1 // SPDX-License-Identifier: GPL-2.0-only 2 #include <linux/clockchips.h> 3 #include <linux/interrupt.h> 4 #include <linux/export.h> 5 #include <linux/delay.h> 6 #include <linux/hpet.h> 7 #include <linux/cpu.h> 8 #include <linux/irq.h> 9 10 #include <asm/irq_remapping.h> 11 #include <asm/hpet.h> 12 #include <asm/time.h> 13 #include <asm/mwait.h> 14 15 #undef pr_fmt 16 #define pr_fmt(fmt) "hpet: " fmt 17 18 enum hpet_mode { 19 HPET_MODE_UNUSED, 20 HPET_MODE_LEGACY, 21 HPET_MODE_CLOCKEVT, 22 HPET_MODE_DEVICE, 23 }; 24 25 struct hpet_channel { 26 struct clock_event_device evt; 27 unsigned int num; 28 unsigned int cpu; 29 unsigned int irq; 30 unsigned int in_use; 31 enum hpet_mode mode; 32 unsigned int boot_cfg; 33 char name[10]; 34 }; 35 36 struct hpet_base { 37 unsigned int nr_channels; 38 unsigned int nr_clockevents; 39 unsigned int boot_cfg; 40 struct hpet_channel *channels; 41 }; 42 43 #define HPET_MASK CLOCKSOURCE_MASK(32) 44 45 #define HPET_MIN_CYCLES 128 46 #define HPET_MIN_PROG_DELTA (HPET_MIN_CYCLES + (HPET_MIN_CYCLES >> 1)) 47 48 /* 49 * HPET address is set in acpi/boot.c, when an ACPI entry exists 50 */ 51 unsigned long hpet_address; 52 u8 hpet_blockid; /* OS timer block num */ 53 bool hpet_msi_disable; 54 55 #ifdef CONFIG_GENERIC_MSI_IRQ 56 static DEFINE_PER_CPU(struct hpet_channel *, cpu_hpet_channel); 57 static struct irq_domain *hpet_domain; 58 #endif 59 60 static void __iomem *hpet_virt_address; 61 62 static struct hpet_base hpet_base; 63 64 static bool hpet_legacy_int_enabled; 65 static unsigned long hpet_freq; 66 67 bool boot_hpet_disable; 68 bool hpet_force_user; 69 static bool hpet_verbose; 70 71 static inline 72 struct hpet_channel *clockevent_to_channel(struct clock_event_device *evt) 73 { 74 return container_of(evt, struct hpet_channel, evt); 75 } 76 77 inline unsigned int hpet_readl(unsigned int a) 78 { 79 return readl(hpet_virt_address + a); 80 } 81 82 static inline void hpet_writel(unsigned int d, unsigned int a) 83 { 84 writel(d, hpet_virt_address + a); 85 } 86 87 static inline void hpet_set_mapping(void) 88 { 89 hpet_virt_address = ioremap(hpet_address, HPET_MMAP_SIZE); 90 } 91 92 static inline void hpet_clear_mapping(void) 93 { 94 iounmap(hpet_virt_address); 95 hpet_virt_address = NULL; 96 } 97 98 /* 99 * HPET command line enable / disable 100 */ 101 static int __init hpet_setup(char *str) 102 { 103 while (str) { 104 char *next = strchr(str, ','); 105 106 if (next) 107 *next++ = 0; 108 if (!strncmp("disable", str, 7)) 109 boot_hpet_disable = true; 110 if (!strncmp("force", str, 5)) 111 hpet_force_user = true; 112 if (!strncmp("verbose", str, 7)) 113 hpet_verbose = true; 114 str = next; 115 } 116 return 1; 117 } 118 __setup("hpet=", hpet_setup); 119 120 static int __init disable_hpet(char *str) 121 { 122 boot_hpet_disable = true; 123 return 1; 124 } 125 __setup("nohpet", disable_hpet); 126 127 static inline int is_hpet_capable(void) 128 { 129 return !boot_hpet_disable && hpet_address; 130 } 131 132 /** 133 * is_hpet_enabled - Check whether the legacy HPET timer interrupt is enabled 134 */ 135 int is_hpet_enabled(void) 136 { 137 return is_hpet_capable() && hpet_legacy_int_enabled; 138 } 139 EXPORT_SYMBOL_GPL(is_hpet_enabled); 140 141 static void _hpet_print_config(const char *function, int line) 142 { 143 u32 i, id, period, cfg, status, channels, l, h; 144 145 pr_info("%s(%d):\n", function, line); 146 147 id = hpet_readl(HPET_ID); 148 period = hpet_readl(HPET_PERIOD); 149 pr_info("ID: 0x%x, PERIOD: 0x%x\n", id, period); 150 151 cfg = hpet_readl(HPET_CFG); 152 status = hpet_readl(HPET_STATUS); 153 pr_info("CFG: 0x%x, STATUS: 0x%x\n", cfg, status); 154 155 l = hpet_readl(HPET_COUNTER); 156 h = hpet_readl(HPET_COUNTER+4); 157 pr_info("COUNTER_l: 0x%x, COUNTER_h: 0x%x\n", l, h); 158 159 channels = ((id & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT) + 1; 160 161 for (i = 0; i < channels; i++) { 162 l = hpet_readl(HPET_Tn_CFG(i)); 163 h = hpet_readl(HPET_Tn_CFG(i)+4); 164 pr_info("T%d: CFG_l: 0x%x, CFG_h: 0x%x\n", i, l, h); 165 166 l = hpet_readl(HPET_Tn_CMP(i)); 167 h = hpet_readl(HPET_Tn_CMP(i)+4); 168 pr_info("T%d: CMP_l: 0x%x, CMP_h: 0x%x\n", i, l, h); 169 170 l = hpet_readl(HPET_Tn_ROUTE(i)); 171 h = hpet_readl(HPET_Tn_ROUTE(i)+4); 172 pr_info("T%d ROUTE_l: 0x%x, ROUTE_h: 0x%x\n", i, l, h); 173 } 174 } 175 176 #define hpet_print_config() \ 177 do { \ 178 if (hpet_verbose) \ 179 _hpet_print_config(__func__, __LINE__); \ 180 } while (0) 181 182 /* 183 * When the HPET driver (/dev/hpet) is enabled, we need to reserve 184 * timer 0 and timer 1 in case of RTC emulation. 185 */ 186 #ifdef CONFIG_HPET 187 188 static void __init hpet_reserve_platform_timers(void) 189 { 190 struct hpet_data hd; 191 unsigned int i; 192 193 memset(&hd, 0, sizeof(hd)); 194 hd.hd_phys_address = hpet_address; 195 hd.hd_address = hpet_virt_address; 196 hd.hd_nirqs = hpet_base.nr_channels; 197 198 /* 199 * NOTE that hd_irq[] reflects IOAPIC input pins (LEGACY_8254 200 * is wrong for i8259!) not the output IRQ. Many BIOS writers 201 * don't bother configuring *any* comparator interrupts. 