From 849369d6c66d3054688672f97d31fceb8e8230fb Mon Sep 17 00:00:00 2001 From: root Date: Fri, 25 Dec 2015 04:40:36 +0000 Subject: initial_commit --- Documentation/DocBook/s390-drivers.tmpl | 161 ++++++++++++++++++++++++++++++++ 1 file changed, 161 insertions(+) create mode 100644 Documentation/DocBook/s390-drivers.tmpl (limited to 'Documentation/DocBook/s390-drivers.tmpl') diff --git a/Documentation/DocBook/s390-drivers.tmpl b/Documentation/DocBook/s390-drivers.tmpl new file mode 100644 index 00000000..95bfc12e --- /dev/null +++ b/Documentation/DocBook/s390-drivers.tmpl @@ -0,0 +1,161 @@ + + + + + + Writing s390 channel device drivers + + + + Cornelia + Huck + +
+ cornelia.huck@de.ibm.com +
+ + + + + + 2007 + IBM Corp. + + + + + This documentation is free software; you can redistribute + it and/or modify it under the terms of the GNU General Public + License as published by the Free Software Foundation; either + version 2 of the License, or (at your option) any later + version. + + + + This program is distributed in the hope that it will be + useful, but WITHOUT ANY WARRANTY; without even the implied + warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + See the GNU General Public License for more details. + + + + You should have received a copy of the GNU General Public + License along with this program; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, + MA 02111-1307 USA + + + + For more details see the file COPYING in the source + distribution of Linux. + + + + + + + + Introduction + + This document describes the interfaces available for device drivers that + drive s390 based channel attached I/O devices. This includes interfaces for + interaction with the hardware and interfaces for interacting with the + common driver core. Those interfaces are provided by the s390 common I/O + layer. + + + The document assumes a familarity with the technical terms associated + with the s390 channel I/O architecture. For a description of this + architecture, please refer to the "z/Architecture: Principles of + Operation", IBM publication no. SA22-7832. + + + While most I/O devices on a s390 system are typically driven through the + channel I/O mechanism described here, there are various other methods + (like the diag interface). These are out of the scope of this document. + + + Some additional information can also be found in the kernel source + under Documentation/s390/driver-model.txt. + + + + The ccw bus + + The ccw bus typically contains the majority of devices available to + a s390 system. Named after the channel command word (ccw), the basic + command structure used to address its devices, the ccw bus contains + so-called channel attached devices. They are addressed via I/O + subchannels, visible on the css bus. A device driver for + channel-attached devices, however, will never interact with the + subchannel directly, but only via the I/O device on the ccw bus, + the ccw device. + + + I/O functions for channel-attached devices + + Some hardware structures have been translated into C structures for use + by the common I/O layer and device drivers. For more information on + the hardware structures represented here, please consult the Principles + of Operation. + +!Iarch/s390/include/asm/cio.h + + + ccw devices + + Devices that want to initiate channel I/O need to attach to the ccw bus. + Interaction with the driver core is done via the common I/O layer, which + provides the abstractions of ccw devices and ccw device drivers. + + + The functions that initiate or terminate channel I/O all act upon a + ccw device structure. Device drivers must not bypass those functions + or strange side effects may happen. + +!Iarch/s390/include/asm/ccwdev.h +!Edrivers/s390/cio/device.c +!Edrivers/s390/cio/device_ops.c + + + The channel-measurement facility + + The channel-measurement facility provides a means to collect + measurement data which is made available by the channel subsystem + for each channel attached device. + +!Iarch/s390/include/asm/cmb.h +!Edrivers/s390/cio/cmf.c + + + + + The ccwgroup bus + + The ccwgroup bus only contains artificial devices, created by the user. + Many networking devices (e.g. qeth) are in fact composed of several + ccw devices (like read, write and data channel for qeth). The + ccwgroup bus provides a mechanism to create a meta-device which + contains those ccw devices as slave devices and can be associated + with the netdevice. + + + ccw group devices +!Iarch/s390/include/asm/ccwgroup.h +!Edrivers/s390/cio/ccwgroup.c + + + + + Generic interfaces + + Some interfaces are available to other drivers that do not necessarily + have anything to do with the busses described above, but still are + indirectly using basic infrastructure in the common I/O layer. + One example is the support for adapter interrupts. + +!Edrivers/s390/cio/airq.c + + + -- cgit v1.2.3