arch/x86/kernel/hpet.c

   1 #include <linux/clocksource.h>
   2 #include <linux/clockchips.h>
   3 #include <linux/interrupt.h>
   4 #include <linux/sysdev.h>
   5 #include <linux/delay.h>
   6 #include <linux/errno.h>
   7 #include <linux/slab.h>
   8 #include <linux/hpet.h>
   9 #include <linux/init.h>
  10 #include <linux/cpu.h>
  11 #include <linux/pm.h>
  12 #include <linux/io.h>
  13
  14 #include <asm/fixmap.h>
  15 #include <asm/i8253.h>
  16 #include <asm/hpet.h>
  17
  18 #define HPET_MASK                       CLOCKSOURCE_MASK(32)
  19
  20 /* FSEC = 10^-15
  21    NSEC = 10^-9 */
  22 #define FSEC_PER_NSEC                   1000000L
  23
  24 #define HPET_DEV_USED_BIT               2
  25 #define HPET_DEV_USED                   (1 << HPET_DEV_USED_BIT)
  26 #define HPET_DEV_VALID                  0x8
  27 #define HPET_DEV_FSB_CAP                0x1000
  28 #define HPET_DEV_PERI_CAP               0x2000
  29
  30 #define HPET_MIN_CYCLES                 128
  31 #define HPET_MIN_PROG_DELTA             (HPET_MIN_CYCLES + (HPET_MIN_CYCLES >> 1))
  32
  33 #define EVT_TO_HPET_DEV(evt) container_of(evt, struct hpet_dev, evt)
  34
  35 /*
  36  * HPET address is set in acpi/boot.c, when an ACPI entry exists
  37  */
  38 unsigned long                           hpet_address;
  39 u8                                      hpet_blockid; /* OS timer block num */
  40 u8                                      hpet_msi_disable;
  41
  42 #ifdef CONFIG_PCI_MSI
  43 static unsigned long                    hpet_num_timers;
  44 #endif
  45 static void __iomem                     *hpet_virt_address;
  46
  47 struct hpet_dev {
  48         struct clock_event_device       evt;
  49         unsigned int                    num;
  50         int                             cpu;
  51         unsigned int                    irq;
  52         unsigned int                    flags;
  53         char                            name[10];
  54 };
  55
  56 inline unsigned int hpet_readl(unsigned int a)
  57 {
  58         return readl(hpet_virt_address + a);
  59 }
  60
  61 static inline void hpet_writel(unsigned int d, unsigned int a)
  62 {
  63         writel(d, hpet_virt_address + a);
  64 }
  65
  66 #ifdef CONFIG_X86_64
  67 #include <asm/pgtable.h>
  68 #endif
  69
  70 static inline void hpet_set_mapping(void)
  71 {
  72         hpet_virt_address = ioremap_nocache(hpet_address, HPET_MMAP_SIZE);
  73 #ifdef CONFIG_X86_64
  74         __set_fixmap(VSYSCALL_HPET, hpet_address, PAGE_KERNEL_VVAR_NOCACHE);
  75 #endif
  76 }
  77
  78 static inline void hpet_clear_mapping(void)
  79 {
  80         iounmap(hpet_virt_address);
  81         hpet_virt_address = NULL;
  82 }
  83
  84 /*
  85  * HPET command line enable / disable
  86  */
  87 static int boot_hpet_disable;
  88 int hpet_force_user;
  89 static int hpet_verbose;
  90
  91 static int __init hpet_setup(char *str)
  92 {
  93         if (str) {
  94                 if (!strncmp("disable", str, 7))
  95                         boot_hpet_disable = 1;
  96                 if (!strncmp("force", str, 5))
  97                         hpet_force_user = 1;
  98                 if (!strncmp("verbose", str, 7))
  99                         hpet_verbose = 1;
 100         }
 101         return 1;
 102 }
 103 __setup("hpet=", hpet_setup);
 104
 105 static int __init disable_hpet(char *str)
 106 {
 107         boot_hpet_disable = 1;
 108         return 1;
 109 }
 110 __setup("nohpet", disable_hpet);
 111
 112 static inline int is_hpet_capable(void)
 113 {
 114         return !boot_hpet_disable && hpet_address;
 115 }
 116
 117 /*
 118  * HPET timer interrupt enable / disable
 119  */
 120 static int hpet_legacy_int_enabled;
 121
 122 /**
 123  * is_hpet_enabled - check whether the hpet timer interrupt is enabled
 124  */
 125 int is_hpet_enabled(void)
 126 {
 127         return is_hpet_capable() && hpet_legacy_int_enabled;
 128 }
 129 EXPORT_SYMBOL_GPL(is_hpet_enabled);
 130
 131 static void _hpet_print_config(const char *function, int line)
 132 {
 133         u32 i, timers, l, h;
 134         printk(KERN_INFO "hpet: %s(%d):\n", function, line);
 135         l = hpet_readl(HPET_ID);
 136         h = hpet_readl(HPET_PERIOD);
 137         timers = ((l & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT) + 1;
 138         printk(KERN_INFO "hpet: ID: 0x%x, PERIOD: 0x%x\n", l, h);
 139         l = hpet_readl(HPET_CFG);
 140         h = hpet_readl(HPET_STATUS);
 141         printk(KERN_INFO "hpet: CFG: 0x%x, STATUS: 0x%x\n", l, h);
 142         l = hpet_readl(HPET_COUNTER);
 143         h = hpet_readl(HPET_COUNTER+4);
 144         printk(KERN_INFO "hpet: COUNTER_l: 0x%x, COUNTER_h: 0x%x\n", l, h);
 145
 146         for (i = 0; i < timers; i++) {
 147                 l = hpet_readl(HPET_Tn_CFG(i));
 148                 h = hpet_readl(HPET_Tn_CFG(i)+4);
 149                 printk(KERN_INFO "hpet: T%d: CFG_l: 0x%x, CFG_h: 0x%x\n",
 150                        i, l, h);
 151                 l = hpet_readl(HPET_Tn_CMP(i));
 152                 h = hpet_readl(HPET_Tn_CMP(i)+4);
 153                 printk(KERN_INFO "hpet: T%d: CMP_l: 0x%x, CMP_h: 0x%x\n",
 154                        i, l, h);
 155                 l = hpet_readl(HPET_Tn_ROUTE(i));
 156                 h = hpet_readl(HPET_Tn_ROUTE(i)+4);
 157                 printk(KERN_INFO "hpet: T%d ROUTE_l: 0x%x, ROUTE_h: 0x%x\n",
 158                        i, l, h);
 159         }
 160 }
 161
 162 #define hpet_print_config()                                     \
 163 do {                                                            \
 164         if (hpet_verbose)                                       \
 165                 _hpet_print_config(__FUNCTION__, __LINE__);     \
 166 } while (0)
 167
 168 /*
 169  * When the hpet driver (/dev/hpet) is enabled, we need to reserve
 170  * timer 0 and timer 1 in case of RTC emulation.
