From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751956AbdFNSyh (ORCPT ); Wed, 14 Jun 2017 14:54:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:35506 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751628AbdFNSyg (ORCPT ); Wed, 14 Jun 2017 14:54:36 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D6EA6239B4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=helgaas@kernel.org Date: Wed, 14 Jun 2017 13:54:33 -0500 From: Bjorn Helgaas To: Christian =?iso-8859-1?Q?K=F6nig?= Cc: linux-pci@vger.kernel.org, dri-devel@lists.freedesktop.org, platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org Subject: Re: [PATCH v5 3/6] PCI: add functionality for resizing resources v6 Message-ID: <20170614185433.GD20778@bhelgaas-glaptop.roam.corp.google.com> References: <1496998787-6371-1-git-send-email-deathsimple@vodafone.de> <1496998787-6371-4-git-send-email-deathsimple@vodafone.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1496998787-6371-4-git-send-email-deathsimple@vodafone.de> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 09, 2017 at 10:59:44AM +0200, Christian König wrote: > From: Christian König > > This allows device drivers to request resizing their BARs. > > The function only tries to reprogram the windows of the bridge directly above > the requesting device and only the BAR of the same type (usually mem, 64bit, > prefetchable). This is done to make sure not to disturb other drivers by > changing the BARs of their devices. > > If reprogramming the bridge BAR fails the old status is restored and -ENOSPC > returned to the calling device driver. Can you include an outline of how drivers should use pci_resize_resource() here, including disabling decoding, releasing resource(s), resizing, re-enabling decoding, re-reading pdev->resource[]? > v2: rebase on changes in rbar support > v3: style cleanups, fail if memory decoding is enabled or resources > still allocated, resize all unused bridge BARs, > drop calling pci_reenable_device > v4: print resources before releasing them, style cleanups, > use pci_rbar_size_to_bytes, use PCI_RES_TYPE_MASK > v5: use next pointer to simplify loop > v6: move reassigning resources on error to driver side > > Signed-off-by: Christian König > --- > drivers/pci/setup-bus.c | 98 +++++++++++++++++++++++++++++++++++++++++++++++++ > drivers/pci/setup-res.c | 58 +++++++++++++++++++++++++++++ > include/linux/pci.h | 3 ++ > 3 files changed, 159 insertions(+) > > diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c > index 451a9c0..2ea872d 100644 > --- a/drivers/pci/setup-bus.c > +++ b/drivers/pci/setup-bus.c > @@ -1908,6 +1908,104 @@ void pci_assign_unassigned_bridge_resources(struct pci_dev *bridge) > } > EXPORT_SYMBOL_GPL(pci_assign_unassigned_bridge_resources); > > +int pci_reassign_bridge_resources(struct pci_dev *bridge, unsigned long type) > +{ > + struct pci_dev_resource *dev_res; > + struct pci_dev *next; > + LIST_HEAD(saved); > + LIST_HEAD(added); > + LIST_HEAD(failed); > + unsigned int i; > + int ret; > + > + /* Walk to the root hub, releasing bridge BARs when possible */ > + next = bridge; > + do { > + bridge = next; > + for (i = PCI_BRIDGE_RESOURCES; i < PCI_BRIDGE_RESOURCE_END; > + i++) { > + struct resource *res = &bridge->resource[i]; > + > + if ((res->flags ^ type) & PCI_RES_TYPE_MASK) > + continue; > + > + /* Ignore BARs which are still in use */ > + if (res->child) > + continue; > + > + ret = add_to_list(&saved, bridge, res, 0, 0); > + if (ret) > + goto cleanup; > + > + dev_info(&bridge->dev, "BAR %d: releasing %pR\n", > + i, res); > + > + if (res->parent) > + release_resource(res); > + res->start = 0; > + res->end = 0; > + break; > + } > + if (i == PCI_BRIDGE_RESOURCE_END) > + break; > + > + next = bridge->bus ? bridge->bus->self : NULL; > + } while (next); > + > + if (list_empty(&saved)) > + return -ENOENT; > + > + __pci_bus_size_bridges(bridge->subordinate, &added); > + __pci_bridge_assign_resources(bridge, &added, &failed); > + BUG_ON(!list_empty(&added)); > + > + if (!list_empty(&failed)) { > + ret = -ENOSPC; > + goto