vbatts/grub
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2008-08-05 Robert Millan <rmh@aybabtu.com>

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* conf/i386-pc.rmk (kernel_img_SOURCES): Add `kern/i386/pit.c'.
        * conf/i386-efi.rmk (kernel_mod_SOURCES): Likewise.
        * conf/i386-coreboot.rmk (kernel_elf_SOURCES): Likewise. Also add
        `kern/i386/tsc.c', `kern/generic/rtc_get_time_ms.c' and
        `kern/generic/millisleep.c'.

        * kern/i386/tsc.c (calibrate_tsc): Rewrite using grub_pit_wait()
        instead of grub_get_rtc().
        (grub_tsc_init): Initialize `tsc_boot_time'.

        * kern/i386/linuxbios/init.c (grub_millisleep): Remove stub.
        (grub_machine_init): Use grub_tsc_init() rather than
        installing an RTC-based handler via grub_install_get_time_ms().

        * kern/i386/pit.c: New file.
        * include/grub/i386/pit.h: Likewise.
This commit is contained in:
robertmh 2008-08-05 20:24:00 +00:00
parent 9e7007b310
commit 24371d2620
9 changed files with 90 additions and 42 deletions
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39
kern/i386/tsc.c
View file

@ -25,8 +25,7 @@
#include <grub/misc.h>
#include <grub/i386/tsc.h>
/* Calibrated reference for TSC=0. This defines the time since the epoch in
milliseconds that TSC=0 refers to. */
/* This defines the value TSC had at the epoch (that is, when we calibrated it). */
static grub_uint64_t tsc_boot_time;
/* Calibrated TSC rate. (In TSC ticks per millisecond.) */
@ -47,44 +46,15 @@ grub_tsc_get_time_ms (void)
static void
calibrate_tsc (void)
{
/* First calbrate the TSC rate (relative, not absolute time). */
/* First calibrate the TSC rate (relative, not absolute time). */
grub_uint64_t start_tsc;
grub_uint64_t end_tsc;
grub_uint32_t initial_tick;
grub_uint32_t start_tick;
grub_uint32_t end_tick;
/* Wait for the start of the next tick;
we'll base out timing off this edge. */
initial_tick = grub_get_rtc ();
do
{
start_tick = grub_get_rtc ();
}
while (start_tick == initial_tick);
start_tsc = grub_get_tsc ();
/* Wait for the start of the next tick. This will
be the end of the 1-tick period. */
do
{
end_tick = grub_get_rtc ();
}
while (end_tick - start_tick < CALIBRATION_TICKS);
grub_pit_wait (0xffff);
end_tsc = grub_get_tsc ();
tsc_ticks_per_ms =
grub_divmod64 (grub_divmod64
(end_tsc - start_tsc, end_tick - start_tick, 0)
* GRUB_TICKS_PER_SECOND, 1000, 0);
/* Reference the TSC zero (boot time) to the epoch to
get an absolute real time reference. */
grub_uint64_t ms_since_boot = grub_divmod64 (end_tsc, tsc_ticks_per_ms, 0);
grub_uint64_t mstime_now = grub_divmod64 ((grub_uint64_t) 1000 * end_tick,
GRUB_TICKS_PER_SECOND,
0);
tsc_boot_time = mstime_now - ms_since_boot;
tsc_ticks_per_ms = grub_divmod64 (end_tsc - start_tsc, 55, 0);
}
void
@ -92,6 +62,7 @@ grub_tsc_init (void)
{
if (grub_cpu_is_tsc_supported ())
{
tsc_boot_time = grub_get_tsc ();
calibrate_tsc ();
grub_install_get_time_ms (grub_tsc_get_time_ms);
}