powerpc/PCI: Override pcibios_window_alignment()

This patch implements pcibios_window_alignment() so powerpc platforms can
force P2P bridge windows to be at larger alignments than the PCI spec
requires.

[bhelgaas: changelog]
Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

2 files changed, 23 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/machdep.h b/arch/powerpc/include/asm/machdep.h
index 42ce570812c1..f7706d722b39 100644
--- a/arch/powerpc/include/asm/machdep.h
+++ b/arch/powerpc/include/asm/machdep.h
@@ -214,6 +214,9 @@ struct machdep_calls {
         /* Called after scan and before resource survey */
         void (*pcibios_fixup_phb)(struct pci_controller *hose);
 
+        /* Called during PCI resource reassignment */
+        resource_size_t (*pcibios_window_alignment)(struct pci_bus *, unsigned long type);
+
         /* Called to shutdown machine specific hardware not already controlled
          * by other drivers.
          */
diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index 2aa04f29e1de..43fea543d686 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -99,6 +99,26 @@ void pcibios_free_controller(struct pci_controller *phb)
                 kfree(phb);
 }
 
+/*
+ * The function is used to return the minimal alignment
+ * for memory or I/O windows of the associated P2P bridge.
+ * By default, 4KiB alignment for I/O windows and 1MiB for
+ * memory windows.
+ */
+resource_size_t pcibios_window_alignment(struct pci_bus *bus,
+                                         unsigned long type)
+{
+        if (ppc_md.pcibios_window_alignment)
+                return ppc_md.pcibios_window_alignment(bus, type);
+
+        /*
+         * PCI core will figure out the default
+         * alignment: 4KiB for I/O and 1MiB for
+         * memory window.
+         */
+        return 1;
+}
+
 static resource_size_t pcibios_io_size(const struct pci_controller *hose)
 {
 #ifdef CONFIG_PPC64