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1/*
2 * linux/arch/ia64/kernel/time.c
3 *
4 * Copyright (C) 1998-2003 Hewlett-Packard Co
5 * Stephane Eranian <eranian@hpl.hp.com>
6 * David Mosberger <davidm@hpl.hp.com>
7 * Copyright (C) 1999 Don Dugger <don.dugger@intel.com>
8 * Copyright (C) 1999-2000 VA Linux Systems
9 * Copyright (C) 1999-2000 Walt Drummond <drummond@valinux.com>
10 */
11
12#include <linux/cpu.h>
13#include <linux/init.h>
14#include <linux/kernel.h>
15#include <linux/module.h>
16#include <linux/profile.h>
17#include <linux/sched.h>
18#include <linux/time.h>
19#include <linux/interrupt.h>
20#include <linux/efi.h>
21#include <linux/timex.h>
22#include <linux/timekeeper_internal.h>
23#include <linux/platform_device.h>
24
25#include <asm/machvec.h>
26#include <asm/delay.h>
27#include <asm/hw_irq.h>
28#include <asm/paravirt.h>
29#include <asm/ptrace.h>
30#include <asm/sal.h>
31#include <asm/sections.h>
32
33#include "fsyscall_gtod_data.h"
34
35static cycle_t itc_get_cycles(struct clocksource *cs);
36
37struct fsyscall_gtod_data_t fsyscall_gtod_data;
38
39struct itc_jitter_data_t itc_jitter_data;
40
41volatile int time_keeper_id = 0; /* smp_processor_id() of time-keeper */
42
43#ifdef CONFIG_IA64_DEBUG_IRQ
44
45unsigned long last_cli_ip;
46EXPORT_SYMBOL(last_cli_ip);
47
48#endif
49
50#ifdef CONFIG_PARAVIRT
51/* We need to define a real function for sched_clock, to override the
52 weak default version */
53unsigned long long sched_clock(void)
54{
55 return paravirt_sched_clock();
56}
57#endif
58
59#ifdef CONFIG_PARAVIRT
60static void
61paravirt_clocksource_resume(struct clocksource *cs)
62{
63 if (pv_time_ops.clocksource_resume)
64 pv_time_ops.clocksource_resume();
65}
66#endif
67
68static struct clocksource clocksource_itc = {
69 .name = "itc",
70 .rating = 350,
71 .read = itc_get_cycles,
72 .mask = CLOCKSOURCE_MASK(64),
73 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
74#ifdef CONFIG_PARAVIRT
75 .resume = paravirt_clocksource_resume,
76#endif
77};
78static struct clocksource *itc_clocksource;
79
80#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
81
82#include <linux/kernel_stat.h>
83
84extern cputime_t cycle_to_cputime(u64 cyc);
85
86void vtime_account_user(struct task_struct *tsk)
87{
88 cputime_t delta_utime;
89 struct thread_info *ti = task_thread_info(tsk);
90
91 if (ti->ac_utime) {
92 delta_utime = cycle_to_cputime(ti->ac_utime);
93 account_user_time(tsk, delta_utime, delta_utime);
94 ti->ac_utime = 0;
95 }
96}
97
98/*
99 * Called from the context switch with interrupts disabled, to charge all
100 * accumulated times to the current process, and to prepare accounting on
101 * the next process.
102 */
103void arch_vtime_task_switch(struct task_struct *prev)
104{
105 struct thread_info *pi = task_thread_info(prev);
106 struct thread_info *ni = task_thread_info(current);
107
108 pi->ac_stamp = ni->ac_stamp;
109 ni->ac_stime = ni->ac_utime = 0;
110}
111
112/*
113 * Account time for a transition between system, hard irq or soft irq state.
114 * Note that this function is called with interrupts enabled.
