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1 /*
2 * Timer device implementation for SGI SN platforms.
3 *
4 * This file is subject to the terms and conditions of the GNU General Public
5 * License. See the file "COPYING" in the main directory of this archive
6 * for more details.
7 *
8 * Copyright (c) 2001-2006 Silicon Graphics, Inc. All rights reserved.
9 *
10 * This driver exports an API that should be supportable by any HPET or IA-PC
11 * multimedia timer. The code below is currently specific to the SGI Altix
12 * SHub RTC, however.
13 *
14 * 11/01/01 - jbarnes - initial revision
15 * 9/10/04 - Christoph Lameter - remove interrupt support for kernel inclusion
16 * 10/1/04 - Christoph Lameter - provide posix clock CLOCK_SGI_CYCLE
17 * 10/13/04 - Christoph Lameter, Dimitri Sivanich - provide timer interrupt
18 * support via the posix timer interface
19 */
20
21 #include <linux/types.h>
22 #include <linux/kernel.h>
23 #include <linux/ioctl.h>
24 #include <linux/module.h>
25 #include <linux/init.h>
26 #include <linux/errno.h>
27 #include <linux/mm.h>
28 #include <linux/fs.h>
29 #include <linux/mmtimer.h>
30 #include <linux/miscdevice.h>
31 #include <linux/posix-timers.h>
32 #include <linux/interrupt.h>
33 #include <linux/time.h>
34 #include <linux/math64.h>
35 #include <linux/smp_lock.h>
36
37 #include <asm/uaccess.h>
38 #include <asm/sn/addrs.h>
39 #include <asm/sn/intr.h>
40 #include <asm/sn/shub_mmr.h>
41 #include <asm/sn/nodepda.h>
42 #include <asm/sn/shubio.h>
43
44 MODULE_AUTHOR("Jesse Barnes <jbarnes@sgi.com>");
45 MODULE_DESCRIPTION("SGI Altix RTC Timer");
46 MODULE_LICENSE("GPL");
47
48 /* name of the device, usually in /dev */
49 #define MMTIMER_NAME "mmtimer"
50 #define MMTIMER_DESC "SGI Altix RTC Timer"
51 #define MMTIMER_VERSION "2.1"
52
53 #define RTC_BITS 55 /* 55 bits for this implementation */
54
55 extern unsigned long sn_rtc_cycles_per_second;
56
57 #define RTC_COUNTER_ADDR ((long *)LOCAL_MMR_ADDR(SH_RTC))
58
59 #define rtc_time() (*RTC_COUNTER_ADDR)
60
61 static long mmtimer_ioctl(struct file *file, unsigned int cmd,
62 unsigned long arg);
63 static int mmtimer_mmap(struct file *file, struct vm_area_struct *vma);
64
65 /*
66 * Period in femtoseconds (10^-15 s)
67 */
68 static unsigned long mmtimer_femtoperiod = 0;
69
70 static const struct file_operations mmtimer_fops = {
71 .owner = THIS_MODULE,
72 .mmap = mmtimer_mmap,
73 .unlocked_ioctl = mmtimer_ioctl,
74 };
75
76 /*
77 * We only have comparison registers RTC1-4 currently available per
78 * node. RTC0 is used by SAL.
