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1#include <linux/clocksource.h>
2#include <linux/clockchips.h>
3#include <linux/interrupt.h>
4#include <linux/export.h>
5#include <linux/delay.h>
6#include <linux/errno.h>
7#include <linux/i8253.h>
8#include <linux/slab.h>
9#include <linux/hpet.h>
10#include <linux/init.h>
11#include <linux/cpu.h>
12#include <linux/pm.h>
13#include <linux/io.h>
14
15#include <asm/fixmap.h>
16#include <asm/hpet.h>
17#include <asm/time.h>
18
19#define HPET_MASK CLOCKSOURCE_MASK(32)
20
21/* FSEC = 10^-15
22 NSEC = 10^-9 */
23#define FSEC_PER_NSEC 1000000L
24
25#define HPET_DEV_USED_BIT 2
26#define HPET_DEV_USED (1 << HPET_DEV_USED_BIT)
27#define HPET_DEV_VALID 0x8
28#define HPET_DEV_FSB_CAP 0x1000
29#define HPET_DEV_PERI_CAP 0x2000
30
31#define HPET_MIN_CYCLES 128
32#define HPET_MIN_PROG_DELTA (HPET_MIN_CYCLES + (HPET_MIN_CYCLES >> 1))
33
34/*
35 * HPET address is set in acpi/boot.c, when an ACPI entry exists
36 */
37unsigned long hpet_address;
38u8 hpet_blockid; /* OS timer block num */
39u8 hpet_msi_disable;
40
41#ifdef CONFIG_PCI_MSI
42static unsigned long hpet_num_timers;
43#endif
44static void __iomem *hpet_virt_address;
45
46struct hpet_dev {
47 struct clock_event_device evt;
48 unsigned int num;
49 int cpu;
50 unsigned int irq;
51 unsigned int flags;
52 char name[10];
53};
54
55inline struct hpet_dev *EVT_TO_HPET_DEV(struct clock_event_device *evtdev)
56{
57 return container_of(evtdev, struct hpet_dev, evt);
58}
59
60inline unsigned int hpet_readl(unsigned int a)
61{
62 return readl(hpet_virt_address + a);
63}
64
65static inline void hpet_writel(unsigned int d, unsigned int a)
66{
67 writel(d, hpet_virt_address + a);
68}
69
70#ifdef CONFIG_X86_64
71#include <asm/pgtable.h>
72#endif
73
74static inline void hpet_set_mapping(void)
75{
76 hpet_virt_address = ioremap_nocache(hpet_address, HPET_MMAP_SIZE);
77#ifdef CONFIG_X86_64
78 __set_fixmap(VSYSCALL_HPET, hpet_address, PAGE_KERNEL_VVAR_NOCACHE);
79#endif
80}
81
82static inline void hpet_clear_mapping(void)
83{
84 iounmap(hpet_virt_address);
85 hpet_virt_address = NULL;
86}
87
88/*
89 * HPET command line enable / disable
90 */
91int boot_hpet_disable;
92int hpet_force_user;
93static int hpet_verbose;
94
95static int __init hpet_setup(char *str)
96{
97 while (str) {
98 char *next = strchr(str, ',');
99
100 if (next)
101 *next++ = 0;
102 if (!strncmp("disable", str, 7))
103 boot_hpet_disable = 1;
104 if (!strncmp("force", str, 5))
105 hpet_force_user = 1;
106 if (!strncmp("verbose", str, 7))
107 hpet_verbose = 1;
108 str = next;
109 }
110 return 1;
111}
112__setup("hpet=", hpet_setup);
113
114static int __init disable_hpet(char *str)
115{
116 boot_hpet_disable = 1;
117 return 1;
118}
119__setup("nohpet", disable_hpet);
120
121static inline int is_hpet_capable(void)
122{
123 return !boot_hpet_disable && hpet_address;
124}
125
126/*
127 * HPET timer interrupt enable / disable
128 */
129static int hpet_legacy_int_enabled;
130
131/**
132 * is_hpet_enabled - check whether the hpet timer interrupt is enabled
133 */
134int is_hpet_enabled(void)
135{
136 return is_hpet_capable() && hpet_legacy_int_enabled;
137}
138EXPORT_SYMBOL_GPL(is_hpet_enabled);
139
140static void _hpet_print_config(const char *function, int line)
141{
142 u32 i, timers, l, h;
143 printk(KERN_INFO "hpet: %s(%d):\n", function, line);
144 l = hpet_readl(HPET_ID);
145 h = hpet_readl(HPET_PERIOD);
146 timers = ((l & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT) + 1;
147 printk(KERN_INFO "hpet: ID: 0x%x, PERIOD: 0x%x\n", l, h);
148 l = hpet_readl(HPET_CFG);
149 h = hpet_readl(HPET_STATUS);
150 printk(KERN_INFO "hpet: CFG: 0x%x, STATUS: 0x%x\n", l, h);
151 l = hpet_readl(HPET_COUNTER);
152 h = hpet_readl(HPET_COUNTER+4);
153 printk(KERN_INFO "hpet: COUNTER_l: 0x%x, COUNTER_h: 0x%x\n", l, h);
154
155 for (i = 0; i < timers; i++) {
156 l = hpet_readl(HPET_Tn_CFG(i));
157 h = hpet_readl(HPET_Tn_CFG(i)+4);
158 printk(KERN_INFO "hpet: T%d: CFG_l: 0x%x, CFG_h: 0x%x\n",
159 i, l, h);
160 l = hpet_readl(HPET_Tn_CMP(i));
161 h = hpet_readl(HPET_Tn_CMP(i)+4);
162 printk(KERN_INFO "hpet: T%d: CMP_l: 0x%x, CMP_h: 0x%x\n",
163 i, l, h);
164 l = hpet_readl(HPET_Tn_ROUTE(i));
165 h = hpet_readl(HPET_Tn_ROUTE(i)+4);
166 printk(KERN_INFO "hpet: T%d ROUTE_l: 0x%x, ROUTE_h: 0x%x\n",
167 i, l, h);
168 }
169}
170
171#define hpet_print_config() \
172do { \
173 if (hpet_verbose) \
174 _hpet_print_config(__FUNCTION__, __LINE__); \
175} while (0)
176
177/*
178 * When the hpet driver (/dev/hpet) is enabled, we need to reserve
179 * timer 0 and timer 1 in case of RTC emulation.
180 */
181#ifdef CONFIG_HPET
182
183static void hpet_reserve_msi_timers(struct hpet_data *hd);
184
185static void hpet_reserve_platform_timers(unsigned int id)
186{
187 struct hpet __iomem *hpet = hpet_virt_address;
188 struct hpet_timer __iomem *timer = &hpet->hpet_timers[2];
189 unsigned int nrtimers, i;
190 struct hpet_data hd;
191
192 nrtimers = ((id & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT) + 1;
193
194 memset(&hd, 0, sizeof(hd));
195 hd.hd_phys_address = hpet_address;
196 hd.hd_address = hpet;
197 hd.hd_nirqs = nrtimers;
198 hpet_reserve_timer(&hd, 0);
199
200#ifdef CONFIG_HPET_EMULATE_RTC
201 hpet_reserve_timer(&hd, 1);
202#endif
203
204 /*
205 * NOTE that hd_irq[] reflects IOAPIC input pins (LEGACY_8254
206 * is wrong for i8259!) not the output IRQ. Many BIOS writers
207 * don't bother configuring *any* comparator interrupts.
208 */
209 hd.hd_irq[0] = HPET_LEGACY_8254;
210 hd.hd_irq[1] = HPET_LEGACY_RTC;
211
212 for (i = 2; i < nrtimers; timer++, i++) {
213 hd.hd_irq[i] = (readl(&timer->hpet_config) &
214 Tn_INT_ROUTE_CNF_MASK) >> Tn_INT_ROUTE_CNF_SHIFT;
215 }
216
217 hpet_reserve_msi_timers(&hd);
218
219 hpet_alloc(&hd);
220
221}
222#else
223static void hpet_reserve_platform_timers(unsigned int id) { }
224#endif
225
226/*
227 * Common hpet info
228 */
229static unsigned long hpet_freq;
230
231static void hpet_legacy_set_mode(enum clock_event_mode mode,
232 struct clock_event_device *evt);
233static int hpet_legacy_next_event(unsigned long delta,
234 struct clock_event_device *evt);
235
236/*
237 * The hpet clock event device
238 */
239static struct clock_event_device hpet_clockevent = {
240 .name = "hpet",
241 .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
242 .set_mode = hpet_legacy_set_mode,
243 .set_next_event = hpet_legacy_next_event,
244 .irq = 0,
245 .rating = 50,
246};
247
248static void hpet_stop_counter(void)
249{
250 unsigned long cfg = hpet_readl(HPET_CFG);
251 cfg &= ~HPET_CFG_ENABLE;
252 hpet_writel(cfg, HPET_CFG);
253}
254
255static void hpet_reset_counter(void)
256{
257 hpet_writel(0, HPET_COUNTER);
258 hpet_writel(0, HPET_COUNTER + 4);
259}
260
261static void hpet_start_counter(void)
262{
263 unsigned int cfg = hpet_readl(HPET_CFG);
264 cfg |= HPET_CFG_ENABLE;
265 hpet_writel(cfg, HPET_CFG);
266}
267
268static void hpet_restart_counter(void)
269{
270 hpet_stop_counter();
271 hpet_reset_counter();
272 hpet_start_counter();
273}
274
275static void hpet_resume_device(void)
276{
277 force_hpet_resume();
278}
279
280static void hpet_resume_counter(struct clocksource *cs)
281{
282 hpet_resume_device();
283 hpet_restart_counter();
284}
285
286static void hpet_enable_legacy_int(void)
287{
288 unsigned int cfg = hpet_readl(HPET_CFG);
289
290 cfg |= HPET_CFG_LEGACY;
291 hpet_writel(cfg, HPET_CFG);
292 hpet_legacy_int_enabled = 1;
293}
294
295static void hpet_legacy_clockevent_register(void)
296{
297 /* Start HPET legacy interrupts */
298 hpet_enable_legacy_int();
299
300 /*
301 * Start hpet with the boot cpu mask and make it
302 * global after the IO_APIC has been initialized.
303 */
304 hpet_clockevent.cpumask = cpumask_of(smp_processor_id());
305 clockevents_config_and_register(&hpet_clockevent, hpet_freq,
306 HPET_MIN_PROG_DELTA, 0x7FFFFFFF);
307 global_clock_event = &hpet_clockevent;
308 printk(KERN_DEBUG "hpet clockevent registered\n");
309}
310
311static int hpet_setup_msi_irq(unsigned int irq);
312
313static void hpet_set_mode(enum clock_event_mode mode,
314 struct clock_event_device *evt, int timer)
315{
316 unsigned int cfg, cmp, now;
317 uint64_t delta;
318
319 switch (mode) {
320 case CLOCK_EVT_MODE_PERIODIC:
321 hpet_stop_counter();
322 delta = ((uint64_t)(NSEC_PER_SEC/HZ)) * evt->mult;
323 delta >>= evt->shift;
324 now = hpet_readl(HPET_COUNTER);
325 cmp = now + (unsigned int) delta;
326 cfg = hpet_readl(HPET_Tn_CFG(timer));
327 cfg |= HPET_TN_ENABLE | HPET_TN_PERIODIC |
328 HPET_TN_SETVAL | HPET_TN_32BIT;
329 hpet_writel(cfg, HPET_Tn_CFG(timer));
330 hpet_writel(cmp, HPET_Tn_CMP(timer));
331 udelay(1);
332 /*
333 * HPET on AMD 81xx needs a second write (with HPET_TN_SETVAL
334 * cleared) to T0_CMP to set the period. The HPET_TN_SETVAL
335 * bit is automatically cleared after the first write.