cleanup; > + } > + > + list_for_each_entry(dev_res, &saved, list) { > + /* Skip the bridge we just assigned resources for. */ > + if (bridge == dev_res->dev) > + continue; > + > + bridge = dev_res->dev; > + pci_setup_bridge(bridge->subordinate); > + } > + > + free_list(&saved); > + return 0; > + > +cleanup: > + /* restore size and flags */ > + list_for_each_entry(dev_res, &failed, list) { > + struct resource *res = dev_res->res; > + > + res->start = dev_res->start; > + res->end = dev_res->end; > + res->flags = dev_res->flags; > + } > + free_list(&failed); > + > + /* Revert to the old configuration */ > + list_for_each_entry(dev_res, &saved, list) { > + struct resource *res = dev_res->res; > + > + bridge = dev_res->dev; > + i = res - bridge->resource; > + > + res->start = dev_res->start; > + res->end = dev_res->end; > + res->flags = dev_res->flags; > + > + pci_claim_resource(bridge, i); > + pci_setup_bridge(bridge->subordinate); > + } > + free_list(&saved); > + > + return ret; > +} > + > void pci_assign_unassigned_bus_resources(struct pci_bus *bus) > { > struct pci_dev *dev; > diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c > index 4bc589e..077c515 100644 > --- a/drivers/pci/setup-res.c > +++ b/drivers/pci/setup-res.c > @@ -383,6 +383,64 @@ int pci_reassign_resource(struct pci_dev *dev, int resno, resource_size_t addsiz > return 0; > } > > +void pci_release_resource(struct pci_dev *dev, int resno) > +{ > + struct resource *res = dev->resource + resno; > + > + dev_info(&dev->dev, "BAR %d: releasing %pR\n", resno, res); > + release_resource(res); > + res->end = resource_size(res) - 1; > + res->start = 0; > + res->flags |= IORESOURCE_UNSET; > +} > +EXPORT_SYMBOL(pci_release_resource); > + > +int pci_resize_resource(struct pci_dev *dev, int resno, int size) > +{ > + struct resource *res = dev->resource + resno; > + int old, ret; > + u32 sizes; > + u16 cmd; > + > + /* Make sure the resource isn't assigned before resizing it. */ > + if (!(res->flags & IORESOURCE_UNSET)) > + return -EBUSY; > + > + pci_read_config_word(dev, PCI_COMMAND, &cmd); > + if (cmd & PCI_COMMAND_MEMORY) > + return -EBUSY; > + > + sizes = pci_rbar_get_possible_sizes(dev, resno); > + if (!sizes) > + return -ENOTSUPP; > + > + if (!(sizes & BIT(size))) > + return -EINVAL; > + > + old = pci_rbar_get_current_size(dev, resno); > + if (old < 0) > + return old; > + > + ret = pci_rbar_set_size(dev, resno, size); > + if (ret) > + return ret; > + > + res->end = res->start + pci_rbar_size_to_bytes(size) - 1; > + > + /* Check if the new config works by trying to assign everything. */ > + ret = pci_reassign_bridge_resources(dev->bus->self, res->flags); > + if (ret) > + goto error_resize; > + > + return 0; > + > +error_resize: > + pci_rbar_set_size(dev, resno, old); > + res->end = res->start + pci_rbar_size_to_bytes(old) - 1; > + return ret; > +} > +EXPORT_SYMBOL(pci_resize_resource); > + > int pci_enable_resources(struct pci_dev *dev, int mask) > { > u16 cmd, old_cmd; > diff --git a/include/linux/pci.h b/include/linux/pci.h > index eb3da1a..2d631ad 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -1068,6 +1068,8 @@ void pci_reset_bridge_secondary_bus(struct pci_dev *dev); > 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); > +void pci_release_resource(struct pci_dev *dev, int resno); > +int __must_check pci_resize_resource(struct pci_dev *dev, int i, int size); > int pci_select_bars(struct pci_dev *dev, unsigned long flags); > bool pci_device_is_present(struct pci_dev *pdev); > void pci_ignore_hotplug(struct pci_dev *dev); > @@ -1148,6 +1150,7 @@ void pci_assign_unassigned_resources(void); > void pci_assign_unassigned_bridge_resources(struct pci_dev *bridge); > void pci_assign_unassigned_bus_resources(struct pci_bus *bus); > void pci_assign_unassigned_root_bus_resources(struct pci_bus *bus); > +int pci_reassign_bridge_resources(struct pci_dev *bridge, unsigned long type); > void pdev_enable_device(struct pci_dev *); > int pci_enable_resources(struct pci_dev *, int mask); > void pci_fixup_irqs(u8 (*)(struct pci_dev *, u8 *), > -- > 2.7.4 >