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 cpu_relax(); \
57 } \
58 (cond) ? 0 : -ETIMEDOUT; \
59 })
60
61 /**
62 * read_poll_timeout_atomic - Periodically poll an address until a condition is
63 * met or a timeout occurs
64 * @op: accessor function (takes @args as its arguments)
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.rst).
70 * @timeout_us: Timeout in us, 0 means never timeout
71 * @delay_before_read: if it is true, delay @delay_us before read.
72 * @args: arguments for @op poll
73 *
74 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either
75 * case, the last read value at @args is stored in @val.
76 *
77 * This macro does not rely on timekeeping. Hence it is safe to call even when
78 * timekeeping is suspended, at the expense of an underestimation of wall clock
79 * time, which is rather minimal with a non-zero delay_us.
80 *
81 * When available, you'll probably want to use one of the specialized
82 * macros defined below rather than this macro directly.
83 */
84 #define read_poll_timeout_atomic(op, val, cond, delay_us, timeout_us, \
85 delay_before_read, args...) \
86 ({ \
87 u64 __timeout_us = (timeout_us); \
88 s64 __left_ns = __timeout_us * NSEC_PER_USEC; \
89 unsigned long __delay_us = (delay_us); \
90 u64 __delay_ns = __delay_us * NSEC_PER_USEC; \
91 if (delay_before_read && __delay_us) { \
92 udelay(__delay_us); \
93 if (__timeout_us) \
94 __left_ns -= __delay_ns; \
95 } \
96 for (;;) { \
97 (val) = op(args); \
98 if (cond) \
99 break; \
100 if (__timeout_us && __left_ns < 0) { \
101 (val) = op(args); \
102 break; \
103 } \
104 if (__delay_us) { \
105 udelay(__delay_us); \
106 if (__timeout_us) \
107 __left_ns -= __delay_ns; \
108 } \
109 cpu_relax(); \
110 if (__timeout_us) \
111 __left_ns--; \
112 } \
113 (cond) ? 0 : -ETIMEDOUT; \
114 })
115
116 /**
117 * readx_poll_timeout - Periodically poll an address until a condition is met or a timeout occurs
118 * @op: accessor function (takes @addr as its only argument)
119 * @addr: Address to poll
120 * @val: Variable to read the value into
121 * @cond: Break condition (usually involving @val)
122 * @sleep_us: Maximum time to sleep between reads in us (0
123 * tight-loops). Should be less than ~20ms since usleep_range
124 * is used (see Documentation/timers/timers-howto.rst).
125 * @timeout_us: Timeout in us, 0 means never timeout
126 *
127 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either
128 * case, the last read value at @addr is stored in @val. Must not
129 * be called from atomic context if sleep_us or timeout_us are used.
130 *
131 * When available, you'll probably want to use one of the specialized
132 * macros defined below rather than this macro directly.
133 */
134 #define readx_poll_timeout(op, addr, val, cond, sleep_us, timeout_us) \
135 read_poll_timeout(op, val, cond, sleep_us, timeout_us, false, addr)
136
137 /**
138 * readx_poll_timeout_atomic - Periodically poll an address until a condition is met or a timeout occurs
139 * @op: accessor function (takes @addr as its only argument)
140 * @addr: Address to poll
141 * @val: Variable to read the value into
142 * @cond: Break condition (usually involving @val)
143 * @delay_us: Time to udelay between reads in us (0 tight-loops). Should
144 * be less than ~10us since udelay is used (see
145 * Documentation/timers/timers-howto.rst).
146 * @timeout_us: Timeout in us, 0 means never timeout
147 *
148 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either
149 * case, the last read value at @addr is stored in @val.
150 *
151 * When available, you'll probably want to use one of the specialized
152 * macros defined below rather than this macro directly.
153 */
154 #define readx_poll_timeout_atomic(op, addr, val, cond, delay_us, timeout_us) \
155 read_poll_timeout_atomic(op, val, cond, delay_us, timeout_us, false, addr)
156
157 #define readb_poll_timeout(addr, val, cond, delay_us, timeout_us) \
158 readx_poll_timeout(readb, addr, val, cond, delay_us, timeout_us)
159
160 #define readb_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
161 readx_poll_timeout_atomic(readb, addr, val, cond, delay_us, timeout_us)
162
163 #define readw_poll_timeout(addr, val, cond, delay_us, timeout_us) \
164 readx_poll_timeout(readw, addr, val, cond, delay_us, timeout_us)
165
166 #define readw_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
167 readx_poll_timeout_atomic(readw, addr, val, cond, delay_us, timeout_us)
168
169 #define readl_poll_timeout(addr, val, cond, delay_us, timeout_us) \
170 readx_poll_timeout(readl, addr, val, cond, delay_us, timeout_us)
171
172 #define readl_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
173 readx_poll_timeout_atomic(readl, addr, val, cond, delay_us, timeout_us)
174
175 #define readq_poll_timeout(addr, val, cond, delay_us, timeout_us) \
176 readx_poll_timeout(readq, addr, val, cond, delay_us, timeout_us)
177
178 #define readq_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
179 readx_poll_timeout_atomic(readq, addr, val, cond, delay_us, timeout_us)
180
181 #define readb_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
182 readx_poll_timeout(readb_relaxed, addr, val, cond, delay_us, timeout_us)
183
184 #define readb_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
185 readx_poll_timeout_atomic(readb_relaxed, addr, val, cond, delay_us, timeout_us)
186
187 #define readw_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
188 readx_poll_timeout(readw_relaxed, addr, val, cond, delay_us, timeout_us)
189
190 #define readw_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
191 readx_poll_timeout_atomic(readw_relaxed, addr, val, cond, delay_us, timeout_us)
192
193 #define readl_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
194 readx_poll_timeout(readl_relaxed, addr, val, cond, delay_us, timeout_us)
195
196 #define readl_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
197 readx_poll_timeout_atomic(readl_relaxed, addr, val, cond, delay_us, timeout_us)
198
199 #define readq_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
200 readx_poll_timeout(readq_relaxed, addr, val, cond, delay_us, timeout_us)
201
202 #define readq_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
203 readx_poll_timeout_atomic(readq_relaxed, addr, val, cond, delay_us, timeout_us)
204
205 #endif /* _LINUX_IOPOLL_H */
206
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