include/linux/iopoll.h

   1 /*
   2  * Copyright (c) 2012-2014 The Linux Foundation. All rights reserved.
   3  *
   4  * SPDX-License-Identifier:     GPL-2.0
   5  */
   6
   7 #ifndef _LINUX_IOPOLL_H
   8 #define _LINUX_IOPOLL_H
   9
  10 #include <linux/errno.h>
  11 #include <linux/io.h>
  12 #include <time.h>
  13
  14 /**
  15  * readx_poll_timeout - Periodically poll an address until a condition is met or a timeout occurs
  16  * @op: accessor function (takes @addr as its only argument)
  17  * @addr: Address to poll
  18  * @val: Variable to read the value into
  19  * @cond: Break condition (usually involving @val)
  20  * @timeout_us: Timeout in us, 0 means never timeout
  21  *
  22  * Returns 0 on success and -ETIMEDOUT upon a timeout. In either
  23  * case, the last read value at @addr is stored in @val.
  24  *
  25  * When available, you'll probably want to use one of the specialized
  26  * macros defined below rather than this macro directly.
  27  */
  28 #define readx_poll_timeout(op, addr, val, cond, timeout_us)     \
  29 ({ \
  30         unsigned long timeout = timer_get_us() + timeout_us; \
  31         for (;;) { \
  32                 (val) = op(addr); \
  33                 if (cond) \
  34                         break; \
  35                 if (timeout_us && time_after(timer_get_us(), timeout)) { \
  36                         (val) = op(addr); \
  37                         break; \
  38                 } \
  39         } \
  40         (cond) ? 0 : -ETIMEDOUT; \
  41 })
  42
  43
  44 #define readb_poll_timeout(addr, val, cond, timeout_us) \
  45         readx_poll_timeout(readb, addr, val, cond, timeout_us)
  46
  47 #define readw_poll_timeout(addr, val, cond, timeout_us) \
  48         readx_poll_timeout(readw, addr, val, cond, timeout_us)
  49
  50 #define readl_poll_timeout(addr, val, cond, timeout_us) \
  51         readx_poll_timeout(readl, addr, val, cond, timeout_us)
  52
  53 #define readq_poll_timeout(addr, val, cond, timeout_us) \
  54         readx_poll_timeout(readq, addr, val, cond, timeout_us)
  55
  56 #define readb_relaxed_poll_timeout(addr, val, cond, timeout_us) \
  57         readx_poll_timeout(readb_relaxed, addr, val, cond, timeout_us)
  58
  59 #define readw_relaxed_poll_timeout(addr, val, cond, timeout_us) \
  60         readx_poll_timeout(readw_relaxed, addr, val, cond, timeout_us)
  61
  62 #define readl_relaxed_poll_timeout(addr, val, cond, timeout_us) \
  63         readx_poll_timeout(readl_relaxed, addr, val, cond, timeout_us)
  64
  65 #define readq_relaxed_poll_timeout(addr, val, cond, timeout_us) \
  66         readx_poll_timeout(readq_relaxed, addr, val, cond, timeout_us)
  67
  68 #endif /* _LINUX_IOPOLL_H */