PCI legacy resource fix

Since commit 368c73d4f689dae0807d0a2aa74c61fd2b9b075f the kernel will try
to update the non-writeable BAR registers 0..3 of PIIX4 IDE adapters if
pci_assign_unassigned_resources() is used to do full resource assignment of
the bus.  This fails because in the PIIX4 these BAR registers have
implicitly assumed values and read back as zero; it used to work because
the kernel used to just write zero to that register the read back value did
match what was written.

The fix is a new resource flag IORESOURCE_PCI_FIXED used to mark a resource
as non-movable.  This will also be useful to keep other import system
resources from being moved around - for example system consoles on PCI
busses.

[akpm@osdl.org: cleanup]
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 3 insertions, 0 deletions

diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index cf8696d4a138..15228d79c5bc 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -91,6 +91,9 @@ struct resource_list {
 #define IORESOURCE_ROM_COPY		(1<<2)	/* ROM is alloc'd copy, resource field overlaid */
 #define IORESOURCE_ROM_BIOS_COPY	(1<<3)	/* ROM is BIOS copy, resource field overlaid */
 
+/* PCI control bits.  Shares IORESOURCE_BITS with above PCI ROM.  */
+#define IORESOURCE_PCI_FIXED		(1<<4)	/* Do not move resource */
+
 /* PC/ISA/whatever - the normal PC address spaces: IO and memory */
 extern struct resource ioport_resource;
 extern struct resource iomem_resource;