hw/arm_timer.c

   1 /*
   2  * ARM PrimeCell Timer modules.
   3  *
   4  * Copyright (c) 2005-2006 CodeSourcery.
   5  * Written by Paul Brook
   6  *
   7  * This code is licenced under the GPL.
   8  */
   9
  10 #include "hw.h"
  11 #include "qemu-timer.h"
  12 #include "primecell.h"
  13
  14 /* Common timer implementation.  */
  15
  16 #define TIMER_CTRL_ONESHOT      (1 << 0)
  17 #define TIMER_CTRL_32BIT        (1 << 1)
  18 #define TIMER_CTRL_DIV1         (0 << 2)
  19 #define TIMER_CTRL_DIV16        (1 << 2)
  20 #define TIMER_CTRL_DIV256       (2 << 2)
  21 #define TIMER_CTRL_IE           (1 << 5)
  22 #define TIMER_CTRL_PERIODIC     (1 << 6)
  23 #define TIMER_CTRL_ENABLE       (1 << 7)
  24
  25 typedef struct {
  26     ptimer_state *timer;
  27     uint32_t control;
  28     uint32_t limit;
  29     int freq;
  30     int int_level;
  31     qemu_irq irq;
  32 } arm_timer_state;
  33
  34 /* Check all active timers, and schedule the next timer interrupt.  */
  35
  36 static void arm_timer_update(arm_timer_state *s)
  37 {
  38     /* Update interrupts.  */
  39     if (s->int_level && (s->control & TIMER_CTRL_IE)) {
  40         qemu_irq_raise(s->irq);
  41     } else {
  42         qemu_irq_lower(s->irq);
  43     }
  44 }
  45
  46 static uint32_t arm_timer_read(void *opaque, target_phys_addr_t offset)
  47 {
  48     arm_timer_state *s = (arm_timer_state *)opaque;
  49
  50     switch (offset >> 2) {
  51     case 0: /* TimerLoad */
  52     case 6: /* TimerBGLoad */
  53         return s->limit;
  54     case 1: /* TimerValue */
  55         return ptimer_get_count(s->timer);
  56     case 2: /* TimerControl */
  57         return s->control;
  58     case 4: /* TimerRIS */
  59         return s->int_level;
  60     case 5: /* TimerMIS */
  61         if ((s->control & TIMER_CTRL_IE) == 0)
  62             return 0;
  63         return s->int_level;
  64     default:
  65         cpu_abort (cpu_single_env, "arm_timer_read: Bad offset %x\n",
  66                    (int)offset);
  67         return 0;
  68     }
  69 }
  70
  71 /* Reset the timer limit after settings have changed.  */
  72 static void arm_timer_recalibrate(arm_timer_state *s, int reload)
  73 {
  74     uint32_t limit;
  75
  76     if ((s->control & TIMER_CTRL_PERIODIC) == 0) {
  77         /* Free running.  */
  78         if (s->control & TIMER_CTRL_32BIT)
  79             limit = 0xffffffff;
  80         else
  81             limit = 0xffff;
  82     } else {
  83           /* Periodic.  */
  84           limit = s->limit;
  85     }
  86     ptimer_set_limit(s->timer, limit, reload);
  87 }
  88
  89 static void arm_timer_write(void *opaque, target_phys_addr_t offset,
  90                             uint32_t value)
  91 {
  92     arm_timer_state *s = (arm_timer_state *)opaque;
  93     int freq;
  94
  95     switch (offset >> 2) {
  96     case 0: /* TimerLoad */
  97         s->limit = value;
  98         arm_timer_recalibrate(s, 1);
  99         break;
 100     case 1: /* TimerValue */
 101         /* ??? Linux seems to want to write to this readonly register.
