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/mutex.h>
36 #include <linux/slab.h>
37
38 #include <asm/uaccess.h>
39 #include <asm/sn/addrs.h>
40 #include <asm/sn/intr.h>
41 #include <asm/sn/shub_mmr.h>
42 #include <asm/sn/nodepda.h>
43 #include <asm/sn/shubio.h>
44
45 MODULE_AUTHOR("Jesse Barnes <jbarnes@sgi.com>");
46 MODULE_DESCRIPTION("SGI Altix RTC Timer");
47 MODULE_LICENSE("GPL");
48
49 /* name of the device, usually in /dev */
50 #define MMTIMER_NAME "mmtimer"
51 #define MMTIMER_DESC "SGI Altix RTC Timer"
52 #define MMTIMER_VERSION "2.1"
53
54 #define RTC_BITS 55 /* 55 bits for this implementation */
55
56 static struct k_clock sgi_clock;
57
58 extern unsigned long sn_rtc_cycles_per_second;
59
60 #define RTC_COUNTER_ADDR ((long *)LOCAL_MMR_ADDR(SH_RTC))
61
62 #define rtc_time() (*RTC_COUNTER_ADDR)
63
64 static DEFINE_MUTEX(mmtimer_mutex);
65 static long mmtimer_ioctl(struct file *file, unsigned int cmd,
66 unsigned long arg);
67 static int mmtimer_mmap(struct file *file, struct vm_area_struct *vma);
68
69 /*
70 * Period in femtoseconds (10^-15 s)
71 */
72 static unsigned long mmtimer_femtoperiod = 0;
73
74 static const struct file_operations mmtimer_fops = {
75 .owner = THIS_MODULE,
76 .mmap = mmtimer_mmap,
77 .unlocked_ioctl = mmtimer_ioctl,
78 .llseek = noop_llseek,
79 };
80
81 /*
82 * We only have comparison registers RTC1-4 currently available per
83 * node. RTC0 is used by SAL.
84 */
85 /* Check for an RTC interrupt pending */
mmtimer_int_pending(int comparator)86 static int mmtimer_int_pending(int comparator)
87 {
88 if (HUB_L((unsigned long *)LOCAL_MMR_ADDR(SH_EVENT_OCCURRED)) &
89 SH_EVENT_OCCURRED_RTC1_INT_MASK << comparator)
90 return 1;
91 else
92 return 0;
93 }
94
95 /* Clear the RTC interrupt pending bit */
mmtimer_clr_int_pending(int comparator)96 static void mmtimer_clr_int_pending(int comparator)
97 {
98 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_EVENT_OCCURRED_ALIAS),
99 SH_EVENT_OCCURRED_RTC1_INT_MASK << comparator);
100 }
101
102 /* Setup timer on comparator RTC1 */
mmtimer_setup_int_0(int cpu,u64 expires)103 static void mmtimer_setup_int_0(int cpu, u64 expires)
104 {
105 u64 val;
106
107 /* Disable interrupt */
108 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC1_INT_ENABLE), 0UL);
109
110 /* Initialize comparator value */
111 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPB), -1L);
112
113 /* Clear pending bit */
114 mmtimer_clr_int_pending(0);
115
116 val = ((u64)SGI_MMTIMER_VECTOR << SH_RTC1_INT_CONFIG_IDX_SHFT) |
117 ((u64)cpu_physical_id(cpu) <<
118 SH_RTC1_INT_CONFIG_PID_SHFT);
119
120 /* Set configuration */
121 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC1_INT_CONFIG), val);
122
123 /* Enable RTC interrupts */
124 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC1_INT_ENABLE), 1UL);
125
126 /* Initialize comparator value */
127 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPB), expires);
128
129
130 }
131
132 /* Setup timer on comparator RTC2 */
mmtimer_setup_int_1(int cpu,u64 expires)133 static void mmtimer_setup_int_1(int cpu, u64 expires)
134 {
135 u64 val;
136
137 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC2_INT_ENABLE), 0UL);
138
139 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPC), -1L);
140
141 mmtimer_clr_int_pending(1);
142
143 val = ((u64)SGI_MMTIMER_VECTOR << SH_RTC2_INT_CONFIG_IDX_SHFT) |
144 ((u64)cpu_physical_id(cpu) <<
145 SH_RTC2_INT_CONFIG_PID_SHFT);
146
147 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC2_INT_CONFIG), val);
148
149 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC2_INT_ENABLE), 1UL);
150
151 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPC), expires);
152 }
153
154 /* Setup timer on comparator RTC3 */
mmtimer_setup_int_2(int cpu,u64 expires)155 static void mmtimer_setup_int_2(int cpu, u64 expires)
156 {
157 u64 val;
158
159 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC3_INT_ENABLE), 0UL);
160
161 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPD), -1L);
162
163 mmtimer_clr_int_pending(2);
164
165 val = ((u64)SGI_MMTIMER_VECTOR << SH_RTC3_INT_CONFIG_IDX_SHFT) |
166 ((u64)cpu_physical_id(cpu) <<
167 SH_RTC3_INT_CONFIG_PID_SHFT);
168
169 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC3_INT_CONFIG), val);
170
171 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC3_INT_ENABLE), 1UL);
172
173 HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPD), expires);
174 }
175
176 /*
177 * This function must be called with interrupts disabled and preemption off
178 * in order to insure that the setup succeeds in a deterministic time frame.
