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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/arch/ia64/kernel/time.c
4 *
5 * Copyright (C) 1998-2003 Hewlett-Packard Co
6 * Stephane Eranian <eranian@hpl.hp.com>
7 * David Mosberger <davidm@hpl.hp.com>
8 * Copyright (C) 1999 Don Dugger <don.dugger@intel.com>
9 * Copyright (C) 1999-2000 VA Linux Systems
10 * Copyright (C) 1999-2000 Walt Drummond <drummond@valinux.com>
11 */
12
13#include <linux/cpu.h>
14#include <linux/init.h>
15#include <linux/kernel.h>
16#include <linux/module.h>
17#include <linux/profile.h>
18#include <linux/sched.h>
19#include <linux/time.h>
20#include <linux/nmi.h>
21#include <linux/interrupt.h>
22#include <linux/efi.h>
23#include <linux/timex.h>
24#include <linux/timekeeper_internal.h>
25#include <linux/platform_device.h>
26#include <linux/sched/cputime.h>
27
28#include <asm/delay.h>
29#include <asm/efi.h>
30#include <asm/hw_irq.h>
31#include <asm/ptrace.h>
32#include <asm/sal.h>
33#include <asm/sections.h>
34
35#include "fsyscall_gtod_data.h"
36#include "irq.h"
37
38static u64 itc_get_cycles(struct clocksource *cs);
39
40struct fsyscall_gtod_data_t fsyscall_gtod_data;
41
42struct itc_jitter_data_t itc_jitter_data;
43
44volatile int time_keeper_id = 0; /* smp_processor_id() of time-keeper */
45
46#ifdef CONFIG_IA64_DEBUG_IRQ
47
48unsigned long last_cli_ip;
49EXPORT_SYMBOL(last_cli_ip);
50
51#endif
52
53static struct clocksource clocksource_itc = {
54 .name = "itc",
55 .rating = 350,
56 .read = itc_get_cycles,
57 .mask = CLOCKSOURCE_MASK(64),
58 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
59};
60static struct clocksource *itc_clocksource;
61
62#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
63
64#include <linux/kernel_stat.h>
65
66extern u64 cycle_to_nsec(u64 cyc);
67
68void vtime_flush(struct task_struct *tsk)
69{
70 struct thread_info *ti = task_thread_info(tsk);
71 u64 delta;
72
73 if (ti->utime)
74 account_user_time(tsk, cycle_to_nsec(ti->utime));
75
76 if (ti->gtime)
77 account_guest_time(tsk, cycle_to_nsec(ti->gtime));
78
79 if (ti->idle_time)
80 account_idle_time(cycle_to_nsec(ti->idle_time));
81
82 if (ti->stime) {
83 delta = cycle_to_nsec(ti->stime);
84 account_system_index_time(tsk, delta, CPUTIME_SYSTEM);
85 }
86
87 if (ti->hardirq_time) {
88 delta = cycle_to_nsec(ti->hardirq_time);
89 account_system_index_time(tsk, delta, CPUTIME_IRQ);
90 }
91
92 if (ti->softirq_time) {
93 delta = cycle_to_nsec(ti->softirq_time);
94 account_system_index_time(tsk, delta, CPUTIME_SOFTIRQ);
95 }
96
97 ti->utime = 0;
98 ti->gtime = 0;
99 ti->idle_time = 0;
100 ti->stime = 0;
101 ti->hardirq_time = 0;
102 ti->softirq_time = 0;
103}
104
105/*
106 * Called from the context switch with interrupts disabled, to charge all
107 * accumulated times to the current process, and to prepare accounting on
108 * the next process.
109 */
110void arch_vtime_task_switch(struct task_struct *prev)
111{
112 struct thread_info *pi = task_thread_info(prev);
113 struct thread_info *ni = task_thread_info(current);
114
115 ni->ac_stamp = pi->ac_stamp;
116 ni->ac_stime = ni->ac_utime = 0;
117}
118
119/*
120 * Account time for a transition between system, hard irq or soft irq state.
121 * Note that this function is called with interrupts enabled.