 171  */
 172 #ifdef CONFIG_HPET
 173
 174 static void hpet_reserve_msi_timers(struct hpet_data *hd);
 175
 176 static void hpet_reserve_platform_timers(unsigned int id)
 177 {
 178         struct hpet __iomem *hpet = hpet_virt_address;
 179         struct hpet_timer __iomem *timer = &hpet->hpet_timers[2];
 180         unsigned int nrtimers, i;
 181         struct hpet_data hd;
 182
 183         nrtimers = ((id & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT) + 1;
 184
 185         memset(&hd, 0, sizeof(hd));
 186         hd.hd_phys_address      = hpet_address;
 187         hd.hd_address           = hpet;
 188         hd.hd_nirqs             = nrtimers;
 189         hpet_reserve_timer(&hd, 0);
 190
 191 #ifdef CONFIG_HPET_EMULATE_RTC
 192         hpet_reserve_timer(&hd, 1);
 193 #endif
 194
 195         /*
 196          * NOTE that hd_irq[] reflects IOAPIC input pins (LEGACY_8254
 197          * is wrong for i8259!) not the output IRQ.  Many BIOS writers
 198          * don't bother configuring *any* comparator interrupts.
 199          */
 200         hd.hd_irq[0] = HPET_LEGACY_8254;
 201         hd.hd_irq[1] = HPET_LEGACY_RTC;
 202
 203         for (i = 2; i < nrtimers; timer++, i++) {
 204                 hd.hd_irq[i] = (readl(&timer->hpet_config) &
 205                         Tn_INT_ROUTE_CNF_MASK) >> Tn_INT_ROUTE_CNF_SHIFT;
 206         }
 207
 208         hpet_reserve_msi_timers(&hd);
 209
 210         hpet_alloc(&hd);
 211
 212 }
 213 #else
 214 static void hpet_reserve_platform_timers(unsigned int id) { }
 215 #endif
 216
 217 /*
 218  * Common hpet info
 219  */
 220 static unsigned long hpet_freq;
 221
 222 static void hpet_legacy_set_mode(enum clock_event_mode mode,
 223                           struct clock_event_device *evt);
 224 static int hpet_legacy_next_event(unsigned long delta,
 225                            struct clock_event_device *evt);
 226
 227 /*
 228  * The hpet clock event device
 229  */
 230 static struct clock_event_device hpet_clockevent = {
 231         .name           = "hpet",
 232         .features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
 233         .set_mode       = hpet_legacy_set_mode,
 234         .set_next_event = hpet_legacy_next_event,
 235         .irq            = 0,
 236         .rating         = 50,
 237 };
 238
 239 static void hpet_stop_counter(void)
 240 {
 241         unsigned long cfg = hpet_readl(HPET_CFG);
 242         cfg &= ~HPET_CFG_ENABLE;
 243         hpet_writel(cfg, HPET_CFG);
 244 }
 245
 246 static void hpet_reset_counter(void)
 247 {
 248         hpet_writel(0, HPET_COUNTER);
 249         hpet_writel(0, HPET_COUNTER + 4);
 250 }
 251
 252 static void hpet_start_counter(void)
 253 {
 254         unsigned int cfg = hpet_readl(HPET_CFG);
 255         cfg |= HPET_CFG_ENABLE;
 256         hpet_writel(cfg, HPET_CFG);
 257 }
 258
 259 static void hpet_restart_counter(void)
 260 {
 261         hpet_stop_counter();
 262         hpet_reset_counter();
 263         hpet_start_counter();
 264 }
 265
 266 static void hpet_resume_device(void)
 267 {
 268         force_hpet_resume();
 269 }
 270
 271 static void hpet_resume_counter(struct clocksource *cs)
 272 {
 273         hpet_resume_device();
 274         hpet_restart_counter();
 275 }
 276
 277 static void hpet_enable_legacy_int(void)
 278 {
 279         unsigned int cfg = hpet_readl(HPET_CFG);
 280
 281         cfg |= HPET_CFG_LEGACY;
 282         hpet_writel(cfg, HPET_CFG);
 283         hpet_legacy_int_enabled = 1;
 284 }
 285
 286 static void hpet_legacy_clockevent_register(void)
 287 {
 288         /* Start HPET legacy interrupts */
 289         hpet_enable_legacy_int();
 290
 291         /*
 292          * Start hpet with the boot cpu mask and make it
 293          * global after the IO_APIC has been initialized.
