examples/standalone/timer.c

   1 /*
   2  * (C) Copyright 2000
   3  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   4  *
   5  * SPDX-License-Identifier:     GPL-2.0+
   6  */
   7
   8 #include <common.h>
   9 #include <commproc.h>
  10 #include <mpc8xx_irq.h>
  11 #include <exports.h>
  12
  13 DECLARE_GLOBAL_DATA_PTR;
  14
  15 #undef  DEBUG
  16
  17 #define TIMER_PERIOD    1000000         /* 1 second clock */
  18
  19 static void timer_handler (void *arg);
  20
  21
  22 /* Access functions for the Machine State Register */
  23 static __inline__ unsigned long get_msr(void)
  24 {
  25     unsigned long msr;
  26
  27     asm volatile("mfmsr %0" : "=r" (msr) :);
  28     return msr;
  29 }
  30
  31 static __inline__ void set_msr(unsigned long msr)
  32 {
  33     asm volatile("mtmsr %0" : : "r" (msr));
  34 }
  35
  36 /*
  37  * Definitions to access the CPM Timer registers
  38  * See 8xx_immap.h for Internal Memory Map layout,
  39  * and commproc.h for CPM Interrupt vectors (aka "IRQ"s)
  40  */
  41
  42 typedef struct tid_8xx_cpmtimer_s {
  43   int            cpm_vec;       /* CPM Interrupt Vector for this timer  */
  44   ushort        *tgcrp;         /* Pointer to Timer Global Config Reg.  */
  45   ushort        *tmrp;          /* Pointer to Timer Mode Register       */
  46   ushort        *trrp;          /* Pointer to Timer Reference Register  */
  47   ushort        *tcrp;          /* Pointer to Timer Capture Register    */
  48   ushort        *tcnp;          /* Pointer to Timer Counter Register    */
  49   ushort        *terp;          /* Pointer to Timer Event Register      */
  50 } tid_8xx_cpmtimer_t;
  51
  52 #ifndef CLOCKRATE
  53 #  define CLOCKRATE 64
  54 #endif
  55
  56 #define CPMT_CLOCK_DIV          16
  57 #define CPMT_MAX_PRESCALER      256
  58 #define CPMT_MAX_REFERENCE      65535   /* max. unsigned short */
  59
  60 #define CPMT_MAX_TICKS          (CPMT_MAX_REFERENCE * CPMT_MAX_PRESCALER)
  61 #define CPMT_MAX_TICKS_WITH_DIV (CPMT_MAX_REFERENCE * CPMT_MAX_PRESCALER * CPMT_CLOCK_DIV)
  62 #define CPMT_MAX_INTERVAL       (CPMT_MAX_TICKS_WITH_DIV / CLOCKRATE)
  63
  64 /* For now: always use max. prescaler value */
  65 #define CPMT_PRESCALER          (CPMT_MAX_PRESCALER)
  66
  67 /* CPM Timer Event Register Bits */
  68 #define CPMT_EVENT_CAP          0x0001  /* Capture Event                */
  69 #define CPMT_EVENT_REF          0x0002  /* Reference Counter Event      */
  70
  71 /* CPM Timer Global Config Register */
  72 #define CPMT_GCR_RST            0x0001  /* Reset  Timer                 */
  73 #define CPMT_GCR_STP            0x0002  /* Stop   Timer                 */
  74 #define CPMT_GCR_FRZ            0x0004  /* Freeze Timer                 */
  75 #define CPMT_GCR_GM_CAS         0x0008  /* Gate Mode / Cascade Timers   */
  76 #define CPMT_GCR_MASK           (CPMT_GCR_RST|CPMT_GCR_STP|CPMT_GCR_FRZ|CPMT_GCR_GM_CAS)
  77
  78 /* CPM Timer Mode register */
  79 #define CPMT_MR_GE              0x0001  /* Gate Enable                  */
  80 #define CPMT_MR_ICLK_CASC       0x0000  /* Clock internally cascaded    */
  81 #define CPMT_MR_ICLK_CLK        0x0002  /* Clock = system clock         */
  82 #define CPMT_MR_ICLK_CLKDIV     0x0004  /* Clock = system clock / 16    */
  83 #define CPMT_MR_ICLK_TIN        0x0006  /* Clock = TINx signal          */
  84 #define CPMT_MR_FRR             0x0008  /* Free Run / Restart           */
  85 #define CPMT_MR_ORI             0x0010  /* Out. Reference Interrupt En. */
