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/hpet.h>
   8 #include <linux/init.h>
   9 #include <linux/cpu.h>
  10 #include <linux/pm.h>
  11 #include <linux/io.h>
  12
  13 #include <asm/fixmap.h>
  14 #include <asm/i8253.h>
  15 #include <asm/hpet.h>
  16
  17 #define HPET_MASK                       CLOCKSOURCE_MASK(32)
  18 #define HPET_SHIFT                      22
  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 EVT_TO_HPET_DEV(evt) container_of(evt, struct hpet_dev, evt)
  31
  32 /*
  33  * HPET address is set in acpi/boot.c, when an ACPI entry exists
  34  */
  35 unsigned long                           hpet_address;
  36 u8                                      hpet_blockid; /* OS timer block num */
  37 u8                                      hpet_msi_disable;
  38
  39 #ifdef CONFIG_PCI_MSI
  40 static unsigned long                    hpet_num_timers;
  41 #endif
  42 static void __iomem                     *hpet_virt_address;
  43
  44 struct hpet_dev {
  45         struct clock_event_device       evt;
  46         unsigned int                    num;
  47         int                             cpu;
  48         unsigned int                    irq;
  49         unsigned int                    flags;
  50         char                            name[10];
  51 };
  52
  53 inline unsigned int hpet_readl(unsigned int a)
  54 {
  55         return readl(hpet_virt_address + a);
  56 }
  57
  58 static inline void hpet_writel(unsigned int d, unsigned int a)
  59 {
  60         writel(d, hpet_virt_address + a);
  61 }
  62
  63 #ifdef CONFIG_X86_64
  64 #include <asm/pgtable.h>
  65 #endif
  66
  67 static inline void hpet_set_mapping(void)
  68 {
  69         hpet_virt_address = ioremap_nocache(hpet_address, HPET_MMAP_SIZE);
  70 #ifdef CONFIG_X86_64
  71         __set_fixmap(VSYSCALL_HPET, hpet_address, PAGE_KERNEL_VSYSCALL_NOCACHE);
  72 #endif
  73 }
  74
  75 static inline void hpet_clear_mapping(void)
  76 {
  77         iounmap(hpet_virt_address);
  78         hpet_virt_address = NULL;
  79 }
  80
  81 /*
  82  * HPET command line enable / disable
  83  */
  84 static int boot_hpet_disable;
  85 int hpet_force_user;
  86 static int hpet_verbose;
  87
  88 static int __init hpet_setup(char *str)
  89 {
  90         if (str) {
  91                 if (!strncmp("disable", str, 7))
  92                         boot_hpet_disable = 1;
  93                 if (!strncmp("force", str, 5))
  94                         hpet_force_user = 1;
  95                 if (!strncmp("verbose", str, 7))
  96                         hpet_verbose = 1;
  97         }
  98         return 1;
  99 }
 100 __setup("hpet=", hpet_setup);
 101
 102 static int __init disable_hpet(char *str)
 103 {
 104         boot_hpet_disable = 1;
 105         return 1;
 106 }
 107 __setup("nohpet", disable_hpet);
 108
 109 static inline int is_hpet_capable(void)
 110 {
 111         return !boot_hpet_disable && hpet_address;
 112 }
 113
 114 /*
 115  * HPET timer interrupt enable / disable
 116  */
 117 static int hpet_legacy_int_enabled;
 118
 119 /**
 120  * is_hpet_enabled - check whether the hpet timer interrupt is enabled
 121  */
 122 int is_hpet_enabled(void)
 123 {
 124         return is_hpet_capable() && hpet_legacy_int_enabled;
 125 }
 126 EXPORT_SYMBOL_GPL(is_hpet_enabled);
 127
 128 static void _hpet_print_config(const char *function, int line)
 129 {
 130         u32 i, timers, l, h;
 131         printk(KERN_INFO "hpet: %s(%d):\n", function, line);
 132         l = hpet_readl(HPET_ID);
 133         h = hpet_readl(HPET_PERIOD);
 134         timers = ((l & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT) + 1;
 135         printk(KERN_INFO "hpet: ID: 0x%x, PERIOD: 0x%x\n", l, h);
 136         l = hpet_readl(HPET_CFG);
 137         h = hpet_readl(HPET_STATUS);
 138         printk(KERN_INFO "hpet: CFG: 0x%x, STATUS: 0x%x\n", l, h);
 139         l = hpet_readl(HPET_COUNTER);
 140         h = hpet_readl(HPET_COUNTER+4);
 141         printk(KERN_INFO "hpet: COUNTER_l: 0x%x, COUNTER_h: 0x%x\n", l, h);
 142
 143         for (i = 0; i < timers; i++) {
 144                 l = hpet_readl(HPET_Tn_CFG(i));
 145                 h = hpet_readl(HPET_Tn_CFG(i)+4);
 146                 printk(KERN_INFO "hpet: T%d: CFG_l: 0x%x, CFG_h: 0x%x\n",
 147                        i, l, h);
 148                 l = hpet_readl(HPET_Tn_CMP(i));
 149                 h = hpet_readl(HPET_Tn_CMP(i)+4);
 150                 printk(KERN_INFO "hpet: T%d: CMP_l: 0x%x, CMP_h: 0x%x\n",
 151                        i, l, h);
 152                 l = hpet_readl(HPET_Tn_ROUTE(i));
 153                 h = hpet_readl(HPET_Tn_ROUTE(i)+4);
 154                 printk(KERN_INFO "hpet: T%d ROUTE_l: 0x%x, ROUTE_h: 0x%x\n",
 155                        i, l, h);
 156         }
 157 }
 158
 159 #define hpet_print_config()                                     \
 160 do {                                                            \
 161         if (hpet_verbose)                                       \
 162                 _hpet_print_config(__FUNCTION__, __LINE__);     \
 163 } while (0)
 164
 165 /*
 166  * When the hpet driver (/dev/hpet) is enabled, we need to reserve
 167  * timer 0 and timer 1 in case of RTC emulation.