79 */
80 /* Check for an RTC interrupt pending */
81 static int mmtimer_int_pending(int comparator)
82 {
83 if (HUB_L((unsigned long *)LOCAL_MMR_ADDR(SH_EVENT_OCCURRED)) &
84 SH_EVENT_OCCURRED_RTC1_INT_MASK << comparator)
85 return 1;
86 else
87 return 0;
88 }
89
90 /* Clear the RTC interrupt pending bit */
91 static void mmtimer_clr_int_pending(int comparator)
92 {
93 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_EVENT_OCCURRED_ALIAS),
94 SH_EVENT_OCCURRED_RTC1_INT_MASK << comparator);
95 }
96
97 /* Setup timer on comparator RTC1 */
98 static void mmtimer_setup_int_0(int cpu, u64 expires)
99 {
100 u64 val;
101
102 /* Disable interrupt */
103 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC1_INT_ENABLE), 0UL);
104
105 /* Initialize comparator value */
106 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPB), -1L);
107
108 /* Clear pending bit */
109 mmtimer_clr_int_pending(0);
110
111 val = ((u64)SGI_MMTIMER_VECTOR << SH_RTC1_INT_CONFIG_IDX_SHFT) |
112 ((u64)cpu_physical_id(cpu) <<
113 SH_RTC1_INT_CONFIG_PID_SHFT);
114
115 /* Set configuration */
116 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC1_INT_CONFIG), val);
117
118 /* Enable RTC interrupts */
119 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC1_INT_ENABLE), 1UL);
120
121 /* Initialize comparator value */
122 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPB), expires);
123
124
125 }
126
127 /* Setup timer on comparator RTC2 */
128 static void mmtimer_setup_int_1(int cpu, u64 expires)
129 {
130 u64 val;
131
132 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC2_INT_ENABLE), 0UL);
133
134 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPC), -1L);
135
136 mmtimer_clr_int_pending(1);
137
138 val = ((u64)SGI_MMTIMER_VECTOR << SH_RTC2_INT_CONFIG_IDX_SHFT) |
139 ((u64)cpu_physical_id(cpu) <<
140 SH_RTC2_INT_CONFIG_PID_SHFT);
141
142 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC2_INT_CONFIG), val);
143
144 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC2_INT_ENABLE), 1UL);
145
146 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPC), expires);
147 }
148
149 /* Setup timer on comparator RTC3 */
150 static void mmtimer_setup_int_2(int cpu, u64 expires)
151 {
152 u64 val;
153
154 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC3_INT_ENABLE), 0UL);
155
156 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPD), -1L);
157
158 mmtimer_clr_int_pending(2);
159
160 val = ((u64)SGI_MMTIMER_VECTOR << SH_RTC3_INT_CONFIG_IDX_SHFT) |
161 ((u64)cpu_physical_id(cpu) <<
162 SH_RTC3_INT_CONFIG_PID_SHFT);
163
164 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC3_INT_CONFIG), val);
165
166 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC3_INT_ENABLE), 1UL);
167
168 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPD), expires);
169 }
170
171 /*
172 * This function must be called with interrupts disabled and preemption off
173 * in order to insure that the setup succeeds in a deterministic time frame.
174 * It will check if the interrupt setup succeeded.
175 */
176 static int mmtimer_setup(int cpu, int comparator, unsigned long expires)
177 {
178
179 switch (comparator) {
180 case 0:
181 mmtimer_setup_int_0(cpu, expires);
182 break;
183 case 1:
184 mmtimer_setup_int_1(cpu, expires);
185 break;
186 case 2:
187 mmtimer_setup_int_2(cpu, expires);
188 break;
189 }
190 /* We might've missed our expiration time */
191 if (rtc_time() <= expires)
192 return 1;
193
194 /*
195 * If an interrupt is already pending then its okay
196 * if not then we failed
197 */
198 return mmtimer_int_pending(comparator);
199 }
200
201 static int mmtimer_disable_int(long nasid, int comparator)
202 {
203 switch (comparator) {
204 case 0:
205 nasid == -1 ? HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC1_INT_ENABLE),
206 0UL) : REMOTE_HUB_S(nasid, SH_RTC1_INT_ENABLE, 0UL);
207 break;
208 case 1:
209 nasid == -1 ? HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC2_INT_ENABLE),
210 0UL) : REMOTE_HUB_S(nasid, SH_RTC2_INT_ENABLE, 0UL);
211 break;
212 case 2:
213 nasid == -1 ? HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC3_INT_ENABLE),
214 0UL) : REMOTE_HUB_S(nasid, SH_RTC3_INT_ENABLE, 0UL);
215 break;
216 default:
217 return -EFAULT;
218 }
219 return 0;
220 }
221
222 #define COMPARATOR 1 /* The comparator to use */
223
224 #define TIMER_OFF 0xbadcabLL /* Timer is not setup */
225 #define TIMER_SET 0 /* Comparator is set for this timer */
226
227 /* There is one of these for each timer */
228 struct mmtimer {
229 struct rb_node list;
230 struct k_itimer *timer;
231 int cpu;
232 };
233
234 struct mmtimer_node {
235 spinlock_t lock ____cacheline_aligned;
236 struct rb_root timer_head;
237 struct rb_node *next;
238 struct tasklet_struct tasklet;
239 };
240 static struct mmtimer_node *timers;
241
242
243 /*
244 * Add a new mmtimer struct to the node's mmtimer list.