115 */
116static cputime_t vtime_delta(struct task_struct *tsk)
117{
118 struct thread_info *ti = task_thread_info(tsk);
119 cputime_t delta_stime;
120 __u64 now;
121
122 WARN_ON_ONCE(!irqs_disabled());
123
124 now = ia64_get_itc();
125
126 delta_stime = cycle_to_cputime(ti->ac_stime + (now - ti->ac_stamp));
127 ti->ac_stime = 0;
128 ti->ac_stamp = now;
129
130 return delta_stime;
131}
132
133void vtime_account_system(struct task_struct *tsk)
134{
135 cputime_t delta = vtime_delta(tsk);
136
137 account_system_time(tsk, 0, delta, delta);
138}
139EXPORT_SYMBOL_GPL(vtime_account_system);
140
141void vtime_account_idle(struct task_struct *tsk)
142{
143 account_idle_time(vtime_delta(tsk));
144}
145
146#endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
147
148static irqreturn_t
149timer_interrupt (int irq, void *dev_id)
150{
151 unsigned long new_itm;
152
153 if (cpu_is_offline(smp_processor_id())) {
154 return IRQ_HANDLED;
155 }
156
157 platform_timer_interrupt(irq, dev_id);
158
159 new_itm = local_cpu_data->itm_next;
160
161 if (!time_after(ia64_get_itc(), new_itm))
162 printk(KERN_ERR "Oops: timer tick before it's due (itc=%lx,itm=%lx)\n",
163 ia64_get_itc(), new_itm);
164
165 profile_tick(CPU_PROFILING);
166
167 if (paravirt_do_steal_accounting(&new_itm))
168 goto skip_process_time_accounting;
169
170 while (1) {
171 update_process_times(user_mode(get_irq_regs()));
172
173 new_itm += local_cpu_data->itm_delta;
174
175 if (smp_processor_id() == time_keeper_id)
176 xtime_update(1);
177
178 local_cpu_data->itm_next = new_itm;
179
180 if (time_after(new_itm, ia64_get_itc()))
181 break;
182
183 /*
184 * Allow IPIs to interrupt the timer loop.
185 */
186 local_irq_enable();
187 local_irq_disable();
188 }
189
190skip_process_time_accounting:
191
192 do {
193 /*
194 * If we're too close to the next clock tick for
195 * comfort, we increase the safety margin by
196 * intentionally dropping the next tick(s). We do NOT
197 * update itm.next because that would force us to call
198 * xtime_update() which in turn would let our clock run
199 * too fast (with the potentially devastating effect
200 * of losing monotony of time).
201 */
202 while (!time_after(new_itm, ia64_get_itc() + local_cpu_data->itm_delta/2))
203 new_itm += local_cpu_data->itm_delta;
204 ia64_set_itm(new_itm);
205 /* double check, in case we got hit by a (slow) PMI: */
206 } while (time_after_eq(ia64_get_itc(), new_itm));
207 return IRQ_HANDLED;
208}
209
210/*
211 * Encapsulate access to the itm structure for SMP.
212 */
213void
214ia64_cpu_local_tick (void)
215{
216 int cpu = smp_processor_id();
217 unsigned long shift = 0, delta;
218
219 /* arrange for the cycle counter to generate a timer interrupt: */
220 ia64_set_itv(IA64_TIMER_VECTOR);
221
222 delta = local_cpu_data->itm_delta;
223 /*
224 * Stagger the timer tick for each CPU so they don't occur all at (almost) the
225 * same time:
226 */
227 if (cpu) {
228 unsigned long hi = 1UL << ia64_fls(cpu);
229 shift = (2*(cpu - hi) + 1) * delta/hi/2;
230 }
231 local_cpu_data->itm_next = ia64_get_itc() + delta + shift;
232 ia64_set_itm(local_cpu_data->itm_next);
233}
234
235static int nojitter;
236
237static int __init nojitter_setup(char *str)
238{
239 nojitter = 1;
240 printk("Jitter checking for ITC timers disabled\n");
241 return 1;
242}
243
244__setup("nojitter", nojitter_setup);
245
246
247void ia64_init_itm(void)
248{
249 unsigned long platform_base_freq, itc_freq;
250 struct pal_freq_ratio itc_ratio, proc_ratio;
251 long status, platform_base_drift, itc_drift;
252
253 /*
254 * According to SAL v2.6, we need to use a SAL call to determine the platform base
255 * frequency and then a PAL call to determine the frequency ratio between the ITC
256 * and the base frequency.
