PCI: reserve bus range for SR-IOV device

Reserve the bus number range used by the Virtual Function when
pcibios_assign_all_busses() returns true.

Reviewed-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Yu Zhao <yu.zhao@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

3 files changed, 44 insertions, 0 deletions

diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index b121e47402fa..5ddfc09a8d3f 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -14,6 +14,18 @@
 #include "pci.h"
 
 
+static inline u8 virtfn_bus(struct pci_dev *dev, int id)
+{
+        return dev->bus->number + ((dev->devfn + dev->sriov->offset +
+                                    dev->sriov->stride * id) >> 8);
+}
+
+static inline u8 virtfn_devfn(struct pci_dev *dev, int id)
+{
+        return (dev->devfn + dev->sriov->offset +
+                dev->sriov->stride * id) & 0xff;
+}
+
 static int sriov_init(struct pci_dev *dev, int pos)
 {
         int i;
@@ -209,3 +221,27 @@ void pci_restore_iov_state(struct pci_dev *dev)
         if (dev->is_physfn)
                 sriov_restore_state(dev);
 }
+
+/**
+ * pci_iov_bus_range - find bus range used by Virtual Function
+ * @bus: the PCI bus
+ *
+ * Returns max number of buses (exclude current one) used by Virtual
+ * Functions.
+ */
+int pci_iov_bus_range(struct pci_bus *bus)
+{
+        int max = 0;
+        u8 busnr;
+        struct pci_dev *dev;
+
+        list_for_each_entry(dev, &bus->devices, bus_list) {
+                if (!dev->is_physfn)
+                        continue;
+                busnr = virtfn_bus(dev, dev->sriov->total - 1);
+                if (busnr > max)
+                        max = busnr;
+        }
+
+        return max ? max - bus->number : 0;
+}
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index fd5ea4d445e8..5c29cb2b8e63 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -223,6 +223,7 @@ extern void pci_iov_release(struct pci_dev *dev);
 extern int pci_iov_resource_bar(struct pci_dev *dev, int resno,
                                 enum pci_bar_type *type);
 extern void pci_restore_iov_state(struct pci_dev *dev);
+extern int pci_iov_bus_range(struct pci_bus *bus);
 #else
 static inline int pci_iov_init(struct pci_dev *dev)
 {
@@ -240,6 +241,10 @@ static inline int pci_iov_resource_bar(struct pci_dev *dev, int resno,
 static inline void pci_restore_iov_state(struct pci_dev *dev)
 {
 }
+static inline int pci_iov_bus_range(struct pci_bus *bus)
+{
+        return 0;
+}
 #endif /* CONFIG_PCI_IOV */
 
 #endif /* DRIVERS_PCI_H */
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 0471f6ea1466..0ecdaea3915f 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1085,6 +1085,9 @@ unsigned int __devinit pci_scan_child_bus(struct pci_bus *bus)
         for (devfn = 0; devfn < 0x100; devfn += 8)
                 pci_scan_slot(bus, devfn);
 
+        /* Reserve buses for SR-IOV capability. */
+        max += pci_iov_bus_range(bus);
+
         /*
          * After performing arch-dependent fixup of the bus, look behind
          * all PCI-to-PCI bridges on this bus.