xref: /openbmc/linux/drivers/net/fddi/skfp/smttimer.c (revision d9fd5a71)
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 
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 
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 
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 
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 
107 void smt_timer_done(struct s_smc *smc)
108 {
109 	timer_done(smc,1) ;
110 }
111 
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