HPET to steal IRQ0 from i8254 and IRQ8 from RTC timers. It can be suitable
for HPETs without FSB interrupts support, as it gives them two unshared
IRQs. It allows them to provide one per-CPU event timer on dual-CPU system,
that should be suitable for further tickless kernels.
To enable it, such lines may be added to /boot/loader.conf:
hint.atrtc.0.clock=0
hint.attimer.0.clock=0
hint.hpet.0.legacy_route=1
writing event timer drivers, for choosing best possible drivers by machine
independent code and for operating them to supply kernel with hardclock(),
statclock() and profclock() events in unified fashion on various hardware.
Infrastructure provides support for both per-CPU (independent for every CPU
core) and global timers in periodic and one-shot modes. MI management code
at this moment uses only periodic mode, but one-shot mode use planned for
later, as part of tickless kernel project.
For this moment infrastructure used on i386 and amd64 architectures. Other
archs are welcome to follow, while their current operation should not be
affected.
This patch updates existing drivers (i8254, RTC and LAPIC) for the new
order, and adds event timers support into the HPET driver. These drivers
have different capabilities:
LAPIC - per-CPU timer, supports periodic and one-shot operation, may
freeze in C3 state, calibrated on first use, so may be not exactly precise.
HPET - depending on hardware can work as per-CPU or global, supports
periodic and one-shot operation, usually provides several event timers.
i8254 - global, limited to periodic mode, because same hardware used also
as time counter.
RTC - global, supports only periodic mode, set of frequencies in Hz
limited by powers of 2.
Depending on hardware capabilities, drivers preferred in following orders,
either LAPIC, HPETs, i8254, RTC or HPETs, LAPIC, i8254, RTC.
User may explicitly specify wanted timers via loader tunables or sysctls:
kern.eventtimer.timer1 and kern.eventtimer.timer2.
If requested driver is unavailable or unoperational, system will try to
replace it. If no more timers available or "NONE" specified for second,
system will operate using only one timer, multiplying it's frequency by few
times and uing respective dividers to honor hz, stathz and profhz values,
set during initial setup.
measured interval as upper bound. It should be more precise then just
assuming hz/2. For idle CPU it should be quite precise, for busy - not
worse then before.
state lower than the lowest one supported by the current CPU. This closes
some races with changes to the hw.acpi.cpu_cx_lowest sysctl while Cx
states for individual CPUs were changing (e.g. unplugging the AC adapter
of a laptop) that could result in panics.
Submitted by: Giovanni Trematerra
Tested by: David Demelier demelier dot david of gmail
MFC after: 3 days
via %s
Most of the cases looked harmless, but this is done for the sake of
correctness. In one case it even allowed to drop an intermediate buffer.
Found by: clang
MFC after: 2 week
device, make sure we have no real HPET device entry with same ID.
As side effect, it potentially allows several HPETs to be attached.
Use first of them for timecounting, rest (if ever present) could later
be used as event sources.
Setting the new sysctl MIB "debug.acpi.enable_debug_objects" to a non-zero
value enables us to print Debug object when something is written to it.
- Allow users to disable interpreter slack mode. Setting the new tunable
"debug.acpi.interpreter_slack" to zero disables some workarounds for common
BIOS mistakes and enables strict ACPI implementations by the specification.
It is belived that that pass s not needed anymore.
Specifically it is not required now for the reasons that were given
in the removed comment.
Discussed with: jhb
MFC after: 4 weeks
Some current systems dynamically load SSDT(s) when _PDC/_OSC method
of Processor is evaluated. Other devices in ACPI namespace may access
objects defined in the dynamic SSDT. Drivers for such devices might
have to have a rather high priority, because of other dependencies.
Good example is acpi_ec driver for EC.
Thus we attach to Processors as early as possible to load the SSDTs
before any other drivers may try to evaluate control methods.
It also seems to be a natural order for a processor in a device
hierarchy.
On the other hand, some child devices on acpi cpu bus need to access
other system resources like PCI configuration space of chipset devices,
so they need to be probed and attached rather late.
For this reason we probe and attach the cpu bus at
SI_SUB_CONFIGURE:SI_ORDER_MIDDLE SYSINIT level.
