lkml.org 
[lkml]   [2009]   [Jan]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 2/3] PCI: Add ability to rescan PCI busses
    Date
    This adds a bus attribute named "scan" to the PCI bus, which will
    appear in sysfs at "/sys/bus/pci/scan". Writing to this file will
    trigger a rescan of all PCI busses.

    To do this pci_scan_single_device() is modified to first check if the
    device to be scanned is already known to Linux. In which case it just
    returns the existing device. The old behavior was to create a new
    device anyway that would conflict with the existing one, causing all
    manner of Bad Things to happen.

    pci_scan_slot() has been rewritten to be less complex and will now
    return the number of *new* devices found. It didn't used to work to
    call pci_scan_slot() on a previously scanned slot, so returning all
    devices found was effectivly the same as returning new devices.
    ---
    drivers/pci/pci-driver.c | 1 +
    drivers/pci/pci-sysfs.c | 14 +++++++++++
    drivers/pci/pci.h | 6 +++++
    drivers/pci/probe.c | 55 +++++++++++++++++++++++++++------------------
    4 files changed, 54 insertions(+), 22 deletions(-)

    diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
    index 2bec651..fcfd445 100644
    --- a/drivers/pci/pci-driver.c
    +++ b/drivers/pci/pci-driver.c
    @@ -847,6 +847,7 @@ struct bus_type pci_bus_type = {
    .remove = pci_device_remove,
    .shutdown = pci_device_shutdown,
    .dev_attrs = pci_dev_attrs,
    + .bus_attrs = pci_bus_attrs,
    .pm = PCI_PM_OPS_PTR,
    };

    diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
    index d422f37..0781ab7 100644
    --- a/drivers/pci/pci-sysfs.c
    +++ b/drivers/pci/pci-sysfs.c
    @@ -266,6 +266,20 @@ struct device_attribute pci_dev_attrs[] = {
    __ATTR_NULL,
    };

    +#ifdef CONFIG_HOTPLUG
    +static ssize_t __ref scan(struct bus_type *type, const char *buf, size_t count)
    +{
    + pci_rescan_busses();
    +
    + return count;
    +}
    +
    +struct bus_attribute pci_bus_attrs[] = {
    + __ATTR(scan, S_IWUSR, NULL, scan),
    + __ATTR_NULL
    +};
    +#endif
    +
    static ssize_t
    pci_read_config(struct kobject *kobj, struct bin_attribute *bin_attr,
    char *buf, loff_t off, size_t count)
    diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
    index 65deed8..49d7bb4 100644
    --- a/drivers/pci/pci.h
    +++ b/drivers/pci/pci.h
    @@ -87,6 +87,7 @@ static inline int pci_proc_detach_bus(struct pci_bus *bus) { return 0; }

    /* Functions for PCI Hotplug drivers to use */
    extern unsigned int pci_do_scan_bus(struct pci_bus *bus);
    +extern void pci_rescan_busses(void) __devinit;

    #ifdef HAVE_PCI_LEGACY
    extern void pci_create_legacy_files(struct pci_bus *bus);
    @@ -128,6 +129,11 @@ extern int pcie_mch_quirk;
    extern struct device_attribute pci_dev_attrs[];
    extern struct device_attribute dev_attr_cpuaffinity;
    extern struct device_attribute dev_attr_cpulistaffinity;
    +#ifdef CONFIG_HOTPLUG
    +extern struct bus_attribute pci_bus_attrs[];
    +#else
    +#define pci_bus_attrs NULL
    +#endif

    /**
    * pci_match_one_device - Tell if a PCI device structure has a matching
    diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
    index 251c2b1..6e6172d 100644
    --- a/drivers/pci/probe.c
    +++ b/drivers/pci/probe.c
    @@ -1006,6 +1006,13 @@ struct pci_dev *__ref pci_scan_single_device(struct pci_bus *bus, int devfn)
    {
    struct pci_dev *dev;

    + /* Check to see if the device is already known */
    + dev = pci_get_slot(bus, devfn);
    + if (dev) {
    + pci_dev_put(dev);
    + return dev;
    + }
    +
    dev = pci_scan_device(bus, devfn);
    if (!dev)
    return NULL;
    @@ -1024,35 +1031,26 @@ EXPORT_SYMBOL(pci_scan_single_device);
    * Scan a PCI slot on the specified PCI bus for devices, adding
    * discovered devices to the @bus->devices list. New devices
    * will not have is_added set.
    + *
    + * Returns the number of new devices found.
    */
    int pci_scan_slot(struct pci_bus *bus, int devfn)
    {
    - int func, nr = 0;
    - int scan_all_fns;
    -
    - scan_all_fns = pcibios_scan_all_fns(bus, devfn);
    -
    - for (func = 0; func < 8; func++, devfn++) {
    - struct pci_dev *dev;
    + int fn, nr = 0;
    + struct pci_dev *dev;

    - dev = pci_scan_single_device(bus, devfn);
    - if (dev) {
    + if ((dev = pci_scan_single_device(bus, devfn)))
    + if (!dev->is_added) /* new device? */
    nr++;

    - /*
    - * If this is a single function device,
    - * don't scan past the first function.
    - */
    - if (!dev->multifunction) {
    - if (func > 0) {
    - dev->multifunction = 1;
    - } else {
    - break;
    - }
    + if ((dev && dev->multifunction) ||
    + (!dev && pcibios_scan_all_fns(bus, devfn))) {
    + for (fn = 1; fn < 8; fn++) {
    + if ((dev = pci_scan_single_device(bus, devfn + fn))) {
    + if (!dev->is_added)
    + nr++;
    + dev->multifunction = 1;
    }
    - } else {
    - if (func == 0 && !scan_all_fns)
    - break;
    }
    }

    @@ -1192,11 +1190,24 @@ struct pci_bus * __devinit pci_scan_bus_parented(struct device *parent,
    }
    EXPORT_SYMBOL(pci_scan_bus_parented);

    +/* Does a recursive rescan of all PCI busses. */
    +void __devinit pci_rescan_busses(void)
    +{
    + struct pci_bus *bus = NULL;
    +
    + while ((bus = pci_find_next_bus(bus)) != NULL) {
    + pci_scan_child_bus(bus);
    + pci_bus_assign_resources(bus);
    + pci_bus_add_devices(bus);
    + }
    +}
    +
    #ifdef CONFIG_HOTPLUG
    EXPORT_SYMBOL(pci_add_new_bus);
    EXPORT_SYMBOL(pci_scan_slot);
    EXPORT_SYMBOL(pci_scan_bridge);
    EXPORT_SYMBOL_GPL(pci_scan_child_bus);
    +EXPORT_SYMBOL_GPL(pci_rescan_busses);
    #endif

    static int __init pci_sort_bf_cmp(const struct device *d_a, const struct device *d_b)
    --
    1.5.4.3


    \
     
     \ /
      Last update: 2009-01-29 11:59    [W:0.037 / U:29.988 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site