~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/arch/s390/kernel/time.c

Version: ~ [ linux-5.9 ] ~ [ linux-5.8.14 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.70 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.150 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.200 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.238 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.238 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.85 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  *    Time of day based timer functions.
  3  *
  4  *  S390 version
  5  *    Copyright IBM Corp. 1999, 2008
  6  *    Author(s): Hartmut Penner (hp@de.ibm.com),
  7  *               Martin Schwidefsky (schwidefsky@de.ibm.com),
  8  *               Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
  9  *
 10  *  Derived from "arch/i386/kernel/time.c"
 11  *    Copyright (C) 1991, 1992, 1995  Linus Torvalds
 12  */
 13 
 14 #define KMSG_COMPONENT "time"
 15 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
 16 
 17 #include <linux/kernel_stat.h>
 18 #include <linux/errno.h>
 19 #include <linux/module.h>
 20 #include <linux/sched.h>
 21 #include <linux/kernel.h>
 22 #include <linux/param.h>
 23 #include <linux/string.h>
 24 #include <linux/mm.h>
 25 #include <linux/interrupt.h>
 26 #include <linux/cpu.h>
 27 #include <linux/stop_machine.h>
 28 #include <linux/time.h>
 29 #include <linux/device.h>
 30 #include <linux/delay.h>
 31 #include <linux/init.h>
 32 #include <linux/smp.h>
 33 #include <linux/types.h>
 34 #include <linux/profile.h>
 35 #include <linux/timex.h>
 36 #include <linux/notifier.h>
 37 #include <linux/timekeeper_internal.h>
 38 #include <linux/clockchips.h>
 39 #include <linux/gfp.h>
 40 #include <linux/kprobes.h>
 41 #include <asm/uaccess.h>
 42 #include <asm/delay.h>
 43 #include <asm/div64.h>
 44 #include <asm/vdso.h>
 45 #include <asm/irq.h>
 46 #include <asm/irq_regs.h>
 47 #include <asm/vtimer.h>
 48 #include <asm/etr.h>
 49 #include <asm/cio.h>
 50 #include "entry.h"
 51 
 52 /* change this if you have some constant time drift */
 53 #define USECS_PER_JIFFY     ((unsigned long) 1000000/HZ)
 54 #define CLK_TICKS_PER_JIFFY ((unsigned long) USECS_PER_JIFFY << 12)
 55 
 56 u64 sched_clock_base_cc = -1;   /* Force to data section. */
 57 EXPORT_SYMBOL_GPL(sched_clock_base_cc);
 58 
 59 static DEFINE_PER_CPU(struct clock_event_device, comparators);
 60 
 61 /*
 62  * Scheduler clock - returns current time in nanosec units.
 63  */
 64 unsigned long long notrace sched_clock(void)
 65 {
 66         return tod_to_ns(get_tod_clock_monotonic());
 67 }
 68 NOKPROBE_SYMBOL(sched_clock);
 69 
 70 /*
 71  * Monotonic_clock - returns # of nanoseconds passed since time_init()
 72  */
 73 unsigned long long monotonic_clock(void)
 74 {
 75         return sched_clock();
 76 }
 77 EXPORT_SYMBOL(monotonic_clock);
 78 
 79 void tod_to_timeval(__u64 todval, struct timespec *xt)
 80 {
 81         unsigned long long sec;
 82 
 83         sec = todval >> 12;
 84         do_div(sec, 1000000);
 85         xt->tv_sec = sec;
 86         todval -= (sec * 1000000) << 12;
 87         xt->tv_nsec = ((todval * 1000) >> 12);
 88 }
 89 EXPORT_SYMBOL(tod_to_timeval);
 90 
 91 void clock_comparator_work(void)
 92 {
 93         struct clock_event_device *cd;
 94 
 95         S390_lowcore.clock_comparator = -1ULL;
 96         cd = this_cpu_ptr(&comparators);
 97         cd->event_handler(cd);
 98 }
 99 
100 /*
101  * Fixup the clock comparator.
102  */
103 static void fixup_clock_comparator(unsigned long long delta)
104 {
105         /* If nobody is waiting there's nothing to fix. */
106         if (S390_lowcore.clock_comparator == -1ULL)
107                 return;
108         S390_lowcore.clock_comparator += delta;
109         set_clock_comparator(S390_lowcore.clock_comparator);
110 }
111 
112 static int s390_next_event(unsigned long delta,
113                            struct clock_event_device *evt)
114 {
115         S390_lowcore.clock_comparator = get_tod_clock() + delta;
116         set_clock_comparator(S390_lowcore.clock_comparator);
117         return 0;
118 }
119 
120 static void s390_set_mode(enum clock_event_mode mode,
121                           struct clock_event_device *evt)
122 {
123 }
124 
125 /*
126  * Set up lowcore and control register of the current cpu to
127  * enable TOD clock and clock comparator interrupts.
128  */
129 void init_cpu_timer(void)
130 {
131         struct clock_event_device *cd;
132         int cpu;
133 
134         S390_lowcore.clock_comparator = -1ULL;
135         set_clock_comparator(S390_lowcore.clock_comparator);
136 
137         cpu = smp_processor_id();
138         cd = &per_cpu(comparators, cpu);
139         cd->name                = "comparator";
140         cd->features            = CLOCK_EVT_FEAT_ONESHOT;
141         cd->mult                = 16777;
142         cd->shift               = 12;
143         cd->min_delta_ns        = 1;
144         cd->max_delta_ns        = LONG_MAX;
145         cd->rating              = 400;
146         cd->cpumask             = cpumask_of(cpu);
147         cd->set_next_event      = s390_next_event;
148         cd->set_mode            = s390_set_mode;
149 
150         clockevents_register_device(cd);
151 
152         /* Enable clock comparator timer interrupt. */
153         __ctl_set_bit(0,11);
154 
155         /* Always allow the timing alert external interrupt. */
156         __ctl_set_bit(0, 4);
157 }
158 
159 static void clock_comparator_interrupt(struct ext_code ext_code,
160                                        unsigned int param32,
161                                        unsigned long param64)
162 {
163         inc_irq_stat(IRQEXT_CLK);
164         if (S390_lowcore.clock_comparator == -1ULL)
165                 set_clock_comparator(S390_lowcore.clock_comparator);
166 }
167 
168 static void etr_timing_alert(struct etr_irq_parm *);
169 static void stp_timing_alert(struct stp_irq_parm *);
170 
171 static void timing_alert_interrupt(struct ext_code ext_code,
172                                    unsigned int param32, unsigned long param64)
173 {
174         inc_irq_stat(IRQEXT_TLA);
175         if (param32 & 0x00c40000)
176                 etr_timing_alert((struct etr_irq_parm *) &param32);
177         if (param32 & 0x00038000)
178                 stp_timing_alert((struct stp_irq_parm *) &param32);
179 }
180 
181 static void etr_reset(void);
182 static void stp_reset(void);
183 
184 void read_persistent_clock(struct timespec *ts)
185 {
186         tod_to_timeval(get_tod_clock() - TOD_UNIX_EPOCH, ts);
187 }
188 
189 void read_boot_clock(struct timespec *ts)
190 {
191         tod_to_timeval(sched_clock_base_cc - TOD_UNIX_EPOCH, ts);
192 }
193 
194 static cycle_t read_tod_clock(struct clocksource *cs)
195 {
196         return get_tod_clock();
197 }
198 
199 static struct clocksource clocksource_tod = {
200         .name           = "tod",
201         .rating         = 400,
202         .read           = read_tod_clock,
203         .mask           = -1ULL,
204         .mult           = 1000,
205         .shift          = 12,
206         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
207 };
208 
209 struct clocksource * __init clocksource_default_clock(void)
210 {
211         return &clocksource_tod;
212 }
213 
214 void update_vsyscall(struct timekeeper *tk)
215 {
216         u64 nsecps;
217 
218         if (tk->tkr.clock != &clocksource_tod)
219                 return;
220 
221         /* Make userspace gettimeofday spin until we're done. */
222         ++vdso_data->tb_update_count;
223         smp_wmb();
224         vdso_data->xtime_tod_stamp = tk->tkr.cycle_last;
225         vdso_data->xtime_clock_sec = tk->xtime_sec;
226         vdso_data->xtime_clock_nsec = tk->tkr.xtime_nsec;
227         vdso_data->wtom_clock_sec =
228                 tk->xtime_sec + tk->wall_to_monotonic.tv_sec;
229         vdso_data->wtom_clock_nsec = tk->tkr.xtime_nsec +
230                 + ((u64) tk->wall_to_monotonic.tv_nsec << tk->tkr.shift);
231         nsecps = (u64) NSEC_PER_SEC << tk->tkr.shift;
232         while (vdso_data->wtom_clock_nsec >= nsecps) {
233                 vdso_data->wtom_clock_nsec -= nsecps;
234                 vdso_data->wtom_clock_sec++;
235         }
236 
237         vdso_data->xtime_coarse_sec = tk->xtime_sec;
238         vdso_data->xtime_coarse_nsec =
239                 (long)(tk->tkr.xtime_nsec >> tk->tkr.shift);
240         vdso_data->wtom_coarse_sec =
241                 vdso_data->xtime_coarse_sec + tk->wall_to_monotonic.tv_sec;
242         vdso_data->wtom_coarse_nsec =
243                 vdso_data->xtime_coarse_nsec + tk->wall_to_monotonic.tv_nsec;
244         while (vdso_data->wtom_coarse_nsec >= NSEC_PER_SEC) {
245                 vdso_data->wtom_coarse_nsec -= NSEC_PER_SEC;
246                 vdso_data->wtom_coarse_sec++;
247         }
248 
249         vdso_data->tk_mult = tk->tkr.mult;
250         vdso_data->tk_shift = tk->tkr.shift;
251         smp_wmb();
252         ++vdso_data->tb_update_count;
253 }
254 
255 extern struct timezone sys_tz;
256 
257 void update_vsyscall_tz(void)
258 {
259         /* Make userspace gettimeofday spin until we're done. */
260         ++vdso_data->tb_update_count;
261         smp_wmb();
262         vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
263         vdso_data->tz_dsttime = sys_tz.tz_dsttime;
264         smp_wmb();
265         ++vdso_data->tb_update_count;
266 }
267 
268 /*
269  * Initialize the TOD clock and the CPU timer of
270  * the boot cpu.
