From: ddugger@redhat.com <ddugger@redhat.com>
Date: Thu, 2 Apr 2009 08:46:17 -0600
Subject: [pci] reserve bus range for SR-IOV device
Message-id: 200904021446.n32EkHRa017160@sobek.n0ano.com
O-Subject: [RHEL5.4 PATCH 12/17] BZ493152: Backport: PCI: reserve bus range for SR-IOV device
Bugzilla: 493152
RH-Acked-by: Rik van Riel <riel@redhat.com>
RH-Acked-by: Chris Wright <chrisw@redhat.com>

Upstream status: commit a28724b0fb909d247229a70761c90bb37b13366a
    Author: Yu Zhao <yu.zhao@intel.com>
    Date:   Fri Mar 20 11:25:13 2009 +0800

    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>

Signed-off-by: Gerd Hoffman <kraxel@redhat.com>
Signed-off-by: Don Dugger <donald.d.dugger@intel.com>

diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index fc809a4..2ac1ac0 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;
@@ -187,3 +199,27 @@ 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 57524e1..7fa8de8 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -137,6 +137,7 @@ 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)
 {
@@ -154,4 +155,8 @@ 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 */
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 68c79bc..1329273 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -987,6 +987,9 @@ 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.