PCI: clean up resource alignment management

Done per Linus' request and suggestions. Linus has explained that
better than I'll be able to explain:

On Thu, Mar 27, 2008 at 10:12:10AM -0700, Linus Torvalds wrote:
> Actually, before we go any further, there might be a less intrusive
> alternative: add just a couple of flags to the resource flags field (we
> still have something like 8 unused bits on 32-bit), and use those to
> implement a generic "resource_alignment()" routine.
>
> Two flags would do it:
>
>  - IORESOURCE_SIZEALIGN: size indicates alignment (regular PCI device
>    resources)
>
>  - IORESOURCE_STARTALIGN: start field is alignment (PCI bus resources
>    during probing)
>
> and then the case of both flags zero (or both bits set) would actually be
> "invalid", and we would also clear the IORESOURCE_STARTALIGN flag when we
> actually allocate the resource (so that we don't use the "start" field as
> alignment incorrectly when it no longer indicates alignment).
>
> That wouldn't be totally generic, but it would have the nice property of
> automatically at least add sanity checking for that whole "res->start has
> the odd meaning of 'alignment' during probing" and remove the need for a
> new field, and it would allow us to have a generic "resource_alignment()"
> routine that just gets a resource pointer.

Besides, I removed IORESOURCE_BUS_HAS_VGA flag which was unused for ages.

Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Gary Hade <garyhade@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 4 insertions, 1 deletions

diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 605d237364d2..d5d40a9f7929 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -44,7 +44,9 @@ struct resource_list {
 #define IORESOURCE_CACHEABLE    0x00004000
 #define IORESOURCE_RANGELENGTH  0x00008000
 #define IORESOURCE_SHADOWABLE   0x00010000
-#define IORESOURCE_BUS_HAS_VGA  0x00080000
+
+#define IORESOURCE_SIZEALIGN    0x00020000      /* size indicates alignment */
+#define IORESOURCE_STARTALIGN   0x00040000      /* start field is alignment */
 
 #define IORESOURCE_DISABLED     0x10000000
 #define IORESOURCE_UNSET        0x20000000
@@ -110,6 +112,7 @@ extern int allocate_resource(struct resource *root, struct resource *new,
                              void *alignf_data);
 int adjust_resource(struct resource *res, resource_size_t start,
                     resource_size_t size);
+resource_size_t resource_alignment(struct resource *res);
 
 /* Convenience shorthand with allocation */
 #define request_region(start,n,name)    __request_region(&ioport_resource, (start), (n), (name))