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Linus Torvalds1da177e2005-04-16 15:20:36 -07001<?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="LinuxKernelAPI">
6 <bookinfo>
7 <title>The Linux Kernel API</title>
8
9 <legalnotice>
10 <para>
11 This documentation is free software; you can redistribute
12 it and/or modify it under the terms of the GNU General Public
13 License as published by the Free Software Foundation; either
14 version 2 of the License, or (at your option) any later
15 version.
16 </para>
17
18 <para>
19 This program is distributed in the hope that it will be
20 useful, but WITHOUT ANY WARRANTY; without even the implied
21 warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
22 See the GNU General Public License for more details.
23 </para>
24
25 <para>
26 You should have received a copy of the GNU General Public
27 License along with this program; if not, write to the Free
28 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
29 MA 02111-1307 USA
30 </para>
31
32 <para>
33 For more details see the file COPYING in the source
34 distribution of Linux.
35 </para>
36 </legalnotice>
37 </bookinfo>
38
39<toc></toc>
40
41 <chapter id="Basics">
42 <title>Driver Basics</title>
43 <sect1><title>Driver Entry and Exit points</title>
44!Iinclude/linux/init.h
45 </sect1>
46
47 <sect1><title>Atomic and pointer manipulation</title>
Randy Dunlapf3cf31a2007-10-12 21:17:23 -070048!Iinclude/asm-x86/atomic_32.h
Randy Dunlap8f731f72007-10-18 23:39:28 -070049!Iinclude/asm-x86/unaligned.h
Linus Torvalds1da177e2005-04-16 15:20:36 -070050 </sect1>
51
Linus Torvalds1da177e2005-04-16 15:20:36 -070052 <sect1><title>Delaying, scheduling, and timer routines</title>
Pavel Pisa4dc3b162005-05-01 08:59:25 -070053!Iinclude/linux/sched.h
54!Ekernel/sched.c
55!Ekernel/timer.c
Linus Torvalds1da177e2005-04-16 15:20:36 -070056 </sect1>
Thomas Gleixnerdf784882006-01-09 20:52:33 -080057 <sect1><title>High-resolution timers</title>
58!Iinclude/linux/ktime.h
59!Iinclude/linux/hrtimer.h
60!Ekernel/hrtimer.c
61 </sect1>
Rolf Eike Beer0fcb78c2006-07-30 03:03:42 -070062 <sect1><title>Workqueues and Kevents</title>
63!Ekernel/workqueue.c
64 </sect1>
Pavel Pisa4dc3b162005-05-01 08:59:25 -070065 <sect1><title>Internal Functions</title>
66!Ikernel/exit.c
67!Ikernel/signal.c
Randy Dunlap9e37bd32006-06-25 05:49:19 -070068!Iinclude/linux/kthread.h
69!Ekernel/kthread.c
Pavel Pisa4dc3b162005-05-01 08:59:25 -070070 </sect1>
71
72 <sect1><title>Kernel objects manipulation</title>
73<!--
74X!Iinclude/linux/kobject.h
75-->
76!Elib/kobject.c
77 </sect1>
78
79 <sect1><title>Kernel utility functions</title>
80!Iinclude/linux/kernel.h
Martin Waitzddad86c2005-11-13 16:08:14 -080081!Ekernel/printk.c
Pavel Pisa4dc3b162005-05-01 08:59:25 -070082!Ekernel/panic.c
83!Ekernel/sys.c
84!Ekernel/rcupdate.c
85 </sect1>
86
Randy Dunlapd3e69752007-05-09 07:02:59 +020087 <sect1><title>Device Resource Management</title>
88!Edrivers/base/devres.c
89 </sect1>
90
Linus Torvalds1da177e2005-04-16 15:20:36 -070091 </chapter>
92
93 <chapter id="adt">
94 <title>Data Types</title>
95 <sect1><title>Doubly Linked Lists</title>
96!Iinclude/linux/list.h
97 </sect1>
98 </chapter>
99
100 <chapter id="libc">
101 <title>Basic C Library Functions</title>
102
103 <para>
104 When writing drivers, you cannot in general use routines which are
105 from the C Library. Some of the functions have been found generally
106 useful and they are listed below. The behaviour of these functions
107 may vary slightly from those defined by ANSI, and these deviations
108 are noted in the text.