 102            Ignore it.  */
 103         break;
 104     case 2: /* TimerControl */
 105         if (s->control & TIMER_CTRL_ENABLE) {
 106             /* Pause the timer if it is running.  This may cause some
 107                inaccuracy dure to rounding, but avoids a whole lot of other
 108                messyness.  */
 109             ptimer_stop(s->timer);
 110         }
 111         s->control = value;
 112         freq = s->freq;
 113         /* ??? Need to recalculate expiry time after changing divisor.  */
 114         switch ((value >> 2) & 3) {
 115         case 1: freq >>= 4; break;
 116         case 2: freq >>= 8; break;
 117         }
 118         arm_timer_recalibrate(s, 0);
 119         ptimer_set_freq(s->timer, freq);
 120         if (s->control & TIMER_CTRL_ENABLE) {
 121             /* Restart the timer if still enabled.  */
 122             ptimer_run(s->timer, (s->control & TIMER_CTRL_ONESHOT) != 0);
 123         }
 124         break;
 125     case 3: /* TimerIntClr */
 126         s->int_level = 0;
 127         break;
 128     case 6: /* TimerBGLoad */
 129         s->limit = value;
 130         arm_timer_recalibrate(s, 0);
 131         break;
 132     default:
 133         cpu_abort (cpu_single_env, "arm_timer_write: Bad offset %x\n",
 134                    (int)offset);
 135     }
 136     arm_timer_update(s);
 137 }
 138
 139 static void arm_timer_tick(void *opaque)
 140 {
 141     arm_timer_state *s = (arm_timer_state *)opaque;
 142     s->int_level = 1;
 143     arm_timer_update(s);
 144 }
 145
 146 static void arm_timer_save(QEMUFile *f, void *opaque)
 147 {
 148     arm_timer_state *s = (arm_timer_state *)opaque;
 149     qemu_put_be32(f, s->control);
 150     qemu_put_be32(f, s->limit);
 151     qemu_put_be32(f, s->int_level);
 152     qemu_put_ptimer(f, s->timer);
 153 }
 154
 155 static int arm_timer_load(QEMUFile *f, void *opaque, int version_id)
 156 {
 157     arm_timer_state *s = (arm_timer_state *)opaque;
 158
 159     if (version_id != 1)
 160         return -EINVAL;
 161
 162     s->control = qemu_get_be32(f);
 163     s->limit = qemu_get_be32(f);
 164     s->int_level = qemu_get_be32(f);
 165     qemu_get_ptimer(f, s->timer);
 166     return 0;
 167 }
 168
 169 static void *arm_timer_init(uint32_t freq, qemu_irq irq)
 170 {
 171     arm_timer_state *s;
 172     QEMUBH *bh;
 173
 174     s = (arm_timer_state *)qemu_mallocz(sizeof(arm_timer_state));
 175     s->irq = irq;
 176     s->freq = freq;
 177     s->control = TIMER_CTRL_IE;
 178
 179     bh = qemu_bh_new(arm_timer_tick, s);
 180     s->timer = ptimer_init(bh);
 181     register_savevm("arm_timer", -1, 1, arm_timer_save, arm_timer_load, s);
 182     return s;
 183 }
 184
 185 /* ARM PrimeCell SP804 dual timer module.
 186    Docs for this device don't seem to be publicly available.  This
 187    implementation is based on guesswork, the linux kernel sources and the
 188    Integrator/CP timer modules.  */
 189
 190 typedef struct {
 191     void *timer[2];
 192     int level[2];
 193     qemu_irq irq;
 194 } sp804_state;
 195
 196 /* Merge the IRQs from the two component devices.  */
 197 static void sp804_set_irq(void *opaque, int irq, int level)
 198 {
 199     sp804_state *s = (sp804_state *)opaque;
 200
 201     s->level[irq] = level;
 202     qemu_set_irq(s->irq, s->level[0] || s->level[1]);
 203 }
 204
 205 static uint32_t sp804_read(void *opaque, target_phys_addr_t offset)
 206 {
 207     sp804_state *s = (sp804_state *)opaque;
 208
 209     /* ??? Don't know the PrimeCell ID for this device.  */
 210     if (offset < 0x20) {
 211         return arm_timer_read(s->timer[0], offset);
 212     } else {
 213         return arm_timer_read(s->timer[1], offset - 0x20);
 214     }
 215 }
 216
 217 static void sp804_write(void *opaque, target_phys_addr_t offset,