 168  */
 169 #ifdef CONFIG_HPET
 170
 171 static void hpet_reserve_msi_timers(struct hpet_data *hd);
 172
 173 static void hpet_reserve_platform_timers(unsigned int id)
 174 {
 175         struct hpet __iomem *hpet = hpet_virt_address;
 176         struct hpet_timer __iomem *timer = &hpet->hpet_timers[2];
 177         unsigned int nrtimers, i;
 178         struct hpet_data hd;
 179
 180         nrtimers = ((id & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT) + 1;
 181
 182         memset(&hd, 0, sizeof(hd));
 183         hd.hd_phys_address      = hpet_address;
 184         hd.hd_address           = hpet;
 185         hd.hd_nirqs             = nrtimers;
 186         hpet_reserve_timer(&hd, 0);
 187
 188 #ifdef CONFIG_HPET_EMULATE_RTC
 189         hpet_reserve_timer(&hd, 1);
 190 #endif
 191
 192         /*
 193          * NOTE that hd_irq[] reflects IOAPIC input pins (LEGACY_8254
 194          * is wrong for i8259!) not the output IRQ.  Many BIOS writers
 195          * don't bother configuring *any* comparator interrupts.
 196          */
 197         hd.hd_irq[0] = HPET_LEGACY_8254;
 198         hd.hd_irq[1] = HPET_LEGACY_RTC;
 199
 200         for (i = 2; i < nrtimers; timer++, i++) {
 201                 hd.hd_irq[i] = (readl(&timer->hpet_config) &
 202                         Tn_INT_ROUTE_CNF_MASK) >> Tn_INT_ROUTE_CNF_SHIFT;
 203         }
 204
 205         hpet_reserve_msi_timers(&hd);
 206
 207         hpet_alloc(&hd);
 208
 209 }
 210 #else
 211 static void hpet_reserve_platform_timers(unsigned int id) { }
 212 #endif
 213
 214 /*
 215  * Common hpet info
 216  */
 217 static unsigned long hpet_period;
 218
 219 static void hpet_legacy_set_mode(enum clock_event_mode mode,
 220                           struct clock_event_device *evt);
 221 static int hpet_legacy_next_event(unsigned long delta,
 222                            struct clock_event_device *evt);
 223
 224 /*
 225  * The hpet clock event device
 226  */
 227 static struct clock_event_device hpet_clockevent = {
 228         .name           = "hpet",
 229         .features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
 230         .set_mode       = hpet_legacy_set_mode,
 231         .set_next_event = hpet_legacy_next_event,
 232         .shift          = 32,
 233         .irq            = 0,
 234         .rating         = 50,
 235 };
 236
 237 static void hpet_stop_counter(void)
 238 {
 239         unsigned long cfg = hpet_readl(HPET_CFG);
 240         cfg &= ~HPET_CFG_ENABLE;
 241         hpet_writel(cfg, HPET_CFG);
 242 }
 243
 244 static void hpet_reset_counter(void)
 245 {
 246         hpet_writel(0, HPET_COUNTER);
 247         hpet_writel(0, HPET_COUNTER + 4);
 248 }
 249
 250 static void hpet_start_counter(void)
 251 {
 252         unsigned int cfg = hpet_readl(HPET_CFG);
 253         cfg |= HPET_CFG_ENABLE;
 254         hpet_writel(cfg, HPET_CFG);
 255 }
 256
 257 static void hpet_restart_counter(void)
 258 {
 259         hpet_stop_counter();
 260         hpet_reset_counter();
 261         hpet_start_counter();
 262 }
 263
 264 static void hpet_resume_device(void)
 265 {
 266         force_hpet_resume();
 267 }
 268
 269 static void hpet_resume_counter(void)
 270 {
 271         hpet_resume_device();
 272         hpet_restart_counter();
 273 }
 274
 275 static void hpet_enable_legacy_int(void)
 276 {
 277         unsigned int cfg = hpet_readl(HPET_CFG);
 278
 279         cfg |= HPET_CFG_LEGACY;
 280         hpet_writel(cfg, HPET_CFG);
 281         hpet_legacy_int_enabled = 1;
 282 }
 283
 284 static void hpet_legacy_clockevent_register(void)
 285 {
 286         /* Start HPET legacy interrupts */
 287         hpet_enable_legacy_int();
 288
 289         /*
 290          * The mult factor is defined as (include/linux/clockchips.h)
 291          *  mult/2^shift = cyc/ns (in contrast to ns/cyc in clocksource.h)
 292          * hpet_period is in units of femtoseconds (per cycle), so
 293          *  mult/2^shift = cyc/ns = 10^6/hpet_period
 294          *  mult = (10^6 * 2^shift)/hpet_period
 295          *  mult = (FSEC_PER_NSEC << hpet_clockevent.shift)/hpet_period
 296          */
 297         hpet_clockevent.mult = div_sc((unsigned long) FSEC_PER_NSEC,
 298                                       hpet_period, hpet_clockevent.shift);
 299         /* Calculate the min / max delta */
 300         hpet_clockevent.max_delta_ns = clockevent_delta2ns(0x7FFFFFFF,
 301                                                            &hpet_clockevent);
 302         /* 5 usec minimum reprogramming delta. */
 303         hpet_clockevent.min_delta_ns = 5000;
 304
 305         /*
 306          * Start hpet with the boot cpu mask and make it
 307          * global after the IO_APIC has been initialized.
