The SGI PCI-RT card, based on the SGI IOC4 chip, will be made available on
Altix XE (x86_64) platforms in the near future.  As such it is now a
misnomer for the IOC4 base device driver to live under drivers/sn, and
would complicate builds for non-SN2.

This patch moves the IOC4 base driver code from drivers/sn to drivers/misc,
and updates the associated Makefiles and Kconfig files to allow building on
non-SN2 configs.  Due to the resulting change in link order, it is now
necessary to use late_initcall() for IOC4 subdriver initialization.

[akpm@osdl.org: __udivdi3 fix]
[akpm@osdl.org: fix default in Kconfig]
Acked-by: NPat Gefre <pfg@sgi.com>
Acked-by: NJeremy Higdon <jeremy@sgi.com>
Signed-off-by: NBrent Casavant <bcasavan@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

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)

ioremap must be balanced by an iounmap and failing to do so can result
in a memory leak.
Signed-off-by: NAmol Lad <amol@verismonetworks.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Brent Casavant <bcasavan@sgi.com>
Cc: Pat Gefre <pfg@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

There are three different IO cards which an SGI IOC4 controller may find
itself on.  One of these variants does not bring out the IDE and serial
signals, so we need to disable attaching the corresponding IOC4 subdrivers
to such cards.

Cleans up message clutter emitted during device probing.
Signed-off-by: NBrent Casavant <bcasavan@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Add rs422 support to the Altix ioc4 serial driver.
Signed-off-by: NPatrick Gefre <pfg@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Get rid of the local 'flip' variable and no need to 'trim' the buffer.
Signed-off-by: NPatrick Gefre <pfg@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Serial drivers in general should not write uart_info->flags - they're
private to serial_core.  Serial drivers have no need to fiddle with
tty->alt_speed, nor manipulate TTY_IO_ERROR in tty->flags.  Fix the
ioc4 serial driver for both these points by simply removing the
offending code.

Acked-by: pfg@sgi.com
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The API and code have been through various bits of initial review by
serial driver people but they definitely need to live somewhere for a
while so the unconverted drivers can get knocked into shape, existing
drivers that have been updated can be better tuned and bugs whacked out.

This replaces the tty flip buffers with kmalloc objects in rings. In the
normal situation for an IRQ driven serial port at typical speeds the
behaviour is pretty much the same, two buffers end up allocated and the
kernel cycles between them as before.

When there are delays or at high speed we now behave far better as the
buffer pool can grow a bit rather than lose characters. This also means
that we can operate at higher speeds reliably.

For drivers that receive characters in blocks (DMA based, USB and
especially virtualisation) the layer allows a lot of driver specific
code that works around the tty layer with private secondary queues to be
removed. The IBM folks need this sort of layer, the smart serial port
people do, the virtualisers do (because a virtualised tty typically
operates at infinite speed rather than emulating 9600 baud).

Finally many drivers had invalid and unsafe attempts to avoid buffer
overflows by directly invoking tty methods extracted out of the innards
of work queue structs. These are no longer needed and all go away. That
fixes various random hangs with serial ports on overflow.

The other change in here is to optimise the receive_room path that is
used by some callers. It turns out that only one ldisc uses receive room
except asa constant and it updates it far far less than the value is
read. We thus make it a variable not a function call.

I expect the code to contain bugs due to the size alone but I'll be
watching and squashing them and feeding out new patches as it goes.

Because the buffers now dynamically expand you should only run out of
buffering when the kernel runs out of memory for real.  That means a lot of
the horrible hacks high performance drivers used to do just aren't needed any
more.

Description:

tty_insert_flip_char is an old API and continues to work as before, as does
tty_flip_buffer_push() [this is why many drivers dont need modification].  It
does now also return the number of chars inserted

There are also

tty_buffer_request_room(tty, len)

which asks for a buffer block of the length requested and returns the space
found.  This improves efficiency with hardware that knows how much to
transfer.

and tty_insert_flip_string_flags(tty, str, flags, len)

to insert a string of characters and flags

For a smart interface the usual code is

    len = tty_request_buffer_room(tty, amount_hardware_says);
    tty_insert_flip_string(tty, buffer_from_card, len);

More description!

At the moment tty buffers are attached directly to the tty.  This is causing a
lot of the problems related to tty layer locking, also problems at high speed
and also with bursty data (such as occurs in virtualised environments)

I'm working on ripping out the flip buffers and replacing them with a pool of
dynamically allocated buffers.  This allows both for old style "byte I/O"
devices and also helps virtualisation and smart devices where large blocks of
data suddenely materialise and need storing.

So far so good.  Lots of drivers reference tty->flip.*.  Several of them also
call directly and unsafely into function pointers it provides.  This will all
break.  Most drivers can use tty_insert_flip_char which can be kept as an API
but others need more.