271  */
272 void __init time_init(void)
273 {
274         /* Reset time synchronization interfaces. */
275         etr_reset();
276         stp_reset();
277 
278         /* request the clock comparator external interrupt */
279         if (register_external_irq(EXT_IRQ_CLK_COMP, clock_comparator_interrupt))
280                 panic("Couldn't request external interrupt 0x1004");
281 
282         /* request the timing alert external interrupt */
283         if (register_external_irq(EXT_IRQ_TIMING_ALERT, timing_alert_interrupt))
284                 panic("Couldn't request external interrupt 0x1406");
285 
286         if (clocksource_register(&clocksource_tod) != 0)
287                 panic("Could not register TOD clock source");
288 
289         /* Enable TOD clock interrupts on the boot cpu. */
290         init_cpu_timer();
291 
292         /* Enable cpu timer interrupts on the boot cpu. */
293         vtime_init();
294 }
295 
296 /*
297  * The time is "clock". old is what we think the time is.
298  * Adjust the value by a multiple of jiffies and add the delta to ntp.
299  * "delay" is an approximation how long the synchronization took. If
300  * the time correction is positive, then "delay" is subtracted from
301  * the time difference and only the remaining part is passed to ntp.
302  */
303 static unsigned long long adjust_time(unsigned long long old,
304                                       unsigned long long clock,
305                                       unsigned long long delay)
306 {
307         unsigned long long delta, ticks;
308         struct timex adjust;
309 
310         if (clock > old) {
311                 /* It is later than we thought. */
312                 delta = ticks = clock - old;
313                 delta = ticks = (delta < delay) ? 0 : delta - delay;
314                 delta -= do_div(ticks, CLK_TICKS_PER_JIFFY);
315                 adjust.offset = ticks * (1000000 / HZ);
316         } else {
317                 /* It is earlier than we thought. */
318                 delta = ticks = old - clock;
319                 delta -= do_div(ticks, CLK_TICKS_PER_JIFFY);
320                 delta = -delta;
321                 adjust.offset = -ticks * (1000000 / HZ);
322         }
323         sched_clock_base_cc += delta;
324         if (adjust.offset != 0) {
325                 pr_notice("The ETR interface has adjusted the clock "
326                           "by %li microseconds\n", adjust.offset);
327                 adjust.modes = ADJ_OFFSET_SINGLESHOT;
328                 do_adjtimex(&adjust);
329         }
330         return delta;
331 }
332 
333 static DEFINE_PER_CPU(atomic_t, clock_sync_word);
334 static DEFINE_MUTEX(clock_sync_mutex);
335 static unsigned long clock_sync_flags;
336 
337 #define CLOCK_SYNC_HAS_ETR      0
338 #define CLOCK_SYNC_HAS_STP      1
339 #define CLOCK_SYNC_ETR          2
340 #define CLOCK_SYNC_STP          3
341 
342 /*
343  * The synchronous get_clock function. It will write the current clock
344  * value to the clock pointer and return 0 if the clock is in sync with
345  * the external time source. If the clock mode is local it will return
346  * -EOPNOTSUPP and -EAGAIN if the clock is not in sync with the external
347  * reference.
348  */
349 int get_sync_clock(unsigned long long *clock)
350 {
351         atomic_t *sw_ptr;
352         unsigned int sw0, sw1;
353 
354         sw_ptr = &get_cpu_var(clock_sync_word);
355         sw0 = atomic_read(sw_ptr);
356         *clock = get_tod_clock();
357         sw1 = atomic_read(sw_ptr);
358         put_cpu_var(clock_sync_word);
359         if (sw0 == sw1 && (sw0 & 0x80000000U))
360                 /* Success: time is in sync. */
361                 return 0;
362         if (!test_bit(CLOCK_SYNC_HAS_ETR, &clock_sync_flags) &&
363             !test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
364                 return -EOPNOTSUPP;
365         if (!test_bit(CLOCK_SYNC_ETR, &clock_sync_flags) &&
366             !test_bit(CLOCK_SYNC_STP, &clock_sync_flags))
367                 return -EACCES;
368         return -EAGAIN;
369 }
370 EXPORT_SYMBOL(get_sync_clock);
371 
372 /*
373  * Make get_sync_clock return -EAGAIN.
374  */
375 static void disable_sync_clock(void *dummy)
376 {
377         atomic_t *sw_ptr = this_cpu_ptr(&clock_sync_word);
378         /*
379          * Clear the in-sync bit 2^31. All get_sync_clock calls will
380          * fail until the sync bit is turned back on. In addition
381          * increase the "sequence" counter to avoid the race of an
382          * etr event and the complete recovery against get_sync_clock.
383          */
384         atomic_clear_mask(0x80000000, sw_ptr);
385         atomic_inc(sw_ptr);
386 }
387 
388 /*
389  * Make get_sync_clock return 0 again.
390  * Needs to be called from a context disabled for preemption.
391  */
392 static void enable_sync_clock(void)
393 {
394         atomic_t *sw_ptr = this_cpu_ptr(&clock_sync_word);
395         atomic_set_mask(0x80000000, sw_ptr);
396 }
397 
398 /*
399  * Function to check if the clock is in sync.
400  */
401 static inline int check_sync_clock(void)
402 {
403         atomic_t *sw_ptr;
404         int rc;
405 
406         sw_ptr = &get_cpu_var(clock_sync_word);
407         rc = (atomic_read(sw_ptr) & 0x80000000U) != 0;
408         put_cpu_var(clock_sync_word);
409         return rc;
410 }
411 
412 /* Single threaded workqueue used for etr and stp sync events */
413 static struct workqueue_struct *time_sync_wq;
414 
415 static void __init time_init_wq(void)
416 {
417         if (time_sync_wq)
418                 return;
419         time_sync_wq = create_singlethread_workqueue("timesync");
420 }
421 
422 /*
423  * External Time Reference (ETR) code.
