11802d0beSThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only
23bd69ad1SAndreas Eversberg /*
33bd69ad1SAndreas Eversberg * Copyright 2008 by Andreas Eversberg <andreas@eversberg.eu>
43bd69ad1SAndreas Eversberg *
53bd69ad1SAndreas Eversberg * Quick API description:
63bd69ad1SAndreas Eversberg *
73bd69ad1SAndreas Eversberg * A clock source registers using mISDN_register_clock:
83bd69ad1SAndreas Eversberg * name = text string to name clock source
93bd69ad1SAndreas Eversberg * priority = value to priorize clock sources (0 = default)
103bd69ad1SAndreas Eversberg * ctl = callback function to enable/disable clock source
113bd69ad1SAndreas Eversberg * priv = private pointer of clock source
123bd69ad1SAndreas Eversberg * return = pointer to clock source structure;
133bd69ad1SAndreas Eversberg *
143bd69ad1SAndreas Eversberg * Note: Callback 'ctl' can be called before mISDN_register_clock returns!
153bd69ad1SAndreas Eversberg * Also it can be called during mISDN_unregister_clock.
163bd69ad1SAndreas Eversberg *
173bd69ad1SAndreas Eversberg * A clock source calls mISDN_clock_update with given samples elapsed, if
183bd69ad1SAndreas Eversberg * enabled. If function call is delayed, tv must be set with the timestamp
193bd69ad1SAndreas Eversberg * of the actual event.
203bd69ad1SAndreas Eversberg *
213bd69ad1SAndreas Eversberg * A clock source unregisters using mISDN_unregister_clock.
223bd69ad1SAndreas Eversberg *
233bd69ad1SAndreas Eversberg * To get current clock, call mISDN_clock_get. The signed short value
243bd69ad1SAndreas Eversberg * counts the number of samples since. Time since last clock event is added.
253bd69ad1SAndreas Eversberg */
263bd69ad1SAndreas Eversberg
275a0e3ad6STejun Heo #include <linux/slab.h>
283bd69ad1SAndreas Eversberg #include <linux/types.h>
293bd69ad1SAndreas Eversberg #include <linux/stddef.h>
303bd69ad1SAndreas Eversberg #include <linux/spinlock.h>
31ebf918cfSTina Ruchandani #include <linux/ktime.h>
323bd69ad1SAndreas Eversberg #include <linux/mISDNif.h>
335d76fc21SPaul Gortmaker #include <linux/export.h>
343bd69ad1SAndreas Eversberg #include "core.h"
353bd69ad1SAndreas Eversberg
363bd69ad1SAndreas Eversberg static u_int *debug;
373bd69ad1SAndreas Eversberg static LIST_HEAD(iclock_list);
38f8532fdeSHannes Eder static DEFINE_RWLOCK(iclock_lock);
39f8532fdeSHannes Eder static u16 iclock_count; /* counter of last clock */
40ebf918cfSTina Ruchandani static ktime_t iclock_timestamp; /* time stamp of last clock */
41ebf918cfSTina Ruchandani static int iclock_timestamp_valid; /* already received one timestamp */
42f8532fdeSHannes Eder static struct mISDNclock *iclock_current;
433bd69ad1SAndreas Eversberg
443bd69ad1SAndreas Eversberg void
mISDN_init_clock(u_int * dp)453bd69ad1SAndreas Eversberg mISDN_init_clock(u_int *dp)
463bd69ad1SAndreas Eversberg {
473bd69ad1SAndreas Eversberg debug = dp;
48ebf918cfSTina Ruchandani iclock_timestamp = ktime_get();
493bd69ad1SAndreas Eversberg }
503bd69ad1SAndreas Eversberg
513bd69ad1SAndreas Eversberg static void
select_iclock(void)523bd69ad1SAndreas Eversberg select_iclock(void)
533bd69ad1SAndreas Eversberg {
543bd69ad1SAndreas Eversberg struct mISDNclock *iclock, *bestclock = NULL, *lastclock = NULL;
553bd69ad1SAndreas Eversberg int pri = -128;
563bd69ad1SAndreas Eversberg
573bd69ad1SAndreas Eversberg list_for_each_entry(iclock, &iclock_list, list) {
583bd69ad1SAndreas Eversberg if (iclock->pri > pri) {
593bd69ad1SAndreas Eversberg pri = iclock->pri;
603bd69ad1SAndreas Eversberg bestclock = iclock;
613bd69ad1SAndreas Eversberg }
623bd69ad1SAndreas Eversberg if (iclock_current == iclock)
633bd69ad1SAndreas Eversberg lastclock = iclock;
643bd69ad1SAndreas Eversberg }
653bd69ad1SAndreas Eversberg if (lastclock && bestclock != lastclock) {
663bd69ad1SAndreas Eversberg /* last used clock source still exists but changes, disable */
