wait_bit.h
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/*
* Wait for bit with timeout and ctrlc
*
* (C) Copyright 2015 Mateusz Kulikowski <mateusz.kulikowski@gmail.com>
*
* 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_x() 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 reg Register that will be read (using read_x())
* @param mask Bit(s) of register that must be active
* @param set Selects wait condition (bit set or clear)
* @param timeout_ms Timeout (in milliseconds)
* @param breakable Enables CTRL-C interruption
* @return 0 on success, -ETIMEDOUT or -EINTR on failure
*/
#define BUILD_WAIT_FOR_BIT(sfx, type, read) \
\
static inline int wait_for_bit_##sfx(const void *reg, \
const type mask, \
const bool set, \
const unsigned int timeout_ms, \
const bool breakable) \
{ \
type val; \
unsigned long start = get_timer(0); \
\
while (1) { \
val = read(reg); \
\
if (!set) \
val = ~val; \
\
if ((val & mask) == mask) \
return 0; \
\
if (get_timer(start) > timeout_ms) \
break; \
\
if (breakable && ctrlc()) { \
puts("Abort\n"); \
return -EINTR; \
} \
\
udelay(1); \
WATCHDOG_RESET(); \
} \
\
debug("%s: Timeout (reg=%p mask=%x wait_set=%i)\n", __func__, \
reg, mask, set); \
\
return -ETIMEDOUT; \
}
BUILD_WAIT_FOR_BIT(8, u8, readb)
BUILD_WAIT_FOR_BIT(le16, u16, readw)
#ifdef readw_be
BUILD_WAIT_FOR_BIT(be16, u16, readw_be)
#endif
BUILD_WAIT_FOR_BIT(le32, u32, readl)
#ifdef readl_be
BUILD_WAIT_FOR_BIT(be32, u32, readl_be)
#endif
#endif