linux-toradex.git/drivers/tty/serial/serial_core.c, branch v3.9.2

serial_core.c: add put_device() after device_find_child()

2013-05-08T03:33:07+00:00

commit 5a65dcc04cda41f4122aacc37a5a348454645399 upstream.

The serial core uses device_find_child() but does not drop the reference to
the retrieved child after using it. This patch add the missing put_device().

What I have done to test this issue.

I used a machine with an AMBA PL011 serial driver. I tested the patch on
next-20120408 because the last branch [next-20120415] does not boot on this
board.

For test purpose, I added some pr_info() messages to print the refcount
after device_find_child() (lines: 1937,2009), and after put_device()
(lines: 1947, 2021).

Boot the machine *without* put_device(). Then:

echo reboot > /sys/power/disk
echo disk > /sys/power/state
[   87.058575] uart_suspend_port:1937 refcount 4
[   87.058582] uart_suspend_port:1947 refcount 4
[   87.098083] uart_resume_port:2009refcount 5
[   87.098088] uart_resume_port:2021 refcount 5

echo disk > /sys/power/state
[  103.055574] uart_suspend_port:1937 refcount 6
[  103.055580] uart_suspend_port:1947 refcount 6
[  103.095322] uart_resume_port:2009 refcount 7
[  103.095327] uart_resume_port:2021 refcount 7

echo disk > /sys/power/state
[  252.459580] uart_suspend_port:1937 refcount 8
[  252.459586] uart_suspend_port:1947 refcount 8
[  252.499611] uart_resume_port:2009 refcount 9
[  252.499616] uart_resume_port:2021 refcount 9

The refcount continuously increased.

Boot the machine *with* this patch. Then:

echo reboot > /sys/power/disk
echo disk > /sys/power/state
[  159.333559] uart_suspend_port:1937 refcount 4
[  159.333566] uart_suspend_port:1947 refcount 3
[  159.372751] uart_resume_port:2009 refcount 4
[  159.372755] uart_resume_port:2021 refcount 3

echo disk > /sys/power/state
[  185.713614] uart_suspend_port:1937 refcount 4
[  185.713621] uart_suspend_port:1947 refcount 3
[  185.752935] uart_resume_port:2009 refcount 4
[  185.752940] uart_resume_port:2021 refcount 3

echo disk > /sys/power/state
[  207.458584] uart_suspend_port:1937 refcount 4
[  207.458591] uart_suspend_port:1947 refcount 3
[  207.498598] uart_resume_port:2009 refcount 4
[  207.498605] uart_resume_port:2021 refcount 3

The refcount correctly handled.

Signed-off-by: Federico Vaga 
Signed-off-by: Greg Kroah-Hartman

tty: Remove ancient hardpps()

2013-02-13T18:17:06+00:00

hardpps() functionality is provided through the N_PPS line
discipline now. The new function signature was added in commit
025b40ab (2011-01-12). There was no previous macro or
function hardpps(), at least since before the initial commit of
v2.6.12 in 2005. It's unlikely this code has been compiled since.

Signed-off-by: Peter Hurley 
Signed-off-by: George Spelvin 
Signed-off-by: Greg Kroah-Hartman

pps: Additional cleanups in uart_handle_dcd_change

2013-02-13T18:17:06+00:00

An extension of the previous commit, there is no semantic change
here, just fewer lines of source code.

Signed-off-by: George Spelvin 
Acked-by: Rodolfo Giometti 
Signed-off-by: Greg Kroah-Hartman

pps: Move timestamp read into PPS code proper

2013-02-13T18:13:58+00:00

The PPS (Pulse-Per-Second) line discipline has developed a number of
unhealthy attachments to core tty data and functions, ultimately leading
to its breakage.

The previous patches fixed the crashing.  This one reduces coupling further
by eliminating the timestamp parameter from the dcd_change ldisc method.
This reduces header file linkage and makes the extension more generic,
and the timestamp read is delayed only slightly, from just before the
ldisc->ops->dcd_change method call to just after.

Fix attendant build breakage in
    drivers/tty/n_tty.c
    drivers/tty/tty_buffer.c
    drivers/staging/speakup/selection.c
    drivers/staging/dgrp/dgrp_*.c

Cc: William Hubbs 
Cc: Chris Brannon 
Cc: Kirk Reiser 
Cc: Samuel Thibault 
Signed-off-by: Peter Hurley 
Signed-off-by: George Spelvin 
Acked-by: Rodolfo Giometti 
Signed-off-by: Greg Kroah-Hartman

drivers/tty/serial: extern function which for release resource, need check pointer, before free it

2013-01-16T07:00:44+00:00

  for extern function uart_remove_one_port:
    need check pointer whether be NULL, before the main work.
    just like what the other extern function uart_add_one_port has done.
    uart_add_one_port and uart_remove_one_port are pair

  information:
    for the callers (such as drivers/tty/serial/jsm: jsm_tty.c, jsm_driver.c)
    they realy assume that:
      they still can call uart_remove_one_port, after uart_add_one_port failed
    we (as an extern function), have to understand it (just like kfree).