179 * It will check if the interrupt setup succeeded.
180 */
mmtimer_setup(int cpu,int comparator,unsigned long expires,u64 * set_completion_time)181 static int mmtimer_setup(int cpu, int comparator, unsigned long expires,
182 u64 *set_completion_time)
183 {
184 switch (comparator) {
185 case 0:
186 mmtimer_setup_int_0(cpu, expires);
187 break;
188 case 1:
189 mmtimer_setup_int_1(cpu, expires);
190 break;
191 case 2:
192 mmtimer_setup_int_2(cpu, expires);
193 break;
194 }
195 /* We might've missed our expiration time */
196 *set_completion_time = rtc_time();
197 if (*set_completion_time <= expires)
198 return 1;
199
200 /*
201 * If an interrupt is already pending then its okay
202 * if not then we failed
203 */
204 return mmtimer_int_pending(comparator);
205 }
206
mmtimer_disable_int(long nasid,int comparator)207 static int mmtimer_disable_int(long nasid, int comparator)
208 {
209 switch (comparator) {
210 case 0:
211 nasid == -1 ? HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC1_INT_ENABLE),
212 0UL) : REMOTE_HUB_S(nasid, SH_RTC1_INT_ENABLE, 0UL);
213 break;
214 case 1:
215 nasid == -1 ? HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC2_INT_ENABLE),
216 0UL) : REMOTE_HUB_S(nasid, SH_RTC2_INT_ENABLE, 0UL);
217 break;
218 case 2:
219 nasid == -1 ? HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC3_INT_ENABLE),
220 0UL) : REMOTE_HUB_S(nasid, SH_RTC3_INT_ENABLE, 0UL);
221 break;
222 default:
223 return -EFAULT;
224 }
225 return 0;
226 }
227
228 #define COMPARATOR 1 /* The comparator to use */
229
230 #define TIMER_OFF 0xbadcabLL /* Timer is not setup */
231 #define TIMER_SET 0 /* Comparator is set for this timer */
232
233 #define MMTIMER_INTERVAL_RETRY_INCREMENT_DEFAULT 40
234
235 /* There is one of these for each timer */
236 struct mmtimer {
237 struct rb_node list;
238 struct k_itimer *timer;
239 int cpu;
240 };
241
242 struct mmtimer_node {
243 spinlock_t lock ____cacheline_aligned;
244 struct rb_root timer_head;
245 struct rb_node *next;
246 struct tasklet_struct tasklet;
247 };
248 static struct mmtimer_node *timers;
249
250 static unsigned mmtimer_interval_retry_increment =
251 MMTIMER_INTERVAL_RETRY_INCREMENT_DEFAULT;
252 module_param(mmtimer_interval_retry_increment, uint, 0644);
253 MODULE_PARM_DESC(mmtimer_interval_retry_increment,
254 "RTC ticks to add to expiration on interval retry (default 40)");
255
256 /*
257 * Add a new mmtimer struct to the node's mmtimer list.
258 * This function assumes the struct mmtimer_node is locked.