424  */
425 static int etr_port0_online;
426 static int etr_port1_online;
427 static int etr_steai_available;
428 
429 static int __init early_parse_etr(char *p)
430 {
431         if (strncmp(p, "off", 3) == 0)
432                 etr_port0_online = etr_port1_online = 0;
433         else if (strncmp(p, "port0", 5) == 0)
434                 etr_port0_online = 1;
435         else if (strncmp(p, "port1", 5) == 0)
436                 etr_port1_online = 1;
437         else if (strncmp(p, "on", 2) == 0)
438                 etr_port0_online = etr_port1_online = 1;
439         return 0;
440 }
441 early_param("etr", early_parse_etr);
442 
443 enum etr_event {
444         ETR_EVENT_PORT0_CHANGE,
445         ETR_EVENT_PORT1_CHANGE,
446         ETR_EVENT_PORT_ALERT,
447         ETR_EVENT_SYNC_CHECK,
448         ETR_EVENT_SWITCH_LOCAL,
449         ETR_EVENT_UPDATE,
450 };
451 
452 /*
453  * Valid bit combinations of the eacr register are (x = don't care):
454  * e0 e1 dp p0 p1 ea es sl
455  *  0  0  x  0  0  0  0  0  initial, disabled state
456  *  0  0  x  0  1  1  0  0  port 1 online
457  *  0  0  x  1  0  1  0  0  port 0 online
458  *  0  0  x  1  1  1  0  0  both ports online
459  *  0  1  x  0  1  1  0  0  port 1 online and usable, ETR or PPS mode
460  *  0  1  x  0  1  1  0  1  port 1 online, usable and ETR mode
461  *  0  1  x  0  1  1  1  0  port 1 online, usable, PPS mode, in-sync
462  *  0  1  x  0  1  1  1  1  port 1 online, usable, ETR mode, in-sync
463  *  0  1  x  1  1  1  0  0  both ports online, port 1 usable
464  *  0  1  x  1  1  1  1  0  both ports online, port 1 usable, PPS mode, in-sync
465  *  0  1  x  1  1  1  1  1  both ports online, port 1 usable, ETR mode, in-sync
466  *  1  0  x  1  0  1  0  0  port 0 online and usable, ETR or PPS mode
467  *  1  0  x  1  0  1  0  1  port 0 online, usable and ETR mode
468  *  1  0  x  1  0  1  1  0  port 0 online, usable, PPS mode, in-sync
469  *  1  0  x  1  0  1  1  1  port 0 online, usable, ETR mode, in-sync
470  *  1  0  x  1  1  1  0  0  both ports online, port 0 usable
471  *  1  0  x  1  1  1  1  0  both ports online, port 0 usable, PPS mode, in-sync
472  *  1  0  x  1  1  1  1  1  both ports online, port 0 usable, ETR mode, in-sync
473  *  1  1  x  1  1  1  1  0  both ports online & usable, ETR, in-sync
474  *  1  1  x  1  1  1  1  1  both ports online & usable, ETR, in-sync
475  */
476 static struct etr_eacr etr_eacr;
477 static u64 etr_tolec;                   /* time of last eacr update */
478 static struct etr_aib etr_port0;
479 static int etr_port0_uptodate;
480 static struct etr_aib etr_port1;
481 static int etr_port1_uptodate;
482 static unsigned long etr_events;
483 static struct timer_list etr_timer;
484 
485 static void etr_timeout(unsigned long dummy);
486 static void etr_work_fn(struct work_struct *work);
487 static DEFINE_MUTEX(etr_work_mutex);
488 static DECLARE_WORK(etr_work, etr_work_fn);
489 
490 /*
491  * Reset ETR attachment.
492  */
493 static void etr_reset(void)
494 {
495         etr_eacr =  (struct etr_eacr) {
496                 .e0 = 0, .e1 = 0, ._pad0 = 4, .dp = 0,
497                 .p0 = 0, .p1 = 0, ._pad1 = 0, .ea = 0,
498                 .es = 0, .sl = 0 };
499         if (etr_setr(&etr_eacr) == 0) {
500                 etr_tolec = get_tod_clock();
501                 set_bit(CLOCK_SYNC_HAS_ETR, &clock_sync_flags);
502                 if (etr_port0_online && etr_port1_online)
503                         set_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
504         } else if (etr_port0_online || etr_port1_online) {
505                 pr_warning("The real or virtual hardware system does "
506                            "not provide an ETR interface\n");
507                 etr_port0_online = etr_port1_online = 0;
508         }
509 }
510 
511 static int __init etr_init(void)
512 {
513         struct etr_aib aib;
514 
515         if (!test_bit(CLOCK_SYNC_HAS_ETR, &clock_sync_flags))
516                 return 0;
517         time_init_wq();
518         /* Check if this machine has the steai instruction. */
519         if (etr_steai(&aib, ETR_STEAI_STEPPING_PORT) == 0)
520                 etr_steai_available = 1;
521         setup_timer(&etr_timer, etr_timeout, 0UL);
522         if (etr_port0_online) {
523                 set_bit(ETR_EVENT_PORT0_CHANGE, &etr_events);
524                 queue_work(time_sync_wq, &etr_work);
525         }
526         if (etr_port1_online) {
527                 set_bit(ETR_EVENT_PORT1_CHANGE, &etr_events);
528                 queue_work(time_sync_wq, &etr_work);
529         }
530         return 0;
531 }
532 
533 arch_initcall(etr_init);
534 
535 /*
536  * Two sorts of ETR machine checks. The architecture reads:
537  * "When a machine-check niterruption occurs and if a switch-to-local or
538  *  ETR-sync-check interrupt request is pending but disabled, this pending
539  *  disabled interruption request is indicated and is cleared".
540  * Which means that we can get etr_switch_to_local events from the machine
541  * check handler although the interruption condition is disabled. Lovely..
542  */
543 
544 /*
545  * Switch to local machine check. This is called when the last usable
546  * ETR port goes inactive. After switch to local the clock is not in sync.
547  */
548 void etr_switch_to_local(void)
549 {
550         if (!etr_eacr.sl)
551                 return;
552         disable_sync_clock(NULL);
553         if (!test_and_set_bit(ETR_EVENT_SWITCH_LOCAL, &etr_events)) {
554                 etr_eacr.es = etr_eacr.sl = 0;
555                 etr_setr(&etr_eacr);
556                 queue_work(time_sync_wq, &etr_work);
557         }
558 }
559 
560 /*
561  * ETR sync check machine check. This is called when the ETR OTE and the
562  * local clock OTE are farther apart than the ETR sync check tolerance.
563  * After a ETR sync check the clock is not in sync. The machine check
564  * is broadcasted to all cpus at the same time.
565  */
566 void etr_sync_check(void)
567 {
568         if (!etr_eacr.es)
569                 return;
570         disable_sync_clock(NULL);
571         if (!test_and_set_bit(ETR_EVENT_SYNC_CHECK, &etr_events)) {
572                 etr_eacr.es = 0;
573                 etr_setr(&etr_eacr);
574                 queue_work(time_sync_wq, &etr_work);
575         }
576 }
577 
578 /*
579  * ETR timing alert. There are two causes:
580  * 1) port state change, check the usability of the port
581  * 2) port alert, one of the ETR-data-validity bits (v1-v2 bits of the
582  *    sldr-status word) or ETR-data word 1 (edf1) or ETR-data word 3 (edf3)
583  *    or ETR-data word 4 (edf4) has changed.
584  */
585 static void etr_timing_alert(struct etr_irq_parm *intparm)
586 {
587         if (intparm->pc0)
588                 /* ETR port 0 state change. */
589                 set_bit(ETR_EVENT_PORT0_CHANGE, &etr_events);
590         if (intparm->pc1)
591                 /* ETR port 1 state change. */
592                 set_bit(ETR_EVENT_PORT1_CHANGE, &etr_events);
593         if (intparm->eai)
594                 /*
595                  * ETR port alert on either port 0, 1 or both.
596                  * Both ports are not up-to-date now.
597                  */
598                 set_bit(ETR_EVENT_PORT_ALERT, &etr_events);
599         queue_work(time_sync_wq, &etr_work);
600 }
601 
602 static void etr_timeout(unsigned long dummy)
603 {
604         set_bit(ETR_EVENT_UPDATE, &etr_events);
605         queue_work(time_sync_wq, &etr_work);
606 }
607 
608 /*
609  * Check if the etr mode is pss.
610  */
611 static inline int etr_mode_is_pps(struct etr_eacr eacr)
612 {
613         return eacr.es && !eacr.sl;
614 }
615 
616 /*
617  * Check if the etr mode is etr.
618  */
619 static inline int etr_mode_is_etr(struct etr_eacr eacr)
620 {
621         return eacr.es && eacr.sl;
622 }
623 
624 /*
625  * Check if the port can be used for TOD synchronization.
626  * For PPS mode the port has to receive OTEs. For ETR mode
627  * the port has to receive OTEs, the ETR stepping bit has to
628  * be zero and the validity bits for data frame 1, 2, and 3
629  * have to be 1.
630  */
631 static int etr_port_valid(struct etr_aib *aib, int port)
632 {
633         unsigned int psc;
634 
635         /* Check that this port is receiving OTEs. */
636         if (aib->tsp == 0)
637                 return 0;
638 
639         psc = port ? aib->esw.psc1 : aib->esw.psc0;
640         if (psc == etr_lpsc_pps_mode)
641                 return 1;
642         if (psc == etr_lpsc_operational_step)
643                 return !aib->esw.y && aib->slsw.v1 &&
644                         aib->slsw.v2 && aib->slsw.v3;
645         return 0;
646 }
647 
648 /*
649  * Check if two ports are on the same network.
650  */
651 static int etr_compare_network(struct etr_aib *aib1, struct etr_aib *aib2)
652 {
653         // FIXME: any other fields we have to compare?