257 */
258 status = ia64_sal_freq_base(SAL_FREQ_BASE_PLATFORM,
259 &platform_base_freq, &platform_base_drift);
260 if (status != 0) {
261 printk(KERN_ERR "SAL_FREQ_BASE_PLATFORM failed: %s\n", ia64_sal_strerror(status));
262 } else {
263 status = ia64_pal_freq_ratios(&proc_ratio, NULL, &itc_ratio);
264 if (status != 0)
265 printk(KERN_ERR "PAL_FREQ_RATIOS failed with status=%ld\n", status);
266 }
267 if (status != 0) {
268 /* invent "random" values */
269 printk(KERN_ERR
270 "SAL/PAL failed to obtain frequency info---inventing reasonable values\n");
271 platform_base_freq = 100000000;
272 platform_base_drift = -1; /* no drift info */
273 itc_ratio.num = 3;
274 itc_ratio.den = 1;
275 }
276 if (platform_base_freq < 40000000) {
277 printk(KERN_ERR "Platform base frequency %lu bogus---resetting to 75MHz!\n",
278 platform_base_freq);
279 platform_base_freq = 75000000;
280 platform_base_drift = -1;
281 }
282 if (!proc_ratio.den)
283 proc_ratio.den = 1; /* avoid division by zero */
284 if (!itc_ratio.den)
285 itc_ratio.den = 1; /* avoid division by zero */
286
287 itc_freq = (platform_base_freq*itc_ratio.num)/itc_ratio.den;
288
289 local_cpu_data->itm_delta = (itc_freq + HZ/2) / HZ;
290 printk(KERN_DEBUG "CPU %d: base freq=%lu.%03luMHz, ITC ratio=%u/%u, "
291 "ITC freq=%lu.%03luMHz", smp_processor_id(),
292 platform_base_freq / 1000000, (platform_base_freq / 1000) % 1000,
293 itc_ratio.num, itc_ratio.den, itc_freq / 1000000, (itc_freq / 1000) % 1000);
294
295 if (platform_base_drift != -1) {
296 itc_drift = platform_base_drift*itc_ratio.num/itc_ratio.den;
297 printk("+/-%ldppm\n", itc_drift);
298 } else {
299 itc_drift = -1;
300 printk("\n");
301 }
302
303 local_cpu_data->proc_freq = (platform_base_freq*proc_ratio.num)/proc_ratio.den;
304 local_cpu_data->itc_freq = itc_freq;
305 local_cpu_data->cyc_per_usec = (itc_freq + USEC_PER_SEC/2) / USEC_PER_SEC;
306 local_cpu_data->nsec_per_cyc = ((NSEC_PER_SEC<<IA64_NSEC_PER_CYC_SHIFT)
307 + itc_freq/2)/itc_freq;
308
309 if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT)) {
310#ifdef CONFIG_SMP
311 /* On IA64 in an SMP configuration ITCs are never accurately synchronized.
312 * Jitter compensation requires a cmpxchg which may limit
313 * the scalability of the syscalls for retrieving time.
314 * The ITC synchronization is usually successful to within a few
315 * ITC ticks but this is not a sure thing. If you need to improve
316 * timer performance in SMP situations then boot the kernel with the
317 * "nojitter" option. However, doing so may result in time fluctuating (maybe
318 * even going backward) if the ITC offsets between the individual CPUs
319 * are too large.
320 */
321 if (!nojitter)
322 itc_jitter_data.itc_jitter = 1;
323#endif
324 } else
325 /*
326 * ITC is drifty and we have not synchronized the ITCs in smpboot.c.
327 * ITC values may fluctuate significantly between processors.
328 * Clock should not be used for hrtimers. Mark itc as only
329 * useful for boot and testing.
330 *
331 * Note that jitter compensation is off! There is no point of
332 * synchronizing ITCs since they may be large differentials
333 * that change over time.
