LXR linux/include/linux/iopoll.h

   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