654         return aib1->edf1.net_id == aib2->edf1.net_id;
655 }
656 
657 /*
658  * Wrapper for etr_stei that converts physical port states
659  * to logical port states to be consistent with the output
660  * of stetr (see etr_psc vs. etr_lpsc).
661  */
662 static void etr_steai_cv(struct etr_aib *aib, unsigned int func)
663 {
664         BUG_ON(etr_steai(aib, func) != 0);
665         /* Convert port state to logical port state. */
666         if (aib->esw.psc0 == 1)
667                 aib->esw.psc0 = 2;
668         else if (aib->esw.psc0 == 0 && aib->esw.p == 0)
669                 aib->esw.psc0 = 1;
670         if (aib->esw.psc1 == 1)
671                 aib->esw.psc1 = 2;
672         else if (aib->esw.psc1 == 0 && aib->esw.p == 1)
673                 aib->esw.psc1 = 1;
674 }
675 
676 /*
677  * Check if the aib a2 is still connected to the same attachment as
678  * aib a1, the etv values differ by one and a2 is valid.
679  */
680 static int etr_aib_follows(struct etr_aib *a1, struct etr_aib *a2, int p)
681 {
682         int state_a1, state_a2;
683 
684         /* Paranoia check: e0/e1 should better be the same. */
685         if (a1->esw.eacr.e0 != a2->esw.eacr.e0 ||
686             a1->esw.eacr.e1 != a2->esw.eacr.e1)
687                 return 0;
688 
689         /* Still connected to the same etr ? */
690         state_a1 = p ? a1->esw.psc1 : a1->esw.psc0;
691         state_a2 = p ? a2->esw.psc1 : a2->esw.psc0;
692         if (state_a1 == etr_lpsc_operational_step) {
693                 if (state_a2 != etr_lpsc_operational_step ||
694                     a1->edf1.net_id != a2->edf1.net_id ||
695                     a1->edf1.etr_id != a2->edf1.etr_id ||
696                     a1->edf1.etr_pn != a2->edf1.etr_pn)
697                         return 0;
698         } else if (state_a2 != etr_lpsc_pps_mode)
699                 return 0;
700 
701         /* The ETV value of a2 needs to be ETV of a1 + 1. */
702         if (a1->edf2.etv + 1 != a2->edf2.etv)
703                 return 0;
704 
705         if (!etr_port_valid(a2, p))
706                 return 0;
707 
708         return 1;
709 }
710 
711 struct clock_sync_data {
712         atomic_t cpus;
713         int in_sync;
714         unsigned long long fixup_cc;
715         int etr_port;
716         struct etr_aib *etr_aib;
717 };
718 
719 static void clock_sync_cpu(struct clock_sync_data *sync)
720 {
721         atomic_dec(&sync->cpus);
722         enable_sync_clock();
723         /*
724          * This looks like a busy wait loop but it isn't. etr_sync_cpus
725          * is called on all other cpus while the TOD clocks is stopped.
726          * __udelay will stop the cpu on an enabled wait psw until the
727          * TOD is running again.
728          */
729         while (sync->in_sync == 0) {
730                 __udelay(1);
731                 /*
732                  * A different cpu changes *in_sync. Therefore use
733                  * barrier() to force memory access.
734                  */
735                 barrier();
736         }
737         if (sync->in_sync != 1)
738                 /* Didn't work. Clear per-cpu in sync bit again. */
739                 disable_sync_clock(NULL);
740         /*
741          * This round of TOD syncing is done. Set the clock comparator
742          * to the next tick and let the processor continue.
743          */
744         fixup_clock_comparator(sync->fixup_cc);
745 }
746 
747 /*
748  * Sync the TOD clock using the port referred to by aibp. This port
749  * has to be enabled and the other port has to be disabled. The
750  * last eacr update has to be more than 1.6 seconds in the past.
751  */
752 static int etr_sync_clock(void *data)
753 {
754         static int first;
755         unsigned long long clock, old_clock, delay, delta;
756         struct clock_sync_data *etr_sync;
757         struct etr_aib *sync_port, *aib;
758         int port;
759         int rc;
760 
761         etr_sync = data;
762 
763         if (xchg(&first, 1) == 1) {
764                 /* Slave */
765                 clock_sync_cpu(etr_sync);
766                 return 0;
767         }
768 
769         /* Wait until all other cpus entered the sync function. */
770         while (atomic_read(&etr_sync->cpus) != 0)
771                 cpu_relax();
772 
773         port = etr_sync->etr_port;
774         aib = etr_sync->etr_aib;
775         sync_port = (port == 0) ? &etr_port0 : &etr_port1;
776         enable_sync_clock();
777 
778         /* Set clock to next OTE. */
779         __ctl_set_bit(14, 21);
780         __ctl_set_bit(0, 29);
781         clock = ((unsigned long long) (aib->edf2.etv + 1)) << 32;
782         old_clock = get_tod_clock();
783         if (set_tod_clock(clock) == 0) {
784                 __udelay(1);    /* Wait for the clock to start. */
785                 __ctl_clear_bit(0, 29);
786                 __ctl_clear_bit(14, 21);
787                 etr_stetr(aib);
788                 /* Adjust Linux timing variables. */
789                 delay = (unsigned long long)
790                         (aib->edf2.etv - sync_port->edf2.etv) << 32;
791                 delta = adjust_time(old_clock, clock, delay);
792                 etr_sync->fixup_cc = delta;
793                 fixup_clock_comparator(delta);
794                 /* Verify that the clock is properly set. */
795                 if (!etr_aib_follows(sync_port, aib, port)) {
796                         /* Didn't work. */
797                         disable_sync_clock(NULL);
798                         etr_sync->in_sync = -EAGAIN;
799                         rc = -EAGAIN;
800                 } else {
801                         etr_sync->in_sync = 1;
802                         rc = 0;
803                 }
804         } else {
805                 /* Could not set the clock ?!? */
806                 __ctl_clear_bit(0, 29);
807                 __ctl_clear_bit(14, 21);
808                 disable_sync_clock(NULL);
809                 etr_sync->in_sync = -EAGAIN;
810                 rc = -EAGAIN;
811         }
812         xchg(&first, 0);
813         return rc;
814 }
815 
816 static int etr_sync_clock_stop(struct etr_aib *aib, int port)
817 {
818         struct clock_sync_data etr_sync;
819         struct etr_aib *sync_port;
820         int follows;
821         int rc;
822 
823         /* Check if the current aib is adjacent to the sync port aib. */
824         sync_port = (port == 0) ? &etr_port0 : &etr_port1;
825         follows = etr_aib_follows(sync_port, aib, port);
826         memcpy(sync_port, aib, sizeof(*aib));
827         if (!follows)
828                 return -EAGAIN;
829         memset(&etr_sync, 0, sizeof(etr_sync));
830         etr_sync.etr_aib = aib;
831         etr_sync.etr_port = port;
832         get_online_cpus();
833         atomic_set(&etr_sync.cpus, num_online_cpus() - 1);
834         rc = stop_machine(etr_sync_clock, &etr_sync, cpu_online_mask);
835         put_online_cpus();
836         return rc;
837 }
838 
839 /*
840  * Handle the immediate effects of the different events.
841  * The port change event is used for online/offline changes.
842  */
843 static struct etr_eacr etr_handle_events(struct etr_eacr eacr)
844 {
845         if (test_and_clear_bit(ETR_EVENT_SYNC_CHECK, &etr_events))
846                 eacr.es = 0;
847         if (test_and_clear_bit(ETR_EVENT_SWITCH_LOCAL, &etr_events))
848                 eacr.es = eacr.sl = 0;
849         if (test_and_clear_bit(ETR_EVENT_PORT_ALERT, &etr_events))
850                 etr_port0_uptodate = etr_port1_uptodate = 0;
851 
852         if (test_and_clear_bit(ETR_EVENT_PORT0_CHANGE, &etr_events)) {
853                 if (eacr.e0)
854                         /*
855                          * Port change of an enabled port. We have to
856                          * assume that this can have caused an stepping
857                          * port switch.
858                          */
859                         etr_tolec = get_tod_clock();
860                 eacr.p0 = etr_port0_online;
861                 if (!eacr.p0)
862                         eacr.e0 = 0;
863                 etr_port0_uptodate = 0;
864         }
865         if (test_and_clear_bit(ETR_EVENT_PORT1_CHANGE, &etr_events)) {
866                 if (eacr.e1)
867                         /*
868                          * Port change of an enabled port. We have to
869                          * assume that this can have caused an stepping
870                          * port switch.
871                          */
872                         etr_tolec = get_tod_clock();
873                 eacr.p1 = etr_port1_online;
874                 if (!eacr.p1)
875                         eacr.e1 = 0;
876                 etr_port1_uptodate = 0;
877         }
878         clear_bit(ETR_EVENT_UPDATE, &etr_events);
879         return eacr;
880 }
881 
882 /*
883  * Set up a timer that expires after the etr_tolec + 1.6 seconds if
884  * one of the ports needs an update.
