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 <watchdog.h>
  15#include <linux/errno.h>
  16#include <asm/io.h>
  17
  18/**
  19 * wait_for_bit()       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 prefix        Prefix added to timeout messagge (message visible only
  29 *                      with debug enabled)
  30 * @param reg           Register that will be read (using readl())
  31 * @param mask          Bit(s) of register that must be active
  32 * @param set           Selects wait condition (bit set or clear)
  33 * @param timeout_ms    Timeout (in miliseconds)
  34 * @param breakable     Enables CTRL-C interruption
  35 * @return              0 on success, -ETIMEDOUT or -EINTR on failure
  36 */
  37static inline int wait_for_bit(const char *prefix, const u32 *reg,
  38                               const u32 mask, const bool set,
  39                               const unsigned int timeout_ms,
  40                               const bool breakable)
  41{
  42        u32 val;
  43        unsigned long start = get_timer(0);
  44
  45        while (1) {
  46                val = readl(reg);
  47
  48                if (!set)
  49                        val = ~val;
  50
  51                if ((val & mask) == mask)
  52                        return 0;
  53
  54                if (get_timer(start) > timeout_ms)
  55                        break;
  56
  57                if (breakable && ctrlc()) {
  58                        puts("Abort\n");
  59                        return -EINTR;
  60                }
  61
  62                udelay(1);
  63                WATCHDOG_RESET();
  64        }
  65
  66        debug("%s: Timeout (reg=%p mask=%08x wait_set=%i)\n", prefix, reg, mask,
  67              set);
  68
  69        return -ETIMEDOUT;
  70}
  71
  72
  73#endif
  74