blob: 06ad43a122d69f5f58830ed387183e0f213d96df [file] [log] [blame]
* Wait for bit with timeout and ctrlc
* (C) Copyright 2015 Mateusz Kulikowski <>
* SPDX-License-Identifier: GPL-2.0+
#ifndef __WAIT_BIT_H
#define __WAIT_BIT_H
#include <common.h>
#include <console.h>
#include <watchdog.h>
#include <linux/errno.h>
#include <asm/io.h>
* wait_for_bit() waits for bit set/cleared in register
* Function polls register waiting for specific bit(s) change
* (either 0->1 or 1->0). It can fail under two conditions:
* - Timeout
* - User interaction (CTRL-C)
* Function succeeds only if all bits of masked register are set/cleared
* (depending on set option).
* @param prefix Prefix added to timeout messagge (message visible only
* with debug enabled)
* @param reg Register that will be read (using readl())
* @param mask Bit(s) of register that must be active
* @param set Selects wait condition (bit set or clear)
* @param timeout_ms Timeout (in miliseconds)
* @param breakable Enables CTRL-C interruption
* @return 0 on success, -ETIMEDOUT or -EINTR on failure
static inline int wait_for_bit(const char *prefix, const u32 *reg,
const u32 mask, const bool set,
const unsigned int timeout_ms,
const bool breakable)
u32 val;
unsigned long start = get_timer(0);
while (1) {
val = readl(reg);
if (!set)
val = ~val;
if ((val & mask) == mask)
return 0;
if (get_timer(start) > timeout_ms)
if (breakable && ctrlc()) {
return -EINTR;
debug("%s: Timeout (reg=%p mask=%08x wait_set=%i)\n", prefix, reg, mask,
return -ETIMEDOUT;