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

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

Version: ~ [ linux-5.13-rc5 ] ~ [ linux-5.12.9 ] ~ [ linux-5.11.22 ] ~ [ linux-5.10.42 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.124 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.193 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.235 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.271 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.271 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.18.140 ] ~ [ linux-3.16.85 ] ~ [ linux-3.14.79 ] ~ [ linux-3.12.74 ] ~ [ 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 ATOMIC_NOTIFIER_HEAD(s390_epoch_delta_notifier);
 62 EXPORT_SYMBOL(s390_epoch_delta_notifier);
 63 
 64 /*
 65  * Scheduler clock - returns current time in nanosec units.
 66  */
 67 unsigned long long notrace sched_clock(void)
 68 {
 69         return tod_to_ns(get_tod_clock_monotonic());
 70 }
 71 NOKPROBE_SYMBOL(sched_clock);
 72 
 73 /*
 74  * Monotonic_clock - returns # of nanoseconds passed since time_init()
 75  */
 76 unsigned long long monotonic_clock(void)
 77 {
 78         return sched_clock();
 79 }
 80 EXPORT_SYMBOL(monotonic_clock);
 81 
 82 void tod_to_timeval(__u64 todval, struct timespec64 *xt)
 83 {
 84         unsigned long long sec;
 85 
 86         sec = todval >> 12;
 87         do_div(sec, 1000000);
 88         xt->tv_sec = sec;
 89         todval -= (sec * 1000000) << 12;
 90         xt->tv_nsec = ((todval * 1000) >> 12);
 91 }
 92 EXPORT_SYMBOL(tod_to_timeval);
 93 
 94 void clock_comparator_work(void)
 95 {
 96         struct clock_event_device *cd;
 97 
 98         S390_lowcore.clock_comparator = -1ULL;
 99         cd = this_cpu_ptr(&comparators);
100         cd->event_handler(cd);
101 }
102 
103 /*
104  * Fixup the clock comparator.
105  */
106 static void fixup_clock_comparator(unsigned long long delta)
107 {
108         /* If nobody is waiting there's nothing to fix. */
109         if (S390_lowcore.clock_comparator == -1ULL)
110                 return;
111         S390_lowcore.clock_comparator += delta;
112         set_clock_comparator(S390_lowcore.clock_comparator);
113 }
114 
115 static int s390_next_event(unsigned long delta,
116                            struct clock_event_device *evt)
117 {
118         S390_lowcore.clock_comparator = get_tod_clock() + delta;
119         set_clock_comparator(S390_lowcore.clock_comparator);
120         return 0;
121 }
122 
123 /*
124  * Set up lowcore and control register of the current cpu to
125  * enable TOD clock and clock comparator interrupts.
126  */
127 void init_cpu_timer(void)
128 {
129         struct clock_event_device *cd;
130         int cpu;
131 
132         S390_lowcore.clock_comparator = -1ULL;
133         set_clock_comparator(S390_lowcore.clock_comparator);
134 
135         cpu = smp_processor_id();
136         cd = &per_cpu(comparators, cpu);
137         cd->name                = "comparator";
138         cd->features            = CLOCK_EVT_FEAT_ONESHOT;
139         cd->mult                = 16777;
140         cd->shift               = 12;
141         cd->min_delta_ns        = 1;
142         cd->max_delta_ns        = LONG_MAX;
143         cd->rating              = 400;
144         cd->cpumask             = cpumask_of(cpu);
145         cd->set_next_event      = s390_next_event;
146 
147         clockevents_register_device(cd);
148 
149         /* Enable clock comparator timer interrupt. */
150         __ctl_set_bit(0,11);
151 
152         /* Always allow the timing alert external interrupt. */
153         __ctl_set_bit(0, 4);
154 }
155 
156 static void clock_comparator_interrupt(struct ext_code ext_code,
157                                        unsigned int param32,
158                                        unsigned long param64)
159 {
160         inc_irq_stat(IRQEXT_CLK);
161         if (S390_lowcore.clock_comparator == -1ULL)
162                 set_clock_comparator(S390_lowcore.clock_comparator);
163 }
164 
165 static void etr_timing_alert(struct etr_irq_parm *);
166 static void stp_timing_alert(struct stp_irq_parm *);
167 
168 static void timing_alert_interrupt(struct ext_code ext_code,
169                                    unsigned int param32, unsigned long param64)
170 {
171         inc_irq_stat(IRQEXT_TLA);
172         if (param32 & 0x00c40000)
173                 etr_timing_alert((struct etr_irq_parm *) &param32);
174         if (param32 & 0x00038000)
175                 stp_timing_alert((struct stp_irq_parm *) &param32);
176 }
177 
178 static void etr_reset(void);
179 static void stp_reset(void);
180 
181 void read_persistent_clock64(struct timespec64 *ts)
182 {
183         tod_to_timeval(get_tod_clock() - TOD_UNIX_EPOCH, ts);
184 }
185 
186 void read_boot_clock64(struct timespec64 *ts)
187 {
188         tod_to_timeval(sched_clock_base_cc - TOD_UNIX_EPOCH, ts);
189 }
190 
191 static cycle_t read_tod_clock(struct clocksource *cs)
192 {
193         return get_tod_clock();
194 }
195 
196 static struct clocksource clocksource_tod = {
197         .name           = "tod",
198         .rating         = 400,
199         .read           = read_tod_clock,
200         .mask           = -1ULL,
201         .mult           = 1000,
202         .shift          = 12,
203         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
204 };
205 
206 struct clocksource * __init clocksource_default_clock(void)
207 {
208         return &clocksource_tod;
209 }
210 
211 void update_vsyscall(struct timekeeper *tk)
212 {
213         u64 nsecps;
214 
215         if (tk->tkr_mono.clock != &clocksource_tod)
216                 return;
217 
218         /* Make userspace gettimeofday spin until we're done. */
219         ++vdso_data->tb_update_count;
220         smp_wmb();
221         vdso_data->xtime_tod_stamp = tk->tkr_mono.cycle_last;
222         vdso_data->xtime_clock_sec = tk->xtime_sec;
223         vdso_data->xtime_clock_nsec = tk->tkr_mono.xtime_nsec;
224         vdso_data->wtom_clock_sec =
225                 tk->xtime_sec + tk->wall_to_monotonic.tv_sec;
226         vdso_data->wtom_clock_nsec = tk->tkr_mono.xtime_nsec +
227                 + ((u64) tk->wall_to_monotonic.tv_nsec << tk->tkr_mono.shift);
228         nsecps = (u64) NSEC_PER_SEC << tk->tkr_mono.shift;
229         while (vdso_data->wtom_clock_nsec >= nsecps) {
230                 vdso_data->wtom_clock_nsec -= nsecps;
231                 vdso_data->wtom_clock_sec++;
232         }
233 
234         vdso_data->xtime_coarse_sec = tk->xtime_sec;
235         vdso_data->xtime_coarse_nsec =
236                 (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
237         vdso_data->wtom_coarse_sec =
238                 vdso_data->xtime_coarse_sec + tk->wall_to_monotonic.tv_sec;
239         vdso_data->wtom_coarse_nsec =
240                 vdso_data->xtime_coarse_nsec + tk->wall_to_monotonic.tv_nsec;
241         while (vdso_data->wtom_coarse_nsec >= NSEC_PER_SEC) {
242                 vdso_data->wtom_coarse_nsec -= NSEC_PER_SEC;
243                 vdso_data->wtom_coarse_sec++;
244         }
245 
246         vdso_data->tk_mult = tk->tkr_mono.mult;
247         vdso_data->tk_shift = tk->tkr_mono.shift;
248         smp_wmb();
249         ++vdso_data->tb_update_count;
250 }
251 
252 extern struct timezone sys_tz;
253 
254 void update_vsyscall_tz(void)
255 {
256         /* Make userspace gettimeofday spin until we're done. */
257         ++vdso_data->tb_update_count;
258         smp_wmb();
259         vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
260         vdso_data->tz_dsttime = sys_tz.tz_dsttime;
261         smp_wmb();
262         ++vdso_data->tb_update_count;
263 }
264 
265 /*
266  * Initialize the TOD clock and the CPU timer of
267  * the boot cpu.
