Switch to the generic get_icount implementation.

Note that the interrupt counters will no longer be reset at open which
is in accordance with which how the other drivers work.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove SMP memory barriers from icount handling and rely on the barriers
implied by wait_event, sleep and locks, while using the port lock to
guarantee atomicity.

This is a step in moving over to the generic icount implementations.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove broken get_icount and TIOCMIWAIT support.

The driver has an icount structure but it is never been updated which
makes get_icount rather pointless and causes TIOCMIWAIT to always return
-EIO.

Note that the TIOCMIWAIT implementation has always been broken and would
not work even if icount support was added as it does not wait for the
modem status to change (does not use a work queue at all).
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Switch to the generic TIOCMIWAIT implementation.

This also fixes the issue with processes waiting for
modem-status-changes not being woken up at disconnect.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Switch to the generic get_icount implementation.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove unused, private modem-status wait queue from driver. If
TIOCMIWAIT is ever implemented it must not rely on a private wait queue
which may have been released when woken up.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Switch to the generic TIOCMIWAIT implementation which does not suffer
from the races involved when using the deprecated sleep_on functions.

This also fixes the issue with processes waiting for
modem-status-changes not being woken up at disconnect.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Switch to the generic get_icount implementation.

Note that the interrupt counters will no longer be reset at open which
is in accordance with which how the other drivers work.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Switch to the generic TIOCMIWAIT implementation.

This also fixes the issue with processes waiting for
modem-status-changes not being woken up at disconnect.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Switch to the generic get_icount implementation.

Note that the interrupt counters will no longer be reset at open which
is in accordance with which how the other drivers work.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use tty-port modem-status-change wait queue on which processes are woken
up at hangup and disconnect.

Currently a process waiting on modem-status changes will not be woken on
device disconnect.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Break out TIOCMIWAIT handling from custom ioctl operation and use
tiocmiwait operation field instead.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove unused, private modem-status wait queue from driver. If
TIOCMIWAIT is ever implemented it must not rely on a private wait queue
which may have been released when woken up.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use tty-port modem-status-change wait queue on which processes are woken
up at hangup and disconnect.

Currently a process waiting on modem-status changes will not be woken on
device disconnect.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Replace custom ioctl operation with tiocmiwait.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use tty-port modem-status-change wait queue on which processes are woken
up at hangup and disconnect.

Currently a process waiting on modem-status changes will not be woken on
device disconnect as wake up was only done in dtr_rts which isn't
guaranteed to be called (e.g. if HUPCL is not set).

Also remove the redundant wake-up call from dtr_rts.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Replace custom ioctl operation with tiocmiwait.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Switch to the generic TIOCMIWAIT implementation which does not suffer
from the races involved when using the deprecated sleep_on functions.

This also fixes the issue with processes waiting for
modem-status-changes not being woken up at disconnect.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Switch to the generic get_icount implementation.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Switch to the generic get_icount implementation.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Switch to the generic TIOCMIWAIT implementation which does not suffer
from the races involved when using the deprecated sleep_on functions.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use the port-data icount for interrupt counters.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add generic get_icount implementation that subdrivers relying on the
port interrupt counters can use.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Make sure processes waiting for modem-status changes are woken up at
disconnect.

This is needed for custom subdriver TIOCMIWAIT-implementations which do
not yet handle hangup.

Even though processes on the tty-port wait queue are woken up at hangup
the wake-up call in usb-serial disconnect is still needed if a woken-up
process may go back to sleep (e.g. due to an incomplete
TIOCMIWAIT-implementation). If a disconnect occurs after a hangup, any
process waiting for changes will not be woken up a second time by the
tty-layer as the port will then have been disassociated from the tty.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add generic TIOCMIWAIT implementation which correctly handles hangup,
USB-device disconnect, does not rely on the deprecated sleep_on
functions and hence does not suffer from the races currently affecting
several usb-serial drivers.

This makes it much easier to add TIOCMIWAIT support to subdrivers as the
tricky details related to hangup and disconnect (e.g. atomicity, that
the private port data may have been freed when woken up, and waking up
processes at disconnect) have been handled once and for all.

To add support to a subdriver, simply set the tiocmiwait-port-operation
field, update the port icount fields and wake up any process sleeping on
the tty-port modem-status-change wait queue on changes.

Note that the tty-port initialised flag can be used to detect
disconnected as the port will be hung up as part of disconnect (and
cannot be reactivated due to the disconnected flag). However, as the
tty-port implementation currently wakes up processes before calling port
shutdown, the tty-hupping flag must also be checked to detect hangup for
now.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add tiocmiwait operation to struct usb_serial_driver.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Make sure to unregister the tty-device before calling subdriver
port_remove.

This way remove will reverse probe, and specifically any port data
released in port_remove will be available throughout tty unregister.

Note that the order currently does not matter as the tty-layer can make
callbacks also after the device has been unregistered. This is
handled in usb-serial core using the disconnected flag, which is
already set when usb-serial bus device remove is called.

Cc: Peter Hurley <peter@hurleysoftware.com>
Reported-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use usb_poison_urb to reliably kill all urbs on disconnect and suspend.

This way there will be no question that the urbs cannot be resubmitted
by buggy subdrivers.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The calls to usb_poison_urb and usb_unpoison_urb are expected to be
balanced. However, if an urb that has not yet been submitted is
poisoned, its reject counter will not be increased as its ep-field is
NULL. A consecutive call to unpoison will thus in fact poison the urb
as its reject counter will be decremented to a negative value,
effectively preventing the urb from being submitted.

Note that there are currently no in-kernel drivers affected by this.

Cc: Alan Stern <stern@rowland.harvard.edu>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Rename port_release so that all usb_serial_port functions have a common
prefix.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

We should not call kill_traffic (and usb_kill_urb) once disconnect
returns. Any pending urbs are killed at disconnect and new submissions
are prevented by usb_unbind_interface (and usb_disable_interface).
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Make sure the interrupt urb submitted in port_probe is killed in
port_remove.

The interrupt-urb completion handler references the port and may get
called after port_remove has returned and the port has been
unregistered (although this is currently prevented by usb-serial core as
we are using a non-private urb).
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Most USB serial drivers are, and should be, using as much of the generic
implementation as possible.

Rename the fixup_generic function to a more descriptive name.
Reword the related debug message in a more neutral tone (and remember to
add the missing newline).
Finally, move the operations initialisation to after the initial sanity
checks.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove empty generic release implementation and make the release
callback non-mandatory (like attach, probe and disconnect).
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove the now empty generic disconnect callback and make the disconnect
callback non-mandatory.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

There is no need for the generic disconnect callback to stop the read
and write urbs a second time as this has already been taken care of by
close (which is called from hangup as part of disconnect).
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The generic close operation will be used if the close field is left
uninitialised.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The disconnect callback is set to the generic implementation by
usb-serial core if NULL.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove bogus (and unnecessary) test for serial->dev being NULL in
cleanup.

The device is never cleared, and cleanup is never called after a
completed disconnect anyway.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove bogus (and unnecessary) test for serial->dev being NULL in close.

The device is never cleared, and close is never called after a completed
disconnect anyway.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>