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 * poll_timeout_us - Periodically poll and perform an operation until
18 * a condition is met or a timeout occurs
19 *
20 * @op: Operation
21 * @cond: Break condition
22 * @sleep_us: Maximum time to sleep between operations in us (0 tight-loops).
23 * Please read usleep_range() function description for details and
24 * limitations.
25 * @timeout_us: Timeout in us, 0 means never timeout
26 * @sleep_before_op: if it is true, sleep @sleep_us before operation.
27 *
28 * When available, you'll probably want to use one of the specialized
29 * macros defined below rather than this macro directly.
30 *
31 * Returns: 0 on success and -ETIMEDOUT upon a timeout. Must not
32 * be called from atomic context if sleep_us or timeout_us are used.
33 */
34#define poll_timeout_us(op, cond, sleep_us, timeout_us, sleep_before_op) \
35({ \
36 u64 __timeout_us = (timeout_us); \
37 unsigned long __sleep_us = (sleep_us); \
38 ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \
39 int ___ret; \
40 might_sleep_if((__sleep_us) != 0); \
41 if ((sleep_before_op) && __sleep_us) \
42 usleep_range((__sleep_us >> 2) + 1, __sleep_us); \
43 for (;;) { \
44 bool __expired = __timeout_us && \
45 ktime_compare(ktime_get(), __timeout) > 0; \
46 /* guarantee 'op' and 'cond' are evaluated after timeout expired */ \
47 barrier(); \
48 op; \
49 if (cond) { \
50 ___ret = 0; \
51 break; \
52 } \
53 if (__expired) { \
54 ___ret = -ETIMEDOUT; \
55 break; \
56 } \
57 if (__sleep_us) \
58 usleep_range((__sleep_us >> 2) + 1, __sleep_us); \
59 cpu_relax(); \
60 } \
61 ___ret; \
62})
63
64/**
65 * poll_timeout_us_atomic - Periodically poll and perform an operation until
66 * a condition is met or a timeout occurs
67 *
68 * @op: Operation
69 * @cond: Break condition
70 * @delay_us: Time to udelay between operations in us (0 tight-loops).
71 * Please read udelay() function description for details and
72 * limitations.
73 * @timeout_us: Timeout in us, 0 means never timeout
74 * @delay_before_op: if it is true, delay @delay_us before operation.
75 *
76 * This macro does not rely on timekeeping. Hence it is safe to call even when
77 * timekeeping is suspended, at the expense of an underestimation of wall clock
78 * time, which is rather minimal with a non-zero delay_us.
79 *
80 * When available, you'll probably want to use one of the specialized
81 * macros defined below rather than this macro directly.
82 *
83 * Returns: 0 on success and -ETIMEDOUT upon a timeout.
84 */
85#define poll_timeout_us_atomic(op, cond, delay_us, timeout_us, \
86 delay_before_op) \
87({ \
88 u64 __timeout_us = (timeout_us); \
89 s64 __left_ns = __timeout_us * NSEC_PER_USEC; \
90 unsigned long __delay_us = (delay_us); \
91 u64 __delay_ns = __delay_us * NSEC_PER_USEC; \
92 int ___ret; \
93 if ((delay_before_op) && __delay_us) { \
94 udelay(__delay_us); \
95 if (__timeout_us) \
96 __left_ns -= __delay_ns; \
97 } \
98 for (;;) { \
99 bool __expired = __timeout_us && __left_ns < 0; \
100 /* guarantee 'op' and 'cond' are evaluated after timeout expired */ \
101 barrier(); \
102 op; \
103 if (cond) { \
104 ___ret = 0; \
105 break; \
106 } \
107 if (__expired) { \
108 ___ret = -ETIMEDOUT; \
109 break; \
110 } \
111 if (__delay_us) { \
112 udelay(__delay_us); \
113 if (__timeout_us) \
114 __left_ns -= __delay_ns; \
115 } \
116 cpu_relax(); \
117 if (__timeout_us) \
118 __left_ns--; \
119 } \
120 ___ret; \
121})
122
123/**
124 * read_poll_timeout - Periodically poll an address until a condition is
125 * met or a timeout occurs
126 * @op: accessor function (takes @args as its arguments)
127 * @val: Variable to read the value into
128 * @cond: Break condition (usually involving @val)
129 * @sleep_us: Maximum time to sleep between reads in us (0 tight-loops). Please
130 * read usleep_range() function description for details and
131 * limitations.
132 * @timeout_us: Timeout in us, 0 means never timeout
133 * @sleep_before_read: if it is true, sleep @sleep_us before read.
134 * @args: arguments for @op poll
135 *
136 * When available, you'll probably want to use one of the specialized
137 * macros defined below rather than this macro directly.
138 *
139 * Returns: 0 on success and -ETIMEDOUT upon a timeout. In either
140 * case, the last read value at @args is stored in @val. Must not
141 * be called from atomic context if sleep_us or timeout_us are used.
142 */
143#define read_poll_timeout(op, val, cond, sleep_us, timeout_us, \
144 sleep_before_read, args...) \
145 poll_timeout_us((val) = op(args), cond, sleep_us, timeout_us, sleep_before_read)
146
147/**
148 * read_poll_timeout_atomic - Periodically poll an address until a condition is
149 * met or a timeout occurs
150 * @op: accessor function (takes @args as its arguments)
151 * @val: Variable to read the value into
152 * @cond: Break condition (usually involving @val)
153 * @delay_us: Time to udelay between reads in us (0 tight-loops). Please
154 * read udelay() function description for details and
155 * limitations.
