hw/watchdog/wdt_i6300esb.c

   1 /*
   2  * Virtual hardware watchdog.
   3  *
   4  * Copyright (C) 2009 Red Hat Inc.
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version 2
   9  * of the License, or (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  18  *
  19  * By Richard W.M. Jones (rjones@redhat.com).
  20  */
  21
  22 #include "qemu/osdep.h"
  23
  24 #include "qemu/module.h"
  25 #include "qemu/timer.h"
  26 #include "sysemu/watchdog.h"
  27 #include "hw/pci/pci.h"
  28 #include "migration/vmstate.h"
  29
  30 /*#define I6300ESB_DEBUG 1*/
  31
  32 #ifdef I6300ESB_DEBUG
  33 #define i6300esb_debug(fs,...) \
  34     fprintf(stderr,"i6300esb: %s: "fs,__func__,##__VA_ARGS__)
  35 #else
  36 #define i6300esb_debug(fs,...)
  37 #endif
  38
  39 /* PCI configuration registers */
  40 #define ESB_CONFIG_REG  0x60            /* Config register                   */
  41 #define ESB_LOCK_REG    0x68            /* WDT lock register                 */
  42
  43 /* Memory mapped registers (offset from base address) */
  44 #define ESB_TIMER1_REG  0x00            /* Timer1 value after each reset     */
  45 #define ESB_TIMER2_REG  0x04            /* Timer2 value after each reset     */
  46 #define ESB_GINTSR_REG  0x08            /* General Interrupt Status Register */
  47 #define ESB_RELOAD_REG  0x0c            /* Reload register                   */
  48
  49 /* Lock register bits */
  50 #define ESB_WDT_FUNC    (0x01 << 2)   /* Watchdog functionality            */
  51 #define ESB_WDT_ENABLE  (0x01 << 1)   /* Enable WDT                        */
  52 #define ESB_WDT_LOCK    (0x01 << 0)   /* Lock (nowayout)                   */
  53
  54 /* Config register bits */
  55 #define ESB_WDT_REBOOT  (0x01 << 5)   /* Enable reboot on timeout          */
  56 #define ESB_WDT_FREQ    (0x01 << 2)   /* Decrement frequency               */
  57 #define ESB_WDT_INTTYPE (0x11 << 0)   /* Interrupt type on timer1 timeout  */
  58
  59 /* Reload register bits */
  60 #define ESB_WDT_RELOAD  (0x01 << 8)    /* prevent timeout                   */
  61
  62 /* Magic constants */
  63 #define ESB_UNLOCK1     0x80            /* Step 1 to unlock reset registers  */
  64 #define ESB_UNLOCK2     0x86            /* Step 2 to unlock reset registers  */
  65
  66 /* Device state. */
  67 struct I6300State {
  68     PCIDevice dev;
  69     MemoryRegion io_mem;
  70
  71     int reboot_enabled;         /* "Reboot" on timer expiry.  The real action
  72                                  * performed depends on the -watchdog-action
  73                                  * param passed on QEMU command line.
  74                                  */
  75     int clock_scale;            /* Clock scale. */
  76 #define CLOCK_SCALE_1KHZ 0
  77 #define CLOCK_SCALE_1MHZ 1
  78
  79     int int_type;               /* Interrupt type generated. */
  80 #define INT_TYPE_IRQ 0          /* APIC 1, INT 10 */
  81 #define INT_TYPE_SMI 2
  82 #define INT_TYPE_DISABLED 3
  83
  84     int free_run;               /* If true, reload timer on expiry. */
  85     int locked;                 /* If true, enabled field cannot be changed. */
  86     int enabled;                /* If true, watchdog is enabled. */
  87
  88     QEMUTimer *timer;           /* The actual watchdog timer. */
  89
  90     uint32_t timer1_preload;    /* Values preloaded into timer1, timer2. */
  91     uint32_t timer2_preload;
  92     int stage;                  /* Stage (1 or 2). */
  93
  94     int unlock_state;           /* Guest writes 0x80, 0x86 to unlock the
  95                                  * registers, and we transition through
  96                                  * states 0 -> 1 -> 2 when this happens.
