smttimer.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/******************************************************************************
  3 *
  4 *	(C)Copyright 1998,1999 SysKonnect,
  5 *	a business unit of Schneider & Koch & Co. Datensysteme GmbH.
  6 *
  7 *	See the file "skfddi.c" for further information.
  8 *
  9 *	The information in this file is provided "AS IS" without warranty.
 10 *
 11 ******************************************************************************/
 12
 13/*
 14	SMT timer
 15*/
 16
 17#include "h/types.h"
 18#include "h/fddi.h"
 19#include "h/smc.h"
 20
 21static void timer_done(struct s_smc *smc, int restart);
 22
 23void smt_timer_init(struct s_smc *smc)
 24{
 25	smc->t.st_queue = NULL;
 26	smc->t.st_fast.tm_active = FALSE ;
 27	smc->t.st_fast.tm_next = NULL;
 28	hwt_init(smc) ;
 29}
 30
 31void smt_timer_stop(struct s_smc *smc, struct smt_timer *timer)
 32{
 33	struct smt_timer	**prev ;
 34	struct smt_timer	*tm ;
 35
 36	/*
 37	 * remove timer from queue
 38	 */
 39	timer->tm_active = FALSE ;
 40	if (smc->t.st_queue == timer && !timer->tm_next) {
 41		hwt_stop(smc) ;
 42	}
 43	for (prev = &smc->t.st_queue ; (tm = *prev) ; prev = &tm->tm_next ) {
 44		if (tm == timer) {
 45			*prev = tm->tm_next ;
 46			if (tm->tm_next) {
 47				tm->tm_next->tm_delta += tm->tm_delta ;
 48			}
 49			return ;
 50		}
 51	}
 52}
 53
 54void smt_timer_start(struct s_smc *smc, struct smt_timer *timer, u_long time,
 55		     u_long token)
 56{
 57	struct smt_timer	**prev ;
 58	struct smt_timer	*tm ;
 59	u_long			delta = 0 ;
 60
 61	time /= 16 ;		/* input is uS, clock ticks are 16uS */
 62	if (!time)
 63		time = 1 ;
 64	smt_timer_stop(smc,timer) ;
 65	timer->tm_smc = smc ;
 66	timer->tm_token = token ;
 67	timer->tm_active = TRUE ;
 68	if (!smc->t.st_queue) {
 69		smc->t.st_queue = timer ;
 70		timer->tm_next = NULL;
 71		timer->tm_delta = time ;
 72		hwt_start(smc,time) ;
 73		return ;
 74	}
 75	/*
 76	 * timer correction
 77	 */
 78	timer_done(smc,0) ;
 79
 80	/*
 81	 * find position in queue
 82	 */
 83	delta = 0 ;
 84	for (prev = &smc->t.st_queue ; (tm = *prev) ; prev = &tm->tm_next ) {
 85		if (delta + tm->tm_delta > time) {
 86			break ;
 87		}
 88		delta += tm->tm_delta ;
 89	}
 90	/* insert in queue */
 91	*prev = timer ;
 92	timer->tm_next = tm ;
 93	timer->tm_delta = time - delta ;
 94	if (tm)
 95		tm->tm_delta -= timer->tm_delta ;
 96	/*
 97	 * start new with first
 98	 */
 99	hwt_start(smc,smc->t.st_queue->tm_delta) ;
100}
101
102void smt_force_irq(struct s_smc *smc)
103{
104	smt_timer_start(smc,&smc->t.st_fast,32L, EV_TOKEN(EVENT_SMT,SM_FAST)); 
105}
106
107void smt_timer_done(struct s_smc *smc)
108{
109	timer_done(smc,1) ;
110}
111
112static void timer_done(struct s_smc *smc, int restart)
113{
114	u_long			delta ;
115	struct smt_timer	*tm ;
116	struct smt_timer	*next ;
117	struct smt_timer	**last ;
118	int			done = 0 ;
119
120	delta = hwt_read(smc) ;
121	last = &smc->t.st_queue ;
122	tm = smc->t.st_queue ;
123	while (tm && !done) {
124		if (delta >= tm->tm_delta) {
125			tm->tm_active = FALSE ;
126			delta -= tm->tm_delta ;
127			last = &tm->tm_next ;
128			tm = tm->tm_next ;
129		}
130		else {
131			tm->tm_delta -= delta ;
132			delta = 0 ;
133			done = 1 ;
134		}
135	}
136	*last = NULL;
137	next = smc->t.st_queue ;
138	smc->t.st_queue = tm ;
139
140	for ( tm = next ; tm ; tm = next) {
141		next = tm->tm_next ;
142		timer_event(smc,tm->tm_token) ;
143	}
144
145	if (restart && smc->t.st_queue)
146		hwt_start(smc,smc->t.st_queue->tm_delta) ;
147}
148