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>

5 files changed, 28 insertions, 26 deletions

diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 9f42d7e9c158..69f4981db80f 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -126,6 +126,8 @@ static void __iomem *__ioremap(unsigned long phys_addr, unsigned long size,
                         return NULL;
         }
 
+        WARN_ON_ONCE(page_is_ram(pfn));
+
         switch (mode) {
         case IOR_MODE_UNCACHED:
         default:
diff --git a/drivers/char/agp/amd-k7-agp.c b/drivers/char/agp/amd-k7-agp.c
index 87be46406daf..fca4d7f30443 100644
--- a/drivers/char/agp/amd-k7-agp.c
+++ b/drivers/char/agp/amd-k7-agp.c
@@ -41,6 +41,7 @@ static int amd_create_page_map(struct amd_page_map *page_map)
         if (page_map->real == NULL)
                 return -ENOMEM;
 
+#ifndef CONFIG_X86
         SetPageReserved(virt_to_page(page_map->real));
         global_cache_flush();
         page_map->remapped = ioremap_nocache(virt_to_gart(page_map->real),
@@ -52,6 +53,10 @@ static int amd_create_page_map(struct amd_page_map *page_map)
                 return -ENOMEM;
         }
         global_cache_flush();
+#else
+        set_memory_uc(page_map->real, 1);
+        page_map->remapped = page_map->real;
+#endif
 
         for (i = 0; i < PAGE_SIZE / sizeof(unsigned long); i++) {
                 writel(agp_bridge->scratch_page, page_map->remapped+i);
@@ -63,8 +68,12 @@ static int amd_create_page_map(struct amd_page_map *page_map)
 
 static void amd_free_page_map(struct amd_page_map *page_map)
 {
+#ifndef CONFIG_X86
         iounmap(page_map->remapped);
         ClearPageReserved(virt_to_page(page_map->real));
+#else
+        set_memory_wb(page_map->real, 1);
+#endif
         free_page((unsigned long) page_map->real);
 }
 
diff --git a/drivers/char/agp/ati-agp.c b/drivers/char/agp/ati-agp.c
index 2d46b713c8f2..9ac3bef3bb7a 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);
 }
 
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);
 
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);
 }