aboutsummaryrefslogtreecommitdiff
path: root/hw/timer/imx_gpt.c
blob: f2d1975e70a05da620554328f521a5222619245c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
/*
 * IMX GPT Timer
 *
 * Copyright (c) 2008 OK Labs
 * Copyright (c) 2011 NICTA Pty Ltd
 * Originally written by Hans Jiang
 * Updated by Peter Chubb
 * Updated by Jean-Christophe Dubois
 *
 * This code is licensed under GPL version 2 or later.  See
 * the COPYING file in the top-level directory.
 *
 */

#include "hw/hw.h"
#include "qemu/bitops.h"
#include "qemu/timer.h"
#include "hw/ptimer.h"
#include "hw/sysbus.h"
#include "hw/arm/imx.h"
#include "qemu/main-loop.h"

#define TYPE_IMX_GPT "imx.gpt"

/*
 * Define to 1 for debug messages
 */
#define DEBUG_TIMER 0
#if DEBUG_TIMER

static char const *imx_gpt_reg_name(uint32_t reg)
{
    switch (reg) {
    case 0:
        return "CR";
    case 1:
        return "PR";
    case 2:
        return "SR";
    case 3:
        return "IR";
    case 4:
        return "OCR1";
    case 5:
        return "OCR2";
    case 6:
        return "OCR3";
    case 7:
        return "ICR1";
    case 8:
        return "ICR2";
    case 9:
        return "CNT";
    default:
        return "[?]";
    }
}

#  define DPRINTF(fmt, args...) \
          do { printf("%s: " fmt , __func__, ##args); } while (0)
#else
#  define DPRINTF(fmt, args...) do {} while (0)
#endif

/*
 * Define to 1 for messages about attempts to
 * access unimplemented registers or similar.
 */
#define DEBUG_IMPLEMENTATION 1
#if DEBUG_IMPLEMENTATION
#  define IPRINTF(fmt, args...) \
          do { fprintf(stderr, "%s: " fmt, __func__, ##args); } while (0)
#else
#  define IPRINTF(fmt, args...) do {} while (0)
#endif

#define IMX_GPT(obj) \
        OBJECT_CHECK(IMXGPTState, (obj), TYPE_IMX_GPT)
/*
 * GPT : General purpose timer
 *
 * This timer counts up continuously while it is enabled, resetting itself
 * to 0 when it reaches TIMER_MAX (in freerun mode) or when it
 * reaches the value of one of the ocrX (in periodic mode).
 */

#define TIMER_MAX  0XFFFFFFFFUL

/* Control register.  Not all of these bits have any effect (yet) */
#define GPT_CR_EN     (1 << 0)  /* GPT Enable */
#define GPT_CR_ENMOD  (1 << 1)  /* GPT Enable Mode */
#define GPT_CR_DBGEN  (1 << 2)  /* GPT Debug mode enable */
#define GPT_CR_WAITEN (1 << 3)  /* GPT Wait Mode Enable  */
#define GPT_CR_DOZEN  (1 << 4)  /* GPT Doze mode enable */
#define GPT_CR_STOPEN (1 << 5)  /* GPT Stop Mode Enable */
#define GPT_CR_CLKSRC_SHIFT (6)
#define GPT_CR_CLKSRC_MASK  (0x7)

#define GPT_CR_FRR    (1 << 9)  /* Freerun or Restart */
#define GPT_CR_SWR    (1 << 15) /* Software Reset */
#define GPT_CR_IM1    (3 << 16) /* Input capture channel 1 mode (2 bits) */
#define GPT_CR_IM2    (3 << 18) /* Input capture channel 2 mode (2 bits) */
#define GPT_CR_OM1    (7 << 20) /* Output Compare Channel 1 Mode (3 bits) */
#define GPT_CR_OM2    (7 << 23) /* Output Compare Channel 2 Mode (3 bits) */
#define GPT_CR_OM3    (7 << 26) /* Output Compare Channel 3 Mode (3 bits) */
#define GPT_CR_FO1    (1 << 29) /* Force Output Compare Channel 1 */
#define GPT_CR_FO2    (1 << 30) /* Force Output Compare Channel 2 */
#define GPT_CR_FO3    (1 << 31) /* Force Output Compare Channel 3 */

#define GPT_SR_OF1  (1 << 0)
#define GPT_SR_OF2  (1 << 1)
#define GPT_SR_OF3  (1 << 2)
#define GPT_SR_ROV  (1 << 5)

