Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754055Ab3EHTar (ORCPT ); Wed, 8 May 2013 15:30:47 -0400 Received: from mx1.redhat.com ([209.132.183.28]:11522 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752731Ab3EHTaq (ORCPT ); Wed, 8 May 2013 15:30:46 -0400 Message-ID: <1368041414.7331.46.camel@ul30vt.home> Subject: Re: [PATCH v2 1/8] pci: Create pci_reset_bridge_secondary_bus() From: Alex Williamson To: Don Dutile Cc: bhelgaas@google.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Date: Wed, 08 May 2013 13:30:14 -0600 In-Reply-To: <518AA420.5020900@redhat.com> References: <20130508025339.30771.61937.stgit@bling.home> <20130508025740.30771.50033.stgit@bling.home> <518AA420.5020900@redhat.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4272 Lines: 108 On Wed, 2013-05-08 at 15:14 -0400, Don Dutile wrote: > On 05/07/2013 10:57 PM, Alex Williamson wrote: > > Move the secondary bus reset code from pci_parent_bus_reset() into its own > > function. Export it as we'll later be calling it from hotplug controllers. > > > > Signed-off-by: Alex Williamson > > --- > > drivers/pci/pci.c | 32 +++++++++++++++++++++++--------- > > include/linux/pci.h | 1 + > > 2 files changed, 24 insertions(+), 9 deletions(-) > > > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > > index b099e00..d0f313f 100644 > > --- a/drivers/pci/pci.c > > +++ b/drivers/pci/pci.c > > @@ -3210,9 +3210,30 @@ static int pci_pm_reset(struct pci_dev *dev, int probe) > > return 0; > > } > > > > -static int pci_parent_bus_reset(struct pci_dev *dev, int probe) > > +/** > > + * pci_reset_bridge_secondary_bus - Reset the secondary bus on a PCI bridge. > > + * @dev: Bridge device > > + * > > + * Use the bridge control register to assert reset on the secondary bus. > > + * Devices on the secondary bus are left in power-on state. > > + */ > > +void pci_reset_bridge_secondary_bus(struct pci_dev *dev) > see recommended api change below... > > > { > > u16 ctrl; > > + > > + pci_read_config_word(dev, PCI_BRIDGE_CONTROL,&ctrl); > > + ctrl |= PCI_BRIDGE_CTL_BUS_RESET; > > + pci_write_config_word(dev, PCI_BRIDGE_CONTROL, ctrl); > > + msleep(100); > > + > > + ctrl&= ~PCI_BRIDGE_CTL_BUS_RESET; > > + pci_write_config_word(dev, PCI_BRIDGE_CONTROL, ctrl); > > + msleep(100); > > +} > > +EXPORT_SYMBOL_GPL(pci_reset_bridge_secondary_bus); > > + > > +static int pci_parent_bus_reset(struct pci_dev *dev, int probe) > > +{ > > struct pci_dev *pdev; > > > > if (pci_is_root_bus(dev->bus) || dev->subordinate || !dev->bus->self) > > @@ -3225,14 +3246,7 @@ static int pci_parent_bus_reset(struct pci_dev *dev, int probe) > > 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); > > + pci_reset_bridge_secondary_bus(dev->bus->self); > > > It makes more sense to pass the pci-bus struct of the bus you want to reset, > instead of the pdev of the bridge that bus is sourced by. > i.e, dev->bus, and above, extract the pdev from the bus-struct. > That way, devices asking for bus-reset, don't have to know the bus-struct details > to make the call right... just their own pdev->bus reference. > (more object-like/clean). Have you read patch 7/8 or does this comment take that patch into account? For the bus reset and slot reset interfaces the API I'm proposing does require passing a pci_bus and pci_slot respectively. Here we have a bridge (pci_dev) and we want to reset the secondary bus on that bridge and I think the function name indicates that. Thanks, Alex > > return 0; > > } > > diff --git a/include/linux/pci.h b/include/linux/pci.h > > index 710067f..695620c 100644 > > --- a/include/linux/pci.h > > +++ b/include/linux/pci.h > > @@ -905,6 +905,7 @@ int pcie_set_mps(struct pci_dev *dev, int mps); > > int __pci_reset_function(struct pci_dev *dev); > > int __pci_reset_function_locked(struct pci_dev *dev); > > int pci_reset_function(struct pci_dev *dev); > > +void pci_reset_bridge_secondary_bus(struct pci_dev *dev); > and final tweak. > > > void pci_update_resource(struct pci_dev *dev, int resno); > > int __must_check pci_assign_resource(struct pci_dev *dev, int i); > > int __must_check pci_reassign_resource(struct pci_dev *dev, int i, resource_size_t add_size, resource_size_t align); > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/