Include nvgpu headers

These are needed to build on NVIDIA's Jetson boards for the time
being. Only a couple structs are required, so it should be fairly
easy to remove this dependency at some point in the future.

1 files changed, 87 insertions, 0 deletions

diff --git a/include/nvgpu/kref.h b/include/nvgpu/kref.h
new file mode 100644
index 0000000..486040e
--- /dev/null
+++ b/include/nvgpu/kref.h
@@ -0,0 +1,87 @@
+/*
+ * Copyright (c) 2017-2018, NVIDIA CORPORATION.  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, sublicense,
+ * 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 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 NONINFRINGEMENT.  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.
+ */
+
+/*
+ * The following structure is used for reference counting of objects in nvgpu.
+ */
+#ifndef NVGPU_KREF_H
+#define NVGPU_KREF_H
+
+#include <nvgpu/atomic.h>
+
+struct nvgpu_ref {
+        nvgpu_atomic_t refcount;
+};
+
+/*
+ * Initialize object.
+ * @ref: the nvgpu_ref object to initialize
+ */
+static inline void nvgpu_ref_init(struct nvgpu_ref *ref)
+{
+        nvgpu_atomic_set(&ref->refcount, 1);
+}
+
+/*
+ * Increment reference count for the object
+ * @ref: the nvgpu_ref object
+ */
+static inline void nvgpu_ref_get(struct nvgpu_ref *ref)
+{
+        nvgpu_atomic_inc(&ref->refcount);
+}
+
+/*
+ * Decrement reference count for the object and call release() if it becomes
+ * zero.
+ * @ref: the nvgpu_ref object
+ * @release: pointer to the function that would be invoked to clean up the
+ *      object when the reference count becomes zero, i.e. the last
+ *      reference corresponding to this object is removed.
+ * Return 1 if object was removed, otherwise return 0. The user should not
+ * make any assumptions about the status of the object in the memory when
+ * the function returns 0 and should only use it to know that there are no
+ * further references to this object.
+ */
+static inline int nvgpu_ref_put(struct nvgpu_ref *ref,
+                void (*release)(struct nvgpu_ref *r))
+{
+        if (nvgpu_atomic_sub_and_test(1, &ref->refcount)) {
+                if (release != NULL) {
+                        release(ref);
+                }
+                return 1;
+        }
+        return 0;
+}
+
+/*
+ * Increment reference count for the object unless it is zero.
+ * @ref: the nvgpu_ref object
+ * Return non-zero if the increment succeeds, Otherwise return 0.
+ */
+static inline int __must_check nvgpu_ref_get_unless_zero(struct nvgpu_ref *ref)
+{
+        return nvgpu_atomic_add_unless(&ref->refcount, 1, 0);
+}
+
+#endif /* NVGPU_KREF_H */