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 21 static inline uint64_t 22 agtimer_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 38 static inline u_int 39 agtimer_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 52 static inline u_int 53 agtimer_get_timecount_sun50i(struct timecounter *tc) 54 { 55 return agtimer_readcnt64_sun50i(); 56 } 57 58 static int 59 tc_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 73 int (*const _tc_get_timecount)(struct timekeep *, u_int *) = tc_get_timecount; 74