel@lists.infradead.org, linux-parisc@vger.kernel.org, netdev@vger.kernel.org, Seung-Woo Kim , linux-kernel@vger.kernel.org, Kyungmin Park Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Tue, Sep 01, 2020 at 07:12:41PM +0200, Thomas Bogendoerfer wrote: > On Tue, Sep 01, 2020 at 05:22:09PM +0200, Thomas Bogendoerfer wrote: > > On Wed, Aug 19, 2020 at 08:55:49AM +0200, Christoph Hellwig wrote: > > > Use the proper modern API to transfer cache ownership for incoherent DMA. > > > > > > Signed-off-by: Christoph Hellwig > > > --- > > > drivers/net/ethernet/seeq/sgiseeq.c | 12 ++++++++---- > > > 1 file changed, 8 insertions(+), 4 deletions(-) > > > > > > diff --git a/drivers/net/ethernet/seeq/sgiseeq.c b/drivers/net/ethernet/seeq/sgiseeq.c > > > index 39599bbb5d45b6..f91dae16d69a19 100644 > > > --- a/drivers/net/ethernet/seeq/sgiseeq.c > > > +++ b/drivers/net/ethernet/seeq/sgiseeq.c > > > @@ -112,14 +112,18 @@ struct sgiseeq_private { > > > > > > static inline void dma_sync_desc_cpu(struct net_device *dev, void *addr) > > > { > > > - dma_cache_sync(dev->dev.parent, addr, sizeof(struct sgiseeq_rx_desc), > > > - DMA_FROM_DEVICE); > > > + struct sgiseeq_private *sp = netdev_priv(dev); > > > + > > > + dma_sync_single_for_cpu(dev->dev.parent, VIRT_TO_DMA(sp, addr), > > > + sizeof(struct sgiseeq_rx_desc), DMA_BIDIRECTIONAL); > > > } > > > > > > static inline void dma_sync_desc_dev(struct net_device *dev, void *addr) > > > { > > > - dma_cache_sync(dev->dev.parent, addr, sizeof(struct sgiseeq_rx_desc), > > > - DMA_TO_DEVICE); > > > + struct sgiseeq_private *sp = netdev_priv(dev); > > > + > > > + dma_sync_single_for_device(dev->dev.parent, VIRT_TO_DMA(sp, addr), > > > + sizeof(struct sgiseeq_rx_desc), DMA_BIDIRECTIONAL); > > > } > > > > this breaks ethernet on IP22 completely, but I haven't figured out why, yet. > > the problem is that dma_sync_single_for_cpu() doesn't flush anything > for IP22, because it only flushes for CPUs which do speculation. So > either MIPS arch_sync_dma_for_cpu() should always flush or sgiseeq > needs to use a different sync funktion, when it wants to re-read descriptors > from memory. Well, if IP22 doesn't speculate (which I'm pretty sure is the case), dma_sync_single_for_cpu should indeeed be a no-op. But then there also shouldn't be anything in the cache, as the previous dma_sync_single_for_device should have invalidated it. So it seems like we are missing one (or more) ownership transfers to the device. I'll try to look at the the ownership management in a little more detail tomorrow. _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme 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=-11.5 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 64FDEC433E6 for ; Tue, 1 Sep 2020 17:17:29 +0000 (UTC) Received: from alsa0.perex.cz (alsa0.perex.cz [77.48.224.243]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E5425207D3 for ; Tue, 1 Sep 2020 17:17:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alsa-project.org header.i=@alsa-project.org header.b="YJ9TTWb+" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E5425207D3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=alsa-devel-bounces@alsa-project.org Received: from alsa1.perex.cz (alsa1.perex.cz [207.180.221.201]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa0.perex.cz (Postfix) with ESMTPS id 76FA9170F; Tue, 1 Sep 2020 19:16:37 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz 76FA9170F DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1598980647; bh=BorItmMIFil2sLB2WJyK3azlao9AEfdS3iNuTQaA0X4=; h=Date:From:To:Subject:References:In-Reply-To:Cc:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From; b=YJ9TTWb+fY6yqm0ldvYIMhiw911KOewbBWgRh4eE9+XQPj3gU4WE1rhE1QubS9/Br +qKsu+KMi3WZzcgw/JKhZ0X9L7dMC0o7A7kGSMkhV3eswKqMlquPi2iZZF+50n/6wt /VGcngBats4xhYq2rq7+2VzfHRnPMfWBIV+sk+qY= Received: from alsa1.perex.cz (localhost.localdomain [127.0.0.1]) by alsa1.perex.cz (Postfix) with ESMTP id 22422F8020D; Tue, 1 Sep 2020 19:16:37 +0200 (CEST) Received: by alsa1.perex.cz (Postfix, from userid 50401) id 7457AF80217; Tue, 1 Sep 2020 19:16:35 +0200 (CEST) Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id 45576F801EB for ; Tue, 1 Sep 2020 19:16:28 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz 45576F801EB Received: by verein.lst.de (Postfix, from userid 2407) id 48CDB68B05; Tue, 1 Sep 2020 19:16:27 +0200 (CEST) Date: Tue, 1 Sep 2020 19:16:27 +0200 From: Christoph Hellwig To: Thomas Bogendoerfer Subject: Re: [PATCH 22/28] sgiseeq: convert from dma_cache_sync to dma_sync_single_for_device Message-ID: <20200901171627.GA8255@lst.de> References: <20200819065555.1802761-1-hch@lst.de> <20200819065555.1802761-23-hch@lst.de> <20200901152209.GA14288@alpha.franken.de> <20200901171241.GA20685@alpha.franken.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200901171241.GA20685@alpha.franken.de> User-Agent: Mutt/1.5.17 (2007-11-01) Cc: alsa-devel@alsa-project.org, linux-ia64@vger.kernel.org, linux-doc@vger.kernel.org, nouveau@lists.freedesktop.org, linux-nvme@lists.infradead.org, linux-mips@vger.kernel.org, "James E.J. Bottomley" , linux-mm@kvack.org, Christoph Hellwig , Marek Szyprowski , linux-samsung-soc@vger.kernel.org, Joonyoung Shim , linux-scsi@vger.kernel.org, iommu@lists.linux-foundation.org, Ben Skeggs , Matt Porter , linux-media@vger.kernel.org, Tom Lendacky , Pawel Osciak , Mauro Carvalho Chehab , linux-arm-kernel@lists.infradead.org, linux-parisc@vger.kernel.org, netdev@vger.kernel.org, Seung-Woo Kim , linux-kernel@vger.kernel.org, Kyungmin Park X-BeenThere: alsa-devel@alsa-project.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: "Alsa-devel" On Tue, Sep 01, 2020 at 07:12:41PM +0200, Thomas Bogendoerfer wrote: > On Tue, Sep 01, 2020 at 05:22:09PM +0200, Thomas Bogendoerfer wrote: > > On Wed, Aug 19, 2020 at 08:55:49AM +0200, Christoph Hellwig wrote: > > > Use the proper modern API to transfer cache ownership for incoherent DMA. > > > > > > Signed-off-by: Christoph Hellwig > > > --- > > > drivers/net/ethernet/seeq/sgiseeq.c | 12 ++++++++---- > > > 1 file changed, 8 insertions(+), 4 deletions(-) > > > > > > diff --git a/drivers/net/ethernet/seeq/sgiseeq.c b/drivers/net/ethernet/seeq/sgiseeq.c > > > index 39599bbb5d45b6..f91dae16d69a19 100644 > > > --- a/drivers/net/ethernet/seeq/sgiseeq.c > > > +++ b/drivers/net/ethernet/seeq/sgiseeq.c > > > @@ -112,14 +112,18 @@ struct sgiseeq_private { > > > > > > static inline void dma_sync_desc_cpu(struct net_device *dev, void *addr) > > > { > > > - dma_cache_sync(dev->dev.parent, addr, sizeof(struct sgiseeq_rx_desc), > > > - DMA_FROM_DEVICE); > > > + struct sgiseeq_private *sp = netdev_priv(dev); > > > + > > > + dma_sync_single_for_cpu(dev->dev.parent, VIRT_TO_DMA(sp, addr), > > > + sizeof(struct sgiseeq_rx_desc), DMA_BIDIRECTIONAL); > > > } > > > > > > static inline void dma_sync_desc_dev(struct net_device *dev, void *addr) > > > { > > > - dma_cache_sync(dev->dev.parent, addr, sizeof(struct sgiseeq_rx_desc), > > > - DMA_TO_DEVICE); > > > + struct sgiseeq_private *sp = netdev_priv(dev); > > > + > > > + dma_sync_single_for_device(dev->dev.parent, VIRT_TO_DMA(sp, addr), > > > + sizeof(struct sgiseeq_rx_desc), DMA_BIDIRECTIONAL); > > > } > > > > this breaks ethernet on IP22 completely, but I haven't figured out why, yet. > > the