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  * read_poll_timeout - Periodically poll an address until a condition is
  18  *                      met or a timeout occurs
  19  * @op: accessor function (takes @args as its arguments)
  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 tight-loops). Please
  23  *            read usleep_range() function description for details and
  24  *            limitations.
  25  * @timeout_us: Timeout in us, 0 means never timeout
  26  * @sleep_before_read: if it is true, sleep @sleep_us before read.
  27  * @args: arguments for @op poll
  28  *
  29  * When available, you'll probably want to use one of the specialized
  30  * macros defined below rather than this macro directly.
  31  *
  32  * Returns: 0 on success and -ETIMEDOUT upon a timeout. In either
  33  * case, the last read value at @args is stored in @val. Must not
  34  * be called from atomic context if sleep_us or timeout_us are used.
  35  */
  36 #define read_poll_timeout(op, val, cond, sleep_us, timeout_us, \
  37                                 sleep_before_read, args...) \
  38 ({ \
  39         u64 __timeout_us = (timeout_us); \
  40         unsigned long __sleep_us = (sleep_us); \
  41         ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \
  42         might_sleep_if((__sleep_us) != 0); \
  43         if (sleep_before_read && __sleep_us) \
  44                 usleep_range((__sleep_us >> 2) + 1, __sleep_us); \
  45         for (;;) { \
  46                 (val) = op(args); \
  47                 if (cond) \
  48                         break; \
  49                 if (__timeout_us && \
  50                     ktime_compare(ktime_get(), __timeout) > 0) { \
  51                         (val) = op(args); \
  52                         break; \
  53                 } \
  54                 if (__sleep_us) \
  55                         usleep_range((__sleep_us >> 2) + 1, __sleep_us); \
  56                 cpu_relax(); \
  57         } \
  58         (cond) ? 0 : -ETIMEDOUT; \
  59 })
  60
  61 /**
  62  * read_poll_timeout_atomic - Periodically poll an address until a condition is
  63  *                              met or a timeout occurs
  64  * @op: accessor function (takes @args as its arguments)
  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). Please
  68  *            read udelay() function description for details and
  69  *            limitations.
  70  * @timeout_us: Timeout in us, 0 means never timeout
  71  * @delay_before_read: if it is true, delay @delay_us before read.
  72  * @args: arguments for @op poll
  73  *
  74  * This macro does not rely on timekeeping.  Hence it is safe to call even when
  75  * timekeeping is suspended, at the expense of an underestimation of wall clock
  76  * time, which is rather minimal with a non-zero delay_us.
  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  * Returns: 0 on success and -ETIMEDOUT upon a timeout. In either
  82  * case, the last read value at @args is stored in @val.
  83  */
  84 #define read_poll_timeout_atomic(op, val, cond, delay_us, timeout_us, \
  85                                         delay_before_read, args...) \
  86 ({ \
  87         u64 __timeout_us = (timeout_us); \
  88         s64 __left_ns = __timeout_us * NSEC_PER_USEC; \
  89         unsigned long __delay_us = (delay_us); \
  90         u64 __delay_ns = __delay_us * NSEC_PER_USEC; \
  91         if (delay_before_read && __delay_us) { \
  92                 udelay(__delay_us); \
  93                 if (__timeout_us) \
  94                         __left_ns -= __delay_ns; \
  95         } \
  96         for (;;) { \
  97                 (val) = op(args); \
  98                 if (cond) \
  99                         break; \
 100                 if (__timeout_us && __left_ns < 0) { \
 101                         (val) = op(args); \
 102                         break; \
 103                 } \
 104                 if (__delay_us) { \
 105                         udelay(__delay_us); \
 106                         if (__timeout_us) \
 107                                 __left_ns -= __delay_ns; \
 108                 } \
 109                 cpu_relax(); \
 110                 if (__timeout_us) \
 111                         __left_ns--; \
 112         } \
 113         (cond) ? 0 : -ETIMEDOUT; \
 114 })
 115
 116 /**
 117  * readx_poll_timeout - Periodically poll an address until a condition is met or a timeout occurs
 118  * @op: accessor function (takes @addr as its only argument)
 119  * @addr: Address to poll
 120  * @val: Variable to read the value into
 121  * @cond: Break condition (usually involving @val)
 122  * @sleep_us: Maximum time to sleep between reads in us (0 tight-loops). Please
 123  *            read usleep_range() function description for details and
 124  *            limitations.