 294          */
 295         hpet_clockevent.cpumask = cpumask_of(smp_processor_id());
 296         clockevents_config_and_register(&hpet_clockevent, hpet_freq,
 297                                         HPET_MIN_PROG_DELTA, 0x7FFFFFFF);
 298         global_clock_event = &hpet_clockevent;
 299         printk(KERN_DEBUG "hpet clockevent registered\n");
 300 }
 301
 302 static int hpet_setup_msi_irq(unsigned int irq);
 303
 304 static void hpet_set_mode(enum clock_event_mode mode,
 305                           struct clock_event_device *evt, int timer)
 306 {
 307         unsigned int cfg, cmp, now;
 308         uint64_t delta;
 309
 310         switch (mode) {
 311         case CLOCK_EVT_MODE_PERIODIC:
 312                 hpet_stop_counter();
 313                 delta = ((uint64_t)(NSEC_PER_SEC/HZ)) * evt->mult;
 314                 delta >>= evt->shift;
 315                 now = hpet_readl(HPET_COUNTER);
 316                 cmp = now + (unsigned int) delta;
 317                 cfg = hpet_readl(HPET_Tn_CFG(timer));
 318                 /* Make sure we use edge triggered interrupts */
 319                 cfg &= ~HPET_TN_LEVEL;
 320                 cfg |= HPET_TN_ENABLE | HPET_TN_PERIODIC |
 321                        HPET_TN_SETVAL | HPET_TN_32BIT;
 322                 hpet_writel(cfg, HPET_Tn_CFG(timer));
 323                 hpet_writel(cmp, HPET_Tn_CMP(timer));
 324                 udelay(1);
 325                 /*
 326                  * HPET on AMD 81xx needs a second write (with HPET_TN_SETVAL
 327                  * cleared) to T0_CMP to set the period. The HPET_TN_SETVAL
 328                  * bit is automatically cleared after the first write.
 329                  * (See AMD-8111 HyperTransport I/O Hub Data Sheet,
 330                  * Publication # 24674)
 331                  */
 332                 hpet_writel((unsigned int) delta, HPET_Tn_CMP(timer));
 333                 hpet_start_counter();
 334                 hpet_print_config();
 335                 break;
 336
 337         case CLOCK_EVT_MODE_ONESHOT:
 338                 cfg = hpet_readl(HPET_Tn_CFG(timer));
 339                 cfg &= ~HPET_TN_PERIODIC;
 340                 cfg |= HPET_TN_ENABLE | HPET_TN_32BIT;
 341                 hpet_writel(cfg, HPET_Tn_CFG(timer));
 342                 break;
 343
 344         case CLOCK_EVT_MODE_UNUSED:
 345         case CLOCK_EVT_MODE_SHUTDOWN:
 346                 cfg = hpet_readl(HPET_Tn_CFG(timer));
 347                 cfg &= ~HPET_TN_ENABLE;
 348                 hpet_writel(cfg, HPET_Tn_CFG(timer));
 349                 break;
 350
 351         case CLOCK_EVT_MODE_RESUME:
 352                 if (timer == 0) {
 353                         hpet_enable_legacy_int();
 354                 } else {
 355                         struct hpet_dev *hdev = EVT_TO_HPET_DEV(evt);
 356                         hpet_setup_msi_irq(hdev->irq);
 357                         disable_irq(hdev->irq);
 358                         irq_set_affinity(hdev->irq, cpumask_of(hdev->cpu));
 359                         enable_irq(hdev->irq);
 360                 }
 361                 hpet_print_config();
 362                 break;
 363         }
 364 }
 365
 366 static int hpet_next_event(unsigned long delta,
 367                            struct clock_event_device *evt, int timer)
 368 {
 369         u32 cnt;
 370         s32 res;
 371
 372         cnt = hpet_readl(HPET_COUNTER);
 373         cnt += (u32) delta;
 374         hpet_writel(cnt, HPET_Tn_CMP(timer));
 375
 376         /*
 377          * HPETs are a complete disaster. The compare register is
 378          * based on a equal comparison and neither provides a less
 379          * than or equal functionality (which would require to take
 380          * the wraparound into account) nor a simple count down event
 381          * mode. Further the write to the comparator register is
 382          * delayed internally up to two HPET clock cycles in certain
 383          * chipsets (ATI, ICH9,10). Some newer AMD chipsets have even
 384          * longer delays. We worked around that by reading back the
 385          * compare register, but that required another workaround for
 386          * ICH9,10 chips where the first readout after write can
 387          * return the old stale value. We already had a minimum
 388          * programming delta of 5us enforced, but a NMI or SMI hitting
 389          * between the counter readout and the comparator write can
 390          * move us behind that point easily. Now instead of reading
 391          * the compare register back several times, we make the ETIME
 392          * decision based on the following: Return ETIME if the
 393          * counter value after the write is less than HPET_MIN_CYCLES
 394          * away from the event or if the counter is already ahead of
 395          * the event. The minimum programming delta for the generic
 396          * clockevents code is set to 1.5 * HPET_MIN_CYCLES.
