From: Christoph Hellwig Date: Sun, 15 May 2005 15:20:56 +0000 (+0200) Subject: [SCSI] remove Documentation/DocBook/scsidrivers.tmpl X-Git-Tag: v2.6.13-rc1~90^2~583^2~62^2^2~27^2~14 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=90356ac3194bf91a441a5f9c3067af386ef62462;p=linux-2.6 [SCSI] remove Documentation/DocBook/scsidrivers.tmpl This document is rather rudimentary and totally outdated. Fortunately Documentation/scsi/scsi_mid_low_api.txt replaces it quite nicely. Signed-off-by: James Bottomley --- diff --git a/Documentation/DocBook/Makefile b/Documentation/DocBook/Makefile index a221039ee4..e69d686594 100644 --- a/Documentation/DocBook/Makefile +++ b/Documentation/DocBook/Makefile @@ -9,9 +9,9 @@ DOCBOOKS := wanbook.xml z8530book.xml mcabook.xml videobook.xml \ kernel-hacking.xml kernel-locking.xml via-audio.xml \ deviceiobook.xml procfs-guide.xml tulip-user.xml \ - writing_usb_driver.xml scsidrivers.xml sis900.xml \ - kernel-api.xml journal-api.xml lsm.xml usb.xml \ - gadget.xml libata.xml mtdnand.xml librs.xml + writing_usb_driver.xml sis900.xml kernel-api.xml \ + journal-api.xml lsm.xml usb.xml gadget.xml libata.xml \ + mtdnand.xml librs.xml ### # The build process is as follows (targets): diff --git a/Documentation/DocBook/scsidrivers.tmpl b/Documentation/DocBook/scsidrivers.tmpl deleted file mode 100644 index d058e65daf..0000000000 --- a/Documentation/DocBook/scsidrivers.tmpl +++ /dev/null @@ -1,193 +0,0 @@ - - - - - - SCSI Subsystem Interfaces - - - - Douglas - Gilbert - -
- dgilbert@interlog.com -
- - - - 2003-08-11 - - - 2002 - 2003 - Douglas Gilbert - - - - - 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 outlines the interface between the Linux scsi mid level -and lower level drivers. Lower level drivers are variously called HBA -(host bus adapter) drivers, host drivers (HD) or pseudo adapter drivers. -The latter alludes to the fact that a lower level driver may be a -bridge to another IO subsystem (and the "ide-scsi" driver is an example -of this). There can be many lower level drivers active in a running -system, but only one per hardware type. For example, the aic7xxx driver -controls adaptec controllers based on the 7xxx chip series. Most lower -level drivers can control one or more scsi hosts (a.k.a. scsi initiators). - - -This document can been found in an ASCII text file in the linux kernel -source: Documentation/scsi/scsi_mid_low_api.txt . -It currently hold a little more information than this document. The -drivers/scsi/hosts.h and -drivers/scsi/scsi.h headers contain descriptions of members -of important structures for the scsi subsystem. - - - - - Driver structure - -Traditionally a lower level driver for the scsi subsystem has been -at least two files in the drivers/scsi directory. For example, a -driver called "xyz" has a header file "xyz.h" and a source file -"xyz.c". [Actually there is no good reason why this couldn't all -be in one file.] Some drivers that have been ported to several operating -systems (e.g. aic7xxx which has separate files for generic and -OS-specific code) have more than two files. Such drivers tend to have -their own directory under the drivers/scsi directory. - - -scsi_module.c is normally included at the end of a lower -level driver. For it to work a declaration like this is needed before -it is included: - - static Scsi_Host_Template driver_template = DRIVER_TEMPLATE; - /* DRIVER_TEMPLATE should contain pointers to supported interface - functions. Scsi_Host_Template is defined hosts.h */ - #include "scsi_module.c" - - - -The scsi_module.c assumes the name "driver_template" is appropriately -defined. It contains 2 functions: - - - init_this_scsi_driver() called during builtin and module driver - initialization: invokes mid level's scsi_register_host() - - - exit_this_scsi_driver() called during closedown: invokes - mid level's scsi_unregister_host() - - - - -When a new, lower level driver is being added to Linux, the following -files (all found in the drivers/scsi directory) will need some attention: -Makefile, Config.help and Config.in . It is probably best to look at what -an existing lower level driver does in this regard. - - - - - Interface Functions -!EDocumentation/scsi/scsi_mid_low_api.txt - - - - Locks - -Each Scsi_Host instance has a spin_lock called Scsi_Host::default_lock -which is initialized in scsi_register() [found in hosts.c]. Within the -same function the Scsi_Host::host_lock pointer is initialized to point -at default_lock with the scsi_assign_lock() function. Thereafter -lock and unlock operations performed by the mid level use the -Scsi_Host::host_lock pointer. - - -Lower level drivers can override the use of Scsi_Host::default_lock by -using scsi_assign_lock(). The earliest opportunity to do this would -be in the detect() function after it has invoked scsi_register(). It -could be replaced by a coarser grain lock (e.g. per driver) or a -lock of equal granularity (i.e. per host). Using finer grain locks -(e.g. per scsi device) may be possible by juggling locks in -queuecommand(). - - - - - Changes since lk 2.4 series - -io_request_lock has been replaced by several finer grained locks. The lock -relevant to lower level drivers is Scsi_Host::host_lock and there is one -per scsi host. - - -The older error handling mechanism has been removed. This means the -lower level interface functions abort() and reset() have been removed. - - -In the 2.4 series the scsi subsystem configuration descriptions were -aggregated with the configuration descriptions from all other Linux -subsystems in the Documentation/Configure.help file. In the 2.5 series, -the scsi subsystem now has its own (much smaller) drivers/scsi/Config.help -file. - - - - - Credits - -The following people have contributed to this document: - - -Mike Anderson andmike@us.ibm.com - - -James Bottomley James.Bottomley@steeleye.com - - -Patrick Mansfield patmans@us.ibm.com - - - - - -