673bd69ad1SAndreas Eversberg if (*debug & DEBUG_CLOCK)
683bd69ad1SAndreas Eversberg printk(KERN_DEBUG "Old clock source '%s' disable.\n",
693bd69ad1SAndreas Eversberg lastclock->name);
703bd69ad1SAndreas Eversberg lastclock->ctl(lastclock->priv, 0);
713bd69ad1SAndreas Eversberg }
723bd69ad1SAndreas Eversberg if (bestclock && bestclock != iclock_current) {
733bd69ad1SAndreas Eversberg /* new clock source selected, enable */
743bd69ad1SAndreas Eversberg if (*debug & DEBUG_CLOCK)
753bd69ad1SAndreas Eversberg printk(KERN_DEBUG "New clock source '%s' enable.\n",
763bd69ad1SAndreas Eversberg bestclock->name);
773bd69ad1SAndreas Eversberg bestclock->ctl(bestclock->priv, 1);
783bd69ad1SAndreas Eversberg }
793bd69ad1SAndreas Eversberg if (bestclock != iclock_current) {
803bd69ad1SAndreas Eversberg /* no clock received yet */
81ebf918cfSTina Ruchandani iclock_timestamp_valid = 0;
823bd69ad1SAndreas Eversberg }
833bd69ad1SAndreas Eversberg iclock_current = bestclock;
843bd69ad1SAndreas Eversberg }
853bd69ad1SAndreas Eversberg
863bd69ad1SAndreas Eversberg struct mISDNclock
mISDN_register_clock(char * name,int pri,clockctl_func_t * ctl,void * priv)873bd69ad1SAndreas Eversberg *mISDN_register_clock(char *name, int pri, clockctl_func_t *ctl, void *priv)
883bd69ad1SAndreas Eversberg {
893bd69ad1SAndreas Eversberg u_long flags;
903bd69ad1SAndreas Eversberg struct mISDNclock *iclock;
913bd69ad1SAndreas Eversberg
923bd69ad1SAndreas Eversberg if (*debug & (DEBUG_CORE | DEBUG_CLOCK))
933bd69ad1SAndreas Eversberg printk(KERN_DEBUG "%s: %s %d\n", __func__, name, pri);
943bd69ad1SAndreas Eversberg iclock = kzalloc(sizeof(struct mISDNclock), GFP_ATOMIC);
953bd69ad1SAndreas Eversberg if (!iclock) {
963bd69ad1SAndreas Eversberg printk(KERN_ERR "%s: No memory for clock entry.\n", __func__);
973bd69ad1SAndreas Eversberg return NULL;
983bd69ad1SAndreas Eversberg }
99*5c80c4fcSJustin Stitt strscpy(iclock->name, name, sizeof(iclock->name));
1003bd69ad1SAndreas Eversberg iclock->pri = pri;
1013bd69ad1SAndreas Eversberg iclock->priv = priv;
1023bd69ad1SAndreas Eversberg iclock->ctl = ctl;
1033bd69ad1SAndreas Eversberg write_lock_irqsave(&iclock_lock, flags);
1043bd69ad1SAndreas Eversberg list_add_tail(&iclock->list, &iclock_list);
1053bd69ad1SAndreas Eversberg select_iclock();
1063bd69ad1SAndreas Eversberg write_unlock_irqrestore(&iclock_lock, flags);
1073bd69ad1SAndreas Eversberg return iclock;
1083bd69ad1SAndreas Eversberg }
1093bd69ad1SAndreas Eversberg EXPORT_SYMBOL(mISDN_register_clock);
1103bd69ad1SAndreas Eversberg
1113bd69ad1SAndreas Eversberg void
mISDN_unregister_clock(struct mISDNclock * iclock)1123bd69ad1SAndreas Eversberg mISDN_unregister_clock(struct mISDNclock *iclock)
1133bd69ad1SAndreas Eversberg {
1143bd69ad1SAndreas Eversberg u_long flags;
1153bd69ad1SAndreas Eversberg
1163bd69ad1SAndreas Eversberg if (*debug & (DEBUG_CORE | DEBUG_CLOCK))
1173bd69ad1SAndreas Eversberg printk(KERN_DEBUG "%s: %s %d\n", __func__, iclock->name,
1183bd69ad1SAndreas Eversberg iclock->pri);
1193bd69ad1SAndreas Eversberg write_lock_irqsave(&iclock_lock, flags);
1203bd69ad1SAndreas Eversberg if (iclock_current == iclock) {
1213bd69ad1SAndreas Eversberg if (*debug & DEBUG_CLOCK)
1223bd69ad1SAndreas Eversberg printk(KERN_DEBUG
1233bd69ad1SAndreas Eversberg "Current clock source '%s' unregisters.\n",
1243bd69ad1SAndreas Eversberg iclock->name);
1253bd69ad1SAndreas Eversberg iclock->ctl(iclock->priv, 0);
1263bd69ad1SAndreas Eversberg }
1273bd69ad1SAndreas Eversberg list_del(&iclock->list);
1283bd69ad1SAndreas Eversberg select_iclock();
1293bd69ad1SAndreas Eversberg write_unlock_irqrestore(&iclock_lock, flags);
1303bd69ad1SAndreas Eversberg }
1313bd69ad1SAndreas Eversberg EXPORT_SYMBOL(mISDN_unregister_clock);
1323bd69ad1SAndreas Eversberg
