[PATCH] AGP fix for Xen VMM

When Linux is running on the Xen virtual machine monitor, physical
addresses are virtualised and cannot be directly referenced by the AGP
GART.  This patch fixes the GART driver for Xen by adding a layer of
abstraction between physical addresses and 'GART addresses'.

Architecture-specific functions are also defined for allocating and freeing
the GATT.  Xen requires this to ensure that table really is contiguous from
the point of view of the GART.

These extra interface functions are defined as 'no-ops' for all existing
architectures that use the GART driver.

Signed-off-by: Keir Fraser <keir@xensource.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Dave Jones <davej@redhat.com>

1 files changed, 8 insertions, 9 deletions

diff --git a/drivers/char/agp/generic.c b/drivers/char/agp/generic.c
index c321a924e38..d62505b5d25 100644
--- a/drivers/char/agp/generic.c
+++ b/drivers/char/agp/generic.c
@@ -153,7 +153,7 @@ void agp_free_memory(struct agp_memory *curr)
 	}
 	if (curr->page_count != 0) {
 		for (i = 0; i < curr->page_count; i++) {
-			curr->bridge->driver->agp_destroy_page(phys_to_virt(curr->memory[i]));
+			curr->bridge->driver->agp_destroy_page(gart_to_virt(curr->memory[i]));
 		}
 	}
 	agp_free_key(curr->key);
@@ -209,7 +209,7 @@ struct agp_memory *agp_allocate_memory(struct agp_bridge_data *bridge,
 			agp_free_memory(new);
 			return NULL;
 		}
-		new->memory[i] = virt_to_phys(addr);
+		new->memory[i] = virt_to_gart(addr);
 		new->page_count++;
 	}
        new->bridge = bridge;
@@ -806,8 +806,7 @@ int agp_generic_create_gatt_table(struct agp_bridge_data *bridge)
 				break;
 			}
 
-			table = (char *) __get_free_pages(GFP_KERNEL,
-							  page_order);
+			table = alloc_gatt_pages(page_order);
 
 			if (table == NULL) {
 				i++;
@@ -838,7 +837,7 @@ int agp_generic_create_gatt_table(struct agp_bridge_data *bridge)
 		size = ((struct aper_size_info_fixed *) temp)->size;
 		page_order = ((struct aper_size_info_fixed *) temp)->page_order;
 		num_entries = ((struct aper_size_info_fixed *) temp)->num_entries;
-		table = (char *) __get_free_pages(GFP_KERNEL, page_order);
+		table = alloc_gatt_pages(page_order);
 	}
 
 	if (table == NULL)
@@ -853,7 +852,7 @@ int agp_generic_create_gatt_table(struct agp_bridge_data *bridge)
 	agp_gatt_table = (void *)table;
 
 	bridge->driver->cache_flush();
-	bridge->gatt_table = ioremap_nocache(virt_to_phys(table),
+	bridge->gatt_table = ioremap_nocache(virt_to_gart(table),
 					(PAGE_SIZE * (1 << page_order)));
 	bridge->driver->cache_flush();
 
@@ -861,11 +860,11 @@ int agp_generic_create_gatt_table(struct agp_bridge_data *bridge)
 		for (page = virt_to_page(table); page <= virt_to_page(table_end); page++)
 			ClearPageReserved(page);
 
-		free_pages((unsigned long) table, page_order);
+		free_gatt_pages(table, page_order);
 
 		return -ENOMEM;
 	}
-	bridge->gatt_bus_addr = virt_to_phys(bridge->gatt_table_real);
+	bridge->gatt_bus_addr = virt_to_gart(bridge->gatt_table_real);
 
 	/* AK: bogus, should encode addresses > 4GB */
 	for (i = 0; i < num_entries; i++) {
@@ -919,7 +918,7 @@ int agp_generic_free_gatt_table(struct agp_bridge_data *bridge)
 	for (page = virt_to_page(table); page <= virt_to_page(table_end); page++)
 		ClearPageReserved(page);
 
-	free_pages((unsigned long) bridge->gatt_table_real, page_order);
+	free_gatt_pages(bridge->gatt_table_real, page_order);
 
 	agp_gatt_table = NULL;
 	bridge->gatt_table = NULL;