#define GPT_IR_OF1IE  (1 << 0)
#define GPT_IR_OF2IE  (1 << 1)
#define GPT_IR_OF3IE  (1 << 2)
#define GPT_IR_ROVIE  (1 << 5)

typedef struct {
    SysBusDevice busdev;
    ptimer_state *timer;
    MemoryRegion iomem;
    DeviceState *ccm;

    uint32_t cr;
    uint32_t pr;
    uint32_t sr;
    uint32_t ir;
    uint32_t ocr1;
    uint32_t ocr2;
    uint32_t ocr3;
    uint32_t icr1;
    uint32_t icr2;
    uint32_t cnt;

    uint32_t next_timeout;
    uint32_t next_int;

    uint32_t freq;

    qemu_irq irq;
} IMXGPTState;

static const VMStateDescription vmstate_imx_timer_gpt = {
    .name = "imx.gpt",
    .version_id = 3,
    .minimum_version_id = 3,
    .minimum_version_id_old = 3,
    .fields      = (VMStateField[]) {
        VMSTATE_UINT32(cr, IMXGPTState),
        VMSTATE_UINT32(pr, IMXGPTState),
        VMSTATE_UINT32(sr, IMXGPTState),
        VMSTATE_UINT32(ir, IMXGPTState),
        VMSTATE_UINT32(ocr1, IMXGPTState),
        VMSTATE_UINT32(ocr2, IMXGPTState),
        VMSTATE_UINT32(ocr3, IMXGPTState),
        VMSTATE_UINT32(icr1, IMXGPTState),
        VMSTATE_UINT32(icr2, IMXGPTState),
        VMSTATE_UINT32(cnt, IMXGPTState),
        VMSTATE_UINT32(next_timeout, IMXGPTState),
        VMSTATE_UINT32(next_int, IMXGPTState),
        VMSTATE_UINT32(freq, IMXGPTState),
        VMSTATE_PTIMER(timer, IMXGPTState),
        VMSTATE_END_OF_LIST()
    }
};

static const IMXClk imx_gpt_clocks[] = {
    NOCLK,    /* 000 No clock source */
    IPG,      /* 001 ipg_clk, 532MHz*/
    IPG,      /* 010 ipg_clk_highfreq */
    NOCLK,    /* 011 not defined */
    CLK_32k,  /* 100 ipg_clk_32k */
    NOCLK,    /* 101 not defined */
    NOCLK,    /* 110 not defined */
    NOCLK,    /* 111 not defined */
};

static void imx_gpt_set_freq(IMXGPTState *s)
{
    uint32_t clksrc = extract32(s->cr, GPT_CR_CLKSRC_SHIFT, 3);
    uint32_t freq = imx_clock_frequency(s->ccm, imx_gpt_clocks[clksrc])
                                                / (1 + s->pr);
    s->freq = freq;

    DPRINTF("Setting clksrc %d to frequency %d\n", clksrc, freq);

    if (freq) {
        ptimer_set_freq(s->timer, freq);
    }
}

static void imx_gpt_update_int(IMXGPTState *s)
{
    if ((s->sr & s->ir) && (s->cr & GPT_CR_EN)) {
        qemu_irq_raise(s->irq);
    } else {
        qemu_irq_lower(s->irq);
    }
}

static uint32_t imx_gpt_update_count(IMXGPTState *s)
{
    s->cnt = s->next_timeout - (uint32_t)ptimer_get_count(s->timer);

    return s->cnt;
}

static inline uint32_t imx_gpt_find_limit(uint32_t count, uint32_t reg,
                                             uint32_t timeout)
{
    if ((count < reg) && (timeout > reg)) {
        timeout = reg;
    }

    return timeout;
}

static void imx_gpt_compute_next_timeout(IMXGPTState *s, bool event)
{
    uint32_t timeout = TIMER_MAX;
    uint32_t count = 0;
    long long limit;

    if (!(s->cr & GPT_CR_EN)) {
        /* if not enabled just return */
        return;
    }

    if (event) {
        /* This is a timer event  */

        if ((s->cr & GPT_CR_FRR)  && (s->next_timeout != TIMER_MAX)) {
            /*
             * if we are in free running mode and we have not reached
             * the TIMER_MAX limit, then update the count
             */
            count = imx_gpt_update_count(s);
        }
    } else {
        /* not a timer event, then just update the count */

        count = imx_gpt_update_count(s);
    }

    /* now, find the next timeout related to count */

    if (s->ir & GPT_IR_OF1IE) {
        timeout = imx_gpt_find_limit(count, s->ocr1, timeout);
    }
    if (s->ir & GPT_IR_OF2IE) {
        timeout = imx_gpt_find_limit(count, s->ocr2, timeout);
    }
    if (s->ir & GPT_IR_OF3IE) {
        timeout = imx_gpt_find_limit(count, s->ocr3, timeout);
    }

