diff options
| -rw-r--r-- | sys/dev/efidev/efirtc.c | 78 |
1 files changed, 65 insertions, 13 deletions
diff --git a/sys/dev/efidev/efirtc.c b/sys/dev/efidev/efirtc.c index 1444c352d79e..152a4912dbce 100644 --- a/sys/dev/efidev/efirtc.c +++ b/sys/dev/efidev/efirtc.c @@ -41,21 +41,20 @@ __FBSDID("$FreeBSD$"); #include "clock_if.h" +static bool efirtc_zeroes_subseconds; +static struct timespec efirtc_resadj; + +static const u_int us_per_s = 1000000; +static const u_int ns_per_s = 1000000000; +static const u_int ns_per_us = 1000; + static void efirtc_identify(driver_t *driver, device_t parent) { - struct efi_tm tm; - int error; - /* - * Check if we can read the time. This will stop us attaching when - * there is no EFI Runtime support, or the gettime function is - * unimplemented, e.g. on some builds of U-Boot. - */ - error = efi_get_time(&tm); - if (error != 0) + /* Don't add the driver unless we have working runtime services. */ + if (efi_rt_ok() != 0) return; - if (device_find_child(parent, "efirtc", -1) != NULL) return; if (BUS_ADD_CHILD(parent, 0, "efirtc", -1) == NULL) @@ -65,16 +64,58 @@ efirtc_identify(driver_t *driver, device_t parent) static int efirtc_probe(device_t dev) { + struct efi_tm tm; + int error; - device_quiet(dev); - return (0); + /* + * Check whether we can read the time. This will stop us from attaching + * when there is EFI Runtime support but the gettime function is + * unimplemented, e.g. on some builds of U-Boot. + */ + if ((error = efi_get_time(&tm)) != 0) { + if (bootverbose) + device_printf(dev, "cannot read EFI realtime clock\n"); + return (error); + } + device_set_desc(dev, "EFI Realtime Clock"); + return (BUS_PROBE_DEFAULT); } static int efirtc_attach(device_t dev) { + struct efi_tmcap tmcap; + long res; + int error; + + bzero(&tmcap, sizeof(tmcap)); + if ((error = efi_get_time_capabilities(&tmcap)) != 0) { + device_printf(dev, "cannot get EFI time capabilities"); + return (error); + } + + /* Translate resolution in Hz to tick length in usec. */ + if (tmcap.tc_res == 0) + res = us_per_s; /* 0 is insane, assume 1 Hz. */ + else if (tmcap.tc_res > us_per_s) + res = 1; /* 1us is the best we can represent */ + else + res = us_per_s / tmcap.tc_res; + + /* Clock rounding adjustment is 1/2 of resolution, in nsec. */ + efirtc_resadj.tv_nsec = (res * ns_per_us) / 2; + + /* Does the clock zero the subseconds when time is set? */ + efirtc_zeroes_subseconds = tmcap.tc_stz; + + /* + * Register. If the clock zeroes out the subseconds when it's set, + * schedule the SetTime calls to happen just before top-of-second. + */ + clock_register_flags(dev, res, CLOCKF_SETTIME_NO_ADJ); + if (efirtc_zeroes_subseconds) + clock_schedule(dev, ns_per_s - ns_per_us); - clock_register(dev, 1000000); return (0); } @@ -105,6 +146,7 @@ efirtc_gettime(device_t dev, struct timespec *ts) ct.year = tm.tm_year; ct.nsec = tm.tm_nsec; + clock_dbgprint_ct(dev, CLOCK_DBG_READ, &ct); return (clock_ct_to_ts(&ct, ts)); } @@ -114,7 +156,17 @@ efirtc_settime(device_t dev, struct timespec *ts) struct clocktime ct; struct efi_tm tm; + /* + * We request a timespec with no resolution-adjustment so that we can + * apply it ourselves based on whether or not the clock zeroes the + * sub-second part of the time when setting the time. + */ + ts->tv_sec -= utc_offset(); + if (!efirtc_zeroes_subseconds) + timespecadd(ts, &efirtc_resadj); + clock_ts_to_ct(ts, &ct); + clock_dbgprint_ct(dev, CLOCK_DBG_WRITE, &ct); bzero(&tm, sizeof(tm)); tm.tm_sec = ct.sec; |