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 <alex.william...@redhat.com>
> > 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 Alex,
I am sorry, but I missed the bellow comments, I am going to
fix them for the next version.
> > +
> > +struct driver_override_entry {
> > + unsigned int domain;
>
> u16
Sure
>
> > + unsigned char bus;
>
> u8
Sure
>
> > + unsigned int devfn;
>
> u8
Sure
>
> > + char driver_name[DRIVER_OVERRIDE_NAME_LENGTH];
I'll allocate it dynamically
> > +};
> > +
> > +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.
I'll try it, and also I'll get rid of DRIVER_OVERRIDE_NAME_LENGTH
restriction.
>
> > + 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?
Right, I'll remove the check.
>
> > + driver_override_map[next_entry].devfn = ((dev & 0x1f) << 3) | (fn &
> > 0x7);
>
> PCI_DEVFN(dev, fn)
Sure,
Thank you for the review,
Marcel
>
> > + 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);
>
>
>
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