drm: move ttm global code to core drm

I wrote this for the prime sharing work, but I also noticed other external
non-upstream drivers from a large company carrying a similiar patch, so I
may as well ship it in master.

Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 112 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_global.c b/drivers/gpu/drm/drm_global.c
new file mode 100644
index 00000000000..c87dc96444d
--- /dev/null
+++ b/drivers/gpu/drm/drm_global.c
@@ -0,0 +1,112 @@
+/**************************************************************************
+ *
+ * Copyright 2008-2009 VMware, Inc., Palo Alto, CA., USA
+ * All Rights Reserved.
+ *
+ * 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 COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS 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: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
+ */
+
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include "drm_global.h"
+
+struct drm_global_item {
+	struct mutex mutex;
+	void *object;
+	int refcount;
+};
+
+static struct drm_global_item glob[DRM_GLOBAL_NUM];
+
+void drm_global_init(void)
+{
+	int i;
+
+	for (i = 0; i < DRM_GLOBAL_NUM; ++i) {
+		struct drm_global_item *item = &glob[i];
+		mutex_init(&item->mutex);
+		item->object = NULL;
+		item->refcount = 0;
+	}
+}
+
+void drm_global_release(void)
+{
+	int i;
+	for (i = 0; i < DRM_GLOBAL_NUM; ++i) {
+		struct drm_global_item *item = &glob[i];
+		BUG_ON(item->object != NULL);
+		BUG_ON(item->refcount != 0);
+	}
+}
+
+int drm_global_item_ref(struct drm_global_reference *ref)
+{
+	int ret;
+	struct drm_global_item *item = &glob[ref->global_type];
+	void *object;
+
+	mutex_lock(&item->mutex);
+	if (item->refcount == 0) {
+		item->object = kzalloc(ref->size, GFP_KERNEL);
+		if (unlikely(item->object == NULL)) {
+			ret = -ENOMEM;
+			goto out_err;
+		}
+
+		ref->object = item->object;
+		ret = ref->init(ref);
+		if (unlikely(ret != 0))
+			goto out_err;
+
+	}
+	++item->refcount;
+	ref->object = item->object;
+	object = item->object;
+	mutex_unlock(&item->mutex);
+	return 0;
+out_err:
+	mutex_unlock(&item->mutex);
+	item->object = NULL;
+	return ret;
+}
+EXPORT_SYMBOL(drm_global_item_ref);
+
+void drm_global_item_unref(struct drm_global_reference *ref)
+{
+	struct drm_global_item *item = &glob[ref->global_type];
+
+	mutex_lock(&item->mutex);
+	BUG_ON(item->refcount == 0);
+	BUG_ON(ref->object != item->object);
+	if (--item->refcount == 0) {
+		ref->release(ref);
+		item->object = NULL;
+	}
+	mutex_unlock(&item->mutex);
+}
+EXPORT_SYMBOL(drm_global_item_unref);
+