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1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Copyright (c) 2012-2014 The Linux Foundation. All rights reserved.
4 */
5
6#ifndef _LINUX_IOPOLL_H
7#define _LINUX_IOPOLL_H
8
9#include <linux/kernel.h>
10#include <linux/types.h>
11#include <linux/ktime.h>
12#include <linux/delay.h>
13#include <linux/errno.h>
14#include <linux/io.h>
15
16/**
17 * read_poll_timeout - Periodically poll an address until a condition is
18 * met or a timeout occurs
19 * @op: accessor function (takes @args as its arguments)
20 * @val: Variable to read the value into
21 * @cond: Break condition (usually involving @val)
22 * @sleep_us: Maximum time to sleep between reads in us (0
23 * tight-loops). Should be less than ~20ms since usleep_range
24 * is used (see Documentation/timers/timers-howto.rst).
25 * @timeout_us: Timeout in us, 0 means never timeout
26 * @sleep_before_read: if it is true, sleep @sleep_us before read.
27 * @args: arguments for @op poll
28 *
29 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either
30 * case, the last read value at @args is stored in @val. Must not
31 * be called from atomic context if sleep_us or timeout_us are used.
32 *
33 * When available, you'll probably want to use one of the specialized
34 * macros defined below rather than this macro directly.
35 */
36#define read_poll_timeout(op, val, cond, sleep_us, timeout_us, \
37 sleep_before_read, args...) \
38({ \
39 u64 __timeout_us = (timeout_us); \
40 unsigned long __sleep_us = (sleep_us); \
41 ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \
42 might_sleep_if((__sleep_us) != 0); \
43 if (sleep_before_read && __sleep_us) \
44 usleep_range((__sleep_us >> 2) + 1, __sleep_us); \
45 for (;;) { \
46 (val) = op(args); \
47 if (cond) \
48 break; \
49 if (__timeout_us && \
50 ktime_compare(ktime_get(), __timeout) > 0) { \
51 (val) = op(args); \
52 break; \
53 } \
54 if (__sleep_us) \
55 usleep_range((__sleep_us >> 2) + 1, __sleep_us); \
56 } \
57 (cond) ? 0 : -ETIMEDOUT; \
58})
59
60/**
61 * readx_poll_timeout - Periodically poll an address until a condition is met or a timeout occurs
62 * @op: accessor function (takes @addr as its only argument)
63 * @addr: Address to poll
64 * @val: Variable to read the value into
65 * @cond: Break condition (usually involving @val)
66 * @sleep_us: Maximum time to sleep between reads in us (0
67 * tight-loops). Should be less than ~20ms since usleep_range
68 * is used (see Documentation/timers/timers-howto.rst).
69 * @timeout_us: Timeout in us, 0 means never timeout
70 *
71 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either
72 * case, the last read value at @addr is stored in @val. Must not
73 * be called from atomic context if sleep_us or timeout_us are used.
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(op, addr, val, cond, sleep_us, timeout_us) \
79 read_poll_timeout(op, val, cond, sleep_us, timeout_us, false, addr)
80
81/**
82 * readx_poll_timeout_atomic - Periodically poll an address until a condition is met or a timeout occurs
83 * @op: accessor function (takes @addr as its only argument)
84 * @addr: Address to poll
85 * @val: Variable to read the value into
86 * @cond: Break condition (usually involving @val)
87 * @delay_us: Time to udelay between reads in us (0 tight-loops). Should
88 * be less than ~10us since udelay is used (see
89 * Documentation/timers/timers-howto.rst).
90 * @timeout_us: Timeout in us, 0 means never timeout
91 *
92 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either
93 * case, the last read value at @addr is stored in @val.
94 *
95 * When available, you'll probably want to use one of the specialized
96 * macros defined below rather than this macro directly.
97 */
98#define readx_poll_timeout_atomic(op, addr, val, cond, delay_us, timeout_us) \
99({ \
100 u64 __timeout_us = (timeout_us); \
101 unsigned long __delay_us = (delay_us); \
102 ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \
103 for (;;) { \
104 (val) = op(addr); \
105 if (cond) \
106 break; \
107 if (__timeout_us && \
108 ktime_compare(ktime_get(), __timeout) > 0) { \
109 (val) = op(addr); \
110 break; \
111 } \
112 if (__delay_us) \
113 udelay(__delay_us); \
114 } \
115 (cond) ? 0 : -ETIMEDOUT; \
116})
117
118
119#define readb_poll_timeout(addr, val, cond, delay_us, timeout_us) \
120 readx_poll_timeout(readb, addr, val, cond, delay_us, timeout_us)
121
122#define readb_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
123 readx_poll_timeout_atomic(readb, addr, val, cond, delay_us, timeout_us)
124
125#define readw_poll_timeout(addr, val, cond, delay_us, timeout_us) \
126 readx_poll_timeout(readw, addr, val, cond, delay_us, timeout_us)
127
128#define readw_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
129 readx_poll_timeout_atomic(readw, addr, val, cond, delay_us, timeout_us)
130
131#define readl_poll_timeout(addr, val, cond, delay_us, timeout_us) \
132 readx_poll_timeout(readl, addr, val, cond, delay_us, timeout_us)
133
134#define readl_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
135 readx_poll_timeout_atomic(readl, addr, val, cond, delay_us, timeout_us)
136
137#define readq_poll_timeout(addr, val, cond, delay_us, timeout_us) \
138 readx_poll_timeout(readq, addr, val, cond, delay_us, timeout_us)
139
140#define readq_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
141 readx_poll_timeout_atomic(readq, addr, val, cond, delay_us, timeout_us)
142
143#define readb_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
144 readx_poll_timeout(readb_relaxed, addr, val, cond, delay_us, timeout_us)
145
146#define readb_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
147 readx_poll_timeout_atomic(readb_relaxed, addr, val, cond, delay_us, timeout_us)
148
149#define readw_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
150 readx_poll_timeout(readw_relaxed, addr, val, cond, delay_us, timeout_us)
151
152#define readw_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
153 readx_poll_timeout_atomic(readw_relaxed, addr, val, cond, delay_us, timeout_us)
154
155#define readl_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
156 readx_poll_timeout(readl_relaxed, addr, val, cond, delay_us, timeout_us)
157
158#define readl_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
159 readx_poll_timeout_atomic(readl_relaxed, addr, val, cond, delay_us, timeout_us)
160
161#define readq_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
162 readx_poll_timeout(readq_relaxed, addr, val, cond, delay_us, timeout_us)
163
164#define readq_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
165 readx_poll_timeout_atomic(readq_relaxed, addr, val, cond, delay_us, timeout_us)
166
167#endif /* _LINUX_IOPOLL_H */