 308          */
 309         hpet_clockevent.cpumask = cpumask_of(smp_processor_id());
 310         clockevents_register_device(&hpet_clockevent);
 311         global_clock_event = &hpet_clockevent;
 312         printk(KERN_DEBUG "hpet clockevent registered\n");
 313 }
 314
 315 static int hpet_setup_msi_irq(unsigned int irq);
 316
 317 static void hpet_set_mode(enum clock_event_mode mode,
 318                           struct clock_event_device *evt, int timer)
 319 {
 320         unsigned int cfg, cmp, now;
 321         uint64_t delta;
 322
 323         switch (mode) {
 324         case CLOCK_EVT_MODE_PERIODIC:
 325                 hpet_stop_counter();
 326                 delta = ((uint64_t)(NSEC_PER_SEC/HZ)) * evt->mult;
 327                 delta >>= evt->shift;
 328                 now = hpet_readl(HPET_COUNTER);
 329                 cmp = now + (unsigned int) delta;
 330                 cfg = hpet_readl(HPET_Tn_CFG(timer));
 331                 /* Make sure we use edge triggered interrupts */
 332                 cfg &= ~HPET_TN_LEVEL;
 333                 cfg |= HPET_TN_ENABLE | HPET_TN_PERIODIC |
 334                        HPET_TN_SETVAL | HPET_TN_32BIT;
 335                 hpet_writel(cfg, HPET_Tn_CFG(timer));
 336                 hpet_writel(cmp, HPET_Tn_CMP(timer));
 337                 udelay(1);
 338                 /*
 339                  * HPET on AMD 81xx needs a second write (with HPET_TN_SETVAL
 340                  * cleared) to T0_CMP to set the period. The HPET_TN_SETVAL
 341                  * bit is automatically cleared after the first write.
 342                  * (See AMD-8111 HyperTransport I/O Hub Data Sheet,
 343                  * Publication # 24674)
 344                  */
 345                 hpet_writel((unsigned int) delta, HPET_Tn_CMP(timer));
 346                 hpet_start_counter();
 347                 hpet_print_config();
 348                 break;
 349
 350         case CLOCK_EVT_MODE_ONESHOT:
 351                 cfg = hpet_readl(HPET_Tn_CFG(timer));
 352                 cfg &= ~HPET_TN_PERIODIC;
 353                 cfg |= HPET_TN_ENABLE | HPET_TN_32BIT;
 354                 hpet_writel(cfg, HPET_Tn_CFG(timer));
 355                 break;
 356
 357         case CLOCK_EVT_MODE_UNUSED:
 358         case CLOCK_EVT_MODE_SHUTDOWN:
 359                 cfg = hpet_readl(HPET_Tn_CFG(timer));
 360                 cfg &= ~HPET_TN_ENABLE;
 361                 hpet_writel(cfg, HPET_Tn_CFG(timer));
 362                 break;
 363
 364         case CLOCK_EVT_MODE_RESUME:
 365                 if (timer == 0) {
 366                         hpet_enable_legacy_int();
 367                 } else {
 368                         struct hpet_dev *hdev = EVT_TO_HPET_DEV(evt);
 369                         hpet_setup_msi_irq(hdev->irq);
 370                         disable_irq(hdev->irq);
 371                         irq_set_affinity(hdev->irq, cpumask_of(hdev->cpu));
 372                         enable_irq(hdev->irq);
 373                 }
 374                 hpet_print_config();
 375                 break;
 376         }
 377 }
 378
 379 static int hpet_next_event(unsigned long delta,
 380                            struct clock_event_device *evt, int timer)
 381 {
 382         u32 cnt;
 383
 384         cnt = hpet_readl(HPET_COUNTER);
 385         cnt += (u32) delta;
 386         hpet_writel(cnt, HPET_Tn_CMP(timer));
 387
 388         /*
 389          * We need to read back the CMP register on certain HPET
 390          * implementations (ATI chipsets) which seem to delay the
 391          * transfer of the compare register into the internal compare
 392          * logic. With small deltas this might actually be too late as
 393          * the counter could already be higher than the compare value
 394          * at that point and we would wait for the next hpet interrupt
 395          * forever. We found out that reading the CMP register back
 396          * forces the transfer so we can rely on the comparison with
 397          * the counter register below. If the read back from the
 398          * compare register does not match the value we programmed
 399          * then we might have a real hardware problem. We can not do
 400          * much about it here, but at least alert the user/admin with
 401          * a prominent warning.
