examples/timer.c

   1 /*
   2  * (C) Copyright 2000
   3  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   4  *
   5  * See file CREDITS for list of people who contributed to this
   6  * project.
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as
  10  * published by the Free Software Foundation; either version 2 of
  11  * the License, or (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  21  * MA 02111-1307 USA
  22  */
  23
  24 #include <common.h>
  25 #include <commproc.h>
  26 #include <mpc8xx_irq.h>
  27 #include <exports.h>
  28
  29 DECLARE_GLOBAL_DATA_PTR;
  30
  31 #undef  DEBUG
  32
  33 #define TIMER_PERIOD    1000000         /* 1 second clock */
  34
  35 static void timer_handler (void *arg);
  36
  37
  38 /* Access functions for the Machine State Register */
  39 static __inline__ unsigned long get_msr(void)
  40 {
  41     unsigned long msr;
  42
  43     asm volatile("mfmsr %0" : "=r" (msr) :);
  44     return msr;
  45 }
  46
  47 static __inline__ void set_msr(unsigned long msr)
  48 {
  49     asm volatile("mtmsr %0" : : "r" (msr));
  50 }
  51
  52 /*
  53  * Definitions to access the CPM Timer registers
  54  * See 8xx_immap.h for Internal Memory Map layout,
  55  * and commproc.h for CPM Interrupt vectors (aka "IRQ"s)
  56  */
  57
  58 typedef struct tid_8xx_cpmtimer_s {
  59   int            cpm_vec;       /* CPM Interrupt Vector for this timer  */
  60   ushort        *tgcrp;         /* Pointer to Timer Global Config Reg.  */
  61   ushort        *tmrp;          /* Pointer to Timer Mode Register       */
  62   ushort        *trrp;          /* Pointer to Timer Reference Register  */
  63   ushort        *tcrp;          /* Pointer to Timer Capture Register    */
  64   ushort        *tcnp;          /* Pointer to Timer Counter Register    */
  65   ushort        *terp;          /* Pointer to Timer Event Register      */
  66 } tid_8xx_cpmtimer_t;
  67
  68 #ifndef CLOCKRATE
  69 #  define CLOCKRATE 64
  70 #endif
  71
  72 #define CPMT_CLOCK_DIV          16
  73 #define CPMT_MAX_PRESCALER      256
  74 #define CPMT_MAX_REFERENCE      65535   /* max. unsigned short */
  75
  76 #define CPMT_MAX_TICKS          (CPMT_MAX_REFERENCE * CPMT_MAX_PRESCALER)
  77 #define CPMT_MAX_TICKS_WITH_DIV (CPMT_MAX_REFERENCE * CPMT_MAX_PRESCALER * CPMT_CLOCK_DIV)
  78 #define CPMT_MAX_INTERVAL       (CPMT_MAX_TICKS_WITH_DIV / CLOCKRATE)
  79
  80 /* For now: always use max. prescaler value */
  81 #define CPMT_PRESCALER          (CPMT_MAX_PRESCALER)
  82
  83 /* CPM Timer Event Register Bits */
  84 #define CPMT_EVENT_CAP          0x0001  /* Capture Event                */
  85 #define CPMT_EVENT_REF          0x0002  /* Reference Counter Event      */
  86
  87 /* CPM Timer Global Config Register */
  88 #define CPMT_GCR_RST            0x0001  /* Reset  Timer                 */
  89 #define CPMT_GCR_STP            0x0002  /* Stop   Timer                 */
  90 #define CPMT_GCR_FRZ            0x0004  /* Freeze Timer                 */
  91 #define CPMT_GCR_GM_CAS         0x0008  /* Gate Mode / Cascade Timers   */
  92 #define CPMT_GCR_MASK           (CPMT_GCR_RST|CPMT_GCR_STP|CPMT_GCR_FRZ|CPMT_GCR_GM_CAS)
  93
  94 /* CPM Timer Mode register */
  95 #define CPMT_MR_GE              0x0001  /* Gate Enable                  */
  96 #define CPMT_MR_ICLK_CASC       0x0000  /* Clock internally cascaded    */
  97 #define CPMT_MR_ICLK_CLK        0x0002  /* Clock = system clock         */
  98 #define CPMT_MR_ICLK_CLKDIV     0x0004  /* Clock = system clock / 16    */
  99 #define CPMT_MR_ICLK_TIN        0x0006  /* Clock = TINx signal          */
