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Mateusz Kulikowski9afdf402016-01-23 11:54:29 +01001/*
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