Commit df517985 authored by David Woodhouse's avatar David Woodhouse

Merge with

parents 0f45aa18 8b22c249
......@@ -8,7 +8,7 @@
DOCBOOKS := wanbook.xml z8530book.xml mcabook.xml videobook.xml \
kernel-hacking.xml kernel-locking.xml deviceiobook.xml \
procfs-guide.xml writing_usb_driver.xml scsidrivers.xml \
procfs-guide.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
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
"" []>
<book id="scsidrivers">
<title>SCSI Subsystem Interfaces</title>
<holder>Douglas Gilbert</holder>
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
This program is distributed in the hope that it will be
useful, but WITHOUT ANY WARRANTY; without even the implied
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.
<chapter id="intro">
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: <filename>Documentation/scsi/scsi_mid_low_api.txt</filename> .
It currently hold a little more information than this document. The
<filename>drivers/scsi/hosts.h</filename> and <filename>
drivers/scsi/scsi.h</filename> headers contain descriptions of members
of important structures for the scsi subsystem.
<chapter id="driver-struct">
<title>Driver structure</title>
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, and . It is probably best to look at what
an existing lower level driver does in this regard.
<chapter id="intfunctions">
<title>Interface Functions</title>
<chapter id="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
<chapter id="changes">
<title>Changes since lk 2.4 series</title>
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/ file. In the 2.5 series,
the scsi subsystem now has its own (much smaller) drivers/scsi/
<chapter id="credits">
The following people have contributed to this document:
Mike Anderson <email></email>
James Bottomley <email></email>
Patrick Mansfield <email></email>
Generic HDLC layer
Krzysztof Halasa <>
January, 2003
Generic HDLC layer currently supports:
- Frame Relay (ANSI, CCITT and no LMI), with ARP support (no InARP).
Normal (routed) and Ethernet-bridged (Ethernet device emulation)
interfaces can share a single PVC.
- raw HDLC - either IP (IPv4) interface or Ethernet device emulation.
- Cisco HDLC,
- PPP (uses syncppp.c),
- X.25 (uses X.25 routines).
There are hardware drivers for the following cards:
- C101 by Moxa Technologies Co., Ltd.
- RISCom/N2 by SDL Communications Inc.
- and others, some not in the official kernel.
1. Frame Relay (ANSI, CCITT, Cisco and no LMI).
- Normal (routed) and Ethernet-bridged (Ethernet device emulation)
interfaces can share a single PVC.
- ARP support (no InARP support in the kernel - there is an
experimental InARP user-space daemon available on:
2. raw HDLC - either IP (IPv4) interface or Ethernet device emulation.
3. Cisco HDLC.
4. PPP (uses syncppp.c).
5. X.25 (uses X.25 routines).
Generic HDLC is a protocol driver only - it needs a low-level driver
for your particular hardware.
Ethernet device emulation (using HDLC or Frame-Relay PVC) is compatible
with IEEE 802.1Q (VLANs) and 802.1D (Ethernet bridging).
......@@ -24,7 +24,7 @@ with IEEE 802.1Q (VLANs) and 802.1D (Ethernet bridging).
Make sure the hdlc.o and the hardware driver are loaded. It should
create a number of "hdlc" (hdlc0 etc) network devices, one for each
WAN port. You'll need the "sethdlc" utility, get it from:
Compile sethdlc.c utility:
gcc -O2 -Wall -o sethdlc sethdlc.c
......@@ -52,12 +52,12 @@ Setting interface:
* v35 | rs232 | x21 | t1 | e1 - sets physical interface for a given port
if the card has software-selectable interfaces
loopback - activate hardware loopback (for testing only)
* clock ext - external clock (uses DTE RX and TX clock)
* clock int - internal clock (provides clock signal on DCE clock output)
* clock txint - TX internal, RX external (provides TX clock on DCE output)
* clock txfromrx - TX clock derived from RX clock (TX clock on DCE output)
* rate - sets clock rate in bps (not required for external clock or
for txfromrx)
* clock ext - both RX clock and TX clock external
* clock int - both RX clock and TX clock internal
* clock txint - RX clock external, TX clock internal
* clock txfromrx - RX clock external, TX clock derived from RX clock
* rate - sets clock rate in bps (for "int" or "txint" clock only)
Setting protocol:
......@@ -79,7 +79,7 @@ Setting protocol:
* x25 - sets X.25 mode
* fr - Frame Relay mode
lmi ansi / ccitt / none - LMI (link management) type
lmi ansi / ccitt / cisco / none - LMI (link management) type
dce - Frame Relay DCE (network) side LMI instead of default DTE (user).
It has nothing to do with clocks!
t391 - link integrity verification polling timer (in seconds) - user
......@@ -119,13 +119,14 @@ or
If you have a problem with N2 or C101 card, you can issue the "private"
command to see port's packet descriptor rings (in kernel logs):
If you have a problem with N2, C101 or PLX200SYN card, you can issue the
"private" command to see port's packet descriptor rings (in kernel logs):
sethdlc hdlc0 private
The hardware driver has to be build with CONFIG_HDLC_DEBUG_RINGS.