 397          */
 398         res = (s32)(cnt - hpet_readl(HPET_COUNTER));
 399
 400         return res < HPET_MIN_CYCLES ? -ETIME : 0;
 401 }
 402
 403 static void hpet_legacy_set_mode(enum clock_event_mode mode,
 404                         struct clock_event_device *evt)
 405 {
 406         hpet_set_mode(mode, evt, 0);
 407 }
 408
 409 static int hpet_legacy_next_event(unsigned long delta,
 410                         struct clock_event_device *evt)
 411 {
 412         return hpet_next_event(delta, evt, 0);
 413 }
 414
 415 /*
 416  * HPET MSI Support
 417  */
 418 #ifdef CONFIG_PCI_MSI
 419
 420 static DEFINE_PER_CPU(struct hpet_dev *, cpu_hpet_dev);
 421 static struct hpet_dev  *hpet_devs;
 422
 423 void hpet_msi_unmask(struct irq_data *data)
 424 {
 425         struct hpet_dev *hdev = data->handler_data;
 426         unsigned int cfg;
 427
 428         /* unmask it */
 429         cfg = hpet_readl(HPET_Tn_CFG(hdev->num));
 430         cfg |= HPET_TN_FSB;
 431         hpet_writel(cfg, HPET_Tn_CFG(hdev->num));
 432 }
 433
 434 void hpet_msi_mask(struct irq_data *data)
 435 {
 436         struct hpet_dev *hdev = data->handler_data;
 437         unsigned int cfg;
 438
 439         /* mask it */
 440         cfg = hpet_readl(HPET_Tn_CFG(hdev->num));
 441         cfg &= ~HPET_TN_FSB;
 442         hpet_writel(cfg, HPET_Tn_CFG(hdev->num));
 443 }
 444
 445 void hpet_msi_write(struct hpet_dev *hdev, struct msi_msg *msg)
 446 {
 447         hpet_writel(msg->data, HPET_Tn_ROUTE(hdev->num));
 448         hpet_writel(msg->address_lo, HPET_Tn_ROUTE(hdev->num) + 4);
 449 }
 450
 451 void hpet_msi_read(struct hpet_dev *hdev, struct msi_msg *msg)
 452 {
 453         msg->data = hpet_readl(HPET_Tn_ROUTE(hdev->num));
 454         msg->address_lo = hpet_readl(HPET_Tn_ROUTE(hdev->num) + 4);
 455         msg->address_hi = 0;
 456 }
 457
 458 static void hpet_msi_set_mode(enum clock_event_mode mode,
 459                                 struct clock_event_device *evt)
 460 {
 461         struct hpet_dev *hdev = EVT_TO_HPET_DEV(evt);
 462         hpet_set_mode(mode, evt, hdev->num);
 463 }
 464
 465 static int hpet_msi_next_event(unsigned long delta,
 466                                 struct clock_event_device *evt)
 467 {
 468         struct hpet_dev *hdev = EVT_TO_HPET_DEV(evt);
 469         return hpet_next_event(delta, evt, hdev->num);
 470 }
 471
 472 static int hpet_setup_msi_irq(unsigned int irq)
 473 {
 474         if (arch_setup_hpet_msi(irq, hpet_blockid)) {
 475                 destroy_irq(irq);
 476                 return -EINVAL;
 477         }
 478         return 0;
 479 }
 480
 481 static int hpet_assign_irq(struct hpet_dev *dev)
 482 {
 483         unsigned int irq;
 484
 485         irq = create_irq_nr(0, -1);
 486         if (!irq)
 487                 return -EINVAL;
 488
 489         irq_set_handler_data(irq, dev);
 490
 491         if (hpet_setup_msi_irq(irq))
 492                 return -EINVAL;
 493
 494         dev->irq = irq;
 495         return 0;
 496 }
 497
 498 static irqreturn_t hpet_interrupt_handler(int irq, void *data)
 499 {
 500         struct hpet_dev *dev = (struct hpet_dev *)data;
 501         struct clock_event_device *hevt = &dev->evt;
 502
 503         if (!hevt->event_handler) {
 504                 printk(KERN_INFO "Spurious HPET timer interrupt on HPET timer %d\n",
 505                                 dev->num);
 506                 return IRQ_HANDLED;
 507         }
 508
 509         hevt->event_handler(hevt);
 510         return IRQ_HANDLED;
 511 }
 512
 513 static int hpet_setup_irq(struct hpet_dev *dev)
 514 {
 515
 516         if (request_irq(dev->irq, hpet_interrupt_handler,
 517                         IRQF_TIMER | IRQF_DISABLED | IRQF_NOBALANCING,
 518                         dev->name, dev))
 519                 return -1;
 520
 521         disable_irq(dev->irq);
 522         irq_set_affinity(dev->irq, cpumask_of(dev->cpu));
 523         enable_irq(dev->irq);
 524
 525         printk(KERN_DEBUG "hpet: %s irq %d for MSI\n",
 526                          dev->name, dev->irq);
 527
 528         return 0;
 529 }
 530
 531 /* This should be called in specific @cpu */
 532 static void init_one_hpet_msi_clockevent(struct hpet_dev *hdev, int cpu)
 533 {
 534         struct clock_event_device *evt = &hdev->evt;
 535
 536         WARN_ON(cpu != smp_processor_id());
 537         if (!(hdev->flags & HPET_DEV_VALID))
 538                 return;
 539
 540         if (hpet_setup_msi_irq(hdev->irq))
 541                 return;
 542
 543         hdev->cpu = cpu;
 544         per_cpu(cpu_hpet_dev, cpu) = hdev;
 545         evt->name = hdev->name;
 546         hpet_setup_irq(hdev);
 547         evt->irq = hdev->irq;
 548
 549         evt->rating = 110;
 550         evt->features = CLOCK_EVT_FEAT_ONESHOT;
 551         if (hdev->flags & HPET_DEV_PERI_CAP)
 552                 evt->features |= CLOCK_EVT_FEAT_PERIODIC;
 553
 554         evt->set_mode = hpet_msi_set_mode;
 555         evt->set_next_event = hpet_msi_next_event;
 556         evt->cpumask = cpumask_of(hdev->cpu);
 557
 558         clockevents_config_and_register(evt, hpet_freq, HPET_MIN_PROG_DELTA,
