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     MemoryRegion iomem;
  72
  73     uint32_t nr_timers;         /* Number of timers available */
  74     uint32_t freq_hz;           /* System frequency */
  75     uint32_t irq_line;          /* Base irq line */
  76
  77     GPTimer *timers;
  78
  79     /* registers */
  80     uint32_t scaler;
  81     uint32_t reload;
  82     uint32_t config;
  83 };
  84
  85 static void grlib_gptimer_enable(GPTimer *timer)
  86 {
  87     assert(timer != NULL);
  88
  89
  90     ptimer_stop(timer->ptimer);
  91
  92     if (!(timer->config & GPTIMER_ENABLE)) {
  93         /* Timer disabled */
  94         trace_grlib_gptimer_disabled(timer->id, timer->config);
  95         return;
  96     }
  97
  98     /* ptimer is triggered when the counter reach 0 but GPTimer is triggered at
  99        underflow. Set count + 1 to simulate the GPTimer behavior. */
 100
 101     trace_grlib_gptimer_enable(timer->id, timer->counter + 1);
 102
 103     ptimer_set_count(timer->ptimer, timer->counter + 1);
 104     ptimer_run(timer->ptimer, 1);
 105 }
 106
 107 static void grlib_gptimer_restart(GPTimer *timer)
 108 {
 109     assert(timer != NULL);
 110
 111     trace_grlib_gptimer_restart(timer->id, timer->reload);
 112
 113     timer->counter = timer->reload;
 114     grlib_gptimer_enable(timer);
 115 }
 116
 117 static void grlib_gptimer_set_scaler(GPTimerUnit *unit, uint32_t scaler)
 118 {
 119     int i = 0;
 120     uint32_t value = 0;
 121
 122     assert(unit != NULL);
 123
 124     if (scaler > 0) {
 125         value = unit->freq_hz / (scaler + 1);
 126     } else {
 127         value = unit->freq_hz;
 128     }
 129
 130     trace_grlib_gptimer_set_scaler(scaler, value);
 131
 132     for (i = 0; i < unit->nr_timers; i++) {
 133         ptimer_set_freq(unit->timers[i].ptimer, value);
 134     }
 135 }
 136
 137 static void grlib_gptimer_hit(void *opaque)
 138 {
 139     GPTimer *timer = opaque;
 140     assert(timer != NULL);
 141
 142     trace_grlib_gptimer_hit(timer->id);
 143
 144     /* Timer expired */
 145
 146     if (timer->config & GPTIMER_INT_ENABLE) {
 147         /* Set the pending bit (only unset by write in the config register) */
 148         timer->config |= GPTIMER_INT_PENDING;
 149         qemu_irq_pulse(timer->irq);
 150     }
 151
 152     if (timer->config & GPTIMER_RESTART) {
 153         grlib_gptimer_restart(timer);
 154     }
 155 }
 156
 157 static uint64_t grlib_gptimer_read(void *opaque, target_phys_addr_t addr,
 158                                    unsigned size)
 159 {
 160     GPTimerUnit        *unit  = opaque;
 161     target_phys_addr_t  timer_addr;
 162     int                 id;
 163     uint32_t            value = 0;
 164
 165     addr &= 0xff;
 166
 167     /* Unit registers */
 168     switch (addr) {
 169     case SCALER_OFFSET:
 170         trace_grlib_gptimer_readl(-1, addr, unit->scaler);
 171         return unit->scaler;
 172
 173     case SCALER_RELOAD_OFFSET:
 174         trace_grlib_gptimer_readl(-1, addr, unit->reload);
 175         return unit->reload;
 176
 177     case CONFIG_OFFSET:
 178         trace_grlib_gptimer_readl(-1, addr, unit->config);
 179         return unit->config;
 180
 181     default:
 182         break;
 183     }
 184
 185     timer_addr = (addr % TIMER_BASE);
 186     id         = (addr - TIMER_BASE) / TIMER_BASE;