109 </para>
110
111 <sect1><title>String Conversions</title>
112!Ilib/vsprintf.c
113!Elib/vsprintf.c
114 </sect1>
115 <sect1><title>String Manipulation</title>
Pavel Pisa4dc3b162005-05-01 08:59:25 -0700116<!-- All functions are exported at now
117X!Ilib/string.c
118 -->
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119!Elib/string.c
120 </sect1>
121 <sect1><title>Bit Operations</title>
Randy Dunlapf3cf31a2007-10-12 21:17:23 -0700122!Iinclude/asm-x86/bitops_32.h
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123 </sect1>
Randy Dunlap28e83ba2006-06-25 05:48:58 -0700124 </chapter>
125
126 <chapter id="kernel-lib">
127 <title>Basic Kernel Library Functions</title>
128
129 <para>
130 The Linux kernel provides more basic utility functions.
131 </para>
132
Randy Dunlap6e1907ff2006-06-25 05:48:57 -0700133 <sect1><title>Bitmap Operations</title>
134!Elib/bitmap.c
135!Ilib/bitmap.c
136 </sect1>
Randy Dunlap28e83ba2006-06-25 05:48:58 -0700137
138 <sect1><title>Command-line Parsing</title>
139!Elib/cmdline.c
140 </sect1>
Randy Dunlap2f721002006-06-25 05:48:59 -0700141
Jan Nikitenkoad241522007-07-17 04:04:03 -0700142 <sect1 id="crc"><title>CRC Functions</title>
143!Elib/crc7.c
Randy Dunlap2f721002006-06-25 05:48:59 -0700144!Elib/crc16.c
Jan Nikitenkoad241522007-07-17 04:04:03 -0700145!Elib/crc-itu-t.c
Randy Dunlap2f721002006-06-25 05:48:59 -0700146!Elib/crc32.c
147!Elib/crc-ccitt.c
148 </sect1>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 </chapter>
150
151 <chapter id="mm">
152 <title>Memory Management in Linux</title>
153 <sect1><title>The Slab Cache</title>
Paul Drynoff800590f2006-06-23 02:03:48 -0700154!Iinclude/linux/slab.h
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155!Emm/slab.c
156 </sect1>
157 <sect1><title>User Space Memory Access</title>
Randy Dunlapf3cf31a2007-10-12 21:17:23 -0700158!Iinclude/asm-x86/uaccess_32.h
159!Earch/x86/lib/usercopy_32.c
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160 </sect1>
Pavel Pisa4dc3b162005-05-01 08:59:25 -0700161 <sect1><title>More Memory Management Functions</title>
Pavel Pisa4dc3b162005-05-01 08:59:25 -0700162!Emm/readahead.c
163!Emm/filemap.c
164!Emm/memory.c
165!Emm/vmalloc.c
Randy Dunlap88ca3b92006-10-04 02:15:25 -0700166!Imm/page_alloc.c
Pavel Pisa4dc3b162005-05-01 08:59:25 -0700167!Emm/mempool.c
168!Emm/page-writeback.c
169!Emm/truncate.c
170 </sect1>
171 </chapter>
172
173
174 <chapter id="ipc">
175 <title>Kernel IPC facilities</title>
176
177 <sect1><title>IPC utilities</title>
178!Iipc/util.c
179 </sect1>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180 </chapter>
181
182 <chapter id="kfifo">
183 <title>FIFO Buffer</title>
184 <sect1><title>kfifo interface</title>
185!Iinclude/linux/kfifo.h
186!Ekernel/kfifo.c
187 </sect1>
188 </chapter>
189
Randy Dunlap5b217fa2006-09-29 01:59:10 -0700190 <chapter id="relayfs">
191 <title>relay interface support</title>
192
193 <para>
194 Relay interface support
195 is designed to provide an efficient mechanism for tools and
196 facilities to relay large amounts of data from kernel space to
197 user space.