 100 #define CPMT_MR_FRR             0x0008  /* Free Run / Restart           */
 101 #define CPMT_MR_ORI             0x0010  /* Out. Reference Interrupt En. */
 102 #define CPMT_MR_OM              0x0020  /* Output Mode                  */
 103 #define CPMT_MR_CE_DIS          0x0000  /* Capture/Interrupt disabled   */
 104 #define CPMT_MR_CE_RISE         0x0040  /* Capt./Interr. on rising  TIN */
 105 #define CPMT_MR_CE_FALL         0x0080  /* Capt./Interr. on falling TIN */
 106 #define CPMT_MR_CE_ANY          0x00C0  /* Capt./Interr. on any TIN edge*/
 107
 108
 109 /*
 110  * which CPM timer to use - index starts at 0 (= timer 1)
 111  */
 112 #define TID_TIMER_ID    0       /* use CPM timer 1              */
 113
 114 void setPeriod (tid_8xx_cpmtimer_t *hwp, ulong interval);
 115
 116 static char *usage = "\n[q, b, e, ?] ";
 117
 118 int timer (int argc, char *argv[])
 119 {
 120         cpmtimer8xx_t *cpmtimerp;       /* Pointer to the CPM Timer structure   */
 121         tid_8xx_cpmtimer_t hw;
 122         tid_8xx_cpmtimer_t *hwp = &hw;
 123         int c;
 124         int running;
 125
 126         app_startup(argv);
 127
 128         /* Pointer to CPM Timer structure */
 129         cpmtimerp = &((immap_t *) gd->bd->bi_immr_base)->im_cpmtimer;
 130
 131         printf ("TIMERS=0x%x\n", (unsigned) cpmtimerp);
 132
 133         /* Initialize pointers depending on which timer we use */
 134         switch (TID_TIMER_ID) {
 135         case 0:
 136                 hwp->tmrp = &(cpmtimerp->cpmt_tmr1);
 137                 hwp->trrp = &(cpmtimerp->cpmt_trr1);
 138                 hwp->tcrp = &(cpmtimerp->cpmt_tcr1);
 139                 hwp->tcnp = &(cpmtimerp->cpmt_tcn1);
 140                 hwp->terp = &(cpmtimerp->cpmt_ter1);
 141                 hwp->cpm_vec = CPMVEC_TIMER1;
 142                 break;
 143         case 1:
 144                 hwp->tmrp = &(cpmtimerp->cpmt_tmr2);
 145                 hwp->trrp = &(cpmtimerp->cpmt_trr2);
 146                 hwp->tcrp = &(cpmtimerp->cpmt_tcr2);
 147                 hwp->tcnp = &(cpmtimerp->cpmt_tcn2);
 148                 hwp->terp = &(cpmtimerp->cpmt_ter2);
 149                 hwp->cpm_vec = CPMVEC_TIMER2;
 150                 break;
 151         case 2:
 152                 hwp->tmrp = &(cpmtimerp->cpmt_tmr3);
 153                 hwp->trrp = &(cpmtimerp->cpmt_trr3);
 154                 hwp->tcrp = &(cpmtimerp->cpmt_tcr3);
 155                 hwp->tcnp = &(cpmtimerp->cpmt_tcn3);
 156                 hwp->terp = &(cpmtimerp->cpmt_ter3);
 157                 hwp->cpm_vec = CPMVEC_TIMER3;
 158                 break;
 159         case 3:
 160                 hwp->tmrp = &(cpmtimerp->cpmt_tmr4);
 161                 hwp->trrp = &(cpmtimerp->cpmt_trr4);
 162                 hwp->tcrp = &(cpmtimerp->cpmt_tcr4);
 163                 hwp->tcnp = &(cpmtimerp->cpmt_tcn4);
 164                 hwp->terp = &(cpmtimerp->cpmt_ter4);
 165                 hwp->cpm_vec = CPMVEC_TIMER4;
 166                 break;
 167         }
 168
 169         hwp->tgcrp = &cpmtimerp->cpmt_tgcr;
 170
 171         printf ("Using timer %d\n"
 172                         "tgcr @ 0x%x, tmr @ 0x%x, trr @ 0x%x,"
 173                         " tcr @ 0x%x, tcn @ 0x%x, ter @ 0x%x\n",
 174                         TID_TIMER_ID + 1,
 175                         (unsigned) hwp->tgcrp,
 176                         (unsigned) hwp->tmrp,
 177                         (unsigned) hwp->trrp,
 178                         (unsigned) hwp->tcrp,
 179                         (unsigned) hwp->tcnp,