885  */
886 static void etr_set_tolec_timeout(unsigned long long now)
887 {
888         unsigned long micros;
889 
890         if ((!etr_eacr.p0 || etr_port0_uptodate) &&
891             (!etr_eacr.p1 || etr_port1_uptodate))
892                 return;
893         micros = (now > etr_tolec) ? ((now - etr_tolec) >> 12) : 0;
894         micros = (micros > 1600000) ? 0 : 1600000 - micros;
895         mod_timer(&etr_timer, jiffies + (micros * HZ) / 1000000 + 1);
896 }
897 
898 /*
899  * Set up a time that expires after 1/2 second.
900  */
901 static void etr_set_sync_timeout(void)
902 {
903         mod_timer(&etr_timer, jiffies + HZ/2);
904 }
905 
906 /*
907  * Update the aib information for one or both ports.
908  */
909 static struct etr_eacr etr_handle_update(struct etr_aib *aib,
910                                          struct etr_eacr eacr)
911 {
912         /* With both ports disabled the aib information is useless. */
913         if (!eacr.e0 && !eacr.e1)
914                 return eacr;
915 
916         /* Update port0 or port1 with aib stored in etr_work_fn. */
917         if (aib->esw.q == 0) {
918                 /* Information for port 0 stored. */
919                 if (eacr.p0 && !etr_port0_uptodate) {
920                         etr_port0 = *aib;
921                         if (etr_port0_online)
922                                 etr_port0_uptodate = 1;
923                 }
924         } else {
925                 /* Information for port 1 stored. */
926                 if (eacr.p1 && !etr_port1_uptodate) {
927                         etr_port1 = *aib;
928                         if (etr_port0_online)
929                                 etr_port1_uptodate = 1;
930                 }
931         }
932 
933         /*
934          * Do not try to get the alternate port aib if the clock
935          * is not in sync yet.
936          */
937         if (!eacr.es || !check_sync_clock())
938                 return eacr;
939 
940         /*
941          * If steai is available we can get the information about
942          * the other port immediately. If only stetr is available the
943          * data-port bit toggle has to be used.
944          */
945         if (etr_steai_available) {
946                 if (eacr.p0 && !etr_port0_uptodate) {
947                         etr_steai_cv(&etr_port0, ETR_STEAI_PORT_0);
948                         etr_port0_uptodate = 1;
949                 }
950                 if (eacr.p1 && !etr_port1_uptodate) {
951                         etr_steai_cv(&etr_port1, ETR_STEAI_PORT_1);
952                         etr_port1_uptodate = 1;
953                 }
954         } else {
955                 /*
956                  * One port was updated above, if the other
957                  * port is not uptodate toggle dp bit.
958                  */
959                 if ((eacr.p0 && !etr_port0_uptodate) ||
960                     (eacr.p1 && !etr_port1_uptodate))
961                         eacr.dp ^= 1;
962                 else
963                         eacr.dp = 0;
964         }
965         return eacr;
966 }
967 
968 /*
969  * Write new etr control register if it differs from the current one.
970  * Return 1 if etr_tolec has been updated as well.
971  */
972 static void etr_update_eacr(struct etr_eacr eacr)
973 {
974         int dp_changed;
975 
976         if (memcmp(&etr_eacr, &eacr, sizeof(eacr)) == 0)
977                 /* No change, return. */
978                 return;
979         /*
980          * The disable of an active port of the change of the data port
981          * bit can/will cause a change in the data port.
982          */
983         dp_changed = etr_eacr.e0 > eacr.e0 || etr_eacr.e1 > eacr.e1 ||
984                 (etr_eacr.dp ^ eacr.dp) != 0;
985         etr_eacr = eacr;
986         etr_setr(&etr_eacr);
987         if (dp_changed)
988                 etr_tolec = get_tod_clock();
989 }
990 
991 /*
992  * ETR work. In this function you'll find the main logic. In
993  * particular this is the only function that calls etr_update_eacr(),
994  * it "controls" the etr control register.
995  */
996 static void etr_work_fn(struct work_struct *work)
997 {
998         unsigned long long now;
999         struct etr_eacr eacr;
1000         struct etr_aib aib;
1001         int sync_port;
1002 
1003         /* prevent multiple execution. */
1004         mutex_lock(&etr_work_mutex);
1005 
1006         /* Create working copy of etr_eacr. */
1007         eacr = etr_eacr;
1008 
1009         /* Check for the different events and their immediate effects. */
1010         eacr = etr_handle_events(eacr);
1011 
1012         /* Check if ETR is supposed to be active. */
1013         eacr.ea = eacr.p0 || eacr.p1;
1014         if (!eacr.ea) {
1015                 /* Both ports offline. Reset everything. */
1016                 eacr.dp = eacr.es = eacr.sl = 0;
1017                 on_each_cpu(disable_sync_clock, NULL, 1);
1018                 del_timer_sync(&etr_timer);
1019                 etr_update_eacr(eacr);
1020                 goto out_unlock;
1021         }
1022 
1023         /* Store aib to get the current ETR status word. */
1024         BUG_ON(etr_stetr(&aib) != 0);
1025         etr_port0.esw = etr_port1.esw = aib.esw;        /* Copy status word. */
1026         now = get_tod_clock();
1027 
1028         /*
1029          * Update the port information if the last stepping port change
1030          * or data port change is older than 1.6 seconds.
1031          */
1032         if (now >= etr_tolec + (1600000 << 12))
1033                 eacr = etr_handle_update(&aib, eacr);
1034 
1035         /*
1036          * Select ports to enable. The preferred synchronization mode is PPS.
1037          * If a port can be enabled depends on a number of things:
1038          * 1) The port needs to be online and uptodate. A port is not
1039          *    disabled just because it is not uptodate, but it is only
1040          *    enabled if it is uptodate.
1041          * 2) The port needs to have the same mode (pps / etr).
1042          * 3) The port needs to be usable -> etr_port_valid() == 1
1043          * 4) To enable the second port the clock needs to be in sync.
1044          * 5) If both ports are useable and are ETR ports, the network id
1045          *    has to be the same.
1046          * The eacr.sl bit is used to indicate etr mode vs. pps mode.
1047          */
1048         if (eacr.p0 && aib.esw.psc0 == etr_lpsc_pps_mode) {
1049                 eacr.sl = 0;
1050                 eacr.e0 = 1;
1051                 if (!etr_mode_is_pps(etr_eacr))
1052                         eacr.es = 0;
1053                 if (!eacr.es || !eacr.p1 || aib.esw.psc1 != etr_lpsc_pps_mode)
1054                         eacr.e1 = 0;
1055                 // FIXME: uptodate checks ?
1056                 else if (etr_port0_uptodate && etr_port1_uptodate)
1057                         eacr.e1 = 1;
1058                 sync_port = (etr_port0_uptodate &&
1059                              etr_port_valid(&etr_port0, 0)) ? 0 : -1;
1060         } else if (eacr.p1 && aib.esw.psc1 == etr_lpsc_pps_mode) {
1061                 eacr.sl = 0;
1062                 eacr.e0 = 0;
1063                 eacr.e1 = 1;
1064                 if (!etr_mode_is_pps(etr_eacr))
1065                         eacr.es = 0;
1066                 sync_port = (etr_port1_uptodate &&
1067                              etr_port_valid(&etr_port1, 1)) ? 1 : -1;
1068         } else if (eacr.p0 && aib.esw.psc0 == etr_lpsc_operational_step) {
1069                 eacr.sl = 1;
1070                 eacr.e0 = 1;
1071                 if (!etr_mode_is_etr(etr_eacr))
1072                         eacr.es = 0;
1073                 if (!eacr.es || !eacr.p1 ||
1074                     aib.esw.psc1 != etr_lpsc_operational_alt)
1075                         eacr.e1 = 0;
1076                 else if (etr_port0_uptodate && etr_port1_uptodate &&
1077                          etr_compare_network(&etr_port0, &etr_port1))
1078                         eacr.e1 = 1;
1079                 sync_port = (etr_port0_uptodate &&
1080                              etr_port_valid(&etr_port0, 0)) ? 0 : -1;
1081         } else if (eacr.p1 && aib.esw.psc1 == etr_lpsc_operational_step) {
1082                 eacr.sl = 1;
1083                 eacr.e0 = 0;
1084                 eacr.e1 = 1;
1085                 if (!etr_mode_is_etr(etr_eacr))
1086                         eacr.es = 0;
1087                 sync_port = (etr_port1_uptodate &&
1088                              etr_port_valid(&etr_port1, 1)) ? 1 : -1;
1089         } else {
1090                 /* Both ports not usable. */
1091                 eacr.es = eacr.sl = 0;
1092                 sync_port = -1;
1093         }
1094 
1095         /*
1096          * If the clock is in sync just update the eacr and return.