    /* find the next set of interrupts to raise for next timer event */

    s->next_int = 0;
    if ((s->ir & GPT_IR_OF1IE) && (timeout == s->ocr1)) {
        s->next_int |= GPT_SR_OF1;
    }
    if ((s->ir & GPT_IR_OF2IE) && (timeout == s->ocr2)) {
        s->next_int |= GPT_SR_OF2;
    }
    if ((s->ir & GPT_IR_OF3IE) && (timeout == s->ocr3)) {
        s->next_int |= GPT_SR_OF3;
    }
    if ((s->ir & GPT_IR_ROVIE) && (timeout == TIMER_MAX)) {
        s->next_int |= GPT_SR_ROV;
    }

    /* the new range to count down from */
    limit = timeout - imx_gpt_update_count(s);

    if (limit < 0) {
        /*
         * if we reach here, then QEMU is running too slow and we pass the
         * timeout limit while computing it. Let's deliver the interrupt
         * and compute a new limit.
         */
        s->sr |= s->next_int;

        imx_gpt_compute_next_timeout(s, event);

        imx_gpt_update_int(s);
    } else {
        /* New timeout value */
        s->next_timeout = timeout;

        /* reset the limit to the computed range */
        ptimer_set_limit(s->timer, limit, 1);
    }
}

static uint64_t imx_gpt_read(void *opaque, hwaddr offset, unsigned size)
{
    IMXGPTState *s = IMX_GPT(opaque);
    uint32_t reg_value = 0;
    uint32_t reg = offset >> 2;

    switch (reg) {
    case 0: /* Control Register */
        reg_value = s->cr;
        break;

    case 1: /* prescaler */
        reg_value = s->pr;
        break;

    case 2: /* Status Register */
        reg_value = s->sr;
        break;

    case 3: /* Interrupt Register */
        reg_value = s->ir;
        break;

    case 4: /* Output Compare Register 1 */
        reg_value = s->ocr1;
        break;

    case 5: /* Output Compare Register 2 */
        reg_value = s->ocr2;
        break;

    case 6: /* Output Compare Register 3 */
        reg_value = s->ocr3;
        break;

    case 7: /* input Capture Register 1 */
        qemu_log_mask(LOG_UNIMP, "icr1 feature is not implemented\n");
        reg_value = s->icr1;
        break;

    case 8: /* input Capture Register 2 */
        qemu_log_mask(LOG_UNIMP, "icr2 feature is not implemented\n");
        reg_value = s->icr2;
        break;

    case 9: /* cnt */
        imx_gpt_update_count(s);
        reg_value = s->cnt;
        break;

    default:
        IPRINTF("Bad offset %x\n", reg);
        break;
    }

    DPRINTF("(%s) = 0x%08x\n", imx_gpt_reg_name(reg), reg_value);

    return reg_value;
}

static void imx_gpt_reset(DeviceState *dev)
{
    IMXGPTState *s = IMX_GPT(dev);

    /* stop timer */
    ptimer_stop(s->timer);

    /*
     * Soft reset doesn't touch some bits; hard reset clears them
     */
    s->cr &= ~(GPT_CR_EN|GPT_CR_ENMOD|GPT_CR_STOPEN|GPT_CR_DOZEN|
               GPT_CR_WAITEN|GPT_CR_DBGEN);
    s->sr = 0;
    s->pr = 0;
    s->ir = 0;
    s->cnt = 0;
    s->ocr1 = TIMER_MAX;
    s->ocr2 = TIMER_MAX;
    s->ocr3 = TIMER_MAX;
    s->icr1 = 0;
    s->icr2 = 0;

    s->next_timeout = TIMER_MAX;
    s->next_int = 0;

    /* compute new freq */
    imx_gpt_set_freq(s);

    /* reset the limit to TIMER_MAX */
    ptimer_set_limit(s->timer, TIMER_MAX, 1);

    /* if the timer is still enabled, restart it */
    if (s->freq && (s->cr & GPT_CR_EN)) {
        ptimer_run(s->timer, 1);
    }
}

static void imx_gpt_write(void *opaque, hwaddr offset, uint64_t value,
                          unsigned size)
{
    IMXGPTState *s = IMX_GPT(opaque);
    uint32_t oldreg;
    uint32_t reg = offset >> 2;

