hw/timer/a9gtimer.c

   1 /*
   2  * Global peripheral timer block for ARM A9MP
   3  *
   4  * (C) 2013 Xilinx Inc.
   5  *
   6  * Written by François LEGAL
   7  * Written by Peter Crosthwaite <peter.crosthwaite@xilinx.com>
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License
  11  * as published by the Free Software Foundation; either version
  12  * 2 of the License, or (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License along
  20  * with this program; if not, see <http://www.gnu.org/licenses/>.
  21  */
  22
  23 #include "qemu/osdep.h"
  24 #include "hw/hw.h"
  25 #include "hw/irq.h"
  26 #include "hw/qdev-properties.h"
  27 #include "hw/timer/a9gtimer.h"
  28 #include "migration/vmstate.h"
  29 #include "qapi/error.h"
  30 #include "qemu/timer.h"
  31 #include "qemu/bitops.h"
  32 #include "qemu/log.h"
  33 #include "qemu/module.h"
  34 #include "hw/core/cpu.h"
  35
  36 #ifndef A9_GTIMER_ERR_DEBUG
  37 #define A9_GTIMER_ERR_DEBUG 0
  38 #endif
  39
  40 #define DB_PRINT_L(level, ...) do { \
  41     if (A9_GTIMER_ERR_DEBUG > (level)) { \
  42         fprintf(stderr,  ": %s: ", __func__); \
  43         fprintf(stderr, ## __VA_ARGS__); \
  44     } \
  45 } while (0)
  46
  47 #define DB_PRINT(...) DB_PRINT_L(0, ## __VA_ARGS__)
  48
  49 static inline int a9_gtimer_get_current_cpu(A9GTimerState *s)
  50 {
  51     if (current_cpu->cpu_index >= s->num_cpu) {
  52         hw_error("a9gtimer: num-cpu %d but this cpu is %d!\n",
  53                  s->num_cpu, current_cpu->cpu_index);
  54     }
  55     return current_cpu->cpu_index;
  56 }
  57
  58 static inline uint64_t a9_gtimer_get_conv(A9GTimerState *s)
  59 {
  60     uint64_t prescale = extract32(s->control, R_CONTROL_PRESCALER_SHIFT,
  61                                   R_CONTROL_PRESCALER_LEN);
  62
  63     return (prescale + 1) * 10;
  64 }
  65
  66 static A9GTimerUpdate a9_gtimer_get_update(A9GTimerState *s)
  67 {
  68     A9GTimerUpdate ret;
  69
  70     ret.now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
  71     ret.new = s->ref_counter +
  72               (ret.now - s->cpu_ref_time) / a9_gtimer_get_conv(s);
  73     return ret;
  74 }
  75
  76 static void a9_gtimer_update(A9GTimerState *s, bool sync)
  77 {
  78
  79     A9GTimerUpdate update = a9_gtimer_get_update(s);
  80     int i;
  81     int64_t next_cdiff = 0;
  82
  83     for (i = 0; i < s->num_cpu; ++i) {
  84         A9GTimerPerCPU *gtb = &s->per_cpu[i];
  85         int64_t cdiff = 0;
  86
  87         if ((s->control & R_CONTROL_TIMER_ENABLE) &&
  88                 (gtb->control & R_CONTROL_COMP_ENABLE)) {
  89             /* R2p0+, where the compare function is >= */
  90             if (gtb->compare < update.new) {
  91                 DB_PRINT("Compare event happened for CPU %d\n", i);
  92                 gtb->status = 1;
  93                 if (gtb->control & R_CONTROL_AUTO_INCREMENT && gtb->inc) {
  94                     uint64_t inc =
  95                         QEMU_ALIGN_UP(update.new - gtb->compare, gtb->inc);
  96                     DB_PRINT("Auto incrementing timer compare by %"
  97                                                         PRId64 "\n", inc);
  98                     gtb->compare += inc;
  99                 }
 100             }
 101             cdiff = (int64_t)gtb->compare - (int64_t)update.new + 1;
 102             if (cdiff > 0 && (cdiff < next_cdiff || !next_cdiff)) {
 103                 next_cdiff = cdiff;
 104             }
 105         }
 106
 107         qemu_set_irq(gtb->irq,
 108                      gtb->status && (gtb->control & R_CONTROL_IRQ_ENABLE));
 109     }
 110
 111     timer_del(s->timer);
 112     if (next_cdiff) {
 113         DB_PRINT("scheduling qemu_timer to fire again in %"
