diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2008-01-25 20:19:08 -0500 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-01-25 20:19:08 -0500 |
commit | 9b73e76f3cf63379dcf45fcd4f112f5812418d0a (patch) | |
tree | 4e6bef87cd0cd6d848fc39a5ae25b981dbbe035b /Documentation/DocBook/scsi.tmpl | |
parent | 50d9a126240f9961cfdd063336bbeb91f77a7dce (diff) | |
parent | 23c3e290fb9ce38cabc2822b47583fc8702411bf (diff) |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6: (200 commits)
[SCSI] usbstorage: use last_sector_bug flag universally
[SCSI] libsas: abstract STP task status into a function
[SCSI] ultrastor: clean up inline asm warnings
[SCSI] aic7xxx: fix firmware build
[SCSI] aacraid: fib context lock for management ioctls
[SCSI] ch: remove forward declarations
[SCSI] ch: fix device minor number management bug
[SCSI] ch: handle class_device_create failure properly
[SCSI] NCR5380: fix section mismatch
[SCSI] sg: fix /proc/scsi/sg/devices when no SCSI devices
[SCSI] IB/iSER: add logical unit reset support
[SCSI] don't use __GFP_DMA for sense buffers if not required
[SCSI] use dynamically allocated sense buffer
[SCSI] scsi.h: add macro for enclosure bit of inquiry data
[SCSI] sd: add fix for devices with last sector access problems
[SCSI] fix pcmcia compile problem
[SCSI] aacraid: add Voodoo Lite class of cards.
[SCSI] aacraid: add new driver features flags
[SCSI] qla2xxx: Update version number to 8.02.00-k7.
[SCSI] qla2xxx: Issue correct MBC_INITIALIZE_FIRMWARE command.
...
Diffstat (limited to 'Documentation/DocBook/scsi.tmpl')
-rw-r--r-- | Documentation/DocBook/scsi.tmpl | 409 |
1 files changed, 409 insertions, 0 deletions
diff --git a/Documentation/DocBook/scsi.tmpl b/Documentation/DocBook/scsi.tmpl new file mode 100644 index 000000000000..f299ab182bbe --- /dev/null +++ b/Documentation/DocBook/scsi.tmpl | |||
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1 | <?xml version="1.0" encoding="UTF-8"?> | ||
2 | <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" | ||
3 | "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> | ||
4 | |||
5 | <book id="scsimid"> | ||
6 | <bookinfo> | ||
7 | <title>SCSI Interfaces Guide</title> | ||
8 | |||
9 | <authorgroup> | ||
10 | <author> | ||
11 | <firstname>James</firstname> | ||
12 | <surname>Bottomley</surname> | ||
13 | <affiliation> | ||
14 | <address> | ||
15 | <email>James.Bottomley@steeleye.com</email> | ||
16 | </address> | ||
17 | </affiliation> | ||
18 | </author> | ||
19 | |||
20 | <author> | ||
21 | <firstname>Rob</firstname> | ||
22 | <surname>Landley</surname> | ||
23 | <affiliation> | ||
24 | <address> | ||
25 | <email>rob@landley.net</email> | ||
26 | </address> | ||
27 | </affiliation> | ||
28 | </author> | ||
29 | |||
30 | </authorgroup> | ||
31 | |||
32 | <copyright> | ||
33 | <year>2007</year> | ||
34 | <holder>Linux Foundation</holder> | ||
35 | </copyright> | ||
36 | |||
37 | <legalnotice> | ||
38 | <para> | ||
39 | This documentation is free software; you can redistribute | ||
40 | it and/or modify it under the terms of the GNU General Public | ||
41 | License version 2. | ||
42 | </para> | ||
43 | |||
44 | <para> | ||
45 | This program is distributed in the hope that it will be | ||
46 | useful, but WITHOUT ANY WARRANTY; without even the implied | ||
47 | warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. | ||
48 | For more details see the file COPYING in the source | ||
49 | distribution of Linux. | ||
50 | </para> | ||
51 | </legalnotice> | ||
52 | </bookinfo> | ||
53 | |||
54 | <toc></toc> | ||
55 | |||
56 | <chapter id="intro"> | ||
57 | <title>Introduction</title> | ||
58 | <sect1 id="protocol_vs_bus"> | ||
