drivers/net/fddi/skfp/hwt.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  * Timer Driver for FBI board (timer chip 82C54)
  19  */
  20
  21 /*
  22  * Modifications:
  23  *
  24  *      28-Jun-1994 sw  Edit v1.6.
  25  *                      MCA: Added support for the SK-NET FDDI-FM2 adapter. The
  26  *                       following functions have been added(+) or modified(*):
  27  *                       hwt_start(*), hwt_stop(*), hwt_restart(*), hwt_read(*)
  28  */
  29
  30 #include "h/types.h"
  31 #include "h/fddi.h"
  32 #include "h/smc.h"
  33
  34 #ifndef lint
  35 static const char ID_sccs[] = "@(#)hwt.c        1.13 97/04/23 (C) SK " ;
  36 #endif
  37
  38 /*
  39  * Prototypes of local functions.
  40  */
  41 /* 28-Jun-1994 sw - Note: hwt_restart() is also used in module 'drvfbi.c'. */
  42 /*static void hwt_restart() ; */
  43
  44 /************************
  45  *
  46  *      hwt_start
  47  *
  48  *      Start hardware timer (clock ticks are 16us).
  49  *
  50  *      void hwt_start(
  51  *              struct s_smc *smc,
  52  *              u_long time) ;
  53  * In
  54  *      smc - A pointer to the SMT Context structure.
  55  *
  56  *      time - The time in units of 16us to load the timer with.
  57  * Out
  58  *      Nothing.
  59  *
  60  ************************/
  61 #define HWT_MAX (65000)
  62
  63 void hwt_start(struct s_smc *smc, u_long time)
  64 {
  65         u_short cnt ;
  66
  67         if (time > HWT_MAX)
  68                 time = HWT_MAX ;
  69
  70         smc->hw.t_start = time ;
  71         smc->hw.t_stop = 0L ;
  72
  73         cnt = (u_short)time ;
  74         /*
  75          * if time < 16 us
  76          *      time = 16 us
  77          */
  78         if (!cnt)
  79                 cnt++ ;
  80
  81         outpd(ADDR(B2_TI_INI), (u_long) cnt * 200) ;    /* Load timer value. */
  82         outpw(ADDR(B2_TI_CRTL), TIM_START) ;            /* Start timer. */
  83
  84         smc->hw.timer_activ = TRUE ;
  85 }
  86
  87 /************************
  88  *
  89  *      hwt_stop
  90  *
  91  *      Stop hardware timer.
  92  *
  93  *      void hwt_stop(
  94  *              struct s_smc *smc) ;
  95  * In
  96  *      smc - A pointer to the SMT Context structure.
  97  * Out
  98  *      Nothing.
  99  *
 100  ************************/
 101 void hwt_stop(struct s_smc *smc)
 102 {
 103         outpw(ADDR(B2_TI_CRTL), TIM_STOP) ;
 104         outpw(ADDR(B2_TI_CRTL), TIM_CL_IRQ) ;
 105
 106         smc->hw.timer_activ = FALSE ;
 107 }
 108
 109 /************************
 110  *
 111  *      hwt_init
 112  *
 113  *      Initialize hardware timer.
 114  *
 115  *      void hwt_init(
 116  *              struct s_smc *smc) ;
 117  * In
 118  *      smc - A pointer to the SMT Context structure.
 119  * Out
 120  *      Nothing.
 121  *
 122  ************************/
 123 void hwt_init(struct s_smc *smc)
 124 {
 125         smc->hw.t_start = 0 ;
 126         smc->hw.t_stop  = 0 ;
 127         smc->hw.timer_activ = FALSE ;
 128
 129         hwt_restart(smc) ;
 130 }
 131
 132 /************************
 133  *
 134  *      hwt_restart
 135  *
 136  *      Clear timer interrupt.
 137  *
 138  *      void hwt_restart(
 139  *              struct s_smc *smc) ;
 140  * In
 141  *      smc - A pointer to the SMT Context structure.
 142  * Out
 143  *      Nothing.