122 */
123static __u64 vtime_delta(struct task_struct *tsk)
124{
125 struct thread_info *ti = task_thread_info(tsk);
126 __u64 now, delta_stime;
127
128 WARN_ON_ONCE(!irqs_disabled());
129
130 now = ia64_get_itc();
131 delta_stime = now - ti->ac_stamp;
132 ti->ac_stamp = now;
133
134 return delta_stime;
135}
136
137void vtime_account_kernel(struct task_struct *tsk)
138{
139 struct thread_info *ti = task_thread_info(tsk);
140 __u64 stime = vtime_delta(tsk);
141
142 if (tsk->flags & PF_VCPU)
143 ti->gtime += stime;
144 else
145 ti->stime += stime;
146}
147EXPORT_SYMBOL_GPL(vtime_account_kernel);
148
149void vtime_account_idle(struct task_struct *tsk)
150{
151 struct thread_info *ti = task_thread_info(tsk);
152
153 ti->idle_time += vtime_delta(tsk);
154}
155
156void vtime_account_softirq(struct task_struct *tsk)
157{
158 struct thread_info *ti = task_thread_info(tsk);
159
160 ti->softirq_time += vtime_delta(tsk);
161}
162
163void vtime_account_hardirq(struct task_struct *tsk)
164{
165 struct thread_info *ti = task_thread_info(tsk);
166
167 ti->hardirq_time += vtime_delta(tsk);
168}
169
170#endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
171
172static irqreturn_t
173timer_interrupt (int irq, void *dev_id)
174{
175 unsigned long new_itm;
176
177 if (cpu_is_offline(smp_processor_id())) {
178 return IRQ_HANDLED;
179 }
180
181 new_itm = local_cpu_data->itm_next;
182
183 if (!time_after(ia64_get_itc(), new_itm))
184 printk(KERN_ERR "Oops: timer tick before it's due (itc=%lx,itm=%lx)\n",
185 ia64_get_itc(), new_itm);
186
187 while (1) {
188 new_itm += local_cpu_data->itm_delta;
189
190 legacy_timer_tick(smp_processor_id() == time_keeper_id);
191
192 local_cpu_data->itm_next = new_itm;
193
194 if (time_after(new_itm, ia64_get_itc()))
195 break;
196
197 /*
198 * Allow IPIs to interrupt the timer loop.
199 */
200 local_irq_enable();
201 local_irq_disable();
202 }
203
204 do {
205 /*
206 * If we're too close to the next clock tick for
207 * comfort, we increase the safety margin by
208 * intentionally dropping the next tick(s). We do NOT
209 * update itm.next because that would force us to call
210 * xtime_update() which in turn would let our clock run
211 * too fast (with the potentially devastating effect
212 * of losing monotony of time).
213 */
214 while (!time_after(new_itm, ia64_get_itc() + local_cpu_data->itm_delta/2))
215 new_itm += local_cpu_data->itm_delta;
216 ia64_set_itm(new_itm);
217 /* double check, in case we got hit by a (slow) PMI: */
218 } while (time_after_eq(ia64_get_itc(), new_itm));
219 return IRQ_HANDLED;
220}
221
222/*
223 * Encapsulate access to the itm structure for SMP.
224 */
225void
226ia64_cpu_local_tick (void)
227{
228 int cpu = smp_processor_id();
229 unsigned long shift = 0, delta;
230
231 /* arrange for the cycle counter to generate a timer interrupt: */
232 ia64_set_itv(IA64_TIMER_VECTOR);
233
234 delta = local_cpu_data->itm_delta;
235 /*
236 * Stagger the timer tick for each CPU so they don't occur all at (almost) the
237 * same time:
238 */
239 if (cpu) {
240 unsigned long hi = 1UL << ia64_fls(cpu);
241 shift = (2*(cpu - hi) + 1) * delta/hi/2;
242 }
243 local_cpu_data->itm_next = ia64_get_itc() + delta + shift;
244 ia64_set_itm(local_cpu_data->itm_next);
245}
246
247static int nojitter;
248
249static int __init nojitter_setup(char *str)
250{
251 nojitter = 1;
252 printk("Jitter checking for ITC timers disabled\n");
253 return 1;
254}
255
256__setup("nojitter", nojitter_setup);
257
258
259void ia64_init_itm(void)
260{
261 unsigned long platform_base_freq, itc_freq;
262 struct pal_freq_ratio itc_ratio, proc_ratio;
263 long status, platform_base_drift, itc_drift;
264
265 /*
266 * According to SAL v2.6, we need to use a SAL call to determine the platform base
267 * frequency and then a PAL call to determine the frequency ratio between the ITC
268 * and the base frequency.