59 | <title>Protocol vs bus</title> | ||
60 | <para> | ||
61 | Once upon a time, the Small Computer Systems Interface defined both | ||
62 | a parallel I/O bus and a data protocol to connect a wide variety of | ||
63 | peripherals (disk drives, tape drives, modems, printers, scanners, | ||
64 | optical drives, test equipment, and medical devices) to a host | ||
65 | computer. | ||
66 | </para> | ||
67 | <para> | ||
68 | Although the old parallel (fast/wide/ultra) SCSI bus has largely | ||
69 | fallen out of use, the SCSI command set is more widely used than ever | ||
70 | to communicate with devices over a number of different busses. | ||
71 | </para> | ||
72 | <para> | ||
73 | The <ulink url='http://www.t10.org/scsi-3.htm'>SCSI protocol</ulink> | ||
74 | is a big-endian peer-to-peer packet based protocol. SCSI commands | ||
75 | are 6, 10, 12, or 16 bytes long, often followed by an associated data | ||
76 | payload. | ||
77 | </para> | ||
78 | <para> | ||
79 | SCSI commands can be transported over just about any kind of bus, and | ||
80 | are the default protocol for storage devices attached to USB, SATA, | ||
81 | SAS, Fibre Channel, FireWire, and ATAPI devices. SCSI packets are | ||
82 | also commonly exchanged over Infiniband, | ||
83 | <ulink url='http://i2o.shadowconnect.com/faq.php'>I20</ulink>, TCP/IP | ||
84 | (<ulink url='http://en.wikipedia.org/wiki/ISCSI'>iSCSI</ulink>), even | ||
85 | <ulink url='http://cyberelk.net/tim/parport/parscsi.html'>Parallel | ||
86 | ports</ulink>. | ||
87 | </para> | ||
88 | </sect1> | ||
89 | <sect1 id="subsystem_design"> | ||
90 | <title>Design of the Linux SCSI subsystem</title> | ||
91 | <para> | ||
92 | The SCSI subsystem uses a three layer design, with upper, mid, and low | ||
93 | layers. Every operation involving the SCSI subsystem (such as reading | ||
94 | a sector from a disk) uses one driver at each of the 3 levels: one | ||
95 | upper layer driver, one lower layer driver, and the SCSI midlayer. | ||
96 | </para> | ||
97 | <para> | ||
98 | The SCSI upper layer provides the interface between userspace and the | ||
99 | kernel, in the form of block and char device nodes for I/O and | ||
100 | ioctl(). The SCSI lower layer contains drivers for specific hardware | ||
101 | devices. | ||
102 | </para> | ||
103 | <para> | ||
104 | In between is the SCSI mid-layer, analogous to a network routing | ||
105 | layer such as the IPv4 stack. The SCSI mid-layer routes a packet | ||
106 | based data protocol between the upper layer's /dev nodes and the | ||
107 | corresponding devices in the lower layer. It manages command queues, | ||
108 | provides error handling and power management functions, and responds | ||
109 | to ioctl() requests. | ||
110 | </para> | ||
111 | </sect1> | ||
112 | </chapter> | ||
113 | |||
114 | <chapter id="upper_layer"> | ||
115 | <title>SCSI upper layer</title> | ||
116 | <para> | ||
117 | The upper layer supports the user-kernel interface by providing | ||
118 | device nodes. | ||
119 | </para> | ||
120 | <sect1 id="sd"> | ||
121 | <title>sd (SCSI Disk)</title> | ||
122 | <para>sd (sd_mod.o)</para> | ||
123 | <!-- !Idrivers/scsi/sd.c --> | ||
124 | </sect1> | ||
125 | <sect1 id="sr"> | ||
126 | <title>sr (SCSI CD-ROM)</title> | ||
127 | <para>sr (sr_mod.o)</para> | ||
128 | </sect1> | ||
129 | <sect1 id="st"> | ||
130 | <title>st (SCSI Tape)</title> | ||
131 | <para>st (st.o)</para> | ||
132 | </sect1> | ||
133 | <sect1 id="sg"> | ||
134 | <title>sg (SCSI Generic)</title> | ||
135 | <para>sg (sg.o)</para> | ||
136 | </sect1> | ||
137 | <sect1 id="ch"> | ||
138 | <title>ch (SCSI Media Changer)</title> | ||
139 | <para>ch (ch.c)</para> | ||