  97                                  */
  98
  99     int previous_reboot_flag;   /* If the watchdog caused the previous
 100                                  * reboot, this flag will be set.
 101                                  */
 102 };
 103
 104 typedef struct I6300State I6300State;
 105
 106 #define TYPE_WATCHDOG_I6300ESB_DEVICE "i6300esb"
 107 #define WATCHDOG_I6300ESB_DEVICE(obj) \
 108     OBJECT_CHECK(I6300State, (obj), TYPE_WATCHDOG_I6300ESB_DEVICE)
 109
 110 /* This function is called when the watchdog has either been enabled
 111  * (hence it starts counting down) or has been keep-alived.
 112  */
 113 static void i6300esb_restart_timer(I6300State *d, int stage)
 114 {
 115     int64_t timeout;
 116
 117     if (!d->enabled)
 118         return;
 119
 120     d->stage = stage;
 121
 122     if (d->stage <= 1)
 123         timeout = d->timer1_preload;
 124     else
 125         timeout = d->timer2_preload;
 126
 127     if (d->clock_scale == CLOCK_SCALE_1KHZ)
 128         timeout <<= 15;
 129     else
 130         timeout <<= 5;
 131
 132     /* Get the timeout in nanoseconds. */
 133
 134     timeout = timeout * 30; /* on a PCI bus, 1 tick is 30 ns*/
 135
 136     i6300esb_debug("stage %d, timeout %" PRIi64 "\n", d->stage, timeout);
 137
 138     timer_mod(d->timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + timeout);
 139 }
 140
 141 /* This is called when the guest disables the watchdog. */
 142 static void i6300esb_disable_timer(I6300State *d)
 143 {
 144     i6300esb_debug("timer disabled\n");
 145
 146     timer_del(d->timer);
 147 }
 148
 149 static void i6300esb_reset(DeviceState *dev)
 150 {
 151     PCIDevice *pdev = PCI_DEVICE(dev);
 152     I6300State *d = WATCHDOG_I6300ESB_DEVICE(pdev);
 153
 154     i6300esb_debug("I6300State = %p\n", d);
 155
 156     i6300esb_disable_timer(d);
 157
 158     /* NB: Don't change d->previous_reboot_flag in this function. */
 159
 160     d->reboot_enabled = 1;
 161     d->clock_scale = CLOCK_SCALE_1KHZ;
 162     d->int_type = INT_TYPE_IRQ;
 163     d->free_run = 0;
 164     d->locked = 0;
 165     d->enabled = 0;
 166     d->timer1_preload = 0xfffff;
 167     d->timer2_preload = 0xfffff;
 168     d->stage = 1;
 169     d->unlock_state = 0;
 170 }
 171
 172 /* This function is called when the watchdog expires.  Note that
 173  * the hardware has two timers, and so expiry happens in two stages.
 174  * If d->stage == 1 then we perform the first stage action (usually,
 175  * sending an interrupt) and then restart the timer again for the
 176  * second stage.  If the second stage expires then the watchdog
 177  * really has run out.
