OFW device tree for PCI bridges and add a new one for PCI Express.
While at it, take advantage of the former for the rman(9) work-
around in jbusppm(4).
- Failing to register as interrupt controller during attach shouldn't
be fatal so just inform about this instead of panicing.
- Disable rerun of the streaming cache as workaround for a silicon bug
of certain Psycho versions.
- Remove the comment regarding lack of newbus'ified bus_dma(9) as being
able to associate a DMA tag with a device would allow to implement
CDMA flushing/syncing in bus_dmamap_sync(9) but that would totally
kill performance. Given that for devices not behind a PCI-PCI bridge
the host-to-PCI bridges also only do CDMA flushing/syncing based on
interrupts there's no additional disadvantage for polling(4) callbacks
in the case schizo(4) has to do the CDMA flushing/syncing but rather a
general problem.
- Don't panic if the power failure, power management or over-temperature
interrupts doesn't exist as these aren't mandatory and not available
with all controllers (not even Psychos). [1]
- Take advantage of KOBJMETHOD_END.
- Remove some redundant variables.
- Add missing const.
PR: 131371 [1]
- Hook up the streaming buffer (not used by iommu(4) by default, yet)
if available and usable. [1]
- Move the message regarding belated registration as interrupt control
under bootverbose as this isn't something the user should worry about.
Tested by: Michael Moll [1]
be fatal so just inform about this instead of panicing.
- Ensure we use the right softc in case the interrupt of a child is
is routed to the companion PBM instead. This hasn't been seen in the
wild so far but given that it's the case for the Schizo interrupts,
handling this situation also for child interrupts as a precaution
seemed a good idea.
- Deal with broken firmware versions which miss child entries in the
ino-bitmap as seen on V880 by belatedly registering as interrupt
controller in schizo_setup_intr(). [1]
- Add missing '\n' when printing the warning regarding Schizo Errata
I-13.
Reported and tested by: Beat Gaetzi [1]
the code for parsing interrupt maps) to PowerPC and reflect their new MI
status by moving them to the shared dev/ofw directory.
This commit also modifies the OFW PCI enumeration procedure on PowerPC to
allow the bus to find non-firmware-enumerated devices that Apple likes to add,
and adds some useful Open Firmware properties (compat and name) to the pnpinfo
string of children on OFW SBus, EBus, PCI, and MacIO links. Because of the
change to PCI enumeration on PowerPC, X has started working again on PPC
machines with Grackle hostbridges.
Reviewed by: marius
Obtained from: sparc64
and XMITS has to be basically done in the same manner as for
the Sabres, i.e. only for devices behind PCI-PCI-bridges and
after a PIO read on the far side of the farest PCI-PCI-bridge.
Given that the Tomatillo documentation mentions no difference
to the Schizo bridges in this regard and this is also still
part of the procedure described Schizo documentation this
seems about right so adjust accordingly (the unconditional
CDMA flushing/syncing previously done was based on how Linux
behaves).
- Implement CDMA flushing/syncing for Schizo version >= 5,
which requires the workaround described in Schizo Errata I-23.
According to Schizo Errata I-13 it's just unusable with
version < 5 though. [1]
- Don't register the Schizo streaming buffer for now until it's
usage is sorted out according to the erratas.
- Register our interrupt filters with the revived INTR_FAST so
they these interrupts can even interrupt filters of device
drivers as necessary.
- Remove the comment regarding lack of newbus'ified bus_dma(9)
as being able to associate a DMA tag with a device would
allow to implement CDMA flushing/syncing in bus_dmamap_sync(9)
but that would totally kill performance. Given that for devices
not behind a PCI-PCI bridge the host-to-PCI bridges also only
do CDMA flushing/syncing based on interrupts there's no
additional disadvantage for polling(4) callbacks in the case
schizo(4) has to do the CDMA flushing/syncing but rather a
general problem.
Reported by: Michael Moll [1]
while doing the block store workaround so we restore the correct
floating-point registers state in case of nested floating-point
operations resulting from nested interrupts. This allows the
VIS-based block copy/zero functions to be used on machines
requiring this workaround. Alternatively, we could take care of
saving the floating-point registers here, which would be more
inefficiently though and also involves turning off interrupts.