140 | </sect1> | ||
141 | </chapter> | ||
142 | |||
143 | <chapter id="mid_layer"> | ||
144 | <title>SCSI mid layer</title> | ||
145 | |||
146 | <sect1 id="midlayer_implementation"> | ||
147 | <title>SCSI midlayer implementation</title> | ||
148 | <sect2 id="scsi_device.h"> | ||
149 | <title>include/scsi/scsi_device.h</title> | ||
150 | <para> | ||
151 | </para> | ||
152 | !Iinclude/scsi/scsi_device.h | ||
153 | </sect2> | ||
154 | |||
155 | <sect2 id="scsi.c"> | ||
156 | <title>drivers/scsi/scsi.c</title> | ||
157 | <para>Main file for the SCSI midlayer.</para> | ||
158 | !Edrivers/scsi/scsi.c | ||
159 | </sect2> | ||
160 | <sect2 id="scsicam.c"> | ||
161 | <title>drivers/scsi/scsicam.c</title> | ||
162 | <para> | ||
163 | <ulink url='http://www.t10.org/ftp/t10/drafts/cam/cam-r12b.pdf'>SCSI | ||
164 | Common Access Method</ulink> support functions, for use with | ||
165 | HDIO_GETGEO, etc. | ||
166 | </para> | ||
167 | !Edrivers/scsi/scsicam.c | ||
168 | </sect2> | ||
169 | <sect2 id="scsi_error.c"> | ||
170 | <title>drivers/scsi/scsi_error.c</title> | ||
171 | <para>Common SCSI error/timeout handling routines.</para> | ||
172 | !Edrivers/scsi/scsi_error.c | ||
173 | </sect2> | ||
174 | <sect2 id="scsi_devinfo.c"> | ||
175 | <title>drivers/scsi/scsi_devinfo.c</title> | ||
176 | <para> | ||
177 | Manage scsi_dev_info_list, which tracks blacklisted and whitelisted | ||
178 | devices. | ||
179 | </para> | ||
180 | !Idrivers/scsi/scsi_devinfo.c | ||
181 | </sect2> | ||
182 | <sect2 id="scsi_ioctl.c"> | ||
183 | <title>drivers/scsi/scsi_ioctl.c</title> | ||
184 | <para> | ||
185 | Handle ioctl() calls for SCSI devices. | ||
186 | </para> | ||
187 | !Edrivers/scsi/scsi_ioctl.c | ||
188 | </sect2> | ||
189 | <sect2 id="scsi_lib.c"> | ||
190 | <title>drivers/scsi/scsi_lib.c</title> | ||
191 | <para> | ||
192 | SCSI queuing library. | ||
193 | </para> | ||
194 | !Edrivers/scsi/scsi_lib.c | ||
195 | </sect2> | ||
196 | <sect2 id="scsi_lib_dma.c"> | ||
197 | <title>drivers/scsi/scsi_lib_dma.c</title> | ||
198 | <para> | ||
199 | SCSI library functions depending on DMA | ||
200 | (map and unmap scatter-gather lists). | ||
201 | </para> | ||
202 | !Edrivers/scsi/scsi_lib_dma.c | ||
203 | </sect2> | ||
204 | <sect2 id="scsi_module.c"> | ||
205 | <title>drivers/scsi/scsi_module.c</title> | ||
206 | <para> | ||
207 | The file drivers/scsi/scsi_module.c contains legacy support for | ||
208 | old-style host templates. It should never be used by any new driver. | ||
209 | </para> | ||
210 | </sect2> | ||
211 | <sect2 id="scsi_proc.c"> | ||
212 | <title>drivers/scsi/scsi_proc.c</title> | ||
213 | <para> | ||
214 | The functions in this file provide an interface between | ||
215 | the PROC file system and the SCSI device drivers | ||
216 | It is mainly used for debugging, statistics and to pass | ||
217 | information directly to the lowlevel driver. | ||
218 | |||
219 | I.E. plumbing to manage /proc/scsi/* | ||
220 | </para> | ||
221 | !Idrivers/scsi/scsi_proc.c | ||
222 | </sect2> | ||
223 | <sect2 id="scsi_netlink.c"> | ||
224 | <title>drivers/scsi/scsi_netlink.c</title> | ||
225 | <para> | ||
226 | Infrastructure to provide async events from transports to userspace | ||
227 | via netlink, using a single NETLINK_SCSITRANSPORT protocol for all | ||
228 | transports. | ||
229 | |||
230 | See <ulink url='http://marc.info/?l=linux-scsi&m=115507374832500&w=2'>the | ||
231 | original patch submission</ulink> for more details. | ||
232 | </para> | ||
233 | !Idrivers/scsi/scsi_netlink.c | ||
234 | </sect2> | ||
235 | <sect2 id="scsi_scan.c"> | ||
236 | <title>drivers/scsi/scsi_scan.c</title> | ||
237 | <para> | ||