    DPRINTF("(%s, value = 0x%08x)\n", imx_gpt_reg_name(reg),
            (uint32_t)value);

    switch (reg) {
    case 0:
        oldreg = s->cr;
        s->cr = value & ~0x7c14;
        if (s->cr & GPT_CR_SWR) { /* force reset */
            /* handle the reset */
            imx_gpt_reset(DEVICE(s));
        } else {
            /* set our freq, as the source might have changed */
            imx_gpt_set_freq(s);

            if ((oldreg ^ s->cr) & GPT_CR_EN) {
                if (s->cr & GPT_CR_EN) {
                    if (s->cr & GPT_CR_ENMOD) {
                        s->next_timeout = TIMER_MAX;
                        ptimer_set_count(s->timer, TIMER_MAX);
                        imx_gpt_compute_next_timeout(s, false);
                    }
                    ptimer_run(s->timer, 1);
                } else {
                    /* stop timer */
                    ptimer_stop(s->timer);
                }
            }
        }
        break;

    case 1: /* Prescaler */
        s->pr = value & 0xfff;
        imx_gpt_set_freq(s);
        break;

    case 2: /* SR */
        s->sr &= ~(value & 0x3f);
        imx_gpt_update_int(s);
        break;

    case 3: /* IR -- interrupt register */
        s->ir = value & 0x3f;
        imx_gpt_update_int(s);

        imx_gpt_compute_next_timeout(s, false);

        break;

    case 4: /* OCR1 -- output compare register */
        s->ocr1 = value;

        /* In non-freerun mode, reset count when this register is written */
        if (!(s->cr & GPT_CR_FRR)) {
            s->next_timeout = TIMER_MAX;
            ptimer_set_limit(s->timer, TIMER_MAX, 1);
        }

        /* compute the new timeout */
        imx_gpt_compute_next_timeout(s, false);

        break;

    case 5: /* OCR2 -- output compare register */
        s->ocr2 = value;

        /* compute the new timeout */
        imx_gpt_compute_next_timeout(s, false);

        break;

    case 6: /* OCR3 -- output compare register */
        s->ocr3 = value;

        /* compute the new timeout */
        imx_gpt_compute_next_timeout(s, false);

        break;

    default:
        IPRINTF("Bad offset %x\n", reg);
        break;
    }
}

static void imx_gpt_timeout(void *opaque)
{
    IMXGPTState *s = IMX_GPT(opaque);

    DPRINTF("\n");

    s->sr |= s->next_int;
    s->next_int = 0;

    imx_gpt_compute_next_timeout(s, true);

    imx_gpt_update_int(s);

    if (s->freq && (s->cr & GPT_CR_EN)) {
        ptimer_run(s->timer, 1);
    }
}

static const MemoryRegionOps imx_gpt_ops = {
    .read = imx_gpt_read,
    .write = imx_gpt_write,
    .endianness = DEVICE_NATIVE_ENDIAN,
};


static void imx_gpt_realize(DeviceState *dev, Error **errp)
{
    IMXGPTState *s = IMX_GPT(dev);
    SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
    QEMUBH *bh;

    sysbus_init_irq(sbd, &s->irq);
    memory_region_init_io(&s->iomem, OBJECT(s), &imx_gpt_ops, s, TYPE_IMX_GPT,
                          0x00001000);
    sysbus_init_mmio(sbd, &s->iomem);

    bh = qemu_bh_new(imx_gpt_timeout, s);
    s->timer = ptimer_init(bh);
}

void imx_timerg_create(const hwaddr addr, qemu_irq irq, DeviceState *ccm)
{
    IMXGPTState *pp;
    DeviceState *dev;

    dev = sysbus_create_simple(TYPE_IMX_GPT, addr, irq);
    pp = IMX_GPT(dev);
    pp->ccm = ccm;
}

static void imx_gpt_class_init(ObjectClass *klass, void *data)
{
    DeviceClass *dc = DEVICE_CLASS(klass);

    dc->realize = imx_gpt_realize;
    dc->reset = imx_gpt_reset;
    dc->vmsd = &vmstate_imx_timer_gpt;
    dc->desc = "i.MX general timer";
}

static const TypeInfo imx_gpt_info = {
    .name = TYPE_IMX_GPT,
    .parent = TYPE_SYS_BUS_DEVICE,
    .instance_size = sizeof(IMXGPTState),
    .class_init = imx_gpt_class_init,
};

static void imx_gpt_register_types(void)
{
    type_register_static(&imx_gpt_info);
}

type_init(imx_gpt_register_types)