259 */
mmtimer_add_list(struct mmtimer * n)260 static void mmtimer_add_list(struct mmtimer *n)
261 {
262 int nodeid = n->timer->it.mmtimer.node;
263 unsigned long expires = n->timer->it.mmtimer.expires;
264 struct rb_node **link = &timers[nodeid].timer_head.rb_node;
265 struct rb_node *parent = NULL;
266 struct mmtimer *x;
267
268 /*
269 * Find the right place in the rbtree:
270 */
271 while (*link) {
272 parent = *link;
273 x = rb_entry(parent, struct mmtimer, list);
274
275 if (expires < x->timer->it.mmtimer.expires)
276 link = &(*link)->rb_left;
277 else
278 link = &(*link)->rb_right;
279 }
280
281 /*
282 * Insert the timer to the rbtree and check whether it
283 * replaces the first pending timer
284 */
285 rb_link_node(&n->list, parent, link);
286 rb_insert_color(&n->list, &timers[nodeid].timer_head);
287
288 if (!timers[nodeid].next || expires < rb_entry(timers[nodeid].next,
289 struct mmtimer, list)->timer->it.mmtimer.expires)
290 timers[nodeid].next = &n->list;
291 }
292
293 /*
294 * Set the comparator for the next timer.
295 * This function assumes the struct mmtimer_node is locked.
296 */
mmtimer_set_next_timer(int nodeid)297 static void mmtimer_set_next_timer(int nodeid)
298 {
299 struct mmtimer_node *n = &timers[nodeid];
300 struct mmtimer *x;
301 struct k_itimer *t;
302 u64 expires, exp, set_completion_time;
303 int i;
304
305 restart:
306 if (n->next == NULL)
307 return;
308
309 x = rb_entry(n->next, struct mmtimer, list);
310 t = x->timer;
311 if (!t->it.mmtimer.incr) {
312 /* Not an interval timer */
313 if (!mmtimer_setup(x->cpu, COMPARATOR,
314 t->it.mmtimer.expires,
315 &set_completion_time)) {
316 /* Late setup, fire now */
317 tasklet_schedule(&n->tasklet);
318 }
319 return;
320 }
321
322 /* Interval timer */
323 i = 0;
324 expires = exp = t->it.mmtimer.expires;
325 while (!mmtimer_setup(x->cpu, COMPARATOR, expires,
326 &set_completion_time)) {
327 int to;
328
329 i++;
330 expires = set_completion_time +
331 mmtimer_interval_retry_increment + (1 << i);
332 /* Calculate overruns as we go. */
333 to = ((u64)(expires - exp) / t->it.mmtimer.incr);
334 if (to) {
335 t->it_overrun += to;
336 t->it.mmtimer.expires += t->it.mmtimer.incr * to;
337 exp = t->it.mmtimer.expires;
338 }
339 if (i > 20) {
340 printk(KERN_ALERT "mmtimer: cannot reschedule timer\n");
341 t->it.mmtimer.clock = TIMER_OFF;
342 n->next = rb_next(&x->list);
343 rb_erase(&x->list, &n->timer_head);
344 kfree(x);
345 goto restart;
346 }
347 }
348 }
349
350 /**
351 * mmtimer_ioctl - ioctl interface for /dev/mmtimer
352 * @file: file structure for the device
353 * @cmd: command to execute
354 * @arg: optional argument to command
355 *
356 * Executes the command specified by @cmd. Returns 0 for success, < 0 for
357 * failure.
358 *
359 * Valid commands:
360 *
361 * %MMTIMER_GETOFFSET - Should return the offset (relative to the start
362 * of the page where the registers are mapped) for the counter in question.
363 *
364 * %MMTIMER_GETRES - Returns the resolution of the clock in femto (10^-15)
365 * seconds
366 *
367 * %MMTIMER_GETFREQ - Copies the frequency of the clock in Hz to the address
368 * specified by @arg
369 *
370 * %MMTIMER_GETBITS - Returns the number of bits in the clock's counter
371 *
372 * %MMTIMER_MMAPAVAIL - Returns 1 if the registers can be mmap'd into userspace
373 *
374 * %MMTIMER_GETCOUNTER - Gets the current value in the counter and places it
375 * in the address specified by @arg.