1097          * If there is no valid sync port wait for a port update.
1098          */
1099         if ((eacr.es && check_sync_clock()) || sync_port < 0) {
1100                 etr_update_eacr(eacr);
1101                 etr_set_tolec_timeout(now);
1102                 goto out_unlock;
1103         }
1104 
1105         /*
1106          * Prepare control register for clock syncing
1107          * (reset data port bit, set sync check control.
1108          */
1109         eacr.dp = 0;
1110         eacr.es = 1;
1111 
1112         /*
1113          * Update eacr and try to synchronize the clock. If the update
1114          * of eacr caused a stepping port switch (or if we have to
1115          * assume that a stepping port switch has occurred) or the
1116          * clock syncing failed, reset the sync check control bit
1117          * and set up a timer to try again after 0.5 seconds
1118          */
1119         etr_update_eacr(eacr);
1120         if (now < etr_tolec + (1600000 << 12) ||
1121             etr_sync_clock_stop(&aib, sync_port) != 0) {
1122                 /* Sync failed. Try again in 1/2 second. */
1123                 eacr.es = 0;
1124                 etr_update_eacr(eacr);
1125                 etr_set_sync_timeout();
1126         } else
1127                 etr_set_tolec_timeout(now);
1128 out_unlock:
1129         mutex_unlock(&etr_work_mutex);
1130 }
1131 
1132 /*
1133  * Sysfs interface functions
1134  */
1135 static struct bus_type etr_subsys = {
1136         .name           = "etr",
1137         .dev_name       = "etr",
1138 };
1139 
1140 static struct device etr_port0_dev = {
1141         .id     = 0,
1142         .bus    = &etr_subsys,
1143 };
1144 
1145 static struct device etr_port1_dev = {
1146         .id     = 1,
1147         .bus    = &etr_subsys,
1148 };
1149 
1150 /*
1151  * ETR subsys attributes
1152  */
1153 static ssize_t etr_stepping_port_show(struct device *dev,
1154                                         struct device_attribute *attr,
1155                                         char *buf)
1156 {
1157         return sprintf(buf, "%i\n", etr_port0.esw.p);
1158 }
1159 
1160 static DEVICE_ATTR(stepping_port, 0400, etr_stepping_port_show, NULL);
1161 
1162 static ssize_t etr_stepping_mode_show(struct device *dev,
1163                                         struct device_attribute *attr,
1164                                         char *buf)
1165 {
1166         char *mode_str;
1167 
1168         if (etr_mode_is_pps(etr_eacr))
1169                 mode_str = "pps";
1170         else if (etr_mode_is_etr(etr_eacr))
1171                 mode_str = "etr";
1172         else
1173                 mode_str = "local";
1174         return sprintf(buf, "%s\n", mode_str);
1175 }
1176 
1177 static DEVICE_ATTR(stepping_mode, 0400, etr_stepping_mode_show, NULL);
1178 
1179 /*
1180  * ETR port attributes
1181  */
1182 static inline struct etr_aib *etr_aib_from_dev(struct device *dev)
1183 {
1184         if (dev == &etr_port0_dev)
1185                 return etr_port0_online ? &etr_port0 : NULL;
1186         else
1187                 return etr_port1_online ? &etr_port1 : NULL;
1188 }
1189 
1190 static ssize_t etr_online_show(struct device *dev,
1191                                 struct device_attribute *attr,
1192                                 char *buf)
1193 {
1194         unsigned int online;
1195 
1196         online = (dev == &etr_port0_dev) ? etr_port0_online : etr_port1_online;
1197         return sprintf(buf, "%i\n", online);
1198 }
1199 
1200 static ssize_t etr_online_store(struct device *dev,
1201                                 struct device_attribute *attr,
1202                                 const char *buf, size_t count)
1203 {
1204         unsigned int value;
1205 
1206         value = simple_strtoul(buf, NULL, 0);
1207         if (value != 0 && value != 1)
1208                 return -EINVAL;
1209         if (!test_bit(CLOCK_SYNC_HAS_ETR, &clock_sync_flags))
1210                 return -EOPNOTSUPP;
1211         mutex_lock(&clock_sync_mutex);
1212         if (dev == &etr_port0_dev) {
1213                 if (etr_port0_online == value)
1214                         goto out;       /* Nothing to do. */
1215                 etr_port0_online = value;
1216                 if (etr_port0_online && etr_port1_online)
1217                         set_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
1218                 else
1219                         clear_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
1220                 set_bit(ETR_EVENT_PORT0_CHANGE, &etr_events);
1221                 queue_work(time_sync_wq, &etr_work);
1222         } else {
1223                 if (etr_port1_online == value)
1224                         goto out;       /* Nothing to do. */
1225                 etr_port1_online = value;
1226                 if (etr_port0_online && etr_port1_online)
1227                         set_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
1228                 else
1229                         clear_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
1230                 set_bit(ETR_EVENT_PORT1_CHANGE, &etr_events);
1231                 queue_work(time_sync_wq, &etr_work);
1232         }
1233 out:
1234         mutex_unlock(&clock_sync_mutex);
1235         return count;
1236 }
1237 
1238 static DEVICE_ATTR(online, 0600, etr_online_show, etr_online_store);
1239 
1240 static ssize_t etr_stepping_control_show(struct device *dev,
1241                                         struct device_attribute *attr,
1242                                         char *buf)
1243 {
1244         return sprintf(buf, "%i\n", (dev == &etr_port0_dev) ?
1245                        etr_eacr.e0 : etr_eacr.e1);
1246 }
1247 
1248 static DEVICE_ATTR(stepping_control, 0400, etr_stepping_control_show, NULL);
1249 
1250 static ssize_t etr_mode_code_show(struct device *dev,
1251                                 struct device_attribute *attr, char *buf)
1252 {
1253         if (!etr_port0_online && !etr_port1_online)
1254                 /* Status word is not uptodate if both ports are offline. */
1255                 return -ENODATA;
1256         return sprintf(buf, "%i\n", (dev == &etr_port0_dev) ?
