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Wed, 27 Mar 2019 07:41:06 +1100 (AEDT) Received: from localhost (unknown [69.71.4.100]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 56C5B2075C; Tue, 26 Mar 2019 20:41:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553632864; bh=I2l7VHpOPgfGiJFQQzefHnoJDRPgAWIk8+B9NUWmLXQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=OaKcmmXLybzj07aDasjdD5d+Oc0vSutS9jzYKiImrZ9MBxuTtM1ydxiOxOOs/14Zc EjZASs6XMMyUImZjDbMwauNZjh4wCvnPWwK8OBDKA0Y2QJ+rY6fI4UM6+Ji/P9mnU4 nIitKGuaUa7DfPmTQ2hFsln2lEGeI0tL1L1w4LS0= Date: Tue, 26 Mar 2019 15:41:02 -0500 From: Bjorn Helgaas To: Sergey Miroshnichenko Subject: Re: [PATCH RFC v4 11/21] PCI: Release and reassign the root bridge resources during rescan Message-ID: <20190326204102.GS24180@google.com> References: <20190311133122.11417-1-s.miroshnichenko@yadro.com> <20190311133122.11417-12-s.miroshnichenko@yadro.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190311133122.11417-12-s.miroshnichenko@yadro.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-pci@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux@yadro.com Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Mon, Mar 11, 2019 at 04:31:12PM +0300, Sergey Miroshnichenko wrote: > When the movable BARs feature is enabled, don't rely on the memory gaps > reserved by the BIOS/bootloader/firmware, but instead rearrange the BARs > and bridge windows starting from the root. > > Endpoint device's BARs, after being released, are resorted and written > back by the pci_assign_unassigned_root_bus_resources(). > > The last step of writing the recalculated windows to the bridges is done > by the new pci_setup_bridges() function. > > Signed-off-by: Sergey Miroshnichenko > --- > drivers/pci/pci.h | 1 + > drivers/pci/probe.c | 22 ++++++++++++++++++++++ > drivers/pci/setup-bus.c | 11 ++++++++++- > 3 files changed, 33 insertions(+), 1 deletion(-) > > diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h > index 224d88634115..e06e8692a7b1 100644 > --- a/drivers/pci/pci.h > +++ b/drivers/pci/pci.h > @@ -248,6 +248,7 @@ void __pci_bus_assign_resources(const struct pci_bus *bus, > struct list_head *realloc_head, > struct list_head *fail_head); > bool pci_bus_clip_resource(struct pci_dev *dev, int idx); > +void pci_bus_release_root_bridge_resources(struct pci_bus *bus); > > void pci_reassigndev_resource_alignment(struct pci_dev *dev); > void pci_disable_bridge_window(struct pci_dev *dev); > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > index 1cf6ec960236..692752c71f71 100644 > --- a/drivers/pci/probe.c > +++ b/drivers/pci/probe.c > @@ -3299,6 +3299,25 @@ static void pci_bus_rescan_done(struct pci_bus *bus) > pm_runtime_put(&bus->dev); > } > > +static void pci_setup_bridges(struct pci_bus *bus) > +{ > + struct pci_dev *dev; > + > + list_for_each_entry(dev, &bus->devices, bus_list) { > + struct pci_bus *child; > + > + if (!pci_dev_is_added(dev) || pci_dev_is_ignored(dev)) > + continue; > + > + child = dev->subordinate; > + if (child) > + pci_setup_bridges(child); > + } > + > + if (bus->self) > + pci_setup_bridge(bus); > +} > + > /** > * pci_rescan_bus - Scan a PCI bus for devices > * @bus: PCI bus to scan > @@ -3321,8 +3340,11 @@ unsigned int pci_rescan_bus(struct pci_bus *bus) > pci_bus_rescan_prepare(root); > > max = pci_scan_child_bus(root); > + > + pci_bus_release_root_bridge_resources(root); > pci_assign_unassigned_root_bus_resources(root); > > + pci_setup_bridges(root); > pci_bus_rescan_done(root); > } else { > max = pci_scan_child_bus(bus); > diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c > index be7d4e6d7b65..36a1907d9509 100644 > --- a/drivers/pci/setup-bus.c > +++ b/drivers/pci/setup-bus.c > @@ -1584,7 +1584,7 @@ static void pci_bridge_release_resources(struct pci_bus *bus, > pci_printk(KERN_DEBUG, dev, "resource %d %pR released\n", > PCI_BRIDGE_RESOURCES + idx, r); > /* keep the old size */ > - r->end = resource_size(r) - 1; > + r->end = pci_movable_bars_enabled() ? 0 : (resource_size(r) - 1); Doesn't this mean we're throwing away the information about the BAR size, and we'll have to size the BAR again somewhere? I would like to avoid that. But I don't know yet where you rely on this, so maybe it's not possible to avoid it. > r->start = 0; > r->flags = 0; > > @@ -1637,6 +1637,15 @@ static void pci_bus_release_bridge_resources(struct pci_bus *bus, > pci_bridge_release_resources(bus, type); > } > > +void pci_bus_release_root_bridge_resources(struct pci_bus *root_bus) > +{ > + pci_bus_release_bridge_resources(root_bus, IORESOURCE_IO, whole_subtree); > + pci_bus_release_bridge_resources(root_bus, IORESOURCE_MEM, whole_subtree); > + pci_bus_release_bridge_resources(root_bus, > + IORESOURCE_MEM_64 | IORESOURCE_PREFETCH, > + whole_subtree); > +} > + > static void pci_bus_dump_res(struct pci_bus *bus) > { > struct resource *res; > -- > 2.20.1 >