History log of /drivers/s390/char/con3215.c
Revision Date Author Comments (<<< Hide modified files) (Show modified files >>>)
843ec558f91b8e8fdb6efc908f2c0506407cc750 20-Mar-2012 Linus Torvalds <torvalds@linux-foundation.org> Merge tag 'tty-3.3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull TTY/serial patches from Greg KH:
"tty and serial merge for 3.4-rc1

Here's the big serial and tty merge for the 3.4-rc1 tree.

There's loads of fixes and reworks in here from Jiri for the tty
layer, and a number of patches from Alan to help try to wrestle the vt
layer into a sane model.

Other than that, lots of driver updates and fixes, and other minor
stuff, all detailed in the shortlog."

* tag 'tty-3.3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (132 commits)
serial: pxa: add clk_prepare/clk_unprepare calls
TTY: Wrong unicode value copied in con_set_unimap()
serial: PL011: clear pending interrupts
serial: bfin-uart: Don't access tty circular buffer in TX DMA interrupt after it is reset.
vt: NULL dereference in vt_do_kdsk_ioctl()
tty: serial: vt8500: fix annotations for probe/remove
serial: remove back and forth conversions in serial_out_sync
serial: use serial_port_in/out vs serial_in/out in 8250
serial: introduce generic port in/out helpers
serial: reduce number of indirections in 8250 code
serial: delete useless void casts in 8250.c
serial: make 8250's serial_in shareable to other drivers.
serial: delete last unused traces of pausing I/O in 8250
pch_uart: Add module parameter descriptions
pch_uart: Use existing default_baud in setup_console
pch_uart: Add user_uartclk parameter
pch_uart: Add Fish River Island II uart clock quirks
pch_uart: Use uartclk instead of base_baud
mpc5200b/uart: select more tolerant uart prescaler on low baudrates
tty: moxa: fix bit test in moxa_start()
...
410235fd4d20b8feaf8930a0575d23acc088aa87 05-Mar-2012 Jiri Slaby <jslaby@suse.cz> TTY: remove unneeded tty->index checks

Checking if tty->index is in bounds is not needed. The tty has the
index set in the initial open. This is done in get_tty_driver. And it
can be only in interval <0,driver->num).

So remove the tests which check exactly this interval. Some are
left untouched as they check against the current backing device count.
(Leaving apart that the check is racy in most of the cases.)

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
/drivers/s390/char/con3215.c
2f16669d322e05171c9e1cfd94f402f7399bd2a3 05-Mar-2012 Jiri Slaby <jslaby@suse.cz> TTY: remove re-assignments to tty_driver members

All num, magic and owner are set by alloc_tty_driver. No need to
re-set them on each allocation site.

pti driver sets something different to what it passes to
alloc_tty_driver. It is not a bug, since we don't use the lines
parameter in any way. Anyway this is fixed, and now we do the right
thing.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
/drivers/s390/char/con3215.c
656d9125376006cf696b0836f1c6723a892629ca 17-Feb-2012 Martin Schwidefsky <schwidefsky@de.ibm.com> [S390] 3215 deadlock with tty_wakeup

The 3215 driver calls tty_wakeup from irq context while holding the
device spinlock. If printk is called by any function on the callchain
starting from tty_wakeup the system deadlocks on the device spinlock.
Using a tasklet to call tty_wakup solves the problem.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
/drivers/s390/char/con3215.c
de400d6b78d15a73023485f050bc6b1709dc7a79 30-Oct-2011 Peter Oberparleiter <peter.oberparleiter@de.ibm.com> [S390] fix mismatch in summation of I/O IRQ statistics

Current IRQ statistics support does not show detail counts for I/O
interrupts which are processed internally only. The result is a
summation count which is way off such as this one:

CPU0 CPU1 CPU2
I/O: 1331 710 442
[...]
QAI: 15 16 16 [I/O] QDIO Adapter Interrupt
QDI: 1 0 0 [I/O] QDIO Interrupt
DAS: 706 645 381 [I/O] DASD
C15: 26 10 0 [I/O] 3215
C70: 0 0 0 [I/O] 3270
TAP: 0 0 0 [I/O] Tape
VMR: 0 0 0 [I/O] Unit Record Devices
LCS: 0 0 0 [I/O] LCS
CLW: 0 0 0 [I/O] CLAW
CTC: 0 0 0 [I/O] CTC
APB: 0 0 0 [I/O] AP Bus

