1/*	$OpenBSD: usertc.c,v 1.3 2023/02/05 13:37:51 kettenis Exp $	*/
2/*
3 * Copyright (c) 2020 Mark Kettenis <kettenis@openbsd.org>
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18#include <sys/types.h>
19#include <sys/timetc.h>
20
21static inline uint64_t
22agtimer_readcnt64_sun50i(void)
23{
24	uint64_t val;
25	int retry;
26
27	__asm volatile("isb" ::: "memory");
28	for (retry = 0; retry < 150; retry++) {
29		__asm volatile("mrs %x0, CNTVCT_EL0" : "=r" (val));
30
31		if (((val + 1) & 0x1ff) > 1)
32			break;
33	}
34
35	return val;
36}
37
38static inline u_int
39agtimer_get_timecount_default(struct timecounter *tc)
40{
41	uint64_t val;
42
43	/*
44	 * No need to work around Cortex-A73 errata 858921 since we
45	 * only look at the low 32 bits here.
46	 */
47	__asm volatile("isb" ::: "memory");
48	__asm volatile("mrs %x0, CNTVCT_EL0" : "=r" (val));
49	return (val & 0xffffffff);
50}
51
52static inline u_int
53agtimer_get_timecount_sun50i(struct timecounter *tc)
54{
55	return agtimer_readcnt64_sun50i();
56}
57
58static int
59tc_get_timecount(struct timekeep *tk, u_int *tc)
60{
61	switch (tk->tk_user) {
62	case TC_AGTIMER:
63		*tc = agtimer_get_timecount_default(NULL);
64		return 0;
65	case TC_AGTIMER_SUN50I:
66		*tc = agtimer_get_timecount_sun50i(NULL);
67		return 0;
68	}
69
70	return -1;
71}
72
73int (*const _tc_get_timecount)(struct timekeep *, u_int *) = tc_get_timecount;
74