245 * This function assumes the struct mmtimer_node is locked.
246 */
247 static void mmtimer_add_list(struct mmtimer *n)
248 {
249 int nodeid = n->timer->it.mmtimer.node;
250 unsigned long expires = n->timer->it.mmtimer.expires;
251 struct rb_node **link = &timers[nodeid].timer_head.rb_node;
252 struct rb_node *parent = NULL;
253 struct mmtimer *x;
254
255 /*
256 * Find the right place in the rbtree:
257 */
258 while (*link) {
259 parent = *link;
260 x = rb_entry(parent, struct mmtimer, list);
261
262 if (expires < x->timer->it.mmtimer.expires)
263 link = &(*link)->rb_left;
264 else
265 link = &(*link)->rb_right;
266 }
267
268 /*
269 * Insert the timer to the rbtree and check whether it
270 * replaces the first pending timer
271 */
272 rb_link_node(&n->list, parent, link);
273 rb_insert_color(&n->list, &timers[nodeid].timer_head);
274
275 if (!timers[nodeid].next || expires < rb_entry(timers[nodeid].next,
276 struct mmtimer, list)->timer->it.mmtimer.expires)
277 timers[nodeid].next = &n->list;
278 }
279
280 /*
281 * Set the comparator for the next timer.
282 * This function assumes the struct mmtimer_node is locked.
283 */
284 static void mmtimer_set_next_timer(int nodeid)
285 {
286 struct mmtimer_node *n = &timers[nodeid];
287 struct mmtimer *x;
288 struct k_itimer *t;
289 int o;
290
291 restart:
292 if (n->next == NULL)
293 return;
294
295 x = rb_entry(n->next, struct mmtimer, list);
296 t = x->timer;
297 if (!t->it.mmtimer.incr) {
298 /* Not an interval timer */
299 if (!mmtimer_setup(x->cpu, COMPARATOR,
300 t->it.mmtimer.expires)) {
301 /* Late setup, fire now */
302 tasklet_schedule(&n->tasklet);
303 }
304 return;
305 }
306
307 /* Interval timer */
308 o = 0;
309 while (!mmtimer_setup(x->cpu, COMPARATOR, t->it.mmtimer.expires)) {
310 unsigned long e, e1;
311 struct rb_node *next;
312 t->it.mmtimer.expires += t->it.mmtimer.incr << o;
313 t->it_overrun += 1 << o;
314 o++;
315 if (o > 20) {
316 printk(KERN_ALERT "mmtimer: cannot reschedule timer\n");
317 t->it.mmtimer.clock = TIMER_OFF;
318 n->next = rb_next(&x->list);
319 rb_erase(&x->list, &n->timer_head);
320 kfree(x);
321 goto restart;
322 }
323
324 e = t->it.mmtimer.expires;
325 next = rb_next(&x->list);
326
327 if (next == NULL)
328 continue;
329
330 e1 = rb_entry(next, struct mmtimer, list)->
331 timer->it.mmtimer.expires;
332 if (e > e1) {
333 n->next = next;
334 rb_erase(&x->list, &n->timer_head);
335 mmtimer_add_list(x);
336 goto restart;
337 }
338 }
339 }
340
341 /**
342 * mmtimer_ioctl - ioctl interface for /dev/mmtimer
343 * @file: file structure for the device
344 * @cmd: command to execute
345 * @arg: optional argument to command
346 *
347 * Executes the command specified by @cmd. Returns 0 for success, < 0 for
348 * failure.
349 *
350 * Valid commands:
351 *
352 * %MMTIMER_GETOFFSET - Should return the offset (relative to the start
353 * of the page where the registers are mapped) for the counter in question.