376 */
mmtimer_ioctl(struct file * file,unsigned int cmd,unsigned long arg)377 static long mmtimer_ioctl(struct file *file, unsigned int cmd,
378 unsigned long arg)
379 {
380 int ret = 0;
381
382 mutex_lock(&mmtimer_mutex);
383
384 switch (cmd) {
385 case MMTIMER_GETOFFSET: /* offset of the counter */
386 /*
387 * SN RTC registers are on their own 64k page
388 */
389 if(PAGE_SIZE <= (1 << 16))
390 ret = (((long)RTC_COUNTER_ADDR) & (PAGE_SIZE-1)) / 8;
391 else
392 ret = -ENOSYS;
393 break;
394
395 case MMTIMER_GETRES: /* resolution of the clock in 10^-15 s */
396 if(copy_to_user((unsigned long __user *)arg,
397 &mmtimer_femtoperiod, sizeof(unsigned long)))
398 ret = -EFAULT;
399 break;
400
401 case MMTIMER_GETFREQ: /* frequency in Hz */
402 if(copy_to_user((unsigned long __user *)arg,
403 &sn_rtc_cycles_per_second,
404 sizeof(unsigned long)))
405 ret = -EFAULT;
406 break;
407
408 case MMTIMER_GETBITS: /* number of bits in the clock */
409 ret = RTC_BITS;
410 break;
411
412 case MMTIMER_MMAPAVAIL: /* can we mmap the clock into userspace? */
413 ret = (PAGE_SIZE <= (1 << 16)) ? 1 : 0;
414 break;
415
416 case MMTIMER_GETCOUNTER:
417 if(copy_to_user((unsigned long __user *)arg,
418 RTC_COUNTER_ADDR, sizeof(unsigned long)))
419 ret = -EFAULT;
420 break;
421 default:
422 ret = -ENOTTY;
423 break;
424 }
425 mutex_unlock(&mmtimer_mutex);
426 return ret;
427 }
428
429 /**
430 * mmtimer_mmap - maps the clock's registers into userspace
431 * @file: file structure for the device
432 * @vma: VMA to map the registers into
433 *
434 * Calls remap_pfn_range() to map the clock's registers into
435 * the calling process' address space.
436 */
mmtimer_mmap(struct file * file,struct vm_area_struct * vma)437 static int mmtimer_mmap(struct file *file, struct vm_area_struct *vma)
438 {
439 unsigned long mmtimer_addr;
440
441 if (vma->vm_end - vma->vm_start != PAGE_SIZE)
442 return -EINVAL;
443
444 if (vma->vm_flags & VM_WRITE)
445 return -EPERM;
446
447 if (PAGE_SIZE > (1 << 16))
448 return -ENOSYS;
449
450 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
451
452 mmtimer_addr = __pa(RTC_COUNTER_ADDR);
453 mmtimer_addr &= ~(PAGE_SIZE - 1);
454 mmtimer_addr &= 0xfffffffffffffffUL;
455
456 if (remap_pfn_range(vma, vma->vm_start, mmtimer_addr >> PAGE_SHIFT,
457 PAGE_SIZE, vma->vm_page_prot)) {
458 printk(KERN_ERR "remap_pfn_range failed in mmtimer.c\n");
459 return -EAGAIN;
460 }
461
462 return 0;
463 }
464
465 static struct miscdevice mmtimer_miscdev = {
466 SGI_MMTIMER,
467 MMTIMER_NAME,
468 &mmtimer_fops
469 };
470
471 static struct timespec sgi_clock_offset;
472 static int sgi_clock_period;
473
474 /*
475 * Posix Timer Interface
476 */
477
478 static struct timespec sgi_clock_offset;
479 static int sgi_clock_period;
480
sgi_clock_get(clockid_t clockid,struct timespec * tp)481 static int sgi_clock_get(clockid_t clockid, struct timespec *tp)
482 {
483 u64 nsec;
484
485 nsec = rtc_time() * sgi_clock_period
486 + sgi_clock_offset.tv_nsec;
487 *tp = ns_to_timespec(nsec);
488 tp->tv_sec += sgi_clock_offset.tv_sec;
489 return 0;
490 };
491
sgi_clock_set(const clockid_t clockid,const struct timespec * tp)492 static int sgi_clock_set(const clockid_t clockid, const struct timespec *tp)
493 {
494
495 u64 nsec;
496 u32 rem;
497
498 nsec = rtc_time() * sgi_clock_period;
499
500 sgi_clock_offset.tv_sec = tp->tv_sec - div_u64_rem(nsec, NSEC_PER_SEC, &rem);
501
502 if (rem <= tp->tv_nsec)
503 sgi_clock_offset.tv_nsec = tp->tv_sec - rem;
504 else {
505 sgi_clock_offset.tv_nsec = tp->tv_sec + NSEC_PER_SEC - rem;
506 sgi_clock_offset.tv_sec--;
507 }
508 return 0;
509 }
510
511 /**
512 * mmtimer_interrupt - timer interrupt handler
513 * @irq: irq received
514 * @dev_id: device the irq came from
515 *
516 * Called when one of the comarators matches the counter, This
517 * routine will send signals to processes that have requested
518 * them.