  86 #define CPMT_MR_OM              0x0020  /* Output Mode                  */
  87 #define CPMT_MR_CE_DIS          0x0000  /* Capture/Interrupt disabled   */
  88 #define CPMT_MR_CE_RISE         0x0040  /* Capt./Interr. on rising  TIN */
  89 #define CPMT_MR_CE_FALL         0x0080  /* Capt./Interr. on falling TIN */
  90 #define CPMT_MR_CE_ANY          0x00C0  /* Capt./Interr. on any TIN edge*/
  91
  92
  93 /*
  94  * which CPM timer to use - index starts at 0 (= timer 1)
  95  */
  96 #define TID_TIMER_ID    0       /* use CPM timer 1              */
  97
  98 void setPeriod (tid_8xx_cpmtimer_t *hwp, ulong interval);
  99
 100 static const char usage[] = "\n[q, b, e, ?] ";
 101
 102 int timer (int argc, char * const argv[])
 103 {
 104         cpmtimer8xx_t *cpmtimerp;       /* Pointer to the CPM Timer structure   */
 105         tid_8xx_cpmtimer_t hw;
 106         tid_8xx_cpmtimer_t *hwp = &hw;
 107         int c;
 108         int running;
 109
 110         app_startup(argv);
 111
 112         /* Pointer to CPM Timer structure */
 113         cpmtimerp = &((immap_t *) gd->bd->bi_immr_base)->im_cpmtimer;
 114
 115         printf ("TIMERS=0x%x\n", (unsigned) cpmtimerp);
 116
 117         /* Initialize pointers depending on which timer we use */
 118         switch (TID_TIMER_ID) {
 119         case 0:
 120                 hwp->tmrp = &(cpmtimerp->cpmt_tmr1);
 121                 hwp->trrp = &(cpmtimerp->cpmt_trr1);
 122                 hwp->tcrp = &(cpmtimerp->cpmt_tcr1);
 123                 hwp->tcnp = &(cpmtimerp->cpmt_tcn1);
 124                 hwp->terp = &(cpmtimerp->cpmt_ter1);
 125                 hwp->cpm_vec = CPMVEC_TIMER1;
 126                 break;
 127         case 1:
 128                 hwp->tmrp = &(cpmtimerp->cpmt_tmr2);
 129                 hwp->trrp = &(cpmtimerp->cpmt_trr2);
 130                 hwp->tcrp = &(cpmtimerp->cpmt_tcr2);
 131                 hwp->tcnp = &(cpmtimerp->cpmt_tcn2);
 132                 hwp->terp = &(cpmtimerp->cpmt_ter2);
 133                 hwp->cpm_vec = CPMVEC_TIMER2;
 134                 break;
 135         case 2:
 136                 hwp->tmrp = &(cpmtimerp->cpmt_tmr3);
 137                 hwp->trrp = &(cpmtimerp->cpmt_trr3);
 138                 hwp->tcrp = &(cpmtimerp->cpmt_tcr3);
 139                 hwp->tcnp = &(cpmtimerp->cpmt_tcn3);
 140                 hwp->terp = &(cpmtimerp->cpmt_ter3);
 141                 hwp->cpm_vec = CPMVEC_TIMER3;
 142                 break;
 143         case 3:
 144                 hwp->tmrp = &(cpmtimerp->cpmt_tmr4);
 145                 hwp->trrp = &(cpmtimerp->cpmt_trr4);
 146                 hwp->tcrp = &(cpmtimerp->cpmt_tcr4);
 147                 hwp->tcnp = &(cpmtimerp->cpmt_tcn4);
 148                 hwp->terp = &(cpmtimerp->cpmt_ter4);
 149                 hwp->cpm_vec = CPMVEC_TIMER4;
 150                 break;
 151         }
 152
 153         hwp->tgcrp = &cpmtimerp->cpmt_tgcr;
 154
 155         printf ("Using timer %d\n"
 156                         "tgcr @ 0x%x, tmr @ 0x%x, trr @ 0x%x,"
 157                         " tcr @ 0x%x, tcn @ 0x%x, ter @ 0x%x\n",
 158                         TID_TIMER_ID + 1,
 159                         (unsigned) hwp->tgcrp,
 160                         (unsigned) hwp->tmrp,
 161                         (unsigned) hwp->trrp,
 162                         (unsigned) hwp->tcrp,
 163                         (unsigned) hwp->tcnp,
 164                         (unsigned) hwp->terp
 165                         );