269 */
270 status = ia64_sal_freq_base(SAL_FREQ_BASE_PLATFORM,
271 &platform_base_freq, &platform_base_drift);
272 if (status != 0) {
273 printk(KERN_ERR "SAL_FREQ_BASE_PLATFORM failed: %s\n", ia64_sal_strerror(status));
274 } else {
275 status = ia64_pal_freq_ratios(&proc_ratio, NULL, &itc_ratio);
276 if (status != 0)
277 printk(KERN_ERR "PAL_FREQ_RATIOS failed with status=%ld\n", status);
278 }
279 if (status != 0) {
280 /* invent "random" values */
281 printk(KERN_ERR
282 "SAL/PAL failed to obtain frequency info---inventing reasonable values\n");
283 platform_base_freq = 100000000;
284 platform_base_drift = -1; /* no drift info */
285 itc_ratio.num = 3;
286 itc_ratio.den = 1;
287 }
288 if (platform_base_freq < 40000000) {
289 printk(KERN_ERR "Platform base frequency %lu bogus---resetting to 75MHz!\n",
290 platform_base_freq);
291 platform_base_freq = 75000000;
292 platform_base_drift = -1;
293 }
294 if (!proc_ratio.den)
295 proc_ratio.den = 1; /* avoid division by zero */
296 if (!itc_ratio.den)
297 itc_ratio.den = 1; /* avoid division by zero */
298
299 itc_freq = (platform_base_freq*itc_ratio.num)/itc_ratio.den;
300
301 local_cpu_data->itm_delta = (itc_freq + HZ/2) / HZ;
302 printk(KERN_DEBUG "CPU %d: base freq=%lu.%03luMHz, ITC ratio=%u/%u, "
303 "ITC freq=%lu.%03luMHz", smp_processor_id(),
304 platform_base_freq / 1000000, (platform_base_freq / 1000) % 1000,
305 itc_ratio.num, itc_ratio.den, itc_freq / 1000000, (itc_freq / 1000) % 1000);
306
307 if (platform_base_drift != -1) {
308 itc_drift = platform_base_drift*itc_ratio.num/itc_ratio.den;
309 printk("+/-%ldppm\n", itc_drift);
310 } else {
311 itc_drift = -1;
312 printk("\n");
313 }
314
315 local_cpu_data->proc_freq = (platform_base_freq*proc_ratio.num)/proc_ratio.den;
316 local_cpu_data->itc_freq = itc_freq;
317 local_cpu_data->cyc_per_usec = (itc_freq + USEC_PER_SEC/2) / USEC_PER_SEC;
318 local_cpu_data->nsec_per_cyc = ((NSEC_PER_SEC<<IA64_NSEC_PER_CYC_SHIFT)
319 + itc_freq/2)/itc_freq;
320
321 if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT)) {
322#ifdef CONFIG_SMP
323 /* On IA64 in an SMP configuration ITCs are never accurately synchronized.
324 * Jitter compensation requires a cmpxchg which may limit
325 * the scalability of the syscalls for retrieving time.
326 * The ITC synchronization is usually successful to within a few
327 * ITC ticks but this is not a sure thing. If you need to improve
328 * timer performance in SMP situations then boot the kernel with the
329 * "nojitter" option. However, doing so may result in time fluctuating (maybe
330 * even going backward) if the ITC offsets between the individual CPUs
331 * are too large.
332 */
333 if (!nojitter)
334 itc_jitter_data.itc_jitter = 1;
335#endif
336 } else
337 /*
338 * ITC is drifty and we have not synchronized the ITCs in smpboot.c.
339 * ITC values may fluctuate significantly between processors.
340 * Clock should not be used for hrtimers. Mark itc as only
341 * useful for boot and testing.
342 *
343 * Note that jitter compensation is off! There is no point of
344 * synchronizing ITCs since they may be large differentials
345 * that change over time.