- It turns out that the SCZ_PCI_DMA_SYNC register doesn't work
like the TOMXMS_PCI_DMA_SYNC_PEND one (but more like the
corresponding register in of Hummingbird and Sabre bridges)
and writing the INO of the respective device to it causes a
Safari bus error. However, due to the Schizo errata I-23,
SCZ_PCI_DMA_SYNC can't be used as intended either, so remove
consistent DMA syncing for Schzio bridges for now, which means
that add-on cards with non-"sun4u compliant" (whatever that
means exactly) PCI-PCI-bridges should be avoided until the
proper workaround is implemented. [1]
Reported by: Michael Moll [1]
JBus to PCI 2.2 bridges. In theory, this driver should also handle
`XMITS' Fireplane/Safari to PCI-X bridges but due to lack of access
to such hardware, support for these hasn't be fleshed out, yet.
could trigger an error interrupt that we can't actually to do anything
against as soon as enabling the error handlers.
While at it don't bother about writing only to the write-one-to-clear
bits when clearing error bits.
the latency based on the Min_Gnt register so use the algorithm found
in OpenSolaris as they probably know how to interpret the value Sun
puts into these registers (previously, the latency calculated for
66MHz was most likely wrong) and for bridges additionally set up the
secondary latency register. Also set up the bridge control register
the way it's done in OpenSolaris. As the latency register don't apply
to PCI-Express and the bridge control setup wasn't tested on sun4v
(besides most likely not being needed), expand the #ifndef SUN4V
accordingly.
MFC after: 3 days
counter-timer timecounter so the associated SYSCTL nodes don't clash on
machines having multiple U2P and U2S bridges as well as establishing a
clear mapping between these bridges and their timecounter device.
- Don't bother setting up a "nice" name for the IOMMU, just use the name
returned by device_get_nameunit(9), too.
- Fix some minor style(9) bugs.
- Use __FBSDID in counter.c
MFC after: 1 week
infrastructure. Its only consumer ever was sio(4) and thus was
unused on sparc64 since removing the last traces of sio(4) in
sparc64 configuration files in favor for uart(4) over three
years ago. If similar functionality is required again it should
be brought back as an MD intr_pending() which works for all
busses by using for example interrupt controller hooks.
don't send and EOI which works like on amd64/i386 and blocks all
interrupts on the relevant interrupt controller.
o Replace the post_filter and post_inthread hooks registered when
creating the interrupt events with just ic_clear as on sparc64 we
don't need to do any disable->EOI->enable dance to unblock all but
the relevant interrupt while running the filter or handler; just
not clearing the interrupt already has the same effect.
o Merge from amd64/i386:
- Split the intr_table_lock into an sx lock used for most things,
and a spin lock to protect intrcnt_index.
- Add support for binding interrupts to CPUs, including for the
bus_bind_intr(9) interface, a assign_cpu hook and initially
shuffling interrupts arround in a round-robin fashion.
Reviewed by: jhb
MFC after: 1 month
have separate configuration spaces so by definition they implement
different PCI domains. Thus change psycho(4) to use PCI domains
instead of reenumerating all PCI busses so they have globally unique
bus numbers and drop support for reenumerating busses in the OFW PCI
code.
According to CVS history reenumeration was also required in order to
get some E450 to boot but given that no other open source kernel
changes the PCI bus numbers assigned by the firmware I believe the
real problem was that the old code used the bus number as the device
number for the PCI busses and unlike most of the other machines the
firmwares of the problematic ones don't use disjoint PCI bus numbers
across the host-PCI-bridges.
MFC after: 1 month
for that argument. This will allow DDB to detect the broad category of
reason why the debugger has been entered, which it can use for the
purposes of deciding which DDB script to run.
Assign approximate why values to all current consumers of the
kdb_enter() interface.
is required by the X.Org PCI domains code and additionally needs
a workaround for Hummingbird and Sabre bridges as these don't
allow their config headers to be read at any width, which is an
unusual behavior.
- In psycho(4) take advantage of DEFINE_CLASS_0 and use more
appropriate types for some softc members.
MFC after: 3 days
support machines having multiple independently numbered PCI domains
and don't support reenumeration without ambiguity amongst the
devices as seen by the OS and represented by PCI location strings.
This includes introducing a function pci_find_dbsf(9) which works
like pci_find_bsf(9) but additionally takes a domain number argument
and limiting pci_find_bsf(9) to only search devices in domain 0 (the
only domain in single-domain systems). Bge(4) and ofw_pcibus(4) are
changed to use pci_find_dbsf(9) instead of pci_find_bsf(9) in order
to no longer report false positives when searching for siblings and
dupe devices in the same domain respectively.
