#include <linux/acpi.h>
#endif
-unsigned int mc146818_get_time(struct rtc_time *time)
+/*
+ * Execute a function while the UIP (Update-in-progress) bit of the RTC is
+ * unset.
+ *
+ * Warning: callback may be executed more then once.
+ */
+bool mc146818_avoid_UIP(void (*callback)(unsigned char seconds, void *param),
+ void *param)
{
- unsigned char ctrl;
+ int i;
unsigned long flags;
- unsigned char century = 0;
- bool retry;
+ unsigned char seconds;
-#ifdef CONFIG_MACH_DECSTATION
- unsigned int real_year;
-#endif
+ for (i = 0; i < 10; i++) {
+ spin_lock_irqsave(&rtc_lock, flags);
-again:
- spin_lock_irqsave(&rtc_lock, flags);
- /* Ensure that the RTC is accessible. Bit 6 must be 0! */
- if (WARN_ON_ONCE((CMOS_READ(RTC_VALID) & 0x40) != 0)) {
- spin_unlock_irqrestore(&rtc_lock, flags);
- memset(time, 0xff, sizeof(*time));
- return 0;
- }
+ /*
+ * 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.
+ */
+ seconds = CMOS_READ(RTC_SECONDS);
- /*
- * 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.
- */
- time->tm_sec = CMOS_READ(RTC_SECONDS);
+ if (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP) {
+ spin_unlock_irqrestore(&rtc_lock, flags);
+ mdelay(1);
+ continue;
+ }
- if (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP) {
- spin_unlock_irqrestore(&rtc_lock, flags);
- mdelay(1);
- goto again;
- }
+ /* Revalidate the above readout */
+ if (seconds != CMOS_READ(RTC_SECONDS)) {
+ spin_unlock_irqrestore(&rtc_lock, flags);
+ continue;
+ }
- /* Revalidate the above readout */
- if (time->tm_sec != CMOS_READ(RTC_SECONDS)) {
+ if (callback)
+ callback(seconds, param);
+
+ /*
+ * Check for the UIP bit again. If it is set now then
+ * the above values may contain garbage.
+ */
+ if (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP) {
+ spin_unlock_irqrestore(&rtc_lock, flags);
+ mdelay(1);
+ continue;
+ }
+
+ /*
+ * 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...
+ */
+ if (seconds != CMOS_READ(RTC_SECONDS)) {
+ spin_unlock_irqrestore(&rtc_lock, flags);
+ continue;
+ }
spin_unlock_irqrestore(&rtc_lock, flags);
- goto again;
+
+ return true;
}
+ return false;
+}
+EXPORT_SYMBOL_GPL(mc146818_avoid_UIP);
+
+/*
+ * If the UIP (Update-in-progress) bit of the RTC is set for more then
+ * 10ms, the RTC is apparently broken or not present.
+ */
+bool mc146818_does_rtc_work(void)
+{
+ return mc146818_avoid_UIP(NULL, NULL);
+}
+EXPORT_SYMBOL_GPL(mc146818_does_rtc_work);
+
+struct mc146818_get_time_callback_param {
+ struct rtc_time *time;
+ unsigned char ctrl;
+#ifdef CONFIG_ACPI
+ unsigned char century;
+#endif
+#ifdef CONFIG_MACH_DECSTATION
+ unsigned int real_year;
+#endif
+};
+
+static void mc146818_get_time_callback(unsigned char seconds, void *param_in)
+{
+ struct mc146818_get_time_callback_param *p = param_in;
/*
* Only the values that we read from the RTC are set. We leave
* 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.
*/
- time->tm_min = CMOS_READ(RTC_MINUTES);
- time->tm_hour = CMOS_READ(RTC_HOURS);
- time->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
- time->tm_mon = CMOS_READ(RTC_MONTH);
- time->tm_year = CMOS_READ(RTC_YEAR);
+ p->time->tm_sec = seconds;
+ p->time->tm_min = CMOS_READ(RTC_MINUTES);
+ p->time->tm_hour = CMOS_READ(RTC_HOURS);
+ p->time->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
+ p->time->tm_mon = CMOS_READ(RTC_MONTH);
+ p->time->tm_year = CMOS_READ(RTC_YEAR);
#ifdef CONFIG_MACH_DECSTATION
- real_year = CMOS_READ(RTC_DEC_YEAR);
+ p->real_year = CMOS_READ(RTC_DEC_YEAR);
#endif
#ifdef CONFIG_ACPI
if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID &&
- acpi_gbl_FADT.century)
- century = CMOS_READ(acpi_gbl_FADT.century);
+ acpi_gbl_FADT.century) {
+ p->century = CMOS_READ(acpi_gbl_FADT.century);
+ } else {
+ p->century = 0;
+ }
#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);
+ p->ctrl = CMOS_READ(RTC_CONTROL);
+}
+
+int mc146818_get_time(struct rtc_time *time)
+{
+ struct mc146818_get_time_callback_param p = {
+ .time = time
+ };
- if (retry)
- goto again;
+ if (!mc146818_avoid_UIP(mc146818_get_time_callback, &p)) {
+ memset(time, 0, sizeof(*time));
+ return -EIO;
+ }
- if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
+ if (!(p.ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
{
time->tm_sec = bcd2bin(time->tm_sec);
time->tm_min = bcd2bin(time->tm_min);
time->tm_mday = bcd2bin(time->tm_mday);
time->tm_mon = bcd2bin(time->tm_mon);
time->tm_year = bcd2bin(time->tm_year);
- century = bcd2bin(century);
+#ifdef CONFIG_ACPI
+ p.century = bcd2bin(p.century);
+#endif
}
#ifdef CONFIG_MACH_DECSTATION
- time->tm_year += real_year - 72;
+ time->tm_year += p.real_year - 72;
#endif
- if (century > 20)
- time->tm_year += (century - 19) * 100;
+#ifdef CONFIG_ACPI
+ if (p.century > 19)
+ time->tm_year += (p.century - 19) * 100;
+#endif
/*
* Account for differences between how the RTC uses the values
time->tm_mon--;
- return RTC_24H;
+ return 0;
}
EXPORT_SYMBOL_GPL(mc146818_get_time);
if (yrs >= 100)
yrs -= 100;
- if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY)
- || RTC_ALWAYS_BCD) {
+ spin_lock_irqsave(&rtc_lock, flags);
+ save_control = CMOS_READ(RTC_CONTROL);
+ spin_unlock_irqrestore(&rtc_lock, flags);
+ if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
sec = bin2bcd(sec);
min = bin2bcd(min);
hrs = bin2bcd(hrs);
projects / linux-2.6-microblaze.git / blobdiff