 187
 188     if (id >= 0 && id < unit->nr_timers) {
 189
 190         /* GPTimer registers */
 191         switch (timer_addr) {
 192         case COUNTER_OFFSET:
 193             value = ptimer_get_count(unit->timers[id].ptimer);
 194             trace_grlib_gptimer_readl(id, addr, value);
 195             return value;
 196
 197         case COUNTER_RELOAD_OFFSET:
 198             value = unit->timers[id].reload;
 199             trace_grlib_gptimer_readl(id, addr, value);
 200             return value;
 201
 202         case CONFIG_OFFSET:
 203             trace_grlib_gptimer_readl(id, addr, unit->timers[id].config);
 204             return unit->timers[id].config;
 205
 206         default:
 207             break;
 208         }
 209
 210     }
 211
 212     trace_grlib_gptimer_readl(-1, addr, 0);
 213     return 0;
 214 }
 215
 216 static void grlib_gptimer_write(void *opaque, target_phys_addr_t addr,
 217                                 uint64_t value, unsigned size)
 218 {
 219     GPTimerUnit        *unit = opaque;
 220     target_phys_addr_t  timer_addr;
 221     int                 id;
 222
 223     addr &= 0xff;
 224
 225     /* Unit registers */
 226     switch (addr) {
 227     case SCALER_OFFSET:
 228         value &= 0xFFFF; /* clean up the value */
 229         unit->scaler = value;
 230         trace_grlib_gptimer_writel(-1, addr, unit->scaler);
 231         return;
 232
 233     case SCALER_RELOAD_OFFSET:
 234         value &= 0xFFFF; /* clean up the value */
 235         unit->reload = value;
 236         trace_grlib_gptimer_writel(-1, addr, unit->reload);
 237         grlib_gptimer_set_scaler(unit, value);
 238         return;
 239
 240     case CONFIG_OFFSET:
 241         /* Read Only (disable timer freeze not supported) */
 242         trace_grlib_gptimer_writel(-1, addr, 0);
 243         return;
 244
 245     default:
 246         break;
 247     }
 248
 249     timer_addr = (addr % TIMER_BASE);
 250     id         = (addr - TIMER_BASE) / TIMER_BASE;
 251
 252     if (id >= 0 && id < unit->nr_timers) {
 253
 254         /* GPTimer registers */
 255         switch (timer_addr) {
 256         case COUNTER_OFFSET:
 257             trace_grlib_gptimer_writel(id, addr, value);
 258             unit->timers[id].counter = value;
 259             grlib_gptimer_enable(&unit->timers[id]);
 260             return;
 261
 262         case COUNTER_RELOAD_OFFSET:
 263             trace_grlib_gptimer_writel(id, addr, value);
 264             unit->timers[id].reload = value;
 265             return;
 266
 267         case CONFIG_OFFSET:
 268             trace_grlib_gptimer_writel(id, addr, value);
 269
 270             if (value & GPTIMER_INT_PENDING) {
 271                 /* clear pending bit */
 272                 value &= ~GPTIMER_INT_PENDING;
 273             } else {
 274                 /* keep pending bit */
 275                 value |= unit->timers[id].config & GPTIMER_INT_PENDING;
 276             }
 277
 278             unit->timers[id].config = value;
 279
 280             /* gptimer_restart calls gptimer_enable, so if "enable" and "load"
 281                bits are present, we just have to call restart. */
 282
 283             if (value & GPTIMER_LOAD) {
 284                 grlib_gptimer_restart(&unit->timers[id]);
 285             } else if (value & GPTIMER_ENABLE) {