354 *
355 * %MMTIMER_GETRES - Returns the resolution of the clock in femto (10^-15)
356 * seconds
357 *
358 * %MMTIMER_GETFREQ - Copies the frequency of the clock in Hz to the address
359 * specified by @arg
360 *
361 * %MMTIMER_GETBITS - Returns the number of bits in the clock's counter
362 *
363 * %MMTIMER_MMAPAVAIL - Returns 1 if the registers can be mmap'd into userspace
364 *
365 * %MMTIMER_GETCOUNTER - Gets the current value in the counter and places it
366 * in the address specified by @arg.
367 */
368 static long mmtimer_ioctl(struct file *file, unsigned int cmd,
369 unsigned long arg)
370 {
371 int ret = 0;
372
373 lock_kernel();
374
375 switch (cmd) {
376 case MMTIMER_GETOFFSET: /* offset of the counter */
377 /*
378 * SN RTC registers are on their own 64k page
379 */
380 if(PAGE_SIZE <= (1 << 16))
381 ret = (((long)RTC_COUNTER_ADDR) & (PAGE_SIZE-1)) / 8;
382 else
383 ret = -ENOSYS;
384 break;
385
386 case MMTIMER_GETRES: /* resolution of the clock in 10^-15 s */
387 if(copy_to_user((unsigned long __user *)arg,
388 &mmtimer_femtoperiod, sizeof(unsigned long)))
389 ret = -EFAULT;
390 break;
391
392 case MMTIMER_GETFREQ: /* frequency in Hz */
393 if(copy_to_user((unsigned long __user *)arg,
394 &sn_rtc_cycles_per_second,
395 sizeof(unsigned long)))
396 ret = -EFAULT;
397 break;
398
399 case MMTIMER_GETBITS: /* number of bits in the clock */
400 ret = RTC_BITS;
401 break;
402
403 case MMTIMER_MMAPAVAIL: /* can we mmap the clock into userspace? */
404 ret = (PAGE_SIZE <= (1 << 16)) ? 1 : 0;
405 break;
406
407 case MMTIMER_GETCOUNTER:
408 if(copy_to_user((unsigned long __user *)arg,
409 RTC_COUNTER_ADDR, sizeof(unsigned long)))
410 ret = -EFAULT;
411 break;
412 default:
413 ret = -ENOTTY;
414 break;
415 }
416 unlock_kernel();
417 return ret;
418 }
419
420 /**
421 * mmtimer_mmap - maps the clock's registers into userspace
422 * @file: file structure for the device
423 * @vma: VMA to map the registers into
424 *
425 * Calls remap_pfn_range() to map the clock's registers into
426 * the calling process' address space.
427 */
428 static int mmtimer_mmap(struct file *file, struct vm_area_struct *vma)
429 {
430 unsigned long mmtimer_addr;
431
432 if (vma->vm_end - vma->vm_start != PAGE_SIZE)
433 return -EINVAL;
434
435 if (vma->vm_flags & VM_WRITE)
436 return -EPERM;
437
438 if (PAGE_SIZE > (1 << 16))
439 return -ENOSYS;
440
441 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
442
443 mmtimer_addr = __pa(RTC_COUNTER_ADDR);
444 mmtimer_addr &= ~(PAGE_SIZE - 1);
445 mmtimer_addr &= 0xfffffffffffffffUL;
446
447 if (remap_pfn_range(vma, vma->vm_start, mmtimer_addr >> PAGE_SHIFT,
448 PAGE_SIZE, vma->vm_page_prot)) {
449 printk(KERN_ERR "remap_pfn_range failed in mmtimer.c\n");
450 return -EAGAIN;
451 }
452
453 return 0;
454 }
455
456 static struct miscdevice mmtimer_miscdev = {
457 SGI_MMTIMER,
458 MMTIMER_NAME,
459 &mmtimer_fops
460 };
461
462 static struct timespec sgi_clock_offset;
463 static int sgi_clock_period;
464
465 /*
466 * Posix Timer Interface
467 */
468
469 static struct timespec sgi_clock_offset;
470 static int sgi_clock_period;
471
472 static int sgi_clock_get(clockid_t clockid, struct timespec *tp)
473 {
474 u64 nsec;
475
476 nsec = rtc_time() * sgi_clock_period
477 + sgi_clock_offset.tv_nsec;
478 *tp = ns_to_timespec(nsec);
479 tp->tv_sec += sgi_clock_offset.tv_sec;
480 return 0;
481 };
482
483 static int sgi_clock_set(clockid_t clockid, struct timespec *tp)
484 {
485
486 u64 nsec;
487 u32 rem;
488
489 nsec = rtc_time() * sgi_clock_period;
490
491 sgi_clock_offset.tv_sec = tp->tv_sec - div_u64_rem(nsec, NSEC_PER_SEC, &rem);
492
493 if (rem <= tp->tv_nsec)
494 sgi_clock_offset.tv_nsec = tp->tv_sec - rem;
495 else {
496 sgi_clock_offset.tv_nsec = tp->tv_sec + NSEC_PER_SEC - rem;
497 sgi_clock_offset.tv_sec--;
498 }
499 return 0;
500 }
501
502 /**
503 * mmtimer_interrupt - timer interrupt handler
504 * @irq: irq received
505 * @dev_id: device the irq came from
506 *
507 * Called when one of the comarators matches the counter, This
508 * routine will send signals to processes that have requested
509 * them.