519 *
520 * This interrupt is run in an interrupt context
521 * by the SHUB. It is therefore safe to locally access SHub
522 * registers.
523 */
524 static irqreturn_t
mmtimer_interrupt(int irq,void * dev_id)525 mmtimer_interrupt(int irq, void *dev_id)
526 {
527 unsigned long expires = 0;
528 int result = IRQ_NONE;
529 unsigned indx = cpu_to_node(smp_processor_id());
530 struct mmtimer *base;
531
532 spin_lock(&timers[indx].lock);
533 base = rb_entry(timers[indx].next, struct mmtimer, list);
534 if (base == NULL) {
535 spin_unlock(&timers[indx].lock);
536 return result;
537 }
538
539 if (base->cpu == smp_processor_id()) {
540 if (base->timer)
541 expires = base->timer->it.mmtimer.expires;
542 /* expires test won't work with shared irqs */
543 if ((mmtimer_int_pending(COMPARATOR) > 0) ||
544 (expires && (expires <= rtc_time()))) {
545 mmtimer_clr_int_pending(COMPARATOR);
546 tasklet_schedule(&timers[indx].tasklet);
547 result = IRQ_HANDLED;
548 }
549 }
550 spin_unlock(&timers[indx].lock);
551 return result;
552 }
553
mmtimer_tasklet(unsigned long data)554 static void mmtimer_tasklet(unsigned long data)
555 {
556 int nodeid = data;
557 struct mmtimer_node *mn = &timers[nodeid];
558 struct mmtimer *x;
559 struct k_itimer *t;
560 unsigned long flags;
561
562 /* Send signal and deal with periodic signals */
563 spin_lock_irqsave(&mn->lock, flags);
564 if (!mn->next)
565 goto out;
566
567 x = rb_entry(mn->next, struct mmtimer, list);
568 t = x->timer;
569
570 if (t->it.mmtimer.clock == TIMER_OFF)
571 goto out;
572
573 t->it_overrun = 0;
574
575 mn->next = rb_next(&x->list);
576 rb_erase(&x->list, &mn->timer_head);
577
578 if (posix_timer_event(t, 0) != 0)
579 t->it_overrun++;
580
581 if(t->it.mmtimer.incr) {
582 t->it.mmtimer.expires += t->it.mmtimer.incr;
583 mmtimer_add_list(x);
584 } else {
585 /* Ensure we don't false trigger in mmtimer_interrupt */
586 t->it.mmtimer.clock = TIMER_OFF;
587 t->it.mmtimer.expires = 0;
588 kfree(x);
589 }
590 /* Set comparator for next timer, if there is one */
591 mmtimer_set_next_timer(nodeid);
592
593 t->it_overrun_last = t->it_overrun;
594 out:
595 spin_unlock_irqrestore(&mn->lock, flags);
596 }
597
sgi_timer_create(struct k_itimer * timer)598 static int sgi_timer_create(struct k_itimer *timer)
599 {
600 /* Insure that a newly created timer is off */
601 timer->it.mmtimer.clock = TIMER_OFF;
602 return 0;
603 }
604
605 /* This does not really delete a timer. It just insures
606 * that the timer is not active
607 *
608 * Assumption: it_lock is already held with irq's disabled
609 */
sgi_timer_del(struct k_itimer * timr)610 static int sgi_timer_del(struct k_itimer *timr)
611 {
612 cnodeid_t nodeid = timr->it.mmtimer.node;
613 unsigned long irqflags;
614
615 spin_lock_irqsave(&timers[nodeid].lock, irqflags);
616 if (timr->it.mmtimer.clock != TIMER_OFF) {
617 unsigned long expires = timr->it.mmtimer.expires;
618 struct rb_node *n = timers[nodeid].timer_head.rb_node;
