Index: head/sys/kern/subr_rtc.c =================================================================== --- head/sys/kern/subr_rtc.c +++ head/sys/kern/subr_rtc.c @@ -63,8 +63,10 @@ #include #include #include -#include +#include +#include #include +#include #ifdef FFCLOCK #include #endif @@ -72,116 +74,210 @@ #include "clock_if.h" -static device_t clock_dev = NULL; -static long clock_res; -static struct timespec clock_adj; -struct mtx resettodr_lock; -MTX_SYSINIT(resettodr_init, &resettodr_lock, "tod2rl", MTX_DEF); - /* XXX: should be kern. now, it's no longer machdep. */ static int disable_rtc_set; SYSCTL_INT(_machdep, OID_AUTO, disable_rtc_set, CTLFLAG_RW, &disable_rtc_set, 0, "Disallow adjusting time-of-day clock"); +/* + * An instance of a realtime clock. A list of these tracks all the registered + * clocks in the system. + * + * The resadj member is used to apply a "resolution adjustment" equal to half + * the clock's resolution, which is useful mainly on clocks with a whole-second + * resolution. Because the clock truncates the fractional part, adding half the + * resolution performs 4/5 rounding. The same adjustment is applied to the + * times returned from clock_gettime(), because the fraction returned will + * always be zero, but on average the actual fraction at the time of the call + * should be about .5. + */ +struct rtc_instance { + device_t clockdev; + int resolution; + int flags; + struct timespec resadj; + LIST_ENTRY(rtc_instance) + rtc_entries; +}; + +/* + * Clocks are updated using a task running on taskqueue_thread. + */ +static void settime_task_func(void *arg, int pending); +static struct task settime_task = TASK_INITIALIZER(0, settime_task_func, NULL); + +/* + * Registered clocks are kept in a list which is sorted by resolution; the more + * accurate clocks get the first shot at providing the time. + */ +LIST_HEAD(rtc_listhead, rtc_instance); +static struct rtc_listhead rtc_list = LIST_HEAD_INITIALIZER(rtc_list); +static struct sx rtc_list_lock; +SX_SYSINIT(rtc_list_lock_init, &rtc_list_lock, "rtc list"); + +/* + * On the task thread, invoke the clock_settime() method of each registered + * clock. Do so holding only an sxlock, so that clock drivers are free to do + * whatever kind of locking or sleeping they need to. + */ +static void +settime_task_func(void *arg, int pending) +{ + struct timespec ts; + struct rtc_instance *rtc; + + sx_xlock(&rtc_list_lock); + LIST_FOREACH(rtc, &rtc_list, rtc_entries) { + if (!(rtc->flags & CLOCKF_SETTIME_NO_TS)) { + getnanotime(&ts); + if (!(rtc->flags & CLOCKF_SETTIME_NO_ADJ)) { + ts.tv_sec -= utc_offset(); + timespecadd(&ts, &rtc->resadj); + } + } else { + ts.tv_sec = 0; + ts.tv_nsec = 0; + } + CLOCK_SETTIME(rtc->clockdev, &ts); + } + sx_xunlock(&rtc_list_lock); +} + void -clock_register(device_t dev, long res) /* res has units of microseconds */ +clock_register_flags(device_t clockdev, long resolution, int flags) { + struct rtc_instance *rtc, *newrtc; - if (clock_dev != NULL) { - if (clock_res <= res) { - if (bootverbose) - device_printf(dev, "not installed as " - "time-of-day clock: clock %s has higher " - "resolution\n", device_get_name(clock_dev)); - return; + newrtc = malloc(sizeof(*newrtc), M_DEVBUF, M_WAITOK); + newrtc->clockdev = clockdev; + newrtc->resolution = (int)resolution; + newrtc->flags = flags; + newrtc->resadj.tv_sec = newrtc->resolution / 2 / 1000000; + newrtc->resadj.tv_nsec = newrtc->resolution / 2 % 1000000 * 1000; + + sx_xlock(&rtc_list_lock); + if (LIST_EMPTY(&rtc_list)) { + LIST_INSERT_HEAD(&rtc_list, newrtc, rtc_entries); + } else { + LIST_FOREACH(rtc, &rtc_list, rtc_entries) { + if (rtc->resolution > newrtc->resolution) { + LIST_INSERT_BEFORE(rtc, newrtc, rtc_entries); + break; + } else if (LIST_NEXT(rtc, rtc_entries) == NULL) { + LIST_INSERT_AFTER(rtc, newrtc, rtc_entries); + break; + } } - if (bootverbose) - device_printf(clock_dev, "removed as " - "time-of-day clock: clock %s has higher " - "resolution\n", device_get_name(dev)); } - clock_dev = dev; - clock_res = res; - clock_adj.tv_sec = res / 2 / 1000000; - clock_adj.tv_nsec = res / 2 % 1000000 * 1000; - if (bootverbose) - device_printf(dev, "registered as a time-of-day clock " - "(resolution %ldus, adjustment %jd.%09jds)\n", res, - (intmax_t)clock_adj.tv_sec, (intmax_t)clock_adj.tv_nsec); + sx_xunlock(&rtc_list_lock); + + device_printf(clockdev, + "registered as a time-of-day clock, resolution %d.%6.6ds\n", + newrtc->resolution / 1000000, newrtc->resolution % 1000000); } -/* - * inittodr and settodr derived from the i386 versions written - * by Christoph Robitschko , reintroduced and - * updated by Chris Stenton 8/10/94 - */ +void +clock_register(device_t dev, long res) +{ + clock_register_flags(dev, res, 0); +} + +void +clock_unregister(device_t clockdev) +{ + struct rtc_instance *rtc, *tmp; + + sx_xlock(&rtc_list_lock); + LIST_FOREACH_SAFE(rtc, &rtc_list, rtc_entries, tmp) { + if (rtc->clockdev == clockdev) { + LIST_REMOVE(rtc, rtc_entries); + free(rtc, M_DEVBUF); + } + } + sx_xunlock(&rtc_list_lock); +} + /* - * Initialize the time of day register, based on the time base which is, e.g. - * from a filesystem. + * Initialize the system time. Must be called from a context which does not + * restrict any locking or sleeping that clock drivers may need to do. + * + * First attempt to get the time from a registered realtime clock. The clocks + * are queried in order of resolution until one provides the time. If no clock + * can provide the current time, use the 'base' time provided by the caller, if + * non-zero. The 'base' time is potentially highly inaccurate, such as the last + * known good value of the system clock, or even a filesystem last-updated + * timestamp. It is used to prevent system time from appearing to move + * backwards in logs. */ void inittodr(time_t base) { struct timespec ts; + struct rtc_instance *rtc; int error; - if (clock_dev == NULL) { - printf("warning: no time-of-day clock registered, system time " - "will not be set accurately\n"); - goto wrong_time; + error = ENXIO; + sx_xlock(&rtc_list_lock); + LIST_FOREACH(rtc, &rtc_list, rtc_entries) { + if ((error = CLOCK_GETTIME(rtc->clockdev, &ts)) != 0) + continue; + if (ts.tv_sec < 0 || ts.tv_nsec < 0) { + error = EINVAL; + continue; + } + if (!(rtc->flags & CLOCKF_GETTIME_NO_ADJ)) { + timespecadd(&ts, &rtc->resadj); + ts.tv_sec += utc_offset(); + } + if (bootverbose) + device_printf(rtc->clockdev, + "providing initial system time\n"); + break; } - /* XXX: We should poll all registered RTCs in case of failure */ - mtx_lock(&resettodr_lock); - error = CLOCK_GETTIME(clock_dev, &ts); - mtx_unlock(&resettodr_lock); - if (error != 0 && error != EINVAL) { - printf("warning: clock_gettime failed (%d), the system time " - "will not be set accurately\n", error); - goto wrong_time; + sx_xunlock(&rtc_list_lock); + + /* + * Do not