238 | Scan a host to determine which (if any) devices are attached. | ||
239 | |||
240 | The general scanning/probing algorithm is as follows, exceptions are | ||
241 | made to it depending on device specific flags, compilation options, | ||
242 | and global variable (boot or module load time) settings. | ||
243 | |||
244 | A specific LUN is scanned via an INQUIRY command; if the LUN has a | ||
245 | device attached, a scsi_device is allocated and setup for it. | ||
246 | |||
247 | For every id of every channel on the given host, start by scanning | ||
248 | LUN 0. Skip hosts that don't respond at all to a scan of LUN 0. | ||
249 | Otherwise, if LUN 0 has a device attached, allocate and setup a | ||
250 | scsi_device for it. If target is SCSI-3 or up, issue a REPORT LUN, | ||
251 | and scan all of the LUNs returned by the REPORT LUN; else, | ||
252 | sequentially scan LUNs up until some maximum is reached, or a LUN is | ||
253 | seen that cannot have a device attached to it. | ||
254 | </para> | ||
255 | !Idrivers/scsi/scsi_scan.c | ||
256 | </sect2> | ||
257 | <sect2 id="scsi_sysctl.c"> | ||
258 | <title>drivers/scsi/scsi_sysctl.c</title> | ||
259 | <para> | ||
260 | Set up the sysctl entry: "/dev/scsi/logging_level" | ||
261 | (DEV_SCSI_LOGGING_LEVEL) which sets/returns scsi_logging_level. | ||
262 | </para> | ||
263 | </sect2> | ||
264 | <sect2 id="scsi_sysfs.c"> | ||
265 | <title>drivers/scsi/scsi_sysfs.c</title> | ||
266 | <para> | ||
267 | SCSI sysfs interface routines. | ||
268 | </para> | ||
269 | !Edrivers/scsi/scsi_sysfs.c | ||
270 | </sect2> | ||
271 | <sect2 id="hosts.c"> | ||
272 | <title>drivers/scsi/hosts.c</title> | ||
273 | <para> | ||
274 | mid to lowlevel SCSI driver interface | ||
275 | </para> | ||
276 | !Edrivers/scsi/hosts.c | ||
277 | </sect2> | ||
278 | <sect2 id="constants.c"> | ||
279 | <title>drivers/scsi/constants.c</title> | ||
280 | <para> | ||
281 | mid to lowlevel SCSI driver interface | ||
282 | </para> | ||
283 | !Edrivers/scsi/constants.c | ||
284 | </sect2> | ||
285 | </sect1> | ||
286 | |||
287 | <sect1 id="Transport_classes"> | ||
288 | <title>Transport classes</title> | ||
289 | <para> | ||
290 | Transport classes are service libraries for drivers in the SCSI | ||
291 | lower layer, which expose transport attributes in sysfs. | ||
292 | </para> | ||
293 | <sect2 id="Fibre_Channel_transport"> | ||
294 | <title>Fibre Channel transport</title> | ||
295 | <para> | ||
296 | The file drivers/scsi/scsi_transport_fc.c defines transport attributes | ||
297 | for Fibre Channel. | ||
298 | </para> | ||
299 | !Edrivers/scsi/scsi_transport_fc.c | ||
300 | </sect2> | ||
301 | <sect2 id="iSCSI_transport"> | ||
302 | <title>iSCSI transport class</title> | ||
303 | <para> | ||
304 | The file drivers/scsi/scsi_transport_iscsi.c defines transport | ||
305 | attributes for the iSCSI class, which sends SCSI packets over TCP/IP | ||
306 | connections. | ||
307 | </para> | ||
308 | !Edrivers/scsi/scsi_transport_iscsi.c | ||
309 | </sect2> | ||
310 | <sect2 id="SAS_transport"> | ||
311 | <title>Serial Attached SCSI (SAS) transport class</title> | ||
312 | <para> | ||
313 | The file drivers/scsi/scsi_transport_sas.c defines transport | ||
314 | attributes for Serial Attached SCSI, a variant of SATA aimed at | ||
315 | large high-end systems. | ||
316 | </para> | ||
317 | <para> | ||
318 | The SAS transport class contains common code to deal with SAS HBAs, | ||
319 | an aproximated representation of SAS topologies in the driver model, | ||
320 | and various sysfs attributes to expose these topologies and managment | ||
321 | interfaces to userspace. | ||
322 | </para> | ||
323 | <para> | ||
