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