report errors from each clock; it is expected that some clocks + * cannot provide results in some situations. Only report problems when + * no clocks could provide the time. + */ + if (error != 0) { + switch (error) { + case ENXIO: + printf("Warning: no time-of-day clock registered, "); + break; + case EINVAL: + printf("Warning: bad time from time-of-day clock, "); + break; + default: + printf("Error reading time-of-day clock (%d), ", error); + break; + } + printf("system time will not be set accurately\n"); + ts.tv_sec = (base > 0) ? base : -1; + ts.tv_nsec = 0; } - if (error == EINVAL || ts.tv_sec < 0) { - printf("Invalid time in real time clock.\n" - "Check and reset the date immediately!\n"); - goto wrong_time; - } - ts.tv_sec += utc_offset(); - timespecadd(&ts, &clock_adj); - tc_setclock(&ts); + if (ts.tv_sec >= 0) { + tc_setclock(&ts); #ifdef FFCLOCK - ffclock_reset_clock(&ts); + ffclock_reset_clock(&ts); #endif - return; - -wrong_time: - if (base > 0) { - ts.tv_sec = base; - ts.tv_nsec = 0; - tc_setclock(&ts); } } /* - * Write system time back to RTC + * Write system time back to all registered clocks, unless disabled by admin. + * This can be called from a context that restricts locking and/or sleeping; the + * actual updating is done asynchronously on a task thread. */ void resettodr(void) { - struct timespec ts; - int error; - if (disable_rtc_set || clock_dev == NULL) + if (disable_rtc_set) return; - getnanotime(&ts); - timespecadd(&ts, &clock_adj); - ts.tv_sec -= utc_offset(); - /* XXX: We should really set all registered RTCs */ - mtx_lock(&resettodr_lock); - error = CLOCK_SETTIME(clock_dev, &ts); - mtx_unlock(&resettodr_lock); - if (error != 0) - printf("warning: clock_settime failed (%d), time-of-day clock " - "not adjusted to system time\n", error); + taskqueue_enqueue(taskqueue_thread, &settime_task); } Index: head/sys/sys/clock.h =================================================================== --- head/sys/sys/clock.h +++ head/sys/sys/clock.h @@ -54,7 +54,6 @@ */ extern int tz_minuteswest; extern int tz_dsttime; -extern struct mtx resettodr_lock; int utc_offset(void); @@ -76,7 +75,34 @@ int clock_ct_to_ts(struct clocktime *, struct timespec *); void clock_ts_to_ct(struct timespec *, struct clocktime *); -void clock_register(device_t, long); + +/* + * Time-of-day clock register/unregister functions, and associated flags. These + * functions can sleep. Upon return from unregister, the clock's methods are + * not running and will not be called again. + * + * Flags: + * + * CLOCKF_SETTIME_NO_TS + * Do not pass a timespec to clock_settime(), the driver obtains its own time + * and applies its own adjustments (this flag implies CLOCKF_SETTIME_NO_ADJ). + * + * CLOCKF_SETTIME_NO_ADJ + * Do not apply utc offset and resolution/accuracy adjustments to the value + * passed to clock_settime(), the driver applies them itself. + * + * CLOCKF_GETTIME_NO_ADJ + * Do not apply utc offset and resolution/accuracy adjustments to the value + * returned from clock_gettime(), the driver has already applied them. + */ + +#define CLOCKF_SETTIME_NO_TS 0x00000001 +#define CLOCKF_SETTIME_NO_ADJ 0x00000002 +#define CLOCKF_GETTIME_NO_ADJ 0x00000004 + +void clock_register(device_t _clockdev, long _resolution_us); +void clock_register_flags(device_t _clockdev, long _resolution_us, int _flags); +void clock_unregister(device_t _clockdev); /* * BCD to decimal and decimal to BCD.