 402          */
 403         WARN_ONCE(hpet_readl(HPET_Tn_CMP(timer)) != cnt,
 404                   KERN_WARNING "hpet: compare register read back failed.\n");
 405
 406         return (s32)(hpet_readl(HPET_COUNTER) - cnt) >= 0 ? -ETIME : 0;
 407 }
 408
 409 static void hpet_legacy_set_mode(enum clock_event_mode mode,
 410                         struct clock_event_device *evt)
 411 {
 412         hpet_set_mode(mode, evt, 0);
 413 }
 414
 415 static int hpet_legacy_next_event(unsigned long delta,
 416                         struct clock_event_device *evt)
 417 {
 418         return hpet_next_event(delta, evt, 0);
 419 }
 420
 421 /*
 422  * HPET MSI Support
 423  */
 424 #ifdef CONFIG_PCI_MSI
 425
 426 static DEFINE_PER_CPU(struct hpet_dev *, cpu_hpet_dev);
 427 static struct hpet_dev  *hpet_devs;
 428
 429 void hpet_msi_unmask(unsigned int irq)
 430 {
 431         struct hpet_dev *hdev = get_irq_data(irq);
 432         unsigned int cfg;
 433
 434         /* unmask it */
 435         cfg = hpet_readl(HPET_Tn_CFG(hdev->num));
 436         cfg |= HPET_TN_FSB;
 437         hpet_writel(cfg, HPET_Tn_CFG(hdev->num));
 438 }
 439
 440 void hpet_msi_mask(unsigned int irq)
 441 {
 442         unsigned int cfg;
 443         struct hpet_dev *hdev = get_irq_data(irq);
 444
 445         /* mask it */
 446         cfg = hpet_readl(HPET_Tn_CFG(hdev->num));
 447         cfg &= ~HPET_TN_FSB;
 448         hpet_writel(cfg, HPET_Tn_CFG(hdev->num));
 449 }
 450
 451 void hpet_msi_write(unsigned int irq, struct msi_msg *msg)
 452 {
 453         struct hpet_dev *hdev = get_irq_data(irq);
 454
 455         hpet_writel(msg->data, HPET_Tn_ROUTE(hdev->num));
 456         hpet_writel(msg->address_lo, HPET_Tn_ROUTE(hdev->num) + 4);
 457 }
 458
 459 void hpet_msi_read(unsigned int irq, struct msi_msg *msg)
 460 {
 461         struct hpet_dev *hdev = get_irq_data(irq);
 462
 463         msg->data = hpet_readl(HPET_Tn_ROUTE(hdev->num));
 464         msg->address_lo = hpet_readl(HPET_Tn_ROUTE(hdev->num) + 4);
 465         msg->address_hi = 0;
 466 }
 467
 468 static void hpet_msi_set_mode(enum clock_event_mode mode,
 469                                 struct clock_event_device *evt)
 470 {
 471         struct hpet_dev *hdev = EVT_TO_HPET_DEV(evt);
 472         hpet_set_mode(mode, evt, hdev->num);
 473 }
 474
 475 static int hpet_msi_next_event(unsigned long delta,
 476                                 struct clock_event_device *evt)
 477 {
 478         struct hpet_dev *hdev = EVT_TO_HPET_DEV(evt);
 479         return hpet_next_event(delta, evt, hdev->num);
 480 }
 481
 482 static int hpet_setup_msi_irq(unsigned int irq)
 483 {
 484         if (arch_setup_hpet_msi(irq, hpet_blockid)) {
 485                 destroy_irq(irq);
 486                 return -EINVAL;
 487         }
 488         return 0;
 489 }
 490
 491 static int hpet_assign_irq(struct hpet_dev *dev)
 492 {
 493         unsigned int irq;
 494
 495         irq = create_irq();
 496         if (!irq)
 497                 return -EINVAL;
 498
 499         set_irq_data(irq, dev);
 500
 501         if (hpet_setup_msi_irq(irq))
 502                 return -EINVAL;
 503
 504         dev->irq = irq;
 505         return 0;
 506 }
 507
 508 static irqreturn_t hpet_interrupt_handler(int irq, void *data)
 509 {
 510         struct hpet_dev *dev = (struct hpet_dev *)data;
 511         struct clock_event_device *hevt = &dev->evt;
 512
 513         if (!hevt->event_handler) {
 514                 printk(KERN_INFO "Spurious HPET timer interrupt on HPET timer %d\n",
 515                                 dev->num);
 516                 return IRQ_HANDLED;
 517         }
 518
 519         hevt->event_handler(hevt);
 520         return IRQ_HANDLED;
 521 }
 522
 523 static int hpet_setup_irq(struct hpet_dev *dev)
 524 {
 525
 526         if (request_irq(dev->irq, hpet_interrupt_handler,
 527                         IRQF_TIMER | IRQF_DISABLED | IRQF_NOBALANCING,
 528                         dev->name, dev))
 529                 return -1;
 530
 531         disable_irq(dev->irq);
 532         irq_set_affinity(dev->irq, cpumask_of(dev->cpu));
 533         enable_irq(dev->irq);
 534
 535         printk(KERN_DEBUG "hpet: %s irq %d for MSI\n",
 536                          dev->name, dev->irq);
 537
 538         return 0;
 539 }
 540
 541 /* This should be called in specific @cpu */
 542 static void init_one_hpet_msi_clockevent(struct hpet_dev *hdev, int cpu)
 543 {
 544         struct clock_event_device *evt = &hdev->evt;
 545         uint64_t hpet_freq;
 546
 547         WARN_ON(cpu != smp_processor_id());
 548         if (!(hdev->flags & HPET_DEV_VALID))
 549                 return;
 550
 551         if (hpet_setup_msi_irq(hdev->irq))
 552                 return;
 553
 554         hdev->cpu = cpu;
 555         per_cpu(cpu_hpet_dev, cpu) = hdev;
 556         evt->name = hdev->name;
 557         hpet_setup_irq(hdev);
 558         evt->irq = hdev->irq;
 559
 560         evt->rating = 110;
 561         evt->features = CLOCK_EVT_FEAT_ONESHOT;
 562         if (hdev->flags & HPET_DEV_PERI_CAP)
 563                 evt->features |= CLOCK_EVT_FEAT_PERIODIC;
 564
 565         evt->set_mode = hpet_msi_set_mode;
 566         evt->set_next_event = hpet_msi_next_event;
 567         evt->shift = 32;
 568
 569         /*
 570          * The period is a femto seconds value. We need to calculate the
 571          * scaled math multiplication factor for nanosecond to hpet tick
 572          * conversion.