198 </para>
199
200 <sect1><title>relay interface</title>
201!Ekernel/relay.c
202!Ikernel/relay.c
203 </sect1>
204 </chapter>
205
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206 <chapter id="netcore">
207 <title>Linux Networking</title>
Pavel Pisa4dc3b162005-05-01 08:59:25 -0700208 <sect1><title>Networking Base Types</title>
209!Iinclude/linux/net.h
210 </sect1>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211 <sect1><title>Socket Buffer Functions</title>
212!Iinclude/linux/skbuff.h
Pavel Pisa4dc3b162005-05-01 08:59:25 -0700213!Iinclude/net/sock.h
214!Enet/socket.c
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215!Enet/core/skbuff.c
Pavel Pisa4dc3b162005-05-01 08:59:25 -0700216!Enet/core/sock.c
217!Enet/core/datagram.c
218!Enet/core/stream.c
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219 </sect1>
220 <sect1><title>Socket Filter</title>
221!Enet/core/filter.c
222 </sect1>
223 <sect1><title>Generic Network Statistics</title>
224!Iinclude/linux/gen_stats.h
225!Enet/core/gen_stats.c
226!Enet/core/gen_estimator.c
227 </sect1>
Pavel Pisa4dc3b162005-05-01 08:59:25 -0700228 <sect1><title>SUN RPC subsystem</title>
229<!-- The !D functionality is not perfect, garbage has to be protected by comments
230!Dnet/sunrpc/sunrpc_syms.c
231-->
232!Enet/sunrpc/xdr.c
233!Enet/sunrpc/svcsock.c
234!Enet/sunrpc/sched.c
235 </sect1>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236 </chapter>
237
238 <chapter id="netdev">
239 <title>Network device support</title>
240 <sect1><title>Driver Support</title>
241!Enet/core/dev.c
Stephen Hemmingerc2da8ac2005-11-01 17:05:09 -0800242!Enet/ethernet/eth.c
Stephen Hemmingerbea33482007-10-03 16:41:36 -0700243!Enet/sched/sch_generic.c
Randy Dunlap461ddf32005-11-20 21:25:15 -0800244!Iinclude/linux/etherdevice.h
Stephen Hemmingerbea33482007-10-03 16:41:36 -0700245!Iinclude/linux/netdevice.h
246 </sect1>
247 <sect1><title>PHY Support</title>
Randy Dunlapb3df0da2007-03-06 02:41:48 -0800248!Edrivers/net/phy/phy.c
249!Idrivers/net/phy/phy.c
250!Edrivers/net/phy/phy_device.c
251!Idrivers/net/phy/phy_device.c
252!Edrivers/net/phy/mdio_bus.c
253!Idrivers/net/phy/mdio_bus.c
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254 </sect1>
Stephen Hemmingerbea33482007-10-03 16:41:36 -0700255<!-- FIXME: Removed for now since no structured comments in source
256 <sect1><title>Wireless</title>
257X!Enet/core/wireless.c
258 </sect1>
259-->
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260 <sect1><title>Synchronous PPP</title>
