RTC: Add a routine to check if the CMOS date is valid
If the CMOS is cleared or someone writes some random date/time
on purpose, the CMOS date register has a invalid date. This will
hurts some OS, like Windows 7, which hangs at MS logo forever.
When we detect that, we need to write a reasonable date in CMOS.
Alexandru Gagniuc:
Hmm, it would be interesting to use the date the coreboot image
was built and set that as the default date. At least until time
travel is invented.
Change-Id: Ic1c7a2d60e711265686441c77bdf7891a7efb42e
Signed-off-by: Zheng Bao <zheng.bao@amd.com>
Signed-off-by: zbao <fishbaozi@gmail.com>
Reviewed-on: http://review.coreboot.org/1389
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>
diff --git a/src/drivers/pc80/mc146818rtc.c b/src/drivers/pc80/mc146818rtc.c
index 99d670d..cc14a41 100644
--- a/src/drivers/pc80/mc146818rtc.c
+++ b/src/drivers/pc80/mc146818rtc.c
@@ -77,6 +77,20 @@
# define RTC_VRT 0x80 /* valid RAM and time */
/**********************************************************************/
+static void rtc_update_cmos_date(u8 has_century)
+{
+ /* Now setup a default date of Sat 1 January 2000 */
+ /* TODO: Set the time as building time? Is it reasonable? */
+ cmos_write(0, RTC_CLK_SECOND);
+ cmos_write(0, RTC_CLK_MINUTE);
+ cmos_write(1, RTC_CLK_HOUR);
+ cmos_write(7, RTC_CLK_DAYOFWEEK);
+ cmos_write(1, RTC_CLK_DAYOFMONTH);
+ cmos_write(1, RTC_CLK_MINUTE);
+ cmos_write(0, RTC_CLK_YEAR);
+ if (has_century) cmos_write(0x20, RTC_CLK_ALTCENTURY);
+}
+
#if CONFIG_USE_OPTION_TABLE
static int rtc_checksum_valid(int range_start, int range_end, int cks_loc)
{
@@ -147,14 +161,7 @@
}
if (cmos_invalid) {
- /* Now setup a default date of Sat 1 January 2000 */
- cmos_write(0, 0x00); /* seconds */
- cmos_write(0, 0x02); /* minutes */
- cmos_write(1, 0x04); /* hours */
- cmos_write(7, 0x06); /* day of week */
- cmos_write(1, 0x07); /* day of month */
- cmos_write(1, 0x08); /* month */
- cmos_write(0, 0x09); /* year */
+ rtc_update_cmos_date(RTC_HAS_NO_ALTCENTURY);
}
#endif
}
@@ -338,3 +345,23 @@
return 0;
}
#endif /* CONFIG_USE_OPTION_TABLE */
+
+/*
+ * 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.
+ */
+void rtc_check_update_cmos_date(u8 has_century)
+{
+ u8 year, century;
+
+ /* Note: We need to check if the hardware supports RTC_CLK_ALTCENTURY. */
+ century = has_century ? cmos_read(RTC_CLK_ALTCENTURY) : 0;
+ year = cmos_read(RTC_CLK_YEAR);
+
+ /* TODO: If century is 0xFF, 100% that the cmos is cleared.
+ * Other than that, so far rtc_year is the only entry to check if the date is valid. */
+ if (century > 0x99 || year > 0x99) { /* Invalid date */
+ rtc_update_cmos_date(has_century);
+ }
+}
diff --git a/src/include/pc80/mc146818rtc.h b/src/include/pc80/mc146818rtc.h
index 9f18ba4..a916761 100644
--- a/src/include/pc80/mc146818rtc.h
+++ b/src/include/pc80/mc146818rtc.h
@@ -87,6 +87,10 @@
#define RTC_CLK_DAYOFMONTH 7
#define RTC_CLK_MONTH 8
#define RTC_CLK_YEAR 9
+#define RTC_CLK_ALTCENTURY 0x32
+
+#define RTC_HAS_ALTCENTURY 1
+#define RTC_HAS_NO_ALTCENTURY 0
/* On PCs, the checksum is built only over bytes 16..45 */
#define PC_CKS_RANGE_START 16
@@ -136,6 +140,7 @@
#if !defined(__ROMCC__)
void rtc_init(int invalid);
+void rtc_check_update_cmos_date(u8 has_century);
#if CONFIG_USE_OPTION_TABLE
int set_option(const char *name, void *val);
int get_option(void *dest, const char *name);