mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-11-24 23:20:50 +07:00
458f69ef36
The conversion here is really trivial: just a bunch of title markups and very few puntual changes is enough to make it to be parsed by Sphinx and generate a nice html. The conversion is actually: - add blank lines and identation in order to identify paragraphs; - fix tables markups; - add some lists markups; - mark literal blocks; - adjust title markups. At its new index.rst, let's add a :orphan: while this is not linked to the main index.rst file, in order to avoid build warnings. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Acked-by: Mark Brown <broonie@kernel.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
31 lines
1.5 KiB
ReStructuredText
31 lines
1.5 KiB
ReStructuredText
===========================================
|
|
High Precision Event Timer Driver for Linux
|
|
===========================================
|
|
|
|
The High Precision Event Timer (HPET) hardware follows a specification
|
|
by Intel and Microsoft, revision 1.
|
|
|
|
Each HPET has one fixed-rate counter (at 10+ MHz, hence "High Precision")
|
|
and up to 32 comparators. Normally three or more comparators are provided,
|
|
each of which can generate oneshot interrupts and at least one of which has
|
|
additional hardware to support periodic interrupts. The comparators are
|
|
also called "timers", which can be misleading since usually timers are
|
|
independent of each other ... these share a counter, complicating resets.
|
|
|
|
HPET devices can support two interrupt routing modes. In one mode, the
|
|
comparators are additional interrupt sources with no particular system
|
|
role. Many x86 BIOS writers don't route HPET interrupts at all, which
|
|
prevents use of that mode. They support the other "legacy replacement"
|
|
mode where the first two comparators block interrupts from 8254 timers
|
|
and from the RTC.
|
|
|
|
The driver supports detection of HPET driver allocation and initialization
|
|
of the HPET before the driver module_init routine is called. This enables
|
|
platform code which uses timer 0 or 1 as the main timer to intercept HPET
|
|
initialization. An example of this initialization can be found in
|
|
arch/x86/kernel/hpet.c.
|
|
|
|
The driver provides a userspace API which resembles the API found in the
|
|
RTC driver framework. An example user space program is provided in
|
|
file:samples/timers/hpet_example.c
|