problem is that dma_sync_single_for_cpu() doesn't flush anything > for IP22, because it only flushes for CPUs which do speculation. So > either MIPS arch_sync_dma_for_cpu() should always flush or sgiseeq > needs to use a different sync funktion, when it wants to re-read descriptors > from memory. Well, if IP22 doesn't speculate (which I'm pretty sure is the case), dma_sync_single_for_cpu should indeeed be a no-op. But then there also shouldn't be anything in the cache, as the previous dma_sync_single_for_device should have invalidated it. So it seems like we are missing one (or more) ownership transfers to the device. I'll try to look at the the ownership management in a little more detail tomorrow. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH 22/28] sgiseeq: convert from dma_cache_sync to dma_sync_single_for_device Date: Tue, 1 Sep 2020 19:16:27 +0200 Message-ID: <20200901171627.GA8255@lst.de> References: <20200819065555.1802761-1-hch@lst.de> <20200819065555.1802761-23-hch@lst.de> <20200901152209.GA14288@alpha.franken.de> <20200901171241.GA20685@alpha.franken.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20200901171241.GA20685-I1c7kopa9pxLokYuJOExCg@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Sender: "iommu" To: Thomas Bogendoerfer Cc: alsa-devel-K7yf7f+aM1XWsZ/bQMPhNw@public.gmane.org, linux-ia64-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-doc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, nouveau-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, linux-nvme-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-mips-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, "James E.J. Bottomley" , linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, Christoph Hellwig , linux-samsung-soc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Joonyoung Shim , linux-scsi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, Ben Skeggs , Matt Porter , linux-media-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Tom Lendacky , Pawel Osciak , Mauro Carvalho Chehab , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-parisc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Seung-Woo Kim , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Kyungmin Park List-Id: nouveau.vger.kernel.org On Tue, Sep 01, 2020 at 07:12:41PM +0200, Thomas Bogendoerfer wrote: > On Tue, Sep 01, 2020 at 05:22:09PM +0200, Thomas Bogendoerfer wrote: > > On Wed, Aug 19, 2020 at 08:55:49AM +0200, Christoph Hellwig wrote: > > > Use the proper modern API to transfer cache ownership for incoherent DMA. > > > > > > Signed-off-by: Christoph Hellwig > > > --- > > > drivers/net/ethernet/seeq/sgiseeq.c | 12 ++++++++---- > > > 1 file changed, 8 insertions(+), 4 deletions(-) > > > > > > diff --git a/drivers/net/ethernet/seeq/sgiseeq.c b/drivers/net/ethernet/seeq/sgiseeq.c > > > index 39599bbb5d45b6..f91dae16d69a19 100644 > > > --- a/drivers/net/ethernet/seeq/sgiseeq.c > > > +++ b/drivers/net/ethernet/seeq/sgiseeq.c > > > @@ -112,14 +112,18 @@ struct sgiseeq_private { > > > > > > static inline void dma_sync_desc_cpu(struct net_device *dev, void *addr) > > > { > > > - dma_cache_sync(dev->dev.parent, addr, sizeof(struct sgiseeq_rx_desc), > > > - DMA_FROM_DEVICE); > > > + struct sgiseeq_private *sp = netdev_priv(dev); > > > + > > > + dma_sync_single_for_cpu(dev->dev.parent, VIRT_TO_DMA(sp, addr), > > > + sizeof(struct sgiseeq_rx_desc), DMA_BIDIRECTIONAL); > > > } > > > > > > static inline void dma_sync_desc_dev(struct net_device *dev, void *addr) > > > { > > > - dma_cache_sync(dev->dev.parent, addr, sizeof(struct sgiseeq_rx_desc), > > > - DMA_TO_DEVICE); > > > + struct sgiseeq_private *sp = netdev_priv(dev); > > > + > > > + dma_sync_single_for_device(dev->dev.parent, VIRT_TO_DMA(sp, addr), > > > + sizeof(struct sgiseeq_rx_desc), DMA_BIDIRECTIONAL); > > > } > > > > this breaks ethernet on IP22 completely, but I haven't figured out why, yet. > > the problem is that dma_sync_single_for_cpu() doesn't flush anything > for IP22, because it only flushes for CPUs which do speculation. So > either MIPS arch_sync_dma_for_cpu() should always flush or sgiseeq > needs to use a different sync funktion, when it wants to re-read descriptors > from memory. Well, if IP22 doesn't speculate (which I'm pretty sure is the case), dma_sync_single_for_cpu should indeeed be a no-op. But then there also shouldn't be anything in the cache, as the previous dma_sync_single_for_device should have invalidated it. So it seems like we are missing one (or more) ownership transfers to the device. I'll try to look at the the ownership management in a little more detail tomorrow. 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=-11.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 C5CD1C433E6 for ; Tue, 1 Sep 2020 17:16:36 +0000 (UTC) Received: from hemlock.osuosl.org (smtp2.osuosl.org [140.211.166.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 73E0D20767 for ; Tue, 1 Sep 2020 17:16:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 73E0D20767 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by hemlock.osuosl.org (Postfix) with ESMTP id 5FA7C86F76; Tue, 1 Sep 2020 17:16:36 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from hemlock.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id HGj7WTcKFSAk; Tue, 1 Sep 2020 17:16:35 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by hemlock.osuosl.org (Postfix) with ESMTP id D943486F13; Tue, 1 Sep 2020 17:16:35 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id CF9EDC07FF; Tue, 1 Sep 2020 17:16:35 +0000 (UTC) Received: from silver.osuosl.org (smtp3.osuosl.org [140.211.166.136]) by lists.linuxfoundation.org (Postfix) with ESMTP id C12B1C0051 for ; Tue, 1 Sep 2020 17:16:34 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by silver.osuosl.org (Postfix) with ESMTP id A56C91FE32 for ; Tue, 1 Sep 2020 17:16:34 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from silver.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id GaO-6G9bp1Wx for ; Tue, 1 Sep 2020 17:16:33 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by silver.osuosl.org (Postfix) with ESMTPS id 7BD261FD90 for ; Tue, 1 Sep 2020 17:16:32 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 48CDB68B05; Tue, 1 Sep 2020 19:16:27 +0200 (CEST) Date: Tue, 1 Sep 2020 19:16:27 +0200 From: Christoph Hellwig To: Thomas Bogendoerfer Subject: Re: [PATCH 22/28] sgiseeq: convert from dma_cache_sync to dma_sync_single_for_device Message-ID: <20200901171627.GA8255@lst.de> References: <20200819065555.1802761-1-hch@lst.de> <20200819065555.1802761-23-hch@lst.de> <20200901152209.GA14288@alpha.franken.de> <20200901171241.GA20685@alpha.franken.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200901171241.GA20685@alpha.franken.de> User-Agent: Mutt/1.5.17 (2007-11-01) Cc: alsa-devel@alsa-project.org, linux-ia64@vger.kernel.org, linux-doc@vger.kernel.org, nouveau@lists.freedesktop.org, linux-nvme@lists.infradead.org, linux-mips@vger.kernel.org, "James E.J. Bottomley" , linux-mm@kvack.org, Christoph Hellwig , linux-samsung-soc@vger.kernel.org, Joonyoung Shim , linux-scsi@vger.kernel.org, iommu@lists.linux-foundation.org, Ben Skeggs , Matt Porter , linux-media@vger.kernel.org, Tom Lendacky , Pawel Osciak , Mauro Carvalho Chehab , linux-arm-kernel@lists.infradead.org, linux-parisc@vger.kernel.org, netdev@vger.kernel.org, Seung-Woo Kim , linux-kernel@vger.kernel.org, Kyungmin Park X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On Tue, Sep 01, 2020 at 07:12:41PM +0200, Thomas Bogendoerfer wrote: > On Tue, Sep 01, 2020 at 05:22:09PM +0200, Thomas Bogendoerfer wrote: > > On Wed, Aug 19, 2020 at 08:55:49AM +0200, Christoph Hellwig wrote: > > > Use the proper modern API to transfer cache ownership for incoherent DMA. > > > > > > Signed-off-by: Christoph Hellwig > > > --- > > > drivers/net/ethernet/seeq/sgiseeq.c | 12 ++++++++---- > > > 1 file changed, 8 insertions(+), 4 deletions(-) > > > > > > diff --git a/drivers/net/ethernet/seeq/sgiseeq.c b/drivers/net/ethernet/seeq/sgiseeq.c > > > index 39599bbb5d45b6..f91dae16d69a19 100644 > > > --- a/drivers/net/ethernet/seeq/sgiseeq.c > > > +++ b/drivers/net/ethernet/seeq/sgiseeq.c > > > @@ -112,14 +112,18 @@ struct sgiseeq_private { > > > > > > static inline void dma_sync_desc_cpu(struct net_device *dev, void *addr) > > > { > > > - dma_cache_sync(dev->dev.parent, addr, sizeof(struct sgiseeq_rx_desc), > > > - DMA_FROM_DEVICE); > > > + struct sgiseeq_private *sp = netdev_priv(dev); > > > + > > > + dma_sync_single_for_cpu(dev->dev.parent, VIRT_TO_DMA(sp, addr), > > > + sizeof(struct sgiseeq_rx_desc), DMA_BIDIRECTIONAL); > > > } > > > > > > static inline void dma_sync_desc_dev(struct net_device *dev, void *addr) > > > { > > > - dma_cache_sync(dev->dev.parent, addr, sizeof(struct sgiseeq_rx_desc), > > > - DMA_TO_DEVICE); > > > + struct sgiseeq_private *sp = netdev_priv(dev); > > > + > > > + dma_sync_single_for_device(dev->dev.parent, VIRT_TO_DMA(sp, addr), > > > + sizeof(struct sgiseeq_rx_desc), DMA_BIDIRECTIONAL); > > > } > > > > this breaks ethernet on IP22 completely, but I haven't figured out why, yet. > > the problem is that dma_sync_single_for_cpu() doesn't flush anything > for IP22, because it only flushes for CPUs which do speculation. So > either MIPS arch_sync_dma_for_cpu() should always flush or sgiseeq > needs to use a different sync funktion, when it wants to re-read descriptors > from memory. Well, if IP22 doesn't speculate (which I'm pretty sure is the case), dma_sync_single_for_cpu should indeeed be a no-op. But then there also shouldn't be anything in the cache, as the previous dma_sync_single_for_device should have invalidated it. So it seems like we are missing one (or more) ownership transfers to the device. I'll try to look at the the ownership management in a little more detail tomorrow. _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu 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=-11.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 3C4EAC433E7 for ; Tue, 1 Sep 2020 17:17:55 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0FACC20866 for ; Tue, 1 Sep 2020 17:17:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="XtlsI4XQ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0FACC20866 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=6q3Da9E1ZVhdjtY6mepKQm4lyN8jixXjh1uYH9p3wEE=; b=XtlsI4XQbX9wsjZUaNz11yRqF 9Ajnd1lqjtYybfvLglUhxj77Pxt8NtVDGECrRxDeQzHjR838g1caD3SXs5HXl2UT1byd3Ykxgd96r CbdaBnPEHqgD0HDnj9KR+qNm7hssjWeKPYpl6UqB5vSAUCzHoLaQLnpG51k0hFfZdWqoLggjGT+Rh jrPXPUBpmdNncTjDs+ODah3l3T4PjbDs4mf2ZDzO0AvEqX4bbqVF9pDsYollpSfu0HEnOeS0QXcVk g9aFkMBconbdb2UnoovFGy+azIT+QM5iAmsBbv6uYCE4TsFSKdv1uInyqEVpdQeXCx5F6yVAc/m7U 631k9nyJg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kD9tZ-0003Zs-TE; Tue, 01 Sep 2020 17:16:33 +0000 Received: from verein.lst.de ([213.95.11.211]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kD9tW-0003Yf-S5; Tue, 01 Sep 2020 17:16:31 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 48CDB68B05; Tue, 1 Sep 2020 19:16:27 +0200 (CEST) Date: Tue, 1 Sep 2020 19:16:27 +0200 From: Christoph Hellwig To: Thomas Bogendoerfer Subject: Re: [PATCH 22/28] sgiseeq: convert from dma_cache_sync to dma_sync_single_for_device Message-ID: <20200901171627.GA8255@lst.de> References: <20200819065555.1802761-1-hch@lst.de> <20200819065555.1802761-23-hch@lst.de> <20200901152209.GA14288@alpha.franken.de> <20200901171241.GA20685@alpha.franken.