268  */
269 void __init time_init(void)
270 {
271         /* Reset time synchronization interfaces. */
272         etr_reset();
273         stp_reset();
274 
275         /* request the clock comparator external interrupt */
276         if (register_external_irq(EXT_IRQ_CLK_COMP, clock_comparator_interrupt))
277                 panic("Couldn't request external interrupt 0x1004");
278 
279         /* request the timing alert external interrupt */
280         if (register_external_irq(EXT_IRQ_TIMING_ALERT, timing_alert_interrupt))
281                 panic("Couldn't request external interrupt 0x1406");
282 
283         if (__clocksource_register(&clocksource_tod) != 0)
284                 panic("Could not register TOD clock source");
285 
286         /* Enable TOD clock interrupts on the boot cpu. */
287         init_cpu_timer();
288 
289         /* Enable cpu timer interrupts on the boot cpu. */
290         vtime_init();
291 }
292 
293 /*
294  * The time is "clock". old is what we think the time is.
295  * Adjust the value by a multiple of jiffies and add the delta to ntp.
296  * "delay" is an approximation how long the synchronization took. If
297  * the time correction is positive, then "delay" is subtracted from
298  * the time difference and only the remaining part is passed to ntp.
299  */
300 static unsigned long long adjust_time(unsigned long long old,
301                                       unsigned long long clock,
302                                       unsigned long long delay)
303 {
304         unsigned long long delta, ticks;
305         struct timex adjust;
306 
307         if (clock > old) {
308                 /* It is later than we thought. */
309                 delta = ticks = clock - old;
310                 delta = ticks = (delta < delay) ? 0 : delta - delay;
311                 delta -= do_div(ticks, CLK_TICKS_PER_JIFFY);
312                 adjust.offset = ticks * (1000000 / HZ);
313         } else {
314                 /* It is earlier than we thought. */
315                 delta = ticks = old - clock;
316                 delta -= do_div(ticks, CLK_TICKS_PER_JIFFY);
317                 delta = -delta;
318                 adjust.offset = -ticks * (1000000 / HZ);
319         }
320         sched_clock_base_cc += delta;
321         if (adjust.offset != 0) {
322                 pr_notice("The ETR interface has adjusted the clock "
323                           "by %li microseconds\n", adjust.offset);
324                 adjust.modes = ADJ_OFFSET_SINGLESHOT;
325                 do_adjtimex(&adjust);
326         }
327         return delta;
328 }
329 
330 static DEFINE_PER_CPU(atomic_t, clock_sync_word);
331 static DEFINE_MUTEX(clock_sync_mutex);
332 static unsigned long clock_sync_flags;
333 
334 #define CLOCK_SYNC_HAS_ETR      0
335 #define CLOCK_SYNC_HAS_STP      1
336 #define CLOCK_SYNC_ETR          2
337 #define CLOCK_SYNC_STP          3
338 
339 /*
340  * The synchronous get_clock function. It will write the current clock
341  * value to the clock pointer and return 0 if the clock is in sync with
342  * the external time source. If the clock mode is local it will return
343  * -EOPNOTSUPP and -EAGAIN if the clock is not in sync with the external
344  * reference.
345  */
346 int get_sync_clock(unsigned long long *clock)
347 {
348         atomic_t *sw_ptr;
349         unsigned int sw0, sw1;
350 
351         sw_ptr = &get_cpu_var(clock_sync_word);
352         sw0 = atomic_read(sw_ptr);
353         *clock = get_tod_clock();
354         sw1 = atomic_read(sw_ptr);
355         put_cpu_var(clock_sync_word);
356         if (sw0 == sw1 && (sw0 & 0x80000000U))
357                 /* Success: time is in sync. */
358                 return 0;
359         if (!test_bit(CLOCK_SYNC_HAS_ETR, &clock_sync_flags) &&
360             !test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
361                 return -EOPNOTSUPP;
362         if (!test_bit(CLOCK_SYNC_ETR, &clock_sync_flags) &&
363             !test_bit(CLOCK_SYNC_STP, &clock_sync_flags))
364                 return -EACCES;
365         return -EAGAIN;
366 }
367 EXPORT_SYMBOL(get_sync_clock);
368 
369 /*
370  * Make get_sync_clock return -EAGAIN.
371  */
372 static void disable_sync_clock(void *dummy)
373 {
374         atomic_t *sw_ptr = this_cpu_ptr(&clock_sync_word);
375         /*
376          * Clear the in-sync bit 2^31. All get_sync_clock calls will
377          * fail until the sync bit is turned back on. In addition
378          * increase the "sequence" counter to avoid the race of an
379          * etr event and the complete recovery against get_sync_clock.
380          */
381         atomic_andnot(0x80000000, sw_ptr);
382         atomic_inc(sw_ptr);
383 }
384 
385 /*
386  * Make get_sync_clock return 0 again.
387  * Needs to be called from a context disabled for preemption.
388  */
389 static void enable_sync_clock(void)
390 {
391         atomic_t *sw_ptr = this_cpu_ptr(&clock_sync_word);
392         atomic_or(0x80000000, sw_ptr);
393 }
394 
395 /*
396  * Function to check if the clock is in sync.
397  */
398 static inline int check_sync_clock(void)
399 {
400         atomic_t *sw_ptr;
401         int rc;
402 
403         sw_ptr = &get_cpu_var(clock_sync_word);
404         rc = (atomic_read(sw_ptr) & 0x80000000U) != 0;
405         put_cpu_var(clock_sync_word);
406         return rc;
407 }
408 
409 /* Single threaded workqueue used for etr and stp sync events */
410 static struct workqueue_struct *time_sync_wq;
411 
412 static void __init time_init_wq(void)
413 {
414         if (time_sync_wq)
415                 return;
416         time_sync_wq = create_singlethread_workqueue("timesync");
417 }
418 
419 /*
420  * External Time Reference (ETR) code.
421  */
422 static int etr_port0_online;
423 static int etr_port1_online;
424 static int etr_steai_available;
425 
426 static int __init early_parse_etr(char *p)
427 {
428         if (strncmp(p, "off", 3) == 0)
429                 etr_port0_online = etr_port1_online = 0;
430         else if (strncmp(p, "port0", 5) == 0)
431                 etr_port0_online = 1;
432         else if (strncmp(p, "port1", 5) == 0)
433                 etr_port1_online = 1;
434         else if (strncmp(p, "on", 2) == 0)
435                 etr_port0_online = etr_port1_online = 1;
436         return 0;
437 }
438 early_param("etr", early_parse_etr);
439 
440 enum etr_event {
441         ETR_EVENT_PORT0_CHANGE,
442         ETR_EVENT_PORT1_CHANGE,
443         ETR_EVENT_PORT_ALERT,
444         ETR_EVENT_SYNC_CHECK,
445         ETR_EVENT_SWITCH_LOCAL,
446         ETR_EVENT_UPDATE,
447 };
448 
449 /*
450  * Valid bit combinations of the eacr register are (x = don't care):
451  * e0 e1 dp p0 p1 ea es sl
452  *  0  0  x  0  0  0  0  0  initial, disabled state
453  *  0  0  x  0  1  1  0  0  port 1 online
454  *  0  0  x  1  0  1  0  0  port 0 online
455  *  0  0  x  1  1  1  0  0  both ports online
456  *  0  1  x  0  1  1  0  0  port 1 online and usable, ETR or PPS mode
457  *  0  1  x  0  1  1  0  1  port 1 online, usable and ETR mode
458  *  0  1  x  0  1  1  1  0  port 1 online, usable, PPS mode, in-sync
459  *  0  1  x  0  1  1  1  1  port 1 online, usable, ETR mode, in-sync
460  *  0  1  x  1  1  1  0  0  both ports online, port 1 usable
461  *  0  1  x  1  1  1  1  0  both ports online, port 1 usable, PPS mode, in-sync
462  *  0  1  x  1  1  1  1  1  both ports online, port 1 usable, ETR mode, in-sync
463  *  1  0  x  1  0  1  0  0  port 0 online and usable, ETR or PPS mode
464  *  1  0  x  1  0  1  0  1  port 0 online, usable and ETR mode
465  *  1  0  x  1  0  1  1  0  port 0 online, usable, PPS mode, in-sync
466  *  1  0  x  1  0  1  1  1  port 0 online, usable, ETR mode, in-sync
467  *  1  0  x  1  1  1  0  0  both ports online, port 0 usable
468  *  1  0  x  1  1  1  1  0  both ports online, port 0 usable, PPS mode, in-sync
469  *  1  0  x  1  1  1  1  1  both ports online, port 0 usable, ETR mode, in-sync
470  *  1  1  x  1  1  1  1  0  both ports online & usable, ETR, in-sync
471  *  1  1  x  1  1  1  1  1  both ports online & usable, ETR, in-sync
472  */
473 static struct etr_eacr etr_eacr;
474 static u64 etr_tolec;                   /* time of last eacr update */
475 static struct etr_aib etr_port0;
476 static int etr_port0_uptodate;
477 static struct etr_aib etr_port1;
478 static int etr_port1_uptodate;
479 static unsigned long etr_events;
480 static struct timer_list etr_timer;
481 
482 static void etr_timeout(unsigned long dummy);
483 static void etr_work_fn(struct work_struct *work);
484 static DEFINE_MUTEX(etr_work_mutex);
485 static DECLARE_WORK(etr_work, etr_work_fn);
486 
487 /*
488  * Reset ETR attachment.
