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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/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 */ | |
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 */ | |
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 */ | |
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 */ | |
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 */ | |
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 | */ | |
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 | ||
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 | */ | |
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 | */ | |
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 | */ | |
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 | */ | |
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 | ||
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 | ||
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 | |
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 | ||
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 | ||
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 | */ | |
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 */ | |
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 | ||
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 | ||
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 | */ | |
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); |