 573          */
 574         hpet_freq = 1000000000000000ULL;
 575         do_div(hpet_freq, hpet_period);
 576         evt->mult = div_sc((unsigned long) hpet_freq,
 577                                       NSEC_PER_SEC, evt->shift);
 578         /* Calculate the max delta */
 579         evt->max_delta_ns = clockevent_delta2ns(0x7FFFFFFF, evt);
 580         /* 5 usec minimum reprogramming delta. */
 581         evt->min_delta_ns = 5000;
 582
 583         evt->cpumask = cpumask_of(hdev->cpu);
 584         clockevents_register_device(evt);
 585 }
 586
 587 #ifdef CONFIG_HPET
 588 /* Reserve at least one timer for userspace (/dev/hpet) */
 589 #define RESERVE_TIMERS 1
 590 #else
 591 #define RESERVE_TIMERS 0
 592 #endif
 593
 594 static void hpet_msi_capability_lookup(unsigned int start_timer)
 595 {
 596         unsigned int id;
 597         unsigned int num_timers;
 598         unsigned int num_timers_used = 0;
 599         int i;
 600
 601         if (hpet_msi_disable)
 602                 return;
 603
 604         if (boot_cpu_has(X86_FEATURE_ARAT))
 605                 return;
 606         id = hpet_readl(HPET_ID);
 607
 608         num_timers = ((id & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT);
 609         num_timers++; /* Value read out starts from 0 */
 610         hpet_print_config();
 611
 612         hpet_devs = kzalloc(sizeof(struct hpet_dev) * num_timers, GFP_KERNEL);
 613         if (!hpet_devs)
 614                 return;
 615
 616         hpet_num_timers = num_timers;
 617
 618         for (i = start_timer; i < num_timers - RESERVE_TIMERS; i++) {
 619                 struct hpet_dev *hdev = &hpet_devs[num_timers_used];
 620                 unsigned int cfg = hpet_readl(HPET_Tn_CFG(i));
 621
 622                 /* Only consider HPET timer with MSI support */
 623                 if (!(cfg & HPET_TN_FSB_CAP))
 624                         continue;
 625
 626                 hdev->flags = 0;
 627                 if (cfg & HPET_TN_PERIODIC_CAP)
 628                         hdev->flags |= HPET_DEV_PERI_CAP;
 629                 hdev->num = i;
 630
 631                 sprintf(hdev->name, "hpet%d", i);
 632                 if (hpet_assign_irq(hdev))
 633                         continue;
 634
 635                 hdev->flags |= HPET_DEV_FSB_CAP;
 636                 hdev->flags |= HPET_DEV_VALID;
 637                 num_timers_used++;
 638                 if (num_timers_used == num_possible_cpus())
 639                         break;
 640         }
 641
 642         printk(KERN_INFO "HPET: %d timers in total, %d timers will be used for per-cpu timer\n",
 643                 num_timers, num_timers_used);
 644 }
 645
 646 #ifdef CONFIG_HPET
 647 static void hpet_reserve_msi_timers(struct hpet_data *hd)
 648 {
 649         int i;
 650
 651         if (!hpet_devs)
 652                 return;
 653
 654         for (i = 0; i < hpet_num_timers; i++) {
 655                 struct hpet_dev *hdev = &hpet_devs[i];
 656
 657                 if (!(hdev->flags & HPET_DEV_VALID))
 658                         continue;
 659
 660                 hd->hd_irq[hdev->num] = hdev->irq;
 661                 hpet_reserve_timer(hd, hdev->num);
 662         }
 663 }
 664 #endif
 665
 666 static struct hpet_dev *hpet_get_unused_timer(void)
 667 {
 668         int i;
 669
 670         if (!hpet_devs)
 671                 return NULL;
 672
 673         for (i = 0; i < hpet_num_timers; i++) {
 674                 struct hpet_dev *hdev = &hpet_devs[i];
 675
 676                 if (!(hdev->flags & HPET_DEV_VALID))
 677                         continue;
 678                 if (test_and_set_bit(HPET_DEV_USED_BIT,
 679                         (unsigned long *)&hdev->flags))
 680                         continue;
 681                 return hdev;
 682         }
 683         return NULL;
 684 }
 685
 686 struct hpet_work_struct {
 687         struct delayed_work work;
 688         struct completion complete;
 689 };
 690
 691 static void hpet_work(struct work_struct *w)
 692 {
 693         struct hpet_dev *hdev;
 694         int cpu = smp_processor_id();
 695         struct hpet_work_struct *hpet_work;
 696
 697         hpet_work = container_of(w, struct hpet_work_struct, work.work);
 698
 699         hdev = hpet_get_unused_timer();
 700         if (hdev)
 701                 init_one_hpet_msi_clockevent(hdev, cpu);
 702
 703         complete(&hpet_work->complete);
 704 }
 705
 706 static int hpet_cpuhp_notify(struct notifier_block *n,
 707                 unsigned long action, void *hcpu)
 708 {
 709         unsigned long cpu = (unsigned long)hcpu;
 710         struct hpet_work_struct work;
 711         struct hpet_dev *hdev = per_cpu(cpu_hpet_dev, cpu);
 712
 713         switch (action & 0xf) {
 714         case CPU_ONLINE:
 715                 INIT_DELAYED_WORK_ON_STACK(&work.work, hpet_work);
 716                 init_completion(&work.complete);
 717                 /* FIXME: add schedule_work_on() */
 718                 schedule_delayed_work_on(cpu, &work.work, 0);
 719                 wait_for_completion(&work.complete);
 720                 destroy_timer_on_stack(&work.work.timer);
 721                 break;
 722         case CPU_DEAD:
 723                 if (hdev) {
 724                         free_irq(hdev->irq, hdev);
 725                         hdev->flags &= ~HPET_DEV_USED;
 726                         per_cpu(cpu_hpet_dev, cpu) = NULL;
 727                 }
 728                 break;
 729         }
 730         return NOTIFY_OK;
 731 }
 732 #else
 733
 734 static int hpet_setup_msi_irq(unsigned int irq)
 735 {