489  */
490 static void etr_reset(void)
491 {
492         etr_eacr =  (struct etr_eacr) {
493                 .e0 = 0, .e1 = 0, ._pad0 = 4, .dp = 0,
494                 .p0 = 0, .p1 = 0, ._pad1 = 0, .ea = 0,
495                 .es = 0, .sl = 0 };
496         if (etr_setr(&etr_eacr) == 0) {
497                 etr_tolec = get_tod_clock();
498                 set_bit(CLOCK_SYNC_HAS_ETR, &clock_sync_flags);
499                 if (etr_port0_online && etr_port1_online)
500                         set_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
501         } else if (etr_port0_online || etr_port1_online) {
502                 pr_warning("The real or virtual hardware system does "
503                            "not provide an ETR interface\n");
504                 etr_port0_online = etr_port1_online = 0;
505         }
506 }
507 
508 static int __init etr_init(void)
509 {
510         struct etr_aib aib;
511 
512         if (!test_bit(CLOCK_SYNC_HAS_ETR, &clock_sync_flags))
513                 return 0;
514         time_init_wq();
515         /* Check if this machine has the steai instruction. */
516         if (etr_steai(&aib, ETR_STEAI_STEPPING_PORT) == 0)
517                 etr_steai_available = 1;
518         setup_timer(&etr_timer, etr_timeout, 0UL);
519         if (etr_port0_online) {
520                 set_bit(ETR_EVENT_PORT0_CHANGE, &etr_events);
521                 queue_work(time_sync_wq, &etr_work);
522         }
523         if (etr_port1_online) {
524                 set_bit(ETR_EVENT_PORT1_CHANGE, &etr_events);
525                 queue_work(time_sync_wq, &etr_work);
526         }
527         return 0;
528 }
529 
530 arch_initcall(etr_init);
531 
532 /*
533  * Two sorts of ETR machine checks. The architecture reads:
534  * "When a machine-check niterruption occurs and if a switch-to-local or
535  *  ETR-sync-check interrupt request is pending but disabled, this pending
536  *  disabled interruption request is indicated and is cleared".
537  * Which means that we can get etr_switch_to_local events from the machine
538  * check handler although the interruption condition is disabled. Lovely..
539  */
540 
541 /*
542  * Switch to local machine check. This is called when the last usable
543  * ETR port goes inactive. After switch to local the clock is not in sync.
544  */
545 int etr_switch_to_local(void)
546 {
547         if (!etr_eacr.sl)
548                 return 0;
549         disable_sync_clock(NULL);
550         if (!test_and_set_bit(ETR_EVENT_SWITCH_LOCAL, &etr_events)) {
551                 etr_eacr.es = etr_eacr.sl = 0;
552                 etr_setr(&etr_eacr);
553                 return 1;
554         }
555         return 0;
556 }
557 
558 /*
559  * ETR sync check machine check. This is called when the ETR OTE and the
560  * local clock OTE are farther apart than the ETR sync check tolerance.
561  * After a ETR sync check the clock is not in sync. The machine check
562  * is broadcasted to all cpus at the same time.
563  */
564 int etr_sync_check(void)
565 {
566         if (!etr_eacr.es)
567                 return 0;
568         disable_sync_clock(NULL);
569         if (!test_and_set_bit(ETR_EVENT_SYNC_CHECK, &etr_events)) {
570                 etr_eacr.es = 0;
571                 etr_setr(&etr_eacr);
572                 return 1;
573         }
574         return 0;
575 }
576 
577 void etr_queue_work(void)
578 {
579         queue_work(time_sync_wq, &etr_work);
580 }
581 
582 /*
583  * ETR timing alert. There are two causes:
584  * 1) port state change, check the usability of the port
585  * 2) port alert, one of the ETR-data-validity bits (v1-v2 bits of the
586  *    sldr-status word) or ETR-data word 1 (edf1) or ETR-data word 3 (edf3)
587  *    or ETR-data word 4 (edf4) has changed.
588  */
589 static void etr_timing_alert(struct etr_irq_parm *intparm)
590 {
591         if (intparm->pc0)
592                 /* ETR port 0 state change. */
593                 set_bit(ETR_EVENT_PORT0_CHANGE, &etr_events);
594         if (intparm->pc1)
595                 /* ETR port 1 state change. */
596                 set_bit(ETR_EVENT_PORT1_CHANGE, &etr_events);
597         if (intparm->eai)
598                 /*
599                  * ETR port alert on either port 0, 1 or both.
600                  * Both ports are not up-to-date now.
601                  */
602                 set_bit(ETR_EVENT_PORT_ALERT, &etr_events);
603         queue_work(time_sync_wq, &etr_work);
604 }
605 
606 static void etr_timeout(unsigned long dummy)
607 {
608         set_bit(ETR_EVENT_UPDATE, &etr_events);
609         queue_work(time_sync_wq, &etr_work);
610 }
611 
612 /*
613  * Check if the etr mode is pss.
614  */
615 static inline int etr_mode_is_pps(struct etr_eacr eacr)
616 {
617         return eacr.es && !eacr.sl;
618 }
619 
620 /*
621  * Check if the etr mode is etr.
622  */
623 static inline int etr_mode_is_etr(struct etr_eacr eacr)
624 {
625         return eacr.es && eacr.sl;
626 }
627 
628 /*
629  * Check if the port can be used for TOD synchronization.
630  * For PPS mode the port has to receive OTEs. For ETR mode
631  * the port has to receive OTEs, the ETR stepping bit has to
632  * be zero and the validity bits for data frame 1, 2, and 3
633  * have to be 1.
634  */
635 static int etr_port_valid(struct etr_aib *aib, int port)
636 {
637         unsigned int psc;
638 
639         /* Check that this port is receiving OTEs. */
640         if (aib->tsp == 0)
641                 return 0;
642 
643         psc = port ? aib->esw.psc1 : aib->esw.psc0;
644         if (psc == etr_lpsc_pps_mode)
645                 return 1;
646         if (psc == etr_lpsc_operational_step)
647                 return !aib->esw.y && aib->slsw.v1 &&
648                         aib->slsw.v2 && aib->slsw.v3;
649         return 0;
650 }
651 
652 /*
653  * Check if two ports are on the same network.
654  */
655 static int etr_compare_network(struct etr_aib *aib1, struct etr_aib *aib2)
656 {
657         // FIXME: any other fields we have to compare?
658         return aib1->edf1.net_id == aib2->edf1.net_id;
659 }
660 
661 /*
662  * Wrapper for etr_stei that converts physical port states
663  * to logical port states to be consistent with the output
664  * of stetr (see etr_psc vs. etr_lpsc).
665  */
666 static void etr_steai_cv(struct etr_aib *aib, unsigned int func)
667 {
668         BUG_ON(etr_steai(aib, func) != 0);
669         /* Convert port state to logical port state. */
670         if (aib->esw.psc0 == 1)
671                 aib->esw.psc0 = 2;
672         else if (aib->esw.psc0 == 0 && aib->esw.p == 0)
673                 aib->esw.psc0 = 1;
674         if (aib->esw.psc1 == 1)
675                 aib->esw.psc1 = 2;
676         else if (aib->esw.psc1 == 0 && aib->esw.p == 1)
677                 aib->esw.psc1 = 1;
678 }
679 
680 /*
681  * Check if the aib a2 is still connected to the same attachment as
682  * aib a1, the etv values differ by one and a2 is valid.