334 *
335 * The only way to fix this would be to repeatedly sync the
336 * ITCs. Until that time we have to avoid ITC.
337 */
338 clocksource_itc.rating = 50;
339
340 paravirt_init_missing_ticks_accounting(smp_processor_id());
341
342 /* avoid softlock up message when cpu is unplug and plugged again. */
343 touch_softlockup_watchdog();
344
345 /* Setup the CPU local timer tick */
346 ia64_cpu_local_tick();
347
348 if (!itc_clocksource) {
349 clocksource_register_hz(&clocksource_itc,
350 local_cpu_data->itc_freq);
351 itc_clocksource = &clocksource_itc;
352 }
353}
354
355static cycle_t itc_get_cycles(struct clocksource *cs)
356{
357 unsigned long lcycle, now, ret;
358
359 if (!itc_jitter_data.itc_jitter)
360 return get_cycles();
361
362 lcycle = itc_jitter_data.itc_lastcycle;
363 now = get_cycles();
364 if (lcycle && time_after(lcycle, now))
365 return lcycle;
366
367 /*
368 * Keep track of the last timer value returned.
369 * In an SMP environment, you could lose out in contention of
370 * cmpxchg. If so, your cmpxchg returns new value which the
371 * winner of contention updated to. Use the new value instead.
372 */
373 ret = cmpxchg(&itc_jitter_data.itc_lastcycle, lcycle, now);
374 if (unlikely(ret != lcycle))
375 return ret;
376
377 return now;
378}
379
380
381static struct irqaction timer_irqaction = {
382 .handler = timer_interrupt,
383 .flags = IRQF_IRQPOLL,
384 .name = "timer"
385};
386
387static struct platform_device rtc_efi_dev = {
388 .name = "rtc-efi",
389 .id = -1,
390};
391
392static int __init rtc_init(void)
393{
394 if (platform_device_register(&rtc_efi_dev) < 0)
395 printk(KERN_ERR "unable to register rtc device...\n");
396
397 /* not necessarily an error */
398 return 0;
399}
400module_init(rtc_init);
401
402void read_persistent_clock(struct timespec *ts)
403{
404 efi_gettimeofday(ts);
405}
406
407void __init
408time_init (void)
409{
410 register_percpu_irq(IA64_TIMER_VECTOR, &timer_irqaction);
411 ia64_init_itm();
412}
413
414/*
415 * Generic udelay assumes that if preemption is allowed and the thread
416 * migrates to another CPU, that the ITC values are synchronized across
417 * all CPUs.
418 */
419static void
420ia64_itc_udelay (unsigned long usecs)
421{
422 unsigned long start = ia64_get_itc();
423 unsigned long end = start + usecs*local_cpu_data->cyc_per_usec;
424
425 while (time_before(ia64_get_itc(), end))
426 cpu_relax();
427}
428
429void (*ia64_udelay)(unsigned long usecs) = &ia64_itc_udelay;
430
431void
432udelay (unsigned long usecs)
433{
434 (*ia64_udelay)(usecs);
435}
436EXPORT_SYMBOL(udelay);
437
438/* IA64 doesn't cache the timezone */
439void update_vsyscall_tz(void)
440{
441}
442
443void update_vsyscall_old(struct timespec *wall, struct timespec *wtm,
444 struct clocksource *c, u32 mult)
445{
446 write_seqcount_begin(&fsyscall_gtod_data.seq);
447
448 /* copy fsyscall clock data */
449 fsyscall_gtod_data.clk_mask = c->mask;
450 fsyscall_gtod_data.clk_mult = mult;
451 fsyscall_gtod_data.clk_shift = c->shift;
452 fsyscall_gtod_data.clk_fsys_mmio = c->archdata.fsys_mmio;
453 fsyscall_gtod_data.clk_cycle_last = c->cycle_last;
