[S390] cio: Documentation update.

cds.txt

	- s390 common device support (common I/O layer).

CommonIO

	- common I/O layer command line parameters and /proc entries

	- common I/O layer command line parameters, procfs and debugfs	entries

config3270.sh

	- example configuration for 3270 devices.

DASD

S/390 common I/O-Layer - command line parameters and /proc entries

==================================================================

S/390 common I/O-Layer - command line parameters, procfs and debugfs entries

============================================================================

Command line parameters

-----------------------

* cio_msg = yes | no

  Determines whether information on found devices and sensed device 

  characteristics should be shown during startup, i. e. messages of the types 

  "Detected device 0.0.4711 on subchannel 0.0.0042" and "SenseID: Device

  0.0.4711 reports: ...".

  characteristics should be shown during startup or when new devices are

  found, i. e. messages of the types "Detected device 0.0.4711 on subchannel

  0.0.0042" and "SenseID: Device 0.0.4711 reports: ...".

  Default is off.

  An ignored device can be un-ignored later; see the "/proc entries"-section for

  details.

  The devices must be given either as bus ids (0.0.abcd) or as hexadecimal

  device numbers (0xabcd or abcd, for 2.4 backward compatibility).

  The devices must be given either as bus ids (0.x.abcd) or as hexadecimal

  device numbers (0xabcd or abcd, for 2.4 backward compatibility). If you

  give a device number 0xabcd, it will be interpreted as 0.0.abcd.

  You can use the 'all' keyword to ignore all devices.

  The '!' operator will cause the I/O-layer to _not_ ignore a device.

  The command line is parsed from left to right.

  will add 0.0.a000-0.0.accc and 0.0.af00-0.0.afff to the list of ignored

  devices.

  The devices can be specified either by bus id (0.0.abcd) or, for 2.4 backward

  compatibility, by the device number in hexadecimal (0xabcd or abcd).

  The devices can be specified either by bus id (0.x.abcd) or, for 2.4 backward

  compatibility, by the device number in hexadecimal (0xabcd or abcd). Device

  numbers given as 0xabcd will be interpreted as 0.0.abcd.

* For some of the information present in the /proc filesystem in 2.4 (namely,

  /proc/subchannels and /proc/chpids), see driver-model.txt.

  Information formerly in /proc/irq_count is now in /proc/interrupts.

debugfs entries

---------------

* /proc/s390dbf/cio_*/ (S/390 debug feature)

* /sys/kernel/debug/s390dbf/cio_*/ (S/390 debug feature)

  Some views generated by the debug feature to hold various debug outputs.

  - /proc/s390dbf/cio_crw/sprintf

  - /sys/kernel/debug/s390dbf/cio_crw/sprintf

    Messages from the processing of pending channel report words (machine check

    handling), which will also show when CONFIG_DEBUG_CRW is defined.

    handling).

  - /proc/s390dbf/cio_msg/sprintf

    Various debug messages from the common I/O-layer; generally, messages which 

    will also show when CONFIG_DEBUG_IO is defined.

  - /sys/kernel/debug/s390dbf/cio_msg/sprintf

    Various debug messages from the common I/O-layer, including messages

    printed when cio_msg=yes.

  - /proc/s390dbf/cio_trace/hex_ascii

  - /sys/kernel/debug/s390dbf/cio_trace/hex_ascii

    Logs the calling of functions in the common I/O-layer and, if applicable, 

    which subchannel they were called for, as well as dumps of some data

    structures (like irb in an error case).

  The level of logging can be changed to be more or less verbose by piping to 

  /proc/s390dbf/cio_*/level a number between 0 and 6; see the documentation on

  the S/390 debug feature (Documentation/s390/s390dbf.txt) for details.

* For some of the information present in the /proc filesystem in 2.4 (namely,

  /proc/subchannels and /proc/chpids), see driver-model.txt.

  Information formerly in /proc/irq_count is now in /proc/interrupts.

  /sys/kernel/debug/s390dbf/cio_*/level a number between 0 and 6; see the

  documentation on the S/390 debug feature (Documentation/s390/s390dbf.txt)

  for details.

            timeout value

-EIO:       the common I/O layer terminated the request due to an error state

If the concurrent sense flag in the extended status word in the irb is set, the

field irb->scsw.count describes the number of device specific sense bytes

available in the extended control word irb->scsw.ecw[0]. No device sensing by

the device driver itself is required.

If the concurrent sense flag in the extended status word (esw) in the irb is

set, the field erw.scnt in the esw describes the number of device specific

sense bytes available in the extended control word irb->scsw.ecw[]. No device

sensing by the device driver itself is required.

The device interrupt handler can use the following definitions to investigate

the primary unit check source coded in sense byte 0 :