1257                        etr_port0.esw.psc0 : etr_port0.esw.psc1);
1258 }
1259 
1260 static DEVICE_ATTR(state_code, 0400, etr_mode_code_show, NULL);
1261 
1262 static ssize_t etr_untuned_show(struct device *dev,
1263                                 struct device_attribute *attr, char *buf)
1264 {
1265         struct etr_aib *aib = etr_aib_from_dev(dev);
1266 
1267         if (!aib || !aib->slsw.v1)
1268                 return -ENODATA;
1269         return sprintf(buf, "%i\n", aib->edf1.u);
1270 }
1271 
1272 static DEVICE_ATTR(untuned, 0400, etr_untuned_show, NULL);
1273 
1274 static ssize_t etr_network_id_show(struct device *dev,
1275                                 struct device_attribute *attr, char *buf)
1276 {
1277         struct etr_aib *aib = etr_aib_from_dev(dev);
1278 
1279         if (!aib || !aib->slsw.v1)
1280                 return -ENODATA;
1281         return sprintf(buf, "%i\n", aib->edf1.net_id);
1282 }
1283 
1284 static DEVICE_ATTR(network, 0400, etr_network_id_show, NULL);
1285 
1286 static ssize_t etr_id_show(struct device *dev,
1287                         struct device_attribute *attr, char *buf)
1288 {
1289         struct etr_aib *aib = etr_aib_from_dev(dev);
1290 
1291         if (!aib || !aib->slsw.v1)
1292                 return -ENODATA;
1293         return sprintf(buf, "%i\n", aib->edf1.etr_id);
1294 }
1295 
1296 static DEVICE_ATTR(id, 0400, etr_id_show, NULL);
1297 
1298 static ssize_t etr_port_number_show(struct device *dev,
1299                         struct device_attribute *attr, char *buf)
1300 {
1301         struct etr_aib *aib = etr_aib_from_dev(dev);
1302 
1303         if (!aib || !aib->slsw.v1)
1304                 return -ENODATA;
1305         return sprintf(buf, "%i\n", aib->edf1.etr_pn);
1306 }
1307 
1308 static DEVICE_ATTR(port, 0400, etr_port_number_show, NULL);
1309 
1310 static ssize_t etr_coupled_show(struct device *dev,
1311                         struct device_attribute *attr, char *buf)
1312 {
1313         struct etr_aib *aib = etr_aib_from_dev(dev);
1314 
1315         if (!aib || !aib->slsw.v3)
1316                 return -ENODATA;
1317         return sprintf(buf, "%i\n", aib->edf3.c);
1318 }
1319 
1320 static DEVICE_ATTR(coupled, 0400, etr_coupled_show, NULL);
1321 
1322 static ssize_t etr_local_time_show(struct device *dev,
1323                         struct device_attribute *attr, char *buf)
1324 {
1325         struct etr_aib *aib = etr_aib_from_dev(dev);
1326 
1327         if (!aib || !aib->slsw.v3)
1328                 return -ENODATA;
1329         return sprintf(buf, "%i\n", aib->edf3.blto);
1330 }
1331 
1332 static DEVICE_ATTR(local_time, 0400, etr_local_time_show, NULL);
1333 
1334 static ssize_t etr_utc_offset_show(struct device *dev,
1335                         struct device_attribute *attr, char *buf)
1336 {
1337         struct etr_aib *aib = etr_aib_from_dev(dev);
1338 
1339         if (!aib || !aib->slsw.v3)
1340                 return -ENODATA;
1341         return sprintf(buf, "%i\n", aib->edf3.buo);
1342 }
1343 
1344 static DEVICE_ATTR(utc_offset, 0400, etr_utc_offset_show, NULL);
1345 
1346 static struct device_attribute *etr_port_attributes[] = {
1347         &dev_attr_online,
1348         &dev_attr_stepping_control,
1349         &dev_attr_state_code,
1350         &dev_attr_untuned,
1351         &dev_attr_network,
1352         &dev_attr_id,
1353         &dev_attr_port,
1354         &dev_attr_coupled,
1355         &dev_attr_local_time,
1356         &dev_attr_utc_offset,
1357         NULL
1358 };
1359 
1360 static int __init etr_register_port(struct device *dev)
1361 {
1362         struct device_attribute **attr;
1363         int rc;
1364 
1365         rc = device_register(dev);
1366         if (rc)
1367                 goto out;
1368         for (attr = etr_port_attributes; *attr; attr++) {
1369                 rc = device_create_file(dev, *attr);
1370                 if (rc)
1371                         goto out_unreg;
1372         }
1373         return 0;
1374 out_unreg:
1375         for (; attr >= etr_port_attributes; attr--)
1376                 device_remove_file(dev, *attr);
1377         device_unregister(dev);
1378 out:
1379         return rc;
1380 }
1381 
1382 static void __init etr_unregister_port(struct device *dev)
1383 {
1384         struct device_attribute **attr;
1385 
1386         for (attr = etr_port_attributes; *attr; attr++)
1387                 device_remove_file(dev, *attr);
1388         device_unregister(dev);
1389 }
1390 
1391 static int __init etr_init_sysfs(void)
1392 {
1393         int rc;
1394 
1395         rc = subsys_system_register(&etr_subsys, NULL);
1396         if (rc)
1397                 goto out;
1398         rc = device_create_file(etr_subsys.dev_root, &dev_attr_stepping_port);
1399         if (rc)
1400                 goto out_unreg_subsys;
1401         rc = device_create_file(etr_subsys.dev_root, &dev_attr_stepping_mode);
1402         if (rc)
1403                 goto out_remove_stepping_port;
1404         rc = etr_register_port(&etr_port0_dev);
1405         if (rc)
1406                 goto out_remove_stepping_mode;
1407         rc = etr_register_port(&etr_port1_dev);
1408         if (rc)
1409                 goto out_remove_port0;
1410         return 0;
1411 
1412 out_remove_port0:
1413         etr_unregister_port(&etr_port0_dev);
1414 out_remove_stepping_mode:
1415         device_remove_file(etr_subsys.dev_root, &dev_attr_stepping_mode);
1416 out_remove_stepping_port:
1417         device_remove_file(etr_subsys.dev_root, &dev_attr_stepping_port);
1418 out_unreg_subsys:
1419         bus_unregister(&etr_subsys);
1420 out:
1421         return rc;
1422 }
1423 
1424 device_initcall(etr_init_sysfs);
1425 
1426 /*
1427  * Server Time Protocol (STP) code.
1428  */
1429 static int stp_online;
1430 static struct stp_sstpi stp_info;
1431 static void *stp_page;
1432 
1433 static void stp_work_fn(struct work_struct *work);
1434 static DEFINE_MUTEX(stp_work_mutex);
1435 static DECLARE_WORK(stp_work, stp_work_fn);
1436 static struct timer_list stp_timer;
1437 
1438 static int __init early_parse_stp(char *p)
1439 {
1440         if (strncmp(p, "off", 3) == 0)
1441                 stp_online = 0;
1442         else if (strncmp(p, "on", 2) == 0)
1443                 stp_online = 1;
1444         return 0;
1445 }
1446 early_param("stp", early_parse_stp);
1447 
1448 /*
1449  * Reset STP attachment.
1450  */
1451 static void __init stp_reset(void)
1452 {
1453         int rc;
1454 
1455         stp_page = (void *) get_zeroed_page(GFP_ATOMIC);
1456         rc = chsc_sstpc(stp_page, STP_OP_CTRL, 0x0000);
1457         if (rc == 0)
1458                 set_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags);
1459         else if (stp_online) {
1460                 pr_warning("The real or virtual hardware system does "
1461                            "not provide an STP interface\n");
1462                 free_page((unsigned long) stp_page);
1463                 stp_page = NULL;
1464                 stp_online = 0;
1465         }
1466 }
1467 
1468 static void stp_timeout(unsigned long dummy)
1469 {
1470         queue_work(time_sync_wq, &stp_work);
1471 }
1472 
1473 static int __init stp_init(void)
1474 {
1475         if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
1476                 return 0;
1477         setup_timer(&stp_timer, stp_timeout, 0UL);
1478         time_init_wq();
1479         if (!stp_online)
1480                 return 0;
1481         queue_work(time_sync_wq, &stp_work);
1482         return 0;
1483 }
1484 
1485 arch_initcall(stp_init);
1486 
1487 /*
1488  * STP timing alert. There are three causes:
1489  * 1) timing status change
1490  * 2) link availability change
1491  * 3) time control parameter change
1492  * In all three cases we are only interested in the clock source state.
1493  * If a STP clock source is now available use it.
1494  */
1495 static void stp_timing_alert(struct stp_irq_parm *intparm)
1496 {
1497         if (intparm->tsc || intparm->lac || intparm->tcpc)
1498                 queue_work(time_sync_wq, &stp_work);
1499 }
1500 
1501 /*
1502  * STP sync check machine check. This is called when the timing state
1503  * changes from the synchronized state to the unsynchronized state.
1504  * After a STP sync check the clock is not in sync. The machine check
1505  * is broadcasted to all cpus at the same time.
1506  */
1507 void stp_sync_check(void)
1508 {
1509         disable_sync_clock(NULL);
1510         queue_work(time_sync_wq, &stp_work);
1511 }
1512 
1513 /*
1514  * STP island condition machine check. This is called when an attached
1515  * server  attempts to communicate over an STP link and the servers
1516  * have matching CTN ids and have a valid stratum-1 configuration
1517  * but the configurations do not match.
1518  */
1519 void stp_island_check(void)
1520 {
1521         disable_sync_clock(NULL);
1522         queue_work(time_sync_wq, &stp_work);
1523 }
1524 
1525 
1526 static int stp_sync_clock(void *data)
1527 {
1528         static int first;
1529         unsigned long long old_clock, delta;
1530         struct clock_sync_data *stp_sync;
1531         int rc;
1532 
1533         stp_sync = data;
1534 
1535         if (xchg(&first, 1) == 1) {
1536                 /* Slave */
1537                 clock_sync_cpu(stp_sync);
1538                 return 0;
1539         }
1540 
1541         /* Wait until all other cpus entered the sync function. */
1542         while (atomic_read(&stp_sync->cpus) != 0)
1543                 cpu_relax();
1544 
1545         enable_sync_clock();
1546 
1547         rc = 0;
1548         if (stp_info.todoff[0] || stp_info.todoff[1] ||
1549             stp_info.todoff[2] || stp_info.todoff[3] ||
1550             stp_info.tmd != 2) {
1551                 old_clock = get_tod_clock();
1552                 rc = chsc_sstpc(stp_page, STP_OP_SYNC, 0);
1553                 if (rc == 0) {
1554                         delta = adjust_time(old_clock, get_tod_clock(), 0);
1555                         fixup_clock_comparator(delta);
1556                         rc = chsc_sstpi(stp_page, &stp_info,
1557                                         sizeof(struct stp_sstpi));
1558                         if (rc == 0 && stp_info.tmd != 2)
1559                                 rc = -EAGAIN;
1560                 }
1561         }
1562         if (rc) {
1563                 disable_sync_clock(NULL);
1564                 stp_sync->in_sync = -EAGAIN;
1565         } else
1566                 stp_sync->in_sync = 1;
1567         xchg(&first, 0);
1568         return 0;
1569 }
1570 
1571 /*
1572  * STP work. Check for the STP state and take over the clock
1573  * synchronization if the STP clock source is usable.