Signed-off-by: Chen Gang 
Signed-off-by: Greg Kroah-Hartman

TTY: move low_latency to tty_port

2013-01-16T06:23:16+00:00

One point is to have less places where we actually need tty pointer.
The other is that low_latency is bound to buffer processing and
buffers are now in tty_port. So it makes sense to move low_latency to
tty_port too.

Signed-off-by: Jiri Slaby 
Signed-off-by: Greg Kroah-Hartman

TTY: switch tty_insert_flip_char

2013-01-16T06:21:36+00:00

Now, we start converting tty buffer functions to actually use
tty_port. This will allow us to get rid of the need of tty in many
call sites. Only tty_port will needed and hence no more
tty_port_tty_get in those paths.

tty_insert_flip_char is the next one to proceed. This one is used all
over the code, so the patch is huge.

Signed-off-by: Jiri Slaby 
Signed-off-by: Greg Kroah-Hartman

tty: Fix comments that reference BKL, eventd, old paths

2013-01-16T05:57:44+00:00

Signed-off-by: Kevin Cernekee 
Acked-by: Alan Cox 
Signed-off-by: Greg Kroah-Hartman

tty: serial core: decouple pm states from ACPI

2013-01-16T05:52:23+00:00

The serial core is using power states lifted from ACPI for no
good reason. Remove this reference from the documentation and
alter all users to use an enum specific to the serial core
instead, and define it in .

Signed-off-by: Linus Walleij 
Acked-by: Alan Cox 
Reviewed-by: Daniel Lezcano 
Signed-off-by: Greg Kroah-Hartman

Merge branch 'omap-serial' of git://git.linaro.org/people/rmk/linux-arm

2012-12-12T15:45:16+00:00

Pull ARM OMAP serial updates from Russell King:
 "This series is a major reworking of the OMAP serial driver code fixing
  various bugs in the hardware-assisted flow control, extending up into
  serial_core for a couple of issues.  These fixes have been done as a
  set of progressive changes and transformations in the hope that no new
  bugs will be introduced by this series.

  The problems are many-fold, from the driver not being informed about
  updated settings, to the driver not knowing what the intentions of the
  upper layers are.

  The first four patches tackle the serial_core layer, allowing it to
  provide the necessary information to drivers, and the remaining
  patches allow the OMAP serial driver to take advantage of this.

  This brings hardware assisted RTS/CTS and XON/OFF flow control into a
  useful state.

  These patches have been in linux-next for most of the last cycle;
  indeed they predate the previous merge window.  They've also been
  posted to the OMAP people."

* 'omap-serial' of git://git.linaro.org/people/rmk/linux-arm: (21 commits)
  SERIAL: omap: fix hardware assisted flow control
  SERIAL: omap: simplify (2)
  SERIAL: omap: move xon/xoff setting earlier
  SERIAL: omap: always set TCR
  SERIAL: omap: simplify
  SERIAL: omap: don't read back LCR/MCR/EFR
  SERIAL: omap: serial_omap_configure_xonxoff() contents into set_termios
  SERIAL: omap: configure xon/xoff before setting modem control lines
  SERIAL: omap: remove OMAP_UART_SYSC_RESET and OMAP_UART_FIFO_CLR
  SERIAL: omap: move driver private definitions and structures to driver
  SERIAL: omap: remove 'irq_pending' bitfield
  SERIAL: omap: fix MCR TCRTLR bit handling
  SERIAL: omap: fix set_mctrl() breakage
  SERIAL: omap: no need to re-read EFR
  SERIAL: omap: remove setting of EFR SCD bit
  SERIAL: omap: allow hardware assisted IXANY mode to be disabled
  SERIAL: omap: allow hardware assisted rts/cts modes to be disabled
  SERIAL: core: add throttle/unthrottle callbacks for hardware assisted flow control
  SERIAL: core: add hardware assisted h/w flow control support
  SERIAL: core: add hardware assisted s/w flow control support
  ...

Conflicts:
	drivers/tty/serial/omap-serial.c