 559                                         0x7FFFFFFF);
 560 }
 561
 562 #ifdef CONFIG_HPET
 563 /* Reserve at least one timer for userspace (/dev/hpet) */
 564 #define RESERVE_TIMERS 1
 565 #else
 566 #define RESERVE_TIMERS 0
 567 #endif
 568
 569 static void hpet_msi_capability_lookup(unsigned int start_timer)
 570 {
 571         unsigned int id;
 572         unsigned int num_timers;
 573         unsigned int num_timers_used = 0;
 574         int i;
 575
 576         if (hpet_msi_disable)
 577                 return;
 578
 579         if (boot_cpu_has(X86_FEATURE_ARAT))
 580                 return;
 581         id = hpet_readl(HPET_ID);
 582
 583         num_timers = ((id & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT);
 584         num_timers++; /* Value read out starts from 0 */
 585         hpet_print_config();
 586
 587         hpet_devs = kzalloc(sizeof(struct hpet_dev) * num_timers, GFP_KERNEL);
 588         if (!hpet_devs)
 589                 return;
 590
 591         hpet_num_timers = num_timers;
 592
 593         for (i = start_timer; i < num_timers - RESERVE_TIMERS; i++) {
 594                 struct hpet_dev *hdev = &hpet_devs[num_timers_used];
 595                 unsigned int cfg = hpet_readl(HPET_Tn_CFG(i));
 596
 597                 /* Only consider HPET timer with MSI support */
 598                 if (!(cfg & HPET_TN_FSB_CAP))
 599                         continue;
 600
 601                 hdev->flags = 0;
 602                 if (cfg & HPET_TN_PERIODIC_CAP)
 603                         hdev->flags |= HPET_DEV_PERI_CAP;
 604                 hdev->num = i;
 605
 606                 sprintf(hdev->name, "hpet%d", i);
 607                 if (hpet_assign_irq(hdev))
 608                         continue;
 609
 610                 hdev->flags |= HPET_DEV_FSB_CAP;
 611                 hdev->flags |= HPET_DEV_VALID;
 612                 num_timers_used++;
 613                 if (num_timers_used == num_possible_cpus())
 614                         break;
 615         }
 616
 617         printk(KERN_INFO "HPET: %d timers in total, %d timers will be used for per-cpu timer\n",
 618                 num_timers, num_timers_used);
 619 }
 620
 621 #ifdef CONFIG_HPET
 622 static void hpet_reserve_msi_timers(struct hpet_data *hd)
 623 {
 624         int i;
 625
 626         if (!hpet_devs)
 627                 return;
 628
 629         for (i = 0; i < hpet_num_timers; i++) {
 630                 struct hpet_dev *hdev = &hpet_devs[i];
 631
 632                 if (!(hdev->flags & HPET_DEV_VALID))
 633                         continue;
 634
 635                 hd->hd_irq[hdev->num] = hdev->irq;
 636                 hpet_reserve_timer(hd, hdev->num);
 637         }
 638 }
 639 #endif
 640
 641 static struct hpet_dev *hpet_get_unused_timer(void)
 642 {
 643         int i;
 644
 645         if (!hpet_devs)
 646                 return NULL;
 647
 648         for (i = 0; i < hpet_num_timers; i++) {
 649                 struct hpet_dev *hdev = &hpet_devs[i];
 650
 651                 if (!(hdev->flags & HPET_DEV_VALID))
 652                         continue;
 653                 if (test_and_set_bit(HPET_DEV_USED_BIT,
 654                         (unsigned long *)&hdev->flags))
 655                         continue;
 656                 return hdev;
 657         }
 658         return NULL;
 659 }
 660
 661 struct hpet_work_struct {
 662         struct delayed_work work;
 663         struct completion complete;
 664 };
 665
 666 static void hpet_work(struct work_struct *w)
 667 {
 668         struct hpet_dev *hdev;
 669         int cpu = smp_processor_id();
 670         struct hpet_work_struct *hpet_work;
 671
 672         hpet_work = container_of(w, struct hpet_work_struct, work.work);
 673
 674         hdev = hpet_get_unused_timer();
 675         if (hdev)
 676                 init_one_hpet_msi_clockevent(hdev, cpu);
 677
 678         complete(&hpet_work->complete);
 679 }
 680
 681 static int hpet_cpuhp_notify(struct notifier_block *n,
 682                 unsigned long action, void *hcpu)
 683 {
 684         unsigned long cpu = (unsigned long)hcpu;
 685         struct hpet_work_struct work;
 686         struct hpet_dev *hdev = per_cpu(cpu_hpet_dev, cpu);
 687
 688         switch (action & 0xf) {
 689         case CPU_ONLINE:
 690                 INIT_DELAYED_WORK_ONSTACK(&work.work, hpet_work);
 691                 init_completion(&work.complete);
 692                 /* FIXME: add schedule_work_on() */
 693                 schedule_delayed_work_on(cpu, &work.work, 0);
 694                 wait_for_completion(&work.complete);
 695                 destroy_timer_on_stack(&work.work.timer);
 696                 break;
 697         case CPU_DEAD:
 698                 if (hdev) {
 699                         free_irq(hdev->irq, hdev);
 700                         hdev->flags &= ~HPET_DEV_USED;
 701                         per_cpu(cpu_hpet_dev, cpu) = NULL;
 702                 }
 703                 break;
 704         }
 705         return NOTIFY_OK;
 706 }
 707 #else
 708
 709 static int hpet_setup_msi_irq(unsigned int irq)
 710 {
 711         return 0;
 712 }
