linux-stable.git/drivers/serial/serial_core.c, branch linux-2.6.36.y

tty: untangle locking of wait_until_sent

2010-08-10T20:47:43+00:00

Some wait_until_sent versions require the big
tty mutex, others don't and some callers of
wait_until_sent already hold it while other don't.
That leads to recursive use of the BTM in these
functions, which we're trying to get rid of.

This turns all cleans up the locking there so
that the driver's wait_until_sent function
never takes the BTM itself if it is already
called with that lock held.

Signed-off-by: Arnd Bergmann 
Cc: Alan Cox 
Signed-off-by: Greg Kroah-Hartman

tty: replace BKL with a new tty_lock

2010-08-10T20:47:43+00:00

As a preparation for replacing the big kernel lock
in the TTY layer, wrap all the callers in new
macros tty_lock, tty_lock_nested and tty_unlock.

Signed-off-by: Arnd Bergmann 
Cc: Alan Cox 
Signed-off-by: Greg Kroah-Hartman

serial: fix termios settings in open

2010-08-10T20:47:43+00:00

Move termios initialization in open into uart_dtr_rts to make sure
it always gets called when necessary. Based on a suggestion from
Alan Cox.

Alan writes:
Ok this sort of makes sense. Something isn't getting initialised and both
getty and minicom will do a termios set which is sorting it out.
This is occurring because the generic block_til_ready sets
ASYNCB_NORMAL_ACTIVE so the termios updating gets skipped.

This patch should cure it and then we can think about doing it more
elegantly by getting the serial layer to use tty_port_open, kfifo and
the like and removing the tons of repeated crap in all the drivers.

Signed-off-by: Arnd Bergmann 
Reported-by: Tony Luck 
Cc: Alan Cox 
Cc: Tony Luck 
Signed-off-by: Greg Kroah-Hartman

serial: Use block_til_ready helper

2010-08-10T20:47:42+00:00

Our code now rather closely resembles the helper, so switch to it.

Signed-off-by: Alan Cox 
Cc: Arnd Bergmann 
Signed-off-by: Greg Kroah-Hartman

serial: trim locking on the helpers

2010-08-10T20:47:42+00:00

The port mutex protects port->tty, but these paths never need to walk from
port->tty. They do need the low level lock as the API expects that but they
already also take it.

Thus we can drop the extra mutex lock calls here.

Signed-off-by: Alan Cox 
Cc: Arnd Bergmann 
Signed-off-by: Greg Kroah-Hartman

serial: add port helpers

2010-08-10T20:47:42+00:00

We can make this the same as the ones that will be needed by the tty_port
helper logic that we want to move to but still call them from the existing
code base.

Signed-off-by: Alan Cox 
Cc: Arnd Bergmann 
Signed-off-by: Greg Kroah-Hartman

serial: Change the wait for carrier locking

2010-08-10T20:47:42+00:00

We want to push the lock/unlock into the helper functions so that we
can prepare to move to using the tty_port helper. The expansion initially
comes out a bit ugly but its worth the temporary expansion IMHO just so
we can produce a nice testable series of changes.

Signed-off-by: Alan Cox 
Cc: Arnd Bergmann 
Signed-off-by: Greg Kroah-Hartman

tty: serial - fix tty referencing in set_ldisc

2010-08-10T20:47:41+00:00

Pass down the ldisc number so that the drivers don't have to peek into the
tty object themselves. This lets us get rid of another case of back referencing
port to tty which we don't want (because of races versus hangup/close).

Signed-off-by: Alan Cox 
Cc: Arnd Bergmann 
Signed-off-by: Greg Kroah-Hartman

tty: serial - fix various misuses/mishandlings of port->tty

2010-08-10T20:47:41+00:00

Make it robust against hang up events. In most cases we can do this simply
by passing the right things in the first place.

Signed-off-by: Alan Cox 
Cc: Arnd Bergmann 
Signed-off-by: Greg Kroah-Hartman

serial: Fix crash if the minimum rate of the device is > 9600 baud

2010-01-20T23:03:29+00:00

In that situation if the old rate is invalid and the new rate is invalid
and the chip cannot do 9600 baud we report zero, which makes all the
drivers explode.

Instead force the rate based on min/max

Signed-off-by: Alan Cox 
Signed-off-by: Greg Kroah-Hartman