Along with this change the sole host-PCI bridge driver converted to
actually make use of PCI domain support is uninorth(4), the others
continue to use domain 0 only for now and need to be converted as
appropriate later on.
Note that this means that the format of the location strings as used
by pciconf(8) has been changed and that consumers of <sys/pciio.h>
potentially need to be recompiled.
Suggested by: jhb
Reviewed by: grehan, jhb, marcel
Approved by: re (kensmith), jhb (PCI maintainer hat)
33MHz for calculating the latency timer values for its children.
Inspired by NetBSD doing the same and Linux as well as OpenSolaris
using a similar approach.
While at it rename a variable and change its type to be more
appropriate fuer values of PCI properties so the variable can be
more easily reused.
- Initialize the cache line size register of PCI devices to a
legal value; the cache line size is limited to 64 bytes by the
Fireplane/Safari, JBus and UPA interconnection busses. Setting
it to an unsupported value caused bad performance at least with
GEM as it causes them to not do cache line bursts and to not
issue cache line commands on the PCI bus.
Approved by: re (kensmith)
MFC after: 1 week
with the INTR_FILTER-enabled MI code. Basically this consists of
registering an interrupt controller (of which there can be multiple
and optionally different ones either per host-to-foo bridge or shared
amongst host-to-foo bridges in any one machine) along with an interrupt
vector as specific argument for all the interrupt vectors used by a
given host-to-foo bridge (roughly similar to registering interrupt
sources on amd64 and i386), providing functions to enable, clear and
disable the interrupts of the children beneath the bridge.
This also includes:
- No longer entering a critical section in tl0_intr() and tl1_intr()
for executing interrupt handlers but rather let the handlers enter
it themselves so in the case of intr_event_handle() we don't enter
a nested critical section.
- Adding infrastructure for binding delivery of interrupt vectors to
specific CPUs which later on can be interfaced with the code from
amd64/i386 for binding interrupts to specific CPUs.
- Getting rid of the wrapper hack introduced along the lines of the
API changes for INTR_FILTER which as a side-effect caused interrupts
associated with ithread handlers only to get the elevated priority
of those associated with filters ("fast handlers") (this removes the
hack also in the non-INTR_FILTER case).
- Disabling (by not clearing) an interrupt in the interrupt controller
until all associated handlers have been executed, which is crucial
for the typical locking strategy of NIC drivers in order to work
correctly in case of shared interrupts. This was a more or less
theoretical problem on sparc64 though, as shared interrupts are
rather uncommon there except for the on-board SCCs and UARTs.
Note that due to the behavior of at least of some of the interrupt
controllers used on sparc64 an enable+EOI instead of a disable+EOI
approach (as implied by the INTR_FILTER MI code and implemented on
other architectures) is used as the latter can cause lost interrupts
or in the worst case interrupt starvation.
o Correct a typo in sbus_alloc_resource() which caused (pass-through)
allocations to only work down to the grandchildren of the bus, which
wasn't a real problem so far as we don't support any devices which are
great-grandchildren or greater of a U2S bridge, yet.
o In fhc(4) use bus_{read,write}_4() instead of bus_space_{read,write}_4()
in order to get rid of sc_bh and sc_bt in the fhc_softc. Also get rid
of some other unneeded members in fhc_softc.
Reviewed by: marcel (earlier version)
Approved by: re (kensmith)
instead of per IOMMU, so we no longer need to program all of them
identically in systems having multiple IOMMUs. This continues the
rototilling of the nexus(4) done about 5 months ago, which amongst
others changed nexus(4) and the drivers for host-to-foo bridges
to provide bus_get_dma_tag methods, allowing to handle DMA tags in
a hierarchical way and to link them with devices.
This still doesn't move the silicon bug workarounds for Sabre (and
in the uncommitted schizo(4) for Tomatillo) bridges into special
bus_dma_tag_create() and bus_dmamap_sync() methods though, as w/o
fully newbus'ified bus_dma_tag_create() and bus_dma_tag_destroy()
this still requires too much hackery, i.e. per-child parent DMA
tags in the parent driver.
