1 files changed, 138 insertions, 0 deletions
diff --git a/linux-core/drm_uncached.c b/linux-core/drm_uncached.c
new file mode 100644
index 00000000..9c7183b0
--- /dev/null
+++ b/linux-core/drm_uncached.c
@@ -0,0 +1,138 @@
+/*
+ * Copyright (c) Red Hat Inc.
+
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sub license,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * Authors: Dave Airlie <airlied@redhat.com>
+ */
+
+/* simple list based uncached page allocator 
+ * - Add chunks of 1MB to the allocator at a time.
+ * - Use page->lru to keep a free list
+ * - doesn't track currently in use pages
+ * 
+ *  TODO: Add shrinker support
+ */
+
+#include "drmP.h"
+#include <asm/agp.h>
+
+static struct list_head uncached_free_list;
+
+static struct mutex uncached_mutex;
+static int uncached_inited;
+static int total_uncached_pages;
+
+/* add 1MB at a time */
+#define NUM_PAGES_TO_ADD 256
+
+static void drm_uncached_page_put(struct page *page)
+{
+	unmap_page_from_agp(page);
+	put_page(page);
+	__free_page(page);
+}
+
+int drm_uncached_add_pages_locked(int num_pages)
+{
+	struct page *page;
+	int i;
+
+	DRM_DEBUG("adding uncached memory %ld\n", num_pages * PAGE_SIZE);
+	for (i = 0; i < num_pages; i++) {
+
+		page = alloc_page(GFP_KERNEL | __GFP_ZERO | GFP_DMA32);
+		if (!page) {
+			DRM_ERROR("unable to get page %d\n", i);
+			return i;
+		}
+
+		get_page(page);
+#ifdef CONFIG_X86
+		set_memory_wc((unsigned long)page_address(page), 1);
+#else
+		map_page_into_agp(page);
+#endif
+
+		list_add(&page->lru, &uncached_free_list);
+		total_uncached_pages++;
+	}
+	return i;
+}
+
+struct page *drm_get_uncached_page(void)
+{
+	struct page *page = NULL;
+	int ret;
+
+	mutex_lock(&uncached_mutex);
+	if (list_empty(&uncached_free_list)) {
+		ret = drm_uncached_add_pages_locked(NUM_PAGES_TO_ADD);
+		if (ret == 0)
+			return NULL;
+	}
+
+	page = list_first_entry(&uncached_free_list, struct page, lru);
+	list_del(&page->lru);
+
+	mutex_unlock(&uncached_mutex);
+	return page;
+}
+
+void drm_put_uncached_page(struct page *page)
+{
+	mutex_lock(&uncached_mutex);
+	list_add(&page->lru, &uncached_free_list);
+	mutex_unlock(&uncached_mutex);
+}
+
+void drm_uncached_release_all_pages(void)
+{
+	struct page *page, *tmp;
+
+	list_for_each_entry_safe(page, tmp, &uncached_free_list, lru) {
+		list_del(&page->lru);
+		drm_uncached_page_put(page);
+	}
+}
+
+int drm_uncached_init(void)
+{
+
+	if (uncached_inited)
+		return 0;
+
+	INIT_LIST_HEAD(&uncached_free_list);
+
+	mutex_init(&uncached_mutex);
+	uncached_inited = 1;
+	return 0;
+
+}
+
+void drm_uncached_fini(void)
+{
+	if (!uncached_inited)
+		return;
+	
+	uncached_inited = 0;
+	drm_uncached_release_all_pages();
+}
+