683  */
684 static int etr_aib_follows(struct etr_aib *a1, struct etr_aib *a2, int p)
685 {
686         int state_a1, state_a2;
687 
688         /* Paranoia check: e0/e1 should better be the same. */
689         if (a1->esw.eacr.e0 != a2->esw.eacr.e0 ||
690             a1->esw.eacr.e1 != a2->esw.eacr.e1)
691                 return 0;
692 
693         /* Still connected to the same etr ? */
694         state_a1 = p ? a1->esw.psc1 : a1->esw.psc0;
695         state_a2 = p ? a2->esw.psc1 : a2->esw.psc0;
696         if (state_a1 == etr_lpsc_operational_step) {
697                 if (state_a2 != etr_lpsc_operational_step ||
698                     a1->edf1.net_id != a2->edf1.net_id ||
699                     a1->edf1.etr_id != a2->edf1.etr_id ||
700                     a1->edf1.etr_pn != a2->edf1.etr_pn)
701                         return 0;
702         } else if (state_a2 != etr_lpsc_pps_mode)
703                 return 0;
704 
705         /* The ETV value of a2 needs to be ETV of a1 + 1. */
706         if (a1->edf2.etv + 1 != a2->edf2.etv)
707                 return 0;
708 
709         if (!etr_port_valid(a2, p))
710                 return 0;
711 
712         return 1;
713 }
714 
715 struct clock_sync_data {
716         atomic_t cpus;
717         int in_sync;
718         unsigned long long fixup_cc;
719         int etr_port;
720         struct etr_aib *etr_aib;
721 };
722 
723 static void clock_sync_cpu(struct clock_sync_data *sync)
724 {
725         atomic_dec(&sync->cpus);
726         enable_sync_clock();
727         /*
728          * This looks like a busy wait loop but it isn't. etr_sync_cpus
729          * is called on all other cpus while the TOD clocks is stopped.
730          * __udelay will stop the cpu on an enabled wait psw until the
731          * TOD is running again.
732          */
733         while (sync->in_sync == 0) {
734                 __udelay(1);
735                 /*
736                  * A different cpu changes *in_sync. Therefore use
737                  * barrier() to force memory access.
738                  */
739                 barrier();
740         }
741         if (sync->in_sync != 1)
742                 /* Didn't work. Clear per-cpu in sync bit again. */
743                 disable_sync_clock(NULL);
744         /*
745          * This round of TOD syncing is done. Set the clock comparator
746          * to the next tick and let the processor continue.
747          */
748         fixup_clock_comparator(sync->fixup_cc);
749 }
750 
751 /*
752  * Sync the TOD clock using the port referred to by aibp. This port
753  * has to be enabled and the other port has to be disabled. The
754  * last eacr update has to be more than 1.6 seconds in the past.
755  */
756 static int etr_sync_clock(void *data)
757 {
758         static int first;
759         unsigned long long clock, old_clock, clock_delta, delay, delta;
760         struct clock_sync_data *etr_sync;
761         struct etr_aib *sync_port, *aib;
762         int port;
763         int rc;
764 
765         etr_sync = data;
766 
767         if (xchg(&first, 1) == 1) {
768                 /* Slave */
769                 clock_sync_cpu(etr_sync);
770                 return 0;
771         }
772 
773         /* Wait until all other cpus entered the sync function. */
774         while (atomic_read(&etr_sync->cpus) != 0)
775                 cpu_relax();
776 
777         port = etr_sync->etr_port;
778         aib = etr_sync->etr_aib;
779         sync_port = (port == 0) ? &etr_port0 : &etr_port1;
780         enable_sync_clock();
781 
782         /* Set clock to next OTE. */
783         __ctl_set_bit(14, 21);
784         __ctl_set_bit(0, 29);
785         clock = ((unsigned long long) (aib->edf2.etv + 1)) << 32;
786         old_clock = get_tod_clock();
787         if (set_tod_clock(clock) == 0) {
788                 __udelay(1);    /* Wait for the clock to start. */
789                 __ctl_clear_bit(0, 29);
790                 __ctl_clear_bit(14, 21);
791                 etr_stetr(aib);
792                 /* Adjust Linux timing variables. */
793                 delay = (unsigned long long)
794                         (aib->edf2.etv - sync_port->edf2.etv) << 32;
795                 delta = adjust_time(old_clock, clock, delay);
796                 clock_delta = clock - old_clock;
797                 atomic_notifier_call_chain(&s390_epoch_delta_notifier, 0,
798                                            &clock_delta);
799                 etr_sync->fixup_cc = delta;
800                 fixup_clock_comparator(delta);
801                 /* Verify that the clock is properly set. */
802                 if (!etr_aib_follows(sync_port, aib, port)) {
803                         /* Didn't work. */
804                         disable_sync_clock(NULL);
805                         etr_sync->in_sync = -EAGAIN;
806                         rc = -EAGAIN;
807                 } else {
808                         etr_sync->in_sync = 1;
809                         rc = 0;
810                 }
811         } else {
812                 /* Could not set the clock ?!? */
813                 __ctl_clear_bit(0, 29);
814                 __ctl_clear_bit(14, 21);
815                 disable_sync_clock(NULL);
816                 etr_sync->in_sync = -EAGAIN;
817                 rc = -EAGAIN;
818         }
819         xchg(&first, 0);
820         return rc;
821 }
822 
823 static int etr_sync_clock_stop(struct etr_aib *aib, int port)
824 {
825         struct clock_sync_data etr_sync;
826         struct etr_aib *sync_port;
827         int follows;
828         int rc;
829 
830         /* Check if the current aib is adjacent to the sync port aib. */
831         sync_port = (port == 0) ? &etr_port0 : &etr_port1;
832         follows = etr_aib_follows(sync_port, aib, port);
833         memcpy(sync_port, aib, sizeof(*aib));
834         if (!follows)
835                 return -EAGAIN;
836         memset(&etr_sync, 0, sizeof(etr_sync));
837         etr_sync.etr_aib = aib;
838         etr_sync.etr_port = port;
839         get_online_cpus();
840         atomic_set(&etr_sync.cpus, num_online_cpus() - 1);
841         rc = stop_machine(etr_sync_clock, &etr_sync, cpu_online_mask);
842         put_online_cpus();
843         return rc;
844 }
845 
846 /*
847  * Handle the immediate effects of the different events.
848  * The port change event is used for online/offline changes.
849  */
850 static struct etr_eacr etr_handle_events(struct etr_eacr eacr)
851 {
852         if (test_and_clear_bit(ETR_EVENT_SYNC_CHECK, &etr_events))
853                 eacr.es = 0;
854         if (test_and_clear_bit(ETR_EVENT_SWITCH_LOCAL, &etr_events))
855                 eacr.es = eacr.sl = 0;
856         if (test_and_clear_bit(ETR_EVENT_PORT_ALERT, &etr_events))
857                 etr_port0_uptodate = etr_port1_uptodate = 0;
858 
859         if (test_and_clear_bit(ETR_EVENT_PORT0_CHANGE, &etr_events)) {
860                 if (eacr.e0)
861                         /*
862                          * Port change of an enabled port. We have to
863                          * assume that this can have caused an stepping
864                          * port switch.
865                          */
866                         etr_tolec = get_tod_clock();
867                 eacr.p0 = etr_port0_online;
868                 if (!eacr.p0)
869                         eacr.e0 = 0;
870                 etr_port0_uptodate = 0;
871         }
872         if (test_and_clear_bit(ETR_EVENT_PORT1_CHANGE, &etr_events)) {
873                 if (eacr.e1)
874                         /*
875                          * Port change of an enabled port. We have to
876                          * assume that this can have caused an stepping
877                          * port switch.
878                          */
879                         etr_tolec = get_tod_clock();
880                 eacr.p1 = etr_port1_online;
881                 if (!eacr.p1)
882                         eacr.e1 = 0;
883                 etr_port1_uptodate = 0;
884         }
885         clear_bit(ETR_EVENT_UPDATE, &etr_events);
886         return eacr;
887 }
888 
889 /*
890  * Set up a timer that expires after the etr_tolec + 1.6 seconds if
891  * one of the ports needs an update.
892  */
893 static void etr_set_tolec_timeout(unsigned long long now)
894 {
895         unsigned long micros;
896 
897         if ((!etr_eacr.p0 || etr_port0_uptodate) &&
898             (!etr_eacr.p1 || etr_port1_uptodate))
899                 return;
900         micros = (now > etr_tolec) ? ((now - etr_tolec) >> 12) : 0;
901         micros = (micros > 1600000) ? 0 : 1600000 - micros;
902         mod_timer(&etr_timer, jiffies + (micros * HZ) / 1000000 + 1);
903 }
904 
905 /*
906  * Set up a time that expires after 1/2 second.
907  */
908 static void etr_set_sync_timeout(void)
909 {
910         mod_timer(&etr_timer, jiffies + HZ/2);
911 }
912 
913 /*
914  * Update the aib information for one or both ports.