1574  */
1575 static void stp_work_fn(struct work_struct *work)
1576 {
1577         struct clock_sync_data stp_sync;
1578         int rc;
1579 
1580         /* prevent multiple execution. */
1581         mutex_lock(&stp_work_mutex);
1582 
1583         if (!stp_online) {
1584                 chsc_sstpc(stp_page, STP_OP_CTRL, 0x0000);
1585                 del_timer_sync(&stp_timer);
1586                 goto out_unlock;
1587         }
1588 
1589         rc = chsc_sstpc(stp_page, STP_OP_CTRL, 0xb0e0);
1590         if (rc)
1591                 goto out_unlock;
1592 
1593         rc = chsc_sstpi(stp_page, &stp_info, sizeof(struct stp_sstpi));
1594         if (rc || stp_info.c == 0)
1595                 goto out_unlock;
1596 
1597         /* Skip synchronization if the clock is already in sync. */
1598         if (check_sync_clock())
1599                 goto out_unlock;
1600 
1601         memset(&stp_sync, 0, sizeof(stp_sync));
1602         get_online_cpus();
1603         atomic_set(&stp_sync.cpus, num_online_cpus() - 1);
1604         stop_machine(stp_sync_clock, &stp_sync, cpu_online_mask);
1605         put_online_cpus();
1606 
1607         if (!check_sync_clock())
1608                 /*
1609                  * There is a usable clock but the synchonization failed.
1610                  * Retry after a second.
1611                  */
1612                 mod_timer(&stp_timer, jiffies + HZ);
1613 
1614 out_unlock:
1615         mutex_unlock(&stp_work_mutex);
1616 }
1617 
1618 /*
1619  * STP subsys sysfs interface functions
1620  */
1621 static struct bus_type stp_subsys = {
1622         .name           = "stp",
1623         .dev_name       = "stp",
1624 };
1625 
1626 static ssize_t stp_ctn_id_show(struct device *dev,
1627                                 struct device_attribute *attr,
1628                                 char *buf)
1629 {
1630         if (!stp_online)
1631                 return -ENODATA;
1632         return sprintf(buf, "%016llx\n",
1633                        *(unsigned long long *) stp_info.ctnid);
1634 }
1635 
1636 static DEVICE_ATTR(ctn_id, 0400, stp_ctn_id_show, NULL);
1637 
1638 static ssize_t stp_ctn_type_show(struct device *dev,
1639                                 struct device_attribute *attr,
1640                                 char *buf)
1641 {
1642         if (!stp_online)
1643                 return -ENODATA;
1644         return sprintf(buf, "%i\n", stp_info.ctn);
1645 }
1646 
1647 static DEVICE_ATTR(ctn_type, 0400, stp_ctn_type_show, NULL);
1648 
1649 static ssize_t stp_dst_offset_show(struct device *dev,
1650                                    struct device_attribute *attr,
1651                                    char *buf)
1652 {
1653         if (!stp_online || !(stp_info.vbits & 0x2000))
1654                 return -ENODATA;
1655         return sprintf(buf, "%i\n", (int)(s16) stp_info.dsto);
1656 }
1657 
1658 static DEVICE_ATTR(dst_offset, 0400, stp_dst_offset_show, NULL);
1659 
1660 static ssize_t stp_leap_seconds_show(struct device *dev,
1661                                         struct device_attribute *attr,
1662                                         char *buf)
1663 {
1664         if (!stp_online || !(stp_info.vbits & 0x8000))
1665                 return -ENODATA;
1666         return sprintf(buf, "%i\n", (int)(s16) stp_info.leaps);
1667 }
1668 
1669 static DEVICE_ATTR(leap_seconds, 0400, stp_leap_seconds_show, NULL);
1670 
1671 static ssize_t stp_stratum_show(struct device *dev,
1672                                 struct device_attribute *attr,
1673                                 char *buf)
1674 {
1675         if (!stp_online)
1676                 return -ENODATA;
1677         return sprintf(buf, "%i\n", (int)(s16) stp_info.stratum);
1678 }
1679 
1680 static DEVICE_ATTR(stratum, 0400, stp_stratum_show, NULL);
1681 
1682 static ssize_t stp_time_offset_show(struct device *dev,
1683                                 struct device_attribute *attr,
1684                                 char *buf)
1685 {
1686         if (!stp_online || !(stp_info.vbits & 0x0800))
1687                 return -ENODATA;
1688         return sprintf(buf, "%i\n", (int) stp_info.tto);
1689 }
1690 
1691 static DEVICE_ATTR(time_offset, 0400, stp_time_offset_show, NULL);
1692 
1693 static ssize_t stp_time_zone_offset_show(struct device *dev,
1694                                 struct device_attribute *attr,
1695                                 char *buf)
1696 {
1697         if (!stp_online || !(stp_info.vbits & 0x4000))
1698                 return -ENODATA;
1699         return sprintf(buf, "%i\n", (int)(s16) stp_info.tzo);
1700 }
1701 
1702 static DEVICE_ATTR(time_zone_offset, 0400,
1703                          stp_time_zone_offset_show, NULL);
1704 
1705 static ssize_t stp_timing_mode_show(struct device *dev,
1706                                 struct device_attribute *attr,
1707                                 char *buf)
1708 {
1709         if (!stp_online)
1710                 return -ENODATA;
1711         return sprintf(buf, "%i\n", stp_info.tmd);
1712 }
1713 
1714 static DEVICE_ATTR(timing_mode, 0400, stp_timing_mode_show, NULL);
1715 
1716 static ssize_t stp_timing_state_show(struct device *dev,
1717                                 struct device_attribute *attr,
1718                                 char *buf)
1719 {
1720         if (!stp_online)
1721                 return -ENODATA;
1722         return sprintf(buf, "%i\n", stp_info.tst);
1723 }
1724 
1725 static DEVICE_ATTR(timing_state, 0400, stp_timing_state_show, NULL);
1726 
1727 static ssize_t stp_online_show(struct device *dev,
1728                                 struct device_attribute *attr,
1729                                 char *buf)
1730 {
1731         return sprintf(buf, "%i\n", stp_online);
1732 }
1733 
1734 static ssize_t stp_online_store(struct device *dev,
1735                                 struct device_attribute *attr,
1736                                 const char *buf, size_t count)
1737 {
1738         unsigned int value;
1739 
1740         value = simple_strtoul(buf, NULL, 0);
1741         if (value != 0 && value != 1)
1742                 return -EINVAL;
1743         if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
1744                 return -EOPNOTSUPP;
1745         mutex_lock(&clock_sync_mutex);
1746         stp_online = value;
1747         if (stp_online)
1748                 set_bit(CLOCK_SYNC_STP, &clock_sync_flags);
1749         else
1750                 clear_bit(CLOCK_SYNC_STP, &clock_sync_flags);
1751         queue_work(time_sync_wq, &stp_work);
1752         mutex_unlock(&clock_sync_mutex);
1753         return count;
1754 }
1755 
1756 /*
1757  * Can't use DEVICE_ATTR because the attribute should be named
1758  * stp/online but dev_attr_online already exists in this file ..
1759  */
1760 static struct device_attribute dev_attr_stp_online = {
1761         .attr = { .name = "online", .mode = 0600 },
1762         .show   = stp_online_show,
1763         .store  = stp_online_store,
1764 };
1765 
1766 static struct device_attribute *stp_attributes[] = {
1767         &dev_attr_ctn_id,
1768         &dev_attr_ctn_type,
1769         &dev_attr_dst_offset,
1770         &dev_attr_leap_seconds,
1771         &dev_attr_stp_online,
1772         &dev_attr_stratum,
1773         &dev_attr_time_offset,
1774         &dev_attr_time_zone_offset,
1775         &dev_attr_timing_mode,
1776         &dev_attr_timing_state,
1777         NULL
1778 };
1779 
1780 static int __init stp_init_sysfs(void)
1781 {
1782         struct device_attribute **attr;
1783         int rc;
1784 
1785         rc = subsys_system_register(&stp_subsys, NULL);
1786         if (rc)
1787                 goto out;
1788         for (attr = stp_attributes; *attr; attr++) {
1789                 rc = device_create_file(stp_subsys.dev_root, *attr);
1790                 if (rc)
1791                         goto out_unreg;
1792         }
1793         return 0;
1794 out_unreg:
1795         for (; attr >= stp_attributes; attr--)
1796                 device_remove_file(stp_subsys.dev_root, *attr);
1797         bus_unregister(&stp_subsys);
1798 out:
1799         return rc;
1800 }
1801 
1802 device_initcall(stp_init_sysfs);
1803 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp