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 * readx_poll_timeout - Periodically poll an address until a condition is met or a timeout occurs
  18 * @op: accessor function (takes @addr as its only argument)
  19 * @addr: Address to poll
  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.txt).
  25 * @timeout_us: Timeout in us, 0 means never timeout
  26 *
  27 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either
  28 * case, the last read value at @addr is stored in @val. Must not
  29 * be called from atomic context if sleep_us or timeout_us are used.
  30 *
  31 * When available, you'll probably want to use one of the specialized
  32 * macros defined below rather than this macro directly.
  33 */
  34#define readx_poll_timeout(op, addr, val, cond, sleep_us, timeout_us)   \
  35({ \
  36        u64 __timeout_us = (timeout_us); \
  37        unsigned long __sleep_us = (sleep_us); \
  38        ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \
  39        might_sleep_if((__sleep_us) != 0); \
  40        for (;;) { \
  41                (val) = op(addr); \
  42                if (cond) \
  43                        break; \
  44                if (__timeout_us && \
  45                    ktime_compare(ktime_get(), __timeout) > 0) { \
  46                        (val) = op(addr); \
  47                        break; \
  48                } \
  49                if (__sleep_us) \
  50                        usleep_range((__sleep_us >> 2) + 1, __sleep_us); \
  51        } \
  52        (cond) ? 0 : -ETIMEDOUT; \
  53})
  54
  55/**
  56 * readx_poll_timeout_atomic - Periodically poll an address until a condition is met or a timeout occurs
  57 * @op: accessor function (takes @addr as its only argument)
  58 * @addr: Address to poll
  59 * @val: Variable to read the value into
  60 * @cond: Break condition (usually involving @val)
  61 * @delay_us: Time to udelay between reads in us (0 tight-loops).  Should
  62 *            be less than ~10us since udelay is used (see
  63 *            Documentation/timers/timers-howto.txt).
  64 * @timeout_us: Timeout in us, 0 means never timeout
  65 *
  66 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either
  67 * case, the last read value at @addr is stored in @val.
  68 *
  69 * When available, you'll probably want to use one of the specialized
  70 * macros defined below rather than this macro directly.
  71 */
  72#define readx_poll_timeout_atomic(op, addr, val, cond, delay_us, timeout_us) \
  73({ \
  74        u64 __timeout_us = (timeout_us); \
  75        unsigned long __delay_us = (delay_us); \
  76        ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \
  77        for (;;) { \
  78                (val) = op(addr); \
  79                if (cond) \
  80                        break; \
  81                if (__timeout_us && \
  82                    ktime_compare(ktime_get(), __timeout) > 0) { \
  83                        (val) = op(addr); \
  84                        break; \
  85                } \
  86                if (__delay_us) \
  87                        udelay(__delay_us);     \
  88        } \
  89        (cond) ? 0 : -ETIMEDOUT; \
  90})
  91
  92
  93#define readb_poll_timeout(addr, val, cond, delay_us, timeout_us) \
  94        readx_poll_timeout(readb, addr, val, cond, delay_us, timeout_us)
  95
  96#define readb_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
  97        readx_poll_timeout_atomic(readb, addr, val, cond, delay_us, timeout_us)
  98
  99#define readw_poll_timeout(addr, val, cond, delay_us, timeout_us) \
 100        readx_poll_timeout(readw, addr, val, cond, delay_us, timeout_us)
 101
 102#define readw_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
 103        readx_poll_timeout_atomic(readw, addr, val, cond, delay_us, timeout_us)
 104
 105#define readl_poll_timeout(addr, val, cond, delay_us, timeout_us) \
 106        readx_poll_timeout(readl, addr, val, cond, delay_us, timeout_us)
 107
 108#define readl_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
 109        readx_poll_timeout_atomic(readl, addr, val, cond, delay_us, timeout_us)
 110
 111#define readq_poll_timeout(addr, val, cond, delay_us, timeout_us) \
 112        readx_poll_timeout(readq, addr, val, cond, delay_us, timeout_us)
 113
 114#define readq_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
 115        readx_poll_timeout_atomic(readq, addr, val, cond, delay_us, timeout_us)
 116
 117#define readb_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
 118        readx_poll_timeout(readb_relaxed, addr, val, cond, delay_us, timeout_us)
 119
 120#define readb_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
 121        readx_poll_timeout_atomic(readb_relaxed, addr, val, cond, delay_us, timeout_us)
 122
 123#define readw_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
 124        readx_poll_timeout(readw_relaxed, addr, val, cond, delay_us, timeout_us)
 125
 126#define readw_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
 127        readx_poll_timeout_atomic(readw_relaxed, addr, val, cond, delay_us, timeout_us)
 128
 129#define readl_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
 130        readx_poll_timeout(readl_relaxed, addr, val, cond, delay_us, timeout_us)
 131
 132#define readl_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
 133        readx_poll_timeout_atomic(readl_relaxed, addr, val, cond, delay_us, timeout_us)
 134
 135#define readq_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
 136        readx_poll_timeout(readq_relaxed, addr, val, cond, delay_us, timeout_us)
 137
 138#define readq_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
 139        readx_poll_timeout_atomic(readq_relaxed, addr, val, cond, delay_us, timeout_us)
 140
 141#endif /* _LINUX_IOPOLL_H */
 142