336 * (See AMD-8111 HyperTransport I/O Hub Data Sheet,
337 * Publication # 24674)
338 */
339 hpet_writel((unsigned int) delta, HPET_Tn_CMP(timer));
340 hpet_start_counter();
341 hpet_print_config();
342 break;
343
344 case CLOCK_EVT_MODE_ONESHOT:
345 cfg = hpet_readl(HPET_Tn_CFG(timer));
346 cfg &= ~HPET_TN_PERIODIC;
347 cfg |= HPET_TN_ENABLE | HPET_TN_32BIT;
348 hpet_writel(cfg, HPET_Tn_CFG(timer));
349 break;
350
351 case CLOCK_EVT_MODE_UNUSED:
352 case CLOCK_EVT_MODE_SHUTDOWN:
353 cfg = hpet_readl(HPET_Tn_CFG(timer));
354 cfg &= ~HPET_TN_ENABLE;
355 hpet_writel(cfg, HPET_Tn_CFG(timer));
356 break;
357
358 case CLOCK_EVT_MODE_RESUME:
359 if (timer == 0) {
360 hpet_enable_legacy_int();
361 } else {
362 struct hpet_dev *hdev = EVT_TO_HPET_DEV(evt);
363 hpet_setup_msi_irq(hdev->irq);
364 disable_irq(hdev->irq);
365 irq_set_affinity(hdev->irq, cpumask_of(hdev->cpu));
366 enable_irq(hdev->irq);
367 }
368 hpet_print_config();
369 break;
370 }
371}
372
373static int hpet_next_event(unsigned long delta,
374 struct clock_event_device *evt, int timer)
375{
376 u32 cnt;
377 s32 res;
378
379 cnt = hpet_readl(HPET_COUNTER);
380 cnt += (u32) delta;
381 hpet_writel(cnt, HPET_Tn_CMP(timer));
382
383 /*
384 * HPETs are a complete disaster. The compare register is
385 * based on a equal comparison and neither provides a less
386 * than or equal functionality (which would require to take
387 * the wraparound into account) nor a simple count down event
388 * mode. Further the write to the comparator register is
389 * delayed internally up to two HPET clock cycles in certain
390 * chipsets (ATI, ICH9,10). Some newer AMD chipsets have even
391 * longer delays. We worked around that by reading back the
392 * compare register, but that required another workaround for
393 * ICH9,10 chips where the first readout after write can
394 * return the old stale value. We already had a minimum
395 * programming delta of 5us enforced, but a NMI or SMI hitting
396 * between the counter readout and the comparator write can
397 * move us behind that point easily. Now instead of reading
398 * the compare register back several times, we make the ETIME
399 * decision based on the following: Return ETIME if the
400 * counter value after the write is less than HPET_MIN_CYCLES
401 * away from the event or if the counter is already ahead of
402 * the event. The minimum programming delta for the generic
403 * clockevents code is set to 1.5 * HPET_MIN_CYCLES.
404 */
405 res = (s32)(cnt - hpet_readl(HPET_COUNTER));
406
407 return res < HPET_MIN_CYCLES ? -ETIME : 0;
408}
409
410static void hpet_legacy_set_mode(enum clock_event_mode mode,
411 struct clock_event_device *evt)
412{
413 hpet_set_mode(mode, evt, 0);
414}
415
416static int hpet_legacy_next_event(unsigned long delta,
417 struct clock_event_device *evt)
418{
419 return hpet_next_event(delta, evt, 0);
420}
421
422/*
423 * HPET MSI Support
424 */
425#ifdef CONFIG_PCI_MSI
426
427static DEFINE_PER_CPU(struct hpet_dev *, cpu_hpet_dev);
428static struct hpet_dev *hpet_devs;
429
430void hpet_msi_unmask(struct irq_data *data)
431{
432 struct hpet_dev *hdev = data->handler_data;
433 unsigned int cfg;
434
435 /* unmask it */
436 cfg = hpet_readl(HPET_Tn_CFG(hdev->num));
437 cfg |= HPET_TN_ENABLE | HPET_TN_FSB;
438 hpet_writel(cfg, HPET_Tn_CFG(hdev->num));
439}
440
441void hpet_msi_mask(struct irq_data *data)
442{
443 struct hpet_dev *hdev = data->handler_data;
444 unsigned int cfg;
445
446 /* mask it */
447 cfg = hpet_readl(HPET_Tn_CFG(hdev->num));
448 cfg &= ~(HPET_TN_ENABLE | HPET_TN_FSB);
449 hpet_writel(cfg, HPET_Tn_CFG(hdev->num));
450}
451
452void hpet_msi_write(struct hpet_dev *hdev, struct msi_msg *msg)
453{
454 hpet_writel(msg->data, HPET_Tn_ROUTE(hdev->num));
455 hpet_writel(msg->address_lo, HPET_Tn_ROUTE(hdev->num) + 4);
456}
457
458void hpet_msi_read(struct hpet_dev *hdev, struct msi_msg *msg)
459{
460 msg->data = hpet_readl(HPET_Tn_ROUTE(hdev->num));
461 msg->address_lo = hpet_readl(HPET_Tn_ROUTE(hdev->num) + 4);
462 msg->address_hi = 0;
463}
464
465static void hpet_msi_set_mode(enum clock_event_mode mode,
466 struct clock_event_device *evt)
467{
468 struct hpet_dev *hdev = EVT_TO_HPET_DEV(evt);
469 hpet_set_mode(mode, evt, hdev->num);
470}
471
472static int hpet_msi_next_event(unsigned long delta,
473 struct clock_event_device *evt)
474{
475 struct hpet_dev *hdev = EVT_TO_HPET_DEV(evt);
476 return hpet_next_event(delta, evt, hdev->num);
477}
478
479static int hpet_setup_msi_irq(unsigned int irq)
480{
481 if (x86_msi.setup_hpet_msi(irq, hpet_blockid)) {
482 destroy_irq(irq);
483 return -EINVAL;
484 }
485 return 0;
486}
487
488static int hpet_assign_irq(struct hpet_dev *dev)
489{
490 unsigned int irq;
491
492 irq = create_irq_nr(0, -1);
493 if (!irq)
494 return -EINVAL;
495
496 irq_set_handler_data(irq, dev);
497
498 if (hpet_setup_msi_irq(irq))
499 return -EINVAL;
500
501 dev->irq = irq;
502 return 0;
503}
504
505static irqreturn_t hpet_interrupt_handler(int irq, void *data)
506{
507 struct hpet_dev *dev = (struct hpet_dev *)data;
508 struct clock_event_device *hevt = &dev->evt;
509
510 if (!hevt->event_handler) {
511 printk(KERN_INFO "Spurious HPET timer interrupt on HPET timer %d\n",
512 dev->num);
513 return IRQ_HANDLED;
514 }
515
516 hevt->event_handler(hevt);
517 return IRQ_HANDLED;
518}
519
520static int hpet_setup_irq(struct hpet_dev *dev)
521{
522
523 if (request_irq(dev->irq, hpet_interrupt_handler,
524 IRQF_TIMER | IRQF_NOBALANCING,
525 dev->name, dev))
526 return -1;
527
528 disable_irq(dev->irq);
529 irq_set_affinity(dev->irq, cpumask_of(dev->cpu));
530 enable_irq(dev->irq);
531
532 printk(KERN_DEBUG "hpet: %s irq %d for MSI\n",
533 dev->name, dev->irq);
534
535 return 0;
536}
537
538/* This should be called in specific @cpu */
539static void init_one_hpet_msi_clockevent(struct hpet_dev *hdev, int cpu)
540{
541 struct clock_event_device *evt = &hdev->evt;
542
543 WARN_ON(cpu != smp_processor_id());
544 if (!(hdev->flags & HPET_DEV_VALID))
545 return;
546
547 if (hpet_setup_msi_irq(hdev->irq))
548 return;
549
550 hdev->cpu = cpu;
551 per_cpu(cpu_hpet_dev, cpu) = hdev;
552 evt->name = hdev->name;
553 hpet_setup_irq(hdev);
554 evt->irq = hdev->irq;
555
556 evt->rating = 110;
557 evt->features = CLOCK_EVT_FEAT_ONESHOT;
558 if (hdev->flags & HPET_DEV_PERI_CAP)
559 evt->features |= CLOCK_EVT_FEAT_PERIODIC;
560
561 evt->set_mode = hpet_msi_set_mode;
562 evt->set_next_event = hpet_msi_next_event;
563 evt->cpumask = cpumask_of(hdev->cpu);
564
565 clockevents_config_and_register(evt, hpet_freq, HPET_MIN_PROG_DELTA,
566 0x7FFFFFFF);
567}
568
569#ifdef CONFIG_HPET
570/* Reserve at least one timer for userspace (/dev/hpet) */
571#define RESERVE_TIMERS 1
572#else
573#define RESERVE_TIMERS 0
574#endif
575
576static void hpet_msi_capability_lookup(unsigned int start_timer)
577{
578 unsigned int id;
579 unsigned int num_timers;
580 unsigned int num_timers_used = 0;
581 int i;
582
583 if (hpet_msi_disable)
584 return;
585
586 if (boot_cpu_has(X86_FEATURE_ARAT))
587 return;
588 id = hpet_readl(HPET_ID);
589
590 num_timers = ((id & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT);
591 num_timers++; /* Value read out starts from 0 */
592 hpet_print_config();
593
594 hpet_devs = kzalloc(sizeof(struct hpet_dev) * num_timers, GFP_KERNEL);
595 if (!hpet_devs)
596 return;
597
598 hpet_num_timers = num_timers;
599
600 for (i = start_timer; i < num_timers - RESERVE_TIMERS; i++) {
601 struct hpet_dev *hdev = &hpet_devs[num_timers_used];
602 unsigned int cfg = hpet_readl(HPET_Tn_CFG(i));
603
604 /* Only consider HPET timer with MSI support */
605 if (!(cfg & HPET_TN_FSB_CAP))
606 continue;
607
608 hdev->flags = 0;
609 if (cfg & HPET_TN_PERIODIC_CAP)
610 hdev->flags |= HPET_DEV_PERI_CAP;
611 hdev->num = i;
612
613 sprintf(hdev->name, "hpet%d", i);
614 if (hpet_assign_irq(hdev))
615 continue;
616
617 hdev->flags |= HPET_DEV_FSB_CAP;
618 hdev->flags |= HPET_DEV_VALID;
619 num_timers_used++;
620 if (num_timers_used == num_possible_cpus())
621 break;
622 }
623
624 printk(KERN_INFO "HPET: %d timers in total, %d timers will be used for per-cpu timer\n",
625 num_timers, num_timers_used);
626}
627
628#ifdef CONFIG_HPET
629static void hpet_reserve_msi_timers(struct hpet_data *hd)
630{
631 int i;
632
633 if (!hpet_devs)