346 *
347 * The only way to fix this would be to repeatedly sync the
348 * ITCs. Until that time we have to avoid ITC.
349 */
350 clocksource_itc.rating = 50;
351
352 /* avoid softlock up message when cpu is unplug and plugged again. */
353 touch_softlockup_watchdog();
354
355 /* Setup the CPU local timer tick */
356 ia64_cpu_local_tick();
357
358 if (!itc_clocksource) {
359 clocksource_register_hz(&clocksource_itc,
360 local_cpu_data->itc_freq);
361 itc_clocksource = &clocksource_itc;
362 }
363}
364
365static u64 itc_get_cycles(struct clocksource *cs)
366{
367 unsigned long lcycle, now, ret;
368
369 if (!itc_jitter_data.itc_jitter)
370 return get_cycles();
371
372 lcycle = itc_jitter_data.itc_lastcycle;
373 now = get_cycles();
374 if (lcycle && time_after(lcycle, now))
375 return lcycle;
376
377 /*
378 * Keep track of the last timer value returned.
379 * In an SMP environment, you could lose out in contention of
380 * cmpxchg. If so, your cmpxchg returns new value which the
381 * winner of contention updated to. Use the new value instead.
382 */
383 ret = cmpxchg(&itc_jitter_data.itc_lastcycle, lcycle, now);
384 if (unlikely(ret != lcycle))
385 return ret;
386
387 return now;
388}
389
390void read_persistent_clock64(struct timespec64 *ts)
391{
392 efi_gettimeofday(ts);
393}
394
395void __init
396time_init (void)
397{
398 register_percpu_irq(IA64_TIMER_VECTOR, timer_interrupt, IRQF_IRQPOLL,
399 "timer");
400 ia64_init_itm();
401}
402
403/*
404 * Generic udelay assumes that if preemption is allowed and the thread
405 * migrates to another CPU, that the ITC values are synchronized across
406 * all CPUs.
407 */
408static void
409ia64_itc_udelay (unsigned long usecs)
410{
411 unsigned long start = ia64_get_itc();
412 unsigned long end = start + usecs*local_cpu_data->cyc_per_usec;
413
414 while (time_before(ia64_get_itc(), end))
415 cpu_relax();
416}
417
418void (*ia64_udelay)(unsigned long usecs) = &ia64_itc_udelay;
419
420void
421udelay (unsigned long usecs)
422{
423 (*ia64_udelay)(usecs);
424}
425EXPORT_SYMBOL(udelay);
426
427/* IA64 doesn't cache the timezone */
428void update_vsyscall_tz(void)
429{
430}
431
432void update_vsyscall(struct timekeeper *tk)
433{
434 write_seqcount_begin(&fsyscall_gtod_data.seq);
435
436 /* copy vsyscall data */
437 fsyscall_gtod_data.clk_mask = tk->tkr_mono.mask;
438 fsyscall_gtod_data.clk_mult = tk->tkr_mono.mult;
439 fsyscall_gtod_data.clk_shift = tk->tkr_mono.shift;
440 fsyscall_gtod_data.clk_fsys_mmio = tk->tkr_mono.clock->archdata.fsys_mmio;
441 fsyscall_gtod_data.clk_cycle_last = tk->tkr_mono.cycle_last;
442
443 fsyscall_gtod_data.wall_time.sec = tk->xtime_sec;
444 fsyscall_gtod_data.wall_time.snsec = tk->tkr_mono.xtime_nsec;
445
446 fsyscall_gtod_data.monotonic_time.sec = tk->xtime_sec
447 + tk->wall_to_monotonic.tv_sec;
448 fsyscall_gtod_data.monotonic_time.snsec = tk->tkr_mono.xtime_nsec
449 + ((u64)tk->wall_to_monotonic.tv_nsec
450 << tk->tkr_mono.shift);
451
452 /* normalize */
453 while (fsyscall_gtod_data.monotonic_time.snsec >=
454 (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift)) {
455 fsyscall_gtod_data.monotonic_time.snsec -=
456 ((u64)NSEC_PER_SEC) << tk->tkr_mono.shift;
457 fsyscall_gtod_data.monotonic_time.sec++;
458 }
459
460 write_seqcount_end(&fsyscall_gtod_data.seq);
461}
462
