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/hrtimer.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 */