Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752328AbaJBIMn (ORCPT ); Thu, 2 Oct 2014 04:12:43 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39385 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751017AbaJBIMj (ORCPT ); Thu, 2 Oct 2014 04:12:39 -0400 Message-ID: <1412237508.2772.20.camel@localhost.localdomain> Subject: Re: [PATCH] PCI: add kernel parameter to override devid<->driver mapping. From: Marcel Apfelbaum To: Alex Williamson Cc: linux-pci@vger.kernel.org, bhelgaas@google.com, linux-kernel@vger.kernel.org, marcel@redhat.com, mst@redhat.com Date: Thu, 02 Oct 2014 11:11:48 +0300 In-Reply-To: <1412189309.7360.238.camel@ul30vt.home> References: <1412095115-28982-1-git-send-email-marcel.a@redhat.com> <1412189309.7360.238.camel@ul30vt.home> 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 On Wed, 2014-10-01 at 12:48 -0600, Alex Williamson wrote: > On Tue, 2014-09-30 at 19:38 +0300, Marcel Apfelbaum wrote: > > Scanning a lot of devices during boot requires a lot of time. > > On other scenarios there is a need to bind a driver to a specific slot. > > > > Binding devices to pci-stub driver does not work, > > as it will not differentiate between devices of the > > same type. Using some start scripts is error prone. > > > > The solution leverages driver_override functionality introduced by > > > > commit: 782a985d7af26db39e86070d28f987cad21313c0 > > Author: Alex Williamson > > Date: Tue May 20 08:53:21 2014 -0600 > > > > PCI: Introduce new device binding path using pci_dev.driver_override > > > > In order to bind PCI slot 0001:02:03.4 to pci-stub use: > > driver[0001:02:03.4]=pci-stub > > So the option is actually: > > pci=driver=[...]=foo,driver=[...]=bar > > That's not very clear from the commit log. Hi, I will make it more clear. Thanks for the review, Marcel > > > > > Signed-off-by: Marcel Apfelbaum > > --- > > Notes: > > - For the moment only 32 slots can be assigned specific driver. > > - I have further ideas on top of this patch based on your reviews. > > I thought of: > > - Use wildcards to specify entire buses/devices, something like: > > driver[0001:02:*.*]=pci-stub > > - Use comma to separate several devices: > > driver[0001:02:03.4,0001:02:04.0,...]=pci-stub > > - Make domain optional: > > driver[00:03.0]=pci-stub > > > > Comments will be appreciated, > > Thanks, > > Marcel > > > > Documentation/kernel-parameters.txt | 4 +++ > > drivers/pci/bus.c | 1 + > > drivers/pci/pci.c | 61 +++++++++++++++++++++++++++++++++++++ > > drivers/pci/pci.h | 1 + > > 4 files changed, 67 insertions(+) > > > > diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt > > index 5ae8608..c1cbb4c 100644 > > --- a/Documentation/kernel-parameters.txt > > +++ b/Documentation/kernel-parameters.txt > > @@ -2631,6 +2631,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted. > > pcie_scan_all Scan all possible PCIe devices. Otherwise we > > only look for one device below a PCIe downstream > > port. > > + driver Provide an override to the devid<->driver mapping > > + for a specific slot. > > + Bind PCI slot 0001:02:03.4 to pci-stub by: > > + driver[0001:02:03.4]=pci-stub > > > > pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power > > Management. > > diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c > > index 73aef51..7a7ed85 100644 > > --- a/drivers/pci/bus.c > > +++ b/drivers/pci/bus.c > > @@ -245,6 +245,7 @@ void pci_bus_add_device(struct pci_dev *dev) > > * are not assigned yet for some devices. > > */ > > pci_fixup_device(pci_fixup_final, dev); > > + pci_device_setup_driver_override(dev); > > pci_create_sysfs_dev_files(dev); > > pci_proc_attach_device(dev); > > > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > > index b7678be..0a3e07c 100644 > > --- a/drivers/pci/pci.c > > +++ b/drivers/pci/pci.c > > @@ -4426,6 +4426,65 @@ void __weak pci_fixup_cardbus(struct pci_bus *bus) > > } > > EXPORT_SYMBOL(pci_fixup_cardbus); > > > > +#define DRIVER_OVERRIDE_NAME_LENGTH 64 > > +#define DRIVER_OVERRIDE_MAP_SIZE 32 > > + > > +struct driver_override_entry { > > + unsigned int domain; > > u16 > > > + unsigned char bus; > > u8 > > > + unsigned int devfn; > > u8 > > > + char driver_name[DRIVER_OVERRIDE_NAME_LENGTH]; > > +}; > > + > > +static struct driver_override_entry __initdata > > + driver_override_map[DRIVER_OVERRIDE_MAP_SIZE]; > > +static int driver_override_num_entries __initdata; > > + > > +void pci_device_setup_driver_override(struct pci_dev *dev) > > +{ > > + int i; > > + > > + for (i = 0; i < driver_override_num_entries; i++) { > > + if (pci_domain_nr(dev->bus) != driver_override_map[i].domain || > > + dev->bus->number != driver_override_map[i].bus || > > + dev->devfn != driver_override_map[i].devfn) > > + continue; > > + > > + dev->driver_override = kstrndup(driver_override_map[i].driver_name, > > + DRIVER_OVERRIDE_NAME_LENGTH, > > + GFP_KERNEL); > > + break; > > + } > > +} > > + > > +static void __init pci_parse_driver_override(char *str) > > +{ > > + unsigned int domain, bus, dev, fn; > > + char driver_name[DRIVER_OVERRIDE_NAME_LENGTH]; > > + int ret, next_entry; > > + char format[] = "[%4x:%2x:%2x.%2x]=%%%ds"; > > + > > + sprintf(format + 18, "%%%ds", DRIVER_OVERRIDE_NAME_LENGTH); > > There must be a less confusing way to do this. > > > + ret = sscanf(str, format, &domain, &bus, &dev, &fn, driver_name); > > + > > + if (ret != 5) { > > + pr_err("PCI: Invalid command line: driver%s\n", str); > > + return; > > + } > > + > > + if (driver_override_num_entries == DRIVER_OVERRIDE_MAP_SIZE) { > > + pr_err("PCI: Driver map overflow - ignoring driver%s\n", str); > > + return; > > + } > > + > > + next_entry = driver_override_num_entries++; > > + driver_override_map[next_entry].domain = domain; > > + driver_override_map[next_entry].bus = bus && 0xff; > > How could it not be given our format? > > > + driver_override_map[next_entry].devfn = ((dev & 0x1f) << 3) | (fn & 0x7); > > PCI_DEVFN(dev, fn) > > > + memcpy(driver_override_map[next_entry].driver_name, > > + driver_name, sizeof(driver_name)); > > +} > > + > > static int __init pci_setup(char *str) > > { > > while (str) { > > @@ -4468,6 +4527,8 @@ static int __init pci_setup(char *str) > > pcie_bus_config = PCIE_BUS_PEER2PEER; > > } else if (!strncmp(str, "pcie_scan_all", 13)) { > > pci_add_flags(PCI_SCAN_ALL_PCIE_DEVS); > > + } else if (!strncmp(str, "driver", 6)) { > > + pci_parse_driver_override(str + 6); > > } else { > > printk(KERN_ERR "PCI: Unknown option `%s'\n", > > str); > > diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h > > index 0601890..023d78b 100644 > > --- a/drivers/pci/pci.h > > +++ b/drivers/pci/pci.h > > @@ -197,6 +197,7 @@ enum pci_bar_type { > > bool pci_bus_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *pl, > > int crs_timeout); > > int pci_setup_device(struct pci_dev *dev); > > +void pci_device_setup_driver_override(struct pci_dev *dev); > > int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type, > > struct resource *res, unsigned int reg); > > int pci_resource_bar(struct pci_dev *dev, int resno, enum pci_bar_type *type); > > > -- 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/