 114                  PRIx64 " cycles\n", next_cdiff);
 115         timer_mod(s->timer, update.now + next_cdiff * a9_gtimer_get_conv(s));
 116     }
 117
 118     if (s->control & R_CONTROL_TIMER_ENABLE) {
 119         s->counter = update.new;
 120     }
 121
 122     if (sync) {
 123         s->cpu_ref_time = update.now;
 124         s->ref_counter = s->counter;
 125     }
 126 }
 127
 128 static void a9_gtimer_update_no_sync(void *opaque)
 129 {
 130     A9GTimerState *s = A9_GTIMER(opaque);
 131
 132     a9_gtimer_update(s, false);
 133 }
 134
 135 static uint64_t a9_gtimer_read(void *opaque, hwaddr addr, unsigned size)
 136 {
 137     A9GTimerPerCPU *gtb = (A9GTimerPerCPU *)opaque;
 138     A9GTimerState *s = gtb->parent;
 139     A9GTimerUpdate update;
 140     uint64_t ret = 0;
 141     int shift = 0;
 142
 143     switch (addr) {
 144     case R_COUNTER_HI:
 145         shift = 32;
 146         /* fallthrough */
 147     case R_COUNTER_LO:
 148         update = a9_gtimer_get_update(s);
 149         ret = extract64(update.new, shift, 32);
 150         break;
 151     case R_CONTROL:
 152         ret = s->control | gtb->control;
 153         break;
 154     case R_INTERRUPT_STATUS:
 155         ret = gtb->status;
 156         break;
 157     case R_COMPARATOR_HI:
 158         shift = 32;
 159         /* fallthrough */
 160     case R_COMPARATOR_LO:
 161         ret = extract64(gtb->compare, shift, 32);
 162         break;
 163     case R_AUTO_INCREMENT:
 164         ret =  gtb->inc;
 165         break;
 166     default:
 167         qemu_log_mask(LOG_GUEST_ERROR, "bad a9gtimer register: %x\n",
 168                       (unsigned)addr);
 169         return 0;
 170     }
 171
 172     DB_PRINT("addr:%#x data:%#08" PRIx64 "\n", (unsigned)addr, ret);
 173     return ret;
 174 }
 175
 176 static void a9_gtimer_write(void *opaque, hwaddr addr, uint64_t value,
 177                             unsigned size)
 178 {
 179     A9GTimerPerCPU *gtb = (A9GTimerPerCPU *)opaque;
 180     A9GTimerState *s = gtb->parent;
 181     int shift = 0;
 182
 183     DB_PRINT("addr:%#x data:%#08" PRIx64 "\n", (unsigned)addr, value);
 184
 185     switch (addr) {
 186     case R_COUNTER_HI:
 187         shift = 32;
 188         /* fallthrough */
 189     case R_COUNTER_LO:
 190         /*
 191          * Keep it simple - ARM docco explicitly says to disable timer before
 192          * modding it, so don't bother trying to do all the difficult on the fly
 193          * timer modifications - (if they even work in real hardware??).
 194          */
 195         if (s->control & R_CONTROL_TIMER_ENABLE) {
 196             qemu_log_mask(LOG_GUEST_ERROR, "Cannot mod running ARM gtimer\n");
 197             return;
 198         }
 199         s->counter = deposit64(s->counter, shift, 32, value);
 200         return;
 201     case R_CONTROL:
 202         a9_gtimer_update(s, (value ^ s->control) & R_CONTROL_NEEDS_SYNC);
 203         gtb->control = value & R_CONTROL_BANKED;
 204         s->control = value & ~R_CONTROL_BANKED;
 205         break;
 206     case R_INTERRUPT_STATUS:
 207         a9_gtimer_update(s, false);
 208         gtb->status &= ~value;
 209         break;
 210     case R_COMPARATOR_HI:
 211         shift = 32;
 212         /* fallthrough */
 213     case R_COMPARATOR_LO:
 214         a9_gtimer_update(s, false);
 215         gtb->compare = deposit64(gtb->compare, shift, 32, value);
 216         break;
 217     case R_AUTO_INCREMENT:
 218         gtb->inc = value;
 219         return;
 220     default:
 221         return;
 222     }
 223
 224     a9_gtimer_update(s, false);
 225 }
 226
 227 /* Wrapper functions to implement the "read global timer for
 228  * the current CPU" memory regions.