 125  * @timeout_us: Timeout in us, 0 means never timeout
 126  *
 127  * When available, you'll probably want to use one of the specialized
 128  * macros defined below rather than this macro directly.
 129  *
 130  * Returns: 0 on success and -ETIMEDOUT upon a timeout. In either
 131  * case, the last read value at @addr is stored in @val. Must not
 132  * be called from atomic context if sleep_us or timeout_us are used.
 133  */
 134 #define readx_poll_timeout(op, addr, val, cond, sleep_us, timeout_us)   \
 135         read_poll_timeout(op, val, cond, sleep_us, timeout_us, false, addr)
 136
 137 /**
 138  * readx_poll_timeout_atomic - Periodically poll an address until a condition is met or a timeout occurs
 139  * @op: accessor function (takes @addr as its only argument)
 140  * @addr: Address to poll
 141  * @val: Variable to read the value into
 142  * @cond: Break condition (usually involving @val)
 143  * @delay_us: Time to udelay between reads in us (0 tight-loops). Please
 144  *            read udelay() function description for details and
 145  *            limitations.
 146  * @timeout_us: Timeout in us, 0 means never timeout
 147  *
 148  * When available, you'll probably want to use one of the specialized
 149  * macros defined below rather than this macro directly.
 150  *
 151  * Returns: 0 on success and -ETIMEDOUT upon a timeout. In either
 152  * case, the last read value at @addr is stored in @val.
 153  */
 154 #define readx_poll_timeout_atomic(op, addr, val, cond, delay_us, timeout_us) \
 155         read_poll_timeout_atomic(op, val, cond, delay_us, timeout_us, false, addr)
 156
 157 #define readb_poll_timeout(addr, val, cond, delay_us, timeout_us) \
 158         readx_poll_timeout(readb, addr, val, cond, delay_us, timeout_us)
 159
 160 #define readb_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
 161         readx_poll_timeout_atomic(readb, addr, val, cond, delay_us, timeout_us)
 162
 163 #define readw_poll_timeout(addr, val, cond, delay_us, timeout_us) \
 164         readx_poll_timeout(readw, addr, val, cond, delay_us, timeout_us)
 165
 166 #define readw_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
 167         readx_poll_timeout_atomic(readw, addr, val, cond, delay_us, timeout_us)
 168
 169 #define readl_poll_timeout(addr, val, cond, delay_us, timeout_us) \
 170         readx_poll_timeout(readl, addr, val, cond, delay_us, timeout_us)
 171
 172 #define readl_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
 173         readx_poll_timeout_atomic(readl, addr, val, cond, delay_us, timeout_us)
 174
 175 #define readq_poll_timeout(addr, val, cond, delay_us, timeout_us) \
 176         readx_poll_timeout(readq, addr, val, cond, delay_us, timeout_us)
 177
 178 #define readq_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
 179         readx_poll_timeout_atomic(readq, addr, val, cond, delay_us, timeout_us)
 180
 181 #define readb_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
 182         readx_poll_timeout(readb_relaxed, addr, val, cond, delay_us, timeout_us)
 183
 184 #define readb_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
 185         readx_poll_timeout_atomic(readb_relaxed, addr, val, cond, delay_us, timeout_us)
 186
 187 #define readw_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
 188         readx_poll_timeout(readw_relaxed, addr, val, cond, delay_us, timeout_us)
 189
 190 #define readw_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
 191         readx_poll_timeout_atomic(readw_relaxed, addr, val, cond, delay_us, timeout_us)
 192
 193 #define readl_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
 194         readx_poll_timeout(readl_relaxed, addr, val, cond, delay_us, timeout_us)
 195
 196 #define readl_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
 197         readx_poll_timeout_atomic(readl_relaxed, addr, val, cond, delay_us, timeout_us)
 198
 199 #define readq_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
 200         readx_poll_timeout(readq_relaxed, addr, val, cond, delay_us, timeout_us)
 201
 202 #define readq_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
 203         readx_poll_timeout_atomic(readq_relaxed, addr, val, cond, delay_us, timeout_us)
 204
 205 #endif /* _LINUX_IOPOLL_H */