- Let the host-to-foo drivers supply the maximum physical address
of the IOMMU accompanying the bridges. Previously iommu(4) hard-
coded an upper limit of 16GB, which actually only applies to the
IOMMUs of the Hummingbird and Sabre bridges. The Psycho variants
as well as the U2S in fact can can translate to up to 2TB, i.e.
translate to 41-bit physical addresses. According to the recently
available Tomatillo documentation these bridges even translate to
43-bit physical addresses and hints at the Schizo bridges doing
43 bits as well.
This fixes the issue the FreeBSD 6.0 todo list item "Max RAM on
sparc64" was refering to and pretty much obsoletes the lack of
support for bounce buffers on sparc64.
Thanks to Nathan Whitehorn for pointing me at the Tomatillo manual.
Approved by: re (kensmith)
allowing the driver for the host-PCI-bridge to indicate that
reenumeration of the PCI busses isn't supported by returning
-1 instead of a valid PCI bus number. This is needed in order
support both Tomatillo, which don't support reenumeration and
thus are apparently intended to be used for independently
numbered PCI domains only, and Psycho bridges, whose busses
need to be reenumerated on at least some E450, without the
#ifndef currently used for sun4v in order to support multiple
independently PCI domains. The actual allocation/incrementation
of the PCI bus numbers is now done in psycho(4), though it
no longer establish a mapping between bus numbers and device
nodes like ofw_pci_alloc_busno() did as that functionality
wasn't used (but can easily brought back if really needed).
The now no longer used sys/sparc64/pci/ofw_pci.c is also
removed from sys/conf/files.sun4v as ofw_pci_alloc_busno()
wasn't used there in the first place.
- In ofw_pci_default_{adjust_busrange,intr_pending}() sanity
check that the device has a parent before passing it on.
- Make psycho_softcs static to sys/sparc64/pci/psycho.c as
it's not used outside of that module.
- In sys/sparc64/pci/ofw_pcib_subr.c remove the superfluous
inclusion of opt_global.h and correct the debug output for
adjusting the subordinate bus number.
instead of using the PCI bus number, like it's already done for
sun4v in order to deal properly with independently numbered PCI
domains which can't be reenumerated (in the case of sun4u f.e.
Tomatillo bridges). For machines where we need to reenumerate
all PCI busses this change obviously introduces the theoretical
cosmetic problem that the device number of the PCI bus no longer
equals to its PCI bus number. In practice this doesn't happen
as both are assigned linearly and in parallel.
allowing it to be a filter/"fast" handler. Locking the interrupt
handlers with a spin lock is mainly a requirement in schizo(4)
but as we ought to register the spin lock anyway it should not
hurt to take advantage of it in psycho(4).
- Pass both a driver_filter_t and a driver_intr_t argument to
psycho_set_intr(), allowing to get rid of the FAST interrupt
flag hack.
- Don't register the over-temperature interrupt handler as filter/
"fast" handler so shutdown_nice() can acquire the process lock.
- Use bus_{read,write}_8() instead of bus_space_{read,write}_8()
in order to get rid of sc_bushandle and sc_bustag in the softc.
- Correct the debug output for adjusting the subordinate bus number.
- Remove the banal and outdated above psycho_filter_stub().
- Fix some white space nits.
iommureg.h (which already began to bitrot) and iommuvar.h from the
sun4v source and adjust some of the source which is shared between
sparc64 and sun4v as appropriate.
sun4v nexus(4) in turn is based on):
o Change nexus(4) to manage the resources of its children so the
respective device drivers don't need to figure them out of OFW
themselves.
o Change nexus(4) to provide the ofw_bus KOBJ interface instead of
using IVARs for supplying the OFW node and the subset of standard
properties of its children. Together with the previous change this
also allows to fully take advantage of newbus in that drivers like
fhc(4), which attach on multiple parent busses, no longer require
different bus front-ends as obtaining the OFW node and properties
as well as resource allocation works the same for all supported
busses. As such this change also is part 4/4 of allowing creator(4)
to work in USIII-based machines as it allows this driver to attach
on both nexus(4) and upa(4). On the other hand removing these IVARs
breaks API compatibility with the powerpc nexus(4) but which isn't
that bad as a) sparc64 currently doesn't share any device driver
hanging off of nexus(4) with powerpc and b) they were no longer
compatible regarding OFW-related extensions at the pci(4) level
since quite some time.