 713 static void hpet_msi_capability_lookup(unsigned int start_timer)
 714 {
 715         return;
 716 }
 717
 718 #ifdef CONFIG_HPET
 719 static void hpet_reserve_msi_timers(struct hpet_data *hd)
 720 {
 721         return;
 722 }
 723 #endif
 724
 725 static int hpet_cpuhp_notify(struct notifier_block *n,
 726                 unsigned long action, void *hcpu)
 727 {
 728         return NOTIFY_OK;
 729 }
 730
 731 #endif
 732
 733 /*
 734  * Clock source related code
 735  */
 736 static cycle_t read_hpet(struct clocksource *cs)
 737 {
 738         return (cycle_t)hpet_readl(HPET_COUNTER);
 739 }
 740
 741 static struct clocksource clocksource_hpet = {
 742         .name           = "hpet",
 743         .rating         = 250,
 744         .read           = read_hpet,
 745         .mask           = HPET_MASK,
 746         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 747         .resume         = hpet_resume_counter,
 748 #ifdef CONFIG_X86_64
 749         .archdata       = { .vclock_mode = VCLOCK_HPET },
 750 #endif
 751 };
 752
 753 static int hpet_clocksource_register(void)
 754 {
 755         u64 start, now;
 756         cycle_t t1;
 757
 758         /* Start the counter */
 759         hpet_restart_counter();
 760
 761         /* Verify whether hpet counter works */
 762         t1 = hpet_readl(HPET_COUNTER);
 763         rdtscll(start);
 764
 765         /*
 766          * We don't know the TSC frequency yet, but waiting for
 767          * 200000 TSC cycles is safe:
 768          * 4 GHz == 50us
 769          * 1 GHz == 200us
 770          */
 771         do {
 772                 rep_nop();
 773                 rdtscll(now);
 774         } while ((now - start) < 200000UL);
 775
 776         if (t1 == hpet_readl(HPET_COUNTER)) {
 777                 printk(KERN_WARNING
 778                        "HPET counter not counting. HPET disabled\n");
 779                 return -ENODEV;
 780         }
 781
 782         clocksource_register_hz(&clocksource_hpet, (u32)hpet_freq);
 783         return 0;
 784 }
 785
 786 /**
 787  * hpet_enable - Try to setup the HPET timer. Returns 1 on success.
 788  */
 789 int __init hpet_enable(void)
 790 {
 791         unsigned long hpet_period;
 792         unsigned int id;
 793         u64 freq;
 794         int i;
 795
 796         if (!is_hpet_capable())
 797                 return 0;
 798
 799         hpet_set_mapping();
 800
 801         /*
 802          * Read the period and check for a sane value:
 803          */
 804         hpet_period = hpet_readl(HPET_PERIOD);
 805
 806         /*
 807          * AMD SB700 based systems with spread spectrum enabled use a
 808          * SMM based HPET emulation to provide proper frequency
 809          * setting. The SMM code is initialized with the first HPET
 810          * register access and takes some time to complete. During
 811          * this time the config register reads 0xffffffff. We check
 812          * for max. 1000 loops whether the config register reads a non
 813          * 0xffffffff value to make sure that HPET is up and running
 814          * before we go further. A counting loop is safe, as the HPET
 815          * access takes thousands of CPU cycles. On non SB700 based
 816          * machines this check is only done once and has no side
 817          * effects.
 818          */
 819         for (i = 0; hpet_readl(HPET_CFG) == 0xFFFFFFFF; i++) {
 820                 if (i == 1000) {
 821                         printk(KERN_WARNING
 822                                "HPET config register value = 0xFFFFFFFF. "
 823                                "Disabling HPET\n");
 824                         goto out_nohpet;
 825                 }
 826         }
 827
 828         if (hpet_period < HPET_MIN_PERIOD || hpet_period > HPET_MAX_PERIOD)
 829                 goto out_nohpet;
 830
 831         /*
 832          * The period is a femto seconds value. Convert it to a
 833          * frequency.
 834          */
 835         freq = FSEC_PER_SEC;
 836         do_div(freq, hpet_period);
 837         hpet_freq = freq;
 838
 839         /*
 840          * Read the HPET ID register to retrieve the IRQ routing
 841          * information and the number of channels
 842          */
 843         id = hpet_readl(HPET_ID);
 844         hpet_print_config();
 845
 846 #ifdef CONFIG_HPET_EMULATE_RTC
 847         /*
 848          * The legacy routing mode needs at least two channels, tick timer
 849          * and the rtc emulation channel.
 850          */
 851         if (!(id & HPET_ID_NUMBER))
 852                 goto out_nohpet;
 853 #endif
 854
 855         if (hpet_clocksource_register())
 856                 goto out_nohpet;
 857
 858         if (id & HPET_ID_LEGSUP) {
 859                 hpet_legacy_clockevent_register();
 860                 return 1;
 861         }
 862         return 0;
 863
 864 out_nohpet:
 865         hpet_clear_mapping();
 866         hpet_address = 0;
 867         return 0;
 868 }
 869
 870 /*
 871  * Needs to be late, as the reserve_timer code calls kalloc !
 872  *
 873  * Not a problem on i386 as hpet_enable is called from late_time_init,
 874  * but on x86_64 it is necessary !