619 struct mmtimer *uninitialized_var(t);
620 int r = 0;
621
622 timr->it.mmtimer.clock = TIMER_OFF;
623 timr->it.mmtimer.expires = 0;
624
625 while (n) {
626 t = rb_entry(n, struct mmtimer, list);
627 if (t->timer == timr)
628 break;
629
630 if (expires < t->timer->it.mmtimer.expires)
631 n = n->rb_left;
632 else
633 n = n->rb_right;
634 }
635
636 if (!n) {
637 spin_unlock_irqrestore(&timers[nodeid].lock, irqflags);
638 return 0;
639 }
640
641 if (timers[nodeid].next == n) {
642 timers[nodeid].next = rb_next(n);
643 r = 1;
644 }
645
646 rb_erase(n, &timers[nodeid].timer_head);
647 kfree(t);
648
649 if (r) {
650 mmtimer_disable_int(cnodeid_to_nasid(nodeid),
651 COMPARATOR);
652 mmtimer_set_next_timer(nodeid);
653 }
654 }
655 spin_unlock_irqrestore(&timers[nodeid].lock, irqflags);
656 return 0;
657 }
658
659 /* Assumption: it_lock is already held with irq's disabled */
sgi_timer_get(struct k_itimer * timr,struct itimerspec * cur_setting)660 static void sgi_timer_get(struct k_itimer *timr, struct itimerspec *cur_setting)
661 {
662
663 if (timr->it.mmtimer.clock == TIMER_OFF) {
664 cur_setting->it_interval.tv_nsec = 0;
665 cur_setting->it_interval.tv_sec = 0;
666 cur_setting->it_value.tv_nsec = 0;
667 cur_setting->it_value.tv_sec =0;
668 return;
669 }
670
671 cur_setting->it_interval = ns_to_timespec(timr->it.mmtimer.incr * sgi_clock_period);
672 cur_setting->it_value = ns_to_timespec((timr->it.mmtimer.expires - rtc_time()) * sgi_clock_period);
673 }
674
675
sgi_timer_set(struct k_itimer * timr,int flags,struct itimerspec * new_setting,struct itimerspec * old_setting)676 static int sgi_timer_set(struct k_itimer *timr, int flags,
677 struct itimerspec * new_setting,
678 struct itimerspec * old_setting)
679 {
680 unsigned long when, period, irqflags;
681 int err = 0;
682 cnodeid_t nodeid;
683 struct mmtimer *base;
684 struct rb_node *n;
685
686 if (old_setting)
687 sgi_timer_get(timr, old_setting);
688
689 sgi_timer_del(timr);
690 when = timespec_to_ns(&new_setting->it_value);
691 period = timespec_to_ns(&new_setting->it_interval);
692
693 if (when == 0)
694 /* Clear timer */
695 return 0;
696
697 base = kmalloc(sizeof(struct mmtimer), GFP_KERNEL);
698 if (base == NULL)
699 return -ENOMEM;
700
701 if (flags & TIMER_ABSTIME) {
702 struct timespec n;
703 unsigned long now;
704
705 getnstimeofday(&n);
706 now = timespec_to_ns(&n);
707 if (when > now)
708 when -= now;
709 else
710 /* Fire the timer immediately */
711 when = 0;
712 }
713
714 /*
715 * Convert to sgi clock period. Need to keep rtc_time() as near as possible
716 * to getnstimeofday() in order to be as faithful as possible to the time
717 * specified.
718 */
719 when = (when + sgi_clock_period - 1) / sgi_clock_period + rtc_time();
720 period = (period + sgi_clock_period - 1) / sgi_clock_period;
721
722 /*
723 * We are allocating a local SHub comparator. If we would be moved to another
724 * cpu then another SHub may be local to us. Prohibit that by switching off
725 * preemption.
