1 /* SPDX-License-Identifier: GPL-2.0-only */
3 * Copyright (c) 2012-2014 The Linux Foundation. All rights reserved.
6 #ifndef _LINUX_IOPOLL_H
7 #define _LINUX_IOPOLL_H
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>
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
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.
33 * When available, you'll probably want to use one of the specialized
34 * macros defined below rather than this macro directly.
36 #define read_poll_timeout(op, val, cond, sleep_us, timeout_us, \
37 sleep_before_read, args...) \
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); \
50 ktime_compare(ktime_get(), __timeout) > 0) { \
55 usleep_range((__sleep_us >> 2) + 1, __sleep_us); \
58 (cond) ? 0 : -ETIMEDOUT; \
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
74 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either
75 * case, the last read value at @args is stored in @val.
77 * When available, you'll probably want to use one of the specialized
78 * macros defined below rather than this macro directly.
80 #define read_poll_timeout_atomic(op, val, cond, delay_us, timeout_us, \
81 delay_before_read, args...) \
83 u64 __timeout_us = (timeout_us); \
84 unsigned long __delay_us = (delay_us); \
85 ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \
86 if (delay_before_read && __delay_us) \
93 ktime_compare(ktime_get(), __timeout) > 0) { \
101 (cond) ? 0 : -ETIMEDOUT; \
105 * readx_poll_timeout - Periodically poll an address until a condition is met or a timeout occurs
106 * @op: accessor function (takes @addr as its only argument)
107 * @addr: Address to poll
108 * @val: Variable to read the value into
109 * @cond: Break condition (usually involving @val)
110 * @sleep_us: Maximum time to sleep between reads in us (0
111 * tight-loops). Should be less than ~20ms since usleep_range
112 * is used (see Documentation/timers/timers-howto.rst).
113 * @timeout_us: Timeout in us, 0 means never timeout
115 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either
116 * case, the last read value at @addr is stored in @val. Must not
117 * be called from atomic context if sleep_us or timeout_us are used.
119 * When available, you'll probably want to use one of the specialized
120 * macros defined below rather than this macro directly.
122 #define readx_poll_timeout(op, addr, val, cond, sleep_us, timeout_us) \
123 read_poll_timeout(op, val, cond, sleep_us, timeout_us, false, addr)
126 * readx_poll_timeout_atomic - Periodically poll an address until a condition is met or a timeout occurs
127 * @op: accessor function (takes @addr as its only argument)
128 * @addr: Address to poll
129 * @val: Variable to read the value into
130 * @cond: Break condition (usually involving @val)
131 * @delay_us: Time to udelay between reads in us (0 tight-loops). Should
132 * be less than ~10us since udelay is used (see
133 * Documentation/timers/timers-howto.rst).
134 * @timeout_us: Timeout in us, 0 means never timeout
136 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either
137 * case, the last read value at @addr is stored in @val.
139 * When available, you'll probably want to use one of the specialized
140 * macros defined below rather than this macro directly.
142 #define readx_poll_timeout_atomic(op, addr, val, cond, delay_us, timeout_us) \
143 read_poll_timeout_atomic(op, val, cond, delay_us, timeout_us, false, addr)
145 #define readb_poll_timeout(addr, val, cond, delay_us, timeout_us) \
146 readx_poll_timeout(readb, addr, val, cond, delay_us, timeout_us)
148 #define readb_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
149 readx_poll_timeout_atomic(readb, addr, val, cond, delay_us, timeout_us)
151 #define readw_poll_timeout(addr, val, cond, delay_us, timeout_us) \
152 readx_poll_timeout(readw, addr, val, cond, delay_us, timeout_us)
154 #define readw_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
155 readx_poll_timeout_atomic(readw, addr, val, cond, delay_us, timeout_us)
157 #define readl_poll_timeout(addr, val, cond, delay_us, timeout_us) \
158 readx_poll_timeout(readl, addr, val, cond, delay_us, timeout_us)
160 #define readl_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
161 readx_poll_timeout_atomic(readl, addr, val, cond, delay_us, timeout_us)
163 #define readq_poll_timeout(addr, val, cond, delay_us, timeout_us) \
164 readx_poll_timeout(readq, addr, val, cond, delay_us, timeout_us)
166 #define readq_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
167 readx_poll_timeout_atomic(readq, addr, val, cond, delay_us, timeout_us)
169 #define readb_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
170 readx_poll_timeout(readb_relaxed, addr, val, cond, delay_us, timeout_us)
172 #define readb_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
173 readx_poll_timeout_atomic(readb_relaxed, addr, val, cond, delay_us, timeout_us)
175 #define readw_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
176 readx_poll_timeout(readw_relaxed, addr, val, cond, delay_us, timeout_us)
178 #define readw_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
179 readx_poll_timeout_atomic(readw_relaxed, addr, val, cond, delay_us, timeout_us)
181 #define readl_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
182 readx_poll_timeout(readl_relaxed, addr, val, cond, delay_us, timeout_us)
184 #define readl_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
185 readx_poll_timeout_atomic(readl_relaxed, addr, val, cond, delay_us, timeout_us)
187 #define readq_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
188 readx_poll_timeout(readq_relaxed, addr, val, cond, delay_us, timeout_us)
190 #define readq_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
191 readx_poll_timeout_atomic(readq_relaxed, addr, val, cond, delay_us, timeout_us)
193 #endif /* _LINUX_IOPOLL_H */