From patchwork Thu May 3 20:00:29 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bjorn Helgaas X-Patchwork-Id: 10379103 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.web.codeaurora.org (Postfix) with ESMTP id 5A47D60541 for ; Thu, 3 May 2018 20:01:27 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4CF6729258 for ; Thu, 3 May 2018 20:01:27 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 416E829273; Thu, 3 May 2018 20:01:27 +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=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=unavailable 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 D6FF329270 for ; Thu, 3 May 2018 20:01:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751412AbeECUAe (ORCPT ); Thu, 3 May 2018 16:00:34 -0400 Received: from mail.kernel.org ([198.145.29.99]:33930 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750823AbeECUAb (ORCPT ); Thu, 3 May 2018 16:00:31 -0400 Received: from localhost (unknown [69.71.5.252]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 88E0C21770; Thu, 3 May 2018 20:00:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1525377630; bh=rxbT8xj45/G27iJfQAW7k6bYjYqHwN6SXYBodfuT/1o=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=0b7BaW4gl9gDOq6V06D+q7DEndb44y3lZIhMrvhQ3e/c9yErqyUIAnA28lUZdKuag 1+XQyAGk3F8xmvO51c7UzGGDikrjP1/uBxslnsHdsKjQjfJ8Pqqi6cOEDh/Mw4EUDF lJ3gryDRPQTAiEBJGkt8f+QKcFEb4jcd9wZrNcjA= Subject: [PATCH v6 3/5] cxgb4: Report PCIe link properties with pcie_print_link_status() From: Bjorn Helgaas To: Jeff Kirsher , Ganesh Goudar , Michael Chan , Ariel Elior Cc: linux-pci@vger.kernel.org, everest-linux-l2@cavium.com, intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Tal Gilboa , Tariq Toukan , Jacob Keller , Jakub Kicinski Date: Thu, 03 May 2018 15:00:29 -0500 Message-ID: <152537762921.62474.3606947168382589745.stgit@bhelgaas-glaptop.roam.corp.google.com> In-Reply-To: <152537719056.62474.2571390812509425478.stgit@bhelgaas-glaptop.roam.corp.google.com> References: <152537719056.62474.2571390812509425478.stgit@bhelgaas-glaptop.roam.corp.google.com> User-Agent: StGit/0.18 MIME-Version: 1.0 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 From: Bjorn Helgaas Previously the driver used pcie_get_minimum_link() to warn when the NIC is in a slot that can't supply as much bandwidth as the NIC could use. pcie_get_minimum_link() can be misleading because it finds the slowest link and the narrowest link (which may be different links) without considering the total bandwidth of each link. For a path with a 16 GT/s x1 link and a 2.5 GT/s x16 link, it returns 2.5 GT/s x1, which corresponds to 250 MB/s of bandwidth, not the true available bandwidth of about 1969 MB/s for a 16 GT/s x1 link. Use pcie_print_link_status() to report PCIe link speed and possible limitations instead of implementing this in the driver itself. This finds the slowest link in the path to the device by computing the total bandwidth of each link and compares that with the capabilities of the device. The dmesg change is: - PCIe link speed is %s, device supports %s - PCIe link width is x%d, device supports x%d + %u.%03u Gb/s available PCIe bandwidth (%s x%d link) or, if the device is capable of better performance than is available in the current slot: - A slot with more lanes and/or higher speed is suggested for optimal performance. + %u.%03u Gb/s available PCIe bandwidth, limited by %s x%d link at %s (capable of %u.%03u Gb/s with %s x%d link) Signed-off-by: Bjorn Helgaas --- drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c | 75 ----------------------- 1 file changed, 1 insertion(+), 74 deletions(-) diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c index 24d2865b8806..7328f24ba1dd 100644 --- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c +++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c @@ -5042,79 +5042,6 @@ static int init_rss(struct adapter *adap) return 0; } -static int cxgb4_get_pcie_dev_link_caps(struct adapter *adap, - enum pci_bus_speed *speed, - enum pcie_link_width *width) -{ - u32 lnkcap1, lnkcap2; - int err1, err2; - -#define PCIE_MLW_CAP_SHIFT 4 /* start of MLW mask in link capabilities */ - - *speed = PCI_SPEED_UNKNOWN; - *width = PCIE_LNK_WIDTH_UNKNOWN; - - err1 = pcie_capability_read_dword(adap->pdev, PCI_EXP_LNKCAP, - &lnkcap1); - err2 = pcie_capability_read_dword(adap->pdev, PCI_EXP_LNKCAP2, - &lnkcap2); - if (!err2 && lnkcap2) { /* PCIe r3.0-compliant */ - if (lnkcap2 & PCI_EXP_LNKCAP2_SLS_8_0GB) - *speed = PCIE_SPEED_8_0GT; - else if (lnkcap2 & PCI_EXP_LNKCAP2_SLS_5_0GB) - *speed = PCIE_SPEED_5_0GT; - else if (lnkcap2 & PCI_EXP_LNKCAP2_SLS_2_5GB) - *speed = PCIE_SPEED_2_5GT; - } - if (!err1) { - *width = (lnkcap1 & PCI_EXP_LNKCAP_MLW) >> PCIE_MLW_CAP_SHIFT; - if (!lnkcap2) { /* pre-r3.0 */ - if (lnkcap1 & PCI_EXP_LNKCAP_SLS_5_0GB) - *speed = PCIE_SPEED_5_0GT; - else if (lnkcap1 & PCI_EXP_LNKCAP_SLS_2_5GB) - *speed = PCIE_SPEED_2_5GT; - } - } - - if (*speed == PCI_SPEED_UNKNOWN || *width == PCIE_LNK_WIDTH_UNKNOWN) - return err1 ? err1 : err2 ? err2 : -EINVAL; - return 0; -} - -static void cxgb4_check_pcie_caps(struct adapter *adap) -{ - enum pcie_link_width width, width_cap; - enum pci_bus_speed speed, speed_cap; - -#define PCIE_SPEED_STR(speed) \ - (speed == PCIE_SPEED_8_0GT ? "8.0GT/s" : \ - speed == PCIE_SPEED_5_0GT ? "5.0GT/s" : \ - speed == PCIE_SPEED_2_5GT ? "2.5GT/s" : \ - "Unknown") - - if (cxgb4_get_pcie_dev_link_caps(adap, &speed_cap, &width_cap)) { - dev_warn(adap->pdev_dev, - "Unable to determine PCIe device BW capabilities\n"); - return; - } - - if (pcie_get_minimum_link(adap->pdev, &speed, &width) || - speed == PCI_SPEED_UNKNOWN || width == PCIE_LNK_WIDTH_UNKNOWN) { - dev_warn(adap->pdev_dev, - "Unable to determine PCI Express bandwidth.\n"); - return; - } - - dev_info(adap->pdev_dev, "PCIe link speed is %s, device supports %s\n", - PCIE_SPEED_STR(speed), PCIE_SPEED_STR(speed_cap)); - dev_info(adap->pdev_dev, "PCIe link width is x%d, device supports x%d\n", - width, width_cap); - if (speed < speed_cap || width < width_cap) - dev_info(adap->pdev_dev, - "A slot with more lanes and/or higher speed is " - "suggested for optimal performance.\n"); -} - /* Dump basic information about the adapter */ static void print_adapter_info(struct adapter *adapter) { @@ -5750,7 +5677,7 @@ static int init_one(struct pci_dev *pdev, const struct pci_device_id *ent) } /* check for PCI Express bandwidth capabiltites */ - cxgb4_check_pcie_caps(adapter); + pcie_print_link_status(pdev); err = init_rss(adapter); if (err)