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/clocksource.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#include <asm/system.h>
33
34#include "fsyscall_gtod_data.h"
35
36static cycle_t itc_get_cycles(struct clocksource *cs);
37
38struct fsyscall_gtod_data_t fsyscall_gtod_data = {
39 .lock = __SEQLOCK_UNLOCKED(fsyscall_gtod_data.lock),
40};
41
42struct itc_jitter_data_t itc_jitter_data;
43
44volatile int time_keeper_id = 0; /* smp_processor_id() of time-keeper */
45
46#ifdef CONFIG_IA64_DEBUG_IRQ
47
48unsigned long last_cli_ip;
49EXPORT_SYMBOL(last_cli_ip);
50
51#endif
52
53#ifdef CONFIG_PARAVIRT
54/* We need to define a real function for sched_clock, to override the
55 weak default version */
56unsigned long long sched_clock(void)
57{
58 return paravirt_sched_clock();
59}
60#endif
61
62#ifdef CONFIG_PARAVIRT
63static void
64paravirt_clocksource_resume(struct clocksource *cs)
65{
66 if (pv_time_ops.clocksource_resume)
67 pv_time_ops.clocksource_resume();
68}
69#endif
70
71static struct clocksource clocksource_itc = {
72 .name = "itc",
73 .rating = 350,
74 .read = itc_get_cycles,
75 .mask = CLOCKSOURCE_MASK(64),
76 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
77#ifdef CONFIG_PARAVIRT
78 .resume = paravirt_clocksource_resume,
79#endif
80};
81static struct clocksource *itc_clocksource;
82
83#ifdef CONFIG_VIRT_CPU_ACCOUNTING
84
85#include <linux/kernel_stat.h>
86
87extern cputime_t cycle_to_cputime(u64 cyc);
88
89/*
90 * Called from the context switch with interrupts disabled, to charge all
91 * accumulated times to the current process, and to prepare accounting on
92 * the next process.
93 */
94void ia64_account_on_switch(struct task_struct *prev, struct task_struct *next)
95{
96 struct thread_info *pi = task_thread_info(prev);
97 struct thread_info *ni = task_thread_info(next);
98 cputime_t delta_stime, delta_utime;
99 __u64 now;
100
101 now = ia64_get_itc();
102
103 delta_stime = cycle_to_cputime(pi->ac_stime + (now - pi->ac_stamp));
104 if (idle_task(smp_processor_id()) != prev)
105 account_system_time(prev, 0, delta_stime, delta_stime);
106 else
107 account_idle_time(delta_stime);
108
109 if (pi->ac_utime) {
110 delta_utime = cycle_to_cputime(pi->ac_utime);
111 account_user_time(prev, delta_utime, delta_utime);
112 }
113
114 pi->ac_stamp = ni->ac_stamp = now;
115 ni->ac_stime = ni->ac_utime = 0;
116}
117
118/*
119 * Account time for a transition between system, hard irq or soft irq state.
120 * Note that this function is called with interrupts enabled.
121 */
122void account_system_vtime(struct task_struct *tsk)
123{
124 struct thread_info *ti = task_thread_info(tsk);
125 unsigned long flags;
126 cputime_t delta_stime;
127 __u64 now;
128
129 local_irq_save(flags);
130
131 now = ia64_get_itc();
132
133 delta_stime = cycle_to_cputime(ti->ac_stime + (now - ti->ac_stamp));
134 if (irq_count() || idle_task(smp_processor_id()) != tsk)
135 account_system_time(tsk, 0, delta_stime, delta_stime);
136 else
137 account_idle_time(delta_stime);
138 ti->ac_stime = 0;
139
140 ti->ac_stamp = now;
141
142 local_irq_restore(flags);
143}
144EXPORT_SYMBOL_GPL(account_system_vtime);
145
146/*
147 * Called from the timer interrupt handler to charge accumulated user time
148 * to the current process. Must be called with interrupts disabled.