510 *
511 * This interrupt is run in an interrupt context
512 * by the SHUB. It is therefore safe to locally access SHub
513 * registers.
514 */
515 static irqreturn_t
516 mmtimer_interrupt(int irq, void *dev_id)
517 {
518 unsigned long expires = 0;
519 int result = IRQ_NONE;
520 unsigned indx = cpu_to_node(smp_processor_id());
521 struct mmtimer *base;
522
523 spin_lock(&timers[indx].lock);
524 base = rb_entry(timers[indx].next, struct mmtimer, list);
525 if (base == NULL) {
526 spin_unlock(&timers[indx].lock);
527 return result;
528 }
529
530 if (base->cpu == smp_processor_id()) {
531 if (base->timer)
532 expires = base->timer->it.mmtimer.expires;
533 /* expires test won't work with shared irqs */
534 if ((mmtimer_int_pending(COMPARATOR) > 0) ||
535 (expires && (expires <= rtc_time()))) {
536 mmtimer_clr_int_pending(COMPARATOR);
537 tasklet_schedule(&timers[indx].tasklet);
538 result = IRQ_HANDLED;
539 }
540 }
541 spin_unlock(&timers[indx].lock);
542 return result;
543 }
544
545 static void mmtimer_tasklet(unsigned long data)
546 {
547 int nodeid = data;
548 struct mmtimer_node *mn = &timers[nodeid];
549 struct mmtimer *x = rb_entry(mn->next, struct mmtimer, list);
550 struct k_itimer *t;
551 unsigned long flags;
552
553 /* Send signal and deal with periodic signals */
554 spin_lock_irqsave(&mn->lock, flags);
555 if (!mn->next)
556 goto out;
557
558 x = rb_entry(mn->next, struct mmtimer, list);
559 t = x->timer;
560
561 if (t->it.mmtimer.clock == TIMER_OFF)
562 goto out;
563
564 t->it_overrun = 0;
565
566 mn->next = rb_next(&x->list);
567 rb_erase(&x->list, &mn->timer_head);
568
569 if (posix_timer_event(t, 0) != 0)
570 t->it_overrun++;
571
572 if(t->it.mmtimer.incr) {
573 t->it.mmtimer.expires += t->it.mmtimer.incr;
574 mmtimer_add_list(x);
575 } else {
576 /* Ensure we don't false trigger in mmtimer_interrupt */
577 t->it.mmtimer.clock = TIMER_OFF;
578 t->it.mmtimer.expires = 0;
579 kfree(x);
580 }
581 /* Set comparator for next timer, if there is one */
582 mmtimer_set_next_timer(nodeid);
583
584 t->it_overrun_last = t->it_overrun;
585 out:
586 spin_unlock_irqrestore(&mn->lock, flags);
587 }
588
589 static int sgi_timer_create(struct k_itimer *timer)
590 {
591 /* Insure that a newly created timer is off */
592 timer->it.mmtimer.clock = TIMER_OFF;
593 return 0;
594 }
595
596 /* This does not really delete a timer. It just insures
597 * that the timer is not active
598 *
599 * Assumption: it_lock is already held with irq's disabled
600 */
601 static int sgi_timer_del(struct k_itimer *timr)
602 {
603 cnodeid_t nodeid = timr->it.mmtimer.node;
604 unsigned long irqflags;
605
606 spin_lock_irqsave(&timers[nodeid].lock, irqflags);
607 if (timr->it.mmtimer.clock != TIMER_OFF) {
608 unsigned long expires = timr->it.mmtimer.expires;
609 struct rb_node *n = timers[nodeid].timer_head.rb_node;
