1/* SPDX-License-Identifier: GPL-2.0+ */
2/*
3 * Wait for bit with timeout and ctrlc
4 *
5 * (C) Copyright 2015 Mateusz Kulikowski <mateusz.kulikowski@gmail.com>
6 */
7
8#ifndef __WAIT_BIT_H
9#define __WAIT_BIT_H
10
11#include <console.h>
12#include <log.h>
13#include <time.h>
14#include <watchdog.h>
15#include <linux/delay.h>
16#include <linux/errno.h>
17#include <asm/io.h>
18
19/**
20 * wait_for_bit_x()	waits for bit set/cleared in register
21 *
22 * Function polls register waiting for specific bit(s) change
23 * (either 0->1 or 1->0). It can fail under two conditions:
24 * - Timeout
25 * - User interaction (CTRL-C)
26 * Function succeeds only if all bits of masked register are set/cleared
27 * (depending on set option).
28 *
29 * @param reg		Register that will be read (using read_x())
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 milliseconds)
33 * @param breakable	Enables CTRL-C interruption
34 * Return:		0 on success, -ETIMEDOUT or -EINTR on failure
35 */
36
37#define BUILD_WAIT_FOR_BIT(sfx, type, read)				\
38									\
39static inline int wait_for_bit_##sfx(const void *reg,			\
40				     const type mask,			\
41				     const bool set,			\
42				     const unsigned int timeout_ms,	\
43				     const bool breakable)		\
44{									\
45	type val;							\
46	unsigned long start = get_timer(0);				\
47									\
48	while (1) {							\
49		val = read(reg);					\
50									\
51		if (!set)						\
52			val = ~val;					\
53									\
54		if ((val & mask) == mask)				\
55			return 0;					\
56									\
57		if (get_timer(start) > timeout_ms)			\
58			break;						\
59									\
60		if (breakable && ctrlc()) {				\
61			puts("Abort\n");				\
62			return -EINTR;					\
63		}							\
64									\
65		udelay(1);						\
66		schedule();					\
67	}								\
68									\
69	debug("%s: Timeout (reg=%p mask=%x wait_set=%i)\n", __func__,	\
70	      reg, mask, set);						\
71									\
72	return -ETIMEDOUT;						\
73}
74
75BUILD_WAIT_FOR_BIT(8, u8, readb)
76BUILD_WAIT_FOR_BIT(le16, u16, readw)
77BUILD_WAIT_FOR_BIT(16, u16, readw)
78#ifdef readw_be
79BUILD_WAIT_FOR_BIT(be16, u16, readw_be)
80#endif
81BUILD_WAIT_FOR_BIT(le32, u32, readl)
82BUILD_WAIT_FOR_BIT(32, u32, readl)
83#ifdef readl_be
84BUILD_WAIT_FOR_BIT(be32, u32, readl_be)
85#endif
86
87#endif
88