ARM: Make PCI I/O space optional

For callers of pci_common_init_dev(), we previously always required a PCI
I/O port resource.  If the caller's ->setup() function had added an I/O
resource, we used that; otherwise, we added a default 64K I/O port space
for it.

There are PCI host bridges that do not support I/O port space, and we
should not add fictitious spaces for them.

If a caller sets struct hw_pci.io_optional, assume it is responsible for
adding any I/O port resource it desires, and do not add any default I/O
port space.

Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

1 files changed, 11 insertions, 2 deletions

diff --git a/arch/arm/kernel/bios32.c b/arch/arm/kernel/bios32.c
index 05e61a2eeabe..65f12ef6aa62 100644
--- a/arch/arm/kernel/bios32.c
+++ b/arch/arm/kernel/bios32.c
@@ -410,7 +410,8 @@ static int pcibios_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
         return irq;
 }
 
-static int pcibios_init_resources(int busnr, struct pci_sys_data *sys)
+static int pcibios_init_resource(int busnr, struct pci_sys_data *sys,
+                                 int io_optional)
 {
         int ret;
         struct resource_entry *window;
@@ -420,6 +421,14 @@ static int pcibios_init_resources(int busnr, struct pci_sys_data *sys)
                          &iomem_resource, sys->mem_offset);
         }
 
+        /*
+         * If a platform says I/O port support is optional, we don't add
+         * the default I/O space.  The platform is responsible for adding
+         * any I/O space it needs.
+         */
+        if (io_optional)
+                return 0;
+
         resource_list_for_each_entry(window, &sys->resources)
                 if (resource_type(window->res) == IORESOURCE_IO)
                         return 0;
@@ -466,7 +475,7 @@ static void pcibios_init_hw(struct device *parent, struct hw_pci *hw,
                 if (ret > 0) {
                         struct pci_host_bridge *host_bridge;
 
-                        ret = pcibios_init_resources(nr, sys);
+                        ret = pcibios_init_resource(nr, sys, hw->io_optional);
                         if (ret)  {
                                 kfree(sys);
                                 break;