Fix this by moving I/O interrupt accounting into the common I/O layer.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
/drivers/s390/char/con3215.c
3bda058b0c39fc72188116d2fd71af08dd0fe5b0 23-Mar-2011 Sebastian Ott <sebott@linux.vnet.ibm.com> [S390] ccw_driver: remove duplicate members

Remove the owner and name members of struct
ccw_driver and convert all drivers to store
this data in the embedded struct device_driver.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
/drivers/s390/char/con3215.c
12fae5858cd97181c92472c9bb5f098a7eca2ffe 05-Jan-2011 Heiko Carstens <heiko.carstens@de.ibm.com> [S390] 3215: add support for irq statistics

Add support for 3215 I/O interrupt statistics in /proc/interrupts.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
/drivers/s390/char/con3215.c
7b475d59a07cb193310afae48367bd1ea2faa411 13-Jan-2010 Heiko Carstens <heiko.carstens@de.ibm.com> [S390] con3215: remove empty ioctl function

...instead of adding a compat ioctl function which would do nothing
as well.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
/drivers/s390/char/con3215.c
42d61b9b415686d81eaa022b846737548876e51d 07-Dec-2009 Heiko Carstens <heiko.carstens@de.ibm.com> [S390] 3215/3270 console: remove wrong comment

When converting these two drivers from bootmem to slab allocations I
forgot to remove two comments which state that this wouldn't be
possible.
So remove them now since this caused confusion already.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
/drivers/s390/char/con3215.c
4f0076f77fb64889d4e5e425b63333e5764b446d 22-Jun-2009 Martin Schwidefsky <schwidefsky@de.ibm.com> [S390] driver_data access

Replace the remaining direct accesses to the driver_data pointer
with calls to the dev_get_drvdata() and dev_set_drvdata() functions.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
/drivers/s390/char/con3215.c
6d56eee2c016b0b131e444d02a66b0fef7df3ef0 22-Jun-2009 Heiko Carstens <heiko.carstens@de.ibm.com> [S390] 3215 console: convert from bootmem to slab

The slab allocator is earlier available so convert the
bootmem allocations to slab/gfp allocations.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
/drivers/s390/char/con3215.c
6fd03301d76bc439382710e449f58efbb233df1b 16-Jun-2009 Linus Torvalds <torvalds@linux-foundation.org> Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6

* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6: (64 commits)
debugfs: use specified mode to possibly mark files read/write only
debugfs: Fix terminology inconsistency of dir name to mount debugfs filesystem.
xen: remove driver_data direct access of struct device from more drivers
usb: gadget: at91_udc: remove driver_data direct access of struct device
uml: remove driver_data direct access of struct device
block/ps3: remove driver_data direct access of struct device
s390: remove driver_data direct access of struct device
parport: remove driver_data direct access of struct device
parisc: remove driver_data direct access of struct device
of_serial: remove driver_data direct access of struct device
mips: remove driver_data direct access of struct device
ipmi: remove driver_data direct access of struct device
infiniband: ehca: remove driver_data direct access of struct device
ibmvscsi: gadget: at91_udc: remove driver_data direct access of struct device
hvcs: remove driver_data direct access of struct device
xen block: remove driver_data direct access of struct device
thermal: remove driver_data direct access of struct device
scsi: remove driver_data direct access of struct device
pcmcia: remove driver_data direct access of struct device
PCIE: remove driver_data direct access of struct device
...

Manually fix up trivial conflicts due to different direct driver_data
direct access fixups in drivers/block/{ps3disk.c,ps3vram.c}
77812a27577dba6adb71b1de8ee690ced5002067 16-Jun-2009 Martin Schwidefsky <schwidefsky@de.ibm.com> [S390] pm: con3215 power management callbacks

Introduce the power management callbacks to the 3215 console. On suspend
the console buffer is flushed to the 3215 device to have an empty console
buffer. Printks done while the 3215 device is suspended are buffered in
the 64K buffer of the 3215 device. If the buffer is full new messages will
push out the oldest messages to make room for the most recent message.
On resume the buffered messages are printed. If the system panics before
the 3215 device is resumed ccw_device_force_console is used to get the
console working again.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
/drivers/s390/char/con3215.c
dff59b64af94dc588044d70f3708cb835055c5b6 04-May-2009 Greg Kroah-Hartman <gregkh@suse.de> s390: remove driver_data direct access of struct device

In the near future, the driver core is going to not allow direct access
to the driver_data pointer in struct device. Instead, the functions
dev_get_drvdata() and dev_set_drvdata() should be used. These functions
have been around since the beginning, so are backwards compatible with
all older kernel versions.

