From 64a76f667d987a559ad0726b4692c987800b22bc Mon Sep 17 00:00:00 2001 From: David Brownell Date: Tue, 29 Jul 2008 12:47:38 -0700 Subject: hpet: /dev/hpet - fixes and cleanup Minor /dev/hpet updates and bugfixes: * Remove dead code, mostly remnants of an incomplete/unusable kernel interface ... noted when addressing "sparse" warnings: + hpet_unregister() and a routine it calls + hpet_task and all references, including hpet_task_lock + hpet_data.hd_flags (and HPET_DATA_PLATFORM) * Correct and improve boot message: + displays *counter* (shared between comparators) bit width, not *timer* bit widths (which are often mixed) + relabel "timers" as "comparators"; this is less confusing, they are not independent like normal timers are (sigh) + display MHz not Hz; it's never less than 10 MHz. * Tighten and correct the userspace interface code + don't accidentally program comparators in 64-bit mode using 32-bit values ... always force comparators into 32-bit mode + provide the correct bit definition flagging comparators with periodic capability ... the ABI is unchanged * Update Documentation/hpet.txt + be more correct and current + expand description a bit + don't mention that now-gone kernel interface Plus, add a FIXME comment for something that could cause big trouble on systems with more capable HPETs than at least Intel seems to ship. It seems that few folk use this userspace interface; it's not very usable given the general lack of HPET IRQ routing. I'm told that the only real point of it any more is to mmap for fast timestamps; IMO that's handled better through the gettimeofday() vsyscall. Signed-off-by: David Brownell Acked-by: Clemens Ladisch Signed-off-by: Ingo Molnar --- arch/x86/kernel/hpet.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c index ad2b15a1334d..82d459186fd8 100644 --- a/arch/x86/kernel/hpet.c +++ b/arch/x86/kernel/hpet.c @@ -115,13 +115,17 @@ static void hpet_reserve_platform_timers(unsigned long id) hd.hd_phys_address = hpet_address; hd.hd_address = hpet; hd.hd_nirqs = nrtimers; - hd.hd_flags = HPET_DATA_PLATFORM; hpet_reserve_timer(&hd, 0); #ifdef CONFIG_HPET_EMULATE_RTC hpet_reserve_timer(&hd, 1); #endif + /* + * NOTE that hd_irq[] reflects IOAPIC input pins (LEGACY_8254 + * is wrong for i8259!) not the output IRQ. Many BIOS writers + * don't bother configuring *any* comparator interrupts. + */ hd.hd_irq[0] = HPET_LEGACY_8254; hd.hd_irq[1] = HPET_LEGACY_RTC; -- cgit v1.2.2