diff options
Diffstat (limited to 'drivers/rtc')
| -rw-r--r-- | drivers/rtc/Makefile | 1 | ||||
| -rw-r--r-- | drivers/rtc/class.c | 9 | ||||
| -rw-r--r-- | drivers/rtc/rtc-cmos.c | 3 | ||||
| -rw-r--r-- | drivers/rtc/rtc-mc146818-lib.c | 70 | ||||
| -rw-r--r-- | drivers/rtc/systohc.c | 61 |
5 files changed, 51 insertions, 93 deletions
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile index bfb57464118d..bb8f319b09fb 100644 --- a/drivers/rtc/Makefile +++ b/drivers/rtc/Makefile @@ -6,7 +6,6 @@ ccflags-$(CONFIG_RTC_DEBUG) := -DDEBUG obj-$(CONFIG_RTC_LIB) += lib.o -obj-$(CONFIG_RTC_SYSTOHC) += systohc.o obj-$(CONFIG_RTC_CLASS) += rtc-core.o obj-$(CONFIG_RTC_MC146818_LIB) += rtc-mc146818-lib.o rtc-core-y := class.o interface.o diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c index 5c6748dfa55d..7e470fbd5e4d 100644 --- a/drivers/rtc/class.c +++ b/drivers/rtc/class.c @@ -201,8 +201,13 @@ static struct rtc_device *rtc_allocate_device(void) device_initialize(&rtc->dev); - /* Drivers can revise this default after allocating the device. */ - rtc->set_offset_nsec = NSEC_PER_SEC / 2; + /* + * Drivers can revise this default after allocating the device. + * The default is what most RTCs do: Increment seconds exactly one + * second after the write happened. This adds a default transport + * time of 5ms which is at least halfways close to reality. + */ + rtc->set_offset_nsec = NSEC_PER_SEC + 5 * NSEC_PER_MSEC; rtc->irq_freq = 1; rtc->max_user_freq = 64; diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c index 83415600185c..51e80bc70d42 100644 --- a/drivers/rtc/rtc-cmos.c +++ b/drivers/rtc/rtc-cmos.c @@ -867,6 +867,9 @@ cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq) if (retval) goto cleanup2; + /* Set the sync offset for the periodic 11min update correct */ + cmos_rtc.rtc->set_offset_nsec = NSEC_PER_SEC / 2; + /* export at least the first block of NVRAM */ nvmem_cfg.size = address_space - NVRAM_OFFSET; devm_rtc_nvmem_register(cmos_rtc.rtc, &nvmem_cfg); diff --git a/drivers/rtc/rtc-mc146818-lib.c b/drivers/rtc/rtc-mc146818-lib.c index 2ecd8752b088..972a5b9a629d 100644 --- a/drivers/rtc/rtc-mc146818-lib.c +++ b/drivers/rtc/rtc-mc146818-lib.c @@ -8,41 +8,41 @@ #include <linux/acpi.h> #endif -/* - * Returns true if a clock update is in progress - */ -static inline unsigned char mc146818_is_updating(void) -{ - unsigned char uip; - unsigned long flags; - - spin_lock_irqsave(&rtc_lock, flags); - uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP); - spin_unlock_irqrestore(&rtc_lock, flags); - return uip; -} - unsigned int mc146818_get_time(struct rtc_time *time) { unsigned char ctrl; unsigned long flags; unsigned char century = 0; + bool retry; #ifdef CONFIG_MACH_DECSTATION unsigned int real_year; #endif +again: + spin_lock_irqsave(&rtc_lock, flags); /* - * read RTC once any update in progress is done. The update - * can take just over 2ms. We wait 20ms. There is no need to - * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP. - * If you need to know *exactly* when a second has started, enable - * periodic update complete interrupts, (via ioctl) and then - * immediately read /dev/rtc which will block until you get the IRQ. - * Once the read clears, read the RTC time (again via ioctl). Easy. + * Check whether there is an update in progress during which the + * readout is unspecified. The maximum update time is ~2ms. Poll + * every msec for completion. + * + * Store the second value before checking UIP so a long lasting NMI + * which happens to hit after the UIP check cannot make an update + * cycle invisible. */ - if (mc146818_is_updating()) - mdelay(20); + time->tm_sec = CMOS_READ(RTC_SECONDS); + + if (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP) { + spin_unlock_irqrestore(&rtc_lock, flags); + mdelay(1); + goto again; + } + + /* Revalidate the above readout */ + if (time->tm_sec != CMOS_READ(RTC_SECONDS)) { + spin_unlock_irqrestore(&rtc_lock, flags); + goto again; + } /* * Only