First phase in introducing ACPI support to SN.
In this phase, when running with an ACPI capable PROM,
the DSDT will define the root busses and all SN nodes
(SGIHUB, SGITIO). An ACPI bus driver will be registered
for the node devices, with the acpi_pci_root_driver being
used for the root busses. An ACPI vendor descriptor is
now used to pass platform specific information for both
nodes and busses, eliminating the need for the current
SAL calls. Also, with ACPI support, SN fixup code is no longer
needed to initiate the PCI bus scans, as the acpi_pci_root_driver
does that.

However, to maintain backward compatibility with non-ACPI capable
PROMs, none of the current 'fixup' code can been deleted, though
much restructuring has been done. For example, the bulk of the code
in io_common.c is relocated code that is now common regardless
of what PROM is running, while io_acpi_init.c and io_init.c contain
routines specific to an ACPI or non ACPI capable PROM respectively.

A new pci bus fixup platform vector has been created to provide
a hook for invoking platform specific bus fixup from pcibios_fixup_bus().

The size of io_space[] has been increased to support systems with
large IO configurations.
Signed-off-by: NJohn Keller <jpk@sgi.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.

The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around.  On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).

Where appropriate, an arch may override the generic storage facility and do
something different with the variable.  On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.

Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions.  Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller.  A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.

I've build this code with allyesconfig for x86_64 and i386.  I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.

This will affect all archs.  Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:

	struct pt_regs *old_regs = set_irq_regs(regs);

And put the old one back at the end:

	set_irq_regs(old_regs);

Don't pass regs through to generic_handle_irq() or __do_IRQ().

In timer_interrupt(), this sort of change will be necessary:

	-	update_process_times(user_mode(regs));
	-	profile_tick(CPU_PROFILING, regs);
	+	update_process_times(user_mode(get_irq_regs()));
	+	profile_tick(CPU_PROFILING);

I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().

Some notes on the interrupt handling in the drivers:

 (*) input_dev() is now gone entirely.  The regs pointer is no longer stored in
     the input_dev struct.

 (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking.  It does
     something different depending on whether it's been supplied with a regs
     pointer or not.

 (*) Various IRQ handler function pointers have been moved to type
     irq_handler_t.
Signed-Off-By: NDavid Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)

It turns out msi_ops was simply not enough to abstract the architecture
specific details of msi.  So I have moved the resposibility of constructing
the struct irq_chip to the architectures, and have two architecture specific
functions arch_setup_msi_irq, and arch_teardown_msi_irq.

For simple architectures those functions can do all of the work.  For
architectures with platform dependencies they can call into the appropriate
platform code.

With this msi.c is finally free of assuming you have an apic, and this
actually takes less code.

The helpers for the architecture specific code are declared in the linux/msi.h
to keep them separate from the msi functions used by drivers in linux/pci.h
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Greg KH <greg@kroah.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Abstract portions of the MSI core for platforms that do not use standard
APIC interrupt controllers.  This is implemented through a new arch-specific
msi setup routine, and a set of msi ops which can be set on a per platform
basis.
Signed-off-by: NMark Maule <maule@sgi.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

This patch removes following compile time warnings:

drivers/pci/pci-sysfs.c: In function `pci_read_legacy_io':
drivers/pci/pci-sysfs.c:257: warning: implicit declaration of function `ia64_pci_legacy_read'
drivers/pci/pci-sysfs.c: In function `pci_write_legacy_io':
drivers/pci/pci-sysfs.c:280: warning: implicit declaration of function `ia64_pci_legacy_write'

It also fixes wrong definition of ia64_pci_legacy_write (type of `bus' is not
`pci_dev', but `pci_bus').
Signed-Off-By: NSatoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

On SN2, MMIO writes which are issued from separate processors are not
guaranteed to arrive in any particular order at the IO hardware.  When
performing such writes from the kernel this is not a problem, as a
kernel thread will not migrate to another CPU during execution, and
mmiowb() calls can guarantee write ordering when control of the IO
resource is allowed to move between threads.

However, when MMIO writes can be performed from user space (e.g. DRM)
there are no such guarantees and mechanisms, as the process may
context-switch at any time, and may migrate to a different CPU as part
of the switch.  For such programs/hardware to operate correctly, it is
required that the MMIO writes from the old CPU be accepted by the IO
hardware before subsequent writes from the new CPU can be issued.

The following patch implements this behavior on SN2 by waiting for a
Shub register to indicate that these writes have been accepted.  This
is placed in the context switch-in path, and only performs the wait
when the newly scheduled task changes CPUs.
Signed-off-by: NPrarit Bhargava <prarit@sgi.com>
Signed-off-by: NBrent Casavant <bcasavan@sgi.com>

... and related annotations for amd64 - swiotlb code is shared, but
prototypes are not.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

flush_tlb_all() can be a scaling issue on large SGI Altix systems
since it uses the global call_lock and always executes on all cpus.
When a process enters flush_tlb_range() to purge TLBs for another
process, it is possible to avoid flush_tlb_all() and instead allow
sn2_global_tlb_purge() to purge TLBs only where necessary.

This patch modifies flush_tlb_range() so that this case can be handled
by platform TLB purge functions and updates ia64_global_tlb_purge()
accordingly.  sn2_global_tlb_purge() now calculates the region register
value from the mm argument introduced with this patch.
Signed-off-by: NDean Roe <roe@sgi.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

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!