hw/timer/imx_gpt.c

   1 /*
   2  * IMX GPT Timer
   3  *
   4  * Copyright (c) 2008 OK Labs
   5  * Copyright (c) 2011 NICTA Pty Ltd
   6  * Originally written by Hans Jiang
   7  * Updated by Peter Chubb
   8  * Updated by Jean-Christophe Dubois
   9  *
  10  * This code is licensed under GPL version 2 or later.  See
  11  * the COPYING file in the top-level directory.
  12  *
  13  */
  14
  15 #include "hw/hw.h"
  16 #include "qemu/bitops.h"
  17 #include "qemu/timer.h"
  18 #include "hw/ptimer.h"
  19 #include "hw/sysbus.h"
  20 #include "hw/arm/imx.h"
  21
  22 #define TYPE_IMX_GPT "imx.gpt"
  23
  24 /*
  25  * Define to 1 for debug messages
  26  */
  27 #define DEBUG_TIMER 0
  28 #if DEBUG_TIMER
  29
  30 static char const *imx_gpt_reg_name(uint32_t reg)
  31 {
  32     switch (reg) {
  33     case 0:
  34         return "CR";
  35     case 1:
  36         return "PR";
  37     case 2:
  38         return "SR";
  39     case 3:
  40         return "IR";
  41     case 4:
  42         return "OCR1";
  43     case 5:
  44         return "OCR2";
  45     case 6:
  46         return "OCR3";
  47     case 7:
  48         return "ICR1";
  49     case 8:
  50         return "ICR2";
  51     case 9:
  52         return "CNT";
  53     default:
  54         return "[?]";
  55     }
  56 }
  57
  58 #  define DPRINTF(fmt, args...) \
  59           do { printf("%s: " fmt , __func__, ##args); } while (0)
  60 #else
  61 #  define DPRINTF(fmt, args...) do {} while (0)
  62 #endif
  63
  64 /*
  65  * Define to 1 for messages about attempts to
  66  * access unimplemented registers or similar.
  67  */
  68 #define DEBUG_IMPLEMENTATION 1
  69 #if DEBUG_IMPLEMENTATION
  70 #  define IPRINTF(fmt, args...) \
  71           do { fprintf(stderr, "%s: " fmt, __func__, ##args); } while (0)
  72 #else
  73 #  define IPRINTF(fmt, args...) do {} while (0)
  74 #endif
  75
  76 #define IMX_GPT(obj) \
  77         OBJECT_CHECK(IMXGPTState, (obj), TYPE_IMX_GPT)
  78 /*
  79  * GPT : General purpose timer
  80  *
  81  * This timer counts up continuously while it is enabled, resetting itself
  82  * to 0 when it reaches TIMER_MAX (in freerun mode) or when it
  83  * reaches the value of one of the ocrX (in periodic mode).
  84  */
  85
  86 #define TIMER_MAX  0XFFFFFFFFUL
  87
  88 /* Control register.  Not all of these bits have any effect (yet) */
  89 #define GPT_CR_EN     (1 << 0)  /* GPT Enable */
  90 #define GPT_CR_ENMOD  (1 << 1)  /* GPT Enable Mode */
  91 #define GPT_CR_DBGEN  (1 << 2)  /* GPT Debug mode enable */
  92 #define GPT_CR_WAITEN (1 << 3)  /* GPT Wait Mode Enable  */
  93 #define GPT_CR_DOZEN  (1 << 4)  /* GPT Doze mode enable */
  94 #define GPT_CR_STOPEN (1 << 5)  /* GPT Stop Mode Enable */
  95 #define GPT_CR_CLKSRC_SHIFT (6)
  96 #define GPT_CR_CLKSRC_MASK  (0x7)
  97
  98 #define GPT_CR_FRR    (1 << 9)  /* Freerun or Restart */
  99 #define GPT_CR_SWR    (1 << 15) /* Software Reset */
 100 #define GPT_CR_IM1    (3 << 16) /* Input capture channel 1 mode (2 bits) */