634 return;
635
636 for (i = 0; i < hpet_num_timers; i++) {
637 struct hpet_dev *hdev = &hpet_devs[i];
638
639 if (!(hdev->flags & HPET_DEV_VALID))
640 continue;
641
642 hd->hd_irq[hdev->num] = hdev->irq;
643 hpet_reserve_timer(hd, hdev->num);
644 }
645}
646#endif
647
648static struct hpet_dev *hpet_get_unused_timer(void)
649{
650 int i;
651
652 if (!hpet_devs)
653 return NULL;
654
655 for (i = 0; i < hpet_num_timers; i++) {
656 struct hpet_dev *hdev = &hpet_devs[i];
657
658 if (!(hdev->flags & HPET_DEV_VALID))
659 continue;
660 if (test_and_set_bit(HPET_DEV_USED_BIT,
661 (unsigned long *)&hdev->flags))
662 continue;
663 return hdev;
664 }
665 return NULL;
666}
667
668struct hpet_work_struct {
669 struct delayed_work work;
670 struct completion complete;
671};
672
673static void hpet_work(struct work_struct *w)
674{
675 struct hpet_dev *hdev;
676 int cpu = smp_processor_id();
677 struct hpet_work_struct *hpet_work;
678
679 hpet_work = container_of(w, struct hpet_work_struct, work.work);
680
681 hdev = hpet_get_unused_timer();
682 if (hdev)
683 init_one_hpet_msi_clockevent(hdev, cpu);
684
685 complete(&hpet_work->complete);
686}
687
688static int hpet_cpuhp_notify(struct notifier_block *n,
689 unsigned long action, void *hcpu)
690{
691 unsigned long cpu = (unsigned long)hcpu;
692 struct hpet_work_struct work;
693 struct hpet_dev *hdev = per_cpu(cpu_hpet_dev, cpu);
694
695 switch (action & 0xf) {
696 case CPU_ONLINE:
697 INIT_DELAYED_WORK_ONSTACK(&work.work, hpet_work);
698 init_completion(&work.complete);
699 /* FIXME: add schedule_work_on() */
700 schedule_delayed_work_on(cpu, &work.work, 0);
701 wait_for_completion(&work.complete);
702 destroy_delayed_work_on_stack(&work.work);
703 break;
704 case CPU_DEAD:
705 if (hdev) {
706 free_irq(hdev->irq, hdev);
707 hdev->flags &= ~HPET_DEV_USED;
708 per_cpu(cpu_hpet_dev, cpu) = NULL;
709 }
710 break;
711 }
712 return NOTIFY_OK;
713}
714#else
715
716static int hpet_setup_msi_irq(unsigned int irq)
717{
718 return 0;
719}
720static void hpet_msi_capability_lookup(unsigned int start_timer)
721{
722 return;
723}
724
725#ifdef CONFIG_HPET
726static void hpet_reserve_msi_timers(struct hpet_data *hd)
727{
728 return;
729}
730#endif
731
732static int hpet_cpuhp_notify(struct notifier_block *n,
733 unsigned long action, void *hcpu)
734{
735 return NOTIFY_OK;
736}
737
738#endif
739
740/*
741 * Clock source related code
742 */
743static cycle_t read_hpet(struct clocksource *cs)
744{
745 return (cycle_t)hpet_readl(HPET_COUNTER);
746}
747
748static struct clocksource clocksource_hpet = {
749 .name = "hpet",
750 .rating = 250,
751 .read = read_hpet,
752 .mask = HPET_MASK,
753 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
754 .resume = hpet_resume_counter,
755 .archdata = { .vclock_mode = VCLOCK_HPET },
756};
757
758static int hpet_clocksource_register(void)
759{
760 u64 start, now;
761 cycle_t t1;
762
763 /* Start the counter */
764 hpet_restart_counter();
765
766 /* Verify whether hpet counter works */
767 t1 = hpet_readl(HPET_COUNTER);
768 rdtscll(start);
769
770 /*
771 * We don't know the TSC frequency yet, but waiting for
772 * 200000 TSC cycles is safe:
773 * 4 GHz == 50us
774 * 1 GHz == 200us
775 */
776 do {
777 rep_nop();
778 rdtscll(now);
779 } while ((now - start) < 200000UL);
780
781 if (t1 == hpet_readl(HPET_COUNTER)) {
782 printk(KERN_WARNING
783 "HPET counter not counting. HPET disabled\n");
784 return -ENODEV;
785 }
786
787 clocksource_register_hz(&clocksource_hpet, (u32)hpet_freq);
788 return 0;
789}
790
791static u32 *hpet_boot_cfg;
792
793/**
794 * hpet_enable - Try to setup the HPET timer. Returns 1 on success.
795 */
796int __init hpet_enable(void)
797{
798 u32 hpet_period, cfg, id;
799 u64 freq;
800 unsigned int i, last;
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 * The period is a femto seconds value. Convert it to a
839 * frequency.
840 */
841 freq = FSEC_PER_SEC;
842 do_div(freq, hpet_period);
843 hpet_freq = freq;
844
845 /*
846 * Read the HPET ID register to retrieve the IRQ routing
847 * information and the number of channels
848 */
849 id = hpet_readl(HPET_ID);
850 hpet_print_config();
851
852 last = (id & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT;
853
854#ifdef CONFIG_HPET_EMULATE_RTC
855 /*
856 * The legacy routing mode needs at least two channels, tick timer
857 * and the rtc emulation channel.
858 */
859 if (!last)
860 goto out_nohpet;
861#endif
862
863 cfg = hpet_readl(HPET_CFG);
864 hpet_boot_cfg = kmalloc((last + 2) * sizeof(*hpet_boot_cfg),
865 GFP_KERNEL);
866 if (hpet_boot_cfg)
867 *hpet_boot_cfg = cfg;
868 else
869 pr_warn("HPET initial state will not be saved\n");
870 cfg &= ~(HPET_CFG_ENABLE | HPET_CFG_LEGACY);
871 hpet_writel(cfg, HPET_CFG);
872 if (cfg)
873 pr_warn("HPET: Unrecognized bits %#x set in global cfg\n",
874 cfg);
875
876 for (i = 0; i <= last; ++i) {
877 cfg = hpet_readl(HPET_Tn_CFG(i));
878 if (hpet_boot_cfg)
879 hpet_boot_cfg[i + 1] = cfg;
880 cfg &= ~(HPET_TN_ENABLE | HPET_TN_LEVEL | HPET_TN_FSB);
881 hpet_writel(cfg, HPET_Tn_CFG(i));
882 cfg &= ~(HPET_TN_PERIODIC | HPET_TN_PERIODIC_CAP
883 | HPET_TN_64BIT_CAP | HPET_TN_32BIT | HPET_TN_ROUTE
884 | HPET_TN_FSB | HPET_TN_FSB_CAP);
885 if (cfg)
886 pr_warn("HPET: Unrecognized bits %#x set in cfg#%u\n",
887 cfg, i);
888 }
889 hpet_print_config();
890
891 if (hpet_clocksource_register())
892 goto out_nohpet;
893
894 if (id & HPET_ID_LEGSUP) {
895 hpet_legacy_clockevent_register();
896 return 1;
897 }
898 return 0;
899
900out_nohpet:
901 hpet_clear_mapping();
902 hpet_address = 0;
903 return 0;
904}
905
906/*
907 * Needs to be late, as the reserve_timer code calls kalloc !
908 *
909 * Not a problem on i386 as hpet_enable is called from late_time_init,
910 * but on x86_64 it is necessary !
911 */
912static __init int hpet_late_init(void)
913{
914 int cpu;
915
916 if (boot_hpet_disable)
917 return -ENODEV;
918
919 if (!hpet_address) {
920 if (!force_hpet_address)
921 return -ENODEV;
922
923 hpet_address = force_hpet_address;
924 hpet_enable();
925 }
926
927 if (!hpet_virt_address)
928 return -ENODEV;
929
930 if (hpet_readl(HPET_ID) & HPET_ID_LEGSUP)
931 hpet_msi_capability_lookup(2);
932 else
933 hpet_msi_capability_lookup(0);
934
935 hpet_reserve_platform_timers(hpet_readl(HPET_ID));
936 hpet_print_config();
937
938 if (hpet_msi_disable)
939 return 0;
940
941 if (boot_cpu_has(X86_FEATURE_ARAT))
942 return 0;
943
944 cpu_notifier_register_begin();
945 for_each_online_cpu(cpu) {
946 hpet_cpuhp_notify(NULL, CPU_ONLINE, (void *)(long)cpu);
947 }
948
949 /* This notifier should be called after workqueue is ready */
950 __hotcpu_notifier(hpet_cpuhp_notify, -20);
951 cpu_notifier_register_done();
952
953 return 0;
954}
955fs_initcall(hpet_late_init);
956
957void hpet_disable(void)
958{
959 if (is_hpet_capable() && hpet_virt_address) {
960 unsigned int cfg = hpet_readl(HPET_CFG), id, last;
961
962 if (hpet_boot_cfg)
963 cfg = *hpet_boot_cfg;
964 else if (hpet_legacy_int_enabled) {
965 cfg &= ~HPET_CFG_LEGACY;
966 hpet_legacy_int_enabled = 0;
967 }
968 cfg &= ~HPET_CFG_ENABLE;
969 hpet_writel(cfg, HPET_CFG);
970
971 if (!hpet_boot_cfg)
972 return;
973
974 id = hpet_readl(HPET_ID);
975 last = ((id & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT);
976
977 for (id = 0; id <= last; ++id)
978 hpet_writel(hpet_boot_cfg[id + 1], HPET_Tn_CFG(id));
979
980 if (*hpet_boot_cfg & HPET_CFG_ENABLE)
981 hpet_writel(*hpet_boot_cfg, HPET_CFG);
982 }
983}
984
985#ifdef CONFIG_HPET_EMULATE_RTC
986
987/* HPET in LegacyReplacement Mode eats up RTC interrupt line. When, HPET
988 * is enabled, we support RTC interrupt functionality in software.
989 * RTC has 3 kinds of interrupts:
990 * 1) Update Interrupt - generate an interrupt, every sec, when RTC clock
991 * is updated
992 * 2) Alarm Interrupt - generate an interrupt at a specific time of day
993 * 3) Periodic Interrupt - generate periodic interrupt, with frequencies
994 * 2Hz-8192Hz (2Hz-64Hz for non-root user) (all freqs in powers of 2)
995 * (1) and (2) above are implemented using polling at a frequency of
996 * 64 Hz. The exact frequency is a tradeoff between accuracy and interrupt
997 * overhead. (DEFAULT_RTC_INT_FREQ)
998 * For (3), we use interrupts at 64Hz or user specified periodic
999 * frequency, whichever is higher.
