compat linux: import completion from linux 4.18

This patch port the file include/linux/completion.h
from linux 4.18 to u-boot. It define the structure
but all the function are stubbed.

Signed-off-by: Philippe Reynes <philippe.reynes@softathome.com>

include/linux/completion.h

@@ -0,0 +1,173 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LINUX_COMPLETION_H
+#define __LINUX_COMPLETION_H
+
+/*
+ * (C) Copyright 2001 Linus Torvalds
+ *
+ * Atomic wait-for-completion handler data structures.
+ * See kernel/sched/completion.c for details.
+ */
+#ifndef __UBOOT__
+#include <linux/wait.h>
+#endif /* __UBOOT__ */
+
+/*
+ * struct completion - structure used to maintain state for a "completion"
+ *
+ * This is the opaque structure used to maintain the state for a "completion".
+ * Completions currently use a FIFO to queue threads that have to wait for
+ * the "completion" event.
+ *
+ * See also:  complete(), wait_for_completion() (and friends _timeout,
+ * _interruptible, _interruptible_timeout, and _killable), init_completion(),
+ * reinit_completion(), and macros DECLARE_COMPLETION(),
+ * DECLARE_COMPLETION_ONSTACK().
+ */
+struct completion {
+	unsigned int done;
+#ifndef __UBOOT__
+	wait_queue_head_t wait;
+#endif /* __UBOOT__ */
+};
+
+#define init_completion_map(x, m) __init_completion(x)
+#define init_completion(x) __init_completion(x)
+static inline void complete_acquire(struct completion *x) {}
+static inline void complete_release(struct completion *x) {}
+
+#define COMPLETION_INITIALIZER(work) \
+	{ 0, __WAIT_QUEUE_HEAD_INITIALIZER((work).wait) }
+
+#define COMPLETION_INITIALIZER_ONSTACK_MAP(work, map) \
+	(*({ init_completion_map(&(work), &(map)); &(work); }))
+
+#define COMPLETION_INITIALIZER_ONSTACK(work) \
+	(*({ init_completion(&work); &work; }))
+
+/**
+ * DECLARE_COMPLETION - declare and initialize a completion structure
+ * @work:  identifier for the completion structure
+ *
+ * This macro declares and initializes a completion structure. Generally used
+ * for static declarations. You should use the _ONSTACK variant for automatic
+ * variables.
+ */
+#define DECLARE_COMPLETION(work) \
+	struct completion work = COMPLETION_INITIALIZER(work)
+
+/*
+ * Lockdep needs to run a non-constant initializer for on-stack
+ * completions - so we use the _ONSTACK() variant for those that
+ * are on the kernel stack:
+ */
+/**
+ * DECLARE_COMPLETION_ONSTACK - declare and initialize a completion structure
+ * @work:  identifier for the completion structure
+ *
+ * This macro declares and initializes a completion structure on the kernel
+ * stack.
+ */
+#ifdef CONFIG_LOCKDEP
+# define DECLARE_COMPLETION_ONSTACK(work) \
+	struct completion work = COMPLETION_INITIALIZER_ONSTACK(work)
+# define DECLARE_COMPLETION_ONSTACK_MAP(work, map) \
+	struct completion work = COMPLETION_INITIALIZER_ONSTACK_MAP(work, map)
+#else
+# define DECLARE_COMPLETION_ONSTACK(work) DECLARE_COMPLETION(work)
+# define DECLARE_COMPLETION_ONSTACK_MAP(work, map) DECLARE_COMPLETION(work)
+#endif
+
+/**
+ * init_completion - Initialize a dynamically allocated completion
+ * @x:  pointer to completion structure that is to be initialized
+ *
+ * This inline function will initialize a dynamically created completion
+ * structure.
+ */
+static inline void __init_completion(struct completion *x)
+{
+	x->done = 0;
+#ifndef __UBOOT__
+	init_waitqueue_head(&x->wait);
+#endif /* __UBOOT__ */
+}
+
+/**
+ * reinit_completion - reinitialize a completion structure
+ * @x:  pointer to completion structure that is to be reinitialized
+ *
+ * This inline function should be used to reinitialize a completion structure so it can
+ * be reused. This is especially important after complete_all() is used.
+ */
+static inline void reinit_completion(struct completion *x)
+{
+	x->done = 0;
+}
+
+#ifndef __UBOOT__
+extern void wait_for_completion(struct completion *);
+extern void wait_for_completion_io(struct completion *);
+extern int wait_for_completion_interruptible(struct completion *x);
+extern int wait_for_completion_killable(struct completion *x);
+extern unsigned long wait_for_completion_timeout(struct completion *x,
+						   unsigned long timeout);
+extern unsigned long wait_for_completion_io_timeout(struct completion *x,
+						    unsigned long timeout);
+extern long wait_for_completion_interruptible_timeout(
+	struct completion *x, unsigned long timeout);
+extern long wait_for_completion_killable_timeout(
+	struct completion *x, unsigned long timeout);
+extern bool try_wait_for_completion(struct completion *x);
+extern bool completion_done(struct completion *x);
+
+extern void complete(struct completion *);
+extern void complete_all(struct completion *);
+
+#else /* __UBOOT __ */
+
+#define wait_for_completion(x)		do {} while (0)
+#define wait_for_completion_io(x)	do {} while (0)
+
+inline int wait_for_completion_interruptible(struct completion *x)
+{
+	return 1;
+}
+inline int wait_for_completion_killable(struct completion *x)
+{
+	return 1;
+}
+inline unsigned long wait_for_completion_timeout(struct completion *x,
+						 unsigned long timeout)
+{
+	return 1;
+}
+inline unsigned long wait_for_completion_io_timeout(struct completion *x,
+						    unsigned long timeout)
+{
+	return 1;
+}
+inline long wait_for_completion_interruptible_timeout(struct completion *x,
+						      unsigned long timeout)
+{
+	return 1;
+}
+inline long wait_for_completion_killable_timeout(struct completion *x,
+						 unsigned long timeout)
+{
+	return 1;
+}
+inline bool try_wait_for_completion(struct completion *x)
+{
+	return 1;
+}
+inline bool completion_done(struct completion *x)
+{
+	return 1;
+}
+
+#define complete(x)		do {} while (0)
+#define complete_all(x)		do {} while (0)
+#endif /* __UBOOT__ */
+
+#endif