915  */
916 static struct etr_eacr etr_handle_update(struct etr_aib *aib,
917                                          struct etr_eacr eacr)
918 {
919         /* With both ports disabled the aib information is useless. */
920         if (!eacr.e0 && !eacr.e1)
921                 return eacr;
922 
923         /* Update port0 or port1 with aib stored in etr_work_fn. */
924         if (aib->esw.q == 0) {
925                 /* Information for port 0 stored. */
926                 if (eacr.p0 && !etr_port0_uptodate) {
927                         etr_port0 = *aib;
928                         if (etr_port0_online)
929                                 etr_port0_uptodate = 1;
930                 }
931         } else {
932                 /* Information for port 1 stored. */
933                 if (eacr.p1 && !etr_port1_uptodate) {
934                         etr_port1 = *aib;
935                         if (etr_port0_online)
936                                 etr_port1_uptodate = 1;
937                 }
938         }
939 
940         /*
941          * Do not try to get the alternate port aib if the clock
942          * is not in sync yet.
943          */
944         if (!eacr.es || !check_sync_clock())
945                 return eacr;
946 
947         /*
948          * If steai is available we can get the information about
949          * the other port immediately. If only stetr is available the
950          * data-port bit toggle has to be used.
951          */
952         if (etr_steai_available) {
953                 if (eacr.p0 && !etr_port0_uptodate) {
954                         etr_steai_cv(&etr_port0, ETR_STEAI_PORT_0);
955                         etr_port0_uptodate = 1;
956                 }
957                 if (eacr.p1 && !etr_port1_uptodate) {
958                         etr_steai_cv(&etr_port1, ETR_STEAI_PORT_1);
959                         etr_port1_uptodate = 1;
960                 }
961         } else {
962                 /*
963                  * One port was updated above, if the other
964                  * port is not uptodate toggle dp bit.
965                  */
966                 if ((eacr.p0 && !etr_port0_uptodate) ||
967                     (eacr.p1 && !etr_port1_uptodate))
968                         eacr.dp ^= 1;
969                 else
970                         eacr.dp = 0;
971         }
972         return eacr;
973 }
974 
975 /*
976  * Write new etr control register if it differs from the current one.
977  * Return 1 if etr_tolec has been updated as well.
978  */
979 static void etr_update_eacr(struct etr_eacr eacr)
980 {
981         int dp_changed;
982 
983         if (memcmp(&etr_eacr, &eacr, sizeof(eacr)) == 0)
984                 /* No change, return. */
985                 return;
986         /*
987          * The disable of an active port of the change of the data port
988          * bit can/will cause a change in the data port.
989          */
990         dp_changed = etr_eacr.e0 > eacr.e0 || etr_eacr.e1 > eacr.e1 ||
991                 (etr_eacr.dp ^ eacr.dp) != 0;
992         etr_eacr = eacr;
993         etr_setr(&etr_eacr);
994         if (dp_changed)
995                 etr_tolec = get_tod_clock();
996 }
997 
998 /*
999  * ETR work. In this function you'll find the main logic. In
1000  * particular this is the only function that calls etr_update_eacr(),
1001  * it "controls" the etr control register.
1002  */
1003 static void etr_work_fn(struct work_struct *work)
1004 {
1005         unsigned long long now;
1006         struct etr_eacr eacr;
1007         struct etr_aib aib;
1008         int sync_port;
1009 
1010         /* prevent multiple execution. */
1011         mutex_lock(&etr_work_mutex);
1012 
1013         /* Create working copy of etr_eacr. */
1014         eacr = etr_eacr;
1015 
1016         /* Check for the different events and their immediate effects. */
1017         eacr = etr_handle_events(eacr);
1018 
1019         /* Check if ETR is supposed to be active. */
1020         eacr.ea = eacr.p0 || eacr.p1;
1021         if (!eacr.ea) {
1022                 /* Both ports offline. Reset everything. */
1023                 eacr.dp = eacr.es = eacr.sl = 0;
1024                 on_each_cpu(disable_sync_clock, NULL, 1);
1025                 del_timer_sync(&etr_timer);
1026                 etr_update_eacr(eacr);
1027                 goto out_unlock;
1028         }
1029 
1030         /* Store aib to get the current ETR status word. */
1031         BUG_ON(etr_stetr(&aib) != 0);
1032         etr_port0.esw = etr_port1.esw = aib.esw;        /* Copy status word. */
1033         now = get_tod_clock();
1034 
1035         /*
1036          * Update the port information if the last stepping port change
1037          * or data port change is older than 1.6 seconds.
1038          */
1039         if (now >= etr_tolec + (1600000 << 12))
1040                 eacr = etr_handle_update(&aib, eacr);
1041 
1042         /*
1043          * Select ports to enable. The preferred synchronization mode is PPS.
1044          * If a port can be enabled depends on a number of things:
1045          * 1) The port needs to be online and uptodate. A port is not
1046          *    disabled just because it is not uptodate, but it is only
1047          *    enabled if it is uptodate.
1048          * 2) The port needs to have the same mode (pps / etr).
1049          * 3) The port needs to be usable -> etr_port_valid() == 1
1050          * 4) To enable the second port the clock needs to be in sync.
1051          * 5) If both ports are useable and are ETR ports, the network id
1052          *    has to be the same.
1053          * The eacr.sl bit is used to indicate etr mode vs. pps mode.
1054          */
1055         if (eacr.p0 && aib.esw.psc0 == etr_lpsc_pps_mode) {
1056                 eacr.sl = 0;
1057                 eacr.e0 = 1;
1058                 if (!etr_mode_is_pps(etr_eacr))
1059                         eacr.es = 0;
1060                 if (!eacr.es || !eacr.p1 || aib.esw.psc1 != etr_lpsc_pps_mode)
1061                         eacr.e1 = 0;
1062                 // FIXME: uptodate checks ?
1063                 else if (etr_port0_uptodate && etr_port1_uptodate)
1064                         eacr.e1 = 1;
1065                 sync_port = (etr_port0_uptodate &&
1066                              etr_port_valid(&etr_port0, 0)) ? 0 : -1;
1067         } else if (eacr.p1 && aib.esw.psc1 == etr_lpsc_pps_mode) {
1068                 eacr.sl = 0;
1069                 eacr.e0 = 0;
1070                 eacr.e1 = 1;
1071                 if (!etr_mode_is_pps(etr_eacr))
1072                         eacr.es = 0;
1073                 sync_port = (etr_port1_uptodate &&
1074                              etr_port_valid(&etr_port1, 1)) ? 1 : -1;
1075         } else if (eacr.p0 && aib.esw.psc0 == etr_lpsc_operational_step) {
1076                 eacr.sl = 1;
1077                 eacr.e0 = 1;
1078                 if (!etr_mode_is_etr(etr_eacr))
1079                         eacr.es = 0;
1080                 if (!eacr.es || !eacr.p1 ||
1081                     aib.esw.psc1 != etr_lpsc_operational_alt)
1082                         eacr.e1 = 0;
1083                 else if (etr_port0_uptodate && etr_port1_uptodate &&
1084                          etr_compare_network(&etr_port0, &etr_port1))
1085                         eacr.e1 = 1;
1086                 sync_port = (etr_port0_uptodate &&
1087                              etr_port_valid(&etr_port0, 0)) ? 0 : -1;
1088         } else if (eacr.p1 && aib.esw.psc1 == etr_lpsc_operational_step) {
1089                 eacr.sl = 1;
1090                 eacr.e0 = 0;
1091                 eacr.e1 = 1;
1092                 if (!etr_mode_is_etr(etr_eacr))
1093                         eacr.es = 0;
1094                 sync_port = (etr_port1_uptodate &&
1095                              etr_port_valid(&etr_port1, 1)) ? 1 : -1;
1096         } else {
1097                 /* Both ports not usable. */
1098                 eacr.es = eacr.sl = 0;
1099                 sync_port = -1;
1100         }
1101 
1102         /*
1103          * If the clock is in sync just update the eacr and return.
1104          * If there is no valid sync port wait for a port update.
1105          */
1106         if ((eacr.es && check_sync_clock()) || sync_port < 0) {
1107                 etr_update_eacr(eacr);
1108                 etr_set_tolec_timeout(now);
1109                 goto out_unlock;
1110         }
1111 
1112         /*
1113          * Prepare control register for clock syncing
1114          * (reset data port bit, set sync check control.
