From patchwork Fri Jul 22 03:40:28 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Keith Busch X-Patchwork-Id: 651495 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 3rwbyf6Klbz9t0l for ; Fri, 22 Jul 2016 13:40:42 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752847AbcGVDkb (ORCPT ); Thu, 21 Jul 2016 23:40:31 -0400 Received: from mga01.intel.com ([192.55.52.88]:17275 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752576AbcGVDka (ORCPT ); Thu, 21 Jul 2016 23:40:30 -0400 Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga101.fm.intel.com with ESMTP; 21 Jul 2016 20:40:30 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.28,402,1464678000"; d="scan'208";a="143585092" Received: from dcgshare.lm.intel.com ([10.232.118.254]) by fmsmga004.fm.intel.com with ESMTP; 21 Jul 2016 20:40:29 -0700 Received: by dcgshare.lm.intel.com (Postfix, from userid 1017) id E2374E0C6D; Thu, 21 Jul 2016 21:40:28 -0600 (MDT) From: Keith Busch To: linux-pci@vger.kernel.org Cc: Bjorn Helgaas , Keith Busch Subject: [PATCH] pci: Allow additional busses for hotplug bridges Date: Thu, 21 Jul 2016 21:40:28 -0600 Message-Id: <1469158828-4179-1-git-send-email-keith.busch@intel.com> X-Mailer: git-send-email 1.7.1 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org A user may hot add a switch requiring more than one bus to enumerate. This previously required a system reboot if BIOS did not sufficiently pad the bus resource, which they frequently don't do. This patch allows a user specify the minimum number of resources to reserve for a hotplug bridge's subordinate busses so rebooting won't be necessary. The default is 1, which is equivalent to previous behavior. Signed-off-by: Keith Busch --- Documentation/kernel-parameters.txt | 3 +++ drivers/pci/pci.c | 8 ++++++++ drivers/pci/probe.c | 9 +++++++++ include/linux/pci.h | 1 + 4 files changed, 21 insertions(+) diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 82b42c9..ce4b45b 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -3016,6 +3016,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted. hpmemsize=nn[KMG] The fixed amount of bus space which is reserved for hotplug bridge's memory window. Default size is 2 megabytes. + hpbussize=nn The minimum amount of additional bus + space which is reserved for hotplug bridge's + bus window. Default is 1. realloc= Enable/disable reallocating PCI bridge resources if allocations done by BIOS are too small to accommodate resources required by all child diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index c8b4dbd..7d290f7 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -81,6 +81,9 @@ unsigned long pci_cardbus_mem_size = DEFAULT_CARDBUS_MEM_SIZE; unsigned long pci_hotplug_io_size = DEFAULT_HOTPLUG_IO_SIZE; unsigned long pci_hotplug_mem_size = DEFAULT_HOTPLUG_MEM_SIZE; +#define DEFAULT_HOTPLUG_BUS_SIZE (1) +unsigned long pci_hotplug_bus_size = DEFAULT_HOTPLUG_BUS_SIZE; + enum pcie_bus_config_types pcie_bus_config = PCIE_BUS_DEFAULT; /* @@ -5021,6 +5024,11 @@ static int __init pci_setup(char *str) pci_hotplug_io_size = memparse(str + 9, &str); } else if (!strncmp(str, "hpmemsize=", 10)) { pci_hotplug_mem_size = memparse(str + 10, &str); + } else if (!strncmp(str, "hpbussize=", 10)) { + pci_hotplug_bus_size = + simple_strtoul(str + 10, &str, 0); + if (pci_hotplug_bus_size > 0xff) + pci_hotplug_bus_size = DEFAULT_HOTPLUG_BUS_SIZE; } else if (!strncmp(str, "pcie_bus_tune_off", 17)) { pcie_bus_config = PCIE_BUS_TUNE_OFF; } else if (!strncmp(str, "pcie_bus_safe", 13)) { diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 8e3ef72..9454396 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -2077,6 +2077,15 @@ unsigned int pci_scan_child_bus(struct pci_bus *bus) } /* + * Make sure a hot plug bridge has at least the minimum requested + * number of busses. + */ + if (bus->self && bus->self->is_hotplug_bridge && pci_hotplug_bus_size) { + if (max - bus->busn_res.start < pci_hotplug_bus_size - 1) + max = bus->busn_res.start + pci_hotplug_bus_size - 1; + } + + /* * We've scanned the bus and so we know all about what's on * the other side of any bridges that may be on this bus plus * any devices. diff --git a/include/linux/pci.h b/include/linux/pci.h index b67e4df..0c28325 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1706,6 +1706,7 @@ extern u8 pci_cache_line_size; extern unsigned long pci_hotplug_io_size; extern unsigned long pci_hotplug_mem_size; +extern unsigned long pci_hotplug_bus_size; /* Architecture-specific versions may override these (weak) */ void pcibios_disable_device(struct pci_dev *dev);