Original version by John Hay.
Simplified timestamp code by reading the time exactly when necessary.
This may slow down the interrupt handler with extra calls to microtime(),
but only in bad configurations - the input fifo should normally be
disabled if timestamps on input are being used, since otherwise the
timestamp won't be precisely associated with any particular input event.
The interrupt handler remains slowed down by one test and branch for
each input (and now DCD change) event - avoiding this is not practical
yet.
The simplifications also fixed:
- timestamps for input sometimes being clobbered by output and modem
status interrupts.
- valid timestamps not being available unless the port is configured with
vector siointrts. siointrts no longer exists.
- compiler warnings about siointr* in some configurations.
Simplified timestamp and probe code by depending on recent changes in
microtime() and DELAY() to preserve the interrupt enable flag.
enable flag instead of enable_intr() to restore it to its usual state.
getit() is only called from DELAY() so there is no point in optimising
its speed (this wasn't so clear when it was extern), and using
enable_intr() made it inconvenient to call DELAY() from probes that need
to run with interrupts disabled.
unreasonable time. I've got a PCI mainboard that simply doesn't grok
it, so continuing with a warning (and a keyboard that's working
nevertheless :) seems to be better than spin-looping forever.
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.
regarding apm to LINT
- Disabled the statistics clock on machines which have an APM BIOS and
have the options "APM_BROKEN_STATCLOCK" enabled (which is default
in GENERIC now)
- move around some of the code in clock.c dealing with the rtc to make
it more obvios the effects of disabling the statistics clock
Reviewed by: bde
Always delay using one inb(0x84) after each i/o in rtcin() - don't
do this conditional on the bogus option DUMMY_NOPS not being defined.
If you want an optionally slightly faster rtcin() again, then inline
it and use a better named option or sysctl variable. It only needs
to be fast in rtcintr().
clock interrupts.
Keep a 1-in-16 smoothed average of the length of each tick. If the
CPU speed is correctly diagnosed, this should give experienced users
enough information to figure out a more suitable value for `tick'.
quite work yet, so the heart of it is disabled.
Added bdev and cdev args to dsopen().
drivers:
Fixed device names, links, minor numbers and modes.
wd.c:
Started actually supporting devfs.
diskslice.h:
Added devfs tokens to structs (currently 576 of them per disk! :-().
subr_diskslice.c:
Create devfs entries in dsopen() and (unsuccessfully) attempt to make
them go away at the right times. DEVFS is #undefed at the start so
that this shouldn't cause problems.
fd and wt drivers need bounce buffers, so this normally saves 32K-1K
of kernel memory.
Keep track of which DMA channels are busy. isa_dmadone() must now be
called when DMA has finished or been aborted.
Panic for unallocated and too-small (required) bounce buffers.
fd.c:
There will be new warnings about isa_dmadone() not being called after
DMA has been aborted.
sound/dmabuf.c:
isa_dmadone() needs more parameters than are available, so temporarily
use a new interface isa_dmadone_nobounce() to avoid having to worry
about panics for fake parameters. Untested.
