PCI: Disable cardbus bridge MEM1 prefetchable bit

Some BIOSes enable prefetch on both MEM0 and MEM1.  But the cardbus code
assumes MEM1 is non-pref...

Discussion could be found at:
	https://lkml.org/lkml/2012/1/12/1
	https://bugzilla.kernel.org/show_bug.cgi?id=41622#c23

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Tested-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 090217afb4e1..d5897c32f669 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -914,6 +914,14 @@ static void pci_bus_size_cardbus(struct pci_bus *bus,
         if (realloc_head)
                 add_to_list(realloc_head, bridge, b_res+1, pci_cardbus_io_size, 0 /* dont care */);
 
+        /* MEM1 must not be pref mmio */
+        pci_read_config_word(bridge, PCI_CB_BRIDGE_CONTROL, &ctrl);
+        if (ctrl & PCI_CB_BRIDGE_CTL_PREFETCH_MEM1) {
+                ctrl &= ~PCI_CB_BRIDGE_CTL_PREFETCH_MEM1;
+                pci_write_config_word(bridge, PCI_CB_BRIDGE_CONTROL, ctrl);
+                pci_read_config_word(bridge, PCI_CB_BRIDGE_CONTROL, &ctrl);
+        }
+
         /*
          * Check whether prefetchable memory is supported
          * by this bridge.