149 */
150void account_process_tick(struct task_struct *p, int user_tick)
151{
152 struct thread_info *ti = task_thread_info(p);
153 cputime_t delta_utime;
154
155 if (ti->ac_utime) {
156 delta_utime = cycle_to_cputime(ti->ac_utime);
157 account_user_time(p, delta_utime, delta_utime);
158 ti->ac_utime = 0;
159 }
160}
161
162#endif /* CONFIG_VIRT_CPU_ACCOUNTING */
163
164static irqreturn_t
165timer_interrupt (int irq, void *dev_id)
166{
167 unsigned long new_itm;
168
169 if (cpu_is_offline(smp_processor_id())) {
170 return IRQ_HANDLED;
171 }
172
173 platform_timer_interrupt(irq, dev_id);
174
175 new_itm = local_cpu_data->itm_next;
176
177 if (!time_after(ia64_get_itc(), new_itm))
178 printk(KERN_ERR "Oops: timer tick before it's due (itc=%lx,itm=%lx)\n",
179 ia64_get_itc(), new_itm);
180
181 profile_tick(CPU_PROFILING);
182
183 if (paravirt_do_steal_accounting(&new_itm))
184 goto skip_process_time_accounting;
185
186 while (1) {
187 update_process_times(user_mode(get_irq_regs()));
188
189 new_itm += local_cpu_data->itm_delta;
190
191 if (smp_processor_id() == time_keeper_id)
192 xtime_update(1);
193
194 local_cpu_data->itm_next = new_itm;
195
196 if (time_after(new_itm, ia64_get_itc()))
197 break;
198
199 /*
200 * Allow IPIs to interrupt the timer loop.
201 */
202 local_irq_enable();
203 local_irq_disable();
204 }
205
206skip_process_time_accounting:
207
208 do {
209 /*
210 * If we're too close to the next clock tick for
211 * comfort, we increase the safety margin by
212 * intentionally dropping the next tick(s). We do NOT
213 * update itm.next because that would force us to call
214 * xtime_update() which in turn would let our clock run
215 * too fast (with the potentially devastating effect
216 * of losing monotony of time).
217 */
218 while (!time_after(new_itm, ia64_get_itc() + local_cpu_data->itm_delta/2))
219 new_itm += local_cpu_data->itm_delta;
220 ia64_set_itm(new_itm);
221 /* double check, in case we got hit by a (slow) PMI: */
222 } while (time_after_eq(ia64_get_itc(), new_itm));
223 return IRQ_HANDLED;
224}
225
226/*
227 * Encapsulate access to the itm structure for SMP.
228 */
229void
230ia64_cpu_local_tick (void)
231{
232 int cpu = smp_processor_id();
233 unsigned long shift = 0, delta;
234
235 /* arrange for the cycle counter to generate a timer interrupt: */
236 ia64_set_itv(IA64_TIMER_VECTOR);
237
238 delta = local_cpu_data->itm_delta;
239 /*
240 * Stagger the timer tick for each CPU so they don't occur all at (almost) the
241 * same time:
242 */
243 if (cpu) {
244 unsigned long hi = 1UL << ia64_fls(cpu);
245 shift = (2*(cpu - hi) + 1) * delta/hi/2;
246 }
247 local_cpu_data->itm_next = ia64_get_itc() + delta + shift;
248 ia64_set_itm(local_cpu_data->itm_next);
249}
250
251static int nojitter;
252
253static int __init nojitter_setup(char *str)
254{
255 nojitter = 1;
256 printk("Jitter checking for ITC timers disabled\n");
257 return 1;
258}
259
260__setup("nojitter", nojitter_setup);
261
262
263void __devinit
264ia64_init_itm (void)
265{
266 unsigned long platform_base_freq, itc_freq;
267 struct pal_freq_ratio itc_ratio, proc_ratio;
268 long status, platform_base_drift, itc_drift;
269
270 /*
271 * According to SAL v2.6, we need to use a SAL call to determine the platform base
272 * frequency and then a PAL call to determine the frequency ratio between the ITC
273 * and the base frequency.