202 */ 203 hd.hd_irq[0] = HPET_LEGACY_8254; 204 hd.hd_irq[1] = HPET_LEGACY_RTC; 205 206 for (i = 0; i < hpet_base.nr_channels; i++) { 207 struct hpet_channel *hc = hpet_base.channels + i; 208 209 if (i >= 2) 210 hd.hd_irq[i] = hc->irq; 211 212 switch (hc->mode) { 213 case HPET_MODE_UNUSED: 214 case HPET_MODE_DEVICE: 215 hc->mode = HPET_MODE_DEVICE; 216 break; 217 case HPET_MODE_CLOCKEVT: 218 case HPET_MODE_LEGACY: 219 hpet_reserve_timer(&hd, hc->num); 220 break; 221 } 222 } 223 224 hpet_alloc(&hd); 225 } 226 227 static void __init hpet_select_device_channel(void) 228 { 229 int i; 230 231 for (i = 0; i < hpet_base.nr_channels; i++) { 232 struct hpet_channel *hc = hpet_base.channels + i; 233 234 /* Associate the first unused channel to /dev/hpet */ 235 if (hc->mode == HPET_MODE_UNUSED) { 236 hc->mode = HPET_MODE_DEVICE; 237 return; 238 } 239 } 240 } 241 242 #else 243 static inline void hpet_reserve_platform_timers(void) { } 244 static inline void hpet_select_device_channel(void) {} 245 #endif 246 247 /* Common HPET functions */ 248 static void hpet_stop_counter(void) 249 { 250 u32 cfg = hpet_readl(HPET_CFG); 251 252 cfg &= ~HPET_CFG_ENABLE; 253 hpet_writel(cfg, HPET_CFG); 254 } 255 256 static void hpet_reset_counter(void) 257 { 258 hpet_writel(0, HPET_COUNTER); 259 hpet_writel(0, HPET_COUNTER + 4); 260 } 261 262 static void hpet_start_counter(void) 263 { 264 unsigned int cfg = hpet_readl(HPET_CFG); 265 266 cfg |= HPET_CFG_ENABLE; 267 hpet_writel(cfg, HPET_CFG); 268 } 269 270 static void hpet_restart_counter(void) 271 { 272 hpet_stop_counter(); 273 hpet_reset_counter(); 274 hpet_start_counter(); 275 } 276 277 static void hpet_resume_device(void) 278 { 279 force_hpet_resume(); 280 } 281 282 static void hpet_resume_counter(struct clocksource *cs) 283 { 284 hpet_resume_device(); 285 hpet_restart_counter(); 286 } 287 288 static void hpet_enable_legacy_int(void) 289 { 290 unsigned int cfg = hpet_readl(HPET_CFG); 291 292 cfg |= HPET_CFG_LEGACY; 293 hpet_writel(cfg, HPET_CFG); 294 hpet_legacy_int_enabled = true; 295 } 296 297 static int hpet_clkevt_set_state_periodic(struct clock_event_device *evt) 298 { 299 unsigned int channel = clockevent_to_channel(evt)->num; 300 unsigned int cfg, cmp, now; 301 uint64_t delta; 302 303 hpet_stop_counter(); 304 delta = ((uint64_t)(NSEC_PER_SEC / HZ)) * evt->mult; 305 delta >>= evt->shift; 306 now = hpet_readl(HPET_COUNTER); 307 cmp = now + (unsigned int)delta; 308 cfg = hpet_readl(HPET_Tn_CFG(channel)); 309 cfg |= HPET_TN_ENABLE | HPET_TN_PERIODIC | HPET_TN_SETVAL | 310 HPET_TN_32BIT; 311 hpet_writel(cfg, HPET_Tn_CFG(channel)); 312 hpet_writel(cmp, HPET_Tn_CMP(channel)); 313 udelay(1); 314 /* 315 * HPET on AMD 81xx needs a second write (with HPET_TN_SETVAL 316 * cleared) to T0_CMP to set the period. The HPET_TN_SETVAL 317 * bit is automatically cleared after the first write. 318 * (See AMD-8111 HyperTransport I/O Hub Data Sheet, 319 * Publication # 24674) 320 */ 321 hpet_writel((unsigned int)delta, HPET_Tn_CMP(channel)); 322 hpet_start_counter(); 323 hpet_print_config(); 324 325 return 0; 326 } 327 328 static int hpet_clkevt_set_state_oneshot(struct clock_event_device *evt) 329 { 330 unsigned int channel = clockevent_to_channel(evt)->num; 331 unsigned int cfg; 332 333 cfg = hpet_readl(HPET_Tn_CFG(channel)); 334 cfg &= ~HPET_TN_PERIODIC; 335 cfg |= HPET_TN_ENABLE | HPET_TN_32BIT; 336 hpet_writel(cfg, HPET_Tn_CFG(channel)); 337 338 return 0; 339 } 340 341 static int hpet_clkevt_set_state_shutdown(struct clock_event_device *evt) 342 { 343 unsigned int channel = clockevent_to_channel(evt)->num; 344 unsigned int cfg; 345 346 cfg = hpet_readl(HPET_Tn_CFG(channel)); 347 cfg &= ~HPET_TN_ENABLE; 348 hpet_writel(cfg, HPET_Tn_CFG(channel)); 349 350 return 0; 351 } 352 353 static int hpet_clkevt_legacy_resume(struct clock_event_device *evt) 354 { 355 hpet_enable_legacy_int(); 356 hpet_print_config(); 357 return 0; 358 } 359 360 static int 361 hpet_clkevt_set_next_event(unsigned long delta, struct clock_event_device *evt) 362 { 363 unsigned int channel = clockevent_to_channel(evt)->num; 364 u32 cnt; 365 s32 res; 366 367 cnt = hpet_readl(HPET_COUNTER); 368 cnt += (u32) delta; 369 hpet_writel(cnt, HPET_Tn_CMP(channel)); 370 371 /* 372 * HPETs are a complete disaster. The compare register is 373 * based on a equal comparison and neither provides a less 374 * than or equal functionality (which would require to take 375 * the wraparound into account) nor a simple count down event 376 * mode. Further the write to the comparator register is 377 * delayed internally up to two HPET clock cycles in certain 378 * chipsets (ATI, ICH9,10). Some newer AMD chipsets have even 379 * longer delays. We worked around that by reading back the 380 * compare register, but that required another workaround for 381 * ICH9,10 chips where the first readout after write can 382 * return the old stale value. We already had a minimum 383 * programming delta of 5us enforced, but a NMI or SMI hitting 384 * between the counter readout and the comparator write can 385 * move us behind that point easily. Now instead of reading 386 * the compare register back several times, we make the ETIME 387 * decision based on the following: Return ETIME if the 388 * counter value after the write is less than HPET_MIN_CYCLES 389 * away from the event or if the counter is already ahead of 390 * the event. The minimum programming delta for the generic 391 * clockevents code is set to 1.5 * HPET_MIN_CYCLES. 