PCI: Add pcibios_iov_resource_alignment() interface

Per the SR-IOV spec r1.1, sec 3.3.14, the required alignment of a PF's IOV
BAR is the size of an individual VF BAR, and the size consumed is the
individual VF BAR size times NumVFs.

The PowerNV platform has additional alignment requirements to help support
its Partitionable Endpoint device isolation feature (see
Documentation/powerpc/pci_iov_resource_on_powernv.txt).

Add a pcibios_iov_resource_alignment() interface to allow platforms to
request additional alignment.

[bhelgaas: changelog, adapt to reworked pci_sriov_resource_alignment(),
drop "align" parameter]
Signed-off-by: Wei Yang <weiyang@linux.vnet.ibm.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

drivers/pci/iov.c

@@ -569,6 +569,12 @@ int pci_iov_resource_bar(struct pci_dev *dev, int resno)
 		4 * (resno - PCI_IOV_RESOURCES);
 }
 
+resource_size_t __weak pcibios_iov_resource_alignment(struct pci_dev *dev,
+						      int resno)
+{
+	return pci_iov_resource_size(dev, resno);
+}
+
 /**
  * pci_sriov_resource_alignment - get resource alignment for VF BAR
  * @dev: the PCI device
@@ -581,7 +587,7 @@ int pci_iov_resource_bar(struct pci_dev *dev, int resno)
  */
 resource_size_t pci_sriov_resource_alignment(struct pci_dev *dev, int resno)
 {
-	return pci_iov_resource_size(dev, resno);
+	return pcibios_iov_resource_alignment(dev, resno);
 }
 
 /**

include/linux/pci.h

@@ -1174,6 +1174,7 @@ unsigned char pci_bus_max_busnr(struct pci_bus *bus);
 void pci_setup_bridge(struct pci_bus *bus);
 resource_size_t pcibios_window_alignment(struct pci_bus *bus,
 					 unsigned long type);
+resource_size_t pcibios_iov_resource_alignment(struct pci_dev *dev, int resno);
 
 #define PCI_VGA_STATE_CHANGE_BRIDGE (1 << 0)
 #define PCI_VGA_STATE_CHANGE_DECODES (1 << 1)