1115          */
1116         eacr.dp = 0;
1117         eacr.es = 1;
1118 
1119         /*
1120          * Update eacr and try to synchronize the clock. If the update
1121          * of eacr caused a stepping port switch (or if we have to
1122          * assume that a stepping port switch has occurred) or the
1123          * clock syncing failed, reset the sync check control bit
1124          * and set up a timer to try again after 0.5 seconds
1125          */
1126         etr_update_eacr(eacr);
1127         if (now < etr_tolec + (1600000 << 12) ||
1128             etr_sync_clock_stop(&aib, sync_port) != 0) {
1129                 /* Sync failed. Try again in 1/2 second. */
1130                 eacr.es = 0;
1131                 etr_update_eacr(eacr);
1132                 etr_set_sync_timeout();
1133         } else
1134                 etr_set_tolec_timeout(now);
1135 out_unlock:
1136         mutex_unlock(&etr_work_mutex);
1137 }
1138 
1139 /*
1140  * Sysfs interface functions
1141  */
1142 static struct bus_type etr_subsys = {
1143         .name           = "etr",
1144         .dev_name       = "etr",
1145 };
1146 
1147 static struct device etr_port0_dev = {
1148         .id     = 0,
1149         .bus    = &etr_subsys,
1150 };
1151 
1152 static struct device etr_port1_dev = {
1153         .id     = 1,
1154         .bus    = &etr_subsys,
1155 };
1156 
1157 /*
1158  * ETR subsys attributes
1159  */
1160 static ssize_t etr_stepping_port_show(struct device *dev,
1161                                         struct device_attribute *attr,
1162                                         char *buf)
1163 {
1164         return sprintf(buf, "%i\n", etr_port0.esw.p);
1165 }
1166 
1167 static DEVICE_ATTR(stepping_port, 0400, etr_stepping_port_show, NULL);
1168 
1169 static ssize_t etr_stepping_mode_show(struct device *dev,
1170                                         struct device_attribute *attr,
1171                                         char *buf)
1172 {
1173         char *mode_str;
1174 
1175         if (etr_mode_is_pps(etr_eacr))
1176                 mode_str = "pps";
1177         else if (etr_mode_is_etr(etr_eacr))
1178                 mode_str = "etr";
1179         else
1180                 mode_str = "local";
1181         return sprintf(buf, "%s\n", mode_str);
1182 }
1183 
1184 static DEVICE_ATTR(stepping_mode, 0400, etr_stepping_mode_show, NULL);
1185 
1186 /*
1187  * ETR port attributes
1188  */
1189 static inline struct etr_aib *etr_aib_from_dev(struct device *dev)
1190 {
1191         if (dev == &etr_port0_dev)
1192                 return etr_port0_online ? &etr_port0 : NULL;
1193         else
1194                 return etr_port1_online ? &etr_port1 : NULL;
1195 }
1196 
1197 static ssize_t etr_online_show(struct device *dev,
1198                                 struct device_attribute *attr,
1199                                 char *buf)
1200 {
1201         unsigned int online;
1202 
1203         online = (dev == &etr_port0_dev) ? etr_port0_online : etr_port1_online;
1204         return sprintf(buf, "%i\n", online);
1205 }
1206 
1207 static ssize_t etr_online_store(struct device *dev,
1208                                 struct device_attribute *attr,
1209                                 const char *buf, size_t count)
1210 {
1211         unsigned int value;
1212 
1213         value = simple_strtoul(buf, NULL, 0);
1214         if (value != 0 && value != 1)
1215                 return -EINVAL;
1216         if (!test_bit(CLOCK_SYNC_HAS_ETR, &clock_sync_flags))
1217                 return -EOPNOTSUPP;
1218         mutex_lock(&clock_sync_mutex);
1219         if (dev == &etr_port0_dev) {
1220                 if (etr_port0_online == value)
1221                         goto out;       /* Nothing to do. */
1222                 etr_port0_online = value;
1223                 if (etr_port0_online && etr_port1_online)
1224                         set_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
1225                 else
1226                         clear_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
1227                 set_bit(ETR_EVENT_PORT0_CHANGE, &etr_events);
1228                 queue_work(time_sync_wq, &etr_work);
1229         } else {
1230                 if (etr_port1_online == value)
1231                         goto out;       /* Nothing to do. */
1232                 etr_port1_online = value;
1233                 if (etr_port0_online && etr_port1_online)
1234                         set_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
1235                 else
1236                         clear_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
1237                 set_bit(ETR_EVENT_PORT1_CHANGE, &etr_events);
1238                 queue_work(time_sync_wq, &etr_work);
1239         }
1240 out:
1241         mutex_unlock(&clock_sync_mutex);
1242         return count;
1243 }
1244 
1245 static DEVICE_ATTR(online, 0600, etr_online_show, etr_online_store);
1246 
1247 static ssize_t etr_stepping_control_show(struct device *dev,
1248                                         struct device_attribute *attr,
1249                                         char *buf)
1250 {
1251         return sprintf(buf, "%i\n", (dev == &etr_port0_dev) ?
1252                        etr_eacr.e0 : etr_eacr.e1);
1253 }
1254 
1255 static DEVICE_ATTR(stepping_control, 0400, etr_stepping_control_show, NULL);
1256 
1257 static ssize_t etr_mode_code_show(struct device *dev,
1258                                 struct device_attribute *attr, char *buf)
1259 {
1260         if (!etr_port0_online && !etr_port1_online)
1261                 /* Status word is not uptodate if both ports are offline. */
1262                 return -ENODATA;
1263         return sprintf(buf, "%i\n", (dev == &etr_port0_dev) ?
1264                        etr_port0.esw.psc0 : etr_port0.esw.psc1);
1265 }
1266 
1267 static DEVICE_ATTR(state_code, 0400, etr_mode_code_show, NULL);
1268 
1269 static ssize_t etr_untuned_show(struct device *dev,
1270                                 struct device_attribute *attr, char *buf)
1271 {
1272         struct etr_aib *aib = etr_aib_from_dev(dev);
1273 
1274         if (!aib || !aib->slsw.v1)
1275                 return -ENODATA;
1276         return sprintf(buf, "%i\n", aib->edf1.u);
1277 }
1278 
1279 static DEVICE_ATTR(untuned, 0400, etr_untuned_show, NULL);
1280 
1281 static ssize_t etr_network_id_show(struct device *dev,
1282                                 struct device_attribute *attr, char *buf)
1283 {
1284         struct etr_aib *aib = etr_aib_from_dev(dev);
1285 
1286         if (!aib || !aib->slsw.v1)
1287                 return -ENODATA;
1288         return sprintf(buf, "%i\n", aib->edf1.net_id);
1289 }
1290 
1291 static DEVICE_ATTR(network, 0400, etr_network_id_show, NULL);
1292 
1293 static ssize_t etr_id_show(struct device *dev,
1294                         struct device_attribute *attr, char *buf)
1295 {
1296         struct etr_aib *aib = etr_aib_from_dev(dev);
1297 
1298         if (!aib || !aib->slsw.v1)
1299                 return -ENODATA;
1300         return sprintf(buf, "%i\n", aib->edf1.etr_id);
1301 }
1302 
1303 static DEVICE_ATTR(id, 0400, etr_id_show, NULL);
1304 
1305 static ssize_t etr_port_number_show(struct device *dev,
1306                         struct device_attribute *attr, char *buf)
1307 {
1308         struct etr_aib *aib = etr_aib_from_dev(dev);
1309 
1310         if (!aib || !aib->slsw.v1)
1311                 return -ENODATA;
1312         return sprintf(buf, "%i\n", aib->edf1.etr_pn);
1313 }
1314 
1315 static DEVICE_ATTR(port, 0400, etr_port_number_show, NULL);
1316 
1317 static ssize_t etr_coupled_show(struct device *dev,
1318                         struct device_attribute *attr, char *buf)
1319 {
1320         struct etr_aib *aib = etr_aib_from_dev(dev);
1321 
1322         if (!aib || !aib->slsw.v3)
1323                 return -ENODATA;
1324         return sprintf(buf, "%i\n", aib->edf3.c);
1325 }
1326 
1327 static DEVICE_ATTR(coupled, 0400, etr_coupled_show, NULL);
1328 
1329 static ssize_t etr_local_time_show(struct device *dev,
1330                         struct device_attribute *attr, char *buf)
1331 {
1332         struct etr_aib *aib = etr_aib_from_dev(dev);
1333 
1334         if (!aib || !aib->slsw.v3)
1335                 return -ENODATA;
1336         return sprintf(buf, "%i\n", aib->edf3.blto);
1337 }
1338 