Thanks to Sebastian Ott <sebott@linux.vnet.ibm.com> for fixing a few
typos in my original version of this patch.

Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Sebastian Ott <sebott@linux.vnet.ibm.com>
Cc: linux-s390@vger.kernel.org
Cc: linux390@de.ibm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
/drivers/s390/char/con3215.c
408aec3c6c3cb5b4774f96ea7a35cd15ee91a56f 10-Oct-2008 Heiko Carstens <heiko.carstens@de.ibm.com> [S390] 3215: Remove tasklet.

The 3215 console irq handler used to schedule a tasklet. However the
console irq handler also gets called from the infamous cio_tpi()
function. Which in turn does something like

local_bh_disable()
[call console irq handler]
_local_bh_enable()

_local_bh_enable() prevents execution of softirqs, which is intended
within cio_tpi(). However there might be a new softirq pending because
irq handler scheduled a tasklet.
In order to prevent this behaviour we just get rid of the tasklet.
It's not doing much anyway.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
/drivers/s390/char/con3215.c
2332ce1a97963b7769e0c2d40492a10a124efba5 10-Oct-2008 Holger Smolinski <Holger.Smolinski@de.ibm.com> [S390] console flush on panic / reboot

The s390 console drivers use the unblank callback of the console
structure to flush the console buffer. In case of a panic or a
reboot the CPU doing the callback can block on the console i/o.
The other CPUs in the system continue to work. For panic this is
not a good idea.

Replace the unblank callback with proper panic/reboot notifier.
These get called after all but one CPU have been stopped.

Signed-off-by: Holger Smolinski <Holger.Smolinski@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
/drivers/s390/char/con3215.c
1d030370f09036e8dcb3cc40915f3f9cf92bb54c 14-Jul-2008 Heiko Carstens <heiko.carstens@de.ibm.com> [S390] Remove P390 support.

Most likely it is broken anyway because of the changes in memory
detection. Since we can't test it and there are probably better ways
that using a P390 card, remove support for it.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
/drivers/s390/char/con3215.c
26348f78e84613371eb657ca1e584153ccb7d596 14-Jul-2008 Martin Schwidefsky <schwidefsky@de.ibm.com> [S390] Cleanup 3215 printk messages.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
/drivers/s390/char/con3215.c
23d805b647db6c2063a13089497615efa9deacdd 14-Jul-2008 Peter Oberparleiter <peter.oberparleiter@de.ibm.com> [S390] cio: introduce fcx enabled scsw format

Extend the scsw data structure to the format required by fcx. Also
provide helper functions for easier access to fields which are present
in both the traditional as well as the modified format.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
/drivers/s390/char/con3215.c
9e7c9a19c1df8a7450c56c41b9c7405eca7eda07 30-Apr-2008 Alan Cox <alan@lxorguk.ukuu.org.uk> s390 tty: Prepare for put_char to return success/fail

Put the changes into the drivers first. This will still compile/work but
produce a warning if bisected so can still be debugged

Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
/drivers/s390/char/con3215.c
a2e53801971edbdaac4411760d893b8b65646987 12-Oct-2007 Cornelia Huck <cornelia.huck@de.ibm.com> [S390] 3215: Handle special console device.

The early console device is special as it already has all needed data
set and raw3215[0] allocated from con3215_init(). Therefore, it needs
special treatment in the probe function so it can be matched with the
3215 driver which is already owning it.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
/drivers/s390/char/con3215.c
60691d3c2c0fe9ecc264741ff41f283fef579b8a 27-Apr-2007 Heiko Carstens <heiko.carstens@de.ibm.com> [S390] Get rid of console setup functions.

We get this:

Section mismatch: reference to .init.text:con3270_consetup from .data
between 'con3270' (at offset 0x45c8) and 'con3270_fn'
Section mismatch: reference to .init.text:con3215_consetup from .data
between 'con3215' (at offset 0x4678) and
'raw3215_ccw_driver'

Since there is no difference between a non present console setup
function and one that returns only 0 remove them.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
/drivers/s390/char/con3215.c
2b67fc46061b2171fb8fbb55d1ac717abd533569 05-Feb-2007 Heiko Carstens <heiko.carstens@de.ibm.com> [S390] Get rid of a lot of sparse warnings.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
/drivers/s390/char/con3215.c
5cbded585d129d0226cb48ac4202b253c781be26 13-Dec-2006 Robert P. J. Day <rpjday@mindspring.com> [PATCH] getting rid of all casts of k[cmz]alloc() calls

Run this:

#!/bin/sh
for f in $(grep -Erl "\([^\)]*\) *k[cmz]alloc" *) ; do
echo "De-casting $f..."
perl -pi -e "s/ ?= ?\([^\)]*\) *(k[cmz]alloc) *\(/ = \1\(/" $f
done

And then go through and reinstate those cases where code is casting pointers
to non-pointers.