1333bd69ad1SAndreas Eversberg void
mISDN_clock_update(struct mISDNclock * iclock,int samples,ktime_t * timestamp)134ebf918cfSTina Ruchandani mISDN_clock_update(struct mISDNclock *iclock, int samples, ktime_t *timestamp)
1353bd69ad1SAndreas Eversberg {
1363bd69ad1SAndreas Eversberg u_long flags;
137ebf918cfSTina Ruchandani ktime_t timestamp_now;
138ebf918cfSTina Ruchandani u16 delta;
1393bd69ad1SAndreas Eversberg
1403bd69ad1SAndreas Eversberg write_lock_irqsave(&iclock_lock, flags);
1413bd69ad1SAndreas Eversberg if (iclock_current != iclock) {
1423bd69ad1SAndreas Eversberg printk(KERN_ERR "%s: '%s' sends us clock updates, but we do "
1433bd69ad1SAndreas Eversberg "listen to '%s'. This is a bug!\n", __func__,
1443bd69ad1SAndreas Eversberg iclock->name,
1453bd69ad1SAndreas Eversberg iclock_current ? iclock_current->name : "nothing");
1463bd69ad1SAndreas Eversberg iclock->ctl(iclock->priv, 0);
1473bd69ad1SAndreas Eversberg write_unlock_irqrestore(&iclock_lock, flags);
1483bd69ad1SAndreas Eversberg return;
1493bd69ad1SAndreas Eversberg }
150ebf918cfSTina Ruchandani if (iclock_timestamp_valid) {
1513bd69ad1SAndreas Eversberg /* increment sample counter by given samples */
1523bd69ad1SAndreas Eversberg iclock_count += samples;
153ebf918cfSTina Ruchandani if (timestamp) { /* timestamp must be set, if function call is delayed */
154ebf918cfSTina Ruchandani iclock_timestamp = *timestamp;
155ebf918cfSTina Ruchandani } else {
156ebf918cfSTina Ruchandani iclock_timestamp = ktime_get();
157ebf918cfSTina Ruchandani }
1583bd69ad1SAndreas Eversberg } else {
1593bd69ad1SAndreas Eversberg /* calc elapsed time by system clock */
160ebf918cfSTina Ruchandani if (timestamp) { /* timestamp must be set, if function call is delayed */
161ebf918cfSTina Ruchandani timestamp_now = *timestamp;
162ebf918cfSTina Ruchandani } else {
163ebf918cfSTina Ruchandani timestamp_now = ktime_get();
1643bd69ad1SAndreas Eversberg }
165ebf918cfSTina Ruchandani delta = ktime_divns(ktime_sub(timestamp_now, iclock_timestamp),
166ebf918cfSTina Ruchandani (NSEC_PER_SEC / 8000));
1673bd69ad1SAndreas Eversberg /* add elapsed time to counter and set new timestamp */
168ebf918cfSTina Ruchandani iclock_count += delta;
169ebf918cfSTina Ruchandani iclock_timestamp = timestamp_now;
170ebf918cfSTina Ruchandani iclock_timestamp_valid = 1;
1713bd69ad1SAndreas Eversberg if (*debug & DEBUG_CLOCK)
1723bd69ad1SAndreas Eversberg printk("Received first clock from source '%s'.\n",
1733bd69ad1SAndreas Eversberg iclock_current ? iclock_current->name : "nothing");
1743bd69ad1SAndreas Eversberg }
1753bd69ad1SAndreas Eversberg write_unlock_irqrestore(&iclock_lock, flags);
1763bd69ad1SAndreas Eversberg }
1773bd69ad1SAndreas Eversberg EXPORT_SYMBOL(mISDN_clock_update);
1783bd69ad1SAndreas Eversberg
1793bd69ad1SAndreas Eversberg unsigned short
mISDN_clock_get(void)1803bd69ad1SAndreas Eversberg mISDN_clock_get(void)
1813bd69ad1SAndreas Eversberg {
1823bd69ad1SAndreas Eversberg u_long flags;
183ebf918cfSTina Ruchandani ktime_t timestamp_now;
184ebf918cfSTina Ruchandani u16 delta;
1853bd69ad1SAndreas Eversberg u16 count;
1863bd69ad1SAndreas Eversberg
1873bd69ad1SAndreas Eversberg read_lock_irqsave(&iclock_lock, flags);
1883bd69ad1SAndreas Eversberg /* calc elapsed time by system clock */
189ebf918cfSTina Ruchandani timestamp_now = ktime_get();
190ebf918cfSTina Ruchandani delta = ktime_divns(ktime_sub(timestamp_now, iclock_timestamp),
191ebf918cfSTina Ruchandani (NSEC_PER_SEC / 8000));
1923bd69ad1SAndreas Eversberg /* add elapsed time to counter */
193ebf918cfSTina Ruchandani count = iclock_count + delta;
1943bd69ad1SAndreas Eversberg read_unlock_irqrestore(&iclock_lock, flags);
1953bd69ad1SAndreas Eversberg return count;
1963bd69ad1SAndreas Eversberg }
1973bd69ad1SAndreas Eversberg EXPORT_SYMBOL(mISDN_clock_get);
198