 875  */
 876 static __init int hpet_late_init(void)
 877 {
 878         int cpu;
 879
 880         if (boot_hpet_disable)
 881                 return -ENODEV;
 882
 883         if (!hpet_address) {
 884                 if (!force_hpet_address)
 885                         return -ENODEV;
 886
 887                 hpet_address = force_hpet_address;
 888                 hpet_enable();
 889         }
 890
 891         if (!hpet_virt_address)
 892                 return -ENODEV;
 893
 894         if (hpet_readl(HPET_ID) & HPET_ID_LEGSUP)
 895                 hpet_msi_capability_lookup(2);
 896         else
 897                 hpet_msi_capability_lookup(0);
 898
 899         hpet_reserve_platform_timers(hpet_readl(HPET_ID));
 900         hpet_print_config();
 901
 902         if (hpet_msi_disable)
 903                 return 0;
 904
 905         if (boot_cpu_has(X86_FEATURE_ARAT))
 906                 return 0;
 907
 908         for_each_online_cpu(cpu) {
 909                 hpet_cpuhp_notify(NULL, CPU_ONLINE, (void *)(long)cpu);
 910         }
 911
 912         /* This notifier should be called after workqueue is ready */
 913         hotcpu_notifier(hpet_cpuhp_notify, -20);
 914
 915         return 0;
 916 }
 917 fs_initcall(hpet_late_init);
 918
 919 void hpet_disable(void)
 920 {
 921         if (is_hpet_capable() && hpet_virt_address) {
 922                 unsigned int cfg = hpet_readl(HPET_CFG);
 923
 924                 if (hpet_legacy_int_enabled) {
 925                         cfg &= ~HPET_CFG_LEGACY;
 926                         hpet_legacy_int_enabled = 0;
 927                 }
 928                 cfg &= ~HPET_CFG_ENABLE;
 929                 hpet_writel(cfg, HPET_CFG);
 930         }
 931 }
 932
 933 #ifdef CONFIG_HPET_EMULATE_RTC
 934
 935 /* HPET in LegacyReplacement Mode eats up RTC interrupt line. When, HPET
 936  * is enabled, we support RTC interrupt functionality in software.
 937  * RTC has 3 kinds of interrupts:
 938  * 1) Update Interrupt - generate an interrupt, every sec, when RTC clock
 939  *    is updated
 940  * 2) Alarm Interrupt - generate an interrupt at a specific time of day
 941  * 3) Periodic Interrupt - generate periodic interrupt, with frequencies
 942  *    2Hz-8192Hz (2Hz-64Hz for non-root user) (all freqs in powers of 2)
 943  * (1) and (2) above are implemented using polling at a frequency of
 944  * 64 Hz. The exact frequency is a tradeoff between accuracy and interrupt
 945  * overhead. (DEFAULT_RTC_INT_FREQ)
 946  * For (3), we use interrupts at 64Hz or user specified periodic
 947  * frequency, whichever is higher.
 948  */
 949 #include <linux/mc146818rtc.h>
 950 #include <linux/rtc.h>
 951 #include <asm/rtc.h>
 952
 953 #define DEFAULT_RTC_INT_FREQ    64
 954 #define DEFAULT_RTC_SHIFT       6
 955 #define RTC_NUM_INTS            1
 956
 957 static unsigned long hpet_rtc_flags;
 958 static int hpet_prev_update_sec;
 959 static struct rtc_time hpet_alarm_time;
 960 static unsigned long hpet_pie_count;
 961 static u32 hpet_t1_cmp;
 962 static u32 hpet_default_delta;
 963 static u32 hpet_pie_delta;
 964 static unsigned long hpet_pie_limit;
 965
 966 static rtc_irq_handler irq_handler;
 967
 968 /*
 969  * Check that the hpet counter c1 is ahead of the c2
 970  */
 971 static inline int hpet_cnt_ahead(u32 c1, u32 c2)
 972 {
 973         return (s32)(c2 - c1) < 0;
 974 }
 975
 976 /*
 977  * Registers a IRQ handler.
 978  */
 979 int hpet_register_irq_handler(rtc_irq_handler handler)
 980 {
 981         if (!is_hpet_enabled())
 982                 return -ENODEV;
 983         if (irq_handler)
 984                 return -EBUSY;
 985
 986         irq_handler = handler;
 987
 988         return 0;
 989 }
 990 EXPORT_SYMBOL_GPL(hpet_register_irq_handler);
 991
 992 /*
 993  * Deregisters the IRQ handler registered with hpet_register_irq_handler()
 994  * and does cleanup.
 995  */
 996 void hpet_unregister_irq_handler(rtc_irq_handler handler)
 997 {
 998         if (!is_hpet_enabled())
 999                 return;
1000
1001         irq_handler = NULL;
1002         hpet_rtc_flags = 0;
1003 }
1004 EXPORT_SYMBOL_GPL(hpet_unregister_irq_handler);
1005
1006 /*
1007  * Timer 1 for RTC emulation. We use one shot mode, as periodic mode
1008  * is not supported by all HPET implementations for timer 1.
1009  *
1010  * hpet_rtc_timer_init() is called when the rtc is initialized.
1011  */
1012 int hpet_rtc_timer_init(void)
1013 {
1014         unsigned int cfg, cnt, delta;
1015         unsigned long flags;
1016
1017         if (!is_hpet_enabled())
1018                 return 0;
1019
1020         if (!hpet_default_delta) {
1021                 uint64_t clc;
1022
1023                 clc = (uint64_t) hpet_clockevent.mult * NSEC_PER_SEC;
1024                 clc >>= hpet_clockevent.shift + DEFAULT_RTC_SHIFT;
1025                 hpet_default_delta = clc;
1026         }
1027
1028         if (!(hpet_rtc_flags & RTC_PIE) || hpet_pie_limit)
1029                 delta = hpet_default_delta;
1030         else
1031                 delta = hpet_pie_delta;
1032
1033         local_irq_save(flags);
1034
1035         cnt = delta + hpet_readl(HPET_COUNTER);
1036         hpet_writel(cnt, HPET_T1_CMP);
1037         hpet_t1_cmp = cnt;
1038
1039         cfg = hpet_readl(HPET_T1_CFG);
1040         cfg &= ~HPET_TN_PERIODIC;
1041         cfg |= HPET_TN_ENABLE | HPET_TN_32BIT;
1042         hpet_writel(cfg, HPET_T1_CFG);
1043
1044         local_irq_restore(flags);
1045
1046         return 1;
1047 }
1048 EXPORT_SYMBOL_GPL(hpet_rtc_timer_init);
1049
1050 /*
1051  * The functions below are called from rtc driver.
1052  * Return 0 if HPET is not being used.