 178  */
 179 static void i6300esb_timer_expired(void *vp)
 180 {
 181     I6300State *d = vp;
 182
 183     i6300esb_debug("stage %d\n", d->stage);
 184
 185     if (d->stage == 1) {
 186         /* What to do at the end of stage 1? */
 187         switch (d->int_type) {
 188         case INT_TYPE_IRQ:
 189             fprintf(stderr, "i6300esb_timer_expired: I would send APIC 1 INT 10 here if I knew how (XXX)\n");
 190             break;
 191         case INT_TYPE_SMI:
 192             fprintf(stderr, "i6300esb_timer_expired: I would send SMI here if I knew how (XXX)\n");
 193             break;
 194         }
 195
 196         /* Start the second stage. */
 197         i6300esb_restart_timer(d, 2);
 198     } else {
 199         /* Second stage expired, reboot for real. */
 200         if (d->reboot_enabled) {
 201             d->previous_reboot_flag = 1;
 202             watchdog_perform_action(); /* This reboots, exits, etc */
 203             i6300esb_reset(DEVICE(d));
 204         }
 205
 206         /* In "free running mode" we start stage 1 again. */
 207         if (d->free_run)
 208             i6300esb_restart_timer(d, 1);
 209     }
 210 }
 211
 212 static void i6300esb_config_write(PCIDevice *dev, uint32_t addr,
 213                                   uint32_t data, int len)
 214 {
 215     I6300State *d = WATCHDOG_I6300ESB_DEVICE(dev);
 216     int old;
 217
 218     i6300esb_debug("addr = %x, data = %x, len = %d\n", addr, data, len);
 219
 220     if (addr == ESB_CONFIG_REG && len == 2) {
 221         d->reboot_enabled = (data & ESB_WDT_REBOOT) == 0;
 222         d->clock_scale =
 223             (data & ESB_WDT_FREQ) != 0 ? CLOCK_SCALE_1MHZ : CLOCK_SCALE_1KHZ;
 224         d->int_type = (data & ESB_WDT_INTTYPE);
 225     } else if (addr == ESB_LOCK_REG && len == 1) {
 226         if (!d->locked) {
 227             d->locked = (data & ESB_WDT_LOCK) != 0;
 228             d->free_run = (data & ESB_WDT_FUNC) != 0;
 229             old = d->enabled;
 230             d->enabled = (data & ESB_WDT_ENABLE) != 0;
 231             if (!old && d->enabled) /* Enabled transitioned from 0 -> 1 */
 232                 i6300esb_restart_timer(d, 1);
 233             else if (!d->enabled)
 234                 i6300esb_disable_timer(d);
 235         }
 236     } else {
 237         pci_default_write_config(dev, addr, data, len);
 238     }
 239 }
 240
 241 static uint32_t i6300esb_config_read(PCIDevice *dev, uint32_t addr, int len)
 242 {
 243     I6300State *d = WATCHDOG_I6300ESB_DEVICE(dev);
 244     uint32_t data;
 245
 246     i6300esb_debug ("addr = %x, len = %d\n", addr, len);
 247
 248     if (addr == ESB_CONFIG_REG && len == 2) {
 249         data =
 250             (d->reboot_enabled ? 0 : ESB_WDT_REBOOT) |
 251             (d->clock_scale == CLOCK_SCALE_1MHZ ? ESB_WDT_FREQ : 0) |
 252             d->int_type;
 253         return data;
 254     } else if (addr == ESB_LOCK_REG && len == 1) {
 255         data =
 256             (d->free_run ? ESB_WDT_FUNC : 0) |
 257             (d->locked ? ESB_WDT_LOCK : 0) |
 258             (d->enabled ? ESB_WDT_ENABLE : 0);
 259         return data;
 260     } else {
 261         return pci_default_read_config(dev, addr, len);
 262     }
 263 }
 264
 265 static uint32_t i6300esb_mem_readb(void *vp, hwaddr addr)
 266 {
 267     i6300esb_debug ("addr = %x\n", (int) addr);
 268
 269     return 0;
 270 }
 271
 272 static uint32_t i6300esb_mem_readw(void *vp, hwaddr addr)
 273 {
 274     uint32_t data = 0;
 275     I6300State *d = vp;
 276
 277     i6300esb_debug("addr = %x\n", (int) addr);
 278
 279     if (addr == 0xc) {
 280         /* The previous reboot flag is really bit 9, but there is
 281          * a bug in the Linux driver where it thinks it's bit 12.
 282          * Set both.
