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, 9 insertions, 0 deletions

diff --git a/drivers/char/agp/generic.c b/drivers/char/agp/generic.c
index 7484bc759c4c..7fc0c99a3a58 100644
--- a/drivers/char/agp/generic.c
+++ b/drivers/char/agp/generic.c
@@ -932,9 +932,14 @@ int agp_generic_create_gatt_table(struct agp_bridge_data *bridge)
         agp_gatt_table = (void *)table;
 
         bridge->driver->cache_flush();
+#ifdef CONFIG_X86
+        set_memory_uc((unsigned long)table, 1 << page_order);
+        bridge->gatt_table = (void *)table;
+#else
         bridge->gatt_table = ioremap_nocache(virt_to_gart(table),
                                         (PAGE_SIZE * (1 << page_order)));
         bridge->driver->cache_flush();
+#endif
 
         if (bridge->gatt_table == NULL) {
                 for (page = virt_to_page(table); page <= virt_to_page(table_end); page++)
@@ -991,7 +996,11 @@ int agp_generic_free_gatt_table(struct agp_bridge_data *bridge)
          * called, then all agp memory is deallocated and removed
          * from the table. */
 
+#ifdef CONFIG_X86
+        set_memory_wb((unsigned long)bridge->gatt_table, 1 << page_order);
+#else
         iounmap(bridge->gatt_table);
+#endif
         table = (char *) bridge->gatt_table_real;
         table_end = table + ((PAGE_SIZE * (1 << page_order)) - 1);