 180                         (unsigned) hwp->terp
 181                         );
 182
 183         /* reset timer    */
 184         *hwp->tgcrp &= ~(CPMT_GCR_MASK << TID_TIMER_ID);
 185
 186         /* clear all events */
 187         *hwp->terp = (CPMT_EVENT_CAP | CPMT_EVENT_REF);
 188
 189         printf (usage);
 190         running = 0;
 191         while ((c = getc()) != 'q') {
 192             if (c == 'b') {
 193
 194                 setPeriod (hwp, TIMER_PERIOD);  /* Set period and start ticking */
 195
 196                 /* Install interrupt handler (enable timer in CIMR) */
 197                 install_hdlr (hwp->cpm_vec, timer_handler, hwp);
 198
 199                 printf ("Enabling timer\n");
 200
 201                 /* enable timer */
 202                 *hwp->tgcrp |= (CPMT_GCR_RST << TID_TIMER_ID);
 203                 running = 1;
 204
 205 #ifdef  DEBUG
 206                 printf ("tgcr=0x%x, tmr=0x%x, trr=0x%x,"
 207                         " tcr=0x%x, tcn=0x%x, ter=0x%x\n",
 208                                 *hwp->tgcrp, *hwp->tmrp, *hwp->trrp,
 209                                 *hwp->tcrp,  *hwp->tcnp, *hwp->terp
 210                                 );
 211 #endif
 212             } else if (c == 'e') {
 213
 214                 printf ("Stopping timer\n");
 215
 216                 *hwp->tgcrp &= ~(CPMT_GCR_MASK << TID_TIMER_ID);
 217                 running = 0;
 218
 219 #ifdef  DEBUG
 220                 printf ("tgcr=0x%x, tmr=0x%x, trr=0x%x,"
 221                         " tcr=0x%x, tcn=0x%x, ter=0x%x\n",
 222                                 *hwp->tgcrp, *hwp->tmrp, *hwp->trrp,
 223                                 *hwp->tcrp,  *hwp->tcnp, *hwp->terp
 224                         );
 225 #endif
 226                 /* Uninstall interrupt handler */
 227                 free_hdlr (hwp->cpm_vec);
 228
 229             } else if (c == '?') {
 230 #ifdef  DEBUG
 231                 cpic8xx_t *cpm_icp = &((immap_t *) gd->bd->bi_immr_base)->im_cpic;
 232                 sysconf8xx_t *siup = &((immap_t *) gd->bd->bi_immr_base)->im_siu_conf;
 233 #endif
 234
 235                 printf ("\ntgcr=0x%x, tmr=0x%x, trr=0x%x,"
 236                         " tcr=0x%x, tcn=0x%x, ter=0x%x\n",
 237                                 *hwp->tgcrp, *hwp->tmrp, *hwp->trrp,
 238                                 *hwp->tcrp,  *hwp->tcnp, *hwp->terp
 239                         );
 240 #ifdef  DEBUG
 241                 printf ("SIUMCR=0x%08lx, SYPCR=0x%08lx,"
 242                         " SIMASK=0x%08lx, SIPEND=0x%08lx\n",
 243                                 siup->sc_siumcr,
 244                                 siup->sc_sypcr,
 245                                 siup->sc_simask,
 246                                 siup->sc_sipend
 247                         );
 248
 249                 printf ("CIMR=0x%08lx, CICR=0x%08lx, CIPR=0x%08lx\n",
 250                         cpm_icp->cpic_cimr,
 251                         cpm_icp->cpic_cicr,
 252                         cpm_icp->cpic_cipr
 253                         );
 254 #endif
 255             } else {
 256                 printf ("\nEnter: q - quit, b - start timer, e - stop timer, ? - get status\n");
 257             }
 258             printf (usage);
 259         }
 260         if (running) {
 261                 printf ("Stopping timer\n");
 262                 *hwp->tgcrp &= ~(CPMT_GCR_MASK << TID_TIMER_ID);
 263                 free_hdlr (hwp->cpm_vec);
 264         }
 265
 266         return (0);
 267 }
 268
 269
 270 /* Set period in microseconds and start.
