include/wait_bit.h

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