 736         return 0;
 737 }
 738 static void hpet_msi_capability_lookup(unsigned int start_timer)
 739 {
 740         return;
 741 }
 742
 743 #ifdef CONFIG_HPET
 744 static void hpet_reserve_msi_timers(struct hpet_data *hd)
 745 {
 746         return;
 747 }
 748 #endif
 749
 750 static int hpet_cpuhp_notify(struct notifier_block *n,
 751                 unsigned long action, void *hcpu)
 752 {
 753         return NOTIFY_OK;
 754 }
 755
 756 #endif
 757
 758 /*
 759  * Clock source related code
 760  */
 761 static cycle_t read_hpet(struct clocksource *cs)
 762 {
 763         return (cycle_t)hpet_readl(HPET_COUNTER);
 764 }
 765
 766 #ifdef CONFIG_X86_64
 767 static cycle_t __vsyscall_fn vread_hpet(void)
 768 {
 769         return readl((const void __iomem *)fix_to_virt(VSYSCALL_HPET) + 0xf0);
 770 }
 771 #endif
 772
 773 static struct clocksource clocksource_hpet = {
 774         .name           = "hpet",
 775         .rating         = 250,
 776         .read           = read_hpet,
 777         .mask           = HPET_MASK,
 778         .shift          = HPET_SHIFT,
 779         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 780         .resume         = hpet_resume_counter,
 781 #ifdef CONFIG_X86_64
 782         .vread          = vread_hpet,
 783 #endif
 784 };
 785
 786 static int hpet_clocksource_register(void)
 787 {
 788         u64 start, now;
 789         cycle_t t1;
 790
 791         /* Start the counter */
 792         hpet_restart_counter();
 793
 794         /* Verify whether hpet counter works */
 795         t1 = hpet_readl(HPET_COUNTER);
 796         rdtscll(start);
 797
 798         /*
 799          * We don't know the TSC frequency yet, but waiting for
 800          * 200000 TSC cycles is safe:
 801          * 4 GHz == 50us
 802          * 1 GHz == 200us
 803          */
 804         do {
 805                 rep_nop();
 806                 rdtscll(now);
 807         } while ((now - start) < 200000UL);
 808
 809         if (t1 == hpet_readl(HPET_COUNTER)) {
 810                 printk(KERN_WARNING
 811                        "HPET counter not counting. HPET disabled\n");
 812                 return -ENODEV;
 813         }
 814
 815         /*
 816          * The definition of mult is (include/linux/clocksource.h)
 817          * mult/2^shift = ns/cyc and hpet_period is in units of fsec/cyc
 818          * so we first need to convert hpet_period to ns/cyc units:
 819          *  mult/2^shift = ns/cyc = hpet_period/10^6
 820          *  mult = (hpet_period * 2^shift)/10^6
 821          *  mult = (hpet_period << shift)/FSEC_PER_NSEC
 822          */
 823         clocksource_hpet.mult = div_sc(hpet_period, FSEC_PER_NSEC, HPET_SHIFT);
 824
 825         clocksource_register(&clocksource_hpet);
 826
 827         return 0;
 828 }
 829
 830 /**
 831  * hpet_enable - Try to setup the HPET timer. Returns 1 on success.
 832  */
 833 int __init hpet_enable(void)
 834 {
 835         unsigned int id;
 836         int i;
 837
 838         if (!is_hpet_capable())
 839                 return 0;
 840
 841         hpet_set_mapping();
 842
 843         /*
 844          * Read the period and check for a sane value:
 845          */
 846         hpet_period = hpet_readl(HPET_PERIOD);
 847
 848         /*
 849          * AMD SB700 based systems with spread spectrum enabled use a
 850          * SMM based HPET emulation to provide proper frequency
 851          * setting. The SMM code is initialized with the first HPET
 852          * register access and takes some time to complete. During
 853          * this time the config register reads 0xffffffff. We check
 854          * for max. 1000 loops whether the config register reads a non
 855          * 0xffffffff value to make sure that HPET is up and running
 856          * before we go further. A counting loop is safe, as the HPET
 857          * access takes thousands of CPU cycles. On non SB700 based
 858          * machines this check is only done once and has no side
 859          * effects.
 860          */
 861         for (i = 0; hpet_readl(HPET_CFG) == 0xFFFFFFFF; i++) {
 862                 if (i == 1000) {
 863                         printk(KERN_WARNING
 864                                "HPET config register value = 0xFFFFFFFF. "
 865                                "Disabling HPET\n");
 866                         goto out_nohpet;
 867                 }
 868         }
 869
 870         if (hpet_period < HPET_MIN_PERIOD || hpet_period > HPET_MAX_PERIOD)
 871                 goto out_nohpet;
 872
 873         /*
 874          * Read the HPET ID register to retrieve the IRQ routing
 875          * information and the number of channels
 876          */
 877         id = hpet_readl(HPET_ID);
 878         hpet_print_config();
 879
 880 #ifdef CONFIG_HPET_EMULATE_RTC
 881         /*
 882          * The legacy routing mode needs at least two channels, tick timer
 883          * and the rtc emulation channel.
 884          */
 885         if (!(id & HPET_ID_NUMBER))
 886                 goto out_nohpet;
 887 #endif
 888
 889         if (hpet_clocksource_register())
 890                 goto out_nohpet;
 891
 892         if (id & HPET_ID_LEGSUP) {
 893                 hpet_legacy_clockevent_register();
 894                 return 1;
 895         }
 896         return 0;
 897
 898 out_nohpet:
 899         hpet_clear_mapping();
 900         hpet_address = 0;
 901         return 0;
 902 }
 903
 904 /*
 905  * Needs to be late, as the reserve_timer code calls kalloc !
 906  *
 907  * Not a problem on i386 as hpet_enable is called from late_time_init,
 908  * but on x86_64 it is necessary !