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200901171241.GA20685@alpha.franken.de> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200901_131631_133376_438C0DE6 X-CRM114-Status: GOOD ( 22.68 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: alsa-devel@alsa-project.org, linux-ia64@vger.kernel.org, linux-doc@vger.kernel.org, nouveau@lists.freedesktop.org, linux-nvme@lists.infradead.org, linux-mips@vger.kernel.org, "James E.J. Bottomley" , linux-mm@kvack.org, Christoph Hellwig , Marek Szyprowski , linux-samsung-soc@vger.kernel.org, Joonyoung Shim , linux-scsi@vger.kernel.org, iommu@lists.linux-foundation.org, Ben Skeggs , Matt Porter , linux-media@vger.kernel.org, Tom Lendacky , Pawel Osciak , Mauro Carvalho Chehab , linux-arm-kernel@lists.infradead.org, linux-parisc@vger.kernel.org, netdev@vger.kernel.org, Seung-Woo Kim , linux-kernel@vger.kernel.org, Kyungmin Park Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Sep 01, 2020 at 07:12:41PM +0200, Thomas Bogendoerfer wrote: > On Tue, Sep 01, 2020 at 05:22:09PM +0200, Thomas Bogendoerfer wrote: > > On Wed, Aug 19, 2020 at 08:55:49AM +0200, Christoph Hellwig wrote: > > > Use the proper modern API to transfer cache ownership for incoherent DMA. > > > > > > Signed-off-by: Christoph Hellwig > > > --- > > > drivers/net/ethernet/seeq/sgiseeq.c | 12 ++++++++---- > > > 1 file changed, 8 insertions(+), 4 deletions(-) > > > > > > diff --git a/drivers/net/ethernet/seeq/sgiseeq.c b/drivers/net/ethernet/seeq/sgiseeq.c > > > index 39599bbb5d45b6..f91dae16d69a19 100644 > > > --- a/drivers/net/ethernet/seeq/sgiseeq.c > > > +++ b/drivers/net/ethernet/seeq/sgiseeq.c > > > @@ -112,14 +112,18 @@ struct sgiseeq_private { > > > > > > static inline void dma_sync_desc_cpu(struct net_device *dev, void *addr) > > > { > > > - dma_cache_sync(dev->dev.parent, addr, sizeof(struct sgiseeq_rx_desc), > > > - DMA_FROM_DEVICE); > > > + struct sgiseeq_private *sp = netdev_priv(dev); > > > + > > > + dma_sync_single_for_cpu(dev->dev.parent, VIRT_TO_DMA(sp, addr), > > > + sizeof(struct sgiseeq_rx_desc), DMA_BIDIRECTIONAL); > > > } > > > > > > static inline void dma_sync_desc_dev(struct net_device *dev, void *addr) > > > { > > > - dma_cache_sync(dev->dev.parent, addr, sizeof(struct sgiseeq_rx_desc), > > > - DMA_TO_DEVICE); > > > + struct sgiseeq_private *sp = netdev_priv(dev); > > > + > > > + dma_sync_single_for_device(dev->dev.parent, VIRT_TO_DMA(sp, addr), > > > + sizeof(struct sgiseeq_rx_desc), DMA_BIDIRECTIONAL); > > > } > > > > this breaks ethernet on IP22 completely, but I haven't figured out why, yet. > > the problem is that dma_sync_single_for_cpu() doesn't flush anything > for IP22, because it only flushes for CPUs which do speculation. So > either MIPS arch_sync_dma_for_cpu() should always flush or sgiseeq > needs to use a different sync funktion, when it wants to re-read descriptors > from memory. Well, if IP22 doesn't speculate (which I'm pretty sure is the case), dma_sync_single_for_cpu should indeeed be a no-op. But then there also shouldn't be anything in the cache, as the previous dma_sync_single_for_device should have invalidated it. So it seems like we are missing one (or more) ownership transfers to the device. I'll try to look at the the ownership management in a little more detail tomorrow. