LXR linux/include/linux/iopoll.h

   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