+/*
+ * Find the drm_map that covers the range [offset, offset+size).
+ */
+static inline drm_map_t *drm_lookup_map(unsigned long offset,
+ unsigned long size, drm_device_t * dev)
+{
+ struct list_head *list;
+ drm_map_list_t *r_list;
+ drm_map_t *map;
+
+ list_for_each(list, &dev->maplist->head) {
+ r_list = (drm_map_list_t *) list;
+ map = r_list->map;
+ if (!map)
+ continue;
+ if (map->offset <= offset
+ && (offset + size) <= (map->offset + map->size))
+ return map;
+ }
+ return NULL;
+}
+
+static inline void *agp_remap(unsigned long offset, unsigned long size,
+ drm_device_t * dev)
+{
+ unsigned long *phys_addr_map, i, num_pages =
+ PAGE_ALIGN(size) / PAGE_SIZE;
+ struct drm_agp_mem *agpmem;
+ struct page **page_map;
+ void *addr;
+
+ size = PAGE_ALIGN(size);
+
+#ifdef __alpha__
+ offset -= dev->hose->mem_space->start;
+#endif
+
+ for (agpmem = dev->agp->memory; agpmem; agpmem = agpmem->next)
+ if (agpmem->bound <= offset
+ && (agpmem->bound + (agpmem->pages << PAGE_SHIFT)) >=
+ (offset + size))
+ break;
+ if (!agpmem)
+ return NULL;
+
+ /*
+ * OK, we're mapping AGP space on a chipset/platform on which memory accesses by
+ * the CPU do not get remapped by the GART. We fix this by using the kernel's
+ * page-table instead (that's probably faster anyhow...).
+ */
+ /* note: use vmalloc() because num_pages could be large... */
+ page_map = vmalloc(num_pages * sizeof(struct page *));
+ if (!page_map)
+ return NULL;
+
+ phys_addr_map =
+ agpmem->memory->memory + (offset - agpmem->bound) / PAGE_SIZE;
+ for (i = 0; i < num_pages; ++i)
+ page_map[i] = pfn_to_page(phys_addr_map[i] >> PAGE_SHIFT);
+ addr = vmap(page_map, num_pages, VM_IOREMAP, PAGE_AGP);
+ vfree(page_map);
+
+ return addr;
+}
+