the values that we read from the RTC are set. We leave @@ -50,8 +50,6 @@ unsigned int mc146818_get_time(struct rtc_time *time) * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated * by the RTC when initially set to a non-zero value. */ - spin_lock_irqsave(&rtc_lock, flags); - time->tm_sec = CMOS_READ(RTC_SECONDS); time->tm_min = CMOS_READ(RTC_MINUTES); time->tm_hour = CMOS_READ(RTC_HOURS); time->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH); @@ -66,8 +64,24 @@ unsigned int mc146818_get_time(struct rtc_time *time) century = CMOS_READ(acpi_gbl_FADT.century); #endif ctrl = CMOS_READ(RTC_CONTROL); + /* + * Check for the UIP bit again. If it is set now then + * the above values may contain garbage. + */ + retry = CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP; + /* + * A NMI might have interrupted the above sequence so check whether + * the seconds value has changed which indicates that the NMI took + * longer than the UIP bit was set. Unlikely, but possible and + * there is also virt... + */ + retry |= time->tm_sec != CMOS_READ(RTC_SECONDS); + spin_unlock_irqrestore(&rtc_lock, flags); + if (retry) + goto again; + if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { time->tm_sec = bcd2bin(time->tm_sec); @@ -121,7 +135,6 @@ int mc146818_set_time(struct rtc_time *time) if (yrs > 255) /* They are unsigned */ return -EINVAL; - spin_lock_irqsave(&rtc_lock, flags); #ifdef CONFIG_MACH_DECSTATION real_yrs = yrs; leap_yr = ((!((yrs + 1900) % 4) && ((yrs + 1900) % 100)) || @@ -150,10 +163,8 @@ int mc146818_set_time(struct rtc_time *time) /* These limits and adjustments are independent of * whether the chip is in binary mode or not. */ - if (yrs > 169) { - spin_unlock_irqrestore(&rtc_lock, flags); + if (yrs > 169) return -EINVAL; - } if (yrs >= 100) yrs -= 100; @@ -169,6 +180,7 @@ int mc146818_set_time(struct rtc_time *time) century = bin2bcd(century); } + spin_lock_irqsave(&rtc_lock, flags); save_control = CMOS_READ(RTC_CONTROL); CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL); save_freq_select = CMOS_READ(RTC_FREQ_SELECT); diff --git a/drivers/rtc/systohc.c b/drivers/rtc/systohc.c deleted file mode 100644 index 8b70f0520e13..000000000000 --- a/drivers/rtc/systohc.c +++ /dev/null @@ -1,61 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -#include <linux/rtc.h> -#include <linux/time.h> - -/** - * rtc_set_ntp_time - Save NTP synchronized time to the RTC - * @now: Current time of day - * @target_nsec: pointer for desired now->tv_nsec value - * - * Replacement for the NTP platform function update_persistent_clock64 - * that stores time for later retrieval by rtc_hctosys. - * - * Returns 0 on successful RTC update, -ENODEV if a RTC update is not - * possible at all, and various other -errno for specific temporary failure - * cases. - * - * -EPROTO is returned if now.tv_nsec is not close enough to *target_nsec. - * - * If temporary failure is indicated the caller should try again 'soon' - */ -int rtc_set_ntp_time(struct timespec64 now, unsigned long *target_nsec) -{ - struct rtc_device *rtc; - struct rtc_time tm; - struct timespec64 to_set; - int err = -ENODEV; - bool ok; - - rtc = rtc_class_open(CONFIG_RTC_SYSTOHC_DEVICE); - if (!rtc) - goto out_err; - - if (!rtc->ops || !rtc->ops->set_time) - goto out_close; - - /* Compute the value of tv_nsec we require the caller to supply in - * now.tv_nsec. This is the value such that (now + - * set_offset_nsec).tv_nsec == 0. - */ - set_normalized_timespec64(&to_set, 0, -rtc->set_offset_nsec); - *target_nsec = to_set.tv_nsec; - - /* The ntp code must call this with the correct value in tv_nsec, if - * it does not we update target_nsec and return EPROTO to make the ntp - * code try again later. - */ - ok = rtc_tv_nsec_ok(rtc->set_offset_nsec, &to_set, &now); - if (!ok) { - err = -EPROTO; - goto out_close; - } - - rtc_time64_to_tm(to_set.tv_sec, &tm); - - err = rtc_set_time(rtc, &tm); - -out_close: - rtc_class_close(rtc); -out_err: - return err; -} |