 101 #define GPT_CR_IM2    (3 << 18) /* Input capture channel 2 mode (2 bits) */
 102 #define GPT_CR_OM1    (7 << 20) /* Output Compare Channel 1 Mode (3 bits) */
 103 #define GPT_CR_OM2    (7 << 23) /* Output Compare Channel 2 Mode (3 bits) */
 104 #define GPT_CR_OM3    (7 << 26) /* Output Compare Channel 3 Mode (3 bits) */
 105 #define GPT_CR_FO1    (1 << 29) /* Force Output Compare Channel 1 */
 106 #define GPT_CR_FO2    (1 << 30) /* Force Output Compare Channel 2 */
 107 #define GPT_CR_FO3    (1 << 31) /* Force Output Compare Channel 3 */
 108
 109 #define GPT_SR_OF1  (1 << 0)
 110 #define GPT_SR_OF2  (1 << 1)
 111 #define GPT_SR_OF3  (1 << 2)
 112 #define GPT_SR_ROV  (1 << 5)
 113
 114 #define GPT_IR_OF1IE  (1 << 0)
 115 #define GPT_IR_OF2IE  (1 << 1)
 116 #define GPT_IR_OF3IE  (1 << 2)
 117 #define GPT_IR_ROVIE  (1 << 5)
 118
 119 typedef struct {
 120     SysBusDevice busdev;
 121     ptimer_state *timer;
 122     MemoryRegion iomem;
 123     DeviceState *ccm;
 124
 125     uint32_t cr;
 126     uint32_t pr;
 127     uint32_t sr;
 128     uint32_t ir;
 129     uint32_t ocr1;
 130     uint32_t ocr2;
 131     uint32_t ocr3;
 132     uint32_t icr1;
 133     uint32_t icr2;
 134     uint32_t cnt;
 135
 136     uint32_t next_timeout;
 137     uint32_t next_int;
 138
 139     uint32_t freq;
 140
 141     qemu_irq irq;
 142 } IMXGPTState;
 143
 144 static const VMStateDescription vmstate_imx_timer_gpt = {
 145     .name = "imx.gpt",
 146     .version_id = 3,
 147     .minimum_version_id = 3,
 148     .minimum_version_id_old = 3,
 149     .fields      = (VMStateField[]) {
 150         VMSTATE_UINT32(cr, IMXGPTState),
 151         VMSTATE_UINT32(pr, IMXGPTState),
 152         VMSTATE_UINT32(sr, IMXGPTState),
 153         VMSTATE_UINT32(ir, IMXGPTState),
 154         VMSTATE_UINT32(ocr1, IMXGPTState),
 155         VMSTATE_UINT32(ocr2, IMXGPTState),
 156         VMSTATE_UINT32(ocr3, IMXGPTState),
 157         VMSTATE_UINT32(icr1, IMXGPTState),
 158         VMSTATE_UINT32(icr2, IMXGPTState),
 159         VMSTATE_UINT32(cnt, IMXGPTState),
 160         VMSTATE_UINT32(next_timeout, IMXGPTState),
 161         VMSTATE_UINT32(next_int, IMXGPTState),
 162         VMSTATE_UINT32(freq, IMXGPTState),
 163         VMSTATE_PTIMER(timer, IMXGPTState),
 164         VMSTATE_END_OF_LIST()
 165     }
 166 };
 167
 168 static const IMXClk imx_gpt_clocks[] = {
 169     NOCLK,    /* 000 No clock source */
 170     IPG,      /* 001 ipg_clk, 532MHz*/
 171     IPG,      /* 010 ipg_clk_highfreq */
 172     NOCLK,    /* 011 not defined */
 173     CLK_32k,  /* 100 ipg_clk_32k */
 174     NOCLK,    /* 101 not defined */
 175     NOCLK,    /* 110 not defined */
 176     NOCLK,    /* 111 not defined */
 177 };
 178
 179 static void imx_gpt_set_freq(IMXGPTState *s)
 180 {
 181     uint32_t clksrc = extract32(s->cr, GPT_CR_CLKSRC_SHIFT, 3);
 182     uint32_t freq = imx_clock_frequency(s->ccm, imx_gpt_clocks[clksrc])
 183                                                 / (1 + s->pr);
 184     s->freq = freq;
 185
