PCI: Separate pci_bus_read_dev_vendor_id from pci_scan_device

We can reuse it for pciehp probing.

-v2: according to Kenji, fix crs timeout checking, and export the function
     for later use when pciehp is compiled as a module.

Suggested-by: Matthew Wilcox <matthew@wil.cx>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

2 files changed, 33 insertions, 17 deletions

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 1009a5e88e5..aaf7ff8c517 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -207,6 +207,8 @@ enum pci_bar_type {
         pci_bar_mem64,          /* A 64-bit memory BAR */
 };
 
+bool pci_bus_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *pl,
+                                int crs_timeout);
 extern int pci_setup_device(struct pci_dev *dev);
 extern int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
                                 struct resource *res, unsigned int reg);
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index aad7d0ff6b0..9f2ff8c5dc2 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1118,40 +1118,54 @@ struct pci_dev *alloc_pci_dev(void)
 }
 EXPORT_SYMBOL(alloc_pci_dev);
 
-/*
- * Read the config data for a PCI device, sanity-check it
- * and fill in the dev structure...
- */
-static struct pci_dev *pci_scan_device(struct pci_bus *bus, int devfn)
+bool pci_bus_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *l,
+                                 int crs_timeout)
 {
-        struct pci_dev *dev;
-        u32 l;
         int delay = 1;
 
-        if (pci_bus_read_config_dword(bus, devfn, PCI_VENDOR_ID, &l))
-                return NULL;
+        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 NULL;
+        if (*l == 0xffffffff || *l == 0x00000000 ||
+            *l == 0x0000ffff || *l == 0xffff0000)
+                return false;
 
         /* Configuration request Retry Status */
-        while (l == 0xffff0001) {
+        while (*l == 0xffff0001) {
+                if (!crs_timeout)
+                        return false;
+
                 msleep(delay);
                 delay *= 2;
-                if (pci_bus_read_config_dword(bus, devfn, PCI_VENDOR_ID, &l))
-                        return NULL;
+                if (pci_bus_read_config_dword(bus, devfn, PCI_VENDOR_ID, l))
+                        return false;
                 /* Card hasn't responded in 60 seconds?  Must be stuck. */
-                if (delay > 60 * 1000) {
+                if (delay > crs_timeout) {
                         printk(KERN_WARNING "pci %04x:%02x:%02x.%d: not "
                                         "responding\n", pci_domain_nr(bus),
                                         bus->number, PCI_SLOT(devfn),
                                         PCI_FUNC(devfn));
-                        return NULL;
+                        return false;
                 }
         }
 
+        return true;
+}
+EXPORT_SYMBOL(pci_bus_read_dev_vendor_id);
+
+/*
+ * Read the config data for a PCI device, sanity-check it
+ * and fill in the dev structure...
+ */
+static struct pci_dev *pci_scan_device(struct pci_bus *bus, int devfn)
+{
+        struct pci_dev *dev;
+        u32 l;
+
+        if (!pci_bus_read_dev_vendor_id(bus, devfn, &l, 60*1000))
+                return NULL;
+
         dev = alloc_pci_dev();
         if (!dev)
                 return NULL;