From patchwork Thu Aug 15 02:18:55 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yijing Wang X-Patchwork-Id: 267301 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 25B022C020B for ; Thu, 15 Aug 2013 12:19:23 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758526Ab3HOCTW (ORCPT ); Wed, 14 Aug 2013 22:19:22 -0400 Received: from szxga01-in.huawei.com ([119.145.14.64]:34659 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759963Ab3HOCTW (ORCPT ); Wed, 14 Aug 2013 22:19:22 -0400 Received: from 172.24.2.119 (EHLO szxeml207-edg.china.huawei.com) ([172.24.2.119]) by szxrg01-dlp.huawei.com (MOS 4.3.4-GA FastPath queued) with ESMTP id BGQ36879; Thu, 15 Aug 2013 10:19:14 +0800 (CST) Received: from SZXEML457-HUB.china.huawei.com (10.82.67.200) by szxeml207-edg.china.huawei.com (172.24.2.56) with Microsoft SMTP Server (TLS) id 14.1.323.7; Thu, 15 Aug 2013 10:19:12 +0800 Received: from localhost (10.135.76.69) by szxeml457-hub.china.huawei.com (10.82.67.200) with Microsoft SMTP Server id 14.1.323.7; Thu, 15 Aug 2013 10:19:08 +0800 From: Yijing Wang To: Bjorn Helgaas CC: Jon Mason , , Hanjun Guo , , Yijing Wang , Subject: [PATCH v5 2/2] PCI: update device mps when doing pci hotplug Date: Thu, 15 Aug 2013 10:18:55 +0800 Message-ID: <1376533135-36708-3-git-send-email-wangyijing@huawei.com> X-Mailer: git-send-email 1.7.11.msysgit.1 In-Reply-To: <1376533135-36708-1-git-send-email-wangyijing@huawei.com> References: <1376533135-36708-1-git-send-email-wangyijing@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.135.76.69] X-CFilter-Loop: Reflected Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Currently we don't update device's mps value when doing pci device hot-add. The hot-added device's mps will be set to default value (128B). But the upstream port device's mps may be larger than 128B which was set by firmware during system bootup. In this case the new added device may not work normally. This patch try to update the hot added device mps equal to its parent mps, if device mpss < parent mps, print warning. References: https://bugzilla.kernel.org/show_bug.cgi?id=60671 Reported-by: Yijing Wang Signed-off-by: Yijing Wang Cc: Jon Mason Cc: stable@vger.kernel.org # 3.4+ --- drivers/pci/probe.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++++- 1 files changed, 48 insertions(+), 1 deletions(-) diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 0699ec0..9419745 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -1621,6 +1621,44 @@ static int pcie_bus_configure_set(struct pci_dev *dev, void *data) return 0; } +static int pcie_bus_update_set(struct pci_dev *dev, void *data) +{ + int mps, p_mps, mpss; + struct pci_dev *parent; + + if (!pci_is_pcie(dev) || !dev->bus->self) + return 0; + + parent = dev->bus->self; + mps = pcie_get_mps(dev); + p_mps = pcie_get_mps(dev->bus->self); + + if (mps >= p_mps) + return 0; + + /* we only update the device mps, unless its parent device is root port, + * and it is the only slot directly connected to root port. + */ + mpss = 128 << dev->pcie_mpss; + if (mpss >= p_mps) { + pcie_write_mps(dev, p_mps); + } else if (pci_pcie_type(parent) == PCI_EXP_TYPE_ROOT_PORT && + pci_only_one_slot(dev->bus)) { + pcie_write_mps(parent, mpss); + pcie_write_mps(dev, mpss); + } else + dev_warn(&dev->dev, "MPS %d MPSS %d both smaller than upstream MPS %d\n" + "If necessary, use \"pci=pcie_bus_peer2peer\" boot parameter to avoid this problem\n", + mps, 128 << dev->pcie_mpss, p_mps); + return 0; +} + +static void pcie_bus_update_setting(struct pci_bus *bus) +{ + if (bus->self->is_hotplug_bridge) + pci_walk_bus(bus, pcie_bus_update_set, NULL); +} + /* pcie_bus_configure_settings requires that pci_walk_bus work in a top-down, * parents then children fashion. If this changes, then this code will not * work as designed. @@ -1632,8 +1670,17 @@ void pcie_bus_configure_settings(struct pci_bus *bus, u8 mpss) if (!pci_is_pcie(bus->self)) return; - if (pcie_bus_config == PCIE_BUS_TUNE_OFF) + if (pcie_bus_config == PCIE_BUS_TUNE_OFF) { + /* Sometimes we should update device mps here, + * eg. after hot add, device mps value will be + * set to default(128B), but the upstream port + * mps value may be larger than 128B, if we do + * not update the device mps, it maybe can not + * work normally. + */ + pcie_bus_update_setting(bus); return; + } /* FIXME - Peer to peer DMA is possible, though the endpoint would need * to be aware to the MPS of the destination. To work around this,