LXR uboot/include/wait

   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 <asm/errno.h>
  15#include <asm/io.h>
  16
  17/**
  18 * wait_for_bit()       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 prefix        Prefix added to timeout messagge (message visible only
  28 *                      with debug enabled)
  29 * @param reg           Register that will be read (using readl())
  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 miliseconds)
  33 * @param breakable     Enables CTRL-C interruption
  34 * @return              0 on success, -ETIMEDOUT or -EINTR on failure
  35 */
  36static inline int wait_for_bit(const char *prefix, const u32 *reg,
  37                               const u32 mask, const bool set,
  38                               const unsigned int timeout_ms,
  39                               const bool breakable)
  40{
  41        u32 val;
  42        unsigned long start = get_timer(0);
  43
  44        while (1) {
  45                val = readl(reg);
  46
  47                if (!set)
  48                        val = ~val;
  49
  50                if ((val & mask) == mask)
  51                        return 0;
  52
  53                if (get_timer(start) > timeout_ms)
  54                        break;
  55
  56                if (breakable && ctrlc()) {
  57                        puts("Abort\n");
  58                        return -EINTR;
  59                }
  60
  61                udelay(1);
  62        }
  63
  64        debug("%s: Timeout (reg=%p mask=%08x wait_set=%i)\n", prefix, reg, mask,
  65              set);
  66
  67        return -ETIMEDOUT;
  68}
  69
  70
  71#endif
  72