274 */
275 status = ia64_sal_freq_base(SAL_FREQ_BASE_PLATFORM,
276 &platform_base_freq, &platform_base_drift);
277 if (status != 0) {
278 printk(KERN_ERR "SAL_FREQ_BASE_PLATFORM failed: %s\n", ia64_sal_strerror(status));
279 } else {
280 status = ia64_pal_freq_ratios(&proc_ratio, NULL, &itc_ratio);
281 if (status != 0)
282 printk(KERN_ERR "PAL_FREQ_RATIOS failed with status=%ld\n", status);
283 }
284 if (status != 0) {
285 /* invent "random" values */
286 printk(KERN_ERR
287 "SAL/PAL failed to obtain frequency info---inventing reasonable values\n");
288 platform_base_freq = 100000000;
289 platform_base_drift = -1; /* no drift info */
290 itc_ratio.num = 3;
291 itc_ratio.den = 1;
292 }
293 if (platform_base_freq < 40000000) {
294 printk(KERN_ERR "Platform base frequency %lu bogus---resetting to 75MHz!\n",
295 platform_base_freq);
296 platform_base_freq = 75000000;
297 platform_base_drift = -1;
298 }
299 if (!proc_ratio.den)
300 proc_ratio.den = 1; /* avoid division by zero */
301 if (!itc_ratio.den)
302 itc_ratio.den = 1; /* avoid division by zero */
303
304 itc_freq = (platform_base_freq*itc_ratio.num)/itc_ratio.den;
305
306 local_cpu_data->itm_delta = (itc_freq + HZ/2) / HZ;
307 printk(KERN_DEBUG "CPU %d: base freq=%lu.%03luMHz, ITC ratio=%u/%u, "
308 "ITC freq=%lu.%03luMHz", smp_processor_id(),
309 platform_base_freq / 1000000, (platform_base_freq / 1000) % 1000,
310 itc_ratio.num, itc_ratio.den, itc_freq / 1000000, (itc_freq / 1000) % 1000);
311
312 if (platform_base_drift != -1) {
313 itc_drift = platform_base_drift*itc_ratio.num/itc_ratio.den;
314 printk("+/-%ldppm\n", itc_drift);
315 } else {
316 itc_drift = -1;
317 printk("\n");
318 }
319
320 local_cpu_data->proc_freq = (platform_base_freq*proc_ratio.num)/proc_ratio.den;
321 local_cpu_data->itc_freq = itc_freq;
322 local_cpu_data->cyc_per_usec = (itc_freq + USEC_PER_SEC/2) / USEC_PER_SEC;
323 local_cpu_data->nsec_per_cyc = ((NSEC_PER_SEC<<IA64_NSEC_PER_CYC_SHIFT)
324 + itc_freq/2)/itc_freq;
325
326 if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT)) {
327#ifdef CONFIG_SMP
328 /* On IA64 in an SMP configuration ITCs are never accurately synchronized.
329 * Jitter compensation requires a cmpxchg which may limit
330 * the scalability of the syscalls for retrieving time.
331 * The ITC synchronization is usually successful to within a few
332 * ITC ticks but this is not a sure thing. If you need to improve
333 * timer performance in SMP situations then boot the kernel with the
334 * "nojitter" option. However, doing so may result in time fluctuating (maybe
335 * even going backward) if the ITC offsets between the individual CPUs
336 * are too large.
337 */
338 if (!nojitter)
339 itc_jitter_data.itc_jitter = 1;
340#endif
341 } else
342 /*
343 * ITC is drifty and we have not synchronized the ITCs in smpboot.c.
344 * ITC values may fluctuate significantly between processors.
345 * Clock should not be used for hrtimers. Mark itc as only
346 * useful for boot and testing.
347 *
348 * Note that jitter compensation is off! There is no point of
349 * synchronizing ITCs since they may be large differentials
350 * that change over time.
351 *
352 * The only way to fix this would be to repeatedly sync the
353 * ITCs. Until that time we have to avoid ITC.