610 struct mmtimer *uninitialized_var(t);
611 int r = 0;
612
613 timr->it.mmtimer.clock = TIMER_OFF;
614 timr->it.mmtimer.expires = 0;
615
616 while (n) {
617 t = rb_entry(n, struct mmtimer, list);
618 if (t->timer == timr)
619 break;
620
621 if (expires < t->timer->it.mmtimer.expires)
622 n = n->rb_left;
623 else
624 n = n->rb_right;
625 }
626
627 if (!n) {
628 spin_unlock_irqrestore(&timers[nodeid].lock, irqflags);
629 return 0;
630 }
631
632 if (timers[nodeid].next == n) {
633 timers[nodeid].next = rb_next(n);
634 r = 1;
635 }
636
637 rb_erase(n, &timers[nodeid].timer_head);
638 kfree(t);
639
640 if (r) {
641 mmtimer_disable_int(cnodeid_to_nasid(nodeid),
642 COMPARATOR);
643 mmtimer_set_next_timer(nodeid);
644 }
645 }
646 spin_unlock_irqrestore(&timers[nodeid].lock, irqflags);
647 return 0;
648 }
649
650 /* Assumption: it_lock is already held with irq's disabled */
651 static void sgi_timer_get(struct k_itimer *timr, struct itimerspec *cur_setting)
652 {
653
654 if (timr->it.mmtimer.clock == TIMER_OFF) {
655 cur_setting->it_interval.tv_nsec = 0;
656 cur_setting->it_interval.tv_sec = 0;
657 cur_setting->it_value.tv_nsec = 0;
658 cur_setting->it_value.tv_sec =0;
659 return;
660 }
661
662 cur_setting->it_interval = ns_to_timespec(timr->it.mmtimer.incr * sgi_clock_period);
663 cur_setting->it_value = ns_to_timespec((timr->it.mmtimer.expires - rtc_time()) * sgi_clock_period);
664 }
665
666
667 static int sgi_timer_set(struct k_itimer *timr, int flags,
668 struct itimerspec * new_setting,
669 struct itimerspec * old_setting)
670 {
671 unsigned long when, period, irqflags;
672 int err = 0;
673 cnodeid_t nodeid;
674 struct mmtimer *base;
675 struct rb_node *n;
676
677 if (old_setting)
678 sgi_timer_get(timr, old_setting);
679
680 sgi_timer_del(timr);
681 when = timespec_to_ns(&new_setting->it_value);
682 period = timespec_to_ns(&new_setting->it_interval);
683
684 if (when == 0)
685 /* Clear timer */
686 return 0;
687
688 base = kmalloc(sizeof(struct mmtimer), GFP_KERNEL);
689 if (base == NULL)
690 return -ENOMEM;
691
692 if (flags & TIMER_ABSTIME) {
693 struct timespec n;
694 unsigned long now;
695
696 getnstimeofday(&n);
697 now = timespec_to_ns(&n);
698 if (when > now)
699 when -= now;
700 else
701 /* Fire the timer immediately */
702 when = 0;
703 }
704
705 /*
706 * Convert to sgi clock period. Need to keep rtc_time() as near as possible
707 * to getnstimeofday() in order to be as faithful as possible to the time
708 * specified.
709 */
710 when = (when + sgi_clock_period - 1) / sgi_clock_period + rtc_time();
711 period = (period + sgi_clock_period - 1) / sgi_clock_period;
712
713 /*
714 * We are allocating a local SHub comparator. If we would be moved to another
715 * cpu then another SHub may be local to us. Prohibit that by switching off
716 * preemption.
