xref: /openbmc/linux/drivers/net/fddi/skfp/smttimer.c (revision 4419617e)
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 #ifndef	lint
22 static const char ID_sccs[] = "@(#)smttimer.c	2.4 97/08/04 (C) SK " ;
23 #endif
24 
25 static void timer_done(struct s_smc *smc, int restart);
26 
27 void smt_timer_init(struct s_smc *smc)
28 {
29 	smc->t.st_queue = NULL;
30 	smc->t.st_fast.tm_active = FALSE ;
31 	smc->t.st_fast.tm_next = NULL;
32 	hwt_init(smc) ;
33 }
34 
35 void smt_timer_stop(struct s_smc *smc, struct smt_timer *timer)
36 {
37 	struct smt_timer	**prev ;
38 	struct smt_timer	*tm ;
39 
40 	/*
41 	 * remove timer from queue
42 	 */
43 	timer->tm_active = FALSE ;
44 	if (smc->t.st_queue == timer && !timer->tm_next) {
45 		hwt_stop(smc) ;
46 	}
47 	for (prev = &smc->t.st_queue ; (tm = *prev) ; prev = &tm->tm_next ) {
48 		if (tm == timer) {
49 			*prev = tm->tm_next ;
50 			if (tm->tm_next) {
51 				tm->tm_next->tm_delta += tm->tm_delta ;
52 			}
53 			return ;
54 		}
55 	}
56 }
57 
58 void smt_timer_start(struct s_smc *smc, struct smt_timer *timer, u_long time,
59 		     u_long token)
60 {
61 	struct smt_timer	**prev ;
62 	struct smt_timer	*tm ;
63 	u_long			delta = 0 ;
64 
65 	time /= 16 ;		/* input is uS, clock ticks are 16uS */
66 	if (!time)
67 		time = 1 ;
68 	smt_timer_stop(smc,timer) ;
69 	timer->tm_smc = smc ;
70 	timer->tm_token = token ;
71 	timer->tm_active = TRUE ;
72 	if (!smc->t.st_queue) {
73 		smc->t.st_queue = timer ;
74 		timer->tm_next = NULL;
75 		timer->tm_delta = time ;
76 		hwt_start(smc,time) ;
77 		return ;
78 	}
79 	/*
80 	 * timer correction
81 	 */
82 	timer_done(smc,0) ;
83 
84 	/*
85 	 * find position in queue
86 	 */
87 	delta = 0 ;
88 	for (prev = &smc->t.st_queue ; (tm = *prev) ; prev = &tm->tm_next ) {
89 		if (delta + tm->tm_delta > time) {
90 			break ;
91 		}
92 		delta += tm->tm_delta ;
93 	}
94 	/* insert in queue */
95 	*prev = timer ;
96 	timer->tm_next = tm ;
97 	timer->tm_delta = time - delta ;
98 	if (tm)
99 		tm->tm_delta -= timer->tm_delta ;
100 	/*
101 	 * start new with first
102 	 */
103 	hwt_start(smc,smc->t.st_queue->tm_delta) ;
104 }
105 
106 void smt_force_irq(struct s_smc *smc)
107 {
108 	smt_timer_start(smc,&smc->t.st_fast,32L, EV_TOKEN(EVENT_SMT,SM_FAST));
109 }
110 
111 void smt_timer_done(struct s_smc *smc)
112 {
113 	timer_done(smc,1) ;
114 }
115 
116 static void timer_done(struct s_smc *smc, int restart)
117 {
118 	u_long			delta ;
119 	struct smt_timer	*tm ;
120 	struct smt_timer	*next ;
121 	struct smt_timer	**last ;
122 	int			done = 0 ;
123 
124 	delta = hwt_read(smc) ;
125 	last = &smc->t.st_queue ;
126 	tm = smc->t.st_queue ;
127 	while (tm && !done) {
128 		if (delta >= tm->tm_delta) {
129 			tm->tm_active = FALSE ;
130 			delta -= tm->tm_delta ;
131 			last = &tm->tm_next ;
132 			tm = tm->tm_next ;
133 		}
134 		else {
135 			tm->tm_delta -= delta ;
136 			delta = 0 ;
137 			done = 1 ;
138 		}
139 	}
140 	*last = NULL;
141 	next = smc->t.st_queue ;
142 	smc->t.st_queue = tm ;
143 
144 	for ( tm = next ; tm ; tm = next) {
145 		next = tm->tm_next ;
146 		timer_event(smc,tm->tm_token) ;
147 	}
148 
149 	if (restart && smc->t.st_queue)
150 		hwt_start(smc,smc->t.st_queue->tm_delta) ;
151 }
152 
153