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