include/wait_bit.h

   1 /* SPDX-License-Identifier: GPL-2.0+ */
   2 /*
   3  * Wait for bit with timeout and ctrlc
   4  *
   5  * (C) Copyright 2015 Mateusz Kulikowski <mateusz.kulikowski@gmail.com>
   6  */
   7
   8 #ifndef __WAIT_BIT_H
   9 #define __WAIT_BIT_H
  10
  11 #include <console.h>
  12 #include <log.h>
  13 #include <time.h>
  14 #include <watchdog.h>
  15 #include <linux/delay.h>
  16 #include <linux/errno.h>
  17 #include <asm/io.h>
  18
  19 /**
  20  * wait_for_bit_x()     waits for bit set/cleared in register
  21  *
  22  * Function polls register waiting for specific bit(s) change
  23  * (either 0->1 or 1->0). It can fail under two conditions:
  24  * - Timeout
  25  * - User interaction (CTRL-C)
  26  * Function succeeds only if all bits of masked register are set/cleared
  27  * (depending on set option).
  28  *
  29  * @param reg           Register that will be read (using read_x())
  30  * @param mask          Bit(s) of register that must be active
  31  * @param set           Selects wait condition (bit set or clear)
  32  * @param timeout_ms    Timeout (in milliseconds)
  33  * @param breakable     Enables CTRL-C interruption
  34  * Return:              0 on success, -ETIMEDOUT or -EINTR on failure
  35  */
  36
  37 #define BUILD_WAIT_FOR_BIT(sfx, type, read)                             \
  38                                                                         \
  39 static inline int wait_for_bit_##sfx(const void *reg,                   \
  40                                      const type mask,                   \
  41                                      const bool set,                    \
  42                                      const unsigned int timeout_ms,     \
  43                                      const bool breakable)              \
  44 {                                                                       \
  45         type val;                                                       \
  46         unsigned long start = get_timer(0);                             \
  47                                                                         \
  48         while (1) {                                                     \
  49                 val = read(reg);                                        \
  50                                                                         \
  51                 if (!set)                                               \
  52                         val = ~val;                                     \
  53                                                                         \
  54                 if ((val & mask) == mask)                               \
  55                         return 0;                                       \
  56                                                                         \
  57                 if (get_timer(start) > timeout_ms)                      \
  58                         break;                                          \
  59                                                                         \
  60                 if (breakable && ctrlc()) {                             \
  61                         puts("Abort\n");                                \
  62                         return -EINTR;                                  \
  63                 }                                                       \
  64                                                                         \
  65                 udelay(1);                                              \
  66                 schedule();                                     \
  67         }                                                               \
  68                                                                         \
  69         debug("%s: Timeout (reg=%p mask=%x wait_set=%i)\n", __func__,   \
  70               reg, mask, set);                                          \
  71                                                                         \
  72         return -ETIMEDOUT;                                              \
  73 }
  74
  75 BUILD_WAIT_FOR_BIT(8, u8, readb)
  76 BUILD_WAIT_FOR_BIT(le16, u16, readw)
  77 BUILD_WAIT_FOR_BIT(16, u16, readw)
  78 #ifdef readw_be
  79 BUILD_WAIT_FOR_BIT(be16, u16, readw_be)
  80 #endif
  81 BUILD_WAIT_FOR_BIT(le32, u32, readl)
  82 BUILD_WAIT_FOR_BIT(32, u32, readl)
  83 #ifdef readl_be
  84 BUILD_WAIT_FOR_BIT(be32, u32, readl_be)
  85 #endif
  86
  87 #endif