261!Edrivers/net/wan/syncppp.c
262 </sect1>
263 </chapter>
264
265 <chapter id="modload">
266 <title>Module Support</title>
267 <sect1><title>Module Loading</title>
268!Ekernel/kmod.c
269 </sect1>
270 <sect1><title>Inter Module support</title>
271 <para>
272 Refer to the file kernel/module.c for more information.
273 </para>
274<!-- FIXME: Removed for now since no structured comments in source
275X!Ekernel/module.c
276-->
277 </sect1>
278 </chapter>
279
280 <chapter id="hardware">
281 <title>Hardware Interfaces</title>
282 <sect1><title>Interrupt Handling</title>
Randy Dunlap8f2709b2005-11-07 01:01:05 -0800283!Ekernel/irq/manage.c
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284 </sect1>
285
Randy Dunlapeed34d02006-10-03 01:13:50 -0700286 <sect1><title>DMA Channels</title>
287!Ekernel/dma.c
288 </sect1>
289
Pavel Pisa4dc3b162005-05-01 08:59:25 -0700290 <sect1><title>Resources Management</title>
Randy Dunlap2b549602006-07-30 03:03:40 -0700291!Ikernel/resource.c
Randy Dunlape1ca66d2006-10-03 01:13:51 -0700292!Ekernel/resource.c
Pavel Pisa4dc3b162005-05-01 08:59:25 -0700293 </sect1>
294
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295 <sect1><title>MTRR Handling</title>
Randy Dunlapf3cf31a2007-10-12 21:17:23 -0700296!Earch/x86/kernel/cpu/mtrr/main.c
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297 </sect1>
Randy Dunlapb0ef3712006-06-25 05:49:18 -0700298
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299 <sect1><title>PCI Support Library</title>
300!Edrivers/pci/pci.c
Pavel Pisa4dc3b162005-05-01 08:59:25 -0700301!Edrivers/pci/pci-driver.c
302!Edrivers/pci/remove.c
303!Edrivers/pci/pci-acpi.c
Randy Dunlapd75763d2006-07-30 03:03:41 -0700304!Edrivers/pci/search.c
Pavel Pisa4dc3b162005-05-01 08:59:25 -0700305!Edrivers/pci/msi.c
306!Edrivers/pci/bus.c
Randy Dunlapf05aab82005-10-23 11:58:19 -0700307<!-- FIXME: Removed for now since no structured comments in source
308X!Edrivers/pci/hotplug.c
309-->
Pavel Pisa4dc3b162005-05-01 08:59:25 -0700310!Edrivers/pci/probe.c
311!Edrivers/pci/rom.c
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312 </sect1>
313 <sect1><title>PCI Hotplug Support Library</title>
314!Edrivers/pci/hotplug/pci_hotplug_core.c
315 </sect1>
316 <sect1><title>MCA Architecture</title>
317 <sect2><title>MCA Device Functions</title>
318 <para>
Randy Dunlapf3cf31a2007-10-12 21:17:23 -0700319 Refer to the file arch/x86/kernel/mca_32.c for more information.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320 </para>
321<!-- FIXME: Removed for now since no structured comments in source
Randy Dunlapf3cf31a2007-10-12 21:17:23 -0700322X!Earch/x86/kernel/mca_32.c
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323-->
324 </sect2>
325 <sect2><title>MCA Bus DMA</title>
Randy Dunlapf3cf31a2007-10-12 21:17:23 -0700326!Iinclude/asm-x86/mca_dma.h
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327 </sect2>
328 </sect1>
329 </chapter>
330
Randy Dunlapb0ef3712006-06-25 05:49:18 -0700331 <chapter id="firmware">
332 <title>Firmware Interfaces</title>
333 <sect1><title>DMI Interfaces</title>
334!Edrivers/firmware/dmi_scan.c
335 </sect1>
Randy Dunlap6e8c8182007-02-10 01:46:03 -0800336 <sect1><title>EDD Interfaces</title>
