many changes from NetBSD; better clock reading code

SCCS-vsn: sys/i386/isa/clock.c 7.4

diff --git a/usr/src/sys/i386/isa/clock.c b/usr/src/sys/i386/isa/clock.c
index 11f10ea..6bde4bc 100644 (file)
--- a/usr/src/sys/i386/isa/clock.c
+++ b/usr/src/sys/i386/isa/clock.c
@@ -7,7 +7,11 @@
  *
  * %sccs.include.redist.c%
  *
  *
  * %sccs.include.redist.c%
  *

- *     @(#)clock.c     7.3 (Berkeley) %G%
+ *     from: @(#)clock.c       7.2 (Berkeley) 5/12/91
+ *     from NetBSD: Id: clock.c,v 1.6 1993/05/22 08:01:07 cgd Exp 
+ *
+ *     @(#)clock.c     7.4 (Berkeley) %G%
+ *

  */
 
 /*
  */
 
 /*


@@ -21,16 +25,47 @@
 #include <i386/isa/isa.h>
 #include <i386/isa/rtc.h>
 
 #include <i386/isa/isa.h>
 #include <i386/isa/rtc.h>
 

+/* these should go elsewere (timerreg.h) but to avoid admin overhead... */
+/*
+ * Macros for specifying values to be written into a mode register.
+ */
+#define TIMER_CNTR0     (IO_TIMER1 + 0) /* timer 0 counter port */
+#define TIMER_CNTR1     (IO_TIMER1 + 1) /* timer 1 counter port */
+#define TIMER_CNTR2     (IO_TIMER1 + 2) /* timer 2 counter port */
+#define TIMER_MODE      (IO_TIMER1 + 3) /* timer mode port */
+#define         TIMER_SEL0      0x00    /* select counter 0 */
+#define         TIMER_SEL1      0x40    /* select counter 1 */
+#define         TIMER_SEL2      0x80    /* select counter 2 */
+#define         TIMER_INTTC     0x00    /* mode 0, intr on terminal cnt */
+#define         TIMER_ONESHOT   0x02    /* mode 1, one shot */
+#define         TIMER_RATEGEN   0x04    /* mode 2, rate generator */
+#define         TIMER_SQWAVE    0x06    /* mode 3, square wave */
+#define         TIMER_SWSTROBE  0x08    /* mode 4, s/w triggered strobe */
+#define         TIMER_HWSTROBE  0x0a    /* mode 5, h/w triggered strobe */
+#define         TIMER_LATCH     0x00    /* latch counter for reading */
+#define         TIMER_LSB       0x10    /* r/w counter LSB */
+#define         TIMER_MSB       0x20    /* r/w counter MSB */
+#define         TIMER_16BIT     0x30    /* r/w counter 16 bits, LSB first */
+#define         TIMER_BCD       0x01    /* count in BCD */
+

 #define DAYST 119
 #define DAYEN 303
 
 #define DAYST 119
 #define DAYEN 303
 

+#ifndef        XTALSPEED
+#define XTALSPEED 1193182
+#endif
+

 startrtclock() {
        int s;
 
 startrtclock() {
        int s;
 

+       findcpuspeed();         /* use the clock (while it's free)
+                                       to find the cpu speed */

        /* initialize 8253 clock */
        /* initialize 8253 clock */

-       outb (IO_TIMER1+3, 0x36);
-       outb (IO_TIMER1, 1193182/hz);
-       outb (IO_TIMER1, (1193182/hz)/256);
+       outb(TIMER_MODE, TIMER_SEL0|TIMER_RATEGEN|TIMER_16BIT);
+
+       /* Correct rounding will buy us a better precision in timekeeping */
+       outb (IO_TIMER1, (XTALSPEED+hz/2)/hz);
+       outb (IO_TIMER1, ((XTALSPEED+hz/2)/hz)/256);

 
        /* initialize brain-dead battery powered clock */
        outb (IO_RTC, RTC_STATUSA);
 
        /* initialize brain-dead battery powered clock */
        outb (IO_RTC, RTC_STATUSA);


