1/*
2 * Copyright (c) 2012-2014 The Linux Foundation. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 and
6 * only version 2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11 * GNU General Public License for more details.
12 *
13 */
14
15#ifndef _LINUX_IOPOLL_H
16#define _LINUX_IOPOLL_H
17
18#include <linux/kernel.h>
19#include <linux/types.h>
20#include <linux/hrtimer.h>
21#include <linux/delay.h>
22#include <linux/errno.h>
23#include <linux/io.h>
24
25/**
26 * readx_poll_timeout - Periodically poll an address until a condition is met or a timeout occurs
27 * @op: accessor function (takes @addr as its only argument)
28 * @addr: Address to poll
29 * @val: Variable to read the value into
30 * @cond: Break condition (usually involving @val)
31 * @sleep_us: Maximum time to sleep between reads in us (0
32 *            tight-loops).  Should be less than ~20ms since usleep_range
33 *            is used (see Documentation/timers/timers-howto.txt).
34 * @timeout_us: Timeout in us, 0 means never timeout
35 *
36 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either
37 * case, the last read value at @addr is stored in @val. Must not
38 * be called from atomic context if sleep_us or timeout_us are used.
39 *
40 * When available, you'll probably want to use one of the specialized
41 * macros defined below rather than this macro directly.
42 */
43#define readx_poll_timeout(op, addr, val, cond, sleep_us, timeout_us)	\
44({ \
45	ktime_t timeout = ktime_add_us(ktime_get(), timeout_us); \
46	might_sleep_if(sleep_us); \
47	for (;;) { \
48		(val) = op(addr); \
49		if (cond) \
50			break; \
51		if (timeout_us && ktime_compare(ktime_get(), timeout) > 0) { \
52			(val) = op(addr); \
53			break; \
54		} \
55		if (sleep_us) \
56			usleep_range((sleep_us >> 2) + 1, sleep_us); \
57	} \
58	(cond) ? 0 : -ETIMEDOUT; \
59})
60
61/**
62 * readx_poll_timeout_atomic - Periodically poll an address until a condition is met or a timeout occurs
63 * @op: accessor function (takes @addr as its only argument)
64 * @addr: Address to poll
65 * @val: Variable to read the value into
66 * @cond: Break condition (usually involving @val)
67 * @delay_us: Time to udelay between reads in us (0 tight-loops).  Should
68 *            be less than ~10us since udelay is used (see
69 *            Documentation/timers/timers-howto.txt).
70 * @timeout_us: Timeout in us, 0 means never timeout
71 *
72 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either
73 * case, the last read value at @addr is stored in @val.
74 *
75 * When available, you'll probably want to use one of the specialized
76 * macros defined below rather than this macro directly.
77 */
78#define readx_poll_timeout_atomic(op, addr, val, cond, delay_us, timeout_us) \
79({ \
80	ktime_t timeout = ktime_add_us(ktime_get(), timeout_us); \
81	for (;;) { \
82		(val) = op(addr); \
83		if (cond) \
84			break; \
85		if (timeout_us && ktime_compare(ktime_get(), timeout) > 0) { \
86			(val) = op(addr); \
87			break; \
88		} \
89		if (delay_us) \
90			udelay(delay_us);	\
91	} \
92	(cond) ? 0 : -ETIMEDOUT; \
93})
94
95
96#define readb_poll_timeout(addr, val, cond, delay_us, timeout_us) \
97	readx_poll_timeout(readb, addr, val, cond, delay_us, timeout_us)
98
99#define readb_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
100	readx_poll_timeout_atomic(readb, addr, val, cond, delay_us, timeout_us)
101
102#define readw_poll_timeout(addr, val, cond, delay_us, timeout_us) \
103	readx_poll_timeout(readw, addr, val, cond, delay_us, timeout_us)
104
105#define readw_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
106	readx_poll_timeout_atomic(readw, addr, val, cond, delay_us, timeout_us)
107
108#define readl_poll_timeout(addr, val, cond, delay_us, timeout_us) \
109	readx_poll_timeout(readl, addr, val, cond, delay_us, timeout_us)
110
111#define readl_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
112	readx_poll_timeout_atomic(readl, addr, val, cond, delay_us, timeout_us)
113
114#define readq_poll_timeout(addr, val, cond, delay_us, timeout_us) \
115	readx_poll_timeout(readq, addr, val, cond, delay_us, timeout_us)
116
117#define readq_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
118	readx_poll_timeout_atomic(readq, addr, val, cond, delay_us, timeout_us)
119
120#define readb_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
121	readx_poll_timeout(readb_relaxed, addr, val, cond, delay_us, timeout_us)
122
123#define readb_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
124	readx_poll_timeout_atomic(readb_relaxed, addr, val, cond, delay_us, timeout_us)
125
126#define readw_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
127	readx_poll_timeout(readw_relaxed, addr, val, cond, delay_us, timeout_us)
128
129#define readw_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
130	readx_poll_timeout_atomic(readw_relaxed, addr, val, cond, delay_us, timeout_us)
131
132#define readl_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
133	readx_poll_timeout(readl_relaxed, addr, val, cond, delay_us, timeout_us)
134
135#define readl_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
136	readx_poll_timeout_atomic(readl_relaxed, addr, val, cond, delay_us, timeout_us)
137
138#define readq_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
139	readx_poll_timeout(readq_relaxed, addr, val, cond, delay_us, timeout_us)
140
141#define readq_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
142	readx_poll_timeout_atomic(readq_relaxed, addr, val, cond, delay_us, timeout_us)
143
144#endif /* _LINUX_IOPOLL_H */
145