Commit Graph

147918 Commits

Author SHA1 Message Date
Daniel Glöckner
26bbb3ff1f imx: serial: fix one bit field type
"have_rtscts" is assigned 1, while it is declared
int:1, two's complement, which can hold 0 and -1
only. The code works, as the upper bits are cut
off, and tests are done against 0 only.

Nonetheless, correctly declaring the bit field
as unsigned int:1 renders the code more robust.

Signed-off-by: Daniel Glöckner <dg@emlix.com>
Signed-off-by: Oskar Schirmer <os@emlix.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:08 -07:00
Oskar Schirmer
d3810cd4d7 imx: serial: fix whitespaces (no changes in functionality)
Signed-off-by: Oskar Schirmer <os@emlix.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:07 -07:00
Jiri Slaby
3e3b5c0877 tty: use prepare/finish_wait
Use prepare_to_wait and finish_wait instead of add_wait_queue and
remove_wait_queue.

This avoids us setting a task state.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:07 -07:00
Jiri Slaby
5fc5b42a3b tty: remove sleep_on
Use wait_event instead of sleep_on in tty_block_til_ready.

Wait for ASYNC_CLOSING flag being 0.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:07 -07:00
Elina Pasheva
4db2299da2 sierra: driver interface blacklisting
Interface blacklisting is necessary for non-serial interfaces that are handled
by a different driver. The interface blacklisting is implemented in sierra
driver per device. Each device in need of a blacklist has a static information
array kept in the driver. This array contains the interface numbers that are
blacklisted. The pointer for each blacklist array and the length
of that blacklist are 'bundled' in data structure sierra_iface_info. A pointer
to this information is set in id_table when the device is added to the id_table.

The following is summary of changes we have made to sierra.c driver in
this patch dealing with interface blacklisting support:
- Added data structure sierra_iface_info and function is_blacklisted()
to support blacklisting
- Modified sierra_probe() to handle blacklisted interfaces accordingly
- Improved comments in id_table
- Added new device in id_table with blacklist interface support

Signed-off-by: Elina Pasheva <epasheva@sierrawireless.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:07 -07:00
Elina Pasheva
b9a44bc19f sierra: driver urb handling improvements
[Folded from eight patches into one as the original set according to the
 author "All of the patches need to be applied to obtain a working product"
 so keeping them split seems unhelpful

 Merge fixes done versus other conflicting changes and moved the
 spin_lock_init from open to setup time -- Alan]

Summary of the changes and code re-organization in this patch:

- The memory for urbs is allocated and urbs are submitted only for the active
  interfaces (instead of pre-allocating these for all interfaces). This will
  save memory especially in the case of using composite devices.
- The code has been re-organized and functionality has been extracted from
  sierra_startup(), sierra_shutdown(), sierra_open(), sierra_close() and added
  in helper functions sierra_release_urb(), sierra_stop_rx_urbs(),
  sierra_submit_rx_urbs() and sierra_setup_urb()

- Added function sierra_release_urb() to free an urb and its transfer
buffer.
- Removed unecessary include file reference and comment.
- Added function sierra_stop_rx_urbs() that takes care of the release of
receive and interrupt urbs. This function is to be called by sierra_close()
whenever an interface is de-activated.
- Added new function sierra_submit_rx_urbs() that handles the submission of
receive urbs and interrupt urbs (if any) during the interface activation.
This function is to be called by sierra_open(). Added a second parameter to
pass the memory allocation (as suggested by Oliver Neukum) so that this
function can be used in post_reset() and resume().
- Added new function sierra_setup_urb() that contains the functionality to
allocate an urb, fill bulk urb using the supplied memory allocation flag
and release urb upon error. Added parameter so that the caller pass the
memory allocation flag for flexibility.
- Moved sierra_close() before sierra_open() to resolve dependencies
introduced by the code reorganization.
- Modified sierra_close() to call sierra_stop_rx_urbs() and
sierra_release_urb() functions added in previous patch.
- Modified sierra_open() to call sierra_setup_urb() and sierra_submit_rx_urbs()
functions; note urbs are allocated and submitted for each activated interface.
- Modified sierra_startup() so that allocation of urbs happens whenever an
interface is activated (urb allocation is moved to sierra_open()).
- Modified sierra_shutdown() so that urbs are freed whenever an interface is
de-activated (urb freeing moved to sierra_close() as shown in previous patch
from the series)
- Removed unecessary data structure from sierra_port_private_data
- Suppress an entry in logs by not re-submitting an urb when usb_submit_urb()
returns -EPERM, as this shows that usb_kill_urb() is running (as suggested by
Oliver Neukum)

