drivers/net/fddi/skfp/smttimer.c

   1 /******************************************************************************
   2  *
   3  *      (C)Copyright 1998,1999 SysKonnect,
   4  *      a business unit of Schneider & Koch & Co. Datensysteme GmbH.
   5  *
   6  *      See the file "skfddi.c" for further information.
   7  *
   8  *      This program is free software; you can redistribute it and/or modify
   9  *      it under the terms of the GNU General Public License as published by
  10  *      the Free Software Foundation; either version 2 of the License, or
  11  *      (at your option) any later version.
  12  *
  13  *      The information in this file is provided "AS IS" without warranty.
  14  *
  15  ******************************************************************************/
  16
  17 /*
  18         SMT timer
  19 */
  20
  21 #include "h/types.h"
  22 #include "h/fddi.h"
  23 #include "h/smc.h"
  24
  25 #ifndef lint
  26 static const char ID_sccs[] = "@(#)smttimer.c   2.4 97/08/04 (C) SK " ;
  27 #endif
  28
  29 static void timer_done(struct s_smc *smc, int restart);
  30
  31 void smt_timer_init(struct s_smc *smc)
  32 {
  33         smc->t.st_queue = NULL;
  34         smc->t.st_fast.tm_active = FALSE ;
  35         smc->t.st_fast.tm_next = NULL;
  36         hwt_init(smc) ;
  37 }
  38
  39 void smt_timer_stop(struct s_smc *smc, struct smt_timer *timer)
  40 {
  41         struct smt_timer        **prev ;
  42         struct smt_timer        *tm ;
  43
  44         /*
  45          * remove timer from queue
  46          */
  47         timer->tm_active = FALSE ;
  48         if (smc->t.st_queue == timer && !timer->tm_next) {
  49                 hwt_stop(smc) ;
  50         }
  51         for (prev = &smc->t.st_queue ; (tm = *prev) ; prev = &tm->tm_next ) {
  52                 if (tm == timer) {
  53                         *prev = tm->tm_next ;
  54                         if (tm->tm_next) {
  55                                 tm->tm_next->tm_delta += tm->tm_delta ;
  56                         }
  57                         return ;
  58                 }
  59         }
  60 }
  61
  62 void smt_timer_start(struct s_smc *smc, struct smt_timer *timer, u_long time,
  63                      u_long token)
  64 {
  65         struct smt_timer        **prev ;
  66         struct smt_timer        *tm ;
  67         u_long                  delta = 0 ;
  68
  69         time /= 16 ;            /* input is uS, clock ticks are 16uS */
  70         if (!time)
  71                 time = 1 ;
  72         smt_timer_stop(smc,timer) ;
  73         timer->tm_smc = smc ;
  74         timer->tm_token = token ;
  75         timer->tm_active = TRUE ;
  76         if (!smc->t.st_queue) {
  77                 smc->t.st_queue = timer ;
  78                 timer->tm_next = NULL;
  79                 timer->tm_delta = time ;
  80                 hwt_start(smc,time) ;
  81                 return ;
  82         }
  83         /*
  84          * timer correction
  85          */
  86         timer_done(smc,0) ;
  87
  88         /*
  89          * find position in queue
  90          */
  91         delta = 0 ;
  92         for (prev = &smc->t.st_queue ; (tm = *prev) ; prev = &tm->tm_next ) {
  93                 if (delta + tm->tm_delta > time) {
  94                         break ;
  95                 }
  96                 delta += tm->tm_delta ;
  97         }
  98         /* insert in queue */
  99         *prev = timer ;
 100         timer->tm_next = tm ;
 101         timer->tm_delta = time - delta ;
 102         if (tm)
 103                 tm->tm_delta -= timer->tm_delta ;
 104         /*
 105          * start new with first
 106          */
 107         hwt_start(smc,smc->t.st_queue->tm_delta) ;
 108 }
 109
 110 void smt_force_irq(struct s_smc *smc)
 111 {
 112         smt_timer_start(smc,&smc->t.st_fast,32L, EV_TOKEN(EVENT_SMT,SM_FAST));
 113 }
 114
 115 void smt_timer_done(struct s_smc *smc)
 116 {
 117         timer_done(smc,1) ;
 118 }
 119
 120 static void timer_done(struct s_smc *smc, int restart)
 121 {
 122         u_long                  delta ;
 123         struct smt_timer        *tm ;
 124         struct smt_timer        *next ;
 125         struct smt_timer        **last ;
 126         int                     done = 0 ;
 127
 128         delta = hwt_read(smc) ;
 129         last = &smc->t.st_queue ;
 130         tm = smc->t.st_queue ;
 131         while (tm && !done) {
 132                 if (delta >= tm->tm_delta) {
 133                         tm->tm_active = FALSE ;
 134                         delta -= tm->tm_delta ;
 135                         last = &tm->tm_next ;
 136                         tm = tm->tm_next ;
 137                 }
 138                 else {
 139                         tm->tm_delta -= delta ;
 140                         delta = 0 ;
 141                         done = 1 ;
 142                 }
 143         }
 144         *last = NULL;
 145         next = smc->t.st_queue ;
 146         smc->t.st_queue = tm ;
 147
 148         for ( tm = next ; tm ; tm = next) {
 149                 next = tm->tm_next ;
 150                 timer_event(smc,tm->tm_token) ;
 151         }
 152
 153         if (restart && smc->t.st_queue)
 154                 hwt_start(smc,smc->t.st_queue->tm_delta) ;
 155 }
 156