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 | |