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Date: Tue, 01 Sep 2020 17:16:27 +0000 Subject: Re: [PATCH 22/28] sgiseeq: convert from dma_cache_sync to dma_sync_single_for_device Message-Id: <20200901171627.GA8255@lst.de> List-Id: References: <20200819065555.1802761-1-hch@lst.de> <20200819065555.1802761-23-hch@lst.de> <20200901152209.GA14288@alpha.franken.de> <20200901171241.GA20685@alpha.franken.de> In-Reply-To: <20200901171241.GA20685@alpha.franken.de> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Thomas Bogendoerfer Cc: Christoph Hellwig , alsa-devel@alsa-project.org, linux-ia64@vger.kernel.org, linux-doc@vger.kernel.org, nouveau@lists.freedesktop.org, linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, "James E.J. Bottomley" , linux-mm@kvack.org, Marek Szyprowski , linux-samsung-soc@vger.kernel.org, Joonyoung Shim , linux-scsi@vger.kernel.org, Kyungmin Park , Ben Skeggs , Matt Porter , linux-media@vger.kernel.org, Tom Lendacky , Pawel Osciak , Mauro Carvalho Chehab , linux-arm-kernel@lists.infradead.org, linux-parisc@vger.kernel.org, netdev@vger.kernel.org, Seung-Woo Kim , linux-mips@vger.kernel.org, iommu@lists.linux-foundation.org On Tue, Sep 01, 2020 at 07:12:41PM +0200, Thomas Bogendoerfer wrote: > On Tue, Sep 01, 2020 at 05:22:09PM +0200, Thomas Bogendoerfer wrote: > > On Wed, Aug 19, 2020 at 08:55:49AM +0200, Christoph Hellwig wrote: > > > Use the proper modern API to transfer cache ownership for incoherent DMA. > > > > > > Signed-off-by: Christoph Hellwig > > > --- > > > drivers/net/ethernet/seeq/sgiseeq.c | 12 ++++++++---- > > > 1 file changed, 8 insertions(+), 4 deletions(-) > > > > > > diff --git a/drivers/net/ethernet/seeq/sgiseeq.c b/drivers/net/ethernet/seeq/sgiseeq.c > > > index 39599bbb5d45b6..f91dae16d69a19 100644 > > > --- a/drivers/net/ethernet/seeq/sgiseeq.c > > > +++ b/drivers/net/ethernet/seeq/sgiseeq.c > > > @@ -112,14 +112,18 @@ struct sgiseeq_private { > > > > > > static inline void dma_sync_desc_cpu(struct net_device *dev, void *addr) > > > { > > > - dma_cache_sync(dev->dev.parent, addr, sizeof(struct sgiseeq_rx_desc), > > > - DMA_FROM_DEVICE); > > > + struct sgiseeq_private *sp = netdev_priv(dev); > > > + > > > + dma_sync_single_for_cpu(dev->dev.parent, VIRT_TO_DMA(sp, addr), > > > + sizeof(struct sgiseeq_rx_desc), DMA_BIDIRECTIONAL); > > > } > > > > > > static inline void dma_sync_desc_dev(struct net_device *dev, void *addr) > > > { > > > - dma_cache_sync(dev->dev.parent, addr, sizeof(struct sgiseeq_rx_desc), > > > - DMA_TO_DEVICE); > > > + struct sgiseeq_private *sp = netdev_priv(dev); > > > + > > > + dma_sync_single_for_device(dev->dev.parent, VIRT_TO_DMA(sp, addr), > > > + sizeof(struct sgiseeq_rx_desc), DMA_BIDIRECTIONAL); > > > } > > > > this breaks ethernet on IP22 completely, but I haven't figured out why, yet. > > the problem is that dma_sync_single_for_cpu() doesn't flush anything > for IP22, because it only flushes for CPUs which do speculation. So > either MIPS arch_sync_dma_for_cpu() should always flush or sgiseeq > needs to use a different sync funktion, when it wants to re-read descriptors > from memory. Well, if IP22 doesn't speculate (which I'm pretty sure is the case), dma_sync_single_for_cpu should indeeed be a no-op. But then there also shouldn't be anything in the cache, as the previous dma_sync_single_for_device should have invalidated it. So it seems like we are missing one (or more) ownership transfers to the device. I'll try to look at the the ownership management in a little more detail tomorrow.