The function ccw_device_unregister has to ensure to remove
all references obtained by device_add and device_initialize.
Unfortunately it gets called for devices which are
1) uninitialized, 2) initialized but unregistered, and
3) registered devices. To distinguish 1) and 2) this patch
introduces a new flag "initialized", which is 1 as long as we
hold the initial device reference.
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

We used to maintain a "registered" flag in our ccw_device_private
structure. This patch removes the "registered" flag and converts
all users of it to device_is_registered which has the exact same
meaning.

Note: The usage the atomic operation test_and_clear_bit is replaced
by the non-atomic if (device_is_registered()) device_del(). This
will not do harm, since we serialize calls to ccw_device_unregister
with a single-threaded workqueue.
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Set-pgid operations fail for some device types under z/VM for which
the hypervisor has already set the pgid. Also reserved devices or
changed pgids are not correctly recognized. Fix these problems by
using a combination of sense-pgid and set-pgid and by also accepting
pre-defined pgid settings.
Signed-off-by: NPeter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Split setting (driver wants feature enabled) and status (feature
setup was successful) for PGID related ccw device features so that
setup errors can be detected. Previously, incorrectly handled setup
errors could in rare cases lead to erratic I/O behavior and
permanently unusuable devices.
Signed-off-by: NPeter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

After changing all internal I/O functions to use the newly introduced
ccw request infrastructure, retries are handled automatically after a
clear operation. Therefore remove the internal retry flag and
associated code.
Signed-off-by: NPeter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Use the newly introduced ccw request infrastructure to implement
pgid related operations: sense pgid, set pgid and disband pg.
Signed-off-by: NPeter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Reduce code duplication by introducing a central infrastructure to
perform an internal I/O operation on a CCW device.
Signed-off-by: NPeter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Introduce a central mechanism for performing delayed ccw device work
to ensure that different types of work do not overwrite each other.
Prioritization ensures that the most important work is always
performed while less important tasks are either obsoleted or repeated
later.
Signed-off-by: NPeter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Fix incorrect in- and output constraints, remove volatile declaration
of inline assembly parameters and reformat constraint declarations to
be more consistent.
Signed-off-by: NPeter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

This patch adds a driver for subchannels of type chsc.

A device /dev/chsc is created which may be used to issue ioctls to:
- obtain information about the machine's I/O configuration
- dynamically change the machine's I/O configuration via
  asynchronous chsc commands
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>

Provide functions for assembling and starting fcx enabled I/O request
blocks.
Signed-off-by: NPeter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>

Also define helpers sch_{g,s}et_cdev() to make the intention more
clear.
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Introduce a private pointer in struct subchannel to store
per-subchannel type data (cannot use dev->priv since this
is already used for something else).

Create a new header io_sch.h for I/O subchannel specific structures
and instructions.
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>