agp: Add generic support for graphics dma remapping

New driver hooks for support graphics memory dma remapping
are introduced in this patch. It makes generic code can
tell if current device needs dma remapping, then call driver
provided interfaces for mapping and unmapping. Change has
also been made to handle scratch_page in remapping case.

Signed-off-by: Zhenyu Wang <zhenyu.z.wang@intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/drivers/char/agp/backend.c b/drivers/char/agp/backend.c
index 3bd7e503de41..19ac3663acdc 100644
--- a/drivers/char/agp/backend.c
+++ b/drivers/char/agp/backend.c
@@ -152,6 +152,15 @@ static int agp_backend_initialize(struct agp_bridge_data *bridge)
                 bridge->scratch_page_real = phys_to_gart(page_to_phys(page));
                 bridge->scratch_page = bridge->driver->mask_memory(bridge,
                                            phys_to_gart(page_to_phys(page)), 0);
+
+                if (bridge->driver->agp_map_page &&
+                    bridge->driver->agp_map_page(phys_to_virt(page_to_phys(page)),
+                                                &bridge->scratch_page_dma)) {
+                        dev_err(&bridge->dev->dev,
+                                "unable to dma-map scratch page\n");
+                        rc = -ENOMEM;
+                        goto err_out_nounmap;
+                }
         }
 
         size_value = bridge->driver->fetch_size();
@@ -191,6 +200,13 @@ static int agp_backend_initialize(struct agp_bridge_data *bridge)
         return 0;
 
 err_out:
+        if (bridge->driver->needs_scratch_page &&
+            bridge->driver->agp_unmap_page) {
+                void *va = gart_to_virt(bridge->scratch_page_real);
+
+                bridge->driver->agp_unmap_page(va, bridge->scratch_page_dma);
+        }
+err_out_nounmap:
         if (bridge->driver->needs_scratch_page) {
                 void *va = gart_to_virt(bridge->scratch_page_real);
 
@@ -221,6 +237,10 @@ static void agp_backend_cleanup(struct agp_bridge_data *bridge)
             bridge->driver->needs_scratch_page) {
                 void *va = gart_to_virt(bridge->scratch_page_real);
 
+                if (bridge->driver->agp_unmap_page)
+                        bridge->driver->agp_unmap_page(va,
+                                               bridge->scratch_page_dma);
+
                 bridge->driver->agp_destroy_page(va, AGP_PAGE_DESTROY_UNMAP);
                 bridge->driver->agp_destroy_page(va, AGP_PAGE_DESTROY_FREE);
         }