392 */ 393 res = (s32)(cnt - hpet_readl(HPET_COUNTER)); 394 395 return res < HPET_MIN_CYCLES ? -ETIME : 0; 396 } 397 398 static void hpet_init_clockevent(struct hpet_channel *hc, unsigned int rating) 399 { 400 struct clock_event_device *evt = &hc->evt; 401 402 evt->rating = rating; 403 evt->irq = hc->irq; 404 evt->name = hc->name; 405 evt->cpumask = cpumask_of(hc->cpu); 406 evt->set_state_oneshot = hpet_clkevt_set_state_oneshot; 407 evt->set_next_event = hpet_clkevt_set_next_event; 408 evt->set_state_shutdown = hpet_clkevt_set_state_shutdown; 409 410 evt->features = CLOCK_EVT_FEAT_ONESHOT; 411 if (hc->boot_cfg & HPET_TN_PERIODIC) { 412 evt->features |= CLOCK_EVT_FEAT_PERIODIC; 413 evt->set_state_periodic = hpet_clkevt_set_state_periodic; 414 } 415 } 416 417 static void __init hpet_legacy_clockevent_register(struct hpet_channel *hc) 418 { 419 /* 420 * Start HPET with the boot CPU's cpumask and make it global after 421 * the IO_APIC has been initialized. 422 */ 423 hc->cpu = boot_cpu_data.cpu_index; 424 strncpy(hc->name, "hpet", sizeof(hc->name)); 425 hpet_init_clockevent(hc, 50); 426 427 hc->evt.tick_resume = hpet_clkevt_legacy_resume; 428 429 /* 430 * Legacy horrors and sins from the past. HPET used periodic mode 431 * unconditionally forever on the legacy channel 0. Removing the 432 * below hack and using the conditional in hpet_init_clockevent() 433 * makes at least Qemu and one hardware machine fail to boot. 434 * There are two issues which cause the boot failure: 435 * 436 * #1 After the timer delivery test in IOAPIC and the IOAPIC setup 437 * the next interrupt is not delivered despite the HPET channel 438 * being programmed correctly. Reprogramming the HPET after 439 * switching to IOAPIC makes it work again. After fixing this, 440 * the next issue surfaces: 441 * 442 * #2 Due to the unconditional periodic mode availability the Local 443 * APIC timer calibration can hijack the global clockevents 444 * event handler without causing damage. Using oneshot at this 445 * stage makes if hang because the HPET does not get 446 * reprogrammed due to the handler hijacking. Duh, stupid me! 447 * 448 * Both issues require major surgery and especially the kick HPET 449 * again after enabling IOAPIC results in really nasty hackery. 450 * This 'assume periodic works' magic has survived since HPET 451 * support got added, so it's questionable whether this should be 452 * fixed. Both Qemu and the failing hardware machine support 453 * periodic mode despite the fact that both don't advertise it in 454 * the configuration register and both need that extra kick after 455 * switching to IOAPIC. Seems to be a feature... 456 */ 457 hc->evt.features |= CLOCK_EVT_FEAT_PERIODIC; 458 hc->evt.set_state_periodic = hpet_clkevt_set_state_periodic; 459 460 /* Start HPET legacy interrupts */ 461 hpet_enable_legacy_int(); 462 463 clockevents_config_and_register(&hc->evt, hpet_freq, 464 HPET_MIN_PROG_DELTA, 0x7FFFFFFF); 465 global_clock_event = &hc->evt; 466 pr_debug("Clockevent registered\n"); 467 } 468 469 /* 470 * HPET MSI Support 471 */ 472 #ifdef CONFIG_GENERIC_MSI_IRQ 473 static void hpet_msi_unmask(struct irq_data *data) 474 { 475 struct hpet_channel *hc = irq_data_get_irq_handler_data(data); 476 unsigned int cfg; 477 478 cfg = hpet_readl(HPET_Tn_CFG(hc->num)); 479 cfg |= HPET_TN_ENABLE | HPET_TN_FSB; 480 hpet_writel(cfg, HPET_Tn_CFG(hc->num)); 481 } 482 483 static void hpet_msi_mask(struct irq_data *data) 484 { 485 struct hpet_channel *hc = irq_data_get_irq_handler_data(data); 486 unsigned int cfg; 487 488 cfg = hpet_readl(HPET_Tn_CFG(hc->num)); 489 cfg &= ~(HPET_TN_ENABLE | HPET_TN_FSB); 490 hpet_writel(cfg, HPET_Tn_CFG(hc->num)); 491 } 492 493 static void hpet_msi_write(struct hpet_channel *hc, struct msi_msg *msg) 494 { 495 hpet_writel(msg->data, HPET_Tn_ROUTE(hc->num)); 496 hpet_writel(msg->address_lo, HPET_Tn_ROUTE(hc->num) + 4); 497 } 498 499 static void hpet_msi_write_msg(struct irq_data *data, struct msi_msg *msg) 500 { 501 hpet_msi_write(irq_data_get_irq_handler_data(data), msg); 502 } 503 504 static struct irq_chip hpet_msi_controller __ro_after_init = { 505 .name = "HPET-MSI", 506 .irq_unmask = hpet_msi_unmask, 507 .irq_mask = hpet_msi_mask, 508 .irq_ack = irq_chip_ack_parent, 509 .irq_set_affinity = msi_domain_set_affinity, 510 .irq_retrigger = irq_chip_retrigger_hierarchy, 511 .irq_write_msi_msg = hpet_msi_write_msg, 512 .flags = IRQCHIP_SKIP_SET_WAKE | IRQCHIP_AFFINITY_PRE_STARTUP, 513 }; 514 515 static int hpet_msi_init(struct irq_domain *domain, 516 struct msi_domain_info *info, unsigned int virq, 517 irq_hw_number_t hwirq, msi_alloc_info_t *arg) 518 { 519 irq_set_status_flags(virq, IRQ_MOVE_PCNTXT); 520 irq_domain_set_info(domain, virq, arg->hwirq, info->chip, NULL, 521 handle_edge_irq, arg->data, "edge"); 522 523 return 0; 524 } 525 526 static void hpet_msi_free(struct irq_domain *domain, 527 struct msi_domain_info *info, unsigned int virq) 528 { 529 irq_clear_status_flags(virq, IRQ_MOVE_PCNTXT); 530 } 531 532 static struct msi_domain_ops hpet_msi_domain_ops = { 533 .msi_init = hpet_msi_init, 534 .msi_free = hpet_msi_free, 535 }; 536 537 static struct msi_domain_info hpet_msi_domain_info = { 538 .ops = &hpet_msi_domain_ops, 539 .chip = &hpet_msi_controller, 540 .flags = MSI_FLAG_USE_DEF_DOM_OPS, 541 }; 542 543 static struct irq_domain *hpet_create_irq_domain(int hpet_id) 544 { 545 struct msi_domain_info *domain_info; 546 struct irq_domain *parent, *d; 547 struct fwnode_handle *fn; 548 struct irq_fwspec fwspec; 549 550 if (x86_vector_domain == NULL) 551 return NULL; 552 553 domain_info = kzalloc(sizeof(*domain_info), GFP_KERNEL); 554 if (!domain_info) 555 return NULL; 556 557 *domain_info = hpet_msi_domain_info; 558 domain_info->data = (void *)(long)hpet_id; 559 560 fn = irq_domain_alloc_named_id_fwnode(hpet_msi_controller.name, 561 hpet_id); 562 if (!fn) { 563 kfree(domain_info); 564 return NULL; 565 } 566 567 fwspec.fwnode = fn; 568 fwspec.param_count = 1; 569 fwspec.param[0] = hpet_id; 570 571 parent = irq_find_matching_fwspec(&fwspec, DOMAIN_BUS_ANY); 572 if (!parent) { 573 irq_domain_free_fwnode(fn); 574 kfree(domain_info); 575 return NULL; 576 } 577 if (parent != x86_vector_domain) 578 hpet_msi_controller.name = "IR-HPET-MSI"; 579 580 d = msi_create_irq_domain(fn, domain_info, parent); 581 if (!d) { 582 irq_domain_free_fwnode(fn); 583 kfree(domain_info); 584 } 585 return d; 586 } 587 588 static inline int hpet_dev_id(struct irq_domain *domain) 589 { 590 struct msi_domain_info *info = msi_get_domain_info(domain); 591 592 return (int)(long)info->data; 593 } 594 595 static int hpet_assign_irq(struct irq_domain *domain, struct hpet_channel *hc, 596 int dev_num) 597 { 598 struct irq_alloc_info info; 599 600 init_irq_alloc_info(&info, NULL); 601 info.type = X86_IRQ_ALLOC_TYPE_HPET; 602 info.data = hc; 603 info.devid = hpet_dev_id(domain); 604 info.hwirq = dev_num; 605 606 return irq_domain_alloc_irqs(domain, 1, NUMA_NO_NODE, &info); 607 } 608 609 static int hpet_clkevt_msi_resume(struct clock_event_device *evt) 610 { 611 struct hpet_channel *hc = clockevent_to_channel(evt); 612 struct irq_data *data = irq_get_irq_data(hc->irq); 613 struct msi_msg msg; 614 615 /* Restore the MSI msg and unmask the interrupt */ 616 irq_chip_compose_msi_msg(data, &msg); 617 hpet_msi_write(hc, &msg); 618 hpet_msi_unmask(data); 619 return 0; 620 } 621 622 static irqreturn_t hpet_msi_interrupt_handler(int irq, void *data) 623 { 624 struct hpet_channel *hc = data; 625 struct clock_event_device *evt = &hc->evt; 626 627 if (!evt->event_handler) { 628 pr_info("Spurious interrupt HPET channel %d\n", hc->num); 629 return IRQ_HANDLED; 630 } 631 632 evt->event_handler(evt); 633 return IRQ_HANDLED; 634 } 635 636 static int hpet_setup_msi_irq(struct hpet_channel *hc) 637 { 638 if (request_irq(hc->irq, hpet_msi_interrupt_handler, 639 IRQF_TIMER | IRQF_NOBALANCING, 640 hc->name, hc)) 641 return -1; 642 643 disable_irq(hc->irq); 644 irq_set_affinity(hc->irq, cpumask_of(hc->cpu)); 645 enable_irq(hc->irq); 646 647 pr_debug("%s irq %u for MSI\n", hc->name, hc->irq); 648 649 return 0; 650 } 651 652 /* Invoked from the hotplug callback on @cpu */ 653 static void init_one_hpet_msi_clockevent(struct hpet_channel *hc, int cpu) 654 { 655 struct clock_event_device *evt = &hc->evt; 656 657 hc->cpu = cpu; 658 per_cpu(cpu_hpet_channel, cpu) = hc; 659 hpet_setup_msi_irq(hc); 660 661 hpet_init_clockevent(hc, 110); 662 evt->tick_resume = hpet_clkevt_msi_resume; 663 664 clockevents_config_and_register(evt, hpet_freq, HPET_MIN_PROG_DELTA, 665 0x7FFFFFFF); 666 } 667 668 static struct hpet_channel *hpet_get_unused_clockevent(void) 669 { 670 int i; 671 672 for (i = 0; i < hpet_base.nr_channels; i++) { 673 struct hpet_channel *hc = hpet_base.channels + i; 674 675 if (hc->mode != HPET_MODE_CLOCKEVT || hc->in_use) 676 continue; 677 hc->in_use = 1; 678 return hc; 679 } 680 return NULL; 681 } 682 683 static int hpet_cpuhp_online(unsigned int cpu) 684 { 685 struct hpet_channel *hc = hpet_get_unused_clockevent(); 686 687 if (hc) 688 init_one_hpet_msi_clockevent(hc, cpu); 689 return 0; 690 } 691 692 static int hpet_cpuhp_dead(unsigned int cpu) 693 { 694 struct hpet_channel *hc = per_cpu(cpu_hpet_channel, cpu); 695 696 if (!hc) 697 return 0; 698 free_irq(hc->irq, hc); 699 hc->in_use = 0; 700 per_cpu(cpu_hpet_channel, cpu) = NULL; 701 return 0; 702 } 703 704 static void __init hpet_select_clockevents(void) 705 { 706 unsigned int i; 707 708 hpet_base.nr_clockevents = 0; 709 710 /* No point if MSI is disabled or CPU has an Always Runing APIC Timer */ 711 if (hpet_msi_disable || boot_cpu_has(X86_FEATURE_ARAT)) 712 return; 713 714 hpet_print_config(); 715 716 hpet_domain = hpet_create_irq_domain(hpet_blockid); 717 if (!hpet_domain) 718 return; 719 720 for (i = 0; i < hpet_base.nr_channels; i++) { 721 struct hpet_channel *hc = hpet_base.channels + i; 722 int irq; 723 724 if (hc->mode != HPET_MODE_UNUSED) 725 continue; 726 727 /* Only consider HPET channel with MSI support */ 728 if (!