 909  */
 910 static __init int hpet_late_init(void)
 911 {
 912         int cpu;
 913
 914         if (boot_hpet_disable)
 915                 return -ENODEV;
 916
 917         if (!hpet_address) {
 918                 if (!force_hpet_address)
 919                         return -ENODEV;
 920
 921                 hpet_address = force_hpet_address;
 922                 hpet_enable();
 923         }
 924
 925         if (!hpet_virt_address)
 926                 return -ENODEV;
 927
 928         if (hpet_readl(HPET_ID) & HPET_ID_LEGSUP)
 929                 hpet_msi_capability_lookup(2);
 930         else
 931                 hpet_msi_capability_lookup(0);
 932
 933         hpet_reserve_platform_timers(hpet_readl(HPET_ID));
 934         hpet_print_config();
 935
 936         if (hpet_msi_disable)
 937                 return 0;
 938
 939         if (boot_cpu_has(X86_FEATURE_ARAT))
 940                 return 0;
 941
 942         for_each_online_cpu(cpu) {
 943                 hpet_cpuhp_notify(NULL, CPU_ONLINE, (void *)(long)cpu);
 944         }
 945
 946         /* This notifier should be called after workqueue is ready */
 947         hotcpu_notifier(hpet_cpuhp_notify, -20);
 948
 949         return 0;
 950 }
 951 fs_initcall(hpet_late_init);
 952
 953 void hpet_disable(void)
 954 {
 955         if (is_hpet_capable()) {
 956                 unsigned int cfg = hpet_readl(HPET_CFG);
 957
 958                 if (hpet_legacy_int_enabled) {
 959                         cfg &= ~HPET_CFG_LEGACY;
 960                         hpet_legacy_int_enabled = 0;
 961                 }
 962                 cfg &= ~HPET_CFG_ENABLE;
 963                 hpet_writel(cfg, HPET_CFG);
 964         }
 965 }
 966
 967 #ifdef CONFIG_HPET_EMULATE_RTC
 968
 969 /* HPET in LegacyReplacement Mode eats up RTC interrupt line. When, HPET
 970  * is enabled, we support RTC interrupt functionality in software.
 971  * RTC has 3 kinds of interrupts:
 972  * 1) Update Interrupt - generate an interrupt, every sec, when RTC clock
 973  *    is updated
 974  * 2) Alarm Interrupt - generate an interrupt at a specific time of day
 975  * 3) Periodic Interrupt - generate periodic interrupt, with frequencies
 976  *    2Hz-8192Hz (2Hz-64Hz for non-root user) (all freqs in powers of 2)
 977  * (1) and (2) above are implemented using polling at a frequency of
 978  * 64 Hz. The exact frequency is a tradeoff between accuracy and interrupt
 979  * overhead. (DEFAULT_RTC_INT_FREQ)
 980  * For (3), we use interrupts at 64Hz or user specified periodic
 981  * frequency, whichever is higher.
 982  */
 983 #include <linux/mc146818rtc.h>
 984 #include <linux/rtc.h>
 985 #include <asm/rtc.h>
 986
 987 #define DEFAULT_RTC_INT_FREQ    64
 988 #define DEFAULT_RTC_SHIFT       6
 989 #define RTC_NUM_INTS            1
 990
 991 static unsigned long hpet_rtc_flags;
 992 static int hpet_prev_update_sec;
 993 static struct rtc_time hpet_alarm_time;
 994 static unsigned long hpet_pie_count;
 995 static u32 hpet_t1_cmp;
 996 static u32 hpet_default_delta;
 997 static u32 hpet_pie_delta;
 998 static unsigned long hpet_pie_limit;
 999
1000 static rtc_irq_handler irq_handler;
1001
1002 /*
1003  * Check that the hpet counter c1 is ahead of the c2
1004  */
1005 static inline int hpet_cnt_ahead(u32 c1, u32 c2)
1006 {
1007         return (s32)(c2 - c1) < 0;
1008 }
1009
1010 /*
1011  * Registers a IRQ handler.
1012  */
1013 int hpet_register_irq_handler(rtc_irq_handler handler)
1014 {
1015         if (!is_hpet_enabled())
1016                 return -ENODEV;
1017         if (irq_handler)
1018                 return -EBUSY;
1019
1020         irq_handler = handler;
1021
1022         return 0;
1023 }
1024 EXPORT_SYMBOL_GPL(hpet_register_irq_handler);
1025
1026 /*
1027  * Deregisters the IRQ handler registered with hpet_register_irq_handler()
1028  * and does cleanup.
1029  */
1030 void hpet_unregister_irq_handler(rtc_irq_handler handler)
1031 {
1032         if (!is_hpet_enabled())
1033                 return;
1034
1035         irq_handler = NULL;
1036         hpet_rtc_flags = 0;
1037 }
1038 EXPORT_SYMBOL_GPL(hpet_unregister_irq_handler);
1039
1040 /*
1041  * Timer 1 for RTC emulation. We use one shot mode, as periodic mode
1042  * is not supported by all HPET implementations for timer 1.
1043  *
1044  * hpet_rtc_timer_init() is called when the rtc is initialized.
1045  */
1046 int hpet_rtc_timer_init(void)
1047 {
1048         unsigned int cfg, cnt, delta;
1049         unsigned long flags;
1050
1051         if (!is_hpet_enabled())
1052                 return 0;
1053
1054         if (!hpet_default_delta) {
1055                 uint64_t clc;
1056
1057                 clc = (uint64_t) hpet_clockevent.mult * NSEC_PER_SEC;
1058                 clc >>= hpet_clockevent.shift + DEFAULT_RTC_SHIFT;
1059                 hpet_default_delta = clc;
1060         }
1061
1062         if (!(hpet_rtc_flags & RTC_PIE) || hpet_pie_limit)
1063                 delta = hpet_default_delta;
1064         else
1065                 delta = hpet_pie_delta;
1066
1067         local_irq_save(flags);
1068
1069         cnt = delta + hpet_readl(HPET_COUNTER);
1070         hpet_writel(cnt, HPET_T1_CMP);
1071         hpet_t1_cmp = cnt;
1072
1073         cfg = hpet_readl(HPET_T1_CFG);
1074         cfg &= ~HPET_TN_PERIODIC;
1075         cfg |= HPET_TN_ENABLE | HPET_TN_32BIT;
1076         hpet_writel(cfg, HPET_T1_CFG);
1077
1078         local_irq_restore(flags);
1079
1080         return 1;
1081 }
1082 EXPORT_SYMBOL_GPL(hpet_rtc_timer_init);
1083
1084 /*
1085  * The functions below are called from rtc driver.
