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-rw-r--r--drivers/rtc/rtc-cmos.c6
-rw-r--r--drivers/rtc/rtc-mc146818-lib.c37
2 files changed, 32 insertions, 11 deletions
diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c
index 2a1a83caf081..468ccd99f218 100644
--- a/drivers/rtc/rtc-cmos.c
+++ b/drivers/rtc/rtc-cmos.c
@@ -231,7 +231,7 @@ static int cmos_read_time(struct device *dev, struct rtc_time *t)
if (!pm_trace_rtc_valid())
return -EIO;
- ret = mc146818_get_time(t);
+ ret = mc146818_get_time(t, 10);
if (ret < 0) {
dev_err_ratelimited(dev, "unable to read current time\n");
return ret;
@@ -307,7 +307,7 @@ static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
*
* Use the mc146818_avoid_UIP() function to avoid this.
*/
- if (!mc146818_avoid_UIP(cmos_read_alarm_callback, &p))
+ if (!mc146818_avoid_UIP(cmos_read_alarm_callback, 10, &p))
return -EIO;
if (!(p.rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
@@ -556,7 +556,7 @@ static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
*
* Use mc146818_avoid_UIP() to avoid this.
*/
- if (!mc146818_avoid_UIP(cmos_set_alarm_callback, &p))
+ if (!mc146818_avoid_UIP(cmos_set_alarm_callback, 10, &p))
return -ETIMEDOUT;
cmos->alarm_expires = rtc_tm_to_time64(&t->time);
diff --git a/drivers/rtc/rtc-mc146818-lib.c b/drivers/rtc/rtc-mc146818-lib.c
index 43a28e82674e..4c17b3cef11e 100644
--- a/drivers/rtc/rtc-mc146818-lib.c
+++ b/drivers/rtc/rtc-mc146818-lib.c
@@ -8,26 +8,31 @@
#include <linux/acpi.h>
#endif
+#define UIP_RECHECK_DELAY 100 /* usec */
+#define UIP_RECHECK_DELAY_MS (USEC_PER_MSEC / UIP_RECHECK_DELAY)
+#define UIP_RECHECK_LOOPS_MS(x) (x / UIP_RECHECK_DELAY_MS)
+
/*
* Execute a function while the UIP (Update-in-progress) bit of the RTC is
- * unset.
+ * unset. The timeout is configurable by the caller in ms.
*
* Warning: callback may be executed more then once.
*/
bool mc146818_avoid_UIP(void (*callback)(unsigned char seconds, void *param),
+ int timeout,
void *param)
{
int i;
unsigned long flags;
unsigned char seconds;
- for (i = 0; i < 100; i++) {
+ for (i = 0; UIP_RECHECK_LOOPS_MS(i) < timeout; i++) {
spin_lock_irqsave(&rtc_lock, flags);
/*
* Check whether there is an update in progress during which the
* readout is unspecified. The maximum update time is ~2ms. Poll
- * every 100 usec for completion.
+ * for completion.
*
* Store the second value before checking UIP so a long lasting
* NMI which happens to hit after the UIP check cannot make
@@ -37,7 +42,7 @@ bool mc146818_avoid_UIP(void (*callback)(unsigned char seconds, void *param),
if (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP) {
spin_unlock_irqrestore(&rtc_lock, flags);
- udelay(100);
+ udelay(UIP_RECHECK_DELAY);
continue;
}
@@ -56,7 +61,7 @@ bool mc146818_avoid_UIP(void (*callback)(unsigned char seconds, void *param),
*/
if (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP) {
spin_unlock_irqrestore(&rtc_lock, flags);
- udelay(100);
+ udelay(UIP_RECHECK_DELAY);
continue;
}
@@ -72,6 +77,10 @@ bool mc146818_avoid_UIP(void (*callback)(unsigned char seconds, void *param),
}
spin_unlock_irqrestore(&rtc_lock, flags);
+ if (UIP_RECHECK_LOOPS_MS(i) >= 100)
+ pr_warn("Reading current time from RTC took around %li ms\n",
+ UIP_RECHECK_LOOPS_MS(i));
+
return true;
}
return false;
@@ -84,7 +93,7 @@ EXPORT_SYMBOL_GPL(mc146818_avoid_UIP);
*/
bool mc146818_does_rtc_work(void)
{
- return mc146818_avoid_UIP(NULL, NULL);
+ return mc146818_avoid_UIP(NULL, 10, NULL);
}
EXPORT_SYMBOL_GPL(mc146818_does_rtc_work);
@@ -130,13 +139,25 @@ static void mc146818_get_time_callback(unsigned char seconds, void *param_in)
p->ctrl = CMOS_READ(RTC_CONTROL);
}
-int mc146818_get_time(struct rtc_time *time)
+/**
+ * mc146818_get_time - Get the current time from the RTC
+ * @time: pointer to struct rtc_time to store the current time
+ * @timeout: timeout value in ms
+ *
+ * This function reads the current time from the RTC and stores it in the
+ * provided struct rtc_time. The timeout parameter specifies the maximum
+ * time to wait for the RTC to become ready.
+ *
+ * Return: 0 on success, -ETIMEDOUT if the RTC did not become ready within
+ * the specified timeout, or another error code if an error occurred.
+ */
+int mc146818_get_time(struct rtc_time *time, int timeout)
{
struct mc146818_get_time_callback_param p = {
.time = time
};
- if (!mc146818_avoid_UIP(mc146818_get_time_callback, &p)) {
+ if (!mc146818_avoid_UIP(mc146818_get_time_callback, timeout, &p)) {
memset(time, 0, sizeof(*time));
return -ETIMEDOUT;
}