 286                 grlib_gptimer_enable(&unit->timers[id]);
 287             }
 288
 289             /* These fields must always be read as 0 */
 290             value &= ~(GPTIMER_LOAD & GPTIMER_DEBUG_HALT);
 291
 292             unit->timers[id].config = value;
 293             return;
 294
 295         default:
 296             break;
 297         }
 298
 299     }
 300
 301     trace_grlib_gptimer_writel(-1, addr, value);
 302 }
 303
 304 static const MemoryRegionOps grlib_gptimer_ops = {
 305     .read = grlib_gptimer_read,
 306     .write = grlib_gptimer_write,
 307     .endianness = DEVICE_NATIVE_ENDIAN,
 308     .valid = {
 309         .min_access_size = 4,
 310         .max_access_size = 4,
 311     },
 312 };
 313
 314 static void grlib_gptimer_reset(DeviceState *d)
 315 {
 316     GPTimerUnit *unit = container_of(d, GPTimerUnit, busdev.qdev);
 317     int          i    = 0;
 318
 319     assert(unit != NULL);
 320
 321     unit->scaler = 0;
 322     unit->reload = 0;
 323     unit->config = 0;
 324
 325     unit->config  = unit->nr_timers;
 326     unit->config |= unit->irq_line << 3;
 327     unit->config |= 1 << 8;     /* separate interrupt */
 328     unit->config |= 1 << 9;     /* Disable timer freeze */
 329
 330
 331     for (i = 0; i < unit->nr_timers; i++) {
 332         GPTimer *timer = &unit->timers[i];
 333
 334         timer->counter = 0;
 335         timer->reload = 0;
 336         timer->config = 0;
 337         ptimer_stop(timer->ptimer);
 338         ptimer_set_count(timer->ptimer, 0);
 339         ptimer_set_freq(timer->ptimer, unit->freq_hz);
 340     }
 341 }
 342
 343 static int grlib_gptimer_init(SysBusDevice *dev)
 344 {
 345     GPTimerUnit  *unit = FROM_SYSBUS(typeof(*unit), dev);
 346     unsigned int  i;
 347
 348     assert(unit->nr_timers > 0);
 349     assert(unit->nr_timers <= GPTIMER_MAX_TIMERS);
 350
 351     unit->timers = g_malloc0(sizeof unit->timers[0] * unit->nr_timers);
 352
 353     for (i = 0; i < unit->nr_timers; i++) {
 354         GPTimer *timer = &unit->timers[i];
 355
 356         timer->unit   = unit;
 357         timer->bh     = qemu_bh_new(grlib_gptimer_hit, timer);
 358         timer->ptimer = ptimer_init(timer->bh);
 359         timer->id     = i;
 360
 361         /* One IRQ line for each timer */
 362         sysbus_init_irq(dev, &timer->irq);
 363
 364         ptimer_set_freq(timer->ptimer, unit->freq_hz);
 365     }
 366
 367     memory_region_init_io(&unit->iomem, &grlib_gptimer_ops, unit, "gptimer",
 368                           UNIT_REG_SIZE + GPTIMER_REG_SIZE * unit->nr_timers);
 369
 370     sysbus_init_mmio(dev, &unit->iomem);
 371     return 0;
 372 }
 373
 374 static SysBusDeviceInfo grlib_gptimer_info = {
 375     .init       = grlib_gptimer_init,
 376     .qdev.name  = "grlib,gptimer",
 377     .qdev.reset = grlib_gptimer_reset,
 378     .qdev.size  = sizeof(GPTimerUnit),
 379     .qdev.props = (Property[]) {
 380         DEFINE_PROP_UINT32("frequency", GPTimerUnit, freq_hz,   40000000),
 381         DEFINE_PROP_UINT32("irq-line",  GPTimerUnit, irq_line,  8),
 382         DEFINE_PROP_UINT32("nr-timers", GPTimerUnit, nr_timers, 2),
 383         DEFINE_PROP_END_OF_LIST()
 384     }
 385 };
 386
 387 static void grlib_gptimer_register(void)
 388 {
 389     sysbus_register_withprop(&grlib_gptimer_info);
 390 }
 391
 392 device_init(grlib_gptimer_register)