In the future this could be done more elegantly via multipass.
Please note that acpi drivers that might access ACPI namespace from
device_identify will do that before _PDC/_OSC of Processors are evaluated.
Legacy cpu driver is not affected by this change.
PR: kern/142561 (in part)
Reviewed by: jhb
Silence from: acpi@
MFC after: 5 weeks
_PDC was deprecated in favor of _OSC long time ago, but it
seems that they still peacefully coexist and in some case
only _PDC is present.
Still _OSC provides a reacher interface and is capable to
report back its status.
If the status is non-zero, then report it, we may find
it useful to understand what firmware expects from OS.
Also clean up some comments that became less useful over time.
Reviewed by: njl, jhb, rpaulo
MFC after: 3 weeks
Also, account for a quirk of AMD/ATI HPET which reports number of timers
instead of id of the last timer as manadated by the specification.
Currently this has no effect on functionality but in the future we may
make actual use of the HPET timers, not only of its timecounter.
MFC after: 2 weeks
This is not only a prudent thing to do, but also makes sure that probe
method is not confused by non-NULL 'private', if the previous attach
attempt fails for any reason.
PR: kern/142561
Tested by: Alex Goncharov <alex-goncharov@comcast.net>
MFC after: 4 days
o acpi_hpet: auto-added 'wildcard' devices can be identified by
non-NULL handle attribute.
o acpi_ec: auto-add 'wildcard' devices can be identified by
unset (NULL) private attribute.
o acpi_cpu: use private instead of magic to store cpu id.
Reviewed by: jhb
Silence from: acpi@
MFC after: 2 weeks
X-MFC-Note: perhaps the ivar should stay for ABI stability
sysctl lock. The 'video' lock now protects the 'bus' of video output
devices attached to a graphics adapter. It is used when iterating over
the list of outputs, etc. The 'video_output' lock is used to lock the
output-specific data similar to a driver lock for the individual video
outputs.
MFC after: 2 weeks
startup and genericize it so it can be reused to map other tables as well:
- Add a routine to walk a list of ACPI subtables such as those used in the
APIC and SRAT tables in the MI acpi(4) driver.
- Move the routines for mapping and unmapping an ACPI table as well as
mapping the RSDT or XSDT and searching for a table with a given signature
out into acpica_machdep.c for both amd64 and i386.
BIOS-enumerated devices:
- Assume a device is a match if the memory and I/O ports match even if the
IRQ or DRQ is wrong or missing. Some BIOSes don't include an IRQ for
the atrtc device for example.
- Add a hack to better match floppy controller devices. Many BIOSes do not
include the starting port of the floppy controller listed in the hints
(0x3f0) in the resources for the device. So far, however, all the BIOS
variations encountered do include the 'port + 2' resource (0x3f2), so
adjust the matching for "fdc" devices to look for 'port + 2'.
Reviewed by: imp
MFC after: 3 days
The newbus lock is responsible for protecting newbus internIal structures,
device states and devclass flags. It is necessary to hold it when all
such datas are accessed. For the other operations, softc locking should
ensure enough protection to avoid races.
Newbus lock is automatically held when virtual operations on the device
and bus are invoked when loading the driver or when the suspend/resume
take place. For other 'spourious' operations trying to access/modify
the newbus topology, newbus lock needs to be automatically acquired and
dropped.
For the moment Giant is also acquired in some key point (modules subsystem)
in order to avoid problems before the 8.0 release as module handlers could
make assumptions about it. This Giant locking should go just after
the release happens.
Please keep in mind that the public interface can be expanded in order
to provide more support, if there are really necessities at some point
and also some bugs could arise as long as the patch needs a bit of
further testing.
Bump __FreeBSD_version in order to reflect the newbus lock introduction.
Reviewed by: ed, hps, jhb, imp, mav, scottl
No answer by: ariff, thompsa, yongari
Tested by: pho,
G. Trematerra <giovanni dot trematerra at gmail dot com>,
Brandon Gooch <jamesbrandongooch at gmail dot com>
Sponsored by: Yahoo! Incorporated
Approved by: re (ksmith)