454
455 /* copy kernel time structures */
456 fsyscall_gtod_data.wall_time.tv_sec = wall->tv_sec;
457 fsyscall_gtod_data.wall_time.tv_nsec = wall->tv_nsec;
458 fsyscall_gtod_data.monotonic_time.tv_sec = wtm->tv_sec
459 + wall->tv_sec;
460 fsyscall_gtod_data.monotonic_time.tv_nsec = wtm->tv_nsec
461 + wall->tv_nsec;
462
463 /* normalize */
464 while (fsyscall_gtod_data.monotonic_time.tv_nsec >= NSEC_PER_SEC) {
465 fsyscall_gtod_data.monotonic_time.tv_nsec -= NSEC_PER_SEC;
466 fsyscall_gtod_data.monotonic_time.tv_sec++;
467 }
468
469 write_seqcount_end(&fsyscall_gtod_data.seq);
470}
471
1/*
2 * linux/arch/ia64/kernel/time.c
3 *
4 * Copyright (C) 1998-2003 Hewlett-Packard Co
5 * Stephane Eranian <eranian@hpl.hp.com>
6 * David Mosberger <davidm@hpl.hp.com>
7 * Copyright (C) 1999 Don Dugger <don.dugger@intel.com>
8 * Copyright (C) 1999-2000 VA Linux Systems
9 * Copyright (C) 1999-2000 Walt Drummond <drummond@valinux.com>
10 */
11
12#include <linux/cpu.h>
13#include <linux/init.h>
14#include <linux/kernel.h>
15#include <linux/module.h>
16#include <linux/profile.h>
17#include <linux/sched.h>
18#include <linux/time.h>
19#include <linux/interrupt.h>
20#include <linux/efi.h>
21#include <linux/timex.h>
22#include <linux/timekeeper_internal.h>
23#include <linux/platform_device.h>
24
25#include <asm/machvec.h>
26#include <asm/delay.h>
27#include <asm/hw_irq.h>
28#include <asm/ptrace.h>
29#include <asm/sal.h>
30#include <asm/sections.h>
31
32#include "fsyscall_gtod_data.h"
33
34static cycle_t itc_get_cycles(struct clocksource *cs);
35
36struct fsyscall_gtod_data_t fsyscall_gtod_data;
37
38struct itc_jitter_data_t itc_jitter_data;
39
40volatile int time_keeper_id = 0; /* smp_processor_id() of time-keeper */
41
42#ifdef CONFIG_IA64_DEBUG_IRQ
43
44unsigned long last_cli_ip;
45EXPORT_SYMBOL(last_cli_ip);
46
47#endif
48
49static struct clocksource clocksource_itc = {
50 .name = "itc",
51 .rating = 350,
52 .read = itc_get_cycles,
53 .mask = CLOCKSOURCE_MASK(64),
54 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
55};
56static struct clocksource *itc_clocksource;
57
58#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
59
60#include <linux/kernel_stat.h>
61
62extern cputime_t cycle_to_cputime(u64 cyc);
63
64void vtime_account_user(struct task_struct *tsk)
65{
66 cputime_t delta_utime;
67 struct thread_info *ti = task_thread_info(tsk);
68
69 if (ti->ac_utime) {
70 delta_utime = cycle_to_cputime(ti->ac_utime);
71 account_user_time(tsk, delta_utime, delta_utime);
72 ti->ac_utime = 0;
73 }
74}
75
76/*
77 * Called from the context switch with interrupts disabled, to charge all
78 * accumulated times to the current process, and to prepare accounting on
79 * the next process.
80 */
81void arch_vtime_task_switch(struct task_struct *prev)
82{
83 struct thread_info *pi = task_thread_info(prev);
84 struct thread_info *ni = task_thread_info(current);
85
86 pi->ac_stamp = ni->ac_stamp;
87 ni->ac_stime = ni->ac_utime = 0;
88}
89
90/*
91 * Account time for a transition between system, hard irq or soft irq state.
92 * Note that this function is called with interrupts enabled.
