[PATCH] 2.5.54 AGP driver fixes for x86-64

This is just to make x86-64 boot with IOMMU and compiled in AGP driver
again.  Previously both AGP and the IOMMU code would set up an aperture,
with AGP being winner, messing up pci_map_*.

This is needed for the x86-64 update for 2.5.54 I sent earlier.

Actually using /dev/agpgart still corrupts memory unfortunately, haven't
tracked that down yet.

I also commented on some (usually 64bit, but at least one 32bit) bugs in
the driver too.

These changes should be all nops on i386.

 - Export amd k8 init function for x86-64.  It needs to be called early
   by the iommu code.  Add some comments to warn about about that (the
   upcoming VIA and SIS K8 chipsets will have the same problem)
 - Declare gatt table as u32 following the AGP spec.
 - Comment some bugs.

drivers/char/agp/agp.h

@@ -128,8 +128,8 @@ struct agp_bridge_data {
 	void *dev_private_data;
 	struct pci_dev *dev;
 	struct gatt_mask *masks;
-	unsigned long *gatt_table;
-	unsigned long *gatt_table_real;
+	u32 *gatt_table;
+	u32 *gatt_table_real;
 	unsigned long scratch_page;
 	unsigned long gart_bus_addr;
 	unsigned long gatt_bus_addr;

drivers/char/agp/amd-k8-agp.c

@@ -8,6 +8,12 @@
  * removed now).
  */ 
 
+/*
+ * On x86-64 the AGP driver needs to be initialized early by the IOMMU 
+ * code.  When you use this driver as a template for a new K8 AGP bridge
+ * driver don't forget to change arch/x86_64/kernel/pci-gart.c too -AK.
+ */
+
 #include <linux/module.h>
 #include <linux/pci.h>
 #include <linux/init.h>
@@ -63,7 +69,8 @@ static int x86_64_insert_memory(agp_memory * mem, off_t pg_start, int type)
 		return -EINVAL;
 
 	/* Make sure we can fit the range in the gatt table. */
-	if ((pg_start + mem->page_count) > num_entries)
+	/* FIXME: could wrap */
+	if (((unsigned long)pg_start + mem->page_count) > num_entries)
 		return -EINVAL;
 
 	j = pg_start;
@@ -512,7 +519,7 @@ static struct __initdata pci_driver agp_amdk8_pci_driver = {
 	.probe		= agp_amdk8_probe,
 };
 
-static int __init agp_amdk8_init(void)
+int __init agp_amdk8_init(void)
 {
 	int ret_val;
 
@@ -531,8 +538,12 @@ static void __exit agp_amdk8_cleanup(void)
 	pci_unregister_driver(&agp_amdk8_pci_driver);
 }
 
+/* On x86-64 the PCI driver needs to initialize this driver early
+   for the IOMMU, so it has to be called via a backdoor. */
+#ifndef CONFIG_GART_IOMMU
 module_init(agp_amdk8_init);
 module_exit(agp_amdk8_cleanup);
+#endif
 
 MODULE_AUTHOR("Dave Jones <davej@codemonkey.org.uk>");
 MODULE_LICENSE("GPL and additional rights");

drivers/char/agp/generic.c

@@ -469,7 +469,7 @@ int agp_generic_create_gatt_table(void)
 	for (page = virt_to_page(table); page <= virt_to_page(table_end); page++)
 		SetPageReserved(page);
 
-	agp_bridge.gatt_table_real = (unsigned long *) table;
+	agp_bridge.gatt_table_real = (u32 *) table;
 	agp_gatt_table = (void *)table; 
 	CACHE_FLUSH();
 	agp_bridge.gatt_table = ioremap_nocache(virt_to_phys(table),
@@ -486,6 +486,7 @@ int agp_generic_create_gatt_table(void)
 	}
 	agp_bridge.gatt_bus_addr = virt_to_phys(agp_bridge.gatt_table_real);
 
+	/* AK: bogus, should encode addresses > 4GB */
 	for (i = 0; i < num_entries; i++)
 		agp_bridge.gatt_table[i] = (unsigned long) agp_bridge.scratch_page;
 
@@ -586,6 +587,7 @@ int agp_generic_insert_memory(agp_memory * mem, off_t pg_start, int type)
 		return -EINVAL;
 	}
 
+	/* AK: could wrap */
 	if ((pg_start + mem->page_count) > num_entries)
 		return -EINVAL;
 
@@ -618,6 +620,8 @@ int agp_generic_remove_memory(agp_memory * mem, off_t pg_start, int type)
 		/* The generic routines know nothing of memory types */
 		return -EINVAL;
 	}
+
+	/* AK: bogus, should encode addresses > 4GB */
 	for (i = pg_start; i < (mem->page_count + pg_start); i++) {
 		agp_bridge.gatt_table[i] =
 		    (unsigned long) agp_bridge.scratch_page;