fix historic ioremap() abuse in AGP

Several AGP drivers right now use ioremap_nocache() on kernel ram in order
to turn a page of regular memory uncached.

There are two problems with this:

    1) This is a total nightmare for the ioremap() implementation to keep
       various mappings of the same page coherent.

    2) It's a total nightmare for the AGP code since it adds a ton of
       complexity in terms of keeping track of 2 different pointers to
       the same thing, in terms of error handling etc etc.

This patch fixes this by making the AGP drivers use the new
set_memory_XX APIs instead.

Note: amd-k7-agp.c is built on Alpha too, and generic.c is built
on ia64 as well, which do not yet have the set_memory_*() APIs,
so for them some we have a few ugly #ifdefs - hopefully they'll
be fixed soon.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Dave Airlie <airlied@linux.ie>

1 files changed, 5 insertions, 13 deletions

diff --git a/drivers/char/agp/sworks-agp.c b/drivers/char/agp/sworks-agp.c
index 551ef25063ef..ae06f8982068 100644
--- a/drivers/char/agp/sworks-agp.c
+++ b/drivers/char/agp/sworks-agp.c
@@ -52,28 +52,20 @@ static int serverworks_create_page_map(struct serverworks_page_map *page_map)
         if (page_map->real == NULL) {
                 return -ENOMEM;
         }
-        SetPageReserved(virt_to_page(page_map->real));
-        global_cache_flush();
-        page_map->remapped = ioremap_nocache(virt_to_gart(page_map->real),
-                                            PAGE_SIZE);
-        if (page_map->remapped == NULL) {
-                ClearPageReserved(virt_to_page(page_map->real));
-                free_page((unsigned long) page_map->real);
-                page_map->real = NULL;
-                return -ENOMEM;
-        }
-        global_cache_flush();
+
+        set_memory_uc(page_map->real, 1);
+        page_map->remapped = page_map->real;
 
         for (i = 0; i < PAGE_SIZE / sizeof(unsigned long); i++)
                 writel(agp_bridge->scratch_page, page_map->remapped+i);
+                /* Red Pen: Everyone else does pci posting flush here */
 
         return 0;
 }
 
 static void serverworks_free_page_map(struct serverworks_page_map *page_map)
 {
-        iounmap(page_map->remapped);
-        ClearPageReserved(virt_to_page(page_map->real));
+        set_memory_wb(page_map->real, 1);
         free_page((unsigned long) page_map->real);
 }