93 */
94static cputime_t vtime_delta(struct task_struct *tsk)
95{
96 struct thread_info *ti = task_thread_info(tsk);
97 cputime_t delta_stime;
98 __u64 now;
99
100 WARN_ON_ONCE(!irqs_disabled());
101
102 now = ia64_get_itc();
103
104 delta_stime = cycle_to_cputime(ti->ac_stime + (now - ti->ac_stamp));
105 ti->ac_stime = 0;
106 ti->ac_stamp = now;
107
108 return delta_stime;
109}
110
111void vtime_account_system(struct task_struct *tsk)
112{
113 cputime_t delta = vtime_delta(tsk);
114
115 account_system_time(tsk, 0, delta, delta);
116}
117EXPORT_SYMBOL_GPL(vtime_account_system);
118
119void vtime_account_idle(struct task_struct *tsk)
120{
121 account_idle_time(vtime_delta(tsk));
122}
123
124#endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
125
126static irqreturn_t
127timer_interrupt (int irq, void *dev_id)
128{
129 unsigned long new_itm;
130
131 if (cpu_is_offline(smp_processor_id())) {
132 return IRQ_HANDLED;
133 }
134
135 platform_timer_interrupt(irq, dev_id);
136
137 new_itm = local_cpu_data->itm_next;
138
139 if (!time_after(ia64_get_itc(), new_itm))
140 printk(KERN_ERR "Oops: timer tick before it's due (itc=%lx,itm=%lx)\n",
141 ia64_get_itc(), new_itm);
142
143 profile_tick(CPU_PROFILING);
144
145 while (1) {
146 update_process_times(user_mode(get_irq_regs()));
147
148 new_itm += local_cpu_data->itm_delta;
149
150 if (smp_processor_id() == time_keeper_id)
151 xtime_update(1);
152
153 local_cpu_data->itm_next = new_itm;
154
155 if (time_after(new_itm, ia64_get_itc()))
156 break;
157
158 /*
159 * Allow IPIs to interrupt the timer loop.
160 */
161 local_irq_enable();
162 local_irq_disable();
163 }
164
165 do {
166 /*
167 * If we're too close to the next clock tick for
168 * comfort, we increase the safety margin by
169 * intentionally dropping the next tick(s). We do NOT
170 * update itm.next because that would force us to call
171 * xtime_update() which in turn would let our clock run
172 * too fast (with the potentially devastating effect
173 * of losing monotony of time).
174 */
175 while (!time_after(new_itm, ia64_get_itc() + local_cpu_data->itm_delta/2))
176 new_itm += local_cpu_data->itm_delta;
177 ia64_set_itm(new_itm);
178 /* double check, in case we got hit by a (slow) PMI: */
179 } while (time_after_eq(ia64_get_itc(), new_itm));
180 return IRQ_HANDLED;
181}
182
183/*
184 * Encapsulate access to the itm structure for SMP.
185 */
186void
187ia64_cpu_local_tick (void)
188{
189 int cpu = smp_processor_id();
190 unsigned long shift = 0, delta;
191
192 /* arrange for the cycle counter to generate a timer interrupt: */
193 ia64_set_itv(IA64_TIMER_VECTOR);
194
195 delta = local_cpu_data->itm_delta;
196 /*
197 * Stagger the timer tick for each CPU so they don't occur all at (almost) the
198 * same time:
199 */
200 if (cpu) {
201 unsigned long hi = 1UL << ia64_fls(cpu);
202 shift = (2*(cpu - hi) + 1) * delta/hi/2;
203 }
204 local_cpu_data->itm_next = ia64_get_itc() + delta + shift;
205 ia64_set_itm(local_cpu_data->itm_next);
206}
207
208static int nojitter;
209
210static int __init nojitter_setup(char *str)
211{
212 nojitter = 1;
213 printk("Jitter checking for ITC timers disabled\n");
214 return 1;
215}
216
217__setup("nojitter", nojitter_setup);
218
219
220void ia64_init_itm(void)
221{
222 unsigned long platform_base_freq, itc_freq;
223 struct pal_freq_ratio itc_ratio, proc_ratio;
224 long status, platform_base_drift, itc_drift;
225
226 /*
227 * According to SAL v2.6, we need to use a SAL call to determine the platform base
228 * frequency and then a PAL call to determine the frequency ratio between the ITC
229 * and the base frequency.