 271  * Truncate to maximum period if more than this is requested - but warn about it.
 272  */
 273
 274 void setPeriod (tid_8xx_cpmtimer_t *hwp, ulong interval)
 275 {
 276         unsigned short prescaler;
 277         unsigned long ticks;
 278
 279         printf ("Set interval %ld us\n", interval);
 280
 281         /* Warn if requesting longer period than possible */
 282         if (interval > CPMT_MAX_INTERVAL) {
 283                 printf ("Truncate interval %ld to maximum (%d)\n",
 284                                 interval, CPMT_MAX_INTERVAL);
 285                 interval = CPMT_MAX_INTERVAL;
 286         }
 287         /*
 288          * Check if we want to use clock divider:
 289          * Since the reference counter can be incremented only in integer steps,
 290          * we try to keep it as big as possible to allow the resulting period to be
 291          * as precise as possible.
 292          */
 293         /* prescaler, enable interrupt, restart after ref count is reached */
 294         prescaler = (ushort) ((CPMT_PRESCALER - 1) << 8) |
 295                         CPMT_MR_ORI |
 296                         CPMT_MR_FRR;
 297
 298         ticks = ((ulong) CLOCKRATE * interval);
 299
 300         if (ticks > CPMT_MAX_TICKS) {
 301                 ticks /= CPMT_CLOCK_DIV;
 302                 prescaler |= CPMT_MR_ICLK_CLKDIV;       /* use system clock divided by 16 */
 303         } else {
 304                 prescaler |= CPMT_MR_ICLK_CLK;  /* use system clock without divider */
 305         }
 306
 307 #ifdef  DEBUG
 308         printf ("clock/%d, prescale factor %d, reference %ld, ticks %ld\n",
 309                         (ticks > CPMT_MAX_TICKS) ? CPMT_CLOCK_DIV : 1,
 310                         CPMT_PRESCALER,
 311                         (ticks / CPMT_PRESCALER),
 312                         ticks
 313                         );
 314 #endif
 315
 316         /* set prescaler register */
 317         *hwp->tmrp = prescaler;
 318
 319         /* clear timer counter */
 320         *hwp->tcnp = 0;
 321
 322         /* set reference register */
 323         *hwp->trrp = (unsigned short) (ticks / CPMT_PRESCALER);
 324
 325 #ifdef  DEBUG
 326         printf ("tgcr=0x%x, tmr=0x%x, trr=0x%x,"
 327                 " tcr=0x%x, tcn=0x%x, ter=0x%x\n",
 328                         *hwp->tgcrp, *hwp->tmrp, *hwp->trrp,
 329                         *hwp->tcrp,  *hwp->tcnp, *hwp->terp
 330                 );
 331 #endif
 332 }
 333
 334 /*
 335  * Handler for CPMVEC_TIMER1 interrupt
 336  */
 337 static
 338 void timer_handler (void *arg)
 339 {
 340         tid_8xx_cpmtimer_t *hwp = (tid_8xx_cpmtimer_t *)arg;
 341
 342         /* printf ("** TER1=%04x ** ", *hwp->terp); */
 343
 344         /* just for demonstration */
 345         printf (".");
 346
 347         /* clear all possible events: Ref. and Cap. */
 348         *hwp->terp = (CPMT_EVENT_CAP | CPMT_EVENT_REF);
 349 }