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, 3 insertions, 13 deletions

diff --git a/drivers/char/agp/ati-agp.c b/drivers/char/agp/ati-agp.c
index 2d46b713c8f..9ac3bef3bb7 100644
--- a/drivers/char/agp/ati-agp.c
+++ b/drivers/char/agp/ati-agp.c
@@ -60,18 +60,9 @@ static int ati_create_page_map(struct ati_page_map *page_map)
 	if (page_map->real == NULL)
 		return -ENOMEM;
 
-	SetPageReserved(virt_to_page(page_map->real));
+	set_memory_uc(page_map->real, 1);
 	err = map_page_into_agp(virt_to_page(page_map->real));
-	page_map->remapped = ioremap_nocache(virt_to_gart(page_map->real),
-					    PAGE_SIZE);
-	if (page_map->remapped == NULL || err) {
-		ClearPageReserved(virt_to_page(page_map->real));
-		free_page((unsigned long) page_map->real);
-		page_map->real = NULL;
-		return -ENOMEM;
-	}
-	/*CACHE_FLUSH();*/
-	global_cache_flush();
+	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);
@@ -85,8 +76,7 @@ static int ati_create_page_map(struct ati_page_map *page_map)
 static void ati_free_page_map(struct ati_page_map *page_map)
 {
 	unmap_page_from_agp(virt_to_page(page_map->real));
-	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);
 }