From patchwork Thu May 23 22:30:54 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Logan Gunthorpe X-Patchwork-Id: 10958855 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 602121395 for ; Thu, 23 May 2019 22:31:14 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4C90428609 for ; Thu, 23 May 2019 22:31:14 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 410F32863E; Thu, 23 May 2019 22:31:14 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C536E28609 for ; Thu, 23 May 2019 22:31:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388518AbfEWWbM (ORCPT ); Thu, 23 May 2019 18:31:12 -0400 Received: from ale.deltatee.com ([207.54.116.67]:59978 "EHLO ale.deltatee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388509AbfEWWbM (ORCPT ); Thu, 23 May 2019 18:31:12 -0400 Received: from cgy1-donard.priv.deltatee.com ([172.16.1.31]) by ale.deltatee.com with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1hTwEs-00062Q-Eu; Thu, 23 May 2019 16:31:10 -0600 Received: from gunthorp by cgy1-donard.priv.deltatee.com with local (Exim 4.89) (envelope-from ) id 1hTwEq-0001SB-0u; Thu, 23 May 2019 16:31:04 -0600 From: Logan Gunthorpe To: linux-kernel@vger.kernel.org, linux-ntb@googlegroups.com, linux-pci@vger.kernel.org, iommu@lists.linux-foundation.org, linux-kselftest@vger.kernel.org, Jon Mason , Joerg Roedel Cc: Bjorn Helgaas , Allen Hubbe , Dave Jiang , Serge Semin , Eric Pilmore , Logan Gunthorpe Date: Thu, 23 May 2019 16:30:54 -0600 Message-Id: <20190523223100.5526-5-logang@deltatee.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190523223100.5526-1-logang@deltatee.com> References: <20190523223100.5526-1-logang@deltatee.com> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 172.16.1.31 X-SA-Exim-Rcpt-To: linux-ntb@googlegroups.com, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-kselftest@vger.kernel.org, jdmason@kudzu.us, joro@8bytes.org, bhelgaas@google.com, dave.jiang@intel.com, allenbh@gmail.com, fancer.lancer@gmail.com, epilmore@gigaio.com, logang@deltatee.com X-SA-Exim-Mail-From: gunthorp@deltatee.com Subject: [PATCH v5 04/10] NTB: Introduce functions to calculate multi-port resource index 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-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP When using multi-ports each port uses resources (dbs, msgs, mws, etc) on every other port. Creating a mapping for these resources such that each port has a corresponding resource on every other port is a bit tricky. Introduce the ntb_peer_resource_idx() function for this purpose. It returns the peer resource number that will correspond with the local peer index on the remote peer. Also, introduce ntb_peer_highest_mw_idx() which will use ntb_peer_resource_idx() but return the MW index starting with the highest index and working down. Signed-off-by: Logan Gunthorpe Cc: Jon Mason Cc: Dave Jiang Cc: Allen Hubbe --- include/linux/ntb.h | 70 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 70 insertions(+) diff --git a/include/linux/ntb.h b/include/linux/ntb.h index 91cf492b16a0..66552830544b 100644 --- a/include/linux/ntb.h +++ b/include/linux/ntb.h @@ -1557,4 +1557,74 @@ static inline int ntb_peer_msg_write(struct ntb_dev *ntb, int pidx, int midx, return ntb->ops->peer_msg_write(ntb, pidx, midx, msg); } +/** + * ntb_peer_resource_idx() - get a resource index for a given peer idx + * @ntb: NTB device context. + * @pidx: Peer port index. + * + * When constructing a graph of peers, each remote peer must use a different + * resource index (mw, doorbell, etc) to communicate with each other + * peer. + * + * In a two peer system, this function should always return 0 such that + * resource 0 points to the remote peer on both ports. + * + * In a 5 peer system, this function will return the following matrix + * + * pidx \ port 0 1 2 3 4 + * 0 0 0 1 2 3 + * 1 0 1 1 2 3 + * 2 0 1 2 2 3 + * 3 0 1 2 3 3 + * + * For example, if this function is used to program peer's memory + * windows, port 0 will program MW 0 on all it's peers to point to itself. + * port 1 will program MW 0 in port 0 to point to itself and MW 1 on all + * other ports. etc. + * + * For the legacy two host case, ntb_port_number() and ntb_peer_port_number() + * both return zero and therefore this function will always return zero. + * So MW 0 on each host would be programmed to point to the other host. + * + * Return: the resource index to use for that peer. + */ +static inline int ntb_peer_resource_idx(struct ntb_dev *ntb, int pidx) +{ + int local_port, peer_port; + + if (pidx >= ntb_peer_port_count(ntb)) + return -EINVAL; + + local_port = ntb_logical_port_number(ntb); + peer_port = ntb_peer_logical_port_number(ntb, pidx); + + if (peer_port < local_port) + return local_port - 1; + else + return local_port; +} + +/** + * ntb_peer_highest_mw_idx() - get a memory window index for a given peer idx + * using the highest index memory windows first + * + * @ntb: NTB device context. + * @pidx: Peer port index. + * + * Like ntb_peer_resource_idx(), except it returns indexes starting with + * last memory window index. + * + * Return: the resource index to use for that peer. + */ +static inline int ntb_peer_highest_mw_idx(struct ntb_dev *ntb, int pidx) +{ + int ret; + + ret = ntb_peer_resource_idx(ntb, pidx); + if (ret < 0) + return ret; + + return ntb_mw_count(ntb, pidx) - ret - 1; +} + #endif