From patchwork Tue Apr 7 01:33:31 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu Zhao X-Patchwork-Id: 16705 Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by demeter.kernel.org (8.14.2/8.14.2) with ESMTP id n371WW33001094 for ; Tue, 7 Apr 2009 01:32:33 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754313AbZDGBc1 (ORCPT ); Mon, 6 Apr 2009 21:32:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752530AbZDGBc0 (ORCPT ); Mon, 6 Apr 2009 21:32:26 -0400 Received: from mga09.intel.com ([134.134.136.24]:61176 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753639AbZDGBcY (ORCPT ); Mon, 6 Apr 2009 21:32:24 -0400 Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga102.jf.intel.com with ESMTP; 06 Apr 2009 18:23:34 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.39,333,1235980800"; d="scan'208";a="400902710" Received: from yzhao-otc.sh.intel.com ([10.239.48.165]) by orsmga002.jf.intel.com with ESMTP; 06 Apr 2009 18:40:34 -0700 From: Yu Zhao To: linux-pci@vger.kernel.org Cc: kvm@vger.kernel.org, matthew@wil.cx, Yu Zhao Subject: [RFC PATCH 3/3] PCI: support Secondary Bus Reset Date: Tue, 7 Apr 2009 09:33:31 +0800 Message-Id: <1239068011-15164-3-git-send-email-yu.zhao@intel.com> X-Mailer: git-send-email 1.6.1 In-Reply-To: <1239068011-15164-1-git-send-email-yu.zhao@intel.com> References: <1239068011-15164-1-git-send-email-yu.zhao@intel.com> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org PCI-to-PCI Bridge 1.2 specifies that the Secondary Bus Reset bit can force the assertion of RST# on the secondary interface, which can be used to reset all devices including subordinates under this bus. This can be used to reset a function if this function is the only device under this bus. Signed-off-by: Yu Zhao --- drivers/pci/pci.c | 31 +++++++++++++++++++++++++++++++ 1 files changed, 31 insertions(+), 0 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index e459a0b..a77c33a 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -2115,6 +2115,33 @@ static int pci_pm_flr(struct pci_dev *dev, int probe) return 0; } +static int pci_secondary_bus_reset(struct pci_dev *dev, int probe) +{ + u16 ctrl; + struct pci_dev *pdev; + + if (dev->subordinate) + return -ENOTTY; + + list_for_each_entry(pdev, &dev->bus->devices, bus_list) + if (pdev != dev) + return -ENOTTY; + + if (probe) + return 0; + + pci_read_config_word(dev->bus->self, PCI_BRIDGE_CONTROL, &ctrl); + ctrl |= PCI_BRIDGE_CTL_BUS_RESET; + pci_write_config_word(dev->bus->self, PCI_BRIDGE_CONTROL, ctrl); + msleep(100); + + ctrl &= ~PCI_BRIDGE_CTL_BUS_RESET; + pci_write_config_word(dev->bus->self, PCI_BRIDGE_CONTROL, ctrl); + msleep(100); + + return 0; +} + static int pci_dev_reset(struct pci_dev *dev, int probe) { int rc; @@ -2136,6 +2163,10 @@ static int pci_dev_reset(struct pci_dev *dev, int probe) goto done; rc = pci_pm_flr(dev, probe); + if (rc != -ENOTTY) + goto done; + + rc = pci_secondary_bus_reset(dev, probe); done: up(&dev->dev.sem);