[AGP] add agp_num_entries() function to determine GATT table size - reserved IOMMU entries.

Currently, only the K8 GART needs this, but this is cleaner than
exporting the agp_reserved_memory variable.

drivers/char/agp/agp.h

 /*
- * AGPGART module version 0.99
+ * AGPGART module version 0.100
+ * Copyright (C) 2002 Dave Jones
  * Copyright (C) 1999 Jeff Hartmann
  * Copyright (C) 1999 Precision Insight, Inc.
  * Copyright (C) 1999 Xi Graphics, Inc.
@@ -46,6 +47,7 @@ void agp_generic_destroy_page(void *addr);
 int agp_generic_suspend(void);
 void agp_generic_resume(void);
 void agp_free_key(int key);
+int agp_num_entries(void);
 
 #define PFX "agpgart: "
 

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

@@ -14,8 +14,6 @@
 #include <linux/agp_backend.h>
 #include "agp.h"
 
-extern int agp_memory_reserved;
-
 static u_int64_t pci_read64 (struct pci_dev *dev, int reg)
 {
 	union {
@@ -48,16 +46,13 @@ static void pci_write64 (struct pci_dev *dev, int reg, u64 value)
 static int x86_64_insert_memory(agp_memory * mem, off_t pg_start, int type)
 {
 	int i, j, num_entries;
-	void *temp;
 	long tmp;
 	u32 pte;
 	u64 addr;
 
 	temp = agp_bridge.current_size;
 
-	num_entries = A_SIZE_32(temp)->num_entries;
-
-	num_entries -= agp_memory_reserved>>PAGE_SHIFT;
+	num_entries = agp_num_entries();
 
 	if (type != 0 || mem->type != 0)
 		return -EINVAL;

drivers/char/agp/generic.c

@@ -203,6 +203,40 @@ static int agp_return_size(void)
 	return current_size;
 }
 
+int agp_num_entries(void)
+{
+	int num_entries;
+	void *temp;
+
+	temp = agp_bridge.current_size;
+
+	switch (agp_bridge.size_type) {
+	case U8_APER_SIZE:
+		num_entries = A_SIZE_8(temp)->num_entries;
+		break;
+	case U16_APER_SIZE:
+		num_entries = A_SIZE_16(temp)->num_entries;
+		break;
+	case U32_APER_SIZE:
+		num_entries = A_SIZE_32(temp)->num_entries;
+		break;
+	case LVL2_APER_SIZE:
+		num_entries = A_SIZE_LVL2(temp)->num_entries;
+		break;
+	case FIXED_APER_SIZE:
+		num_entries = A_SIZE_FIX(temp)->num_entries;
+		break;
+	default:
+		num_entries = 0;
+		break;
+	}
+
+	num_entries -= agp_memory_reserved>>PAGE_SHIFT;
+	if (num_entries<0)
+		num_entries = 0;
+	return num_entries;
+}
+
 /* Routine to copy over information structure */
 
 int agp_copy_info(agp_kern_info * info)
@@ -713,3 +747,5 @@ EXPORT_SYMBOL(agp_generic_alloc_by_type);
 EXPORT_SYMBOL(agp_generic_free_by_type);
 EXPORT_SYMBOL(global_cache_flush);
 
+EXPORT_SYMBOL_GPL(agp_num_entries);
+