1000 */
1001#include <linux/mc146818rtc.h>
1002#include <linux/rtc.h>
1003#include <asm/rtc.h>
1004
1005#define DEFAULT_RTC_INT_FREQ 64
1006#define DEFAULT_RTC_SHIFT 6
1007#define RTC_NUM_INTS 1
1008
1009static unsigned long hpet_rtc_flags;
1010static int hpet_prev_update_sec;
1011static struct rtc_time hpet_alarm_time;
1012static unsigned long hpet_pie_count;
1013static u32 hpet_t1_cmp;
1014static u32 hpet_default_delta;
1015static u32 hpet_pie_delta;
1016static unsigned long hpet_pie_limit;
1017
1018static rtc_irq_handler irq_handler;
1019
1020/*
1021 * Check that the hpet counter c1 is ahead of the c2
1022 */
1023static inline int hpet_cnt_ahead(u32 c1, u32 c2)
1024{
1025 return (s32)(c2 - c1) < 0;
1026}
1027
1028/*
1029 * Registers a IRQ handler.
1030 */
1031int hpet_register_irq_handler(rtc_irq_handler handler)
1032{
1033 if (!is_hpet_enabled())
1034 return -ENODEV;
1035 if (irq_handler)
1036 return -EBUSY;
1037
1038 irq_handler = handler;
1039
1040 return 0;
1041}
1042EXPORT_SYMBOL_GPL(hpet_register_irq_handler);
1043
1044/*
1045 * Deregisters the IRQ handler registered with hpet_register_irq_handler()
1046 * and does cleanup.
1047 */
1048void hpet_unregister_irq_handler(rtc_irq_handler handler)
1049{
1050 if (!is_hpet_enabled())
1051 return;
1052
1053 irq_handler = NULL;
1054 hpet_rtc_flags = 0;
1055}
1056EXPORT_SYMBOL_GPL(hpet_unregister_irq_handler);
1057
1058/*
1059 * Timer 1 for RTC emulation. We use one shot mode, as periodic mode
1060 * is not supported by all HPET implementations for timer 1.
1061 *
1062 * hpet_rtc_timer_init() is called when the rtc is initialized.
1063 */
1064int hpet_rtc_timer_init(void)
1065{
1066 unsigned int cfg, cnt, delta;
1067 unsigned long flags;
1068
1069 if (!is_hpet_enabled())
1070 return 0;
1071
1072 if (!hpet_default_delta) {
1073 uint64_t clc;
1074
1075 clc = (uint64_t) hpet_clockevent.mult * NSEC_PER_SEC;
1076 clc >>= hpet_clockevent.shift + DEFAULT_RTC_SHIFT;
1077 hpet_default_delta = clc;
1078 }
1079
1080 if (!(hpet_rtc_flags & RTC_PIE) || hpet_pie_limit)
1081 delta = hpet_default_delta;
1082 else
1083 delta = hpet_pie_delta;
1084
1085 local_irq_save(flags);
1086
1087 cnt = delta + hpet_readl(HPET_COUNTER);
1088 hpet_writel(cnt, HPET_T1_CMP);
1089 hpet_t1_cmp = cnt;
1090
1091 cfg = hpet_readl(HPET_T1_CFG);
1092 cfg &= ~HPET_TN_PERIODIC;
1093 cfg |= HPET_TN_ENABLE | HPET_TN_32BIT;
1094 hpet_writel(cfg, HPET_T1_CFG);
1095
1096 local_irq_restore(flags);
1097
1098 return 1;
1099}
1100EXPORT_SYMBOL_GPL(hpet_rtc_timer_init);
1101
1102static void hpet_disable_rtc_channel(void)
1103{
1104 unsigned long cfg;
1105 cfg = hpet_readl(HPET_T1_CFG);
1106 cfg &= ~HPET_TN_ENABLE;
1107 hpet_writel(cfg, HPET_T1_CFG);
1108}
1109
1110/*
1111 * The functions below are called from rtc driver.
1112 * Return 0 if HPET is not being used.
1113 * Otherwise do the necessary changes and return 1.
1114 */
1115int hpet_mask_rtc_irq_bit(unsigned long bit_mask)
1116{
1117 if (!is_hpet_enabled())
1118 return 0;
1119
1120 hpet_rtc_flags &= ~bit_mask;
1121 if (unlikely(!hpet_rtc_flags))
1122 hpet_disable_rtc_channel();
1123
1124 return 1;
1125}
1126EXPORT_SYMBOL_GPL(hpet_mask_rtc_irq_bit);
1127
1128int hpet_set_rtc_irq_bit(unsigned long bit_mask)
1129{
1130 unsigned long oldbits = hpet_rtc_flags;
1131
1132 if (!is_hpet_enabled())
1133 return 0;
1134
1135 hpet_rtc_flags |= bit_mask;
1136
1137 if ((bit_mask & RTC_UIE) && !(oldbits & RTC_UIE))
1138 hpet_prev_update_sec = -1;
1139
1140 if (!oldbits)
1141 hpet_rtc_timer_init();
1142
1143 return 1;
1144}
1145EXPORT_SYMBOL_GPL(hpet_set_rtc_irq_bit);
1146
1147int hpet_set_alarm_time(unsigned char hrs, unsigned char min,
1148 unsigned char sec)
1149{
1150 if (!is_hpet_enabled())
1151 return 0;
1152
1153 hpet_alarm_time.tm_hour = hrs;
1154 hpet_alarm_time.tm_min = min;
1155 hpet_alarm_time.tm_sec = sec;
1156
1157 return 1;
1158}
1159EXPORT_SYMBOL_GPL(hpet_set_alarm_time);
1160
1161int hpet_set_periodic_freq(unsigned long freq)
1162{
1163 uint64_t clc;
1164
1165 if (!is_hpet_enabled())
1166 return 0;
1167
1168 if (freq <= DEFAULT_RTC_INT_FREQ)
1169 hpet_pie_limit = DEFAULT_RTC_INT_FREQ / freq;
1170 else {
1171 clc = (uint64_t) hpet_clockevent.mult * NSEC_PER_SEC;
1172 do_div(clc, freq);
1173 clc >>= hpet_clockevent.shift;
1174 hpet_pie_delta = clc;
1175 hpet_pie_limit = 0;
1176 }
1177 return 1;
1178}
1179EXPORT_SYMBOL_GPL(hpet_set_periodic_freq);
1180
1181int hpet_rtc_dropped_irq(void)
1182{
1183 return is_hpet_enabled();
1184}
1185EXPORT_SYMBOL_GPL(hpet_rtc_dropped_irq);
1186
1187static void hpet_rtc_timer_reinit(void)
1188{
1189 unsigned int delta;
1190 int lost_ints = -1;
1191
1192 if (unlikely(!hpet_rtc_flags))
1193 hpet_disable_rtc_channel();
1194
1195 if (!(hpet_rtc_flags & RTC_PIE) || hpet_pie_limit)
1196 delta = hpet_default_delta;
1197 else
1198 delta = hpet_pie_delta;
1199
1200 /*
1201 * Increment the comparator value until we are ahead of the
1202 * current count.
1203 */
1204 do {
1205 hpet_t1_cmp += delta;
1206 hpet_writel(hpet_t1_cmp, HPET_T1_CMP);
1207 lost_ints++;
1208 } while (!hpet_cnt_ahead(hpet_t1_cmp, hpet_readl(HPET_COUNTER)));
1209
1210 if (lost_ints) {
1211 if (hpet_rtc_flags & RTC_PIE)
1212 hpet_pie_count += lost_ints;
1213 if (printk_ratelimit())
1214 printk(KERN_WARNING "hpet1: lost %d rtc interrupts\n",
1215 lost_ints);
1216 }
1217}
1218
1219irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id)
1220{
1221 struct rtc_time curr_time;
1222 unsigned long rtc_int_flag = 0;
1223
1224 hpet_rtc_timer_reinit();
1225 memset(&curr_time, 0, sizeof(struct rtc_time));
1226
1227 if (hpet_rtc_flags & (RTC_UIE | RTC_AIE))
1228 get_rtc_time(&curr_time);
1229
1230 if (hpet_rtc_flags & RTC_UIE &&
1231 curr_time.tm_sec != hpet_prev_update_sec) {
1232 if (hpet_prev_update_sec >= 0)
1233 rtc_int_flag = RTC_UF;
1234 hpet_prev_update_sec = curr_time.tm_sec;
1235 }
1236
1237 if (hpet_rtc_flags & RTC_PIE &&
1238 ++hpet_pie_count >= hpet_pie_limit) {
1239 rtc_int_flag |= RTC_PF;
1240 hpet_pie_count = 0;
1241 }
1242
1243 if (hpet_rtc_flags & RTC_AIE &&
1244 (curr_time.tm_sec == hpet_alarm_time.tm_sec) &&
1245 (curr_time.tm_min == hpet_alarm_time.tm_min) &&
1246 (curr_time.tm_hour == hpet_alarm_time.tm_hour))
1247 rtc_int_flag |= RTC_AF;
1248
1249 if (rtc_int_flag) {
1250 rtc_int_flag |= (RTC_IRQF | (RTC_NUM_INTS << 8));
1251 if (irq_handler)
1252 irq_handler(rtc_int_flag, dev_id);
1253 }
1254 return IRQ_HANDLED;
1255}
1256EXPORT_SYMBOL_GPL(hpet_rtc_interrupt);
1257#endif
1#include <linux/clocksource.h>
2#include <linux/clockchips.h>
3#include <linux/interrupt.h>
4#include <linux/export.h>
5#include <linux/delay.h>
6#include <linux/errno.h>
7#include <linux/i8253.h>
8#include <linux/slab.h>
9#include <linux/hpet.h>
10#include <linux/init.h>
11#include <linux/cpu.h>
12#include <linux/pm.h>
13#include <linux/io.h>
14
15#include <asm/cpufeature.h>
16#include <asm/irqdomain.h>
17#include <asm/fixmap.h>
18#include <asm/hpet.h>
19#include <asm/time.h>
20
21#define HPET_MASK CLOCKSOURCE_MASK(32)
22
23/* FSEC = 10^-15
24 NSEC = 10^-9 */
25#define FSEC_PER_NSEC 1000000L
26
27#define HPET_DEV_USED_BIT 2
28#define HPET_DEV_USED (1 << HPET_DEV_USED_BIT)
29#define HPET_DEV_VALID 0x8
30#define HPET_DEV_FSB_CAP 0x1000
31#define HPET_DEV_PERI_CAP 0x2000
32
33#define HPET_MIN_CYCLES 128
34#define HPET_MIN_PROG_DELTA (HPET_MIN_CYCLES + (HPET_MIN_CYCLES >> 1))
35
36/*
37 * HPET address is set in acpi/boot.c, when an ACPI entry exists
38 */
39unsigned long hpet_address;
40u8 hpet_blockid; /* OS timer block num */
41bool hpet_msi_disable;
42
43#ifdef CONFIG_PCI_MSI
44static unsigned int hpet_num_timers;
45#endif
46static void __iomem *hpet_virt_address;
47
48struct hpet_dev {
49 struct clock_event_device evt;
50 unsigned int num;
51 int cpu;
52 unsigned int irq;
53 unsigned int flags;
54 char name[10];
55};
56
57static inline struct hpet_dev *EVT_TO_HPET_DEV(struct clock_event_device *evtdev)
58{
59 return container_of(evtdev, struct hpet_dev, evt);
60}
61
62inline unsigned int hpet_readl(unsigned int a)
63{
64 return readl(hpet_virt_address + a);
65}
66
67static inline void hpet_writel(unsigned int d, unsigned int a)
68{
69 writel(d, hpet_virt_address + a);
70}
71
72#ifdef CONFIG_X86_64
73#include <asm/pgtable.h>
74#endif
75
76static inline void hpet_set_mapping(void)
77{
78 hpet_virt_address = ioremap_nocache(hpet_address, HPET_MMAP_SIZE);
79}
80
81static inline void hpet_clear_mapping(void)
82{
83 iounmap(hpet_virt_address);
84 hpet_virt_address = NULL;
85}
86
87/*
88 * HPET command line enable / disable
89 */
90bool boot_hpet_disable;
91bool hpet_force_user;
92static bool hpet_verbose;
93
94static int __init hpet_setup(char *str)
95{
96 while (str) {