 229  */
 230 static uint64_t a9_gtimer_this_read(void *opaque, hwaddr addr,
 231                                     unsigned size)
 232 {
 233     A9GTimerState *s = A9_GTIMER(opaque);
 234     int id = a9_gtimer_get_current_cpu(s);
 235
 236     /* no \n so concatenates with message from read fn */
 237     DB_PRINT("CPU:%d:", id);
 238
 239     return a9_gtimer_read(&s->per_cpu[id], addr, size);
 240 }
 241
 242 static void a9_gtimer_this_write(void *opaque, hwaddr addr,
 243                                  uint64_t value, unsigned size)
 244 {
 245     A9GTimerState *s = A9_GTIMER(opaque);
 246     int id = a9_gtimer_get_current_cpu(s);
 247
 248     /* no \n so concatenates with message from write fn */
 249     DB_PRINT("CPU:%d:", id);
 250
 251     a9_gtimer_write(&s->per_cpu[id], addr, value, size);
 252 }
 253
 254 static const MemoryRegionOps a9_gtimer_this_ops = {
 255     .read = a9_gtimer_this_read,
 256     .write = a9_gtimer_this_write,
 257     .valid = {
 258         .min_access_size = 4,
 259         .max_access_size = 4,
 260     },
 261     .endianness = DEVICE_NATIVE_ENDIAN,
 262 };
 263
 264 static const MemoryRegionOps a9_gtimer_ops = {
 265     .read = a9_gtimer_read,
 266     .write = a9_gtimer_write,
 267     .valid = {
 268         .min_access_size = 4,
 269         .max_access_size = 4,
 270     },
 271     .endianness = DEVICE_NATIVE_ENDIAN,
 272 };
 273
 274 static void a9_gtimer_reset(DeviceState *dev)
 275 {
 276     A9GTimerState *s = A9_GTIMER(dev);
 277     int i;
 278
 279     s->counter = 0;
 280     s->control = 0;
 281
 282     for (i = 0; i < s->num_cpu; i++) {
 283         A9GTimerPerCPU *gtb = &s->per_cpu[i];
 284
 285         gtb->control = 0;
 286         gtb->status = 0;
 287         gtb->compare = 0;
 288         gtb->inc = 0;
 289     }
 290     a9_gtimer_update(s, false);
 291 }
 292
 293 static void a9_gtimer_realize(DeviceState *dev, Error **errp)
 294 {
 295     A9GTimerState *s = A9_GTIMER(dev);
 296     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
 297     int i;
 298
 299     if (s->num_cpu < 1 || s->num_cpu > A9_GTIMER_MAX_CPUS) {
 300         error_setg(errp, "%s: num-cpu must be between 1 and %d",
 301                    __func__, A9_GTIMER_MAX_CPUS);
 302         return;
 303     }
 304
 305     memory_region_init_io(&s->iomem, OBJECT(dev), &a9_gtimer_this_ops, s,
 306                           "a9gtimer shared", 0x20);
 307     sysbus_init_mmio(sbd, &s->iomem);
 308     s->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, a9_gtimer_update_no_sync, s);
 309
 310     for (i = 0; i < s->num_cpu; i++) {
 311         A9GTimerPerCPU *gtb = &s->per_cpu[i];
 312
 313         gtb->parent = s;
 314         sysbus_init_irq(sbd, &gtb->irq);
 315         memory_region_init_io(&gtb->iomem, OBJECT(dev), &a9_gtimer_ops, gtb,
 316                               "a9gtimer per cpu", 0x20);
 317         sysbus_init_mmio(sbd, &gtb->iomem);
 318     }
 319 }
 320
 321 static const VMStateDescription vmstate_a9_gtimer_per_cpu = {
 322     .name = "arm.cortex-a9-global-timer.percpu",
 323     .version_id = 1,
 324     .minimum_version_id = 1,
 325     .fields = (VMStateField[]) {
 326         VMSTATE_UINT32(control, A9GTimerPerCPU),
 327         VMSTATE_UINT64(compare, A9GTimerPerCPU),
 328         VMSTATE_UINT32(status, A9GTimerPerCPU),
 329         VMSTATE_UINT32(inc, A9GTimerPerCPU),
 330         VMSTATE_END_OF_LIST()
 331     }
 332 };
 333
 334 static const VMStateDescription vmstate_a9_gtimer = {
 335     .name = "arm.cortex-a9-global-timer",
 336     .version_id = 1,
 337     .minimum_version_id = 1,
 338     .fields = (VMStateField[]) {
 339         VMSTATE_TIMER_PTR(timer, A9GTimerState),
 340         VMSTATE_UINT64(counter, A9GTimerState),
 341         VMSTATE_UINT64(ref_counter, A9GTimerState),
 342         VMSTATE_UINT64(cpu_ref_time, A9GTimerState),
 343         VMSTATE_STRUCT_VARRAY_UINT32(per_cpu, A9GTimerState, num_cpu,
 344                                      1, vmstate_a9_gtimer_per_cpu,
 345                                      A9GTimerPerCPU),
 346         VMSTATE_END_OF_LIST()
 347     }
 348 };
 349
 350 static Property a9_gtimer_properties[] = {
 351     DEFINE_PROP_UINT32("num-cpu", A9GTimerState, num_cpu, 0),
 352     DEFINE_PROP_END_OF_LIST()
 353 };
 354
 355 static void a9_gtimer_class_init(ObjectClass *klass, void *data)
 356 {
 357     DeviceClass *dc = DEVICE_CLASS(klass);
 358
 359     dc->realize = a9_gtimer_realize;
 360     dc->vmsd = &vmstate_a9_gtimer;
 361     dc->reset = a9_gtimer_reset;
 362     device_class_set_props(dc, a9_gtimer_properties);
 363 }
 364
 365 static const TypeInfo a9_gtimer_info = {
 366     .name          = TYPE_A9_GTIMER,
 367     .parent        = TYPE_SYS_BUS_DEVICE,
 368     .instance_size = sizeof(A9GTimerState),
 369     .class_init    = a9_gtimer_class_init,
 370 };
 371
 372 static void a9_gtimer_register_types(void)
 373 {
 374     type_register_static(&a9_gtimer_info);
 375 }
 376
 377 type_init(a9_gtimer_register_types)