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        ktime_t timeout = ktime_add_us(ktime_get(), timeout_us); \
  46        might_sleep_if(sleep_us); \
  47        for (;;) { \
  48                (val) = op(addr); \
  49                if (cond) \
  50                        break; \
  51                if (timeout_us && ktime_compare(ktime_get(), timeout) > 0) { \
  52                        (val) = op(addr); \
  53                        break; \
  54                } \
  55                if (sleep_us) \
  56                        usleep_range((sleep_us >> 2) + 1, sleep_us); \
  57        } \
  58        (cond) ? 0 : -ETIMEDOUT; \
  59})
  60
  61/**
  62 * readx_poll_timeout_atomic - Periodically poll an address until a condition is met or a timeout occurs
  63 * @op: accessor function (takes @addr as its only argument)
  64 * @addr: Address to poll
  65 * @val: Variable to read the value into
  66 * @cond: Break condition (usually involving @val)
  67 * @delay_us: Time to udelay between reads in us (0 tight-loops).  Should
  68 *            be less than ~10us since udelay is used (see
  69 *            Documentation/timers/timers-howto.txt).
  70 * @timeout_us: Timeout in us, 0 means never timeout
  71 *
  72 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either
  73 * case, the last read value at @addr is stored in @val.
  74 *
  75 * When available, you'll probably want to use one of the specialized
  76 * macros defined below rather than this macro directly.
  77 */
  78#define readx_poll_timeout_atomic(op, addr, val, cond, delay_us, timeout_us) \
  79({ \
  80        ktime_t timeout = ktime_add_us(ktime_get(), timeout_us); \
  81        for (;;) { \
  82                (val) = op(addr); \
  83                if (cond) \
  84                        break; \
  85                if (timeout_us && ktime_compare(ktime_get(), timeout) > 0) { \
  86                        (val) = op(addr); \
  87                        break; \
  88                } \
  89                if (delay_us) \
  90                        udelay(delay_us);       \
  91        } \
  92        (cond) ? 0 : -ETIMEDOUT; \
  93})
  94
  95
  96#define readb_poll_timeout(addr, val, cond, delay_us, timeout_us) \
  97        readx_poll_timeout(readb, addr, val, cond, delay_us, timeout_us)
  98
  99#define readb_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
 100        readx_poll_timeout_atomic(readb, addr, val, cond, delay_us, timeout_us)
 101
 102#define readw_poll_timeout(addr, val, cond, delay_us, timeout_us) \
 103        readx_poll_timeout(readw, addr, val, cond, delay_us, timeout_us)
 104
 105#define readw_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
 106        readx_poll_timeout_atomic(readw, addr, val, cond, delay_us, timeout_us)
 107
 108#define readl_poll_timeout(addr, val, cond, delay_us, timeout_us) \
 109        readx_poll_timeout(readl, addr, val, cond, delay_us, timeout_us)
 110
 111#define readl_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
 112        readx_poll_timeout_atomic(readl, addr, val, cond, delay_us, timeout_us)
 113
 114#define readq_poll_timeout(addr, val, cond, delay_us, timeout_us) \
 115        readx_poll_timeout(readq, addr, val, cond, delay_us, timeout_us)
 116
 117#define readq_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
 118        readx_poll_timeout_atomic(readq, addr, val, cond, delay_us, timeout_us)
 119
 120#define readb_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
 121        readx_poll_timeout(readb_relaxed, addr, val, cond, delay_us, timeout_us)
 122
 123#define readb_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
 124        readx_poll_timeout_atomic(readb_relaxed, addr, val, cond, delay_us, timeout_us)
 125
 126#define readw_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
 127        readx_poll_timeout(readw_relaxed, addr, val, cond, delay_us, timeout_us)
 128
 129#define readw_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
 130        readx_poll_timeout_atomic(readw_relaxed, addr, val, cond, delay_us, timeout_us)
 131
 132#define readl_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
 133        readx_poll_timeout(readl_relaxed, addr, val, cond, delay_us, timeout_us)
 134
 135#define readl_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
 136        readx_poll_timeout_atomic(readl_relaxed, addr, val, cond, delay_us, timeout_us)
 137
 138#define readq_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
 139        readx_poll_timeout(readq_relaxed, addr, val, cond, delay_us, timeout_us)
 140
 141#define readq_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
 142        readx_poll_timeout_atomic(readq_relaxed, addr, val, cond, delay_us, timeout_us)
 143
 144#endif /* _LINUX_IOPOLL_H */
 145