The hardware driver has to be build with #define DEBUG_RINGS.
Attaching this info to bug reports would be helpful. Anyway, let me know
if you have problems using this.
For patches and other info look at
For patches and other info look at:
......@@ -47,7 +47,6 @@ ni52 <------------------ Buggy ------------------>
ni65 YES YES YES Software(#)
seeq NO NO NO N/A
sgiseek <------------------ Buggy ------------------>
sk_g16 NO NO YES N/A
smc-ultra YES YES YES Hardware
sunlance YES YES YES Hardware
tulip YES YES YES Hardware
......@@ -284,9 +284,6 @@ ppp.c:
seeq8005.c: *Not modularized*
(Probes ports: 0x300, 0x320, 0x340, 0x360)
sk_g16.c: *Not modularized*
(Probes ports: 0x100, 0x180, 0x208, 0x220m 0x288, 0x320, 0x328, 0x390)
skeleton.c: *Skeleton*
Release Date : Mon Mar 07 12:27:22 EST 2005 - Seokmann Ju <>
Current Version : (scsi module), (cmm module)
Older Version : (scsi module), (cmm module)
1. Added IOCTL backward compatibility.
Convert megaraid_mm driver to new compat_ioctl entry points.
I don't have easy access to hardware, so only compile tested.
- Signed-off-by:Andi Kleen <>
2. megaraid_mbox fix: wrong order of arguments in memset()
That, BTW, shows why cross-builds are useful-the only indication of
problem had been a new warning showing up in sparse output on alpha
build (number of exceeding 256 got truncated).
- Signed-off-by: Al Viro
3. Convert pci_module_init to pci_register_driver
Convert from pci_module_init to pci_register_driver
- Signed-off-by: Domen Puncer <>
4. Use the pre defined DMA mask constants from dma-mapping.h
Use the DMA_{64,32}BIT_MASK constants from dma-mapping.h when calling
pci_set_dma_mask() or pci_set_consistend_dma_mask(). See for more
Signed-off-by: Tobias Klauser <>
Signed-off-by: Domen Puncer <>
5. Remove SSID checking for Dobson, Lindsay, and Verde based products.
Checking the SSVID/SSID for controllers which have Dobson, Lindsay,
and Verde is unnecessary because device ID has been assigned by LSI
and it is unique value. So, all controllers with these IOPs have to be
supported by the driver regardless SSVID/SSID.
6. Date Thu, 27 Jan 2005 04:31:09 +0100
From Herbert Poetzl <>
Subject RFC: assert_spin_locked() for 2.6
overcautious programming will kill your kernel ;)
ever thought about checking a spin_lock or even
asserting that it must be held (maybe just for
spinlock debugging?) ...
there are several checks present in the kernel
where somebody does a variation on the following:
so what's wrong about that? nothing, unless you
compile the code with CONFIG_DEBUG_SPINLOCK but
without CONFIG_SMP ... in which case the BUG()
will kill your kernel ...
maybe it's not advised to make such assertions,
but here is a solution which works for me ...
(compile tested for sh, x86_64 and x86, boot/run
tested for x86 only)
- Herbert Poetzl <>, Thu, 27 Jan 2005
Release Date : Thu Feb 03 12:27:22 EST 2005 - Seokmann Ju <>
Current Version : (scsi module), (cmm module)
Older Version : (scsi module), (cmm module)
README for the SCSI media changer driver
This is a driver for SCSI Medium Changer devices, which are listed
with "Type: Medium Changer" in /proc/scsi/scsi.
This is for *real* Jukeboxes. It is *not* supported to work with
common small CD-ROM changers, neither one-lun-per-slot SCSI changers
nor IDE drives.
Userland tools available from here:
General Information
First some words about how changers work: A changer has 2 (possibly
more) SCSI ID's. One for the changer device which controls the robot,
and one for the device which actually reads and writes the data. The
later may be anything, a MOD, a CD-ROM, a tape or whatever. For the
changer device this is a "don't care", he *only* shuffles around the
media, nothing else.
The SCSI changer model is complex, compared to - for example - IDE-CD
changers. But it allows to handle nearly all possible cases. It knows
4 different types of changer elements:
media transport - this one shuffles around the media, i.e. the
transport arm. Also known as "picker".
storage - a slot which can hold a media.
import/export - the same as above, but is accessable from outside,
i.e. there the operator (you !) can use this to
fill in and remove media from the changer.
Sometimes named "mailslot".
data transfer - this is the device which reads/writes, i.e. the
CD-ROM / Tape / whatever drive.
None of these is limited to one: A huge Jukebox could have slots for
123 CD-ROM's, 5 CD-ROM readers (and therefore 6 SCSI ID's: the changer
and each CD-ROM) and 2 transport arms. No problem to handle.