337!Idrivers/firmware/edd.c
338 </sect1>
Randy Dunlapb0ef3712006-06-25 05:49:18 -0700339 </chapter>
340
Linus Torvalds1da177e2005-04-16 15:20:36 -0700341 <chapter id="security">
342 <title>Security Framework</title>
James Morris20510f22007-10-16 23:31:32 -0700343!Isecurity/security.c
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344 </chapter>
345
Randy Dunlap862f5f02006-06-23 02:05:52 -0700346 <chapter id="audit">
347 <title>Audit Interfaces</title>
348!Ekernel/audit.c
349!Ikernel/auditsc.c
350!Ikernel/auditfilter.c
351 </chapter>
352
353 <chapter id="accounting">
354 <title>Accounting Framework</title>
355!Ikernel/acct.c
356 </chapter>
357
Linus Torvalds1da177e2005-04-16 15:20:36 -0700358 <chapter id="pmfuncs">
359 <title>Power Management</title>
360!Ekernel/power/pm.c
361 </chapter>
362
Pavel Pisa4dc3b162005-05-01 08:59:25 -0700363 <chapter id="devdrivers">
364 <title>Device drivers infrastructure</title>
365 <sect1><title>Device Drivers Base</title>
366<!--
367X!Iinclude/linux/device.h
368-->
369!Edrivers/base/driver.c
Pavel Pisa4dc3b162005-05-01 08:59:25 -0700370!Edrivers/base/core.c
Rolf Eike Beer78b22902006-09-29 01:59:12 -0700371!Edrivers/base/class.c
Pavel Pisa4dc3b162005-05-01 08:59:25 -0700372!Edrivers/base/firmware_class.c
373!Edrivers/base/transport_class.c
374!Edrivers/base/dmapool.c
375<!-- Cannot be included, because
376 attribute_container_add_class_device_adapter
377 and attribute_container_classdev_to_container
378 exceed allowed 44 characters maximum
379X!Edrivers/base/attribute_container.c
380-->
381!Edrivers/base/sys.c
382<!--
383X!Edrivers/base/interface.c
384-->
385!Edrivers/base/platform.c
386!Edrivers/base/bus.c
387 </sect1>
388 <sect1><title>Device Drivers Power Management</title>
Rob Landley3f51bed2007-10-16 23:31:31 -0700389!Edrivers/base/power/main.c
Pavel Pisa4dc3b162005-05-01 08:59:25 -0700390 </sect1>
391 <sect1><title>Device Drivers ACPI Support</title>
392<!-- Internal functions only
393X!Edrivers/acpi/sleep/main.c
394X!Edrivers/acpi/sleep/wakeup.c
395X!Edrivers/acpi/motherboard.c
396X!Edrivers/acpi/bus.c
397-->
398!Edrivers/acpi/scan.c
Randy Dunlapd758a8f2006-01-06 01:31:00 -0500399!Idrivers/acpi/scan.c
Pavel Pisa4dc3b162005-05-01 08:59:25 -0700400<!-- No correct structured comments
401X!Edrivers/acpi/pci_bind.c
402-->
403 </sect1>
404 <sect1><title>Device drivers PnP support</title>
Randy Dunlapb8a36792007-07-31 00:37:50 -0700405!Idrivers/pnp/core.c
Pavel Pisa4dc3b162005-05-01 08:59:25 -0700406<!-- No correct structured comments
407X!Edrivers/pnp/system.c
408 -->
409!Edrivers/pnp/card.c
Randy Dunlapb8a36792007-07-31 00:37:50 -0700410!Idrivers/pnp/driver.c
Pavel Pisa4dc3b162005-05-01 08:59:25 -0700411!Edrivers/pnp/manager.c
412!Edrivers/pnp/support.c
413 </sect1>
Hans J. Koche3e0a282006-12-11 16:59:59 +0100414 <sect1><title>Userspace IO devices</title>
415!Edrivers/uio/uio.c
416!Iinclude/linux/uio_driver.h
417 </sect1>
Pavel Pisa4dc3b162005-05-01 08:59:25 -0700418 </chapter>
419
Linus Torvalds1da177e2005-04-16 15:20:36 -0700420 <chapter id="blkdev">
421 <title>Block Devices</title>
Ben Collins1d193f42005-11-15 00:09:21 -0800422!Eblock/ll_rw_blk.c