Signed-off-by: Elina Pasheva <epasheva@sierrawireless.com>
Signed-off-by: Alan Cox <alan.cox@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:07 -07:00
Alan Cox
00b040deca tty: resolve some sierra breakage
The various merges into the sierra driver inadvertently undid
commit 212b8f0c3f by Elina Pasheva
<epasheva@sierrawireless.com>. Put it back so the OBEX port works again.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:07 -07:00
Alan Cox
7d55deaf50 timbuart: Fix the termios logic
The driver only handles speeds but it fails to return the current values
for the hardware features it does not support.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:06 -07:00
Richard Röjfors
34aec59184 serial: Added Timberdale UART driver
Driver for the UART found in the Timberdale FPGA

Signed-off-by: Richard Röjfors <richard.rojfors.ext@mocean-labs.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:06 -07:00
Alan Cox
e960bf73dd tty: Add URL for ttydev queue
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:06 -07:00
Alan Cox
93d5581e20 devpts: unregister the file system on error
Closes-bug: http://bugzilla.kernel.org/show_bug.cgi?id=13429

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:06 -07:00
Alan Cox
26a2e20f4a tty: Untangle termios and mm mutex dependencies
Although this doesn't cause any problems it could potentially do so for
future mmap using devices. No real work is needed to sort it out so untangle
it before it causes problems

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:06 -07:00
Mike Frysinger
0b91421857 tty: bfin_jtag_comm: emulate a TTY over the Blackfin EMUDAT/JTAG interface
The Blackfin JTAG interface has a 4 byte generic data field (EMUDAT).  With
a little creative thinking, we can turn this into a TTY device.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:06 -07:00
Alan Cox
7e9cd3a617 ftdi_sio: don't override modem bits
The new open/close logic handles DTR and friends, so don't do it in our own
open routine as well.

Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:06 -07:00
Alan Cox
7f8d09eae2 tty: fix bluetooth scribbling on low latency flags
Bluetooth shouldn't be doing this as most drivers don't support the flag,
furthermore it shouldn't be needed with newer buffering. This becomes rather
more visible as the locking fixes make the abuse of low_latency visible as
spew on the users console/dmesg.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:05 -07:00
Alan Cox
557aaa7ffa ft232: support the ASYNC_LOW_LATENCY flag
This allows users to use the standard setserial command with this FT232
feature as well as obscure chip specific interfaces we have now. We keep
track of and respect the sysfs value for non-low-latency cases. In theory we
could do smart stuff with VTIME and the like but this seems of questionable
worth.

Closes-bug: http://bugzilla.kernel.org/show_bug.cgi?id=9120
Signed-off-by: Alan Cox <alan@linux.intel.com)
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:05 -07:00
Craig Shelley
4cc27bd6d7 USB: CP210X Replace CP2101 with CP210x
This patch replaces the string "CP2101" with "CP210x" within cp210x.c
This is to reduce confusion about the fact that the driver is actually
compatible with CP2101, CP2102 and CP2103 devices.

Signed-off-by: Craig Shelley <craig@microtron.org.uk>

(Fixed some collisions merging)

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:05 -07:00
Craig Shelley
93ef1f1fbc USB: CP210X Use official request code definitions
The CP210X driver was developed without official device specifications.
This has lead to an incorrect assumption that all GET request codes are
equal to the corresponding SET request code +1.
This patch removes this incorrect assumption, and uses request code
definitions based on the updated GPL driver from SiLabs.
This modification is needed before extended functionality such as GPIO
on CP2103 can be supported.

Signed-off-by: Craig Shelley <craig@microtron.org.uk>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:05 -07:00
Craig Shelley
b7c7cbc898 USB: CP210X Add device IDs
Signed-off-by: Craig Shelley <craig@microtron.org.uk>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:05 -07:00
Sonic Zhang
2860b79111 Blackfin Serial Driver: disable dma rx interrupt only rather than all irqs
The UART RX handling code isn't exactly speeding, so don't go disabling
all interrupts when processing the buffer.  Just disable the relevant DMA
interrupt.  This greatly improves latency of the system when utilizing the
UART.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:05 -07:00
Sonic Zhang
84507794a9 Blackfin Serial Driver: handle anomaly 05000231
05000231 - UART STB Bit Incorrectly Affects Receiver Setting
For processors affected by this, we cannot safely allow CSTOPB to be set
as the UART will then be unable to properly clock in bytes.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:04 -07:00
Sonic Zhang
0efa4f2c94 Blackfin Serial Driver: annotate anomalies 05000215 and 05000099
Add some comments for how these anomalies are addressed:

05000215 - UART TX Interrupt Masked Erroneously
We always clear ETBEI within last UART TX interrupt to end
a string.  It is always set when starting a new tx transfer.