At the moment I've added the following interfaces, if people think more will
be needed now is a good time to say

 int tty_buffer_request_room(tty, size)

Try and ensure at least size bytes are available, returns actual room (may be
zero).  At the moment it just uses the flipbuf space but that will change.
Repeated calls without characters being added are not cumulative.  (ie if you
call it with 1, 1, 1, and then 4 you'll have four characters of space.  The
other functions will also try and grow buffers in future but this will be a
more efficient way when you know block sizes.

 int tty_insert_flip_char(tty, ch, flag)

As before insert a character if there is room.  Now returns 1 for success, 0
for failure.

 int tty_insert_flip_string(tty, str, len)

Insert a block of non error characters.  Returns the number inserted.

 int tty_prepare_flip_string(tty, strptr, len)

Adjust the buffer to allow len characters to be added.  Returns a buffer
pointer in strptr and the length available.  This allows for hardware that
needs to use functions like insl or mencpy_fromio.
Signed-off-by: NAlan Cox <alan@redhat.com>
Cc: Paul Fulghum <paulkf@microgate.com>
Signed-off-by: NHirokazu Takata <takata@linux-m32r.org>
Signed-off-by: NSerge Hallyn <serue@us.ibm.com>
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Signed-off-by: NJohn Hawkes <hawkes@sgi.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Various small mods for the Altix ioc4 serial driver - mostly cleanup:
- remove UIF_INITIALIZED usage
- use the 'lock' from uart_port
- better multiple card support
Signed-off-by: NPatrick Gefre <pfg@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This change removes a bogus error message from the IOC4 serial driver
interrupt handler.

This error message is bogus for two reasons.  First, it can never occur
given that current code takes care to initialize IOC4 in such a way that
these "unknown" interrupts could never occur.  Second, this code fails to
take into account that other drivers can share the IOC4 interrupt mechanism
through SA_SHIRQ, and thus this driver is not in-fact "all-knowing".

Finally, this error message triggers every time some "unknown" interrupt
occurs -- it's not rate limited or repetition limited in any way, thereby
effectively denying use of the console device.  Given its bogosity in the
first place, it's best to just get rid of it entirely.
Acked-by: NPat Gefre <pfg@sgi.com>
Signed-off-by: NBrent Casavant <bcasavan@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Several hardware features of SGI's IOC4 I/O controller chip require
timing-related driver calculations dependent upon the PCI bus speed.  This
patch enables the core IOC4 driver code to detect the actual bus speed and
store a value that can later be used by the IOC4 subdrivers as needed.
Signed-off-by: NBrent Casavant <bcasavan@sgi.com>
Acked-by: NPat Gefre <pfg@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This series of patches reworks the configuration and internal structure
of the SGI IOC4 I/O controller device drivers.

These changes are motivated by several factors:

- The IOC4 chip PCI resources are of mixed use between functions (i.e.
  multiple functions are handled in the same address range, sometimes
  within the same register), muddling resource ownership and initialization
  issues.  Centralizing this ownership in a core driver is desirable.

- The IOC4 chip implements multiple functions (serial, IDE, others not
  yet implemented in the mainline kernel) but is not a multifunction
  PCI device.  In order to properly handle device addition and removal
  as well as module insertion and deletion, an intermediary IOC4-specific
  driver layer is needed to handle these operations cleanly.

- All IOC4 drivers are currently enabled by a single CONFIG value.  As
  not all systems need all IOC4 functions, it is desireable to enable
  these drivers independently.

- The current IOC4 core driver will trigger loading of all function-level
  drivers, as it makes direct calls to them.  This situation should be
  reversed (i.e. function-level drivers cause loading of core driver)
  in order to maintain a clear and least-surprise driver loading model.

- IOC4 hardware design necessitates some driver-level dependency on
  the PCI bus clock speed.  Current code assumes a 66MHz bus, but the
  speed should be autodetected and appropriate compensation taken.

This patch series effects the above changes by a newly and better designed
IOC4 core driver with which the function-level drivers can register and
deregister themselves upon module insertion/removal.  By tracking these
modules, device addition/removal is also handled properly.  PCI resource
management and ownership issues are centralized in this core driver, and
IOC4-wide configuration actions such as bus speed detection are also
handled in this core driver.

This patch:

The SGI IOC4 I/O controller chip implements multiple functions, though it is
not a multi-function PCI device.  Additionally, various PCI resources of the
IOC4 are shared by multiple hardware functions, and thus resource ownership by
driver is not clearly delineated.  Due to the current driver design, all core
and subordinate drivers must be loaded, or none, which is undesirable if not
all IOC4 hardware features are being used.

This patch reorganizes the IOC4 drivers so that the core driver provides a
subdriver registration service.  Through appropriate callbacks the subdrivers
can now handle device addition and removal, as well as module insertion and
deletion (though the IOC4 IDE driver requires further work before module
deletion will work).  The core driver now takes care of allocating PCI
resources and data which must be shared between subdrivers, to clearly
delineate module ownership of these items.
Signed-off-by: NBrent Casavant <bcasavan@sgi.com>
Acked-by: Pat Gefre <pfg@sgi.com
Acked-by: NJeremy Higdon <jeremy@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Arm the read timeout timer before the first read.
Signed-off-by: NPatrick Gefre <pfg@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Small mods for setting up the uart - parity, flow control
Signed-off-by: NPatrick Gefre <pfg@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Set the timeout and threshold to better values.
Signed-off-by: NPatrick Gefre <pfg@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Allow hardware flow control to be set from an ioctl.
Signed-off-by: NPatrick Gefre <pfg@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

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!