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  
21  static void timer_done(struct s_smc *smc, int restart);
22  
smt_timer_init(struct s_smc * smc)23  void 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  
smt_timer_stop(struct s_smc * smc,struct smt_timer * timer)31  void 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  
smt_timer_start(struct s_smc * smc,struct smt_timer * timer,u_long time,u_long token)54  void 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  
smt_force_irq(struct s_smc * smc)102  void 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  
smt_timer_done(struct s_smc * smc)107  void smt_timer_done(struct s_smc *smc)
108  {
109  	timer_done(smc,1) ;
110  }
111  
timer_done(struct s_smc * smc,int restart)112  static 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  
149