PCI: skip ISA ioresource alignment on some systems

Skip ISA ioresource alignment on some systems

To conserve limited PCI i/o resource on some IBM multi-node systems, the
BIOS allocates (via _CRS) and expects the kernel to use addresses in
ranges currently excluded by pcibios_align_resource() [i386/pci/i386.c].
This change allows the kernel to use the currently excluded address
ranges on the IBM x3800, x3850, and x3950.

Signed-off-by: Gary Hade <gary.hade@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 13 insertions, 0 deletions

diff --git a/arch/x86/pci/i386.c b/arch/x86/pci/i386.c
index bcd2f94b732c..055187bc255a 100644
--- a/arch/x86/pci/i386.c
+++ b/arch/x86/pci/i386.c
@@ -33,6 +33,15 @@
 
 #include "pci.h"
 
+static int
+skip_isa_ioresource_align(struct pci_dev *dev) {
+
+        if ((pci_probe & PCI_CAN_SKIP_ISA_ALIGN) &&
+            (dev->bus->bridge_ctl & PCI_BRIDGE_CTL_NO_ISA))
+                return 1;
+        return 0;
+}
+
 /*
  * We need to avoid collisions with `mirrored' VGA ports
  * and other strange ISA hardware, so we always want the
@@ -50,9 +59,13 @@ void
 pcibios_align_resource(void *data, struct resource *res,
                         resource_size_t size, resource_size_t align)
 {
+        struct pci_dev *dev = data;
+
         if (res->flags & IORESOURCE_IO) {
                 resource_size_t start = res->start;
 
+                if (skip_isa_ioresource_align(dev))
+                        return;
                 if (start & 0x300) {
                         start = (start + 0x3ff) & ~0x3ff;
                         res->start = start;