324 | In addition to the basic SCSI core objects this transport class | ||
325 | introduces two additional intermediate objects: The SAS PHY | ||
326 | as represented by struct sas_phy defines an "outgoing" PHY on | ||
327 | a SAS HBA or Expander, and the SAS remote PHY represented by | ||
328 | struct sas_rphy defines an "incoming" PHY on a SAS Expander or | ||
329 | end device. Note that this is purely a software concept, the | ||
330 | underlying hardware for a PHY and a remote PHY is the exactly | ||
331 | the same. | ||
332 | </para> | ||
333 | <para> | ||
334 | There is no concept of a SAS port in this code, users can see | ||
335 | what PHYs form a wide port based on the port_identifier attribute, | ||
336 | which is the same for all PHYs in a port. | ||
337 | </para> | ||
338 | !Edrivers/scsi/scsi_transport_sas.c | ||
339 | </sect2> | ||
340 | <sect2 id="SATA_transport"> | ||
341 | <title>SATA transport class</title> | ||
342 | <para> | ||
343 | The SATA transport is handled by libata, which has its own book of | ||
344 | documentation in this directory. | ||
345 | </para> | ||
346 | </sect2> | ||
347 | <sect2 id="SPI_transport"> | ||
348 | <title>Parallel SCSI (SPI) transport class</title> | ||
349 | <para> | ||
350 | The file drivers/scsi/scsi_transport_spi.c defines transport | ||
351 | attributes for traditional (fast/wide/ultra) SCSI busses. | ||
352 | </para> | ||
353 | !Edrivers/scsi/scsi_transport_spi.c | ||
354 | </sect2> | ||
355 | <sect2 id="SRP_transport"> | ||
356 | <title>SCSI RDMA (SRP) transport class</title> | ||
357 | <para> | ||
358 | The file drivers/scsi/scsi_transport_srp.c defines transport | ||
359 | attributes for SCSI over Remote Direct Memory Access. | ||
360 | </para> | ||
361 | !Edrivers/scsi/scsi_transport_srp.c | ||
362 | </sect2> | ||
363 | </sect1> | ||
364 | |||
365 | </chapter> | ||
366 | |||
367 | <chapter id="lower_layer"> | ||
368 | <title>SCSI lower layer</title> | ||
369 | <sect1 id="hba_drivers"> | ||
370 | <title>Host Bus Adapter transport types</title> | ||
371 | <para> | ||
372 | Many modern device controllers use the SCSI command set as a protocol to | ||
373 | communicate with their devices through many different types of physical | ||
374 | connections. | ||
375 | </para> | ||
376 | <para> | ||
377 | In SCSI language a bus capable of carrying SCSI commands is | ||
378 | called a "transport", and a controller connecting to such a bus is | ||
379 | called a "host bus adapter" (HBA). | ||
380 | </para> | ||
381 | <sect2 id="scsi_debug.c"> | ||
382 | <title>Debug transport</title> | ||
383 | <para> | ||
384 | The file drivers/scsi/scsi_debug.c simulates a host adapter with a | ||
385 | variable number of disks (or disk like devices) attached, sharing a | ||
386 | common amount of RAM. Does a lot of checking to make sure that we are | ||
387 | not getting blocks mixed up, and panics the kernel if anything out of | ||
388 | the ordinary is seen. | ||
389 | </para> | ||
390 | <para> | ||
391 | To be more realistic, the simulated devices have the transport | ||
392 | attributes of SAS disks. | ||
393 | </para> | ||
394 | <para> | ||
395 | For documentation see | ||
396 | <ulink url='http://www.torque.net/sg/sdebug26.html'>http://www.torque.net/sg/sdebug26.html</ulink> | ||
397 | </para> | ||
398 | <!-- !Edrivers/scsi/scsi_debug.c --> | ||
399 | </sect2> | ||
400 | <sect2 id="todo"> | ||
401 | <title>todo</title> | ||
402 | <para>Parallel (fast/wide/ultra) SCSI, USB, SATA, | ||
403 | SAS, Fibre Channel, FireWire, ATAPI devices, Infiniband, | ||
404 | I20, iSCSI, Parallel ports, netlink... | ||
405 | </para> | ||
406 | </sect2> | ||
407 | </sect1> | ||
408 | </chapter> | ||
409 | </book> | ||