(hc->boot_cfg & HPET_TN_FSB_CAP)) 729 continue; 730 731 sprintf(hc->name, "hpet%d", i); 732 733 irq = hpet_assign_irq(hpet_domain, hc, hc->num); 734 if (irq <= 0) 735 continue; 736 737 hc->irq = irq; 738 hc->mode = HPET_MODE_CLOCKEVT; 739 740 if (++hpet_base.nr_clockevents == num_possible_cpus()) 741 break; 742 } 743 744 pr_info("%d channels of %d reserved for per-cpu timers\n", 745 hpet_base.nr_channels, hpet_base.nr_clockevents); 746 } 747 748 #else 749 750 static inline void hpet_select_clockevents(void) { } 751 752 #define hpet_cpuhp_online NULL 753 #define hpet_cpuhp_dead NULL 754 755 #endif 756 757 /* 758 * Clock source related code 759 */ 760 #if defined(CONFIG_SMP) && defined(CONFIG_64BIT) 761 /* 762 * Reading the HPET counter is a very slow operation. If a large number of 763 * CPUs are trying to access the HPET counter simultaneously, it can cause 764 * massive delays and slow down system performance dramatically. This may 765 * happen when HPET is the default clock source instead of TSC. For a 766 * really large system with hundreds of CPUs, the slowdown may be so 767 * severe, that it can actually crash the system because of a NMI watchdog 768 * soft lockup, for example. 769 * 770 * If multiple CPUs are trying to access the HPET counter at the same time, 771 * we don't actually need to read the counter multiple times. Instead, the 772 * other CPUs can use the counter value read by the first CPU in the group. 773 * 774 * This special feature is only enabled on x86-64 systems. It is unlikely 775 * that 32-bit x86 systems will have enough CPUs to require this feature 776 * with its associated locking overhead. We also need 64-bit atomic read. 777 * 778 * The lock and the HPET value are stored together and can be read in a 779 * single atomic 64-bit read. It is explicitly assumed that arch_spinlock_t 780 * is 32 bits in size. 781 */ 782 union hpet_lock { 783 struct { 784 arch_spinlock_t lock; 785 u32 value; 786 }; 787 u64 lockval; 788 }; 789 790 static union hpet_lock hpet __cacheline_aligned = { 791 { .lock = __ARCH_SPIN_LOCK_UNLOCKED, }, 792 }; 793 794 static u64 read_hpet(struct clocksource *cs) 795 { 796 unsigned long flags; 797 union hpet_lock old, new; 798 799 BUILD_BUG_ON(sizeof(union hpet_lock) != 8); 800 801 /* 802 * Read HPET directly if in NMI. 803 */ 804 if (in_nmi()) 805 return (u64)hpet_readl(HPET_COUNTER); 806 807 /* 808 * Read the current state of the lock and HPET value atomically. 809 */ 810 old.lockval = READ_ONCE(hpet.lockval); 811 812 if (arch_spin_is_locked(&old.lock)) 813 goto contended; 814 815 local_irq_save(flags); 816 if (arch_spin_trylock(&hpet.lock)) { 817 new.value = hpet_readl(HPET_COUNTER); 818 /* 819 * Use WRITE_ONCE() to prevent store tearing. 820 */ 821 WRITE_ONCE(hpet.value, new.value); 822 arch_spin_unlock(&hpet.lock); 823 local_irq_restore(flags); 824 return (u64)new.value; 825 } 826 local_irq_restore(flags); 827 828 contended: 829 /* 830 * Contended case 831 * -------------- 832 * Wait until the HPET value change or the lock is free to indicate 833 * its value is up-to-date. 834 * 835 * It is possible that old.value has already contained the latest 836 * HPET value while the lock holder was in the process of releasing 837 * the lock. Checking for lock state change will enable us to return 838 * the value immediately instead of waiting for the next HPET reader 839 * to come along. 840 */ 841 do { 842 cpu_relax(); 843 new.lockval = READ_ONCE(hpet.lockval); 844 } while ((new.value == old.value) && arch_spin_is_locked(&new.lock)); 845 846 return (u64)new.value; 847 } 848 #else 849 /* 850 * For UP or 32-bit. 851 */ 852 static u64 read_hpet(struct clocksource *cs) 853 { 854 return (u64)hpet_readl(HPET_COUNTER); 855 } 856 #endif 857 858 static struct clocksource clocksource_hpet = { 859 .name = "hpet", 860 .rating = 250, 861 .read = read_hpet, 862 .mask = HPET_MASK, 863 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 864 .resume = hpet_resume_counter, 865 }; 866 867 /* 868 * AMD SB700 based systems with spread spectrum enabled use a SMM based 869 * HPET emulation to provide proper frequency setting. 870 * 871 * On such systems the SMM code is initialized with the first HPET register 872 * access and takes some time to complete. During this time the config 873 * register reads 0xffffffff. We check for max 1000 loops whether the 874 * config register reads a non-0xffffffff value to make sure that the 875 * HPET is up and running before we proceed any further. 876 * 877 * A counting loop is safe, as the HPET access takes thousands of CPU cycles. 878 * 879 * On non-SB700 based machines this check is only done once and has no 880 * side effects. 881 */ 882 static bool __init hpet_cfg_working(void) 883 { 884 int i; 885 886 for (i = 0; i < 1000; i++) { 887 if (hpet_readl(HPET_CFG) != 0xFFFFFFFF) 888 return true; 889 } 890 891 pr_warn("Config register invalid. Disabling HPET\n"); 892 return false; 893 } 894 895 static bool __init hpet_counting(void) 896 { 897 u64 start, now, t1; 898 899 hpet_restart_counter(); 900 901 t1 = hpet_readl(HPET_COUNTER); 902 start = rdtsc(); 903 904 /* 905 * We don't know the TSC frequency yet, but waiting for 906 * 200000 TSC cycles is safe: 907 * 4 GHz == 50us 908 * 1 GHz == 200us 909 */ 910 do { 911 if (t1 != hpet_readl(HPET_COUNTER)) 912 return true; 913 now = rdtsc(); 914 } while ((now - start) < 200000UL); 915 916 pr_warn("Counter not counting. HPET disabled\n"); 917 return false; 918 } 919 920 static bool __init mwait_pc10_supported(void) 921 { 922 unsigned int eax, ebx, ecx, mwait_substates; 923 924 if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL) 925 return false; 926 927 if (!cpu_feature_enabled(X86_FEATURE_MWAIT)) 928 