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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 0CE6FC5CFC1 for ; Fri, 15 Jun 2018 19:56:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A9EAC208B2 for ; Fri, 15 Jun 2018 19:56:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A9EAC208B2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=deltatee.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966208AbeFOT4h (ORCPT ); Fri, 15 Jun 2018 15:56:37 -0400 Received: from ale.deltatee.com ([207.54.116.67]:52730 "EHLO ale.deltatee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966065AbeFOT4g (ORCPT ); Fri, 15 Jun 2018 15:56:36 -0400 Received: from guinness.priv.deltatee.com ([172.16.1.162]) by ale.deltatee.com with esmtp (Exim 4.89) (envelope-from ) id 1fTupk-00070u-Dc; Fri, 15 Jun 2018 13:56:33 -0600 To: Serge Semin Cc: linux-kernel@vger.kernel.org, linux-ntb@googlegroups.com, Jon Mason , Dave Jiang , Allen Hubbe , Shyam Sundar S K , Shuah Khan References: <20180609000819.13883-1-logang@deltatee.com> <20180609000819.13883-5-logang@deltatee.com> <20180615194929.GA24025@mobilestation> From: Logan Gunthorpe Message-ID: <6fab7e2b-e7aa-8e67-a318-5ce790677c0d@deltatee.com> Date: Fri, 15 Jun 2018 13:56:28 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: <20180615194929.GA24025@mobilestation> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 172.16.1.162 X-SA-Exim-Rcpt-To: shuah@kernel.org, Shyam-sundar.S-k@amd.com, allenbh@gmail.com, dave.jiang@intel.com, jdmason@kudzu.us, linux-ntb@googlegroups.com, linux-kernel@vger.kernel.org, fancer.lancer@gmail.com X-SA-Exim-Mail-From: logang@deltatee.com Subject: Re: [PATCH 4/8] NTB: ntb_pingpong: Choose doorbells based on port number X-SA-Exim-Version: 4.2.1 (built Tue, 02 Aug 2016 21:08:31 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 15/06/18 01:49 PM, Serge Semin wrote: > Regarding the patch. The idea of using the port number instead of linearised > unique index should also work for Intel/AMD/IDT drivers. But the ports-space > linearization algorithm was created for the case if the real port numbers > would exceed the available Doorbell bits. I thought this might be the case of > multi-ports version of the switchtec driver. Well, the switchtec driver splits its 64 doorbells in two sets, one for each port right now. That will likely have to change when we go to a multi-port implementation. In that case we will have 64 doorbells and a maximum 48 ports. So I don't think we have to concern ourselves with more ports than doorbells. > Needless to say, that if Switchtec driver had the ports-index API implementation, > this patch wouldn't be needed. As I've said, it's impossible to write for the crosslink topology so the clients must support that case. Logan