 186     DPRINTF("Setting clksrc %d to frequency %d\n", clksrc, freq);
 187
 188     if (freq) {
 189         ptimer_set_freq(s->timer, freq);
 190     }
 191 }
 192
 193 static void imx_gpt_update_int(IMXGPTState *s)
 194 {
 195     if ((s->sr & s->ir) && (s->cr & GPT_CR_EN)) {
 196         qemu_irq_raise(s->irq);
 197     } else {
 198         qemu_irq_lower(s->irq);
 199     }
 200 }
 201
 202 static uint32_t imx_gpt_update_count(IMXGPTState *s)
 203 {
 204     s->cnt = s->next_timeout - (uint32_t)ptimer_get_count(s->timer);
 205
 206     return s->cnt;
 207 }
 208
 209 static inline uint32_t imx_gpt_find_limit(uint32_t count, uint32_t reg,
 210                                              uint32_t timeout)
 211 {
 212     if ((count < reg) && (timeout > reg)) {
 213         timeout = reg;
 214     }
 215
 216     return timeout;
 217 }
 218
 219 static void imx_gpt_compute_next_timeout(IMXGPTState *s, bool event)
 220 {
 221     uint32_t timeout = TIMER_MAX;
 222     uint32_t count = 0;
 223     long long limit;
 224
 225     if (!(s->cr & GPT_CR_EN)) {
 226         /* if not enabled just return */
 227         return;
 228     }
 229
 230     if (event) {
 231         /* This is a timer event  */
 232
 233         if ((s->cr & GPT_CR_FRR)  && (s->next_timeout != TIMER_MAX)) {
 234             /*
 235              * if we are in free running mode and we have not reached
 236              * the TIMER_MAX limit, then update the count
 237              */
 238             count = imx_gpt_update_count(s);
 239         }
 240     } else {
 241         /* not a timer event, then just update the count */
 242
 243         count = imx_gpt_update_count(s);
 244     }
 245
 246     /* now, find the next timeout related to count */
 247
 248     if (s->ir & GPT_IR_OF1IE) {
 249         timeout = imx_gpt_find_limit(count, s->ocr1, timeout);
 250     }
 251     if (s->ir & GPT_IR_OF2IE) {
 252         timeout = imx_gpt_find_limit(count, s->ocr2, timeout);
 253     }
 254     if (s->ir & GPT_IR_OF3IE) {
 255         timeout = imx_gpt_find_limit(count, s->ocr3, timeout);
 256     }
 257
 258     /* find the next set of interrupts to raise for next timer event */
 259
 260     s->next_int = 0;
 261     if ((s->ir & GPT_IR_OF1IE) && (timeout == s->ocr1)) {
 262         s->next_int |= GPT_SR_OF1;
 263     }
 264     if ((s->ir & GPT_IR_OF2IE) && (timeout == s->ocr2)) {
 265         s->next_int |= GPT_SR_OF2;
 266     }
 267     if ((s->ir & GPT_IR_OF3IE) && (timeout == s->ocr3)) {
 268         s->next_int |= GPT_SR_OF3;
 269     }
 270     if ((s->ir & GPT_IR_ROVIE) && (timeout == TIMER_MAX)) {
 271         s->next_int |= GPT_SR_ROV;
 272     }
 273
 274     /* the new range to count down from */
 275     limit = timeout - imx_gpt_update_count(s);
 276
 277     if (limit < 0) {
 278         /*
 279          * if we reach here, then QEMU is running too slow and we pass the
 280          * timeout limit while computing it. Let's deliver the interrupt
 281          * and compute a new limit.
