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path: root/src/drivers/pc80/rtc/mc146818rtc.c
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Diffstat (limited to 'src/drivers/pc80/rtc/mc146818rtc.c')
-rw-r--r--src/drivers/pc80/rtc/mc146818rtc.c23
1 files changed, 19 insertions, 4 deletions
diff --git a/src/drivers/pc80/rtc/mc146818rtc.c b/src/drivers/pc80/rtc/mc146818rtc.c
index 2029b1e51f..1d2fc97a74 100644
--- a/src/drivers/pc80/rtc/mc146818rtc.c
+++ b/src/drivers/pc80/rtc/mc146818rtc.c
@@ -81,6 +81,12 @@ static void cmos_set_checksum(int range_start, int range_end, int cks_loc)
cmos_write(((sum >> 0) & 0x0ff), cks_loc + 1);
}
+/* See if the CMOS error condition has been flagged */
+int cmos_error(void)
+{
+ return (cmos_read(RTC_VALID) & RTC_VRT) == 0;
+}
+
#define RTC_CONTROL_DEFAULT (RTC_24H)
#define RTC_FREQ_SELECT_DEFAULT (RTC_REF_CLCK_32KHZ | RTC_RATE_1024HZ)
@@ -90,7 +96,6 @@ static bool __cmos_init(bool invalid)
bool checksum_invalid = false;
bool clear_cmos;
size_t i;
- uint8_t x;
/*
* Avoid clearing pending interrupts and resetting the RTC control
@@ -104,8 +109,7 @@ static bool __cmos_init(bool invalid)
printk(BIOS_DEBUG, "RTC Init\n");
/* See if there has been a CMOS power problem. */
- x = cmos_read(RTC_VALID);
- cmos_invalid = !(x & RTC_VRT);
+ cmos_invalid = cmos_error();
if (CONFIG(USE_OPTION_TABLE)) {
/* See if there is a CMOS checksum error */
@@ -118,7 +122,7 @@ static bool __cmos_init(bool invalid)
}
if (cmos_invalid || invalid)
- cmos_write(cmos_read(RTC_CONTROL) | RTC_SET, RTC_CONTROL);
+ cmos_disable_rtc();
if (invalid || cmos_invalid || checksum_invalid) {
if (clear_cmos) {
@@ -407,6 +411,17 @@ enum cb_err set_option(const char *name, void *value)
}
/*
+ * Upon return the caller is guaranteed 244 microseconds to complete any
+ * RTC operations. wait_uip may be called a single time prior to multiple
+ * accesses, but sequences requiring more time should call wait_uip again.
+ */
+static void wait_uip(void)
+{
+ while (cmos_read(RTC_REG_A) & RTC_UIP)
+ ;
+}
+
+/*
* If the CMOS is cleared, the rtc_reg has the invalid date. That
* hurts some OSes. Even if we don't set USE_OPTION_TABLE, we need
* to make sure the date is valid.