354 */
355 clocksource_itc.rating = 50;
356
357 paravirt_init_missing_ticks_accounting(smp_processor_id());
358
359 /* avoid softlock up message when cpu is unplug and plugged again. */
360 touch_softlockup_watchdog();
361
362 /* Setup the CPU local timer tick */
363 ia64_cpu_local_tick();
364
365 if (!itc_clocksource) {
366 clocksource_register_hz(&clocksource_itc,
367 local_cpu_data->itc_freq);
368 itc_clocksource = &clocksource_itc;
369 }
370}
371
372static cycle_t itc_get_cycles(struct clocksource *cs)
373{
374 unsigned long lcycle, now, ret;
375
376 if (!itc_jitter_data.itc_jitter)
377 return get_cycles();
378
379 lcycle = itc_jitter_data.itc_lastcycle;
380 now = get_cycles();
381 if (lcycle && time_after(lcycle, now))
382 return lcycle;
383
384 /*
385 * Keep track of the last timer value returned.
386 * In an SMP environment, you could lose out in contention of
387 * cmpxchg. If so, your cmpxchg returns new value which the
388 * winner of contention updated to. Use the new value instead.
389 */
390 ret = cmpxchg(&itc_jitter_data.itc_lastcycle, lcycle, now);
391 if (unlikely(ret != lcycle))
392 return ret;
393
394 return now;
395}
396
397
398static struct irqaction timer_irqaction = {
399 .handler = timer_interrupt,
400 .flags = IRQF_DISABLED | IRQF_IRQPOLL,
401 .name = "timer"
402};
403
404static struct platform_device rtc_efi_dev = {
405 .name = "rtc-efi",
406 .id = -1,
407};
408
409static int __init rtc_init(void)
410{
411 if (platform_device_register(&rtc_efi_dev) < 0)
412 printk(KERN_ERR "unable to register rtc device...\n");
413
414 /* not necessarily an error */
415 return 0;
416}
417module_init(rtc_init);
418
419void read_persistent_clock(struct timespec *ts)
420{
421 efi_gettimeofday(ts);
422}
423
424void __init
425time_init (void)
426{
427 register_percpu_irq(IA64_TIMER_VECTOR, &timer_irqaction);
428 ia64_init_itm();
429}
430
431/*
432 * Generic udelay assumes that if preemption is allowed and the thread
433 * migrates to another CPU, that the ITC values are synchronized across
434 * all CPUs.
435 */
436static void
437ia64_itc_udelay (unsigned long usecs)
438{
439 unsigned long start = ia64_get_itc();
440 unsigned long end = start + usecs*local_cpu_data->cyc_per_usec;
441
442 while (time_before(ia64_get_itc(), end))
443 cpu_relax();
444}
445
446void (*ia64_udelay)(unsigned long usecs) = &ia64_itc_udelay;
447
448void
449udelay (unsigned long usecs)
450{
451 (*ia64_udelay)(usecs);
452}
453EXPORT_SYMBOL(udelay);
454
455/* IA64 doesn't cache the timezone */
456void update_vsyscall_tz(void)
457{
458}
459
460void update_vsyscall(struct timespec *wall, struct timespec *wtm,
461 struct clocksource *c, u32 mult)
462{
463 unsigned long flags;
464
465 write_seqlock_irqsave(&fsyscall_gtod_data.lock, flags);
466
467 /* copy fsyscall clock data */
468 fsyscall_gtod_data.clk_mask = c->mask;
469 fsyscall_gtod_data.clk_mult = mult;
470 fsyscall_gtod_data.clk_shift = c->shift;
471 fsyscall_gtod_data.clk_fsys_mmio = c->archdata.fsys_mmio;
472 fsyscall_gtod_data.clk_cycle_last = c->cycle_last;
473
474 /* copy kernel time structures */
475 fsyscall_gtod_data.wall_time.tv_sec = wall->tv_sec;
476 fsyscall_gtod_data.wall_time.tv_nsec = wall->tv_nsec;
477 fsyscall_gtod_data.monotonic_time.tv_sec = wtm->tv_sec
478 + wall->tv_sec;
479 fsyscall_gtod_data.monotonic_time.tv_nsec = wtm->tv_nsec
480 + wall->tv_nsec;
481
482 /* normalize */
483 while (fsyscall_gtod_data.monotonic_time.tv_nsec >= NSEC_PER_SEC) {
484 fsyscall_gtod_data.monotonic_time.tv_nsec -= NSEC_PER_SEC;
485 fsyscall_gtod_data.monotonic_time.tv_sec++;
486 }
487
488 write_sequnlock_irqrestore(&fsyscall_gtod_data.lock, flags);
489}
490