Linus Torvalds1da177e2005-04-16 15:20:36 -0700423 </chapter>
424
Jonathan Corbetcf3e43d2006-09-29 02:00:44 -0700425 <chapter id="chrdev">
426 <title>Char devices</title>
427!Efs/char_dev.c
428 </chapter>
429
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430 <chapter id="miscdev">
431 <title>Miscellaneous Devices</title>
432!Edrivers/char/misc.c
433 </chapter>
434
Randy Dunlap7d469722006-06-25 05:49:29 -0700435 <chapter id="parportdev">
436 <title>Parallel Port Devices</title>
437!Iinclude/linux/parport.h
438!Edrivers/parport/ieee1284.c
439!Edrivers/parport/share.c
440!Idrivers/parport/daisy.c
441 </chapter>
442
Randy Dunlapda39aa82006-12-06 20:38:42 -0800443 <chapter id="message_devices">
444 <title>Message-based devices</title>
445 <sect1><title>Fusion message devices</title>
446!Edrivers/message/fusion/mptbase.c
447!Idrivers/message/fusion/mptbase.c
448!Edrivers/message/fusion/mptscsih.c
449!Idrivers/message/fusion/mptscsih.c
450!Idrivers/message/fusion/mptctl.c
451!Idrivers/message/fusion/mptspi.c
452!Idrivers/message/fusion/mptfc.c
453!Idrivers/message/fusion/mptlan.c
454 </sect1>
455 <sect1><title>I2O message devices</title>
456!Iinclude/linux/i2o.h
457!Idrivers/message/i2o/core.h
458!Edrivers/message/i2o/iop.c
459!Idrivers/message/i2o/iop.c
460!Idrivers/message/i2o/config-osm.c
461!Edrivers/message/i2o/exec-osm.c
462!Idrivers/message/i2o/exec-osm.c
463!Idrivers/message/i2o/bus-osm.c
464!Edrivers/message/i2o/device.c
465!Idrivers/message/i2o/device.c
466!Idrivers/message/i2o/driver.c
467!Idrivers/message/i2o/pci.c
468!Idrivers/message/i2o/i2o_block.c
469!Idrivers/message/i2o/i2o_scsi.c
470!Idrivers/message/i2o/i2o_proc.c
471 </sect1>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472 </chapter>
473
474 <chapter id="snddev">
475 <title>Sound Devices</title>
Pavel Pisa4dc3b162005-05-01 08:59:25 -0700476!Iinclude/sound/core.h
Linus Torvalds1da177e2005-04-16 15:20:36 -0700477!Esound/sound_core.c
Pavel Pisa4dc3b162005-05-01 08:59:25 -0700478!Iinclude/sound/pcm.h
479!Esound/core/pcm.c
480!Esound/core/device.c
481!Esound/core/info.c
482!Esound/core/rawmidi.c
483!Esound/core/sound.c
484!Esound/core/memory.c
485!Esound/core/pcm_memory.c
486!Esound/core/init.c
487!Esound/core/isadma.c
488!Esound/core/control.c
489!Esound/core/pcm_lib.c
490!Esound/core/hwdep.c
491!Esound/core/pcm_native.c
492!Esound/core/memalloc.c
Linus Torvalds1da177e2005-04-16 15:20:36 -0700493<!-- FIXME: Removed for now since no structured comments in source
494X!Isound/sound_firmware.c
495-->
496 </chapter>
497
498 <chapter id="uart16x50">
499 <title>16x50 UART Driver</title>
Pavel Pisa4dc3b162005-05-01 08:59:25 -0700500!Iinclude/linux/serial_core.h
Linus Torvalds1da177e2005-04-16 15:20:36 -0700501!Edrivers/serial/serial_core.c
502!Edrivers/serial/8250.c
503 </chapter>
504
505 <chapter id="z85230">
506 <title>Z85230 Support Library</title>
507!Edrivers/net/wan/z85230.c
508 </chapter>
509
510 <chapter id="fbdev">
511 <title>Frame Buffer Library</title>
512
513 <para>
514 The frame buffer drivers depend heavily on four data structures.
515 These structures are declared in include/linux/fb.h. They are
516 fb_info, fb_var_screeninfo, fb_fix_screeninfo and fb_monospecs.
