diff options
Diffstat (limited to 'sys/amd64/isa')
| -rw-r--r-- | sys/amd64/isa/clock.c | 25 |
1 files changed, 16 insertions, 9 deletions
diff --git a/sys/amd64/isa/clock.c b/sys/amd64/isa/clock.c index 49b7bbf..0b1fc4d 100644 --- a/sys/amd64/isa/clock.c +++ b/sys/amd64/isa/clock.c @@ -115,6 +115,7 @@ static u_int32_t i8254_offset; static int (*i8254_pending)(struct intsrc *); static int i8254_ticked; static int using_lapic_timer; +static int rtc_reg = -1; static u_char rtc_statusa = RTCSA_DIVIDER | RTCSA_NOPROF; static u_char rtc_statusb = RTCSB_24HR; @@ -421,24 +422,30 @@ rtcin(reg) u_char val; RTC_LOCK; - outb(IO_RTC, reg); - inb(0x84); + if (rtc_reg != reg) { + inb(0x84); + outb(IO_RTC, reg); + rtc_reg = reg; + inb(0x84); + } val = inb(IO_RTC + 1); - inb(0x84); RTC_UNLOCK; return (val); } -static __inline void -writertc(u_char reg, u_char val) +static void +writertc(int reg, u_char val) { RTC_LOCK; - inb(0x84); - outb(IO_RTC, reg); - inb(0x84); + if (rtc_reg != reg) { + inb(0x84); + outb(IO_RTC, reg); + rtc_reg = reg; + inb(0x84); + } outb(IO_RTC + 1, val); - inb(0x84); /* XXX work around wrong order in rtcin() */ + inb(0x84); RTC_UNLOCK; } |