230 */
231 status = ia64_sal_freq_base(SAL_FREQ_BASE_PLATFORM,
232 &platform_base_freq, &platform_base_drift);
233 if (status != 0) {
234 printk(KERN_ERR "SAL_FREQ_BASE_PLATFORM failed: %s\n", ia64_sal_strerror(status));
235 } else {
236 status = ia64_pal_freq_ratios(&proc_ratio, NULL, &itc_ratio);
237 if (status != 0)
238 printk(KERN_ERR "PAL_FREQ_RATIOS failed with status=%ld\n", status);
239 }
240 if (status != 0) {
241 /* invent "random" values */
242 printk(KERN_ERR
243 "SAL/PAL failed to obtain frequency info---inventing reasonable values\n");
244 platform_base_freq = 100000000;
245 platform_base_drift = -1; /* no drift info */
246 itc_ratio.num = 3;
247 itc_ratio.den = 1;
248 }
249 if (platform_base_freq < 40000000) {
250 printk(KERN_ERR "Platform base frequency %lu bogus---resetting to 75MHz!\n",
251 platform_base_freq);
252 platform_base_freq = 75000000;
253 platform_base_drift = -1;
254 }
255 if (!proc_ratio.den)
256 proc_ratio.den = 1; /* avoid division by zero */
257 if (!itc_ratio.den)
258 itc_ratio.den = 1; /* avoid division by zero */
259
260 itc_freq = (platform_base_freq*itc_ratio.num)/itc_ratio.den;
261
262 local_cpu_data->itm_delta = (itc_freq + HZ/2) / HZ;
263 printk(KERN_DEBUG "CPU %d: base freq=%lu.%03luMHz, ITC ratio=%u/%u, "
264 "ITC freq=%lu.%03luMHz", smp_processor_id(),
265 platform_base_freq / 1000000, (platform_base_freq / 1000) % 1000,
266 itc_ratio.num, itc_ratio.den, itc_freq / 1000000, (itc_freq / 1000) % 1000);
267
268 if (platform_base_drift != -1) {
269 itc_drift = platform_base_drift*itc_ratio.num/itc_ratio.den;
270 printk("+/-%ldppm\n", itc_drift);
271 } else {
272 itc_drift = -1;
273 printk("\n");
274 }
275
276 local_cpu_data->proc_freq = (platform_base_freq*proc_ratio.num)/proc_ratio.den;
277 local_cpu_data->itc_freq = itc_freq;
278 local_cpu_data->cyc_per_usec = (itc_freq + USEC_PER_SEC/2) / USEC_PER_SEC;
279 local_cpu_data->nsec_per_cyc = ((NSEC_PER_SEC<<IA64_NSEC_PER_CYC_SHIFT)
280 + itc_freq/2)/itc_freq;
281
282 if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT)) {
283#ifdef CONFIG_SMP
284 /* On IA64 in an SMP configuration ITCs are never accurately synchronized.
285 * Jitter compensation requires a cmpxchg which may limit
286 * the scalability of the syscalls for retrieving time.
287 * The ITC synchronization is usually successful to within a few
288 * ITC ticks but this is not a sure thing. If you need to improve
289 * timer performance in SMP situations then boot the kernel with the
290 * "nojitter" option. However, doing so may result in time fluctuating (maybe
291 * even going backward) if the ITC offsets between the individual CPUs
292 * are too large.
293 */
294 if (!nojitter)
295 itc_jitter_data.itc_jitter = 1;
296#endif
297 } else
298 /*
299 * ITC is drifty and we have not synchronized the ITCs in smpboot.c.
300 * ITC values may fluctuate significantly between processors.
301 * Clock should not be used for hrtimers. Mark itc as only
302 * useful for boot and testing.
303 *
304 * Note that jitter compensation is off! There is no point of
305 * synchronizing ITCs since they may be large differentials
306 * that change over time.
307 *
308 * The only way to fix this would be to repeatedly sync the
309 * ITCs. Until that time we have to avoid ITC.