517 The last three can be made available to and from userland.
518 </para>
519
520 <para>
521 fb_info defines the current state of a particular video card.
522 Inside fb_info, there exists a fb_ops structure which is a
523 collection of needed functions to make fbdev and fbcon work.
524 fb_info is only visible to the kernel.
525 </para>
526
527 <para>
528 fb_var_screeninfo is used to describe the features of a video card
529 that are user defined. With fb_var_screeninfo, things such as
530 depth and the resolution may be defined.
531 </para>
532
533 <para>
534 The next structure is fb_fix_screeninfo. This defines the
535 properties of a card that are created when a mode is set and can't
536 be changed otherwise. A good example of this is the start of the
537 frame buffer memory. This "locks" the address of the frame buffer
538 memory, so that it cannot be changed or moved.
539 </para>
540
541 <para>
542 The last structure is fb_monospecs. In the old API, there was
543 little importance for fb_monospecs. This allowed for forbidden things
544 such as setting a mode of 800x600 on a fix frequency monitor. With
545 the new API, fb_monospecs prevents such things, and if used
546 correctly, can prevent a monitor from being cooked. fb_monospecs
547 will not be useful until kernels 2.5.x.
548 </para>
549
550 <sect1><title>Frame Buffer Memory</title>
551!Edrivers/video/fbmem.c
552 </sect1>
Pavel Pisa4dc3b162005-05-01 08:59:25 -0700553<!--
Linus Torvalds1da177e2005-04-16 15:20:36 -0700554 <sect1><title>Frame Buffer Console</title>
Pavel Pisa4dc3b162005-05-01 08:59:25 -0700555X!Edrivers/video/console/fbcon.c
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556 </sect1>
Pavel Pisa4dc3b162005-05-01 08:59:25 -0700557-->
Linus Torvalds1da177e2005-04-16 15:20:36 -0700558 <sect1><title>Frame Buffer Colormap</title>
559!Edrivers/video/fbcmap.c
560 </sect1>
561<!-- FIXME:
562 drivers/video/fbgen.c has no docs, which stuffs up the sgml. Comment
563 out until somebody adds docs. KAO
564 <sect1><title>Frame Buffer Generic Functions</title>
565X!Idrivers/video/fbgen.c
566 </sect1>
567KAO -->
568 <sect1><title>Frame Buffer Video Mode Database</title>
569!Idrivers/video/modedb.c
570!Edrivers/video/modedb.c
571 </sect1>
572 <sect1><title>Frame Buffer Macintosh Video Mode Database</title>
Randy Dunlap8f2709b2005-11-07 01:01:05 -0800573!Edrivers/video/macmodes.c
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574 </sect1>
575 <sect1><title>Frame Buffer Fonts</title>
576 <para>
577 Refer to the file drivers/video/console/fonts.c for more information.
578 </para>
579<!-- FIXME: Removed for now since no structured comments in source
580X!Idrivers/video/console/fonts.c
581-->
582 </sect1>
583 </chapter>
Randy Dunlape4477d22006-11-24 00:43:09 -0500584
585 <chapter id="input_subsystem">
586 <title>Input Subsystem</title>
587!Iinclude/linux/input.h
588!Edrivers/input/input.c
589!Edrivers/input/ff-core.c
590!Edrivers/input/ff-memless.c
591 </chapter>
David Brownell33e34dc2007-05-08 00:32:21 -0700592
593 <chapter id="spi">
594 <title>Serial Peripheral Interface (SPI)</title>
595 <para>
596 SPI is the "Serial Peripheral Interface", widely used with
597 embedded systems because it is a simple and efficient
598 interface: basically a multiplexed shift register.