05000099 - UART Line Status Register (UART_LSR) Bits Are Not Updated at
the Same Time
This anomaly affects driver only in POLL code where multi bits of
UART_LSR are checked. It doesn't affect current bfin_5xx.c driver.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:04 -07:00
Sonic Zhang
35ff693579 Blackfin Serial Driver: handle irregular DMA register status in auto start mode
This bug is caused by irregular behavior of DMA register CURR_X_COUNT
and CURR_Y_COUNT when an auto restart uart rx DMA run to last byte in
DMA buffer, trigger the interrupt and stay at this possiton. The status
of current x and y is 0:7 instead of 512:8 or 0:8. The driver doesn't
take care of this case when calculating the position.

URL: http://blackfin.uclinux.org/gf/tracker/5063
Reported-by: Tomasz Motylewski <t.motylewski@bfad.de>

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:04 -07:00
Graf Yang
f9d36da9cd Blackfin Serial Driver: fix missing new lines when under load
Add a SSYNC() into bfin_serial_dma_tx_chars() to ensure DMA registers are
written with new data otherwise we might miss a byte or two when the
system is under load.  PIO mode is OK though.

Signed-off-by: Graf Yang <graf.yang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:04 -07:00
Robin Getz
7de7c55bf5 Blackfin Serial Driver: fix baudrate for early_printk
Since we already setup the early console UART in
arch/blackfin/kernel/early_printk.c, and common functions which are
enabled from the .setup will override the proper settings later, don't
fill in these structures.  Otherwise we get mangled baudrate settings when
using early_printk.

Signed-off-by: Robin Getz <rgetz@blackfin.uclinux.org>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:04 -07:00
Sonic Zhang
8516c568f2 Blackfin Serial Driver: fix error while transferring large files
Ignore receiving data if new position is in the same line of current
buffer tail and is small.  This should decrease overruns.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:04 -07:00
Mike Frysinger
4328e3e5ef Blackfin SPORT UART: rewrite inline assembly
Hopefuly the new version is easier to read, but in the process it declares
proper clobber lists and better constraints so that GCC can do a better
job at allocating free registers.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:04 -07:00
Michael Hennerich
a19e8b2059 Blackfin SPORT UART: fix data misses while using transmit frame sync
SPORT transmit frame sync (TFS) isn't used as an electrical signal during
normal SPORT UART emulation.  However, it is useful in EIA RS-485
emulation as RS-485 Transceiver Driver Enable DE strobe.

This patch configures:
TFS to be active high in order to drive an DE strobe of
an eventually connected RS-485 Transceiver.

Late frame sync mode (LATFS) gating the entire TX shift cycle.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:03 -07:00
Mike Frysinger
b5c6794fe4 Blackfin SPORT UART: fix typo in sport_set_termios prototype
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:03 -07:00
Florian Fainelli
08e0992f60 serial: add support for the TI AR7 internal UART
This patch adds support for the TI AR7 internal UART.

Signed-off-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:03 -07:00
Breno Leitao
257a6e8cc7 icom: fix compile errors when defining ICOM_TRACE
As it is, defining ICOM_TRACE produces some compile errors, as
"parameter name omitted" and "redefinition of ‘trace’"

This patch removes the wrong trace definition.

Signed-off-by: Breno Leitao <leitao@linux.vnet.ibm.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:03 -07:00
Alan Cox
181bf1e815 parport_pc: clean up the modified while loops using for
And tidy up a few bits coding style detectors missed

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:03 -07:00
Alan Cox
3aeda9bc95 parport_pc: Coding style
Michael's patch fixed some of the coding style so the style is now
inconsistent. Sort the rest out

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:03 -07:00
Michael Buesch
73e0d48b8c parport_pc: Fix subscription bugs
This patch fixes array subscription bugs in the parport_pc driver.

drivers/parport/parport_pc.c: In function ‘parport_irq_probe’:
drivers/parport/parport_pc.c:1589: warning: array subscript is above array bounds
drivers/parport/parport_pc.c: In function ‘parport_pc_probe_port’:
drivers/parport/parport_pc.c:1579: warning: array subscript is above array bounds

The patch also fixes a few other array bugs, which the compiler was
unable to find. Coding style violations are also fixed.

Signed-off-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:03 -07:00
Alan Cox
0b4068a128 tty: simplify buffer allocator cleanups
Having cleaned up the allocators we might as well remove the inline helpers
for some of it

Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:02 -07:00
Alan Cox
c481c707fe tty: remove buffer special casing
Long long ago a 4K kmalloc allocated two pages so the tty layer used the
page allocator, except on some machines where the page size was huge. This was
removed from the core tty layer with the tty buffer re-implementation but not
from tty_audit or the n_tty ldisc.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:02 -07:00
Breno Leitao
aba6593bf7 icom: fixing a if clause spaghetti
adapter->version can only be ADAPTER_V2 or ADAPTER_V1. So,
that OR operand in the "if" clause is non-sense and can be removed.

