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
149