Support CMOS RTC based on MC148618A RTC by overriding get_unix_time()
function. This is needed for the timeout API previously added.
Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez at hitachi.com>
---
purgatory/arch/i386/Makefile | 1
purgatory/arch/i386/rtc_cmos.c | 104 ++++++++++++++++++++++++++++++++++++++++
purgatory/arch/x86_64/Makefile | 1
3 files changed, 106 insertions(+)
create mode 100644 purgatory/arch/i386/rtc_cmos.c
diff --git a/purgatory/arch/i386/Makefile b/purgatory/arch/i386/Makefile
index 1532219..cb77328 100644
--- a/purgatory/arch/i386/Makefile
+++ b/purgatory/arch/i386/Makefile
@@ -13,6 +13,7 @@ i386_PURGATORY_SRCS += purgatory/arch/i386/console-x86.c
i386_PURGATORY_SRCS += purgatory/arch/i386/vga.c
i386_PURGATORY_SRCS += purgatory/arch/i386/pic.c
i386_PURGATORY_SRCS += purgatory/arch/i386/crashdump_backup.c
+i386_PURGATORY_SRCS += purgatory/arch/i386/rtc_cmos.c
dist += purgatory/arch/i386/Makefile $(i386_PURGATORY_SRCS) \
purgatory/arch/i386/purgatory-x86.h \
diff --git a/purgatory/arch/i386/rtc_cmos.c b/purgatory/arch/i386/rtc_cmos.c
new file mode 100644
index 0000000..3dbbd01
--- /dev/null
+++ b/purgatory/arch/i386/rtc_cmos.c
@@ -0,0 +1,104 @@
+#include <sys/io.h>
+#include "time.h"
+
+#define CMOS_PORT0 0x70
+#define CMOS_NMI_DISABLE 0x80
+#define CMOS_PORT1 0x71
+
+#define RTC_SECONDS 0x00
+#define RTC_MINUTES 0x02
+#define RTC_HOURS 0x04
+#define RTC_DAY 0x07
+#define RTC_MONTH 0x08
+#define RTC_YEAR 0x09
+
+#define RTC_REGA 0x0a
+#define RTC_UIP 0x80
+#define RTC_REGB 0x0b
+#define RTC_HOURFORM 0x02
+#define RTC_DM 0x04
+
+static int is_bcd; /* 1 if the Data Mode is BCD */
+static int is_12hr; /* 1 if the Hour Format is 12-hr mode */
+
+unsigned char read_cmos(int idx)
+{
+ static unsigned char nmi_disable_bit = 0xff;
+
+ /* Preserve NMI Disable bit at the first time */
+ if (nmi_disable_bit == 0xff)
+ nmi_disable_bit = inb(CMOS_PORT0) & CMOS_NMI_DISABLE;
+
+ outb(nmi_disable_bit | (idx & 0x7f), CMOS_PORT0);
+
+ return inb(CMOS_PORT1);
+}
+
+/**
+ * Return UNIX-epoch time.
+ *
+ * If the RTC is about to be updated (UIP bit is set), this function wait
+ * for that. It takes at most 2228us with MC146818A RTC according to
+ * the specification. Modern MC146818A-compatible RTCs in chipset will work
+ * faster, but not so much. So you shouldn't call this function too often.
+ */
+time64_t get_unix_time(void)
+{
+ static int is_first_time = 1;
+ unsigned char byte;
+ int ss, mm, hh;
+ int day, mon, year;
+ int is_pm;
+
+ /* Check the modes at the first time. */
+ if (is_first_time) {
+ byte = read_cmos(RTC_REGB);
+ if (!(byte & RTC_DM))
+ is_bcd = 1;
+
+ if (!(byte & RTC_HOURFORM))
+ is_12hr = 1;
+
+ is_first_time = 0;
+ }
+
+ /* Wait for the clock update to be done if it is in progress */
+ do {
+ byte = read_cmos(RTC_REGA);
+ } while (byte & RTC_UIP);
+
+
+ /*
+ * Now, we have 244us at least until the clock update will start.
+ */
+ ss = read_cmos(RTC_SECONDS);
+ mm = read_cmos(RTC_MINUTES);
+ hh = read_cmos(RTC_HOURS);
+ day = read_cmos(RTC_DAY);
+ mon = read_cmos(RTC_MONTH);
+ year = read_cmos(RTC_YEAR);
+
+ /* If the RTC is in 12-hr mode, bit-7 of HOUR byte indicates PM. */
+ is_pm = (hh & 0x80);
+ hh &= 0x7f; /* drop AM/PM bit */
+
+ if (is_bcd) {
+ ss = (ss >> 4) * 10 + (ss & 0xf);
+ mm = (mm >> 4) * 10 + (mm & 0xf);
+ hh = (hh >> 4) * 10 + (hh & 0xf);
+ day = (day >> 4) * 10 + (day & 0xf);
+ mon = (mon >> 4) * 10 + (mon & 0xf);
+ year = (year >> 4) * 10 + (year & 0xf) +
+ 2000; /* FIXME? */
+ }
+
+ if (is_12hr) {
+ if (is_pm && hh != 12)
+ hh += 12;
+
+ if (!is_pm && hh == 12)
+ hh = 0;
+ }
+
+ return date2unix(year, mon, day, hh, mm, ss);
+}
diff --git a/purgatory/arch/x86_64/Makefile b/purgatory/arch/x86_64/Makefile
index 7300937..bca1f71 100644
--- a/purgatory/arch/x86_64/Makefile
+++ b/purgatory/arch/x86_64/Makefile
@@ -22,5 +22,6 @@ x86_64_PURGATORY_SRCS += purgatory/arch/i386/crashdump_backup.c
x86_64_PURGATORY_SRCS += purgatory/arch/i386/console-x86.c
x86_64_PURGATORY_SRCS += purgatory/arch/i386/vga.c
x86_64_PURGATORY_SRCS += purgatory/arch/i386/pic.c
+x86_64_PURGATORY_SRCS += purgatory/arch/i386/rtc_cmos.c
x86_64_PURGATORY_EXTRA_CFLAGS = -mcmodel=large
