diff options
| author | Paolo Bonzini <pbonzini@redhat.com> | 2012-10-01 14:22:07 +0200 |
|---|---|---|
| committer | Anthony Liguori <aliguori@us.ibm.com> | 2012-10-05 08:02:30 -0500 |
| commit | e67edb943f0c812530aaae2491da56f9542f928b (patch) | |
| tree | 882a919b6e3490b4050d6c914d2a4c22bf0ea1e8 /hw/mc146818rtc.c | |
| parent | b6db4aca20e9af4f62c9c9e08b9b9672a6ed3390 (diff) | |
rtc: map CMOS index 0x37 to 0x32 on read and writes
QEMU's attempt to implement the century byte cover two possible places
for the byte. A common one on modern chipsets is 0x32, but QEMU also
stores the value in 0x37 (apparently for IBM PS/2 compatibility---it's
only been 25 years). To simplify the implementation of the century
byte, store it only at 0x32 but remap transparently 0x37 to 0x32 when
reading and writing from CMOS.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Diffstat (limited to 'hw/mc146818rtc.c')
| -rw-r--r-- | hw/mc146818rtc.c | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/hw/mc146818rtc.c b/hw/mc146818rtc.c index d63554f89..a7d20d5c2 100644 --- a/hw/mc146818rtc.c +++ b/hw/mc146818rtc.c @@ -399,6 +399,10 @@ static void cmos_ioport_write(void *opaque, uint32_t addr, uint32_t data) s->cmos_data[s->cmos_index] = data; check_update_timer(s); break; + case RTC_IBM_PS2_CENTURY_BYTE: + s->cmos_index = RTC_CENTURY; + /* fall through */ + case RTC_CENTURY: case RTC_SECONDS: case RTC_MINUTES: case RTC_HOURS: @@ -598,6 +602,10 @@ static uint32_t cmos_ioport_read(void *opaque, uint32_t addr) return 0xff; } else { switch(s->cmos_index) { + case RTC_IBM_PS2_CENTURY_BYTE: + s->cmos_index = RTC_CENTURY; + /* fall through */ + case RTC_CENTURY: case RTC_SECONDS: case RTC_MINUTES: case RTC_HOURS: @@ -661,10 +669,6 @@ void rtc_set_memory(ISADevice *dev, int addr, int val) s->cmos_data[addr] = val; } -/* PC cmos mappings */ -#define REG_IBM_CENTURY_BYTE 0x32 -#define REG_IBM_PS2_CENTURY_BYTE 0x37 - static void rtc_set_date_from_host(ISADevice *dev) { RTCState *s = DO_UPCAST(RTCState, dev, dev); @@ -681,8 +685,7 @@ static void rtc_set_date_from_host(ISADevice *dev) rtc_set_cmos(s, &tm); val = rtc_to_bcd(s, (tm.tm_year / 100) + 19); - rtc_set_memory(dev, REG_IBM_CENTURY_BYTE, val); - rtc_set_memory(dev, REG_IBM_PS2_CENTURY_BYTE, val); + rtc_set_memory(dev, RTC_CENTURY, val); } static int rtc_post_load(void *opaque, int version_id) |