1053  * Otherwise do the necessary changes and return 1.
1054  */
1055 int hpet_mask_rtc_irq_bit(unsigned long bit_mask)
1056 {
1057         if (!is_hpet_enabled())
1058                 return 0;
1059
1060         hpet_rtc_flags &= ~bit_mask;
1061         return 1;
1062 }
1063 EXPORT_SYMBOL_GPL(hpet_mask_rtc_irq_bit);
1064
1065 int hpet_set_rtc_irq_bit(unsigned long bit_mask)
1066 {
1067         unsigned long oldbits = hpet_rtc_flags;
1068
1069         if (!is_hpet_enabled())
1070                 return 0;
1071
1072         hpet_rtc_flags |= bit_mask;
1073
1074         if ((bit_mask & RTC_UIE) && !(oldbits & RTC_UIE))
1075                 hpet_prev_update_sec = -1;
1076
1077         if (!oldbits)
1078                 hpet_rtc_timer_init();
1079
1080         return 1;
1081 }
1082 EXPORT_SYMBOL_GPL(hpet_set_rtc_irq_bit);
1083
1084 int hpet_set_alarm_time(unsigned char hrs, unsigned char min,
1085                         unsigned char sec)
1086 {
1087         if (!is_hpet_enabled())
1088                 return 0;
1089
1090         hpet_alarm_time.tm_hour = hrs;
1091         hpet_alarm_time.tm_min = min;
1092         hpet_alarm_time.tm_sec = sec;
1093
1094         return 1;
1095 }
1096 EXPORT_SYMBOL_GPL(hpet_set_alarm_time);
1097
1098 int hpet_set_periodic_freq(unsigned long freq)
1099 {
1100         uint64_t clc;
1101
1102         if (!is_hpet_enabled())
1103                 return 0;
1104
1105         if (freq <= DEFAULT_RTC_INT_FREQ)
1106                 hpet_pie_limit = DEFAULT_RTC_INT_FREQ / freq;
1107         else {
1108                 clc = (uint64_t) hpet_clockevent.mult * NSEC_PER_SEC;
1109                 do_div(clc, freq);
1110                 clc >>= hpet_clockevent.shift;
1111                 hpet_pie_delta = clc;
1112                 hpet_pie_limit = 0;
1113         }
1114         return 1;
1115 }
1116 EXPORT_SYMBOL_GPL(hpet_set_periodic_freq);
1117
1118 int hpet_rtc_dropped_irq(void)
1119 {
1120         return is_hpet_enabled();
1121 }
1122 EXPORT_SYMBOL_GPL(hpet_rtc_dropped_irq);
1123
1124 static void hpet_rtc_timer_reinit(void)
1125 {
1126         unsigned int cfg, delta;
1127         int lost_ints = -1;
1128
1129         if (unlikely(!hpet_rtc_flags)) {
1130                 cfg = hpet_readl(HPET_T1_CFG);
1131                 cfg &= ~HPET_TN_ENABLE;
1132                 hpet_writel(cfg, HPET_T1_CFG);
1133                 return;
1134         }
1135
1136         if (!(hpet_rtc_flags & RTC_PIE) || hpet_pie_limit)
1137                 delta = hpet_default_delta;
1138         else
1139                 delta = hpet_pie_delta;
1140
1141         /*
1142          * Increment the comparator value until we are ahead of the
1143          * current count.
1144          */
1145         do {
1146                 hpet_t1_cmp += delta;
1147                 hpet_writel(hpet_t1_cmp, HPET_T1_CMP);
1148                 lost_ints++;
1149         } while (!hpet_cnt_ahead(hpet_t1_cmp, hpet_readl(HPET_COUNTER)));
1150
1151         if (lost_ints) {
1152                 if (hpet_rtc_flags & RTC_PIE)
1153                         hpet_pie_count += lost_ints;
1154                 if (printk_ratelimit())
1155                         printk(KERN_WARNING "hpet1: lost %d rtc interrupts\n",
1156                                 lost_ints);
1157         }
1158 }
1159
1160 irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id)
1161 {
1162         struct rtc_time curr_time;
1163         unsigned long rtc_int_flag = 0;
1164
1165         hpet_rtc_timer_reinit();
1166         memset(&curr_time, 0, sizeof(struct rtc_time));
1167
1168         if (hpet_rtc_flags & (RTC_UIE | RTC_AIE))
1169                 get_rtc_time(&curr_time);
1170
1171         if (hpet_rtc_flags & RTC_UIE &&
1172             curr_time.tm_sec != hpet_prev_update_sec) {
1173                 if (hpet_prev_update_sec >= 0)
1174                         rtc_int_flag = RTC_UF;
1175                 hpet_prev_update_sec = curr_time.tm_sec;
1176         }
1177
1178         if (hpet_rtc_flags & RTC_PIE &&
1179             ++hpet_pie_count >= hpet_pie_limit) {
1180                 rtc_int_flag |= RTC_PF;
1181                 hpet_pie_count = 0;
1182         }
1183
1184         if (hpet_rtc_flags & RTC_AIE &&
1185             (curr_time.tm_sec == hpet_alarm_time.tm_sec) &&
1186             (curr_time.tm_min == hpet_alarm_time.tm_min) &&
1187             (curr_time.tm_hour == hpet_alarm_time.tm_hour))
1188                         rtc_int_flag |= RTC_AF;
1189
1190         if (rtc_int_flag) {
1191                 rtc_int_flag |= (RTC_IRQF | (RTC_NUM_INTS << 8));
1192                 if (irq_handler)
1193                         irq_handler(rtc_int_flag, dev_id);
1194         }
1195         return IRQ_HANDLED;
1196 }
1197 EXPORT_SYMBOL_GPL(hpet_rtc_interrupt);
1198 #endif