310 */
311 clocksource_itc.rating = 50;
312
313 /* avoid softlock up message when cpu is unplug and plugged again. */
314 touch_softlockup_watchdog();
315
316 /* Setup the CPU local timer tick */
317 ia64_cpu_local_tick();
318
319 if (!itc_clocksource) {
320 clocksource_register_hz(&clocksource_itc,
321 local_cpu_data->itc_freq);
322 itc_clocksource = &clocksource_itc;
323 }
324}
325
326static cycle_t itc_get_cycles(struct clocksource *cs)
327{
328 unsigned long lcycle, now, ret;
329
330 if (!itc_jitter_data.itc_jitter)
331 return get_cycles();
332
333 lcycle = itc_jitter_data.itc_lastcycle;
334 now = get_cycles();
335 if (lcycle && time_after(lcycle, now))
336 return lcycle;
337
338 /*
339 * Keep track of the last timer value returned.
340 * In an SMP environment, you could lose out in contention of
341 * cmpxchg. If so, your cmpxchg returns new value which the
342 * winner of contention updated to. Use the new value instead.
343 */
344 ret = cmpxchg(&itc_jitter_data.itc_lastcycle, lcycle, now);
345 if (unlikely(ret != lcycle))
346 return ret;
347
348 return now;
349}
350
351
352static struct irqaction timer_irqaction = {
353 .handler = timer_interrupt,
354 .flags = IRQF_IRQPOLL,
355 .name = "timer"
356};
357
358void read_persistent_clock(struct timespec *ts)
359{
360 efi_gettimeofday(ts);
361}
362
363void __init
364time_init (void)
365{
366 register_percpu_irq(IA64_TIMER_VECTOR, &timer_irqaction);
367 ia64_init_itm();
368}
369
370/*
371 * Generic udelay assumes that if preemption is allowed and the thread
372 * migrates to another CPU, that the ITC values are synchronized across
373 * all CPUs.
374 */
375static void
376ia64_itc_udelay (unsigned long usecs)
377{
378 unsigned long start = ia64_get_itc();
379 unsigned long end = start + usecs*local_cpu_data->cyc_per_usec;
380
381 while (time_before(ia64_get_itc(), end))
382 cpu_relax();
383}
384
385void (*ia64_udelay)(unsigned long usecs) = &ia64_itc_udelay;
386
387void
388udelay (unsigned long usecs)
389{
390 (*ia64_udelay)(usecs);
391}
392EXPORT_SYMBOL(udelay);
393
394/* IA64 doesn't cache the timezone */
395void update_vsyscall_tz(void)
396{
397}
398
399void update_vsyscall_old(struct timespec *wall, struct timespec *wtm,
400 struct clocksource *c, u32 mult, cycle_t cycle_last)
401{
402 write_seqcount_begin(&fsyscall_gtod_data.seq);
403
404 /* copy fsyscall clock data */
405 fsyscall_gtod_data.clk_mask = c->mask;
406 fsyscall_gtod_data.clk_mult = mult;
407 fsyscall_gtod_data.clk_shift = c->shift;
408 fsyscall_gtod_data.clk_fsys_mmio = c->archdata.fsys_mmio;
409 fsyscall_gtod_data.clk_cycle_last = cycle_last;
410
411 /* copy kernel time structures */
412 fsyscall_gtod_data.wall_time.tv_sec = wall->tv_sec;
413 fsyscall_gtod_data.wall_time.tv_nsec = wall->tv_nsec;
414 fsyscall_gtod_data.monotonic_time.tv_sec = wtm->tv_sec
415 + wall->tv_sec;
416 fsyscall_gtod_data.monotonic_time.tv_nsec = wtm->tv_nsec
417 + wall->tv_nsec;
418
419 /* normalize */
420 while (fsyscall_gtod_data.monotonic_time.tv_nsec >= NSEC_PER_SEC) {
421 fsyscall_gtod_data.monotonic_time.tv_nsec -= NSEC_PER_SEC;
422 fsyscall_gtod_data.monotonic_time.tv_sec++;
423 }
424
425 write_seqcount_end(&fsyscall_gtod_data.seq);
426}
427