[Qemu-devel] [RFC v2 6/6] Add C version of rtc-test

[Anthony Liguori]

---
 Makefile   |    4 +
 rtc-test.c |  201 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 205 insertions(+), 0 deletions(-)
 create mode 100644 rtc-test.c

diff --git a/Makefile b/Makefile
index 301c75e..838cb01 100644
--- a/Makefile
+++ b/Makefile
@@ -215,6 +215,10 @@ $(qga-obj-y) qemu-ga.o: $(QGALIB_GEN) $(GENERATED_HEADERS)
 
 qemu-ga$(EXESUF): qemu-ga.o $(qga-obj-y) $(qapi-obj-y) $(tools-obj-y) 
$(qobject-obj-y) $(version-obj-y) $(QGALIB_OBJ)
 
+libqtest.o: libqtest.c
+
+rtc-test$(EXESUF): rtc-test.o libqtest.o
+
 QEMULIBS=libhw32 libhw64 libuser libdis libdis-user
 
 clean:
diff --git a/rtc-test.c b/rtc-test.c
new file mode 100644
index 0000000..01e4e49
--- /dev/null
+++ b/rtc-test.c
@@ -0,0 +1,201 @@
+#include "libqtest.h"
+
+#include <glib.h>
+#include <stdio.h>
+#include <string.h>
+
+static uint8_t base = 0x70;
+
+static int bcd2dec(int value)
+{
+    return (((value >> 4) & 0x0F) * 10) + (value & 0x0F);
+}
+
+#if 0
+static int dec2bcd(int value)
+{
+    return ((value / 10) << 4) | (value % 10);
+}
+#endif
+
+static uint8_t cmos_read(uint8_t reg)
+{
+    outb(base + 0, reg);
+    return inb(base + 1);
+}
+
+static void cmos_write(uint8_t reg, uint8_t val)
+{
+    outb(base + 0, reg);
+    outb(base + 1, val);
+}
+
+static int tm_cmp(struct tm *lhs, struct tm *rhs)
+{
+    time_t a, b;
+    struct tm d1, d2;
+
+    memcpy(&d1, lhs, sizeof(d1));
+    memcpy(&d2, rhs, sizeof(d2));
+
+    a = mktime(&d1);
+    b = mktime(&d2);
+
+    if (a < b) {
+        return -1;
+    } else if (a > b) {
+        return 1;
+    }
+
+    return 0;
+}
+
+#if 0
+static void print_tm(struct tm *tm)
+{
+    printf("%04d-%02d-%02d %02d:%02d:%02d\n",
+           tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday, 
+           tm->tm_hour, tm->tm_min, tm->tm_sec, tm->tm_gmtoff);
+}
+#endif
+
+static void cmos_get_date_time(struct tm *date)
+{
+    int base_year = 2000, hour_offset;
+    int sec, min, hour, mday, mon, year;
+    time_t ts;
+    struct tm dummy;
+
+    sec = cmos_read(0x00);
+    min = cmos_read(0x02);
+    hour = cmos_read(0x04);
+    mday = cmos_read(0x07);
+    mon = cmos_read(0x08);
+    year = cmos_read(0x09);
+
+    if ((cmos_read(0x0B) & 4) == 0) {
+        sec = bcd2dec(sec);
+        min = bcd2dec(min);
+        hour = bcd2dec(hour);
+        mday = bcd2dec(mday);
+        mon = bcd2dec(mon);
+        year = bcd2dec(year);
+        hour_offset = 80;
+    } else {
+        hour_offset = 0x80;
+    }
+
+    if ((cmos_read(0x0B) & 2) == 0) {
+        if (hour >= hour_offset) {
+            hour -= hour_offset;
+            hour += 12;
+        }
+    }
+
+    ts = time(NULL);
+    localtime_r(&ts, &dummy);
+
+    date->tm_isdst = dummy.tm_isdst;
+    date->tm_sec = sec;
+    date->tm_min = min;
+    date->tm_hour = hour;
+    date->tm_mday = mday;
+    date->tm_mon = mon - 1;
+    date->tm_year = base_year + year - 1900;
+    date->tm_gmtoff = 0;
+
+    ts = mktime(date);
+}
+
+static bool check_time(int wiggle)
+{
+    struct tm start, date[4], end;
+    struct tm *datep;
+    time_t ts;
+
+    /*
+     * This check assumes a few things.  First, we cannot guarantee that we get
+     * a consistent reading from the wall clock because we may hit an edge of
+     * the clock while reading.  To work around this, we read four clock 
readings
+     * such that at least two of them should match.  We need to assume that one
+     * reading is corrupt so we need four readings to ensure that we have at
+     * least two consecutive identical readings
+     *
+     * It's also possible that we'll cross an edge reading the host clock so
+     * simply check to make sure that the clock reading is within the period of
+     * when we expect it to be.
+     */
+
+    ts = time(NULL);
+    gmtime_r(&ts, &start);
+
+    cmos_get_date_time(&date[0]);
+    cmos_get_date_time(&date[1]);
+    cmos_get_date_time(&date[2]);
+    cmos_get_date_time(&date[3]);
+
+    ts = time(NULL);
+    gmtime_r(&ts, &end);
+
+    if (tm_cmp(&date[0], &date[1]) == 0) {
+        datep = &date[0];
+    } else if (tm_cmp(&date[1], &date[2]) == 0) {
+        datep = &date[1];
+    } else if (tm_cmp(&date[2], &date[3]) == 0) {
+        datep = &date[2];
+    } else {
+        g_assert_not_reached();
+        return false;
+    }
+
+    if (!(tm_cmp(&start, datep) <= 0 && tm_cmp(datep, &end) <= 0)) {
+        time_t t, s;
+
+        start.tm_isdst = datep->tm_isdst;
+
+        t = mktime(datep);
+        s = mktime(&start);
+        if (t < s) {
+            fprintf(stderr, "RTC is %ld second(s) behind wall-clock\n", (s - 
t));
+        } else {
+            fprintf(stderr, "RTC is %ld second(s) ahead of wall-clock\n", (t - 
s));
+        }
+
+        if (ABS(t - s) <= wiggle) {
+            return true;
+        }
+
+        return false;
+    }
+
+    return true;
+}
+
+int main(int argc, char **argv)
+{
+    // We update the RTC based on a timer that fires every second.  But there's
+    // no guarantee that we'll get the timer at any point in time so when we
+    // read the CMOS time, the timer may be pending but not yet fired.  That
+    // means we can be a few seconds behind.
+    //
+    // We really should do a gettimeofday() when CMOS time is read to get an
+    // accurate clock time but until then, give ourselves a little bit of
+    // wiggle room.
+    int wiggle = 2;
+
+    qtest_start(argv[1]);
+
+    // Set BCD mode
+    cmos_write(0x0B, cmos_read(0x0B) | 0x02);
+    if (!check_time(wiggle)) {
+        return 1;
+    }
+
+    // Set DEC mode
+    cmos_write(0x0B, cmos_read(0x0B) & ~0x02);
+    if (!check_time(wiggle)) {
+        return 1;
+    }
+
+    return 0;
+}
-- 
1.7.4.1