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  1. 10 10月, 2009 1 次提交
  3. 23 9月, 2009 1 次提交
    • D
      USB: use kfifo to buffer usb-generic serial writes · 8e8dce06
      由 David VomLehn 提交于 
      When do_output_char() attempts to write a carriage return/line feed sequence,
it first checks to see how much buffer room is available. If there are at least
two characters free, it will write the carriage return/line feed with two calls
to tty_put_char(). It calls the tty_operation functions write() for devices that
don't support the tty_operations function put_char(). If the USB generic serial
device's write URB is not in use, it will return the buffer size when asked how
much room is available. The write() of the carriage return will cause it to mark
the write URB busy, so the subsequent write() of the line feed will be ignored.

This patch uses the kfifo infrastructure to implement a write FIFO that
accurately returns the amount of space available in the buffer.
Signed-off-by: NDavid VomLehn <dvomlehn@cisco.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
      8e8dce06
  5. 20 9月, 2009 1 次提交
  7. 11 7月, 2009 2 次提交
  9. 16 6月, 2009 4 次提交
    • A
      USB: usb-serial: replace shutdown with disconnect, release · f9c99bb8
      由 Alan Stern 提交于 
      This patch (as1254) splits up the shutdown method of usb_serial_driver
into a disconnect and a release method.

The problem is that the usb-serial core was calling shutdown during
disconnect handling, but drivers didn't expect it to be called until
after all the open file references had been closed.  The result was an
oops when the close method tried to use memory that had been
deallocated by shutdown.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
      f9c99bb8
    • J
      USB: usb_serial: only allow sysrq on a console port · 568d422e
      由 Jason Wessel 提交于 
      The only time a sysrq should get processed is if the attached device
is a console.  This is intended to protect sysrq execution on a host
connected with a terminal program.

Here is the problem scenario:

host A <-- rs232 link --> host B

Host A is using mincom and a usb pl2303 device to connect to host b
which is a linux system with a usb pl2303 device acting as the serial
console.  When host B is rebooted the pl2303 emits random junk
characters on reset.  These character sequences contain serial break
signals most of the time and when translated to a sysrq have caused
host A to get random processes killed, reboots or power down.

It is true that in this setup with this patch host B might still have
the same problem as host A if you reboot host A.  In most cases host A
is a development host which seldom gets rebooted, and you could turn
off sysrq temporarily on host B if you need to reboot host A.
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
      568d422e
    • J
      USB: serial: usb_debug,usb_generic_serial: implement sysrq and serial break · 98fcb5f7
      由 Jason Wessel 提交于 
      The usb_debug driver was modified to implement serial break handling
by using a "magic" data packet comprised of the sequence:

       0x00 0xff 0x01 0xfe   0x00 0xfe 0x01 0xff

When the tty layer requests a serial break the usb_debug driver sends
the magic packet.  On the receiving side the magic packet is thrown
away or a sysrq is activated depending on what kernel .config options
have been set.

The generic serial driver was modified as well as the usb serial
headers to generically implement sysrq processing in the same way the
non usb uart based drivers implement the sysrq handling.  This will
allow other usb serial devices to implement sysrq handling as desired.

The new usb serial functions are named similarly and implemented
similarly to the uart functions as follows:

usb_serial_handle_break <-> uart_handle_break
usb_serial_handle_sysrq_char <-> uart_handle_sysrq_char
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
      98fcb5f7
    • J
      USB: usb_debug, usb_generic_serial: implement multi urb write · 715b1dc0
      由 Jason Wessel 提交于 
      The usb_debug driver, when used as the console, will always fail to
insert the carriage return and new line sequence as well as randomly
drop console output.  This is a result of only having the single
write_urb and that the tty layer will have a lock that prevents the
processing of the back to back urb requests.

The solution is to allow more than one urb to be outstanding and have
a slightly deeper transmit queue.  The idea and some code is borrowed
from the ftdi_sio usb driver.

The generic usb serial driver was modified so as to allow the classic
method of 1 write urb, or a multi write urb scheme with N allowed
outstanding urbs where N is controlled by max_in_flight_urbs.  When
max_in_flight_urbs in a "struct usb_serial_driver" is non zero the
multi write urb scheme will be used.

The size of 4000 was selected for the usb_debug driver so that the
driver lowers possibility of losing the queued console messages during
the kernel startup.
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
      715b1dc0
  11. 11 6月, 2009 1 次提交
  13. 24 4月, 2009 1 次提交
  15. 25 3月, 2009 2 次提交
  17. 14 10月, 2008 1 次提交
    • A
      tty: usb-serial krefs · 4a90f09b
      由 Alan Cox 提交于 
      Use kref in the USB serial drivers so that we don't free tty structures
from under the URB receive handlers as has historically been the case if
you were unlucky. This also gives us a framework for general tty drivers to
use tty_port objects and refcount.

Contains two err->dev_err changes merged together to fix clashes in the
-next tree.
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      4a90f09b
  19. 23 7月, 2008 2 次提交
  21. 25 4月, 2008 4 次提交
  23. 11 3月, 2008 1 次提交
  25. 02 2月, 2008 1 次提交
    • S
      USB: Prepare serial core for autosuspend. · f0fbd5b9
      由 Sarah Sharp 提交于 
      Claim the interface for a USB to serial converter when the tty is open,
and release the interface when the tty is closed.

If a driver doesn't provide a resume function, use the generic resume
instead.

Make sure the generic resume function does not submit the URBs if we're
coming back from autosuspend.  On autoresume, we know that the open
function will be called next, which will attempt to submit the URBs.  If
we submit them in the resume function, the open will fail.

This works for:
 - autosuspend
 - suspending with the tty open or closed
 - hibernate with the tty closed

A hibernate (or a suspend that causes the USB subsystem to lose power)
has issues.  If you have the tty open when you hibernate, a new tty will
be created when the device re-enumerates during resume.
Signed-off-by: NSarah Sharp <sarah.a.sharp@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
      f0fbd5b9
  27. 29 11月, 2007 1 次提交
  29. 26 10月, 2007 1 次提交
  31. 13 7月, 2007 3 次提交
  33. 27 3月, 2007 1 次提交
  35. 17 2月, 2007 1 次提交
    • J
      USB: add flow control to usb-serial generic driver. · 253ca923
      由 Joris van Rantwijk 提交于 
      I added two fields to struct usb_serial_port to keep track of the
throttle state. Other usb-serial drivers typically use private data for
such things, but the generic driver can not really do that because some
of its code is also used by other drivers (which may have their own
private data needs).

As it is, I am not sure that this patch is useful in all scenarios.
It is certainly helpful for low-bandwidth devices that can hold their
data in response to throttling. But for devices that pump data in
real-time as fast as possible (webcam, A/D converter, etc), throttling
may actually cause more data loss.

From: Joris van Rantwijk <jorispubl@xs4all.nl>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
      253ca923
  37. 08 2月, 2007 1 次提交
  39. 05 10月, 2006 1 次提交
    • D
      IRQ: Maintain regs pointer globally rather than passing to IRQ handlers · 7d12e780
      由 David Howells 提交于 
      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)
      7d12e780
  41. 29 9月, 2006 1 次提交
  43. 13 7月, 2006 2 次提交
  45. 01 7月, 2006 1 次提交
  47. 22 6月, 2006 1 次提交
  49. 13 5月, 2006 1 次提交
  51. 11 1月, 2006 1 次提交
    • A
      [PATCH] TTY layer buffering revamp · 33f0f88f
      由 Alan Cox 提交于 
      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>
      33f0f88f
  53. 05 1月, 2006 2 次提交