 282          */
 283         s->sr |= s->next_int;
 284
 285         imx_gpt_compute_next_timeout(s, event);
 286
 287         imx_gpt_update_int(s);
 288     } else {
 289         /* New timeout value */
 290         s->next_timeout = timeout;
 291
 292         /* reset the limit to the computed range */
 293         ptimer_set_limit(s->timer, limit, 1);
 294     }
 295 }
 296
 297 static uint64_t imx_gpt_read(void *opaque, hwaddr offset, unsigned size)
 298 {
 299     IMXGPTState *s = IMX_GPT(opaque);
 300     uint32_t reg_value = 0;
 301     uint32_t reg = offset >> 2;
 302
 303     switch (reg) {
 304     case 0: /* Control Register */
 305         reg_value = s->cr;
 306         break;
 307
 308     case 1: /* prescaler */
 309         reg_value = s->pr;
 310         break;
 311
 312     case 2: /* Status Register */
 313         reg_value = s->sr;
 314         break;
 315
 316     case 3: /* Interrupt Register */
 317         reg_value = s->ir;
 318         break;
 319
 320     case 4: /* Output Compare Register 1 */
 321         reg_value = s->ocr1;
 322         break;
 323
 324     case 5: /* Output Compare Register 2 */
 325         reg_value = s->ocr2;
 326         break;
 327
 328     case 6: /* Output Compare Register 3 */
 329         reg_value = s->ocr3;
 330         break;
 331
 332     case 7: /* input Capture Register 1 */
 333         qemu_log_mask(LOG_UNIMP, "icr1 feature is not implemented\n");
 334         reg_value = s->icr1;
 335         break;
 336
 337     case 8: /* input Capture Register 2 */
 338         qemu_log_mask(LOG_UNIMP, "icr2 feature is not implemented\n");
 339         reg_value = s->icr2;
 340         break;
 341
 342     case 9: /* cnt */
 343         imx_gpt_update_count(s);
 344         reg_value = s->cnt;
 345         break;
 346
 347     default:
 348         IPRINTF("Bad offset %x\n", reg);
 349         break;
 350     }
 351
 352     DPRINTF("(%s) = 0x%08x\n", imx_gpt_reg_name(reg), reg_value);
 353
 354     return reg_value;
 355 }
 356
 357 static void imx_gpt_reset(DeviceState *dev)
 358 {
 359     IMXGPTState *s = IMX_GPT(dev);
 360
 361     /* stop timer */
 362     ptimer_stop(s->timer);
 363
 364     /*
 365      * Soft reset doesn't touch some bits; hard reset clears them
 366      */
 367     s->cr &= ~(GPT_CR_EN|GPT_CR_ENMOD|GPT_CR_STOPEN|GPT_CR_DOZEN|
 368                GPT_CR_WAITEN|GPT_CR_DBGEN);
 369     s->sr = 0;
 370     s->pr = 0;
 371     s->ir = 0;
 372     s->cnt = 0;
 373     s->ocr1 = TIMER_MAX;
 374     s->ocr2 = TIMER_MAX;
 375     s->ocr3 = TIMER_MAX;
 376     s->icr1 = 0;
 377     s->icr2 = 0;
 378
 379     s->next_timeout = TIMER_MAX;
 380     s->next_int = 0;
 381
 382     /* compute new freq */
 383     imx_gpt_set_freq(s);
 384
 385     /* reset the limit to TIMER_MAX */
 386     ptimer_set_limit(s->timer, TIMER_MAX, 1);
 387
 388     /* if the timer is still enabled, restart it */
 389     if (s->freq && (s->cr & GPT_CR_EN)) {
 390         ptimer_run(s->timer, 1);
 391     }
 392 }
 393
 394 static void imx_gpt_write(void *opaque, hwaddr offset, uint64_t value,
 395                           unsigned size)
 396 {
 397     IMXGPTState *s = IMX_GPT(opaque);
 398     uint32_t oldreg;
 399     uint32_t reg = offset >> 2;
 400
 401     DPRINTF("(%s, value = 0x%08x)\n", imx_gpt_reg_name(reg),
 402             (uint32_t)value);
 403
 404     switch (reg) {
 405     case 0:
 406         oldreg = s->cr;
 407         s->cr = value & ~0x7c14;
 408         if (s->cr & GPT_CR_SWR) { /* force reset */
 409             /* handle the reset */
 410             imx_gpt_reset(DEVICE(s));
 411         } else {
 412             /* set our freq, as the source might have changed */
 413             imx_gpt_set_freq(s);
 414
 415             if ((oldreg ^ s->cr) & GPT_CR_EN) {
 416                 if (s->cr & GPT_CR_EN) {
 417                     if (s->cr & GPT_CR_ENMOD) {
