1/*
2 * Copyright (c) 2012-2014 The Linux Foundation. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 and
6 * only version 2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 */
14
15#ifndef _LINUX_IOPOLL_H
16#define _LINUX_IOPOLL_H
17
18#include <linux/kernel.h>
19#include <linux/types.h>
20#include <linux/ktime.h>
21#include <linux/delay.h>
22#include <linux/errno.h>
23#include <linux/io.h>
24
25/**
26 * readx_poll_timeout - Periodically poll an address until a condition is met or a timeout occurs
27 * @op: accessor function (takes @addr as its only argument)
28 * @addr: Address to poll
29 * @val: Variable to read the value into
30 * @cond: Break condition (usually involving @val)
31 * @sleep_us: Maximum time to sleep between reads in us (0
32 * tight-loops). Should be less than ~20ms since usleep_range
33 * is used (see Documentation/timers/timers-howto.txt).
34 * @timeout_us: Timeout in us, 0 means never timeout
35 *
36 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either
37 * case, the last read value at @addr is stored in @val. Must not
38 * be called from atomic context if sleep_us or timeout_us are used.
39 *
40 * When available, you'll probably want to use one of the specialized
41 * macros defined below rather than this macro directly.
42 */
43#define readx_poll_timeout(op, addr, val, cond, sleep_us, timeout_us) \
44({ \
45 u64 __timeout_us = (timeout_us); \
46 unsigned long __sleep_us = (sleep_us); \
47 ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \
48 might_sleep_if((__sleep_us) != 0); \
49 for (;;) { \
50 (val) = op(addr); \
51 if (cond) \
52 break; \
53 if (__timeout_us && \
54 ktime_compare(ktime_get(), __timeout) > 0) { \
55 (val) = op(addr); \
56 break; \
57 } \
58 if (__sleep_us) \
59 usleep_range((__sleep_us >> 2) + 1, __sleep_us); \
60 } \
61 (cond) ? 0 : -ETIMEDOUT; \
62})
63
64/**
65 * readx_poll_timeout_atomic - Periodically poll an address until a condition is met or a timeout occurs
66 * @op: accessor function (takes @addr as its only argument)
67 * @addr: Address to poll
68 * @val: Variable to read the value into
69 * @cond: Break condition (usually involving @val)
70 * @delay_us: Time to udelay between reads in us (0 tight-loops). Should
71 * be less than ~10us since udelay is used (see
72 * Documentation/timers/timers-howto.txt).
73 * @timeout_us: Timeout in us, 0 means never timeout
74 *
75 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either
76 * case, the last read value at @addr is stored in @val.
77 *
78 * When available, you'll probably want to use one of the specialized
79 * macros defined below rather than this macro directly.
80 */
81#define readx_poll_timeout_atomic(op, addr, val, cond, delay_us, timeout_us) \
82({ \
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 for (;;) { \
87 (val) = op(addr); \
88 if (cond) \
89 break; \
90 if (__timeout_us && \
91 ktime_compare(ktime_get(), __timeout) > 0) { \
92 (val) = op(addr); \
93 break; \
94 } \
95 if (__delay_us) \
96 udelay(__delay_us); \
97 } \
98 (cond) ? 0 : -ETIMEDOUT; \
99})
100
101
102#define readb_poll_timeout(addr, val, cond, delay_us, timeout_us) \
103 readx_poll_timeout(readb, addr, val, cond, delay_us, timeout_us)
104
105#define readb_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
106 readx_poll_timeout_atomic(readb, addr, val, cond, delay_us, timeout_us)
107
108#define readw_poll_timeout(addr, val, cond, delay_us, timeout_us) \
109 readx_poll_timeout(readw, addr, val, cond, delay_us, timeout_us)
110
111#define readw_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
112 readx_poll_timeout_atomic(readw, addr, val, cond, delay_us, timeout_us)
113
114#define readl_poll_timeout(addr, val, cond, delay_us, timeout_us) \
115 readx_poll_timeout(readl, addr, val, cond, delay_us, timeout_us)
116
117#define readl_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
118 readx_poll_timeout_atomic(readl, addr, val, cond, delay_us, timeout_us)
119
120#define readq_poll_timeout(addr, val, cond, delay_us, timeout_us) \
121 readx_poll_timeout(readq, addr, val, cond, delay_us, timeout_us)
122
123#define readq_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
124 readx_poll_timeout_atomic(readq, addr, val, cond, delay_us, timeout_us)
125
126#define readb_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
127 readx_poll_timeout(readb_relaxed, addr, val, cond, delay_us, timeout_us)
128
129#define readb_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
130 readx_poll_timeout_atomic(readb_relaxed, addr, val, cond, delay_us, timeout_us)
131
132#define readw_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
133 readx_poll_timeout(readw_relaxed, addr, val, cond, delay_us, timeout_us)
134
135#define readw_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
136 readx_poll_timeout_atomic(readw_relaxed, addr, val, cond, delay_us, timeout_us)
137
138#define readl_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
139 readx_poll_timeout(readl_relaxed, addr, val, cond, delay_us, timeout_us)
140
141#define readl_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
142 readx_poll_timeout_atomic(readl_relaxed, addr, val, cond, delay_us, timeout_us)
143
144#define readq_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
145 readx_poll_timeout(readq_relaxed, addr, val, cond, delay_us, timeout_us)
146
147#define readq_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
148 readx_poll_timeout_atomic(readq_relaxed, addr, val, cond, delay_us, timeout_us)
149
150#endif /* _LINUX_IOPOLL_H */
151