 166
 167         /* reset timer    */
 168         *hwp->tgcrp &= ~(CPMT_GCR_MASK << TID_TIMER_ID);
 169
 170         /* clear all events */
 171         *hwp->terp = (CPMT_EVENT_CAP | CPMT_EVENT_REF);
 172
 173         puts(usage);
 174         running = 0;
 175         while ((c = getc()) != 'q') {
 176             if (c == 'b') {
 177
 178                 setPeriod (hwp, TIMER_PERIOD);  /* Set period and start ticking */
 179
 180                 /* Install interrupt handler (enable timer in CIMR) */
 181                 install_hdlr (hwp->cpm_vec, timer_handler, hwp);
 182
 183                 printf ("Enabling timer\n");
 184
 185                 /* enable timer */
 186                 *hwp->tgcrp |= (CPMT_GCR_RST << TID_TIMER_ID);
 187                 running = 1;
 188
 189 #ifdef  DEBUG
 190                 printf ("tgcr=0x%x, tmr=0x%x, trr=0x%x,"
 191                         " tcr=0x%x, tcn=0x%x, ter=0x%x\n",
 192                                 *hwp->tgcrp, *hwp->tmrp, *hwp->trrp,
 193                                 *hwp->tcrp,  *hwp->tcnp, *hwp->terp
 194                                 );
 195 #endif
 196             } else if (c == 'e') {
 197
 198                 printf ("Stopping timer\n");
 199
 200                 *hwp->tgcrp &= ~(CPMT_GCR_MASK << TID_TIMER_ID);
 201                 running = 0;
 202
 203 #ifdef  DEBUG
 204                 printf ("tgcr=0x%x, tmr=0x%x, trr=0x%x,"
 205                         " tcr=0x%x, tcn=0x%x, ter=0x%x\n",
 206                                 *hwp->tgcrp, *hwp->tmrp, *hwp->trrp,
 207                                 *hwp->tcrp,  *hwp->tcnp, *hwp->terp
 208                         );
 209 #endif
 210                 /* Uninstall interrupt handler */
 211                 free_hdlr (hwp->cpm_vec);
 212
 213             } else if (c == '?') {
 214 #ifdef  DEBUG
 215                 cpic8xx_t *cpm_icp = &((immap_t *) gd->bd->bi_immr_base)->im_cpic;
 216                 sysconf8xx_t *siup = &((immap_t *) gd->bd->bi_immr_base)->im_siu_conf;
 217 #endif
 218
 219                 printf ("\ntgcr=0x%x, tmr=0x%x, trr=0x%x,"
 220                         " tcr=0x%x, tcn=0x%x, ter=0x%x\n",
 221                                 *hwp->tgcrp, *hwp->tmrp, *hwp->trrp,
 222                                 *hwp->tcrp,  *hwp->tcnp, *hwp->terp
 223                         );
 224 #ifdef  DEBUG
 225                 printf ("SIUMCR=0x%08lx, SYPCR=0x%08lx,"
 226                         " SIMASK=0x%08lx, SIPEND=0x%08lx\n",
 227                                 siup->sc_siumcr,
 228                                 siup->sc_sypcr,
 229                                 siup->sc_simask,
 230                                 siup->sc_sipend
 231                         );
 232
 233                 printf ("CIMR=0x%08lx, CICR=0x%08lx, CIPR=0x%08lx\n",
 234                         cpm_icp->cpic_cimr,
 235                         cpm_icp->cpic_cicr,
 236                         cpm_icp->cpic_cipr
 237                         );
 238 #endif
 239             } else {
 240                 printf ("\nEnter: q - quit, b - start timer, e - stop timer, ? - get status\n");
 241             }
 242             puts(usage);
 243         }
 244         if (running) {
 245                 printf ("Stopping timer\n");
 246                 *hwp->tgcrp &= ~(CPMT_GCR_MASK << TID_TIMER_ID);
 247                 free_hdlr (hwp->cpm_vec);
 248         }
 249
 250         return (0);
 251 }
 252
 253
 254 /* Set period in microseconds and start.