1086  * Return 0 if HPET is not being used.
1087  * Otherwise do the necessary changes and return 1.
1088  */
1089 int hpet_mask_rtc_irq_bit(unsigned long bit_mask)
1090 {
1091         if (!is_hpet_enabled())
1092                 return 0;
1093
1094         hpet_rtc_flags &= ~bit_mask;
1095         return 1;
1096 }
1097 EXPORT_SYMBOL_GPL(hpet_mask_rtc_irq_bit);
1098
1099 int hpet_set_rtc_irq_bit(unsigned long bit_mask)
1100 {
1101         unsigned long oldbits = hpet_rtc_flags;
1102
1103         if (!is_hpet_enabled())
1104                 return 0;
1105
1106         hpet_rtc_flags |= bit_mask;
1107
1108         if ((bit_mask & RTC_UIE) && !(oldbits & RTC_UIE))
1109                 hpet_prev_update_sec = -1;
1110
1111         if (!oldbits)
1112                 hpet_rtc_timer_init();
1113
1114         return 1;
1115 }
1116 EXPORT_SYMBOL_GPL(hpet_set_rtc_irq_bit);
1117
1118 int hpet_set_alarm_time(unsigned char hrs, unsigned char min,
1119                         unsigned char sec)
1120 {
1121         if (!is_hpet_enabled())
1122                 return 0;
1123
1124         hpet_alarm_time.tm_hour = hrs;
1125         hpet_alarm_time.tm_min = min;
1126         hpet_alarm_time.tm_sec = sec;
1127
1128         return 1;
1129 }
1130 EXPORT_SYMBOL_GPL(hpet_set_alarm_time);
1131
1132 int hpet_set_periodic_freq(unsigned long freq)
1133 {
1134         uint64_t clc;
1135
1136         if (!is_hpet_enabled())
1137                 return 0;
1138
1139         if (freq <= DEFAULT_RTC_INT_FREQ)
1140                 hpet_pie_limit = DEFAULT_RTC_INT_FREQ / freq;
1141         else {
1142                 clc = (uint64_t) hpet_clockevent.mult * NSEC_PER_SEC;
1143                 do_div(clc, freq);
1144                 clc >>= hpet_clockevent.shift;
1145                 hpet_pie_delta = clc;
1146         }
1147         return 1;
1148 }
1149 EXPORT_SYMBOL_GPL(hpet_set_periodic_freq);
1150
1151 int hpet_rtc_dropped_irq(void)
1152 {
1153         return is_hpet_enabled();
1154 }
1155 EXPORT_SYMBOL_GPL(hpet_rtc_dropped_irq);
1156
1157 static void hpet_rtc_timer_reinit(void)
1158 {
1159         unsigned int cfg, delta;
1160         int lost_ints = -1;
1161
1162         if (unlikely(!hpet_rtc_flags)) {
1163                 cfg = hpet_readl(HPET_T1_CFG);
1164                 cfg &= ~HPET_TN_ENABLE;
1165                 hpet_writel(cfg, HPET_T1_CFG);
1166                 return;
1167         }
1168
1169         if (!(hpet_rtc_flags & RTC_PIE) || hpet_pie_limit)
1170                 delta = hpet_default_delta;
1171         else
1172                 delta = hpet_pie_delta;
1173
1174         /*
1175          * Increment the comparator value until we are ahead of the
1176          * current count.
1177          */
1178         do {
1179                 hpet_t1_cmp += delta;
1180                 hpet_writel(hpet_t1_cmp, HPET_T1_CMP);
1181                 lost_ints++;
1182         } while (!hpet_cnt_ahead(hpet_t1_cmp, hpet_readl(HPET_COUNTER)));
1183
1184         if (lost_ints) {
1185                 if (hpet_rtc_flags & RTC_PIE)
1186                         hpet_pie_count += lost_ints;
1187                 if (printk_ratelimit())
1188                         printk(KERN_WARNING "hpet1: lost %d rtc interrupts\n",
1189                                 lost_ints);
1190         }
1191 }
1192
1193 irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id)
1194 {
1195         struct rtc_time curr_time;
1196         unsigned long rtc_int_flag = 0;
1197
1198         hpet_rtc_timer_reinit();
1199         memset(&curr_time, 0, sizeof(struct rtc_time));
1200
1201         if (hpet_rtc_flags & (RTC_UIE | RTC_AIE))
1202                 get_rtc_time(&curr_time);
1203
1204         if (hpet_rtc_flags & RTC_UIE &&
1205             curr_time.tm_sec != hpet_prev_update_sec) {
1206                 if (hpet_prev_update_sec >= 0)
1207                         rtc_int_flag = RTC_UF;
1208                 hpet_prev_update_sec = curr_time.tm_sec;
1209         }
1210
1211         if (hpet_rtc_flags & RTC_PIE &&
1212             ++hpet_pie_count >= hpet_pie_limit) {
1213                 rtc_int_flag |= RTC_PF;
1214                 hpet_pie_count = 0;
1215         }
1216
1217         if (hpet_rtc_flags & RTC_AIE &&
1218             (curr_time.tm_sec == hpet_alarm_time.tm_sec) &&
1219             (curr_time.tm_min == hpet_alarm_time.tm_min) &&
1220             (curr_time.tm_hour == hpet_alarm_time.tm_hour))
1221                         rtc_int_flag |= RTC_AF;
1222
1223         if (rtc_int_flag) {
1224                 rtc_int_flag |= (RTC_IRQF | (RTC_NUM_INTS << 8));
1225                 if (irq_handler)
1226                         irq_handler(rtc_int_flag, dev_id);
1227         }
1228         return IRQ_HANDLED;
1229 }
1230 EXPORT_SYMBOL_GPL(hpet_rtc_interrupt);
1231 #endif