 283          */
 284         data = d->previous_reboot_flag ? 0x1200 : 0;
 285     }
 286
 287     return data;
 288 }
 289
 290 static uint32_t i6300esb_mem_readl(void *vp, hwaddr addr)
 291 {
 292     i6300esb_debug("addr = %x\n", (int) addr);
 293
 294     return 0;
 295 }
 296
 297 static void i6300esb_mem_writeb(void *vp, hwaddr addr, uint32_t val)
 298 {
 299     I6300State *d = vp;
 300
 301     i6300esb_debug("addr = %x, val = %x\n", (int) addr, val);
 302
 303     if (addr == 0xc && val == 0x80)
 304         d->unlock_state = 1;
 305     else if (addr == 0xc && val == 0x86 && d->unlock_state == 1)
 306         d->unlock_state = 2;
 307 }
 308
 309 static void i6300esb_mem_writew(void *vp, hwaddr addr, uint32_t val)
 310 {
 311     I6300State *d = vp;
 312
 313     i6300esb_debug("addr = %x, val = %x\n", (int) addr, val);
 314
 315     if (addr == 0xc && val == 0x80)
 316         d->unlock_state = 1;
 317     else if (addr == 0xc && val == 0x86 && d->unlock_state == 1)
 318         d->unlock_state = 2;
 319     else {
 320         if (d->unlock_state == 2) {
 321             if (addr == 0xc) {
 322                 if ((val & 0x100) != 0)
 323                     /* This is the "ping" from the userspace watchdog in
 324                      * the guest ...
 325                      */
 326                     i6300esb_restart_timer(d, 1);
 327
 328                 /* Setting bit 9 resets the previous reboot flag.
 329                  * There's a bug in the Linux driver where it sets
 330                  * bit 12 instead.
 331                  */
 332                 if ((val & 0x200) != 0 || (val & 0x1000) != 0) {
 333                     d->previous_reboot_flag = 0;
 334                 }
 335             }
 336
 337             d->unlock_state = 0;
 338         }
 339     }
 340 }
 341
 342 static void i6300esb_mem_writel(void *vp, hwaddr addr, uint32_t val)
 343 {
 344     I6300State *d = vp;
 345
 346     i6300esb_debug ("addr = %x, val = %x\n", (int) addr, val);
 347
 348     if (addr == 0xc && val == 0x80)
 349         d->unlock_state = 1;
 350     else if (addr == 0xc && val == 0x86 && d->unlock_state == 1)
 351         d->unlock_state = 2;
 352     else {
 353         if (d->unlock_state == 2) {
 354             if (addr == 0)
 355                 d->timer1_preload = val & 0xfffff;
 356             else if (addr == 4)
 357                 d->timer2_preload = val & 0xfffff;
 358
 359             d->unlock_state = 0;
 360         }
 361     }
 362 }
 363
 364 static uint64_t i6300esb_mem_readfn(void *opaque, hwaddr addr, unsigned size)
 365 {
 366     switch (size) {
 367     case 1:
 368         return i6300esb_mem_readb(opaque, addr);
 369     case 2:
 370         return i6300esb_mem_readw(opaque, addr);
 371     case 4:
 372         return i6300esb_mem_readl(opaque, addr);
 373     default:
 374         g_assert_not_reached();
 375     }
 376 }
 377
 378 static void i6300esb_mem_writefn(void *opaque, hwaddr addr,
 379                                  uint64_t value, unsigned size)
 380 {
 381     switch (size) {
 382     case 1:
 383         i6300esb_mem_writeb(opaque, addr, value);
 384         break;
 385     case 2:
 386         i6300esb_mem_writew(opaque, addr, value);
 387         break;
 388     case 4:
 389         i6300esb_mem_writel(opaque, addr, value);
 390         break;
 391     default:
 392         g_assert_not_reached();
 393     }
 394 }
 395
 396 static const MemoryRegionOps i6300esb_ops = {
 397     .read = i6300esb_mem_readfn,
 398     .write = i6300esb_mem_writefn,
 399     .valid.min_access_size = 1,
 400     .valid.max_access_size = 4,
 401     .endianness = DEVICE_LITTLE_ENDIAN,
 402 };
 403
 404 static const VMStateDescription vmstate_i6300esb = {
 405     .name = "i6300esb_wdt",
 406     /* With this VMSD's introduction, version_id/minimum_version_id were
 407      * erroneously set to sizeof(I6300State), causing a somewhat random
 408      * version_id to be set for every build. This eventually broke
 409      * migration.
