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