third_party: Add the libsync library from Android

third_party/libsync/include/linux/sync.h

+/*
+ *  Copyright 2016 Google, Inc
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+#ifndef _UAPI_LINUX_SYNC_H
+#define _UAPI_LINUX_SYNC_H
+
+#include <linux/ioctl.h>
+#include <linux/types.h>
+
+/**
+ * struct sync_merge_data - data passed to merge ioctl
+ * @fd2:        file descriptor of second fence
+ * @name:       name of new fence
+ * @fence:      returns the fd of the new fence to userspace
+ */
+struct sync_merge_data {
+        __s32   fd2; /* fd of second fence */
+        char    name[32]; /* name of new fence */
+        __s32   fence; /* fd on newly created fence */
+};
+
+/**
+ * struct sync_pt_info - detailed sync_pt information
+ * @len:                length of sync_pt_info including any driver_data
+ * @obj_name:           name of parent sync_timeline
+ * @driver_name:        name of driver implementing the parent
+ * @status:             status of the sync_pt 0:active 1:signaled <0:error
+ * @timestamp_ns:       timestamp of status change in nanoseconds
+ * @driver_data:        any driver dependent data
+ */
+struct sync_pt_info {
+        __u32   len;
+        char    obj_name[32];
+        char    driver_name[32];
+        __s32   status;
+        __u64   timestamp_ns;
+
+        __u8    driver_data[0];
+};
+
+/**
+ * struct sync_fence_info_data - data returned from fence info ioctl
+ * @len:        ioctl caller writes the size of the buffer its passing in.
+ *              ioctl returns length of sync_fence_data returned to userspace
+ *              including pt_info.
+ * @name:       name of fence
+ * @status:     status of fence. 1: signaled 0:active <0:error
+ * @pt_info:    a sync_pt_info struct for every sync_pt in the fence
+ */
+struct sync_fence_info_data {
+        __u32   len;
+        char    name[32];
+        __s32   status;
+
+        __u8    pt_info[0];
+};
+
+#define SYNC_IOC_MAGIC          '>'
+
+/**
+ * DOC: SYNC_IOC_WAIT - wait for a fence to signal
+ *
+ * pass timeout in milliseconds.  Waits indefinitely timeout < 0.
+ */
+#define SYNC_IOC_WAIT           _IOW(SYNC_IOC_MAGIC, 0, __s32)
+
+/**
+ * DOC: SYNC_IOC_MERGE - merge two fences
+ *
+ * Takes a struct sync_merge_data.  Creates a new fence containing copies of
+ * the sync_pts in both the calling fd and sync_merge_data.fd2.  Returns the
+ * new fence's fd in sync_merge_data.fence
+ */
+#define SYNC_IOC_MERGE          _IOWR(SYNC_IOC_MAGIC, 1, struct sync_merge_data)
+
+/**
+ * DOC: SYNC_IOC_FENCE_INFO - get detailed information on a fence
+ *
+ * Takes a struct sync_fence_info_data with extra space allocated for pt_info.
+ * Caller should write the size of the buffer into len.  On return, len is
+ * updated to reflect the total size of the sync_fence_info_data including
+ * pt_info.
+ *
+ * pt_info is a buffer containing sync_pt_infos for every sync_pt in the fence.
+ * To iterate over the sync_pt_infos, use the sync_pt_info.len field.
+ */
+#define SYNC_IOC_FENCE_INFO     _IOWR(SYNC_IOC_MAGIC, 2,\
+        struct sync_fence_info_data)
+
+#endif /* _UAPI_LINUX_SYNC_H */