1 /* SPDX-License-Identifier: MIT */
2 /* Copyright © 2025 Intel Corporation */
3
4 #ifndef __INTEL_DISPLAY_JIFFIES_H__
5 #define __INTEL_DISPLAY_JIFFIES_H__
6
7 #include <linux/jiffies.h>
8
msecs_to_jiffies_timeout(const unsigned int m)9 static inline unsigned long msecs_to_jiffies_timeout(const unsigned int m)
10 {
11 unsigned long j = msecs_to_jiffies(m);
12
13 return min_t(unsigned long, MAX_JIFFY_OFFSET, j + 1);
14 }
15
16 /*
17 * If you need to wait X milliseconds between events A and B, but event B
18 * doesn't happen exactly after event A, you record the timestamp (jiffies) of
19 * when event A happened, then just before event B you call this function and
20 * pass the timestamp as the first argument, and X as the second argument.
21 */
22 static inline void
wait_remaining_ms_from_jiffies(unsigned long timestamp_jiffies,int to_wait_ms)23 wait_remaining_ms_from_jiffies(unsigned long timestamp_jiffies, int to_wait_ms)
24 {
25 unsigned long target_jiffies, tmp_jiffies, remaining_jiffies;
26
27 /*
28 * Don't re-read the value of "jiffies" every time since it may change
29 * behind our back and break the math.
30 */
31 tmp_jiffies = jiffies;
32 target_jiffies = timestamp_jiffies +
33 msecs_to_jiffies_timeout(to_wait_ms);
34
35 if (time_after(target_jiffies, tmp_jiffies)) {
36 remaining_jiffies = target_jiffies - tmp_jiffies;
37 while (remaining_jiffies)
38 remaining_jiffies =
39 schedule_timeout_uninterruptible(remaining_jiffies);
40 }
41 }
42
43 #endif /* __INTEL_DISPLAY_JIFFIES_H__ */
44