o Provide bus_get_dma_tag methods in nexus(4) and its children in
order to handle DMA tags in a hierarchical way and get rid of the
sparc64_root_dma_tag kludge. Together with the previous two items
this changes also allows to completely get rid of the nexus(4)
IVAR interface. It also includes:
- pushing the constraints previously specified by the nexus_dmatag
down into the DMA tags of psycho(4) and sbus(4) as it's their
IOMMUs which induce these restrictions (and nothing at the
nexus(4) or anything that would warrant specifying them there),
- fixing some obviously wrong constraints of the psycho(4) and
sbus(4) DMA tags, which happened to not actually be used with
the sparc64_root_dma_tag kludge in place and therefore didn't
cause problems so far,
- replacing magic constants for constraints with macros as far
as it is obvious as to where they come from.
This doesn't include taking advantage of the newbus way to get
the parent DMA tags implemented by this change in order to divorce
the IOTSBs of the PCI and SBus IOMMUs or for implementing the
workaround for the DMA sync bug in Sabre (and Tomatillo) bridges,
yet, though.
o Get rid of the notion that nexus(4) (mostly) reflects an UPA bus
by replacing ofw_upa.h and with ofw_nexus.h (which was repo-copied
from ofw_upa.h) and renaming its content, which actually applies to
all of Fireplane/Safari, JBus and UPA (in the host bus case), as
appropriate.
o Just use M_DEVBUF instead of a separate M_NEXUS malloc type for
allocating the device info for the children of nexus(4). This is
done in order to not need to export M_NEXUS when deriving drivers
for subordinate busses from the nexus(4) class.
o Use the DEFINE_CLASS_0() macro to declare the nexus(4) driver so
we can derive subclasses from it.
o Const'ify the nexus_excl_name and nexus_excl_type arrays as well
as add 'associations' and 'rsc', which are pseudo-devices without
resources and therefore of no real interest for nexus(4), to the
former.
o Let the nexus(4) device memory rman manage the entire 64-bit address
space instead of just the UPA_MEMSTART to UPA_MEMEND subregion as
Fireplane/Safari- and JBus-based machines use multiple ranges,
which can't be as easily divided as in the case of UPA (limiting
the address space only served for sanity checking anyway).
o Use M_WAITOK instead of M_NOWAIT when allocating the device info
for children of nexus(4) in order to give one less opportunity
for adding devices to nexus(4) to fail.
o While adapting the drivers affected by the above nexus(4) changes,
change them to take advantage of rman_get_rid() instead of caching
the RIDs assigned to allocated resources, now that the RIDs of
resources are correctly set.
o In iommu(4) and nexus(4) replace hard-coded functions names, which
actually became outdated in several places, in panic strings and
status massages with __func__. [1]
o Use driver_filter_t in prototypes where appropriate.
o Add my copyright to creator(4), fhc(4), nexus(4), psycho(4) and
sbus(4) as I changed considerable amounts of these drivers as well
as added a bunch of new features, workarounds for silicon bugs etc.
o Fix some white space nits.
Due to lack of access to Exx00 hardware, these changes, i.e. central(4)
and fhc(4), couldn't be runtime tested on such a machine. Exx00 are
currently reported to panic before trying to attach nexus(4) anyway
though.
PR: 76052 [1]
Approved by: re (kensmith)
and friends along with all hacks required to implement them. None of
the drivers currently built (as part of GENERIC, LINT or modules) on
sparc64 or sun4v and none of those we might want to use there in
future uses them, AFAICT there actually never was a driver hooked up
to the sparc64 or sun4v build that correctly used these functions
(and it looks like that due to a bug read{b,w,l}()/write{b,w,l}() and
the other functions working on a memory handle never actually worked on
sun4v). All they ever were good for on sparc64 and sun4v was erroneously
dragging in dependencies on isa(4) in drivers like f.e. dpt(4), si(4)
and syscons(4) in source files that supposedly were bus-neutral and
hiding issues with drivers like f.e. ng_bt3c(4) that used these
functions with busses other than isa(4) and therefore couldn't work on
these platforms.
- Clear the PCI AFSR and status error bits as previous errors still
might be indicated.
- Set up the PCI control and diagnostic registers according to the
capabilities, workarounds, etc of/for specific revisions of the
supported bridges. This includes no longer setting Hummingbird-/
Sabre-specific bits in the PCI control register but preserving
what the firmware has initialized them to like OpenSolaris does.
