freebsd-nq/sys/isa
Bruce Evans 2dafbfcbab Added calibration the i8254 and the i586 clocks agains the RTC at boot
time.  The results are currently ignored unless certain temporary options
are used.

Added sysctls to support reading and writing the clock frequency variables
(not the frequencies themselves).  Writing is supposed to atomically
adjust all related variables.

machdep.c:
Fixed spelling of a function name in a comment so that I can log this
message which should have been with the previous commit.

Initialize `cpu_class' earlier so that it can be used in startrtclock()
instead of in calibrate_cyclecounter() (which no longer exists).

Removed range checking of `cpu'.  It is always initialized to CPU_XXX
so it is less likely to be out of bounds than most variables.

clock.h:
Removed I586_CYCLECTR().  Use rdtsc() instead.

clock.c:
TIMER_FREQ is now a variable timer_freq that defaults to the old value of
TIMER_FREQ.  #define'ing TIMER_FREQ should still work and may be the best
way of setting the frequency.

Calibration involves counting cycles while watching the RTC for one second.
This gives values correct to within (a few ppm) + (the innaccuracy of the
RTC) on my systems.
1996-05-01 08:39:02 +00:00
..
ic Oops, this should have been committed with the other Hayes ESP changes. 1995-12-29 13:18:58 +00:00
atrtc.c Added calibration the i8254 and the i586 clocks agains the RTC at boot 1996-05-01 08:39:02 +00:00
fd.c Update drivers to use isa_dma_acquire() and isa_dma_release() 1996-04-08 19:40:57 +00:00
fdc.h Peter's work to work around one of the most annoying bugs in the 1995-01-06 15:20:00 +00:00
fdreg.h An ifdef almost hit where it was supposed to go. Joerg owes me a good 1994-09-25 23:37:38 +00:00
joy.c Switched from using devfs_add_sw() to using devfs_add_swf() 1996-03-28 14:29:52 +00:00
kbdtables.h Change RUKEYMAP sligtly 1996-01-25 16:37:20 +00:00
rtc.h BIOS manufacturers don't seem to have a unique idea about 2.88 MB 1995-10-09 15:00:39 +00:00
sio.c Format the already applied PCCARD additions to use KNF form. No 1996-04-23 18:36:56 +00:00
sioreg.h Staticize and cleanup. 1995-12-10 13:40:44 +00:00
syscons.c Fixed a race that caused panics in kernel printfs when the screen timeout 1996-05-01 03:58:21 +00:00
syscons.h Fix a bunch of spelling errors in the comment fields of 1996-01-30 23:02:38 +00:00
timerreg.h Removed all patch kit headers, sccsid and rcsid strings, put $Id$ in, some 1993-10-16 13:48:52 +00:00