 418                         s->next_timeout = TIMER_MAX;
 419                         ptimer_set_count(s->timer, TIMER_MAX);
 420                         imx_gpt_compute_next_timeout(s, false);
 421                     }
 422                     ptimer_run(s->timer, 1);
 423                 } else {
 424                     /* stop timer */
 425                     ptimer_stop(s->timer);
 426                 }
 427             }
 428         }
 429         break;
 430
 431     case 1: /* Prescaler */
 432         s->pr = value & 0xfff;
 433         imx_gpt_set_freq(s);
 434         break;
 435
 436     case 2: /* SR */
 437         s->sr &= ~(value & 0x3f);
 438         imx_gpt_update_int(s);
 439         break;
 440
 441     case 3: /* IR -- interrupt register */
 442         s->ir = value & 0x3f;
 443         imx_gpt_update_int(s);
 444
 445         imx_gpt_compute_next_timeout(s, false);
 446
 447         break;
 448
 449     case 4: /* OCR1 -- output compare register */
 450         s->ocr1 = value;
 451
 452         /* In non-freerun mode, reset count when this register is written */
 453         if (!(s->cr & GPT_CR_FRR)) {
 454             s->next_timeout = TIMER_MAX;
 455             ptimer_set_limit(s->timer, TIMER_MAX, 1);
 456         }
 457
 458         /* compute the new timeout */
 459         imx_gpt_compute_next_timeout(s, false);
 460
 461         break;
 462
 463     case 5: /* OCR2 -- output compare register */
 464         s->ocr2 = value;
 465
 466         /* compute the new timeout */
 467         imx_gpt_compute_next_timeout(s, false);
 468
 469         break;
 470
 471     case 6: /* OCR3 -- output compare register */
 472         s->ocr3 = value;
 473
 474         /* compute the new timeout */
 475         imx_gpt_compute_next_timeout(s, false);
 476
 477         break;
 478
 479     default:
 480         IPRINTF("Bad offset %x\n", reg);
 481         break;
 482     }
 483 }
 484
 485 static void imx_gpt_timeout(void *opaque)
 486 {
 487     IMXGPTState *s = IMX_GPT(opaque);
 488
 489     DPRINTF("\n");
 490
 491     s->sr |= s->next_int;
 492     s->next_int = 0;
 493
 494     imx_gpt_compute_next_timeout(s, true);
 495
 496     imx_gpt_update_int(s);
 497
 498     if (s->freq && (s->cr & GPT_CR_EN)) {
 499         ptimer_run(s->timer, 1);
 500     }
 501 }
 502
 503 static const MemoryRegionOps imx_gpt_ops = {
 504     .read = imx_gpt_read,
 505     .write = imx_gpt_write,
 506     .endianness = DEVICE_NATIVE_ENDIAN,
 507 };
 508
 509
 510 static void imx_gpt_realize(DeviceState *dev, Error **errp)
 511 {
 512     IMXGPTState *s = IMX_GPT(dev);
 513     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
 514     QEMUBH *bh;
 515
 516     sysbus_init_irq(sbd, &s->irq);
 517     memory_region_init_io(&s->iomem, OBJECT(s), &imx_gpt_ops, s, TYPE_IMX_GPT,
 518                           0x00001000);
 519     sysbus_init_mmio(sbd, &s->iomem);
 520
 521     bh = qemu_bh_new(imx_gpt_timeout, s);
 522     s->timer = ptimer_init(bh);
 523 }
 524
 525 void imx_timerg_create(const hwaddr addr, qemu_irq irq, DeviceState *ccm)
 526 {
 527     IMXGPTState *pp;
 528     DeviceState *dev;
 529
 530     dev = sysbus_create_simple(TYPE_IMX_GPT, addr, irq);
 531     pp = IMX_GPT(dev);
 532     pp->ccm = ccm;
 533 }
 534
 535 static void imx_gpt_class_init(ObjectClass *klass, void *data)
 536 {
 537     DeviceClass *dc = DEVICE_CLASS(klass);
 538
 539     dc->realize = imx_gpt_realize;
 540     dc->reset = imx_gpt_reset;
 541     dc->vmsd = &vmstate_imx_timer_gpt;
 542     dc->desc = "i.MX general timer";
 543 }
 544
 545 static const TypeInfo imx_gpt_info = {
 546     .name = TYPE_IMX_GPT,
 547     .parent = TYPE_SYS_BUS_DEVICE,
 548     .instance_size = sizeof(IMXGPTState),
 549     .class_init = imx_gpt_class_init,
 550 };
 551
 552 static void imx_gpt_register_types(void)
 553 {
 554     type_register_static(&imx_gpt_info);
 555 }
 556
 557 type_init(imx_gpt_register_types)