And then drop a few hunks which conflicted with outstanding work.

Cc: Russell King <rmk@arm.linux.org.uk>, Ian Molton <spyro@f2s.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Greg KH <greg@kroah.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Paul Fulghum <paulkf@microgate.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Karsten Keil <kkeil@suse.de>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Ian Kent <raven@themaw.net>
Cc: Steven French <sfrench@us.ibm.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Neil Brown <neilb@cse.unsw.edu.au>
Cc: Jaroslav Kysela <perex@suse.cz>
Cc: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
/drivers/s390/char/con3215.c
520a4e3728c214db6e91ade7b70443c2b9382de0 04-Dec-2006 Martin Schwidefsky <schwidefsky@de.ibm.com> [S390] 3215 device locking.

Remove lock pointer from 3215 device structure. Use get_ccwdev_lock
for each use of the lock in the ccw-device structure.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
/drivers/s390/char/con3215.c
b68e31d0ebbcc909d1941f9f230c9d062a3a13d3 02-Oct-2006 Jeff Dike <jdike@addtoit.com> [PATCH] const struct tty_operations

As part of an SMP cleanliness pass over UML, I consted a bunch of
structures in order to not have to document their locking. One of these
structures was a struct tty_operations. In order to const it in UML
without introducing compiler complaints, the declaration of
tty_set_operations needs to be changed, and then all of its callers need to
be fixed.

This patch declares all struct tty_operations in the tree as const. In all
cases, they are static and used only as input to tty_set_operations. As an
extra check, I ran an i386 allyesconfig build which produced no extra
warnings.

53 drivers are affected. I checked the history of a bunch of them, and in
most cases, there have been only a handful of maintenance changes in the
last six months. serial_core.c was the busiest one that I looked at.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
/drivers/s390/char/con3215.c
d2c993d845781d160a7ef759a3e65c6892c4a270 12-Jul-2006 Heiko Carstens <heiko.carstens@de.ibm.com> [S390] Fix sparse warnings.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
/drivers/s390/char/con3215.c
6ab3d5624e172c553004ecc862bfeac16d9d68b7 30-Jun-2006 Jörn Engel <joern@wohnheim.fh-wedel.de> Remove obsolete #include <linux/config.h>

Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
/drivers/s390/char/con3215.c
600b5d163d7434332539cac7be00f649cbbfedcc 01-Feb-2006 Peter Oberparleiter <peter.oberparleiter@de.ibm.com> [PATCH] s390: ccw_device_probe_console return value

The return code of ccw_device_probe_console() is not properly handled. It
should only return a valid ccw device pointer or a error value converted by
ERR_PTR. Fix the console driver code to check with IS_ERR instead against
NULL.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
/drivers/s390/char/con3215.c
33f0f88f1c51ae5c2d593d26960c760ea154c2e2 10-Jan-2006 Alan Cox <alan@lxorguk.ukuu.org.uk> [PATCH] TTY layer buffering revamp

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: Alan Cox <alan@redhat.com>
Cc: Paul Fulghum <paulkf@microgate.com>
Signed-off-by: Hirokazu Takata <takata@linux-m32r.org>
Signed-off-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: John Hawkes <hawkes@sgi.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
/drivers/s390/char/con3215.c
17fd682e544556a2a829e94383239c029bb21c5e 07-Nov-2005 Jesper Juhl <jesper.juhl@gmail.com> [PATCH] kfree cleanup: drivers/s390

This is the drivers/s390/ part of the big kfree cleanup patch.

Remove pointless checks for NULL prior to calling kfree() in drivers/s390/.

Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Acked-by: Cornelia Huck <cohuck@de.ibm.com>
Acked-by: Stefan Bader <Stefan.Bader@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
/drivers/s390/char/con3215.c
6b979de395c7e1b7e59f74a870e1d1911853eccb 25-Jun-2005 Christian Borntraeger <cborntra@de.ibm.com> [PATCH] s390: add vmcp interface

Add interface to issue VM control program commands.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
/drivers/s390/char/con3215.c
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 17-Apr-2005 Linus Torvalds <torvalds@ppc970.osdl.org> Linux-2.6.12-rc2

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!
/drivers/s390/char/con3215.c