717 */
718 preempt_disable();
719
720 nodeid = cpu_to_node(smp_processor_id());
721
722 /* Lock the node timer structure */
723 spin_lock_irqsave(&timers[nodeid].lock, irqflags);
724
725 base->timer = timr;
726 base->cpu = smp_processor_id();
727
728 timr->it.mmtimer.clock = TIMER_SET;
729 timr->it.mmtimer.node = nodeid;
730 timr->it.mmtimer.incr = period;
731 timr->it.mmtimer.expires = when;
732
733 n = timers[nodeid].next;
734
735 /* Add the new struct mmtimer to node's timer list */
736 mmtimer_add_list(base);
737
738 if (timers[nodeid].next == n) {
739 /* No need to reprogram comparator for now */
740 spin_unlock_irqrestore(&timers[nodeid].lock, irqflags);
741 preempt_enable();
742 return err;
743 }
744
745 /* We need to reprogram the comparator */
746 if (n)
747 mmtimer_disable_int(cnodeid_to_nasid(nodeid), COMPARATOR);
748
749 mmtimer_set_next_timer(nodeid);
750
751 /* Unlock the node timer structure */
752 spin_unlock_irqrestore(&timers[nodeid].lock, irqflags);
753
754 preempt_enable();
755
756 return err;
757 }
758
759 static struct k_clock sgi_clock = {
760 .res = 0,
761 .clock_set = sgi_clock_set,
762 .clock_get = sgi_clock_get,
763 .timer_create = sgi_timer_create,
764 .nsleep = do_posix_clock_nonanosleep,
765 .timer_set = sgi_timer_set,
766 .timer_del = sgi_timer_del,
767 .timer_get = sgi_timer_get
768 };
769
770 /**
771 * mmtimer_init - device initialization routine
772 *
773 * Does initial setup for the mmtimer device.
774 */
775 static int __init mmtimer_init(void)
776 {
777 cnodeid_t node, maxn = -1;
778
779 if (!ia64_platform_is("sn2"))
780 return 0;
781
782 /*
783 * Sanity check the cycles/sec variable
784 */
785 if (sn_rtc_cycles_per_second < 100000) {
786 printk(KERN_ERR "%s: unable to determine clock frequency\n",
787 MMTIMER_NAME);
788 goto out1;
789 }
790
791 mmtimer_femtoperiod = ((unsigned long)1E15 + sn_rtc_cycles_per_second /
792 2) / sn_rtc_cycles_per_second;
793
794 if (request_irq(SGI_MMTIMER_VECTOR, mmtimer_interrupt, IRQF_PERCPU, MMTIMER_NAME, NULL)) {
795 printk(KERN_WARNING "%s: unable to allocate interrupt.",
796 MMTIMER_NAME);
797 goto out1;
798 }
799
800 if (misc_register(&mmtimer_miscdev)) {
801 printk(KERN_ERR "%s: failed to register device\n",
802 MMTIMER_NAME);
803 goto out2;
804 }
805
806 /* Get max numbered node, calculate slots needed */
807 for_each_online_node(node) {
808 maxn = node;
809 }
810 maxn++;
811
812 /* Allocate list of node ptrs to mmtimer_t's */
813 timers = kzalloc(sizeof(struct mmtimer_node)*maxn, GFP_KERNEL);
814 if (timers == NULL) {
815 printk(KERN_ERR "%s: failed to allocate memory for device\n",
816 MMTIMER_NAME);
817 goto out3;
818 }
819
820 /* Initialize struct mmtimer's for each online node */
821 for_each_online_node(node) {
822 spin_lock_init(&timers[node].lock);
823 tasklet_init(&timers[node].tasklet, mmtimer_tasklet,
824 (unsigned long) node);
825 }
826
827 sgi_clock_period = sgi_clock.res = NSEC_PER_SEC / sn_rtc_cycles_per_second;
828 register_posix_clock(CLOCK_SGI_CYCLE, &sgi_clock);
829
830 printk(KERN_INFO "%s: v%s, %ld MHz\n", MMTIMER_DESC, MMTIMER_VERSION,
831 sn_rtc_cycles_per_second/(unsigned long)1E6);
832
833 return 0;
834
835 out3:
836 kfree(timers);
837 misc_deregister(&mmtimer_miscdev);
838 out2:
839 free_irq(SGI_MMTIMER_VECTOR, NULL);
840 out1:
841 return -1;
842 }
843
844 module_init(mmtimer_init);