97 char *next = strchr(str, ',');
98
99 if (next)
100 *next++ = 0;
101 if (!strncmp("disable", str, 7))
102 boot_hpet_disable = true;
103 if (!strncmp("force", str, 5))
104 hpet_force_user = true;
105 if (!strncmp("verbose", str, 7))
106 hpet_verbose = true;
107 str = next;
108 }
109 return 1;
110}
111__setup("hpet=", hpet_setup);
112
113static int __init disable_hpet(char *str)
114{
115 boot_hpet_disable = true;
116 return 1;
117}
118__setup("nohpet", disable_hpet);
119
120static inline int is_hpet_capable(void)
121{
122 return !boot_hpet_disable && hpet_address;
123}
124
125/*
126 * HPET timer interrupt enable / disable
127 */
128static bool hpet_legacy_int_enabled;
129
130/**
131 * is_hpet_enabled - check whether the hpet timer interrupt is enabled
132 */
133int is_hpet_enabled(void)
134{
135 return is_hpet_capable() && hpet_legacy_int_enabled;
136}
137EXPORT_SYMBOL_GPL(is_hpet_enabled);
138
139static void _hpet_print_config(const char *function, int line)
140{
141 u32 i, timers, l, h;
142 printk(KERN_INFO "hpet: %s(%d):\n", function, line);
143 l = hpet_readl(HPET_ID);
144 h = hpet_readl(HPET_PERIOD);
145 timers = ((l & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT) + 1;
146 printk(KERN_INFO "hpet: ID: 0x%x, PERIOD: 0x%x\n", l, h);
147 l = hpet_readl(HPET_CFG);
148 h = hpet_readl(HPET_STATUS);
149 printk(KERN_INFO "hpet: CFG: 0x%x, STATUS: 0x%x\n", l, h);
150 l = hpet_readl(HPET_COUNTER);
151 h = hpet_readl(HPET_COUNTER+4);
152 printk(KERN_INFO "hpet: COUNTER_l: 0x%x, COUNTER_h: 0x%x\n", l, h);
153
154 for (i = 0; i < timers; i++) {
155 l = hpet_readl(HPET_Tn_CFG(i));
156 h = hpet_readl(HPET_Tn_CFG(i)+4);
157 printk(KERN_INFO "hpet: T%d: CFG_l: 0x%x, CFG_h: 0x%x\n",
158 i, l, h);
159 l = hpet_readl(HPET_Tn_CMP(i));
160 h = hpet_readl(HPET_Tn_CMP(i)+4);
161 printk(KERN_INFO "hpet: T%d: CMP_l: 0x%x, CMP_h: 0x%x\n",
162 i, l, h);
163 l = hpet_readl(HPET_Tn_ROUTE(i));
164 h = hpet_readl(HPET_Tn_ROUTE(i)+4);
165 printk(KERN_INFO "hpet: T%d ROUTE_l: 0x%x, ROUTE_h: 0x%x\n",
166 i, l, h);
167 }
168}
169
170#define hpet_print_config() \
171do { \
172 if (hpet_verbose) \
173 _hpet_print_config(__func__, __LINE__); \
174} while (0)
175
176/*
177 * When the hpet driver (/dev/hpet) is enabled, we need to reserve
178 * timer 0 and timer 1 in case of RTC emulation.
179 */
180#ifdef CONFIG_HPET
181
182static void hpet_reserve_msi_timers(struct hpet_data *hd);
183
184static void hpet_reserve_platform_timers(unsigned int id)
185{
186 struct hpet __iomem *hpet = hpet_virt_address;
187 struct hpet_timer __iomem *timer = &hpet->hpet_timers[2];
188 unsigned int nrtimers, i;
189 struct hpet_data hd;
190
191 nrtimers = ((id & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT) + 1;
192
193 memset(&hd, 0, sizeof(hd));
194 hd.hd_phys_address = hpet_address;
195 hd.hd_address = hpet;
196 hd.hd_nirqs = nrtimers;
197 hpet_reserve_timer(&hd, 0);
198
199#ifdef CONFIG_HPET_EMULATE_RTC
200 hpet_reserve_timer(&hd, 1);
201#endif
202
203 /*
204 * NOTE that hd_irq[] reflects IOAPIC input pins (LEGACY_8254
205 * is wrong for i8259!) not the output IRQ. Many BIOS writers
206 * don't bother configuring *any* comparator interrupts.
207 */
208 hd.hd_irq[0] = HPET_LEGACY_8254;
209 hd.hd_irq[1] = HPET_LEGACY_RTC;
210
211 for (i = 2; i < nrtimers; timer++, i++) {
212 hd.hd_irq[i] = (readl(&timer->hpet_config) &
213 Tn_INT_ROUTE_CNF_MASK) >> Tn_INT_ROUTE_CNF_SHIFT;
214 }
215
216 hpet_reserve_msi_timers(&hd);
217
218 hpet_alloc(&hd);
219
220}
221#else
222static void hpet_reserve_platform_timers(unsigned int id) { }
223#endif
224
225/*
226 * Common hpet info
227 */
228static unsigned long hpet_freq;
229
230static struct clock_event_device hpet_clockevent;
231
232static void hpet_stop_counter(void)
233{
234 u32 cfg = hpet_readl(HPET_CFG);
235 cfg &= ~HPET_CFG_ENABLE;
236 hpet_writel(cfg, HPET_CFG);
237}
238
239static void hpet_reset_counter(void)
240{
241 hpet_writel(0, HPET_COUNTER);
242 hpet_writel(0, HPET_COUNTER + 4);
243}
244
245static void hpet_start_counter(void)
246{
247 unsigned int cfg = hpet_readl(HPET_CFG);
248 cfg |= HPET_CFG_ENABLE;
249 hpet_writel(cfg, HPET_CFG);
250}
251
252static void hpet_restart_counter(void)
253{
254 hpet_stop_counter();
255 hpet_reset_counter();
256 hpet_start_counter();
257}
258
259static void hpet_resume_device(void)
260{
261 force_hpet_resume();
262}
263
264static void hpet_resume_counter(struct clocksource *cs)
265{
266 hpet_resume_device();
267 hpet_restart_counter();
268}
269
270static void hpet_enable_legacy_int(void)
271{
272 unsigned int cfg = hpet_readl(HPET_CFG);
273
274 cfg |= HPET_CFG_LEGACY;
275 hpet_writel(cfg, HPET_CFG);
276 hpet_legacy_int_enabled = true;
277}
278
279static void hpet_legacy_clockevent_register(void)
280{
281 /* Start HPET legacy interrupts */
282 hpet_enable_legacy_int();
283
284 /*
285 * Start hpet with the boot cpu mask and make it
286 * global after the IO_APIC has been initialized.
287 */
288 hpet_clockevent.cpumask = cpumask_of(smp_processor_id());
289 clockevents_config_and_register(&hpet_clockevent, hpet_freq,
290 HPET_MIN_PROG_DELTA, 0x7FFFFFFF);
291 global_clock_event = &hpet_clockevent;
292 printk(KERN_DEBUG "hpet clockevent registered\n");
293}
294
295static int hpet_set_periodic(struct clock_event_device *evt, int timer)
296{
297 unsigned int cfg, cmp, now;
298 uint64_t delta;
299
300 hpet_stop_counter();
301 delta = ((uint64_t)(NSEC_PER_SEC / HZ)) * evt->mult;
302 delta >>= evt->shift;
303 now = hpet_readl(HPET_COUNTER);
304 cmp = now + (unsigned int)delta;
305 cfg = hpet_readl(HPET_Tn_CFG(timer));
306 cfg |= HPET_TN_ENABLE | HPET_TN_PERIODIC | HPET_TN_SETVAL |
307 HPET_TN_32BIT;
308 hpet_writel(cfg, HPET_Tn_CFG(timer));
309 hpet_writel(cmp, HPET_Tn_CMP(timer));
310 udelay(1);
311 /*
312 * HPET on AMD 81xx needs a second write (with HPET_TN_SETVAL
313 * cleared) to T0_CMP to set the period. The HPET_TN_SETVAL
314 * bit is automatically cleared after the first write.
315 * (See AMD-8111 HyperTransport I/O Hub Data Sheet,
316 * Publication # 24674)
317 */
318 hpet_writel((unsigned int)delta, HPET_Tn_CMP(timer));
319 hpet_start_counter();
320 hpet_print_config();
321
322 return 0;
323}
324
325static int hpet_set_oneshot(struct clock_event_device *evt, int timer)
326{
327 unsigned int cfg;
328
329 cfg = hpet_readl(HPET_Tn_CFG(timer));
330 cfg &= ~HPET_TN_PERIODIC;
331 cfg |= HPET_TN_ENABLE | HPET_TN_32BIT;
332 hpet_writel(cfg, HPET_Tn_CFG(timer));
333
334 return 0;
335}
336
337static int hpet_shutdown(struct clock_event_device *evt, int timer)
338{
339 unsigned int cfg;
340
341 cfg = hpet_readl(HPET_Tn_CFG(timer));
342 cfg &= ~HPET_TN_ENABLE;
343 hpet_writel(cfg, HPET_Tn_CFG(timer));
344
345 return 0;
346}
347
348static int hpet_resume(struct clock_event_device *evt, int timer)
349{
350 if (!timer) {
351 hpet_enable_legacy_int();
352 } else {
353 struct hpet_dev *hdev = EVT_TO_HPET_DEV(evt);
354
355 irq_domain_deactivate_irq(irq_get_irq_data(hdev->irq));
356 irq_domain_activate_irq(irq_get_irq_data(hdev->irq));
357 disable_irq(hdev->irq);
358 irq_set_affinity(hdev->irq, cpumask_of(hdev->cpu));
359 enable_irq(hdev->irq);
360 }
361 hpet_print_config();
362
363 return 0;
364}
365
366static int hpet_next_event(unsigned long delta,
367 struct clock_event_device *evt, int timer)
368{
369 u32 cnt;
370 s32 res;
371
372 cnt = hpet_readl(HPET_COUNTER);
373 cnt += (u32) delta;
374 hpet_writel(cnt, HPET_Tn_CMP(timer));
375
376 /*
377 * HPETs are a complete disaster. The compare register is
378 * based on a equal comparison and neither provides a less
379 * than or equal functionality (which would require to take
380 * the wraparound into account) nor a simple count down event
381 * mode. Further the write to the comparator register is
382 * delayed internally up to two HPET clock cycles in certain
383 * chipsets (ATI, ICH9,10). Some newer AMD chipsets have even
384 * longer delays. We worked around that by reading back the
385 * compare register, but that required another workaround for
386 * ICH9,10 chips where the first readout after write can
387 * return the old stale value. We already had a minimum
388 * programming delta of 5us enforced, but a NMI or SMI hitting
389 * between the counter readout and the comparator write can
390 * move us behind that point easily. Now instead of reading
391 * the compare register back several times, we make the ETIME
392 * decision based on the following: Return ETIME if the
393 * counter value after the write is less than HPET_MIN_CYCLES
394 * away from the event or if the counter is already ahead of
395 * the event. The minimum programming delta for the generic
396 * clockevents code is set to 1.5 * HPET_MIN_CYCLES.
