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    Subject[PATCH v11 2/4] PCI: Factor out pci_bus_wait_crs()
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    From: Sinan Kaya <okaya@codeaurora.org>

    Configuration Request Retry Status (CRS) was previously hidden inside
    pci_bus_read_dev_vendor_id(). We want to add support for CRS in other
    situations, such as waiting for a device to become ready after a Function
    Level Reset.

    Move CRS handling into pci_bus_wait_crs() so it can be called from other
    places.

    Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
    [bhelgaas: move CRS reserved Vendor ID test into pci_bus_wait_crs(), remove
    EXPORT_SYMBOL]
    Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
    ---
    drivers/pci/pci.h | 1 +
    drivers/pci/probe.c | 39 +++++++++++++++++++++++----------------
    2 files changed, 24 insertions(+), 16 deletions(-)

    diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
    index 22e061738c6f..b0857052c04a 100644
    --- a/drivers/pci/pci.h
    +++ b/drivers/pci/pci.h
    @@ -235,6 +235,7 @@ enum pci_bar_type {
    pci_bar_mem64, /* A 64-bit memory BAR */
    };

    +bool pci_bus_wait_crs(struct pci_bus *bus, int devfn, u32 *l, int timeout);
    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);
    diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
    index 08ea844ac4ba..342a86640c6b 100644
    --- a/drivers/pci/probe.c
    +++ b/drivers/pci/probe.c
    @@ -1824,33 +1824,26 @@ struct pci_dev *pci_alloc_dev(struct pci_bus *bus)
    }
    EXPORT_SYMBOL(pci_alloc_dev);

    -bool pci_bus_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *l,
    - int crs_timeout)
    +bool pci_bus_wait_crs(struct pci_bus *bus, int devfn, u32 *l, int timeout)
    {
    int delay = 1;

    - if (pci_bus_read_config_dword(bus, devfn, PCI_VENDOR_ID, l))
    - return false;
    + if ((*l & 0xffff) != 0x0001)
    + return true; /* not a CRS completion */

    - /* some broken boards return 0 or ~0 if a slot is empty: */
    - if (*l == 0xffffffff || *l == 0x00000000 ||
    - *l == 0x0000ffff || *l == 0xffff0000)
    - return false;
    + if (!timeout)
    + return false; /* CRS, but caller doesn't want to wait */

    /*
    - * Configuration Request Retry Status. Some root ports return the
    - * actual device ID instead of the synthetic ID (0xFFFF) required
    - * by the PCIe spec. Ignore the device ID and only check for
    - * (vendor id == 1).
    + * We got the reserved Vendor ID that indicates a completion with
    + * Configuration Request Retry Status (CRS). Retry until we get a
    + * valid Vendor ID or we time out.
    */
    while ((*l & 0xffff) == 0x0001) {
    - if (!crs_timeout)
    - return false;
    -
    msleep(delay);
    delay *= 2;

    - if (delay > crs_timeout) {
    + if (delay > timeout) {
    printk(KERN_WARNING "pci %04x:%02x:%02x.%d: not responding\n",
    pci_domain_nr(bus), bus->number, PCI_SLOT(devfn),
    PCI_FUNC(devfn));
    @@ -1863,6 +1856,20 @@ bool pci_bus_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *l,

    return true;
    }
    +
    +bool pci_bus_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *l,
    + int timeout)
    +{
    + if (pci_bus_read_config_dword(bus, devfn, PCI_VENDOR_ID, l))
    + return false;
    +
    + /* some broken boards return 0 or ~0 if a slot is empty: */
    + if (*l == 0xffffffff || *l == 0x00000000 ||
    + *l == 0x0000ffff || *l == 0xffff0000)
    + return false;
    +
    + return pci_bus_wait_crs(bus, devfn, l, timeout);
    +}
    EXPORT_SYMBOL(pci_bus_read_dev_vendor_id);

    /*
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