 410      *
 411      * To correct this without breaking old->new migration for older
 412      * versions of QEMU, we've set version_id to a value high enough
 413      * to exceed all past values of sizeof(I6300State) across various
 414      * build environments, and have reset minimum_version_id to 1,
 415      * since this VMSD has never changed and thus can accept all past
 416      * versions.
 417      *
 418      * For future changes we can treat these values as we normally would.
 419      */
 420     .version_id = 10000,
 421     .minimum_version_id = 1,
 422     .fields = (VMStateField[]) {
 423         VMSTATE_PCI_DEVICE(dev, I6300State),
 424         VMSTATE_INT32(reboot_enabled, I6300State),
 425         VMSTATE_INT32(clock_scale, I6300State),
 426         VMSTATE_INT32(int_type, I6300State),
 427         VMSTATE_INT32(free_run, I6300State),
 428         VMSTATE_INT32(locked, I6300State),
 429         VMSTATE_INT32(enabled, I6300State),
 430         VMSTATE_TIMER_PTR(timer, I6300State),
 431         VMSTATE_UINT32(timer1_preload, I6300State),
 432         VMSTATE_UINT32(timer2_preload, I6300State),
 433         VMSTATE_INT32(stage, I6300State),
 434         VMSTATE_INT32(unlock_state, I6300State),
 435         VMSTATE_INT32(previous_reboot_flag, I6300State),
 436         VMSTATE_END_OF_LIST()
 437     }
 438 };
 439
 440 static void i6300esb_realize(PCIDevice *dev, Error **errp)
 441 {
 442     I6300State *d = WATCHDOG_I6300ESB_DEVICE(dev);
 443
 444     i6300esb_debug("I6300State = %p\n", d);
 445
 446     d->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, i6300esb_timer_expired, d);
 447     d->previous_reboot_flag = 0;
 448
 449     memory_region_init_io(&d->io_mem, OBJECT(d), &i6300esb_ops, d,
 450                           "i6300esb", 0x10);
 451     pci_register_bar(&d->dev, 0, 0, &d->io_mem);
 452 }
 453
 454 static void i6300esb_exit(PCIDevice *dev)
 455 {
 456     I6300State *d = WATCHDOG_I6300ESB_DEVICE(dev);
 457
 458     timer_del(d->timer);
 459     timer_free(d->timer);
 460 }
 461
 462 static WatchdogTimerModel model = {
 463     .wdt_name = "i6300esb",
 464     .wdt_description = "Intel 6300ESB",
 465 };
 466
 467 static void i6300esb_class_init(ObjectClass *klass, void *data)
 468 {
 469     DeviceClass *dc = DEVICE_CLASS(klass);
 470     PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
 471
 472     k->config_read = i6300esb_config_read;
 473     k->config_write = i6300esb_config_write;
 474     k->realize = i6300esb_realize;
 475     k->exit = i6300esb_exit;
 476     k->vendor_id = PCI_VENDOR_ID_INTEL;
 477     k->device_id = PCI_DEVICE_ID_INTEL_ESB_9;
 478     k->class_id = PCI_CLASS_SYSTEM_OTHER;
 479     dc->reset = i6300esb_reset;
 480     dc->vmsd = &vmstate_i6300esb;
 481     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
 482 }
 483
 484 static const TypeInfo i6300esb_info = {
 485     .name          = TYPE_WATCHDOG_I6300ESB_DEVICE,
 486     .parent        = TYPE_PCI_DEVICE,
 487     .instance_size = sizeof(I6300State),
 488     .class_init    = i6300esb_class_init,
 489     .interfaces = (InterfaceInfo[]) {
 490         { INTERFACE_CONVENTIONAL_PCI_DEVICE },
 491         { },
 492     },
 493 };
 494
 495 static void i6300esb_register_types(void)
 496 {
 497     watchdog_add_model(&model);
 498     type_register_static(&i6300esb_info);
 499 }
 500
 501 type_init(i6300esb_register_types)