hw/timer/grlib_gptimer.c

   1 /*
   2  * QEMU GRLIB GPTimer Emulator
   3  *
   4  * Copyright (c) 2010-2011 AdaCore
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24
  25 #include "qemu/osdep.h"
  26 #include "hw/sysbus.h"
  27 #include "qemu/timer.h"
  28 #include "hw/ptimer.h"
  29 #include "qemu/main-loop.h"
  30
  31 #include "trace.h"
  32
  33 #define UNIT_REG_SIZE    16     /* Size of memory mapped regs for the unit */
  34 #define GPTIMER_REG_SIZE 16     /* Size of memory mapped regs for a GPTimer */
  35
  36 #define GPTIMER_MAX_TIMERS 8
  37
  38 /* GPTimer Config register fields */
  39 #define GPTIMER_ENABLE      (1 << 0)
  40 #define GPTIMER_RESTART     (1 << 1)
  41 #define GPTIMER_LOAD        (1 << 2)
  42 #define GPTIMER_INT_ENABLE  (1 << 3)
  43 #define GPTIMER_INT_PENDING (1 << 4)
  44 #define GPTIMER_CHAIN       (1 << 5) /* Not supported */
  45 #define GPTIMER_DEBUG_HALT  (1 << 6) /* Not supported */
  46
  47 /* Memory mapped register offsets */
  48 #define SCALER_OFFSET         0x00
  49 #define SCALER_RELOAD_OFFSET  0x04
  50 #define CONFIG_OFFSET         0x08
  51 #define COUNTER_OFFSET        0x00
  52 #define COUNTER_RELOAD_OFFSET 0x04
  53 #define TIMER_BASE            0x10
  54
  55 #define TYPE_GRLIB_GPTIMER "grlib,gptimer"
  56 #define GRLIB_GPTIMER(obj) \
  57     OBJECT_CHECK(GPTimerUnit, (obj), TYPE_GRLIB_GPTIMER)
  58
  59 typedef struct GPTimer     GPTimer;
  60 typedef struct GPTimerUnit GPTimerUnit;
  61
  62 struct GPTimer {
  63     QEMUBH *bh;
  64     struct ptimer_state *ptimer;
  65
  66     qemu_irq     irq;
  67     int          id;
  68     GPTimerUnit *unit;
  69
  70     /* registers */
  71     uint32_t counter;
  72     uint32_t reload;
  73     uint32_t config;
  74 };
  75
  76 struct GPTimerUnit {
  77     SysBusDevice  parent_obj;
  78
  79     MemoryRegion iomem;
  80
  81     uint32_t nr_timers;         /* Number of timers available */
  82     uint32_t freq_hz;           /* System frequency */
  83     uint32_t irq_line;          /* Base irq line */
  84
  85     GPTimer *timers;
  86
  87     /* registers */
  88     uint32_t scaler;
  89     uint32_t reload;
  90     uint32_t config;
  91 };
  92
  93 static void grlib_gptimer_enable(GPTimer *timer)
  94 {
  95     assert(timer != NULL);
  96
  97
  98     ptimer_stop(timer->ptimer);
  99
 100     if (!(timer->config & GPTIMER_ENABLE)) {
 101         /* Timer disabled */
 102         trace_grlib_gptimer_disabled(timer->id, timer->config);
 103         return;
 104     }
 105
 106     /* ptimer is triggered when the counter reach 0 but GPTimer is triggered at
 107        underflow. Set count + 1 to simulate the GPTimer behavior. */
 108
 109     trace_grlib_gptimer_enable(timer->id, timer->counter);
 110
 111     ptimer_set_count(timer->ptimer, (uint64_t)timer->counter + 1);
 112     ptimer_run(timer->ptimer, 1);
 113 }
 114
 115 static void grlib_gptimer_restart(GPTimer *timer)
 116 {
 117     assert(timer != NULL);
 118
 119     trace_grlib_gptimer_restart(timer->id, timer->reload);
 120
 121     timer->counter = timer->reload;
 122     grlib_gptimer_enable(timer);
 123 }
 124
 125 static void grlib_gptimer_set_scaler(GPTimerUnit *unit, uint32_t scaler)
 126 {
 127     int i = 0;
 128     uint32_t value = 0;
 129
 130     assert(unit != NULL);
 131
 132     if (scaler > 0) {
 133         value = unit->freq_hz / (scaler + 1);
 134     } else {
 135         value = unit->freq_hz;
 136     }
 137
 138     trace_grlib_gptimer_set_scaler(scaler, value);
 139
 140     for (i = 0; i < unit->nr_timers; i++) {
 141         ptimer_set_freq(unit->timers[i].ptimer, value);
 142     }
 143 }
 144
 145 static void grlib_gptimer_hit(void *opaque)
 146 {
 147     GPTimer *timer = opaque;
 148     assert(timer != NULL);
 149
 150     trace_grlib_gptimer_hit(timer->id);
 151
 152     /* Timer expired */
 153
 154     if (timer->config & GPTIMER_INT_ENABLE) {
 155         /* Set the pending bit (only unset by write in the config register) */
 156         timer->config |= GPTIMER_INT_PENDING;
 157         qemu_irq_pulse(timer->irq);
 158     }
 159
 160     if (timer->config & GPTIMER_RESTART) {
 161         grlib_gptimer_restart(timer);
 162     }
 163 }
 164
 165 static uint64_t grlib_gptimer_read(void *opaque, hwaddr addr,
 166                                    unsigned size)
 167 {
 168     GPTimerUnit        *unit  = opaque;
 169     hwaddr  timer_addr;
 170     int                 id;
 171     uint32_t            value = 0;
 172
 173     addr &= 0xff;
 174
 175     /* Unit registers */
 176     switch (addr) {
 177     case SCALER_OFFSET:
 178         trace_grlib_gptimer_readl(-1, addr, unit->scaler);
 179         return unit->scaler;
 180
 181     case SCALER_RELOAD_OFFSET:
 182         trace_grlib_gptimer_readl(-1, addr, unit->reload);
 183         return unit->reload;
 184
 185     case CONFIG_OFFSET:
 186         trace_grlib_gptimer_readl(-1, addr, unit->config);
 187         return unit->config;
 188
 189     default:
 190         break;
 191     }
 192
 193     timer_addr = (addr % TIMER_BASE);
 194     id         = (addr - TIMER_BASE) / TIMER_BASE;
 195
 196     if (id >= 0 && id < unit->nr_timers) {
 197
 198         /* GPTimer registers */
 199         switch (timer_addr) {
 200         case COUNTER_OFFSET:
 201             value = ptimer_get_count(unit->timers[id].ptimer);
 202             trace_grlib_gptimer_readl(id, addr, value);
 203             return value;
 204
 205         case COUNTER_RELOAD_OFFSET:
 206             value = unit->timers[id].reload;
 207             trace_grlib_gptimer_readl(id, addr, value);
 208             return value;
 209
 210         case CONFIG_OFFSET:
 211             trace_grlib_gptimer_readl(id, addr, unit->timers[id].config);
 212             return unit->timers[id].config;
 213
 214         default:
 215             break;
 216         }
 217
 218     }
 219
 220     trace_grlib_gptimer_readl(-1, addr, 0);
 221     return 0;
 222 }
 223
 224 static void grlib_gptimer_write(void *opaque, hwaddr addr,
 225                                 uint64_t value, unsigned size)
 226 {
 227     GPTimerUnit        *unit = opaque;
 228     hwaddr  timer_addr;
 229     int                 id;
 230
 231     addr &= 0xff;
 232
 233     /* Unit registers */
 234     switch (addr) {
 235     case SCALER_OFFSET:
 236         value &= 0xFFFF; /* clean up the value */
 237         unit->scaler = value;
 238         trace_grlib_gptimer_writel(-1, addr, unit->scaler);
 239         return;
 240
 241     case SCALER_RELOAD_OFFSET:
 242         value &= 0xFFFF; /* clean up the value */
 243         unit->reload = value;
 244         trace_grlib_gptimer_writel(-1, addr, unit->reload);
 245         grlib_gptimer_set_scaler(unit, value);
 246         return;
 247
 248     case CONFIG_OFFSET:
 249         /* Read Only (disable timer freeze not supported) */
 250         trace_grlib_gptimer_writel(-1, addr, 0);
 251         return;
 252
 253     default:
 254         break;
 255     }
 256
 257     timer_addr = (addr % TIMER_BASE);
 258     id         = (addr - TIMER_BASE) / TIMER_BASE;
 259
 260     if (id >= 0 && id < unit->nr_timers) {
 261
 262         /* GPTimer registers */
 263         switch (timer_addr) {
 264         case COUNTER_OFFSET:
 265             trace_grlib_gptimer_writel(id, addr, value);
 266             unit->timers[id].counter = value;
 267             grlib_gptimer_enable(&unit->timers[id]);
 268             return;
 269
 270         case COUNTER_RELOAD_OFFSET:
 271             trace_grlib_gptimer_writel(id, addr, value);
 272             unit->timers[id].reload = value;
 273             return;
 274
 275         case CONFIG_OFFSET:
 276             trace_grlib_gptimer_writel(id, addr, value);
 277
 278             if (value & GPTIMER_INT_PENDING) {
 279                 /* clear pending bit */
 280                 value &= ~GPTIMER_INT_PENDING;
 281             } else {
 282                 /* keep pending bit */
 283                 value |= unit->timers[id].config & GPTIMER_INT_PENDING;
 284             }
 285
 286             unit->timers[id].config = value;
 287
 288             /* gptimer_restart calls gptimer_enable, so if "enable" and "load"
 289                bits are present, we just have to call restart. */
 290
 291             if (value & GPTIMER_LOAD) {
 292                 grlib_gptimer_restart(&unit->timers[id]);
 293             } else if (value & GPTIMER_ENABLE) {
 294                 grlib_gptimer_enable(&unit->timers[id]);
 295             }
 296
 297             /* These fields must always be read as 0 */
 298             value &= ~(GPTIMER_LOAD & GPTIMER_DEBUG_HALT);
 299
 300             unit->timers[id].config = value;
 301             return;
 302
 303         default:
 304             break;
 305         }
 306
 307     }
 308
 309     trace_grlib_gptimer_writel(-1, addr, value);
 310 }
 311
 312 static const MemoryRegionOps grlib_gptimer_ops = {
 313     .read = grlib_gptimer_read,
 314     .write = grlib_gptimer_write,
 315     .endianness = DEVICE_NATIVE_ENDIAN,
 316     .valid = {
 317         .min_access_size = 4,
 318         .max_access_size = 4,
 319     },
 320 };
 321
 322 static void grlib_gptimer_reset(DeviceState *d)
 323 {
 324     GPTimerUnit *unit = GRLIB_GPTIMER(d);
 325     int          i    = 0;
 326
 327     assert(unit != NULL);
 328
 329     unit->scaler = 0;
 330     unit->reload = 0;
 331
 332     unit->config  = unit->nr_timers;
 333     unit->config |= unit->irq_line << 3;
 334     unit->config |= 1 << 8;     /* separate interrupt */
 335     unit->config |= 1 << 9;     /* Disable timer freeze */
 336
 337
 338     for (i = 0; i < unit->nr_timers; i++) {
 339         GPTimer *timer = &unit->timers[i];
 340
 341         timer->counter = 0;
 342         timer->reload = 0;
 343         timer->config = 0;
 344         ptimer_stop(timer->ptimer);
 345         ptimer_set_count(timer->ptimer, 0);
 346         ptimer_set_freq(timer->ptimer, unit->freq_hz);
 347     }
 348 }
 349
 350 static int grlib_gptimer_init(SysBusDevice *dev)
 351 {
 352     GPTimerUnit  *unit = GRLIB_GPTIMER(dev);
 353     unsigned int  i;
 354
 355     assert(unit->nr_timers > 0);
 356     assert(unit->nr_timers <= GPTIMER_MAX_TIMERS);
 357
 358     unit->timers = g_malloc0(sizeof unit->timers[0] * unit->nr_timers);
 359
 360     for (i = 0; i < unit->nr_timers; i++) {
 361         GPTimer *timer = &unit->timers[i];
 362
 363         timer->unit   = unit;
 364         timer->bh     = qemu_bh_new(grlib_gptimer_hit, timer);
 365         timer->ptimer = ptimer_init(timer->bh, PTIMER_POLICY_DEFAULT);
 366         timer->id     = i;
 367
 368         /* One IRQ line for each timer */
 369         sysbus_init_irq(dev, &timer->irq);
 370
 371         ptimer_set_freq(timer->ptimer, unit->freq_hz);
 372     }
 373
 374     memory_region_init_io(&unit->iomem, OBJECT(unit), &grlib_gptimer_ops,
 375                           unit, "gptimer",
 376                           UNIT_REG_SIZE + GPTIMER_REG_SIZE * unit->nr_timers);
 377
 378     sysbus_init_mmio(dev, &unit->iomem);
 379     return 0;
 380 }
 381
 382 static Property grlib_gptimer_properties[] = {
 383     DEFINE_PROP_UINT32("frequency", GPTimerUnit, freq_hz,   40000000),
 384     DEFINE_PROP_UINT32("irq-line",  GPTimerUnit, irq_line,  8),
 385     DEFINE_PROP_UINT32("nr-timers", GPTimerUnit, nr_timers, 2),
 386     DEFINE_PROP_END_OF_LIST(),
 387 };
 388
 389 static void grlib_gptimer_class_init(ObjectClass *klass, void *data)
 390 {
 391     DeviceClass *dc = DEVICE_CLASS(klass);
 392     SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
 393
 394     k->init = grlib_gptimer_init;
 395     dc->reset = grlib_gptimer_reset;
 396     dc->props = grlib_gptimer_properties;
 397 }
 398
 399 static const TypeInfo grlib_gptimer_info = {
 400     .name          = TYPE_GRLIB_GPTIMER,
 401     .parent        = TYPE_SYS_BUS_DEVICE,
 402     .instance_size = sizeof(GPTimerUnit),
 403     .class_init    = grlib_gptimer_class_init,
 404 };
 405
 406 static void grlib_gptimer_register_types(void)
 407 {
 408     type_register_static(&grlib_gptimer_info);
 409 }
 410
 411 type_init(grlib_gptimer_register_types)