Signed-off-by: Andrey Smirnov <andrew.smir...@gmail.com>
---
 include/linux/iopoll.h | 69 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 69 insertions(+)
 create mode 100644 include/linux/iopoll.h

diff --git a/include/linux/iopoll.h b/include/linux/iopoll.h
new file mode 100644
index 000000000..6e8a6fd71
--- /dev/null
+++ b/include/linux/iopoll.h
@@ -0,0 +1,69 @@
+/*
+ * Copyright (c) 2012-2014 The Linux Foundation. All rights reserved.
+ *
+ * SPDX-License-Identifier:    GPL-2.0
+ */
+
+#ifndef _LINUX_IOPOLL_H
+#define _LINUX_IOPOLL_H
+
+#include <errno.h>
+#include <io.h>
+#include <clock.h>
+
+/**
+ * readx_poll_timeout - Periodically poll an address until a condition is met 
or a timeout occurs
+ * @op: accessor function (takes @addr as its only argument)
+ * @addr: Address to poll
+ * @val: Variable to read the value into
+ * @cond: Break condition (usually involving @val)
+ * @timeout_ns: Timeout in ns, 0 means never timeout
+ *
+ * Returns 0 on success and -ETIMEDOUT upon a timeout. In either
+ * case, the last read value at @addr is stored in @val.
+ *
+ * When available, you'll probably want to use one of the specialized
+ * macros defined below rather than this macro directly.
+ */
+#define readx_poll_timeout(op, addr, val, cond, timeout_ns)    \
+({ \
+       uint64_t start = get_time_ns(); \
+       for (;;) { \
+               (val) = op(addr); \
+               if (cond) \
+                       break; \
+               if (timeout_ns && \
+                   is_timeout(start, (timeout_ns))) {  \
+                       (val) = op(addr); \
+                       break; \
+               } \
+       } \
+       (cond) ? 0 : -ETIMEDOUT; \
+})
+
+
+#define readb_poll_timeout(addr, val, cond, timeout_us) \
+       readx_poll_timeout(readb, addr, val, cond, timeout_us)
+
+#define readw_poll_timeout(addr, val, cond, timeout_us) \
+       readx_poll_timeout(readw, addr, val, cond, timeout_us)
+
+#define readl_poll_timeout(addr, val, cond, timeout_us) \
+       readx_poll_timeout(readl, addr, val, cond, timeout_us)
+
+#define readq_poll_timeout(addr, val, cond, timeout_us) \
+       readx_poll_timeout(readq, addr, val, cond, timeout_us)
+
+#define readb_relaxed_poll_timeout(addr, val, cond, timeout_us) \
+       readx_poll_timeout(readb_relaxed, addr, val, cond, timeout_us)
+
+#define readw_relaxed_poll_timeout(addr, val, cond, timeout_us) \
+       readx_poll_timeout(readw_relaxed, addr, val, cond, timeout_us)
+
+#define readl_relaxed_poll_timeout(addr, val, cond, timeout_us) \
+       readx_poll_timeout(readl_relaxed, addr, val, cond, timeout_us)
+
+#define readq_relaxed_poll_timeout(addr, val, cond, timeout_us) \
+       readx_poll_timeout(readq_relaxed, addr, val, cond, timeout_us)
+
+#endif /* _LINUX_IOPOLL_H */
-- 
2.17.0


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