 255  * Truncate to maximum period if more than this is requested - but warn about it.
 256  */
 257
 258 void setPeriod (tid_8xx_cpmtimer_t *hwp, ulong interval)
 259 {
 260         unsigned short prescaler;
 261         unsigned long ticks;
 262
 263         printf ("Set interval %ld us\n", interval);
 264
 265         /* Warn if requesting longer period than possible */
 266         if (interval > CPMT_MAX_INTERVAL) {
 267                 printf ("Truncate interval %ld to maximum (%d)\n",
 268                                 interval, CPMT_MAX_INTERVAL);
 269                 interval = CPMT_MAX_INTERVAL;
 270         }
 271         /*
 272          * Check if we want to use clock divider:
 273          * Since the reference counter can be incremented only in integer steps,
 274          * we try to keep it as big as possible to allow the resulting period to be
 275          * as precise as possible.
 276          */
 277         /* prescaler, enable interrupt, restart after ref count is reached */
 278         prescaler = (ushort) ((CPMT_PRESCALER - 1) << 8) |
 279                         CPMT_MR_ORI |
 280                         CPMT_MR_FRR;
 281
 282         ticks = ((ulong) CLOCKRATE * interval);
 283
 284         if (ticks > CPMT_MAX_TICKS) {
 285                 ticks /= CPMT_CLOCK_DIV;
 286                 prescaler |= CPMT_MR_ICLK_CLKDIV;       /* use system clock divided by 16 */
 287         } else {
 288                 prescaler |= CPMT_MR_ICLK_CLK;  /* use system clock without divider */
 289         }
 290
 291 #ifdef  DEBUG
 292         printf ("clock/%d, prescale factor %d, reference %ld, ticks %ld\n",
 293                         (ticks > CPMT_MAX_TICKS) ? CPMT_CLOCK_DIV : 1,
 294                         CPMT_PRESCALER,
 295                         (ticks / CPMT_PRESCALER),
 296                         ticks
 297                         );
 298 #endif
 299
 300         /* set prescaler register */
 301         *hwp->tmrp = prescaler;
 302
 303         /* clear timer counter */
 304         *hwp->tcnp = 0;
 305
 306         /* set reference register */
 307         *hwp->trrp = (unsigned short) (ticks / CPMT_PRESCALER);
 308
 309 #ifdef  DEBUG
 310         printf ("tgcr=0x%x, tmr=0x%x, trr=0x%x,"
 311                 " tcr=0x%x, tcn=0x%x, ter=0x%x\n",
 312                         *hwp->tgcrp, *hwp->tmrp, *hwp->trrp,
 313                         *hwp->tcrp,  *hwp->tcnp, *hwp->terp
 314                 );
 315 #endif
 316 }
 317
 318 /*
 319  * Handler for CPMVEC_TIMER1 interrupt
 320  */
 321 static
 322 void timer_handler (void *arg)
 323 {
 324         tid_8xx_cpmtimer_t *hwp = (tid_8xx_cpmtimer_t *)arg;
 325
 326         /* printf ("** TER1=%04x ** ", *hwp->terp); */
 327
 328         /* just for demonstration */
 329         printf (".");
 330
 331         /* clear all possible events: Ref. and Cap. */
 332         *hwp->terp = (CPMT_EVENT_CAP | CPMT_EVENT_REF);
 333 }