 144  *
 145  ************************/
 146 void hwt_restart(struct s_smc *smc)
 147 {
 148         hwt_stop(smc) ;
 149 }
 150
 151 /************************
 152  *
 153  *      hwt_read
 154  *
 155  *      Stop hardware timer and read time elapsed since last start.
 156  *
 157  *      u_long hwt_read(smc) ;
 158  * In
 159  *      smc - A pointer to the SMT Context structure.
 160  * Out
 161  *      The elapsed time since last start in units of 16us.
 162  *
 163  ************************/
 164 u_long hwt_read(struct s_smc *smc)
 165 {
 166         u_short tr ;
 167         u_long  is ;
 168
 169         if (smc->hw.timer_activ) {
 170                 hwt_stop(smc) ;
 171                 tr = (u_short)((inpd(ADDR(B2_TI_VAL))/200) & 0xffff) ;
 172
 173                 is = GET_ISR() ;
 174                 /* Check if timer expired (or wraparound). */
 175                 if ((tr > smc->hw.t_start) || (is & IS_TIMINT)) {
 176                         hwt_restart(smc) ;
 177                         smc->hw.t_stop = smc->hw.t_start ;
 178                 }
 179                 else
 180                         smc->hw.t_stop = smc->hw.t_start - tr ;
 181         }
 182         return smc->hw.t_stop;
 183 }
 184
 185 #ifdef  PCI
 186 /************************
 187  *
 188  *      hwt_quick_read
 189  *
 190  *      Stop hardware timer and read timer value and start the timer again.
 191  *
 192  *      u_long hwt_read(smc) ;
 193  * In
 194  *      smc - A pointer to the SMT Context structure.
 195  * Out
 196  *      current timer value in units of 80ns.
 197  *
 198  ************************/
 199 u_long hwt_quick_read(struct s_smc *smc)
 200 {
 201         u_long interval ;
 202         u_long time ;
 203
 204         interval = inpd(ADDR(B2_TI_INI)) ;
 205         outpw(ADDR(B2_TI_CRTL), TIM_STOP) ;
 206         time = inpd(ADDR(B2_TI_VAL)) ;
 207         outpd(ADDR(B2_TI_INI),time) ;
 208         outpw(ADDR(B2_TI_CRTL), TIM_START) ;
 209         outpd(ADDR(B2_TI_INI),interval) ;
 210
 211         return time;
 212 }
 213
 214 /************************
 215  *
 216  *      hwt_wait_time(smc,start,duration)
 217  *
 218  *      This function returnes after the amount of time is elapsed
 219  *      since the start time.
 220  *
 221  * para start           start time
 222  *      duration        time to wait
 223  *
 224  * NOTE: The function will return immediately, if the timer is not
 225  *       started
 226  ************************/
 227 void hwt_wait_time(struct s_smc *smc, u_long start, long int duration)
 228 {
 229         long    diff ;
 230         long    interval ;
 231         int     wrapped ;
 232
 233         /*
 234          * check if timer is running
 235          */
 236         if (smc->hw.timer_activ == FALSE ||
 237                 hwt_quick_read(smc) == hwt_quick_read(smc)) {
 238                 return ;
 239         }
 240
 241         interval = inpd(ADDR(B2_TI_INI)) ;
 242         if (interval > duration) {
 243                 do {
 244                         diff = (long)(start - hwt_quick_read(smc)) ;
 245                         if (diff < 0) {
 246                                 diff += interval ;
 247                         }
 248                 } while (diff <= duration) ;
 249         }
 250         else {
 251                 diff = interval ;
 252                 wrapped = 0 ;
 253                 do {
 254                         if (!wrapped) {
 255                                 if (hwt_quick_read(smc) >= start) {
 256                                         diff += interval ;
 257                                         wrapped = 1 ;
 258                                 }
 259                         }
 260                         else {
 261                                 if (hwt_quick_read(smc) < start) {
 262                                         wrapped = 0 ;
 263                                 }
 264                         }
 265                 } while (diff <= duration) ;
 266         }
 267 }
 268 #endif
 269