return false; 929 930 if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF) 931 return false; 932 933 cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &mwait_substates); 934 935 return (ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) && 936 (ecx & CPUID5_ECX_INTERRUPT_BREAK) && 937 (mwait_substates & (0xF << 28)); 938 } 939 940 /* 941 * Check whether the system supports PC10. If so force disable HPET as that 942 * stops counting in PC10. This check is overbroad as it does not take any 943 * of the following into account: 944 * 945 * - ACPI tables 946 * - Enablement of intel_idle 947 * - Command line arguments which limit intel_idle C-state support 948 * 949 * That's perfectly fine. HPET is a piece of hardware designed by committee 950 * and the only reasons why it is still in use on modern systems is the 951 * fact that it is impossible to reliably query TSC and CPU frequency via 952 * CPUID or firmware. 953 * 954 * If HPET is functional it is useful for calibrating TSC, but this can be 955 * done via PMTIMER as well which seems to be the last remaining timer on 956 * X86/INTEL platforms that has not been completely wreckaged by feature 957 * creep. 958 * 959 * In theory HPET support should be removed altogether, but there are older 960 * systems out there which depend on it because TSC and APIC timer are 961 * dysfunctional in deeper C-states. 962 * 963 * It's only 20 years now that hardware people have been asked to provide 964 * reliable and discoverable facilities which can be used for timekeeping 965 * and per CPU timer interrupts. 966 * 967 * The probability that this problem is going to be solved in the 968 * forseeable future is close to zero, so the kernel has to be cluttered 969 * with heuristics to keep up with the ever growing amount of hardware and 970 * firmware trainwrecks. Hopefully some day hardware people will understand 971 * that the approach of "This can be fixed in software" is not sustainable. 972 * Hope dies last... 973 */ 974 static bool __init hpet_is_pc10_damaged(void) 975 { 976 unsigned long long pcfg; 977 978 /* Check whether PC10 substates are supported */ 979 if (!mwait_pc10_supported()) 980 return false; 981 982 /* Check whether PC10 is enabled in PKG C-state limit */ 983 rdmsrl(MSR_PKG_CST_CONFIG_CONTROL, pcfg); 984 if ((pcfg & 0xF) < 8) 985 return false; 986 987 if (hpet_force_user) { 988 pr_warn("HPET force enabled via command line, but dysfunctional in PC10.\n"); 989 return false; 990 } 991 992 pr_info("HPET dysfunctional in PC10. Force disabled.\n"); 993 boot_hpet_disable = true; 994 return true; 995 } 996 997 /** 998 * hpet_enable - Try to setup the HPET timer. Returns 1 on success. 999 */ 1000 int __init hpet_enable(void) 1001 { 1002 u32 hpet_period, cfg, id, irq; 1003 unsigned int i, channels; 1004 struct hpet_channel *hc; 1005 u64 freq; 1006 1007 if (!is_hpet_capable()) 1008 return 0; 1009 1010 if (hpet_is_pc10_damaged()) 1011 return 0; 1012 1013 hpet_set_mapping(); 1014 if (!hpet_virt_address) 1015 return 0; 1016 1017 /* Validate that the config register is working */ 1018 if (!hpet_cfg_working()) 1019 goto out_nohpet; 1020 1021 /* 1022 * Read the period and check for a sane value: 1023 */ 1024 hpet_period = hpet_readl(HPET_PERIOD); 1025 if (hpet_period < HPET_MIN_PERIOD || hpet_period > HPET_MAX_PERIOD) 1026 goto out_nohpet; 1027 1028 /* The period is a femtoseconds value. Convert it to a frequency. */ 1029 freq = FSEC_PER_SEC; 1030 do_div(freq, hpet_period); 1031 hpet_freq = freq; 1032 1033 /* 1034 * Read the HPET ID register to retrieve the IRQ routing 1035 * information and the number of channels 1036 */ 1037 id = hpet_readl(HPET_ID); 1038 hpet_print_config(); 1039 1040 /* This is the HPET channel number which is zero based */ 1041 channels = ((id & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT) + 1; 1042 1043 /* 1044 * The legacy routing mode needs at least two channels, tick timer 1045 * and the rtc emulation channel. 1046 */ 1047 if (IS_ENABLED(CONFIG_HPET_EMULATE_RTC) && channels < 2) 1048 goto out_nohpet; 1049 1050 hc = kcalloc(channels, sizeof(*hc), GFP_KERNEL); 1051 if (!hc) { 1052 pr_warn("Disabling HPET.\n"); 1053 goto out_nohpet; 1054 } 1055 hpet_base.channels = hc; 1056 hpet_base.nr_channels = channels; 1057 1058 /* Read, store and sanitize the global configuration */ 1059 cfg = hpet_readl(HPET_CFG); 1060 hpet_base.boot_cfg = cfg; 1061 cfg &= ~(HPET_CFG_ENABLE | HPET_CFG_LEGACY); 1062 hpet_writel(cfg, HPET_CFG); 1063 if (cfg) 1064 pr_warn("Global config: Unknown bits %#x\n", cfg); 1065 1066 /* Read, store and sanitize the per channel configuration */ 1067 for (i = 0; i < channels; i++, hc++) { 1068 hc->num = i; 1069 1070 cfg = hpet_readl(HPET_Tn_CFG(i)); 1071 hc->boot_cfg = cfg; 1072 irq = (cfg & Tn_INT_ROUTE_CNF_MASK) >> Tn_INT_ROUTE_CNF_SHIFT; 1073 hc->irq = irq; 1074 1075 cfg &= ~(HPET_TN_ENABLE | HPET_TN_LEVEL | HPET_TN_FSB); 1076 hpet_writel(cfg, HPET_Tn_CFG(i)); 1077 1078 cfg &= ~(HPET_TN_PERIODIC | HPET_TN_PERIODIC_CAP 1079 | HPET_TN_64BIT_CAP | HPET_TN_32BIT | HPET_TN_ROUTE 1080 | HPET_TN_FSB | HPET_TN_FSB_CAP); 1081 if (cfg) 1082 pr_warn("Channel #%u config: Unknown bits %#x\n", i, cfg); 1083 } 1084 hpet_print_config(); 1085 1086 /* 1087 * Validate that the counter is counting. This needs to be done 1088 * after sanitizing the config registers to properly deal with 1089 * force enabled HPETs. 