 218                         uint32_t value)
 219 {
 220     sp804_state *s = (sp804_state *)opaque;
 221
 222     if (offset < 0x20) {
 223         arm_timer_write(s->timer[0], offset, value);
 224     } else {
 225         arm_timer_write(s->timer[1], offset - 0x20, value);
 226     }
 227 }
 228
 229 static CPUReadMemoryFunc *sp804_readfn[] = {
 230    sp804_read,
 231    sp804_read,
 232    sp804_read
 233 };
 234
 235 static CPUWriteMemoryFunc *sp804_writefn[] = {
 236    sp804_write,
 237    sp804_write,
 238    sp804_write
 239 };
 240
 241 static void sp804_save(QEMUFile *f, void *opaque)
 242 {
 243     sp804_state *s = (sp804_state *)opaque;
 244     qemu_put_be32(f, s->level[0]);
 245     qemu_put_be32(f, s->level[1]);
 246 }
 247
 248 static int sp804_load(QEMUFile *f, void *opaque, int version_id)
 249 {
 250     sp804_state *s = (sp804_state *)opaque;
 251
 252     if (version_id != 1)
 253         return -EINVAL;
 254
 255     s->level[0] = qemu_get_be32(f);
 256     s->level[1] = qemu_get_be32(f);
 257     return 0;
 258 }
 259
 260 void sp804_init(uint32_t base, qemu_irq irq)
 261 {
 262     int iomemtype;
 263     sp804_state *s;
 264     qemu_irq *qi;
 265
 266     s = (sp804_state *)qemu_mallocz(sizeof(sp804_state));
 267     qi = qemu_allocate_irqs(sp804_set_irq, s, 2);
 268     s->irq = irq;
 269     /* ??? The timers are actually configurable between 32kHz and 1MHz, but
 270        we don't implement that.  */
 271     s->timer[0] = arm_timer_init(1000000, qi[0]);
 272     s->timer[1] = arm_timer_init(1000000, qi[1]);
 273     iomemtype = cpu_register_io_memory(0, sp804_readfn,
 274                                        sp804_writefn, s);
 275     cpu_register_physical_memory(base, 0x00001000, iomemtype);
 276     register_savevm("sp804", -1, 1, sp804_save, sp804_load, s);
 277 }
 278
 279
 280 /* Integrator/CP timer module.  */
 281
 282 typedef struct {
 283     void *timer[3];
 284 } icp_pit_state;
 285
 286 static uint32_t icp_pit_read(void *opaque, target_phys_addr_t offset)
 287 {
 288     icp_pit_state *s = (icp_pit_state *)opaque;
 289     int n;
 290
 291     /* ??? Don't know the PrimeCell ID for this device.  */
 292     n = offset >> 8;
 293     if (n > 3)
 294         cpu_abort(cpu_single_env, "sp804_read: Bad timer %d\n", n);
 295
 296     return arm_timer_read(s->timer[n], offset & 0xff);
 297 }
 298
 299 static void icp_pit_write(void *opaque, target_phys_addr_t offset,
 300                           uint32_t value)
 301 {
 302     icp_pit_state *s = (icp_pit_state *)opaque;
 303     int n;
 304
 305     n = offset >> 8;
 306     if (n > 3)
 307         cpu_abort(cpu_single_env, "sp804_write: Bad timer %d\n", n);
 308
 309     arm_timer_write(s->timer[n], offset & 0xff, value);
 310 }
 311
 312
 313 static CPUReadMemoryFunc *icp_pit_readfn[] = {
 314    icp_pit_read,
 315    icp_pit_read,
 316    icp_pit_read
 317 };
 318
 319 static CPUWriteMemoryFunc *icp_pit_writefn[] = {
 320    icp_pit_write,
 321    icp_pit_write,
 322    icp_pit_write
 323 };
 324
 325 void icp_pit_init(uint32_t base, qemu_irq *pic, int irq)
 326 {
 327     int iomemtype;
 328     icp_pit_state *s;
 329
 330     s = (icp_pit_state *)qemu_mallocz(sizeof(icp_pit_state));
 331     /* Timer 0 runs at the system clock speed (40MHz).  */
 332     s->timer[0] = arm_timer_init(40000000, pic[irq]);
 333     /* The other two timers run at 1MHz.  */
 334     s->timer[1] = arm_timer_init(1000000, pic[irq + 1]);
 335     s->timer[2] = arm_timer_init(1000000, pic[irq + 2]);
 336
 337     iomemtype = cpu_register_io_memory(0, icp_pit_readfn,
 338                                        icp_pit_writefn, s);
 339     cpu_register_physical_memory(base, 0x00001000, iomemtype);
 340     /* This device has no state to save/restore.  The component timers will
 341        save themselves.  */
 342 }