iommu: Move swap_pci_ref function to drivers/iommu/pci.h.

The swap_pci_ref function is used by the IOMMU API code for
swapping pci device pointers, while determining the iommu
group for the device.
Currently this function was being implemented for different
IOMMU drivers.  This patch moves the function to a new file,
drivers/iommu/pci.h so that the implementation can be
shared across various IOMMU drivers.
Signed-off-by: Varun Sethi <Varun.Sethi@freescale.com>
Signed-off-by: Joerg Roedel <joro@8bytes.org>

drivers/iommu/amd_iommu.c

@@ -46,6 +46,7 @@
 #include "amd_iommu_proto.h"
 #include "amd_iommu_types.h"
 #include "irq_remapping.h"
+#include "pci.h"
 
 #define CMD_SET_TYPE(cmd, t) ((cmd)->data[1] |= ((t) << 28))
 
@@ -263,12 +264,6 @@ static bool check_device(struct device *dev)
 	return true;
 }
 
-static void swap_pci_ref(struct pci_dev **from, struct pci_dev *to)
-{
-	pci_dev_put(*from);
-	*from = to;
-}
-
 static struct pci_bus *find_hosted_bus(struct pci_bus *bus)
 {
 	while (!bus->self) {

drivers/iommu/intel-iommu.c

@@ -47,6 +47,7 @@
 #include <asm/iommu.h>
 
 #include "irq_remapping.h"
+#include "pci.h"
 
 #define ROOT_SIZE		VTD_PAGE_SIZE
 #define CONTEXT_SIZE		VTD_PAGE_SIZE
@@ -4137,12 +4138,6 @@ static int intel_iommu_domain_has_cap(struct iommu_domain *domain,
 	return 0;
 }
 
-static void swap_pci_ref(struct pci_dev **from, struct pci_dev *to)
-{
-	pci_dev_put(*from);
-	*from = to;
-}
-
 #define REQ_ACS_FLAGS	(PCI_ACS_SV | PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_UF)
 
 static int intel_iommu_add_device(struct device *dev)

drivers/iommu/pci.h

+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ *
+ * Copyright (C) 2013 Red Hat, Inc.
+ * Copyright (C) 2013 Freescale Semiconductor, Inc.
+ *
+ */
+#ifndef __IOMMU_PCI_H
+#define __IOMMU_PCI_H
+
+/* Helper function for swapping pci device reference */
+static inline void swap_pci_ref(struct pci_dev **from, struct pci_dev *to)
+{
+	pci_dev_put(*from);
+	*from = to;
+}
+
+#endif  /* __IOMMU_PCI_H */