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=-6.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FROM_EXCESS_BASE64,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_PASS,SUBJ_ALL_CAPS,URIBL_BLOCKED, USER_AGENT_NEOMUTT 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 E9785C43381 for ; Fri, 1 Mar 2019 10:34:56 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (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 2A4A320851 for ; Fri, 1 Mar 2019 10:34:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=yadro.com header.i=@yadro.com header.b="u8GuuV7b" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2A4A320851 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=yadro.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 449m596d9tzDqRy for ; Fri, 1 Mar 2019 21:34:53 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=yadro.com (client-ip=89.207.88.251; helo=mta-01.yadro.com; envelope-from=ilya@yadro.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=yadro.com Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=yadro.com header.i=@yadro.com header.b="u8GuuV7b"; dkim-atps=neutral Received: from mta-01.yadro.com (mta-01.yadro.com [89.207.88.251]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 449m3V2c1qzDqHl for ; Fri, 1 Mar 2019 21:33:26 +1100 (AEDT) Received: from localhost (unknown [127.0.0.1]) by mta-01.yadro.com (Postfix) with ESMTP id D05F241978; Fri, 1 Mar 2019 10:33:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=yadro.com; h= user-agent:in-reply-to:content-transfer-encoding :content-disposition:content-type:content-type:mime-version :references:message-id:subject:subject:from:from:date:date :received:received:received; s=mta-01; t=1551436393; x= 1553250794; bh=SgBOCev7fquOYBn+rGjF4SeZo5oGyiBxj5oGIxzi9nw=; b=u 8GuuV7b0ttH3lhjSWHZXUfPT8/31OLO9WHBO0oE0/4+jmnhrkktmRz+kjG6jE9JX bsKqxvBkHV4hmRd98S80Nxy+QLzJoBjbnAtTdvtY7tt1tOjFsiu6wyyKgiZ/hZMt uZXgDarKnUCWk0Vud9WzsSzJC19SzNs+YYkxQfYJU0= X-Virus-Scanned: amavisd-new at yadro.com Received: from mta-01.yadro.com ([127.0.0.1]) by localhost (mta-01.yadro.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 0VujjfGtY6QF; Fri, 1 Mar 2019 13:33:13 +0300 (MSK) Received: from T-EXCH-02.corp.yadro.com (t-exch-02.corp.yadro.com [172.17.10.102]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by mta-01.yadro.com (Postfix) with ESMTPS id 54D4941974; Fri, 1 Mar 2019 13:33:13 +0300 (MSK) Received: from localhost (172.17.15.183) by T-EXCH-02.corp.yadro.com (172.17.10.102) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P384) id 15.1.669.32; Fri, 1 Mar 2019 13:33:13 +0300 Date: Fri, 1 Mar 2019 13:32:46 +0300 From: =?utf-8?B?0JjQu9GM0Y8g0JrRg9C30L3QtdGG0L7Qsg==?= To: , Benjamin Herrenschmidt Subject: Re: DMA & POWER8 Message-ID: <20190301103246.a6elk7ohpmabqyn7@yadro.com> References: <20190227155702.ngm3l5bjsde2vvrw@yadro.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format=flowed Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20190227155702.ngm3l5bjsde2vvrw@yadro.com> User-Agent: NeoMutt/20180716 X-Originating-IP: [172.17.15.183] X-ClientProxiedBy: T-EXCH-01.corp.yadro.com (172.17.10.101) To T-EXCH-02.corp.yadro.com (172.17.10.102) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: a.fomichev@yadro.com Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" I'm sorry for previous email content without greeting. A bit more description… We are working on enabling RDMA over PCIe NTB on OpenPOWER using https://github.com/ntrdma project. During initialization dma_request_channel() founds no available channels. We also found that there no channels at all in dma_device_list. This is probably powerpc specific problem. Could someone explain if that is hardware limitation or arch specific part should be changed? Ben, a while ago you answered regarding DMA master on POWER8, may be you have idea here also? Thank you in advance! Илья Кузнецов wrote on Ср [2019-фев-27 18:57:02 +0300]: >We're trying to use Slave-DMA API of the DMA Engine in the linux kernel on >POWER8 OpenPOWER platform. And we discovered that dma_request_channel() always fails. >Does it mean that Turismo hardware does not support Slave-DMA? Or DMA >subsystem in the linux kernel needs to be fixed, doesn't it?