397 */
398 res = (s32)(cnt - hpet_readl(HPET_COUNTER));
399
400 return res < HPET_MIN_CYCLES ? -ETIME : 0;
401}
402
403static int hpet_legacy_shutdown(struct clock_event_device *evt)
404{
405 return hpet_shutdown(evt, 0);
406}
407
408static int hpet_legacy_set_oneshot(struct clock_event_device *evt)
409{
410 return hpet_set_oneshot(evt, 0);
411}
412
413static int hpet_legacy_set_periodic(struct clock_event_device *evt)
414{
415 return hpet_set_periodic(evt, 0);
416}
417
418static int hpet_legacy_resume(struct clock_event_device *evt)
419{
420 return hpet_resume(evt, 0);
421}
422
423static int hpet_legacy_next_event(unsigned long delta,
424 struct clock_event_device *evt)
425{
426 return hpet_next_event(delta, evt, 0);
427}
428
429/*
430 * The hpet clock event device
431 */
432static struct clock_event_device hpet_clockevent = {
433 .name = "hpet",
434 .features = CLOCK_EVT_FEAT_PERIODIC |
435 CLOCK_EVT_FEAT_ONESHOT,
436 .set_state_periodic = hpet_legacy_set_periodic,
437 .set_state_oneshot = hpet_legacy_set_oneshot,
438 .set_state_shutdown = hpet_legacy_shutdown,
439 .tick_resume = hpet_legacy_resume,
440 .set_next_event = hpet_legacy_next_event,
441 .irq = 0,
442 .rating = 50,
443};
444
445/*
446 * HPET MSI Support
447 */
448#ifdef CONFIG_PCI_MSI
449
450static DEFINE_PER_CPU(struct hpet_dev *, cpu_hpet_dev);
451static struct hpet_dev *hpet_devs;
452static struct irq_domain *hpet_domain;
453
454void hpet_msi_unmask(struct irq_data *data)
455{
456 struct hpet_dev *hdev = irq_data_get_irq_handler_data(data);
457 unsigned int cfg;
458
459 /* unmask it */
460 cfg = hpet_readl(HPET_Tn_CFG(hdev->num));
461 cfg |= HPET_TN_ENABLE | HPET_TN_FSB;
462 hpet_writel(cfg, HPET_Tn_CFG(hdev->num));
463}
464
465void hpet_msi_mask(struct irq_data *data)
466{
467 struct hpet_dev *hdev = irq_data_get_irq_handler_data(data);
468 unsigned int cfg;
469
470 /* mask it */
471 cfg = hpet_readl(HPET_Tn_CFG(hdev->num));
472 cfg &= ~(HPET_TN_ENABLE | HPET_TN_FSB);
473 hpet_writel(cfg, HPET_Tn_CFG(hdev->num));
474}
475
476void hpet_msi_write(struct hpet_dev *hdev, struct msi_msg *msg)
477{
478 hpet_writel(msg->data, HPET_Tn_ROUTE(hdev->num));
479 hpet_writel(msg->address_lo, HPET_Tn_ROUTE(hdev->num) + 4);
480}
481
482void hpet_msi_read(struct hpet_dev *hdev, struct msi_msg *msg)
483{
484 msg->data = hpet_readl(HPET_Tn_ROUTE(hdev->num));
485 msg->address_lo = hpet_readl(HPET_Tn_ROUTE(hdev->num) + 4);
486 msg->address_hi = 0;
487}
488
489static int hpet_msi_shutdown(struct clock_event_device *evt)
490{
491 struct hpet_dev *hdev = EVT_TO_HPET_DEV(evt);
492
493 return hpet_shutdown(evt, hdev->num);
494}
495
496static int hpet_msi_set_oneshot(struct clock_event_device *evt)
497{
498 struct hpet_dev *hdev = EVT_TO_HPET_DEV(evt);
499
500 return hpet_set_oneshot(evt, hdev->num);
501}
502
503static int hpet_msi_set_periodic(struct clock_event_device *evt)
504{
505 struct hpet_dev *hdev = EVT_TO_HPET_DEV(evt);
506
507 return hpet_set_periodic(evt, hdev->num);
508}
509
510static int hpet_msi_resume(struct clock_event_device *evt)
511{
512 struct hpet_dev *hdev = EVT_TO_HPET_DEV(evt);
513
514 return hpet_resume(evt, hdev->num);
515}
516
517static int hpet_msi_next_event(unsigned long delta,
518 struct clock_event_device *evt)
519{
520 struct hpet_dev *hdev = EVT_TO_HPET_DEV(evt);
521 return hpet_next_event(delta, evt, hdev->num);
522}
523
524static irqreturn_t hpet_interrupt_handler(int irq, void *data)
525{
526 struct hpet_dev *dev = (struct hpet_dev *)data;
527 struct clock_event_device *hevt = &dev->evt;
528
529 if (!hevt->event_handler) {
530 printk(KERN_INFO "Spurious HPET timer interrupt on HPET timer %d\n",
531 dev->num);
532 return IRQ_HANDLED;
533 }
534
535 hevt->event_handler(hevt);
536 return IRQ_HANDLED;
537}
538
539static int hpet_setup_irq(struct hpet_dev *dev)
540{
541
542 if (request_irq(dev->irq, hpet_interrupt_handler,
543 IRQF_TIMER | IRQF_NOBALANCING,
544 dev->name, dev))
545 return -1;
546
547 disable_irq(dev->irq);
548 irq_set_affinity(dev->irq, cpumask_of(dev->cpu));
549 enable_irq(dev->irq);
550
551 printk(KERN_DEBUG "hpet: %s irq %d for MSI\n",
552 dev->name, dev->irq);
553
554 return 0;
555}
556
557/* This should be called in specific @cpu */
558static void init_one_hpet_msi_clockevent(struct hpet_dev *hdev, int cpu)
559{
560 struct clock_event_device *evt = &hdev->evt;
561
562 WARN_ON(cpu != smp_processor_id());
563 if (!(hdev->flags & HPET_DEV_VALID))
564 return;
565
566 hdev->cpu = cpu;
567 per_cpu(cpu_hpet_dev, cpu) = hdev;
568 evt->name = hdev->name;
569 hpet_setup_irq(hdev);
570 evt->irq = hdev->irq;
571
572 evt->rating = 110;
573 evt->features = CLOCK_EVT_FEAT_ONESHOT;
574 if (hdev->flags & HPET_DEV_PERI_CAP) {
575 evt->features |= CLOCK_EVT_FEAT_PERIODIC;
576 evt->set_state_periodic = hpet_msi_set_periodic;
577 }
578
579 evt->set_state_shutdown = hpet_msi_shutdown;
580 evt->set_state_oneshot = hpet_msi_set_oneshot;
581 evt->tick_resume = hpet_msi_resume;
582 evt->set_next_event = hpet_msi_next_event;
583 evt->cpumask = cpumask_of(hdev->cpu);
584
585 clockevents_config_and_register(evt, hpet_freq, HPET_MIN_PROG_DELTA,
586 0x7FFFFFFF);
587}
588
589#ifdef CONFIG_HPET
590/* Reserve at least one timer for userspace (/dev/hpet) */
591#define RESERVE_TIMERS 1
592#else
593#define RESERVE_TIMERS 0
594#endif
595
596static void hpet_msi_capability_lookup(unsigned int start_timer)
597{
598 unsigned int id;
599 unsigned int num_timers;
600 unsigned int num_timers_used = 0;
601 int i, irq;
602
603 if (hpet_msi_disable)
604 return;
605
606 if (boot_cpu_has(X86_FEATURE_ARAT))
607 return;
608 id = hpet_readl(HPET_ID);
609
610 num_timers = ((id & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT);
611 num_timers++; /* Value read out starts from 0 */
612 hpet_print_config();
613
614 hpet_domain = hpet_create_irq_domain(hpet_blockid);
615 if (!hpet_domain)
616 return;
617
618 hpet_devs = kzalloc(sizeof(struct hpet_dev) * num_timers, GFP_KERNEL);
619 if (!hpet_devs)
620 return;
621
622 hpet_num_timers = num_timers;
623
624 for (i = start_timer; i < num_timers - RESERVE_TIMERS; i++) {
625 struct hpet_dev *hdev = &hpet_devs[num_timers_used];
626 unsigned int cfg = hpet_readl(HPET_Tn_CFG(i));
627
628 /* Only consider HPET timer with MSI support */
629 if (!(cfg & HPET_TN_FSB_CAP))
630 continue;
631
632 hdev->flags = 0;
633 if (cfg & HPET_TN_PERIODIC_CAP)
634 hdev->flags |= HPET_DEV_PERI_CAP;
635 sprintf(hdev->name, "hpet%d", i);
636 hdev->num = i;
637
638 irq = hpet_assign_irq(hpet_domain, hdev, hdev->num);
639 if (irq <= 0)
640 continue;
641
642 hdev->irq = irq;
643 hdev->flags |= HPET_DEV_FSB_CAP;
644 hdev->flags |= HPET_DEV_VALID;
645 num_timers_used++;
646 if (num_timers_used == num_possible_cpus())
647 break;
648 }
649
650 printk(KERN_INFO "HPET: %d timers in total, %d timers will be used for per-cpu timer\n",
651 num_timers, num_timers_used);
652}
653
654#ifdef CONFIG_HPET
655static void hpet_reserve_msi_timers(struct hpet_data *hd)
656{
657 int i;
658
659 if (!hpet_devs)
660 return;
661
662 for (i = 0; i < hpet_num_timers; i++) {
663 struct hpet_dev *hdev = &hpet_devs[i];
664
665 if (!(hdev->flags & HPET_DEV_VALID))
666 continue;
667
668 hd->hd_irq[hdev->num] = hdev->irq;
669 hpet_reserve_timer(hd, hdev->num);
670 }
671}
672#endif
673
674static struct hpet_dev *hpet_get_unused_timer(void)
675{
676 int i;
677
678 if (!hpet_devs)
679 return NULL;
680
681 for (i = 0; i < hpet_num_timers; i++) {
682 struct hpet_dev *hdev = &hpet_devs[i];
683
684 if (!(hdev->flags & HPET_DEV_VALID))
685 continue;
686 if (test_and_set_bit(HPET_DEV_USED_BIT,
687 (unsigned long *)&hdev->flags))
688 continue;
689 return hdev;
690 }
691 return NULL;
692}
693
694struct hpet_work_struct {
695 struct delayed_work work;
696 struct completion complete;
697};
698
699static void hpet_work(struct work_struct *w)
700{
701 struct hpet_dev *hdev;
702 int cpu = smp_processor_id();
703 struct hpet_work_struct *hpet_work;
704
705 hpet_work = container_of(w, struct hpet_work_struct, work.work);
706
707 hdev = hpet_get_unused_timer();
708 if (hdev)
709 init_one_hpet_msi_clockevent(hdev, cpu);
710
711 complete(&hpet_work->complete);
712}
713
714static int hpet_cpuhp_online(unsigned int cpu)
715{
716 struct hpet_work_struct work;
717
718 INIT_DELAYED_WORK_ONSTACK(&work.work, hpet_work);
719 init_completion(&work.complete);
720 /* FIXME: add schedule_work_on() */
721 schedule_delayed_work_on(cpu, &work.work, 0);
722 wait_for_completion(&work.complete);
723 destroy_delayed_work_on_stack(&work.work);
724 return 0;
725}
726
727static int hpet_cpuhp_dead(unsigned int cpu)
728{
729 struct hpet_dev *hdev = per_cpu(cpu_hpet_dev, cpu);
730
731 if (!hdev)
732 return 0;
733 free_irq(hdev->irq, hdev);
734 hdev->flags &= ~HPET_DEV_USED;
735 per_cpu(cpu_hpet_dev, cpu) = NULL;
736 return 0;
737}
738#else
739
740static void hpet_msi_capability_lookup(unsigned int start_timer)
741{
742 return;
743}
744
745#ifdef CONFIG_HPET
746static void hpet_reserve_msi_timers(struct hpet_data *hd)
747{
748 return;
749}
750#endif
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 delay 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 may 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. And we also need 64-bit atomic
777 * read.
778 *
779 * The lock and the hpet value are stored together and can be read in a
780 * single atomic 64-bit read. It is explicitly assumed that arch_spinlock_t
781 * is 32 bits in size.
782 */
783union hpet_lock {
784 struct {
785 arch_spinlock_t lock;
786 u32 value;
787 };
788 u64 lockval;
789};
790
791static union hpet_lock hpet __cacheline_aligned = {
792 { .lock = __ARCH_SPIN_LOCK_UNLOCKED, },
793};
794
795static u64 read_hpet(struct clocksource *cs)
796{
797 unsigned long flags;
798 union hpet_lock old, new;
799
800 BUILD_BUG_ON(sizeof(union hpet_lock) != 8);
801
802 /*
803 * Read HPET directly if in NMI.
804 */
805 if (in_nmi())
806 return (u64)hpet_readl(HPET_COUNTER);
807
808 /*
809 * Read the current state of the lock and HPET value atomically.
810 */
811 old.lockval = READ_ONCE(hpet.lockval);
812
813 if (arch_spin_is_locked(&old.lock))
814 goto contended;
815
816 local_irq_save(flags);
817 if (arch_spin_trylock(&hpet.lock)) {
818 new.value = hpet_readl(HPET_COUNTER);
819 /*
820 * Use WRITE_ONCE() to prevent store tearing.
821 */
822 WRITE_ONCE(hpet.value, new.value);
823 arch_spin_unlock(&hpet.lock);
824 local_irq_restore(flags);
825 return (u64)new.value;
826 }
827 local_irq_restore(flags);
828
829contended:
830 /*
831 * Contended case
832 * --------------
833 * Wait until the HPET value change or the lock is free to indicate
834 * its value is up-to-date.
835 *
836 * It is possible that old.value has already contained the latest
837 * HPET value while the lock holder was in the process of releasing
838 * the lock. Checking for lock state change will enable us to return
839 * the value immediately instead of waiting for the next HPET reader
840 * to come along.
841 */
842 do {
843 cpu_relax();
844 new.lockval = READ_ONCE(hpet.lockval);
845 } while ((new.value == old.value) && arch_spin_is_locked(&new.lock));
846
847 return (u64)new.value;
848}
849#else
850/*
851 * For UP or 32-bit.
852 */
853static u64 read_hpet(struct clocksource *cs)
854{
855 return (u64)hpet_readl(HPET_COUNTER);
856}
857#endif
858
859static struct clocksource clocksource_hpet = {
860 .name = "hpet",
861 .rating = 250,
862 .read = read_hpet,
863 .mask = HPET_MASK,
864 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
865 .resume = hpet_resume_counter,
866};
867
868static int hpet_clocksource_register(void)
869{
870 u64 start, now;
871 u64 t1;
872
873 /* Start the counter */
874 hpet_restart_counter();
875
876 /* Verify whether hpet counter works */
877 t1 = hpet_readl(HPET_COUNTER);
878 start = rdtsc();
879
880 /*
881 * We don't know the TSC frequency yet, but waiting for
882 * 200000 TSC cycles is safe:
883 * 4 GHz == 50us
884 * 1 GHz == 200us
885 */
886 do {
887 rep_nop();
888 now = rdtsc();
889 } while ((now - start) < 200000UL);
890
891 if (t1 == hpet_readl(HPET_COUNTER)) {
892 printk(KERN_WARNING
893 "HPET counter not counting. HPET disabled\n");
894 return -ENODEV;
895 }
896
897 clocksource_register_hz(&clocksource_hpet, (u32)hpet_freq);
898 return 0;
899}
900
901static u32 *hpet_boot_cfg;
902
903/**
904 * hpet_enable - Try to setup the HPET timer. Returns 1 on success.
905 */
906int __init hpet_enable(void)
907{
908 u32 hpet_period, cfg, id;
909 u64 freq;
910 unsigned int i, last;
911
912 if (!is_hpet_capable())
913 return 0;
914
915 hpet_set_mapping();
916
917 /*
918 * Read the period and check for a sane value:
919 */
920 hpet_period = hpet_readl(HPET_PERIOD);
921
922 /*
923 * AMD SB700 based systems with spread spectrum enabled use a
924 * SMM based HPET emulation to provide proper frequency
925 * setting. The SMM code is initialized with the first HPET
926 * register access and takes some time to complete. During
927 * this time the config register reads 0xffffffff. We check
928 * for max. 1000 loops whether the config register reads a non
929 * 0xffffffff value to make sure that HPET is up and running
930 * before we go further. A counting loop is safe, as the HPET
931 * access takes thousands of CPU cycles. On non SB700 based
932 * machines this check is only done once and has no side
933 * effects.
934 */
935 for (i = 0; hpet_readl(HPET_CFG) == 0xFFFFFFFF; i++) {
936 if (i == 1000) {
937 printk(KERN_WARNING
938 "HPET config register value = 0xFFFFFFFF. "
939 "Disabling HPET\n");
940 goto out_nohpet;
941 }
942 }
943
944 if (hpet_period < HPET_MIN_PERIOD || hpet_period > HPET_MAX_PERIOD)
945 goto out_nohpet;
946
947 /*
948 * The period is a femto seconds value. Convert it to a
949 * frequency.
950 */
951 freq = FSEC_PER_SEC;
952 do_div(freq, hpet_period);
953 hpet_freq = freq;
954
955 /*
956 * Read the HPET ID register to retrieve the IRQ routing
957 * information and the number of channels
958 */
959 id = hpet_readl(HPET_ID);
960 hpet_print_config();
961
962 last = (id & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT;
963
964#ifdef CONFIG_HPET_EMULATE_RTC
965 /*
966 * The legacy routing mode needs at least two channels, tick timer
967 * and the rtc emulation channel.
968 */
969 if (!last)
970 goto out_nohpet;
971#endif
972
973 cfg = hpet_readl(HPET_CFG);
974 hpet_boot_cfg = kmalloc((last + 2) * sizeof(*hpet_boot_cfg),
975 GFP_KERNEL);
976 if (hpet_boot_cfg)
977 *hpet_boot_cfg = cfg;
978 else
979 pr_warn("HPET initial state will not be saved\n");
980 cfg &= ~(HPET_CFG_ENABLE | HPET_CFG_LEGACY);
981 hpet_writel(cfg, HPET_CFG);
982 if (cfg)
983 pr_warn("HPET: Unrecognized bits %#x set in global cfg\n",
984 cfg);
985
986 for (i = 0; i <= last; ++i) {
987 cfg = hpet_readl(HPET_Tn_CFG(i));
988 if (hpet_boot_cfg)
989 hpet_boot_cfg[i + 1] = cfg;
990 cfg &= ~(HPET_TN_ENABLE | HPET_TN_LEVEL | HPET_TN_FSB);
991 hpet_writel(cfg, HPET_Tn_CFG(i));
992 cfg &= ~(HPET_TN_PERIODIC | HPET_TN_PERIODIC_CAP
993 | HPET_TN_64BIT_CAP | HPET_TN_32BIT | HPET_TN_ROUTE
994 | HPET_TN_FSB | HPET_TN_FSB_CAP);
995 if (cfg)
996 pr_warn("HPET: Unrecognized bits %#x set in cfg#%u\n",
997 cfg, i);
998 }
999 hpet_print_config();
1000
1001 if (hpet_clocksource_register())
1002 goto out_nohpet;
1003
1004 if (id & HPET_ID_LEGSUP) {
1005 hpet_legacy_clockevent_register();
1006 return 1;
1007 }
1008 return 0;
1009
1010out_nohpet:
1011 hpet_clear_mapping();
1012 hpet_address = 0;
1013 return 0;
1014}
1015
1016/*
1017 * Needs to be late, as the reserve_timer code calls kalloc !
1018 *
1019 * Not a problem on i386 as hpet_enable is called from late_time_init,
1020 * but on x86_64 it is necessary !
1021 */
1022static __init int hpet_late_init(void)
1023{
1024 int ret;
1025
1026 if (boot_hpet_disable)
1027 return -ENODEV;
1028
1029 if (!hpet_address) {
1030 if (!force_hpet_address)
1031 return -ENODEV;
1032
1033 hpet_address = force_hpet_address;
1034 hpet_enable();
1035 }
1036
1037 if (!hpet_virt_address)
1038 return -ENODEV;
1039
1040 if (hpet_readl(HPET_ID) & HPET_ID_LEGSUP)
1041 hpet_msi_capability_lookup(2);
1042 else
1043 hpet_msi_capability_lookup(0);
1044
1045 hpet_reserve_platform_timers(hpet_readl(HPET_ID));
1046 hpet_print_config();
1047
1048 if (hpet_msi_disable)
1049 return 0;
1050
1051 if (boot_cpu_has(X86_FEATURE_ARAT))
1052 return 0;
1053
1054 /* This notifier should be called after workqueue is ready */
1055 ret = cpuhp_setup_state(CPUHP_AP_X86_HPET_ONLINE, "x86/hpet:online",
1056 hpet_cpuhp_online, NULL);
1057 if (ret)
1058 return ret;
1059 ret = cpuhp_setup_state(CPUHP_X86_HPET_DEAD, "x86/hpet:dead", NULL,
1060 hpet_cpuhp_dead);
1061 if (ret)
1062 goto err_cpuhp;
1063 return 0;
1064
1065err_cpuhp:
1066 cpuhp_remove_state(CPUHP_AP_X86_HPET_ONLINE);
1067 return ret;
1068}
1069fs_initcall(hpet_late_init);
1070
1071void hpet_disable(void)
1072{
1073 if (is_hpet_capable() && hpet_virt_address) {
1074 unsigned int cfg = hpet_readl(HPET_CFG), id, last;
1075
1076 if (hpet_boot_cfg)
1077 cfg = *hpet_boot_cfg;
1078 else if (hpet_legacy_int_enabled) {
1079 cfg &= ~HPET_CFG_LEGACY;
1080 hpet_legacy_int_enabled = false;
1081 }
1082 cfg &= ~HPET_CFG_ENABLE;
1083 hpet_writel(cfg, HPET_CFG);
1084
1085 if (!hpet_boot_cfg)
1086 return;
1087
1088 id = hpet_readl(HPET_ID);
1089 last = ((id & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT);
1090
1091 for (id = 0; id <= last; ++id)
1092 hpet_writel(hpet_boot_cfg[id + 1], HPET_Tn_CFG(id));
1093
1094 if (*hpet_boot_cfg & HPET_CFG_ENABLE)
1095 hpet_writel(*hpet_boot_cfg, HPET_CFG);
1096 }
1097}
1098
1099#ifdef CONFIG_HPET_EMULATE_RTC
1100
1101/* HPET in LegacyReplacement Mode eats up RTC interrupt line. When, HPET
1102 * is enabled, we support RTC interrupt functionality in software.