Previously we were setting these bits according to the example in
the Sabre documentation, which I doubt is appropriate for all
Sabre based designs and especially not for Hummingbirds. This
also includes not enabling bus parking unless the firmware tells
us to.
- Set the PCI latency timer register as this isn't always done by
the firmware.
o Remove a redundant argument from psycho_set_intr() and in this
function check the return value of bus_setup_intr(). [2]
o Let psycho_setup_intr() return ENOMEM instead of 0 when it can't
allocate memory for the interrupt wrapper stub and EINVAL instead
of 0 if it can't find the interrupt vector in the interrupt map.
o Add a workaround for a bug of the Sabre-APB-combination where it
doesn't drain DMA write data for devices behind additional PCI-PCI
bridges underneath the APB PCI-PCI bridge. This workaround (do
things necessary in order to achieve a manual drain when coherency
is required) is currently implemented in psycho_setup_intr() and
psycho_intr_stub() (for easy MFC'ing) and therefore is only applied
for interrupt handlers. This should be moved to psycho(4)-specific
bus_dma_tag_create() and bus_dmamap_sync() methods, respectively,
once this driver is converted to make use of BUS_GET_DMA_TAG(), so
the workaround is also applied for polling(4) callbacks. [3]
o Fix some minor style issues.
Info from: OpenSolaris [1]
Info from: Linux, OpenBSD, OpenSolaris [3]
Suggested by: Coverity Prevent (CID 682) [2]
MFC after: 1 month
firmware (mainly 'pmu' and its 'lomp' dupe found in a couple of
later USII{e,i}-based machines) by checking whether a device with
the same triple of bus number, slot and function already has been
added. This is the simple yet effective approach introduced in
OpenBSD some time ago, but which has the flaw that it assumes
that the device and its dupe(s) found in the OFW device tree are
equal or at least the one encountered first is in some way the
more important one (this is the case with 'pmu' and 'lomp'; the
'pmu' node has couple of properties and children while the 'lomp'
one misses most of these). If there's ever a device/dupe pair
where we don't encounter the more important node first, we'll
probably need to introduce a quirk list in order to add the
desired device but prevent its dupe(s) from being added.
MFC after: 1 week
and resume methods so these events propagate through the device driver
hierarchy.
- In dma(4) enable the chaining of the DMA engine interrupt handler for
the LANCE devices via a dma_setup_intr(). This was commented out before
as I was unsure whether I'd use it but this is probably cleaner than
fiddling with the DMA engine interrupt in the LANCE driver directly.
- In ebus_setup_dinfo() free 'intrs' instead of 'reg' twice in case
setting up a child fails due to routing one of its interrupts fails. [1]
Found by: Coverity Prevent [1]
MFC after: 3 days
various pcib drivers to use their own private devclass_t variables for
their modules.
- Use the DEFINE_CLASS_0() macro to declare drivers for the various pcib
drivers while I'm here.
to search for a specific extended capability. If the specified capability
is found for the given device, then the function returns success and
optionally returns the offset of that capability. If the capability is
not found, the function returns an error.
from sys/sparc64/include/ofw_upa.h to sys/sparc64/pci/ofw_pci.h and
rename them to struct ofw_pci_ranges and OFW_PCI_RANGE_* respectively.
This ranges struct only applies to host-PCI bridges but no to other
bridges found on UPA. At the same time it applies to all host-PCI
bridges regardless of whether the interconnection bus is Fireplane/
Safari, JBus or UPA.
- While here rename the PCI_CS_* macros in sys/sparc64/pci/ofw_pci.h
to OFW_PCI_CS_* in order to be consistent and change this header to
use uintXX_t instead of u_intXX_t.
the bridge (PCI bus A or B) we are attaching to rather than registering
both handlers at once when attaching to the first half we encounter.
This is a bit cleaner as it corresponds to which PCI bus error interrupt
actually is assigned to the respective half by the OFW and allows to
collapse both PCI bus error interrupt handlers into one function easily.
- Use the actual RID of the respective interrupt resource as index into
sc_irq_res and also use it when allocating the resource. For now this
is a bit cleaner and will be mandatory later on.
- According to OpenSolaris the spare hardware interrupt is used as the
over-temperature interrupt in systems with Psycho bridges. Unlike as
with the SBus-based workstations I didn't manage to trigger it when
covering the fan outlets of an U60 but better be safe than sorry and
register a handler anyway.
MFC after: 1 month