1339 static DEVICE_ATTR(local_time, 0400, etr_local_time_show, NULL);
1340 
1341 static ssize_t etr_utc_offset_show(struct device *dev,
1342                         struct device_attribute *attr, char *buf)
1343 {
1344         struct etr_aib *aib = etr_aib_from_dev(dev);
1345 
1346         if (!aib || !aib->slsw.v3)
1347                 return -ENODATA;
1348         return sprintf(buf, "%i\n", aib->edf3.buo);
1349 }
1350 
1351 static DEVICE_ATTR(utc_offset, 0400, etr_utc_offset_show, NULL);
1352 
1353 static struct device_attribute *etr_port_attributes[] = {
1354         &dev_attr_online,
1355         &dev_attr_stepping_control,
1356         &dev_attr_state_code,
1357         &dev_attr_untuned,
1358         &dev_attr_network,
1359         &dev_attr_id,
1360         &dev_attr_port,
1361         &dev_attr_coupled,
1362         &dev_attr_local_time,
1363         &dev_attr_utc_offset,
1364         NULL
1365 };
1366 
1367 static int __init etr_register_port(struct device *dev)
1368 {
1369         struct device_attribute **attr;
1370         int rc;
1371 
1372         rc = device_register(dev);
1373         if (rc)
1374                 goto out;
1375         for (attr = etr_port_attributes; *attr; attr++) {
1376                 rc = device_create_file(dev, *attr);
1377                 if (rc)
1378                         goto out_unreg;
1379         }
1380         return 0;
1381 out_unreg:
1382         for (; attr >= etr_port_attributes; attr--)
1383                 device_remove_file(dev, *attr);
1384         device_unregister(dev);
1385 out:
1386         return rc;
1387 }
1388 
1389 static void __init etr_unregister_port(struct device *dev)
1390 {
1391         struct device_attribute **attr;
1392 
1393         for (attr = etr_port_attributes; *attr; attr++)
1394                 device_remove_file(dev, *attr);
1395         device_unregister(dev);
1396 }
1397 
1398 static int __init etr_init_sysfs(void)
1399 {
1400         int rc;
1401 
1402         rc = subsys_system_register(&etr_subsys, NULL);
1403         if (rc)
1404                 goto out;
1405         rc = device_create_file(etr_subsys.dev_root, &dev_attr_stepping_port);
1406         if (rc)
1407                 goto out_unreg_subsys;
1408         rc = device_create_file(etr_subsys.dev_root, &dev_attr_stepping_mode);
1409         if (rc)
1410                 goto out_remove_stepping_port;
1411         rc = etr_register_port(&etr_port0_dev);
1412         if (rc)
1413                 goto out_remove_stepping_mode;
1414         rc = etr_register_port(&etr_port1_dev);
1415         if (rc)
1416                 goto out_remove_port0;
1417         return 0;
1418 
1419 out_remove_port0:
1420         etr_unregister_port(&etr_port0_dev);
1421 out_remove_stepping_mode:
1422         device_remove_file(etr_subsys.dev_root, &dev_attr_stepping_mode);
1423 out_remove_stepping_port:
1424         device_remove_file(etr_subsys.dev_root, &dev_attr_stepping_port);
1425 out_unreg_subsys:
1426         bus_unregister(&etr_subsys);
1427 out:
1428         return rc;
1429 }
1430 
1431 device_initcall(etr_init_sysfs);
1432 
1433 /*
1434  * Server Time Protocol (STP) code.
1435  */
1436 static int stp_online;
1437 static struct stp_sstpi stp_info;
1438 static void *stp_page;
1439 
1440 static void stp_work_fn(struct work_struct *work);
1441 static DEFINE_MUTEX(stp_work_mutex);
1442 static DECLARE_WORK(stp_work, stp_work_fn);
1443 static struct timer_list stp_timer;
1444 
1445 static int __init early_parse_stp(char *p)
1446 {
1447         if (strncmp(p, "off", 3) == 0)
1448                 stp_online = 0;
1449         else if (strncmp(p, "on", 2) == 0)
1450                 stp_online = 1;
1451         return 0;
1452 }
1453 early_param("stp", early_parse_stp);
1454 
1455 /*
1456  * Reset STP attachment.
1457  */
1458 static void __init stp_reset(void)
1459 {
1460         int rc;
1461 
1462         stp_page = (void *) get_zeroed_page(GFP_ATOMIC);
1463         rc = chsc_sstpc(stp_page, STP_OP_CTRL, 0x0000);
1464         if (rc == 0)
1465                 set_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags);
1466         else if (stp_online) {
1467                 pr_warning("The real or virtual hardware system does "
1468                            "not provide an STP interface\n");
1469                 free_page((unsigned long) stp_page);
1470                 stp_page = NULL;
1471                 stp_online = 0;
1472         }
1473 }
1474 
1475 static void stp_timeout(unsigned long dummy)
1476 {
1477         queue_work(time_sync_wq, &stp_work);
1478 }
1479 
1480 static int __init stp_init(void)
1481 {
1482         if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
1483                 return 0;
1484         setup_timer(&stp_timer, stp_timeout, 0UL);
1485         time_init_wq();
1486         if (!stp_online)
1487                 return 0;
1488         queue_work(time_sync_wq, &stp_work);
1489         return 0;
1490 }
1491 
1492 arch_initcall(stp_init);
1493 
1494 /*
1495  * STP timing alert. There are three causes:
1496  * 1) timing status change
1497  * 2) link availability change
1498  * 3) time control parameter change
1499  * In all three cases we are only interested in the clock source state.
1500  * If a STP clock source is now available use it.
1501  */
1502 static void stp_timing_alert(struct stp_irq_parm *intparm)
1503 {
1504         if (intparm->tsc || intparm->lac || intparm->tcpc)
1505                 queue_work(time_sync_wq, &stp_work);
1506 }
1507 
1508 /*
1509  * STP sync check machine check. This is called when the timing state
1510  * changes from the synchronized state to the unsynchronized state.
1511  * After a STP sync check the clock is not in sync. The machine check
1512  * is broadcasted to all cpus at the same time.
1513  */
1514 int stp_sync_check(void)
1515 {
1516         disable_sync_clock(NULL);
1517         return 1;
1518 }
1519 
1520 /*
1521  * STP island condition machine check. This is called when an attached
1522  * server  attempts to communicate over an STP link and the servers
1523  * have matching CTN ids and have a valid stratum-1 configuration
1524  * but the configurations do not match.
1525  */
1526 int stp_island_check(void)
1527 {
1528         disable_sync_clock(NULL);
1529         return 1;
1530 }
1531 
1532 void stp_queue_work(void)
1533 {
1534         queue_work(time_sync_wq, &stp_work);
1535 }
1536 
1537 static int stp_sync_clock(void *data)
1538 {
1539         static int first;
1540         unsigned long long old_clock, delta, new_clock, clock_delta;
1541         struct clock_sync_data *stp_sync;
1542         int rc;
1543 
1544         stp_sync = data;
1545 
1546         if (xchg(&first, 1) == 1) {
1547                 /* Slave */
1548                 clock_sync_cpu(stp_sync);
1549                 return 0;
1550         }
1551 
1552         /* Wait until all other cpus entered the sync function. */
1553         while (atomic_read(&stp_sync->cpus) != 0)
1554                 cpu_relax();
1555 
1556         enable_sync_clock();
1557 
1558         rc = 0;
1559         if (stp_info.todoff[0] || stp_info.todoff[1] ||
1560             stp_info.todoff[2] || stp_info.todoff[3] ||
1561             stp_info.tmd != 2) {
1562                 old_clock = get_tod_clock();
1563                 rc = chsc_sstpc(stp_page, STP_OP_SYNC, 0);
1564                 if (rc == 0) {
1565                         new_clock = get_tod_clock();
1566                         delta = adjust_time(old_clock, new_clock, 0);
1567                         clock_delta = new_clock - old_clock;
1568                         atomic_notifier_call_chain(&s390_epoch_delta_notifier,
1569                                                    0, &clock_delta);
1570                         fixup_clock_comparator(delta);
1571                         rc = chsc_sstpi(stp_page, &stp_info,
1572                                         sizeof(struct stp_sstpi));
1573                         if (rc == 0 && stp_info.tmd != 2)
1574                                 rc = -EAGAIN;
1575                 }
1576         }
1577         if (rc) {
1578                 disable_sync_clock(NULL);
1579                 stp_sync->in_sync = -EAGAIN;
1580         } else
1581                 stp_sync->in_sync = 1;
1582         xchg(&first, 0);
1583         return 0;
1584 }
1585 
1586 /*
1587  * STP work. Check for the STP state and take over the clock
1588  * synchronization if the STP clock source is usable.
