PCI: Factor out pci_bus_wait_crs()

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: pass pointer, not value, to pci_bus_wait_crs() so caller gets
correct Vendor ID]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 5e001bb..f09d8cd 100644 (file)
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1858,30 +1858,24 @@ static bool pci_bus_crs_vendor_id(u32 l)
        return (l & 0xffff) == 0x0001;
 }
 
-bool pci_bus_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *l,
-                               int crs_timeout)
+static 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 (!pci_bus_crs_vendor_id(*l))
+               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 (pci_bus_crs_vendor_id(*l)) {
-               if (!crs_timeout)
-                       return false;
-
-               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));
@@ -1897,6 +1891,23 @@ 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;
+
+       if (pci_bus_crs_vendor_id(*l))
+               return pci_bus_wait_crs(bus, devfn, l, timeout);
+
+       return true;
+}
 EXPORT_SYMBOL(pci_bus_read_dev_vendor_id);
 
 /*