726 */
727 preempt_disable();
728
729 nodeid = cpu_to_node(smp_processor_id());
730
731 /* Lock the node timer structure */
732 spin_lock_irqsave(&timers[nodeid].lock, irqflags);
733
734 base->timer = timr;
735 base->cpu = smp_processor_id();
736
737 timr->it.mmtimer.clock = TIMER_SET;
738 timr->it.mmtimer.node = nodeid;
739 timr->it.mmtimer.incr = period;
740 timr->it.mmtimer.expires = when;
741
742 n = timers[nodeid].next;
743
744 /* Add the new struct mmtimer to node's timer list */
745 mmtimer_add_list(base);
746
747 if (timers[nodeid].next == n) {
748 /* No need to reprogram comparator for now */
749 spin_unlock_irqrestore(&timers[nodeid].lock, irqflags);
750 preempt_enable();
751 return err;
752 }
753
754 /* We need to reprogram the comparator */
755 if (n)
756 mmtimer_disable_int(cnodeid_to_nasid(nodeid), COMPARATOR);
757
758 mmtimer_set_next_timer(nodeid);
759
760 /* Unlock the node timer structure */
761 spin_unlock_irqrestore(&timers[nodeid].lock, irqflags);
762
763 preempt_enable();
764
765 return err;
766 }
767
sgi_clock_getres(const clockid_t which_clock,struct timespec * tp)768 static int sgi_clock_getres(const clockid_t which_clock, struct timespec *tp)
769 {
770 tp->tv_sec = 0;
771 tp->tv_nsec = sgi_clock_period;
772 return 0;
773 }
774
775 static struct k_clock sgi_clock = {
776 .clock_set = sgi_clock_set,
777 .clock_get = sgi_clock_get,
778 .clock_getres = sgi_clock_getres,
779 .timer_create = sgi_timer_create,
780 .timer_set = sgi_timer_set,
781 .timer_del = sgi_timer_del,
782 .timer_get = sgi_timer_get
783 };
784
785 /**
786 * mmtimer_init - device initialization routine
787 *
788 * Does initial setup for the mmtimer device.
789 */
mmtimer_init(void)790 static int __init mmtimer_init(void)
791 {
792 cnodeid_t node, maxn = -1;
793
794 if (!ia64_platform_is("sn2"))
795 return 0;
796
797 /*
798 * Sanity check the cycles/sec variable
799 */
800 if (sn_rtc_cycles_per_second < 100000) {
801 printk(KERN_ERR "%s: unable to determine clock frequency\n",
802 MMTIMER_NAME);
803 goto out1;
804 }
805
806 mmtimer_femtoperiod = ((unsigned long)1E15 + sn_rtc_cycles_per_second /
807 2) / sn_rtc_cycles_per_second;
808
809 if (request_irq(SGI_MMTIMER_VECTOR, mmtimer_interrupt, IRQF_PERCPU, MMTIMER_NAME, NULL)) {
810 printk(KERN_WARNING "%s: unable to allocate interrupt.",
811 MMTIMER_NAME);
812 goto out1;
813 }
814
815 if (misc_register(&mmtimer_miscdev)) {
816 printk(KERN_ERR "%s: failed to register device\n",
817 MMTIMER_NAME);
818 goto out2;
819 }
820
821 /* Get max numbered node, calculate slots needed */
822 for_each_online_node(node) {
823 maxn = node;
824 }
825 maxn++;
826
827 /* Allocate list of node ptrs to mmtimer_t's */
828 timers = kzalloc(sizeof(struct mmtimer_node)*maxn, GFP_KERNEL);
829 if (!timers) {
830 printk(KERN_ERR "%s: failed to allocate memory for device\n",
831 MMTIMER_NAME);
832 goto out3;
833 }
834
835 /* Initialize struct mmtimer's for each online node */
836 for_each_online_node(node) {
837 spin_lock_init(&timers[node].lock);
838 tasklet_init(&timers[node].tasklet, mmtimer_tasklet,
839 (unsigned long) node);
840 }
841
842 sgi_clock_period = NSEC_PER_SEC / sn_rtc_cycles_per_second;
843 posix_timers_register_clock(CLOCK_SGI_CYCLE, &sgi_clock);
844
845 printk(KERN_INFO "%s: v%s, %ld MHz\n", MMTIMER_DESC, MMTIMER_VERSION,
846 sn_rtc_cycles_per_second/(unsigned long)1E6);
847
848 return 0;
849
850 out3:
851 misc_deregister(&mmtimer_miscdev);
852 out2:
853 free_irq(SGI_MMTIMER_VECTOR, NULL);
854 out1:
855 return -1;
856 }
857
858 module_init(mmtimer_init);
859