156 * @timeout_us: Timeout in us, 0 means never timeout
157 * @delay_before_read: if it is true, delay @delay_us before read.
158 * @args: arguments for @op poll
159 *
160 * This macro does not rely on timekeeping. Hence it is safe to call even when
161 * timekeeping is suspended, at the expense of an underestimation of wall clock
162 * time, which is rather minimal with a non-zero delay_us.
163 *
164 * When available, you'll probably want to use one of the specialized
165 * macros defined below rather than this macro directly.
166 *
167 * Returns: 0 on success and -ETIMEDOUT upon a timeout. In either
168 * case, the last read value at @args is stored in @val.
169 */
170#define read_poll_timeout_atomic(op, val, cond, sleep_us, timeout_us, \
171 sleep_before_read, args...) \
172 poll_timeout_us_atomic((val) = op(args), cond, sleep_us, timeout_us, sleep_before_read)
173
174/**
175 * readx_poll_timeout - Periodically poll an address until a condition is met or a timeout occurs
176 * @op: accessor function (takes @addr as its only argument)
177 * @addr: Address to poll
178 * @val: Variable to read the value into
179 * @cond: Break condition (usually involving @val)
180 * @sleep_us: Maximum time to sleep between reads in us (0 tight-loops). Please
181 * read usleep_range() function description for details and
182 * limitations.
183 * @timeout_us: Timeout in us, 0 means never timeout
184 *
185 * When available, you'll probably want to use one of the specialized
186 * macros defined below rather than this macro directly.
187 *
188 * Returns: 0 on success and -ETIMEDOUT upon a timeout. In either
189 * case, the last read value at @addr is stored in @val. Must not
190 * be called from atomic context if sleep_us or timeout_us are used.
191 */
192#define readx_poll_timeout(op, addr, val, cond, sleep_us, timeout_us) \
193 read_poll_timeout(op, val, cond, sleep_us, timeout_us, false, addr)
194
195/**
196 * readx_poll_timeout_atomic - Periodically poll an address until a condition is met or a timeout occurs
197 * @op: accessor function (takes @addr as its only argument)
198 * @addr: Address to poll
199 * @val: Variable to read the value into
200 * @cond: Break condition (usually involving @val)
201 * @delay_us: Time to udelay between reads in us (0 tight-loops). Please
202 * read udelay() function description for details and
203 * limitations.
204 * @timeout_us: Timeout in us, 0 means never timeout
205 *
206 * When available, you'll probably want to use one of the specialized
207 * macros defined below rather than this macro directly.
208 *
209 * Returns: 0 on success and -ETIMEDOUT upon a timeout. In either
210 * case, the last read value at @addr is stored in @val.
211 */
212#define readx_poll_timeout_atomic(op, addr, val, cond, delay_us, timeout_us) \
213 read_poll_timeout_atomic(op, val, cond, delay_us, timeout_us, false, addr)
214
215#define readb_poll_timeout(addr, val, cond, delay_us, timeout_us) \
216 readx_poll_timeout(readb, addr, val, cond, delay_us, timeout_us)
217
218#define readb_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
219 readx_poll_timeout_atomic(readb, addr, val, cond, delay_us, timeout_us)
220
221#define readw_poll_timeout(addr, val, cond, delay_us, timeout_us) \
222 readx_poll_timeout(readw, addr, val, cond, delay_us, timeout_us)
223
224#define readw_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
225 readx_poll_timeout_atomic(readw, addr, val, cond, delay_us, timeout_us)
226
227#define readl_poll_timeout(addr, val, cond, delay_us, timeout_us) \
228 readx_poll_timeout(readl, addr, val, cond, delay_us, timeout_us)
229
230#define readl_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
231 readx_poll_timeout_atomic(readl, addr, val, cond, delay_us, timeout_us)
232
233#define readq_poll_timeout(addr, val, cond, delay_us, timeout_us) \
234 readx_poll_timeout(readq, addr, val, cond, delay_us, timeout_us)
235
236#define readq_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
237 readx_poll_timeout_atomic(readq, addr, val, cond, delay_us, timeout_us)
238
239#define readb_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
240 readx_poll_timeout(readb_relaxed, addr, val, cond, delay_us, timeout_us)
241
242#define readb_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
243 readx_poll_timeout_atomic(readb_relaxed, addr, val, cond, delay_us, timeout_us)
244
245#define readw_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
246 readx_poll_timeout(readw_relaxed, addr, val, cond, delay_us, timeout_us)
247
248#define readw_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
249 readx_poll_timeout_atomic(readw_relaxed, addr, val, cond, delay_us, timeout_us)
250
251#define readl_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
252 readx_poll_timeout(readl_relaxed, addr, val, cond, delay_us, timeout_us)
253
254#define readl_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
255 readx_poll_timeout_atomic(readl_relaxed, addr, val, cond, delay_us, timeout_us)
256
257#define readq_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
258 readx_poll_timeout(readq_relaxed, addr, val, cond, delay_us, timeout_us)
259
260#define readq_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
261 readx_poll_timeout_atomic(readq_relaxed, addr, val, cond, delay_us, timeout_us)
262
263#endif /* _LINUX_IOPOLL_H */
264