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