Signed-off-by: Breno Leitao <leitao@linux.vnet.ibm.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:02 -07:00
Alexander Y. Fomichev
13858d3690 jsm: correctly support multiple 4/8-port boards
If there are more then one 4/8-port board jsm_uart_port_init
allocate a line numbers of the second and further boards
from range of previous one.

This patch fixed the problem.

Signed-off-by: Alexander Y. Fomichev <git.user@gmail.com>

[printks fixed to add jsm: ]

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:02 -07:00
Olivier Bornet
9bb41699ad tty: iuu_phoenix: update version number.
Signed-off-by: Olivier Bornet <Olivier.Bornet@puck.ch>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:02 -07:00
Olivier Bornet
96dab77ebf tty: iuu_phoenix: set termios.
set_termios can now be used for setting the parity and the stopbits. This is
needed to use with cards which use a different parity then the parity used at
start (even).

If the iuu_uart_baud function return an error, we will return the old_termios
instead of the new one.

Signed-off-by: Olivier Bornet <Olivier.Bornet@puck.ch>

This was then revamped to use the various helpers, not copy non-hardware
bits any to add mark/space parity and csize reporting

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:02 -07:00
Olivier Bornet
cc3447d179 tty: iuu_phoenix: Fix stopbit when uart goes on.
Signed-off-by: Olivier Bornet <Olivier.Bornet@puck.ch>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:02 -07:00
Olivier Bornet
5fcf62b0f1 tty: iuu_phoenix: fix locking.
Bring in the relevant bits of the 0.9 vendor driver.

Signed-off-by: Olivier Bornet <Olivier.Bornet@puck.ch>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:01 -07:00
Alan Cox
852e99d22f tty: bring ldisc into CodingStyle
Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:01 -07:00
Alan Cox
f2c4c65c83 tty: Move ldisc_flush
We have a tty_ldisc file now so put tty_ldisc_flush in the right place

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:01 -07:00
Alan Cox
c65c9bc3ef tty: rewrite the ldisc locking
There are several pretty much unfixable races in the old ldisc code, especially
with respect to pty behaviour and also to hangup. It's easier to rewrite the
code than simply try and patch it up.

This patch
- splits the ldisc from the tty (so we will be able to refcount it more cleanly
  later)
- introduces a mutex lock for ldisc changing on an active device
- fixes the complete mess that hangup caused
- implements hopefully correct setldisc/close/hangup locking

There are still some problems around pty pairs that have always been there but
at least it is now possible to understand the code and fix further problems.

This fixes the following known bugs
- hang up can leak ldisc references
- hang up may not call open/close on ldisc in a matched way
- pty/tty pairs can deadlock during an ldisc change
- reading the ldisc proc files can cause every ldisc to be loaded

and probably a few other of the mysterious ldisc race reports.

I'm sure it also adds the odd new one.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:01 -07:00
Alan Cox
e8b70e7d3e tty: Extract various bits of ldisc code
Before trying to tackle the ldisc bugs the code needs to be a good deal
more readable, so do the simple extractions of routines first.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:01 -07:00
Alan Cox
5f0878acba tty: Fix oops when scanning the polling list for kgdb
Costantino Leandro found a bug in tty_find_polling_driver and provided a
patch that fixed the crash but not the underlying bug. This fixes the
underlying bug where the list walk corrupts the values it is using on a
match but then reuses them if the open fails.

Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:01 -07:00
Alan Cox
620df3c0a5 pty: Fix a comment
We fixed the globals, so now fix the comment

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:00 -07:00
Alan Cox
4b6ae89ef4 serial: update maintainers file
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:50:59 -07:00
Alan Cox
38db89799b tty: throttling race fix
The tty throttling code can race due to the lock drops. It takes very high
loads but this has been observed and verified by Rob Duncan.

The basic problem is that on an SMP box we can go

	CPU #1				CPU #2
	need to throttle ?
	suppose we should		buffer space cleared
					are we throttled
					yes ? - unthrottle
	call throttle method

This changeet take the termios lock to protect against this. The termios
lock isn't the initial obvious candidate but many implementations of throttle
methods already need to poke around their own termios structures (and nobody
really locks them against a racing change of flow control).

This does mean that anyone who is setting tty->low_latency = 1 and then
calling tty_flip_buffer_push from their unthrottle method is going to end up
collapsing in a pile of locks. However we've removed all the known bogus
users of low_latency = 1 and such use isn't safe anyway for other reasons so
catching it would be an improvement.

Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:50:59 -07:00