root/include/linux/iopoll.h

INCLUDED FROM

   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.rst).
  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.rst).
  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 */