[PATCH libdrm] add libsync.h helper

[Rob Clark]

From: Rob Clark <robclark at freedesktop.org>

Rather than cut/pasting these couple ioctl wrappers everywhere, just
stuff them as static-inline into a header.

Signed-off-by: Rob Clark <robclark at freedesktop.org>
---
This is probably mostly used from mesa, but some drivers, test apps, etc
may also want to use it from libdrm.

 Makefile.sources |  1 +
 libsync.h        | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 75 insertions(+)
 create mode 100644 libsync.h

diff --git a/Makefile.sources b/Makefile.sources
index a57036a..10aa1d0 100644
--- a/Makefile.sources
+++ b/Makefile.sources
@@ -13,6 +13,7 @@ LIBDRM_FILES := \
 	util_math.h
 
 LIBDRM_H_FILES := \
+	libsync.h \
 	xf86drm.h \
 	xf86drmMode.h
 
diff --git a/libsync.h b/libsync.h
new file mode 100644
index 0000000..fc23b7f
--- /dev/null
+++ b/libsync.h
@@ -0,0 +1,74 @@
+/*
+ *  sync abstraction
+ *  Copyright 2015-2016 Collabora Ltd.
+ *
+ *  Based on the implementation from the Android Open Source Project,
+ *
+ *  Copyright 2012 Google, 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, 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.
+ */
+
+#ifndef _LIBSYNC_H
+#define _LIBSYNC_H
+
+#include <stdint.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/poll.h>
+
+// todo prob should just #include <linux/sync_file.h> ?
+struct sync_merge_data {
+	char	name[32];
+	int32_t	fd2;
+	int32_t	fence;
+	uint32_t	flags;
+	uint32_t	pad;
+};
+#define SYNC_IOC_MAGIC		'>'
+#define SYNC_IOC_MERGE		_IOWR(SYNC_IOC_MAGIC, 3, struct sync_merge_data)
+
+
+
+static inline int sync_wait(int fd, int timeout)
+{
+	struct pollfd fds;
+
+	fds.fd = fd;
+	fds.events = POLLIN | POLLERR;
+	return poll(&fds, 1, timeout);
+}
+
+static inline int sync_merge(const char *name, int fd1, int fd2)
+{
+	struct sync_merge_data data = {};
+	int err;
+
+	data.fd2 = fd2;
+	strncpy(data.name, name, sizeof(data.name) - 1);
+	data.name[sizeof(data.name) - 1] = '\0';
+
+	err = ioctl(fd1, SYNC_IOC_MERGE, &data);
+	if (err < 0)
+		return err;
+
+	return data.fence;
+}
+
+#endif
-- 
2.7.4