@@ -45,6 +80,32 @@ startrtclock() {
        outb (IO_RTC+1, 0);
 }
 
        outb (IO_RTC+1, 0);
 }
 

+unsigned int delaycount;       /* calibrated loop variable (1 millisecond) */
+
+#define FIRST_GUESS    0x2000
+findcpuspeed()
+{
+       unsigned char low;
+       unsigned int remainder;
+
+       /* Put counter in count down mode */
+       outb(IO_TIMER1+3, 0x34);
+       outb(IO_TIMER1, 0xff);
+       outb(IO_TIMER1, 0xff);
+       delaycount = FIRST_GUESS;
+       spinwait(1);
+       /* Read the value left in the counter */
+       low     = inb(IO_TIMER1);       /* least siginifcant */
+       remainder = inb(IO_TIMER1);     /* most significant */
+       remainder = (remainder<<8) + low ;
+       /* Formula for delaycount is :
+        *  (loopcount * timer clock speed)/ (counter ticks * 1000)
+        */
+       delaycount = (FIRST_GUESS * (XTALSPEED/1000)) / (0xffff-remainder);
+}
+
+
+

 /* convert 2 digit BCD number */
 bcd(i)
 int i;
 /* convert 2 digit BCD number */
 bcd(i)
 int i;


@@ -60,8 +121,8 @@ int y;
        int i;
        unsigned long ret;
 
        int i;
        unsigned long ret;
 

-       ret = 0; y = y - 70;
-       for(i=0;i<y;i++) {
+       ret = 0;
+       for(i = 1970; i < y; i++) {

                if (i % 4) ret += 365*24*60*60;
                else ret += 366*24*60*60;
        }
                if (i % 4) ret += 365*24*60*60;
                else ret += 366*24*60*60;
        }


@@ -111,25 +172,24 @@ inittodr(base)
        while ((sa&RTCSA_TUP) == RTCSA_TUP)
                sa = rtcin(RTC_STATUSA);
 
        while ((sa&RTCSA_TUP) == RTCSA_TUP)
                sa = rtcin(RTC_STATUSA);
 

-       sec = bcd(rtcin(RTC_YEAR));
-       leap = !(sec % 4); sec += ytos(sec); /* year    */
+       sec = bcd(rtcin(RTC_YEAR)) + 1900;
+       if (sec < 1970)
+               sec += 100;
+       leap = !(sec % 4); sec = ytos(sec); /* year    */

        yd = mtos(bcd(rtcin(RTC_MONTH)),leap); sec += yd;       /* month   */
        t = (bcd(rtcin(RTC_DAY))-1) * 24*60*60; sec += t; yd += t; /* date    */
        day_week = rtcin(RTC_WDAY);                             /* day     */
        sec += bcd(rtcin(RTC_HRS)) * 60*60;                     /* hour    */
        sec += bcd(rtcin(RTC_MIN)) * 60;                        /* minutes */
        sec += bcd(rtcin(RTC_SEC));                             /* seconds */
        yd = mtos(bcd(rtcin(RTC_MONTH)),leap); sec += yd;       /* month   */
        t = (bcd(rtcin(RTC_DAY))-1) * 24*60*60; sec += t; yd += t; /* date    */
        day_week = rtcin(RTC_WDAY);                             /* day     */
        sec += bcd(rtcin(RTC_HRS)) * 60*60;                     /* hour    */
        sec += bcd(rtcin(RTC_MIN)) * 60;                        /* minutes */
        sec += bcd(rtcin(RTC_SEC));                             /* seconds */

-       sec -= 24*60*60; /* XXX why ??? */

 
 

-#ifdef notdef

        /* XXX off by one? Need to calculate DST on SUNDAY */
        /* Perhaps we should have the RTC hold GMT time to save */
        /* us the bother of converting. */
        /* XXX off by one? Need to calculate DST on SUNDAY */
        /* Perhaps we should have the RTC hold GMT time to save */
        /* us the bother of converting. */

-       yd = yd / 24*60*60;
+       yd = yd / (24*60*60);

        if ((yd >= DAYST) && ( yd <= DAYEN)) {
                sec -= 60*60;
        }
        if ((yd >= DAYST) && ( yd <= DAYEN)) {
                sec -= 60*60;
        }

-#endif

        sec += tz.tz_minuteswest * 60;
 
        time.tv_sec = sec;
        sec += tz.tz_minuteswest * 60;
 
        time.tv_sec = sec;


@@ -178,3 +238,17 @@ enablertclock() {
        setidt(ICU_OFFSET+0, &V(clk), SDT_SYS386IGT, SEL_KPL);
        splnone();
 }
        setidt(ICU_OFFSET+0, &V(clk), SDT_SYS386IGT, SEL_KPL);
        splnone();
 }

+
+
+
+
+spinwait(millisecs)
+int millisecs;         /* number of milliseconds to delay */
+{
+       int i, j;
+
+       for (i=0;i<millisecs;i++)
+               for (j=0;j<delaycount;j++)
+                       ;
+}
+