From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 16 Apr 2005 15:20:36 -0700 Subject: Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip! --- arch/i386/kernel/timers/timer.c | 66 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 66 insertions(+) create mode 100644 arch/i386/kernel/timers/timer.c (limited to 'arch/i386/kernel/timers/timer.c') diff --git a/arch/i386/kernel/timers/timer.c b/arch/i386/kernel/timers/timer.c new file mode 100644 index 00000000000..a3d6a288088 --- /dev/null +++ b/arch/i386/kernel/timers/timer.c @@ -0,0 +1,66 @@ +#include +#include +#include +#include + +#ifdef CONFIG_HPET_TIMER +/* + * HPET memory read is slower than tsc reads, but is more dependable as it + * always runs at constant frequency and reduces complexity due to + * cpufreq. So, we prefer HPET timer to tsc based one. Also, we cannot use + * timer_pit when HPET is active. So, we default to timer_tsc. + */ +#endif +/* list of timers, ordered by preference, NULL terminated */ +static struct init_timer_opts* __initdata timers[] = { +#ifdef CONFIG_X86_CYCLONE_TIMER + &timer_cyclone_init, +#endif +#ifdef CONFIG_HPET_TIMER + &timer_hpet_init, +#endif +#ifdef CONFIG_X86_PM_TIMER + &timer_pmtmr_init, +#endif + &timer_tsc_init, + &timer_pit_init, + NULL, +}; + +static char clock_override[10] __initdata; + +static int __init clock_setup(char* str) +{ + if (str) + strlcpy(clock_override, str, sizeof(clock_override)); + return 1; +} +__setup("clock=", clock_setup); + + +/* The chosen timesource has been found to be bad. + * Fall back to a known good timesource (the PIT) + */ +void clock_fallback(void) +{ + cur_timer = &timer_pit; +} + +/* iterates through the list of timers, returning the first + * one that initializes successfully. + */ +struct timer_opts* __init select_timer(void) +{ + int i = 0; + + /* find most preferred working timer */ + while (timers[i]) { + if (timers[i]->init) + if (timers[i]->init(clock_override) == 0) + return timers[i]->opts; + ++i; + } + + panic("select_timer: Cannot find a suitable timer\n"); + return NULL; +} -- cgit v1.2.3