1589  */
1590 static void stp_work_fn(struct work_struct *work)
1591 {
1592         struct clock_sync_data stp_sync;
1593         int rc;
1594 
1595         /* prevent multiple execution. */
1596         mutex_lock(&stp_work_mutex);
1597 
1598         if (!stp_online) {
1599                 chsc_sstpc(stp_page, STP_OP_CTRL, 0x0000);
1600                 del_timer_sync(&stp_timer);
1601                 goto out_unlock;
1602         }
1603 
1604         rc = chsc_sstpc(stp_page, STP_OP_CTRL, 0xb0e0);
1605         if (rc)
1606                 goto out_unlock;
1607 
1608         rc = chsc_sstpi(stp_page, &stp_info, sizeof(struct stp_sstpi));
1609         if (rc || stp_info.c == 0)
1610                 goto out_unlock;
1611 
1612         /* Skip synchronization if the clock is already in sync. */
1613         if (check_sync_clock())
1614                 goto out_unlock;
1615 
1616         memset(&stp_sync, 0, sizeof(stp_sync));
1617         get_online_cpus();
1618         atomic_set(&stp_sync.cpus, num_online_cpus() - 1);
1619         stop_machine(stp_sync_clock, &stp_sync, cpu_online_mask);
1620         put_online_cpus();
1621 
1622         if (!check_sync_clock())
1623                 /*
1624                  * There is a usable clock but the synchonization failed.
1625                  * Retry after a second.
1626                  */
1627                 mod_timer(&stp_timer, jiffies + HZ);
1628 
1629 out_unlock:
1630         mutex_unlock(&stp_work_mutex);
1631 }
1632 
1633 /*
1634  * STP subsys sysfs interface functions
1635  */
1636 static struct bus_type stp_subsys = {
1637         .name           = "stp",
1638         .dev_name       = "stp",
1639 };
1640 
1641 static ssize_t stp_ctn_id_show(struct device *dev,
1642                                 struct device_attribute *attr,
1643                                 char *buf)
1644 {
1645         if (!stp_online)
1646                 return -ENODATA;
1647         return sprintf(buf, "%016llx\n",
1648                        *(unsigned long long *) stp_info.ctnid);
1649 }
1650 
1651 static DEVICE_ATTR(ctn_id, 0400, stp_ctn_id_show, NULL);
1652 
1653 static ssize_t stp_ctn_type_show(struct device *dev,
1654                                 struct device_attribute *attr,
1655                                 char *buf)
1656 {
1657         if (!stp_online)
1658                 return -ENODATA;
1659         return sprintf(buf, "%i\n", stp_info.ctn);
1660 }
1661 
1662 static DEVICE_ATTR(ctn_type, 0400, stp_ctn_type_show, NULL);
1663 
1664 static ssize_t stp_dst_offset_show(struct device *dev,
1665                                    struct device_attribute *attr,
1666                                    char *buf)
1667 {
1668         if (!stp_online || !(stp_info.vbits & 0x2000))
1669                 return -ENODATA;
1670         return sprintf(buf, "%i\n", (int)(s16) stp_info.dsto);
1671 }
1672 
1673 static DEVICE_ATTR(dst_offset, 0400, stp_dst_offset_show, NULL);
1674 
1675 static ssize_t stp_leap_seconds_show(struct device *dev,
1676                                         struct device_attribute *attr,
1677                                         char *buf)
1678 {
1679         if (!stp_online || !(stp_info.vbits & 0x8000))
1680                 return -ENODATA;
1681         return sprintf(buf, "%i\n", (int)(s16) stp_info.leaps);
1682 }
1683 
1684 static DEVICE_ATTR(leap_seconds, 0400, stp_leap_seconds_show, NULL);
1685 
1686 static ssize_t stp_stratum_show(struct device *dev,
1687                                 struct device_attribute *attr,
1688                                 char *buf)
1689 {
1690         if (!stp_online)
1691                 return -ENODATA;
1692         return sprintf(buf, "%i\n", (int)(s16) stp_info.stratum);
1693 }
1694 
1695 static DEVICE_ATTR(stratum, 0400, stp_stratum_show, NULL);
1696 
1697 static ssize_t stp_time_offset_show(struct device *dev,
1698                                 struct device_attribute *attr,
1699                                 char *buf)
1700 {
1701         if (!stp_online || !(stp_info.vbits & 0x0800))
1702                 return -ENODATA;
1703         return sprintf(buf, "%i\n", (int) stp_info.tto);
1704 }
1705 
1706 static DEVICE_ATTR(time_offset, 0400, stp_time_offset_show, NULL);
1707 
1708 static ssize_t stp_time_zone_offset_show(struct device *dev,
1709                                 struct device_attribute *attr,
1710                                 char *buf)
1711 {
1712         if (!stp_online || !(stp_info.vbits & 0x4000))
1713                 return -ENODATA;
1714         return sprintf(buf, "%i\n", (int)(s16) stp_info.tzo);
1715 }
1716 
1717 static DEVICE_ATTR(time_zone_offset, 0400,
1718                          stp_time_zone_offset_show, NULL);
1719 
1720 static ssize_t stp_timing_mode_show(struct device *dev,
1721                                 struct device_attribute *attr,
1722                                 char *buf)
1723 {
1724         if (!stp_online)
1725                 return -ENODATA;
1726         return sprintf(buf, "%i\n", stp_info.tmd);
1727 }
1728 
1729 static DEVICE_ATTR(timing_mode, 0400, stp_timing_mode_show, NULL);
1730 
1731 static ssize_t stp_timing_state_show(struct device *dev,
1732                                 struct device_attribute *attr,
1733                                 char *buf)
1734 {
1735         if (!stp_online)
1736                 return -ENODATA;
1737         return sprintf(buf, "%i\n", stp_info.tst);
1738 }
1739 
1740 static DEVICE_ATTR(timing_state, 0400, stp_timing_state_show, NULL);
1741 
1742 static ssize_t stp_online_show(struct device *dev,
1743                                 struct device_attribute *attr,
1744                                 char *buf)
1745 {
1746         return sprintf(buf, "%i\n", stp_online);
1747 }
1748 
1749 static ssize_t stp_online_store(struct device *dev,
1750                                 struct device_attribute *attr,
1751                                 const char *buf, size_t count)
1752 {
1753         unsigned int value;
1754 
1755         value = simple_strtoul(buf, NULL, 0);
1756         if (value != 0 && value != 1)
1757                 return -EINVAL;
1758         if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
1759                 return -EOPNOTSUPP;
1760         mutex_lock(&clock_sync_mutex);
1761         stp_online = value;
1762         if (stp_online)
1763                 set_bit(CLOCK_SYNC_STP, &clock_sync_flags);
1764         else
1765                 clear_bit(CLOCK_SYNC_STP, &clock_sync_flags);
1766         queue_work(time_sync_wq, &stp_work);
1767         mutex_unlock(&clock_sync_mutex);
1768         return count;
1769 }
1770 
1771 /*
1772  * Can't use DEVICE_ATTR because the attribute should be named
1773  * stp/online but dev_attr_online already exists in this file ..
1774  */
1775 static struct device_attribute dev_attr_stp_online = {
1776         .attr = { .name = "online", .mode = 0600 },
1777         .show   = stp_online_show,
1778         .store  = stp_online_store,
1779 };
1780 
1781 static struct device_attribute *stp_attributes[] = {
1782         &dev_attr_ctn_id,
1783         &dev_attr_ctn_type,
1784         &dev_attr_dst_offset,
1785         &dev_attr_leap_seconds,
1786         &dev_attr_stp_online,
1787         &dev_attr_stratum,
1788         &dev_attr_time_offset,
1789         &dev_attr_time_zone_offset,
1790         &dev_attr_timing_mode,
1791         &dev_attr_timing_state,
1792         NULL
1793 };
1794 
1795 static int __init stp_init_sysfs(void)
1796 {
1797         struct device_attribute **attr;
1798         int rc;
1799 
1800         rc = subsys_system_register(&stp_subsys, NULL);
1801         if (rc)
1802                 goto out;
1803         for (attr = stp_attributes; *attr; attr++) {
1804                 rc = device_create_file(stp_subsys.dev_root, *attr);
1805                 if (rc)
1806                         goto out_unreg;
1807         }
1808         return 0;
1809 out_unreg:
1810         for (; attr >= stp_attributes; attr--)
1811                 device_remove_file(stp_subsys.dev_root, *attr);
1812         bus_unregister(&stp_subsys);
1813 out:
1814         return rc;
1815 }
1816 
1817 device_initcall(stp_init_sysfs);
1818 

~ [ 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