hw/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 "sysbus.h"
  26 #include "qemu-timer.h"
  27
  28 #include "trace.h"
  29
  30 #define UNIT_REG_SIZE    16     /* Size of memory mapped regs for the unit */
  31 #define GPTIMER_REG_SIZE 16     /* Size of memory mapped regs for a GPTimer */
  32
  33 #define GPTIMER_MAX_TIMERS 8
  34
  35 /* GPTimer Config register fields */
  36 #define GPTIMER_ENABLE      (1 << 0)
  37 #define GPTIMER_RESTART     (1 << 1)
  38 #define GPTIMER_LOAD        (1 << 2)
  39 #define GPTIMER_INT_ENABLE  (1 << 3)
  40 #define GPTIMER_INT_PENDING (1 << 4)
  41 #define GPTIMER_CHAIN       (1 << 5) /* Not supported */
  42 #define GPTIMER_DEBUG_HALT  (1 << 6) /* Not supported */
  43
  44 /* Memory mapped register offsets */
  45 #define SCALER_OFFSET         0x00
  46 #define SCALER_RELOAD_OFFSET  0x04
  47 #define CONFIG_OFFSET         0x08
  48 #define COUNTER_OFFSET        0x00
  49 #define COUNTER_RELOAD_OFFSET 0x04
  50 #define TIMER_BASE            0x10
  51
  52 typedef struct GPTimer     GPTimer;
  53 typedef struct GPTimerUnit GPTimerUnit;
  54
  55 struct GPTimer {
  56     QEMUBH *bh;
  57     struct ptimer_state *ptimer;
  58
  59     qemu_irq     irq;
  60     int          id;
  61     GPTimerUnit *unit;
  62
  63     /* registers */
  64     uint32_t counter;
  65     uint32_t reload;
  66     uint32_t config;
  67 };
  68
  69 struct GPTimerUnit {
  70     SysBusDevice  busdev;
  71
  72     uint32_t nr_timers;         /* Number of timers available */
  73     uint32_t freq_hz;           /* System frequency */
  74     uint32_t irq_line;          /* Base irq line */
  75
  76     GPTimer *timers;
  77
  78     /* registers */
  79     uint32_t scaler;
  80     uint32_t reload;
  81     uint32_t config;
  82 };
  83
  84 static void grlib_gptimer_enable(GPTimer *timer)
  85 {
  86     assert(timer != NULL);
  87
  88
  89     ptimer_stop(timer->ptimer);
  90
  91     if (!(timer->config & GPTIMER_ENABLE)) {
  92         /* Timer disabled */
  93         trace_grlib_gptimer_disabled(timer->id, timer->config);
  94         return;
  95     }
  96
  97     /* ptimer is triggered when the counter reach 0 but GPTimer is triggered at
  98        underflow. Set count + 1 to simulate the GPTimer behavior. */
  99
 100     trace_grlib_gptimer_enable(timer->id, timer->counter + 1);
 101
 102     ptimer_set_count(timer->ptimer, timer->counter + 1);
 103     ptimer_run(timer->ptimer, 1);
 104 }
 105
 106 static void grlib_gptimer_restart(GPTimer *timer)
 107 {
 108     assert(timer != NULL);
 109
 110     trace_grlib_gptimer_restart(timer->id, timer->reload);
 111
 112     timer->counter = timer->reload;
 113     grlib_gptimer_enable(timer);
 114 }
 115
 116 static void grlib_gptimer_set_scaler(GPTimerUnit *unit, uint32_t scaler)
 117 {
 118     int i = 0;
 119     uint32_t value = 0;
 120
 121     assert(unit != NULL);
 122
 123     if (scaler > 0) {
 124         value = unit->freq_hz / (scaler + 1);
 125     } else {
 126         value = unit->freq_hz;
 127     }
 128
 129     trace_grlib_gptimer_set_scaler(scaler, value);
 130
 131     for (i = 0; i < unit->nr_timers; i++) {
 132         ptimer_set_freq(unit->timers[i].ptimer, value);
 133     }
 134 }
 135
 136 static void grlib_gptimer_hit(void *opaque)
 137 {
 138     GPTimer *timer = opaque;
 139     assert(timer != NULL);
 140
 141     trace_grlib_gptimer_hit(timer->id);
 142
 143     /* Timer expired */
 144
 145     if (timer->config & GPTIMER_INT_ENABLE) {
 146         /* Set the pending bit (only unset by write in the config register) */
 147         timer->config |= GPTIMER_INT_PENDING;
 148         qemu_irq_pulse(timer->irq);
 149     }
 150
 151     if (timer->config & GPTIMER_RESTART) {
 152         grlib_gptimer_restart(timer);
 153     }
 154 }
 155
 156 static uint32_t grlib_gptimer_readl(void *opaque, target_phys_addr_t addr)
 157 {
 158     GPTimerUnit        *unit  = opaque;
 159     target_phys_addr_t  timer_addr;
 160     int                 id;
 161     uint32_t            value = 0;
 162
 163     addr &= 0xff;
 164
 165     /* Unit registers */
 166     switch (addr) {
 167     case SCALER_OFFSET:
 168         trace_grlib_gptimer_readl(-1, addr, unit->scaler);
 169         return unit->scaler;
 170
 171     case SCALER_RELOAD_OFFSET:
 172         trace_grlib_gptimer_readl(-1, addr, unit->reload);
 173         return unit->reload;
 174
 175     case CONFIG_OFFSET:
 176         trace_grlib_gptimer_readl(-1, addr, unit->config);
 177         return unit->config;
 178
 179     default:
 180         break;
 181     }
 182
 183     timer_addr = (addr % TIMER_BASE);
 184     id         = (addr - TIMER_BASE) / TIMER_BASE;
 185
 186     if (id >= 0 && id < unit->nr_timers) {
 187
 188         /* GPTimer registers */
 189         switch (timer_addr) {
 190         case COUNTER_OFFSET:
 191             value = ptimer_get_count(unit->timers[id].ptimer);
 192             trace_grlib_gptimer_readl(id, addr, value);
 193             return value;
 194
 195         case COUNTER_RELOAD_OFFSET:
 196             value = unit->timers[id].reload;
 197             trace_grlib_gptimer_readl(id, addr, value);
 198             return value;
 199
 200         case CONFIG_OFFSET:
 201             trace_grlib_gptimer_readl(id, addr, unit->timers[id].config);
 202             return unit->timers[id].config;
 203
 204         default:
 205             break;
 206         }
 207
 208     }
 209
 210     trace_grlib_gptimer_readl(-1, addr, 0);
 211     return 0;
 212 }
 213
 214 static void
 215 grlib_gptimer_writel(void *opaque, target_phys_addr_t addr, uint32_t value)
 216 {
 217     GPTimerUnit        *unit = opaque;
 218     target_phys_addr_t  timer_addr;
 219     int                 id;
 220
 221     addr &= 0xff;
 222
 223     /* Unit registers */
 224     switch (addr) {
 225     case SCALER_OFFSET:
 226         value &= 0xFFFF; /* clean up the value */
 227         unit->scaler = value;
 228         trace_grlib_gptimer_writel(-1, addr, unit->scaler);
 229         return;
 230
 231     case SCALER_RELOAD_OFFSET:
 232         value &= 0xFFFF; /* clean up the value */
 233         unit->reload = value;
 234         trace_grlib_gptimer_writel(-1, addr, unit->reload);
 235         grlib_gptimer_set_scaler(unit, value);
 236         return;
 237
 238     case CONFIG_OFFSET:
 239         /* Read Only (disable timer freeze not supported) */
 240         trace_grlib_gptimer_writel(-1, addr, 0);
 241         return;
 242
 243     default:
 244         break;
 245     }
 246
 247     timer_addr = (addr % TIMER_BASE);
 248     id         = (addr - TIMER_BASE) / TIMER_BASE;
 249
 250     if (id >= 0 && id < unit->nr_timers) {
 251
 252         /* GPTimer registers */
 253         switch (timer_addr) {
 254         case COUNTER_OFFSET:
 255             trace_grlib_gptimer_writel(id, addr, value);
 256             unit->timers[id].counter = value;
 257             grlib_gptimer_enable(&unit->timers[id]);
 258             return;
 259
 260         case COUNTER_RELOAD_OFFSET:
 261             trace_grlib_gptimer_writel(id, addr, value);
 262             unit->timers[id].reload = value;
 263             return;
 264
 265         case CONFIG_OFFSET:
 266             trace_grlib_gptimer_writel(id, addr, value);
 267
 268             if (value & GPTIMER_INT_PENDING) {
 269                 /* clear pending bit */
 270                 value &= ~GPTIMER_INT_PENDING;
 271             } else {
 272                 /* keep pending bit */
 273                 value |= unit->timers[id].config & GPTIMER_INT_PENDING;
 274             }
 275
 276             unit->timers[id].config = value;
 277
 278             /* gptimer_restart calls gptimer_enable, so if "enable" and "load"
 279                bits are present, we just have to call restart. */
 280
 281             if (value & GPTIMER_LOAD) {
 282                 grlib_gptimer_restart(&unit->timers[id]);
 283             } else if (value & GPTIMER_ENABLE) {
 284                 grlib_gptimer_enable(&unit->timers[id]);
 285             }
 286
 287             /* These fields must always be read as 0 */
 288             value &= ~(GPTIMER_LOAD & GPTIMER_DEBUG_HALT);
 289
 290             unit->timers[id].config = value;
 291             return;
 292
 293         default:
 294             break;
 295         }
 296
 297     }
 298
 299     trace_grlib_gptimer_writel(-1, addr, value);
 300 }
 301
 302 static CPUReadMemoryFunc * const grlib_gptimer_read[] = {
 303     NULL, NULL, grlib_gptimer_readl,
 304 };
 305
 306 static CPUWriteMemoryFunc * const grlib_gptimer_write[] = {
 307     NULL, NULL, grlib_gptimer_writel,
 308 };
 309
 310 static void grlib_gptimer_reset(DeviceState *d)
 311 {
 312     GPTimerUnit *unit = container_of(d, GPTimerUnit, busdev.qdev);
 313     int          i    = 0;
 314
 315     assert(unit != NULL);
 316
 317     unit->scaler = 0;
 318     unit->reload = 0;
 319     unit->config = 0;
 320
 321     unit->config  = unit->nr_timers;
 322     unit->config |= unit->irq_line << 3;
 323     unit->config |= 1 << 8;     /* separate interrupt */
 324     unit->config |= 1 << 9;     /* Disable timer freeze */
 325
 326
 327     for (i = 0; i < unit->nr_timers; i++) {
 328         GPTimer *timer = &unit->timers[i];
 329
 330         timer->counter = 0;
 331         timer->reload = 0;
 332         timer->config = 0;
 333         ptimer_stop(timer->ptimer);
 334         ptimer_set_count(timer->ptimer, 0);
 335         ptimer_set_freq(timer->ptimer, unit->freq_hz);
 336     }
 337 }
 338
 339 static int grlib_gptimer_init(SysBusDevice *dev)
 340 {
 341     GPTimerUnit  *unit = FROM_SYSBUS(typeof(*unit), dev);
 342     unsigned int  i;
 343     int           timer_regs;
 344
 345     assert(unit->nr_timers > 0);
 346     assert(unit->nr_timers <= GPTIMER_MAX_TIMERS);
 347
 348     unit->timers = qemu_mallocz(sizeof unit->timers[0] * unit->nr_timers);
 349
 350     for (i = 0; i < unit->nr_timers; i++) {
 351         GPTimer *timer = &unit->timers[i];
 352
 353         timer->unit   = unit;
 354         timer->bh     = qemu_bh_new(grlib_gptimer_hit, timer);
 355         timer->ptimer = ptimer_init(timer->bh);
 356         timer->id     = i;
 357
 358         /* One IRQ line for each timer */
 359         sysbus_init_irq(dev, &timer->irq);
 360
 361         ptimer_set_freq(timer->ptimer, unit->freq_hz);
 362     }
 363
 364     timer_regs = cpu_register_io_memory(grlib_gptimer_read,
 365                                         grlib_gptimer_write,
 366                                         unit, DEVICE_NATIVE_ENDIAN);
 367     if (timer_regs < 0) {
 368         return -1;
 369     }
 370
 371     sysbus_init_mmio(dev, UNIT_REG_SIZE + GPTIMER_REG_SIZE * unit->nr_timers,
 372                      timer_regs);
 373     return 0;
 374 }
 375
 376 static SysBusDeviceInfo grlib_gptimer_info = {
 377     .init       = grlib_gptimer_init,
 378     .qdev.name  = "grlib,gptimer",
 379     .qdev.reset = grlib_gptimer_reset,
 380     .qdev.size  = sizeof(GPTimerUnit),
 381     .qdev.props = (Property[]) {
 382         DEFINE_PROP_UINT32("frequency", GPTimerUnit, freq_hz,   40000000),
 383         DEFINE_PROP_UINT32("irq-line",  GPTimerUnit, irq_line,  8),
 384         DEFINE_PROP_UINT32("nr-timers", GPTimerUnit, nr_timers, 2),
 385         DEFINE_PROP_END_OF_LIST()
 386     }
 387 };
 388
 389 static void grlib_gptimer_register(void)
 390 {
 391     sysbus_register_withprop(&grlib_gptimer_info);
 392 }
 393
 394 device_init(grlib_gptimer_register)