1090 */ 1091 if (!hpet_counting()) 1092 goto out_nohpet; 1093 1094 if (tsc_clocksource_watchdog_disabled()) 1095 clocksource_hpet.flags |= CLOCK_SOURCE_MUST_VERIFY; 1096 clocksource_register_hz(&clocksource_hpet, (u32)hpet_freq); 1097 1098 if (id & HPET_ID_LEGSUP) { 1099 hpet_legacy_clockevent_register(&hpet_base.channels[0]); 1100 hpet_base.channels[0].mode = HPET_MODE_LEGACY; 1101 if (IS_ENABLED(CONFIG_HPET_EMULATE_RTC)) 1102 hpet_base.channels[1].mode = HPET_MODE_LEGACY; 1103 return 1; 1104 } 1105 return 0; 1106 1107 out_nohpet: 1108 kfree(hpet_base.channels); 1109 hpet_base.channels = NULL; 1110 hpet_base.nr_channels = 0; 1111 hpet_clear_mapping(); 1112 hpet_address = 0; 1113 return 0; 1114 } 1115 1116 /* 1117 * The late initialization runs after the PCI quirks have been invoked 1118 * which might have detected a system on which the HPET can be enforced. 1119 * 1120 * Also, the MSI machinery is not working yet when the HPET is initialized 1121 * early. 1122 * 1123 * If the HPET is enabled, then: 1124 * 1125 * 1) Reserve one channel for /dev/hpet if CONFIG_HPET=y 1126 * 2) Reserve up to num_possible_cpus() channels as per CPU clockevents 1127 * 3) Setup /dev/hpet if CONFIG_HPET=y 1128 * 4) Register hotplug callbacks when clockevents are available 1129 */ 1130 static __init int hpet_late_init(void) 1131 { 1132 int ret; 1133 1134 if (!hpet_address) { 1135 if (!force_hpet_address) 1136 return -ENODEV; 1137 1138 hpet_address = force_hpet_address; 1139 hpet_enable(); 1140 } 1141 1142 if (!hpet_virt_address) 1143 return -ENODEV; 1144 1145 hpet_select_device_channel(); 1146 hpet_select_clockevents(); 1147 hpet_reserve_platform_timers(); 1148 hpet_print_config(); 1149 1150 if (!hpet_base.nr_clockevents) 1151 return 0; 1152 1153 ret = cpuhp_setup_state(CPUHP_AP_X86_HPET_ONLINE, "x86/hpet:online", 1154 hpet_cpuhp_online, NULL); 1155 if (ret) 1156 return ret; 1157 ret = cpuhp_setup_state(CPUHP_X86_HPET_DEAD, "x86/hpet:dead", NULL, 1158 hpet_cpuhp_dead); 1159 if (ret) 1160 goto err_cpuhp; 1161 return 0; 1162 1163 err_cpuhp: 1164 cpuhp_remove_state(CPUHP_AP_X86_HPET_ONLINE); 1165 return ret; 1166 } 1167 fs_initcall(hpet_late_init); 1168 1169 void hpet_disable(void) 1170 { 1171 unsigned int i; 1172 u32 cfg; 1173 1174 if (!is_hpet_capable() || !hpet_virt_address) 1175 return; 1176 1177 /* Restore boot configuration with the enable bit cleared */ 1178 cfg = hpet_base.boot_cfg; 1179 cfg &= ~HPET_CFG_ENABLE; 1180 hpet_writel(cfg, HPET_CFG); 1181 1182 /* Restore the channel boot configuration */ 1183 for (i = 0; i < hpet_base.nr_channels; i++) 1184 hpet_writel(hpet_base.channels[i].boot_cfg, HPET_Tn_CFG(i)); 1185 1186 /* If the HPET was enabled at boot time, reenable it */ 1187 if (hpet_base.boot_cfg & HPET_CFG_ENABLE) 1188 hpet_writel(hpet_base.boot_cfg, HPET_CFG); 1189 } 1190 1191 #ifdef CONFIG_HPET_EMULATE_RTC 1192 1193 /* 1194 * HPET in LegacyReplacement mode eats up the RTC interrupt line. When HPET 1195 * is enabled, we support RTC interrupt functionality in software. 1196 * 1197 * RTC has 3 kinds of interrupts: 1198 * 1199 * 1) Update Interrupt - generate an interrupt, every second, when the 1200 * RTC clock is updated 1201 * 2) Alarm Interrupt - generate an interrupt at a specific time of day 1202 * 3) Periodic Interrupt - generate periodic interrupt, with frequencies 1203 * 2Hz-8192Hz (2Hz-64Hz for non-root user) (all frequencies in powers of 2) 1204 * 1205 * (1) and (2) above are implemented using polling at a frequency of 64 Hz: 1206 * DEFAULT_RTC_INT_FREQ. 1207 * 1208 * The exact frequency is a tradeoff between accuracy and interrupt overhead. 1209 * 1210 * For (3), we use interrupts at 64 Hz, or the user specified periodic frequency, 1211 * if it's higher. 1212 */ 1213 #include <linux/mc146818rtc.h> 1214 #include <linux/rtc.h> 1215 1216 #define DEFAULT_RTC_INT_FREQ 64 1217 #define DEFAULT_RTC_SHIFT 6 1218 #define RTC_NUM_INTS 1 1219 1220 static unsigned long hpet_rtc_flags; 1221 static int hpet_prev_update_sec; 1222 static struct rtc_time hpet_alarm_time; 1223 static unsigned long hpet_pie_count; 1224 static u32 hpet_t1_cmp; 1225 static u32 hpet_default_delta; 1226 static u32 hpet_pie_delta; 1227 static unsigned long hpet_pie_limit; 1228 1229 static rtc_irq_handler irq_handler; 1230 1231 /* 1232 * Check that the HPET counter c1 is ahead of c2 1233 */ 1234 static inline int hpet_cnt_ahead(u32 c1, u32 c2) 1235 { 1236 return (s32)(c2 - c1) < 0; 1237 } 1238 1239 /* 1240 * Registers a IRQ handler. 1241 */ 1242 int hpet_register_irq_handler(rtc_irq_handler handler) 1243 { 1244 if (!is_hpet_enabled()) 1245 return -ENODEV; 1246 if (irq_handler) 1247 return -EBUSY; 1248 1249 irq_handler = handler; 1250 1251 return 0; 1252 } 1253 EXPORT_SYMBOL_GPL(hpet_register_irq_handler); 1254 1255 /* 1256 * Deregisters the IRQ handler registered with hpet_register_irq_handler() 1257 * and does cleanup. 1258 */ 1259 void hpet_unregister_irq_handler(rtc_irq_handler handler) 1260 { 1261 if (!is_hpet_enabled()) 1262 return; 1263 1264 irq_handler = NULL; 1265 hpet_rtc_flags = 0; 1266 } 1267 EXPORT_SYMBOL_GPL(hpet_unregister_irq_handler); 1268 1269 /* 1270 * Channel 1 for RTC emulation. We use one shot mode, as periodic mode 1271 * is not supported by all HPET implementations for channel 1. 