How it is implemented
I implemented the driver as character device driver with a NetBSD-like
ioctl interface. Just grabbed NetBSD's header file and one of the
other linux SCSI device drivers as starting point. The interface
should be source code compatible with NetBSD. So if there is any
software (anybody knows ???) which supports a BSDish changer driver,
it should work with this driver too.
Over time a few more ioctls where added, volume tag support for example
wasn't covered by the NetBSD ioctl API.
Current State
Support for more than one transport arm is not implemented yet (and
nobody asked for it so far...).
I test and use the driver myself with a 35 slot cdrom jukebox from
Grundig. I got some reports telling it works ok with tape autoloaders
(Exabyte, HP and DEC). Some People use this driver with amanda. It
works fine with small (11 slots) and a huge (4 MOs, 88 slots)
magneto-optical Jukebox. Probably with lots of other changers too, most
(but not all :-) people mail me only if it does *not* work...
I don't have any device lists, neither black-list nor white-list. Thus
it is quite useless to ask me whenever a specific device is supported or
not. In theory every changer device which supports the SCSI-2 media
changer command set should work out-of-the-box with this driver. If it
doesn't, it is a bug. Either within the driver or within the firmware
of the changer device.
Using it
This is a character device with major number is 86, so use
"mknod /dev/sch0 c 86 0" to create the special file for the driver.
If the module finds the changer, it prints some messages about the
device [ try "dmesg" if you don't see anything ] and should show up in
/proc/devices. If not.... some changers use ID ? / LUN 0 for the
device and ID ? / LUN 1 for the robot mechanism. But Linux does *not*
look for LUN's other than 0 as default, becauce there are to many
broken devices. So you can try:
1) echo "scsi add-single-device 0 0 ID 1" > /proc/scsi/scsi
(replace ID with the SCSI-ID of the device)
2) boot the kernel with "max_scsi_luns=1" on the command line
(append="max_scsi_luns=1" in lilo.conf should do the trick)
If you insmod the driver with "insmod debug=1", it will be verbose and
prints a lot of stuff to the syslog. Compiling the kernel with
CONFIG_SCSI_CONSTANTS=y improves the quality of the error messages alot
because the kernel will translate the error codes into human-readable
strings then.
You can display these messages with the dmesg command (or check the
logfiles). If you email me some question becauce of a problem with the
driver, please include these messages.
Insmod options
Enable debug messages (see above, default: 0).
Be verbose (default: 1).
Send INITIALIZE ELEMENT STATUS command to the changer
at insmod time (default: 1).
timeout for the INITIALIZE ELEMENT STATUS command
(default: 3600).
timeout for all other commands (default: 120).
These two allow to specify the SCSI ID and LUN for the data
transfer elements. You likely don't need this as the jukebox
should provide this information. But some devices don't ...
These insmod options can be used to tell the driver that there
are some vendor-specific element types. Grundig for example
does this. Some jukeboxes have a printer to label fresh burned
CDs, which is addressed as element 0xc000 (type 5). To tell the
driver about this vendor-specific element, use this:
$ insmod ch \
vendor_firsts=0xc000 \
vendor_counts=1 \
All three insmod options accept up to four comma-separated
values, this way you can configure the element types 5-8.
You likely need the SCSI specs for the device in question to
find the correct values as they are not covered by the SCSI-2
I wrote this driver using the famous mailing-patches-around-the-world
method. With (more or less) help from:
Daniel Moehwald <>
Dane Jasper <>
R. Scott Bailey <>
Jonathan Corbet <>
Special thanks go to
Martin Kuehne <>
for a old, second-hand (but full functional) cdrom jukebox which I use
to develop/test driver and tools now.
Have fun,
Gerd Knorr <>
......@@ -936,8 +936,7 @@ Details:
* Returns SUCCESS if command aborted else FAILED
* Locks: struct Scsi_Host::host_lock held (with irqsave) on entry
* and assumed to be held on return.
* Locks: None held
* Calling context: kernel thread
......@@ -955,8 +954,7 @@ Details:
* Returns SUCCESS if command aborted else FAILED
* Locks: struct Scsi_Host::host_lock held (with irqsave) on entry
* and assumed to be held on return.
* Locks: None held
* Calling context: kernel thread
......@@ -974,8 +972,7 @@ Details:
* Returns SUCCESS if command aborted else FAILED
* Locks: struct Scsi_Host::host_lock held (with irqsave) on entry
* and assumed to be held on return.
* Locks: None held
* Calling context: kernel thread
......@@ -993,8 +990,7 @@ Details:
* Returns SUCCESS if command aborted else FAILED
* Locks: struct Scsi_Host::host_lock held (with irqsave) on entry
* and assumed to be held on return.
* Locks: None held
* Calling context: kernel thread
......@@ -736,6 +736,11 @@ M:
S: Maintained
P: Martin Waitz
S: Maintained