1103 * RTC has 3 kinds of interrupts:
1104 * 1) Update Interrupt - generate an interrupt, every sec, when RTC clock
1105 * is updated
1106 * 2) Alarm Interrupt - generate an interrupt at a specific time of day
1107 * 3) Periodic Interrupt - generate periodic interrupt, with frequencies
1108 * 2Hz-8192Hz (2Hz-64Hz for non-root user) (all freqs in powers of 2)
1109 * (1) and (2) above are implemented using polling at a frequency of
1110 * 64 Hz. The exact frequency is a tradeoff between accuracy and interrupt
1111 * overhead. (DEFAULT_RTC_INT_FREQ)
1112 * For (3), we use interrupts at 64Hz or user specified periodic
1113 * frequency, whichever is higher.
1114 */
1115#include <linux/mc146818rtc.h>
1116#include <linux/rtc.h>
1117
1118#define DEFAULT_RTC_INT_FREQ 64
1119#define DEFAULT_RTC_SHIFT 6
1120#define RTC_NUM_INTS 1
1121
1122static unsigned long hpet_rtc_flags;
1123static int hpet_prev_update_sec;
1124static struct rtc_time hpet_alarm_time;
1125static unsigned long hpet_pie_count;
1126static u32 hpet_t1_cmp;
1127static u32 hpet_default_delta;
1128static u32 hpet_pie_delta;
1129static unsigned long hpet_pie_limit;
1130
1131static rtc_irq_handler irq_handler;
1132
1133/*
1134 * Check that the hpet counter c1 is ahead of the c2
1135 */
1136static inline int hpet_cnt_ahead(u32 c1, u32 c2)
1137{
1138 return (s32)(c2 - c1) < 0;
1139}
1140
1141/*
1142 * Registers a IRQ handler.
1143 */
1144int hpet_register_irq_handler(rtc_irq_handler handler)
1145{
1146 if (!is_hpet_enabled())
1147 return -ENODEV;
1148 if (irq_handler)
1149 return -EBUSY;
1150
1151 irq_handler = handler;
1152
1153 return 0;
1154}
1155EXPORT_SYMBOL_GPL(hpet_register_irq_handler);
1156
1157/*
1158 * Deregisters the IRQ handler registered with hpet_register_irq_handler()
1159 * and does cleanup.
1160 */
1161void hpet_unregister_irq_handler(rtc_irq_handler handler)
1162{
1163 if (!is_hpet_enabled())
1164 return;
1165
1166 irq_handler = NULL;
1167 hpet_rtc_flags = 0;
1168}
1169EXPORT_SYMBOL_GPL(hpet_unregister_irq_handler);
1170
1171/*
1172 * Timer 1 for RTC emulation. We use one shot mode, as periodic mode
1173 * is not supported by all HPET implementations for timer 1.
1174 *
1175 * hpet_rtc_timer_init() is called when the rtc is initialized.
1176 */
1177int hpet_rtc_timer_init(void)
1178{
1179 unsigned int cfg, cnt, delta;
1180 unsigned long flags;
1181
1182 if (!is_hpet_enabled())
1183 return 0;
1184
1185 if (!hpet_default_delta) {
1186 uint64_t clc;
1187
1188 clc = (uint64_t) hpet_clockevent.mult * NSEC_PER_SEC;
1189 clc >>= hpet_clockevent.shift + DEFAULT_RTC_SHIFT;
1190 hpet_default_delta = clc;
1191 }
1192
1193 if (!(hpet_rtc_flags & RTC_PIE) || hpet_pie_limit)
1194 delta = hpet_default_delta;
1195 else
1196 delta = hpet_pie_delta;
1197
1198 local_irq_save(flags);
1199
1200 cnt = delta + hpet_readl(HPET_COUNTER);
1201 hpet_writel(cnt, HPET_T1_CMP);
1202 hpet_t1_cmp = cnt;
1203
1204 cfg = hpet_readl(HPET_T1_CFG);
1205 cfg &= ~HPET_TN_PERIODIC;
1206 cfg |= HPET_TN_ENABLE | HPET_TN_32BIT;
1207 hpet_writel(cfg, HPET_T1_CFG);
1208
1209 local_irq_restore(flags);
1210
1211 return 1;
1212}
1213EXPORT_SYMBOL_GPL(hpet_rtc_timer_init);
1214
1215static void hpet_disable_rtc_channel(void)
1216{
1217 u32 cfg = hpet_readl(HPET_T1_CFG);
1218 cfg &= ~HPET_TN_ENABLE;
1219 hpet_writel(cfg, HPET_T1_CFG);
1220}
1221
1222/*
1223 * The functions below are called from rtc driver.
1224 * Return 0 if HPET is not being used.
1225 * Otherwise do the necessary changes and return 1.
1226 */
1227int hpet_mask_rtc_irq_bit(unsigned long bit_mask)
1228{
1229 if (!is_hpet_enabled())
1230 return 0;
1231
1232 hpet_rtc_flags &= ~bit_mask;
1233 if (unlikely(!hpet_rtc_flags))
1234 hpet_disable_rtc_channel();
1235
1236 return 1;
1237}
1238EXPORT_SYMBOL_GPL(hpet_mask_rtc_irq_bit);
1239
1240int hpet_set_rtc_irq_bit(unsigned long bit_mask)
1241{
1242 unsigned long oldbits = hpet_rtc_flags;
1243
1244 if (!is_hpet_enabled())
1245 return 0;
1246
1247 hpet_rtc_flags |= bit_mask;
1248
1249 if ((bit_mask & RTC_UIE) && !(oldbits & RTC_UIE))
1250 hpet_prev_update_sec = -1;
1251
1252 if (!oldbits)
1253 hpet_rtc_timer_init();
1254
1255 return 1;
1256}
1257EXPORT_SYMBOL_GPL(hpet_set_rtc_irq_bit);
1258
1259int hpet_set_alarm_time(unsigned char hrs, unsigned char min,
1260 unsigned char sec)
1261{
1262 if (!is_hpet_enabled())
1263 return 0;
1264
1265 hpet_alarm_time.tm_hour = hrs;
1266 hpet_alarm_time.tm_min = min;
1267 hpet_alarm_time.tm_sec = sec;
1268
1269 return 1;
1270}
1271EXPORT_SYMBOL_GPL(hpet_set_alarm_time);
1272
1273int hpet_set_periodic_freq(unsigned long freq)
1274{
1275 uint64_t clc;
1276
1277 if (!is_hpet_enabled())
1278 return 0;
1279
1280 if (freq <= DEFAULT_RTC_INT_FREQ)
1281 hpet_pie_limit = DEFAULT_RTC_INT_FREQ / freq;
1282 else {
1283 clc = (uint64_t) hpet_clockevent.mult * NSEC_PER_SEC;
1284 do_div(clc, freq);
1285 clc >>= hpet_clockevent.shift;
1286 hpet_pie_delta = clc;
1287 hpet_pie_limit = 0;
1288 }
1289 return 1;
1290}
1291EXPORT_SYMBOL_GPL(hpet_set_periodic_freq);
1292
1293int hpet_rtc_dropped_irq(void)
1294{
1295 return is_hpet_enabled();
1296}
1297EXPORT_SYMBOL_GPL(hpet_rtc_dropped_irq);
1298
1299static void hpet_rtc_timer_reinit(void)
1300{
1301 unsigned int delta;
1302 int lost_ints = -1;
1303
1304 if (unlikely(!hpet_rtc_flags))
1305 hpet_disable_rtc_channel();
1306
1307 if (!(hpet_rtc_flags & RTC_PIE) || hpet_pie_limit)
1308 delta = hpet_default_delta;
1309 else
1310 delta = hpet_pie_delta;
1311
1312 /*
1313 * Increment the comparator value until we are ahead of the
1314 * current count.
1315 */
1316 do {
1317 hpet_t1_cmp += delta;
1318 hpet_writel(hpet_t1_cmp, HPET_T1_CMP);
1319 lost_ints++;
1320 } while (!hpet_cnt_ahead(hpet_t1_cmp, hpet_readl(HPET_COUNTER)));
1321
1322 if (lost_ints) {
1323 if (hpet_rtc_flags & RTC_PIE)
1324 hpet_pie_count += lost_ints;
1325 if (printk_ratelimit())
1326 printk(KERN_WARNING "hpet1: lost %d rtc interrupts\n",
1327 lost_ints);
1328 }
1329}
1330
1331irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id)
1332{
1333 struct rtc_time curr_time;
1334 unsigned long rtc_int_flag = 0;
1335
1336 hpet_rtc_timer_reinit();
1337 memset(&curr_time, 0, sizeof(struct rtc_time));
1338
1339 if (hpet_rtc_flags & (RTC_UIE | RTC_AIE))
1340 mc146818_get_time(&curr_time);
1341
1342 if (hpet_rtc_flags & RTC_UIE &&
1343 curr_time.tm_sec != hpet_prev_update_sec) {
1344 if (hpet_prev_update_sec >= 0)
1345 rtc_int_flag = RTC_UF;
1346 hpet_prev_update_sec = curr_time.tm_sec;
1347 }
1348
1349 if (hpet_rtc_flags & RTC_PIE &&
1350 ++hpet_pie_count >= hpet_pie_limit) {
1351 rtc_int_flag |= RTC_PF;
1352 hpet_pie_count = 0;
1353 }
1354
1355 if (hpet_rtc_flags & RTC_AIE &&
1356 (curr_time.tm_sec == hpet_alarm_time.tm_sec) &&
1357 (curr_time.tm_min == hpet_alarm_time.tm_min) &&
1358 (curr_time.tm_hour == hpet_alarm_time.tm_hour))
1359 rtc_int_flag |= RTC_AF;
1360
1361 if (rtc_int_flag) {
1362 rtc_int_flag |= (RTC_IRQF | (RTC_NUM_INTS << 8));
1363 if (irq_handler)
1364 irq_handler(rtc_int_flag, dev_id);
1365 }
1366 return IRQ_HANDLED;
1367}
1368EXPORT_SYMBOL_GPL(hpet_rtc_interrupt);
1369#endif