1272 * 1273 * hpet_rtc_timer_init() is called when the rtc is initialized. 1274 */ 1275 int hpet_rtc_timer_init(void) 1276 { 1277 unsigned int cfg, cnt, delta; 1278 unsigned long flags; 1279 1280 if (!is_hpet_enabled()) 1281 return 0; 1282 1283 if (!hpet_default_delta) { 1284 struct clock_event_device *evt = &hpet_base.channels[0].evt; 1285 uint64_t clc; 1286 1287 clc = (uint64_t) evt->mult * NSEC_PER_SEC; 1288 clc >>= evt->shift + DEFAULT_RTC_SHIFT; 1289 hpet_default_delta = clc; 1290 } 1291 1292 if (!(hpet_rtc_flags & RTC_PIE) || hpet_pie_limit) 1293 delta = hpet_default_delta; 1294 else 1295 delta = hpet_pie_delta; 1296 1297 local_irq_save(flags); 1298 1299 cnt = delta + hpet_readl(HPET_COUNTER); 1300 hpet_writel(cnt, HPET_T1_CMP); 1301 hpet_t1_cmp = cnt; 1302 1303 cfg = hpet_readl(HPET_T1_CFG); 1304 cfg &= ~HPET_TN_PERIODIC; 1305 cfg |= HPET_TN_ENABLE | HPET_TN_32BIT; 1306 hpet_writel(cfg, HPET_T1_CFG); 1307 1308 local_irq_restore(flags); 1309 1310 return 1; 1311 } 1312 EXPORT_SYMBOL_GPL(hpet_rtc_timer_init); 1313 1314 static void hpet_disable_rtc_channel(void) 1315 { 1316 u32 cfg = hpet_readl(HPET_T1_CFG); 1317 1318 cfg &= ~HPET_TN_ENABLE; 1319 hpet_writel(cfg, HPET_T1_CFG); 1320 } 1321 1322 /* 1323 * The functions below are called from rtc driver. 1324 * Return 0 if HPET is not being used. 1325 * Otherwise do the necessary changes and return 1. 1326 */ 1327 int hpet_mask_rtc_irq_bit(unsigned long bit_mask) 1328 { 1329 if (!is_hpet_enabled()) 1330 return 0; 1331 1332 hpet_rtc_flags &= ~bit_mask; 1333 if (unlikely(!hpet_rtc_flags)) 1334 hpet_disable_rtc_channel(); 1335 1336 return 1; 1337 } 1338 EXPORT_SYMBOL_GPL(hpet_mask_rtc_irq_bit); 1339 1340 int hpet_set_rtc_irq_bit(unsigned long bit_mask) 1341 { 1342 unsigned long oldbits = hpet_rtc_flags; 1343 1344 if (!is_hpet_enabled()) 1345 return 0; 1346 1347 hpet_rtc_flags |= bit_mask; 1348 1349 if ((bit_mask & RTC_UIE) && !(oldbits & RTC_UIE)) 1350 hpet_prev_update_sec = -1; 1351 1352 if (!oldbits) 1353 hpet_rtc_timer_init(); 1354 1355 return 1; 1356 } 1357 EXPORT_SYMBOL_GPL(hpet_set_rtc_irq_bit); 1358 1359 int hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec) 1360 { 1361 if (!is_hpet_enabled()) 1362 return 0; 1363 1364 hpet_alarm_time.tm_hour = hrs; 1365 hpet_alarm_time.tm_min = min; 1366 hpet_alarm_time.tm_sec = sec; 1367 1368 return 1; 1369 } 1370 EXPORT_SYMBOL_GPL(hpet_set_alarm_time); 1371 1372 int hpet_set_periodic_freq(unsigned long freq) 1373 { 1374 uint64_t clc; 1375 1376 if (!is_hpet_enabled()) 1377 return 0; 1378 1379 if (freq <= DEFAULT_RTC_INT_FREQ) { 1380 hpet_pie_limit = DEFAULT_RTC_INT_FREQ / freq; 1381 } else { 1382 struct clock_event_device *evt = &hpet_base.channels[0].evt; 1383 1384 clc = (uint64_t) evt->mult * NSEC_PER_SEC; 1385 do_div(clc, freq); 1386 clc >>= evt->shift; 1387 hpet_pie_delta = clc; 1388 hpet_pie_limit = 0; 1389 } 1390 1391 return 1; 1392 } 1393 EXPORT_SYMBOL_GPL(hpet_set_periodic_freq); 1394 1395 int hpet_rtc_dropped_irq(void) 1396 { 1397 return is_hpet_enabled(); 1398 } 1399 EXPORT_SYMBOL_GPL(hpet_rtc_dropped_irq); 1400 1401 static void hpet_rtc_timer_reinit(void) 1402 { 1403 unsigned int delta; 1404 int lost_ints = -1; 1405 1406 if (unlikely(!hpet_rtc_flags)) 1407 hpet_disable_rtc_channel(); 1408 1409 if (!(hpet_rtc_flags & RTC_PIE) || hpet_pie_limit) 1410 delta = hpet_default_delta; 1411 else 1412 delta = hpet_pie_delta; 1413 1414 /* 1415 * Increment the comparator value until we are ahead of the 1416 * current count. 1417 */ 1418 do { 1419 hpet_t1_cmp += delta; 1420 hpet_writel(hpet_t1_cmp, HPET_T1_CMP); 1421 lost_ints++; 1422 } while (!hpet_cnt_ahead(hpet_t1_cmp, hpet_readl(HPET_COUNTER))); 1423 1424 if (lost_ints) { 1425 if (hpet_rtc_flags & RTC_PIE) 1426 hpet_pie_count += lost_ints; 1427 if (printk_ratelimit()) 1428 pr_warn("Lost %d RTC interrupts\n", lost_ints); 1429 } 1430 } 1431 1432 irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id) 1433 { 1434 struct rtc_time curr_time; 1435 unsigned long rtc_int_flag = 0; 1436 1437 hpet_rtc_timer_reinit(); 1438 memset(&curr_time, 0, sizeof(struct rtc_time)); 1439 1440 if (hpet_rtc_flags & (RTC_UIE | RTC_AIE)) { 1441 if (unlikely(mc146818_get_time(&curr_time) < 0)) { 1442 pr_err_ratelimited("unable to read current time from RTC\n"); 1443 return IRQ_HANDLED; 1444 } 1445 } 1446 1447 if (hpet_rtc_flags & RTC_UIE && 1448 curr_time.tm_sec != hpet_prev_update_sec) { 1449 if (hpet_prev_update_sec >= 0) 1450 rtc_int_flag = RTC_UF; 1451 hpet_prev_update_sec = curr_time.tm_sec; 1452 } 1453 1454 if (hpet_rtc_flags & RTC_PIE && ++hpet_pie_count >= hpet_pie_limit) { 1455 rtc_int_flag |= RTC_PF; 1456 hpet_pie_count = 0; 1457 } 1458 1459 if (hpet_rtc_flags & RTC_AIE && 1460 (curr_time.tm_sec == hpet_alarm_time.tm_sec) && 1461 (curr_time.tm_min == hpet_alarm_time.tm_min) && 1462 (curr_time.tm_hour == hpet_alarm_time.tm_hour)) 1463 rtc_int_flag |= RTC_AF; 1464 1465 if (rtc_int_flag) { 1466 rtc_int_flag |= (RTC_IRQF | (RTC_NUM_INTS << 8)); 1467 if (irq_handler) 1468 irq_handler(rtc_int_flag, dev_id); 1469 } 1470 return IRQ_HANDLED; 1471 } 1472 EXPORT_SYMBOL_GPL(hpet_rtc_interrupt); 1473 #endif 1474