[PATCH 6/7] pci: function to retrieve alignment of p2p bars

[Gavin Shan <shangw@linux.vnet.ibm.com>]

The patch introduces function pci_align_boundary() to retrieve the
minimal alignment of p2p bars according to the argument.

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
---
 drivers/pci/host-bridge.c |   24 ++++++++++++++++++++++++
 include/linux/pci.h       |    1 +
 2 files changed, 25 insertions(+)

diff --git a/drivers/pci/host-bridge.c b/drivers/pci/host-bridge.c
index 1854a2d..dc9a95e 100644
--- a/drivers/pci/host-bridge.c
+++ b/drivers/pci/host-bridge.c
@@ -105,3 +105,27 @@ void pcibios_bus_to_resource(struct pci_dev *dev, struct resource *res,
 }
 
 EXPORT_SYMBOL(pcibios_bus_to_resource);
+
+resource_size_t pci_align_boundary(struct pci_bus *bus, unsigned long flags)
+{
+	resource_size_t align = 0;
+	struct pci_host_bridge *bridge = find_pci_host_bridge(bus);
+
+	flags &= (IORESOURCE_IO | IORESOURCE_MEM | IORESOURCE_PREFETCH);
+	switch (flags) {
+	case IORESOURCE_IO:
+		align = (1 << bridge->io_align_shift);
+		break;
+	case IORESOURCE_MEM:
+		align = (1 << bridge->mem_align_shift);
+		break;
+	case (IORESOURCE_MEM | IORESOURCE_PREFETCH):
+		align = (1 << bridge->pmem_align_shift);
+		break;
+	default:
+		printk(KERN_WARNING "%s: invalid flags 0x%lx\n",
+			__func__, flags);
+	}
+
+	return align;
+}
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 2b2b38d..64523ef 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -673,6 +673,7 @@ void __pcibios_bus_to_resource(struct pci_bus *bus, struct resource *res,
 			       struct pci_bus_region *region);
 void pcibios_bus_to_resource(struct pci_dev *dev, struct resource *res,
 			     struct pci_bus_region *region);
+resource_size_t pci_align_boundary(struct pci_bus *bus, unsigned long flags);
 void pcibios_scan_specific_bus(int busn);
 extern struct pci_bus *pci_find_bus(int domain, int busnr);
 void pci_bus_add_devices(const struct pci_bus *bus);
-- 
1.7.9.5