From patchwork Fri Mar 27 21:16:15 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ashok Raj X-Patchwork-Id: 11463125 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 30E8015AB for ; Fri, 27 Mar 2020 21:16:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 067E3206F1 for ; Fri, 27 Mar 2020 21:16:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727505AbgC0VQT (ORCPT ); Fri, 27 Mar 2020 17:16:19 -0400 Received: from mga17.intel.com ([192.55.52.151]:7152 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727495AbgC0VQT (ORCPT ); Fri, 27 Mar 2020 17:16:19 -0400 IronPort-SDR: g+lgqZGcwJ6k9p0wm5HVYOdx96f4e41rmUbciPgegZmRw78Z/h16vbxxW/1OGU7Gw7ZvytOpq6 U/R4TaSEL73g== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Mar 2020 14:16:19 -0700 IronPort-SDR: rV7hqmr13pWJuQkiYhYbSJXKKHrwVG0cAM+xP1wWQgv8sVrOS6I1VcXCqR+FEJ6aezxiHIIFZq bKkm1znzny2w== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.72,313,1580803200"; d="scan'208";a="282971379" Received: from otc-nc-03.jf.intel.com ([10.54.39.25]) by fmsmga002.fm.intel.com with ESMTP; 27 Mar 2020 14:16:18 -0700 From: Ashok Raj To: linux-pci@vger.kernel.org, Bjorn Helgaas Cc: Ashok Raj , linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH] pci: Fixes MaxPayloadSize (MPS) programming for RCiEP devices. Date: Fri, 27 Mar 2020 14:16:15 -0700 Message-Id: <1585343775-4019-1-git-send-email-ashok.raj@intel.com> X-Mailer: git-send-email 2.7.4 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Root Complex Integrated devices (RCiEP) do not have a Root Port before the device. pci_configure_mps() should simply stick the max value for MaxPayload size in Device Control, and for MaxReadReq. Unless pcie=pcie_bus-peer2peer is used in kernel commandline PCIE_BUS_PEER2PEER. When MPS is configured lower, it could result in reduced performance. Fixes: 9dae3a97297f ("PCI: Move MPS configuration check to pci_configure_device()") Signed-off-by: Ashok Raj Tested-by: Dave Jiang To: Bjorn Helgaas To: linux-pci@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org Cc: Ashok Raj --- drivers/pci/probe.c | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-) diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index eeff8a07..a738b1c 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -1895,13 +1895,34 @@ static void pci_configure_mps(struct pci_dev *dev) struct pci_dev *bridge = pci_upstream_bridge(dev); int mps, mpss, p_mps, rc; - if (!pci_is_pcie(dev) || !bridge || !pci_is_pcie(bridge)) + if (!pci_is_pcie(dev)) return; /* MPS and MRRS fields are of type 'RsvdP' for VFs, short-circuit out */ if (dev->is_virtfn) return; + /* + * If this is a Root Complex Integrated Endpoint + * Simply program the max value from DEVCAP. No additional + * Lookup is necessary + */ + if (pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END) { + if (pcie_bus_config == PCIE_BUS_PEER2PEER) + mps = 128; + else + mps = 128 << dev->pcie_mpss; + rc = pcie_set_mps(dev, mps); + if (rc) { + pci_warn(dev, "can't set Max Payload Size to %d; if necessary, use \"pci=pcie_bus_safe\" and report a bug\n", + mps); + return; + } + } + + if (!bridge || !pci_is_pcie(bridge)) + return; + mps = pcie_get_mps(dev); p_mps = pcie_get_mps(bridge);