599 Its three signal wires hold a clock (SCK, often in the range
600 of 1-20 MHz), a "Master Out, Slave In" (MOSI) data line, and
601 a "Master In, Slave Out" (MISO) data line.
602 SPI is a full duplex protocol; for each bit shifted out the
603 MOSI line (one per clock) another is shifted in on the MISO line.
604 Those bits are assembled into words of various sizes on the
605 way to and from system memory.
606 An additional chipselect line is usually active-low (nCS);
607 four signals are normally used for each peripheral, plus
608 sometimes an interrupt.
609 </para>
610 <para>
611 The SPI bus facilities listed here provide a generalized
612 interface to declare SPI busses and devices, manage them
613 according to the standard Linux driver model, and perform
614 input/output operations.
615 At this time, only "master" side interfaces are supported,
616 where Linux talks to SPI peripherals and does not implement
617 such a peripheral itself.
618 (Interfaces to support implementing SPI slaves would
619 necessarily look different.)
620 </para>
621 <para>
622 The programming interface is structured around two kinds of driver,
623 and two kinds of device.
624 A "Controller Driver" abstracts the controller hardware, which may
625 be as simple as a set of GPIO pins or as complex as a pair of FIFOs
626 connected to dual DMA engines on the other side of the SPI shift
627 register (maximizing throughput). Such drivers bridge between
628 whatever bus they sit on (often the platform bus) and SPI, and
629 expose the SPI side of their device as a
630 <structname>struct spi_master</structname>.
631 SPI devices are children of that master, represented as a
632 <structname>struct spi_device</structname> and manufactured from
633 <structname>struct spi_board_info</structname> descriptors which
634 are usually provided by board-specific initialization code.
635 A <structname>struct spi_driver</structname> is called a
636 "Protocol Driver", and is bound to a spi_device using normal
637 driver model calls.
638 </para>
639 <para>
640 The I/O model is a set of queued messages. Protocol drivers
641 submit one or more <structname>struct spi_message</structname>
642 objects, which are processed and completed asynchronously.
643 (There are synchronous wrappers, however.) Messages are
644 built from one or more <structname>struct spi_transfer</structname>
645 objects, each of which wraps a full duplex SPI transfer.
646 A variety of protocol tweaking options are needed, because
647 different chips adopt very different policies for how they
648 use the bits transferred with SPI.
649 </para>
650!Iinclude/linux/spi/spi.h
651!Fdrivers/spi/spi.c spi_register_board_info
652!Edrivers/spi/spi.c
653 </chapter>
654
David Brownelld64f73b2007-07-12 14:12:28 +0200655 <chapter id="i2c">
656 <title>I<superscript>2</superscript>C and SMBus Subsystem</title>
657
658 <para>
659 I<superscript>2</superscript>C (or without fancy typography, "I2C")
660 is an acronym for the "Inter-IC" bus, a simple bus protocol which is
661 widely used where low data rate communications suffice.
662 Since it's also a licensed trademark, some vendors use another
663 name (such as "Two-Wire Interface", TWI) for the same bus.
664 I2C only needs two signals (SCL for clock, SDA for data), conserving
665 board real estate and minimizing signal quality issues.
666 Most I2C devices use seven bit addresses, and bus speeds of up
667 to 400 kHz; there's a high speed extension (3.4 MHz) that's not yet
668 found wide use.
669 I2C is a multi-master bus; open drain signaling is used to
670 arbitrate between masters, as well as to handshake and to
671 synchronize clocks from slower clients.
672 </para>
673
674 <para>
675 The Linux I2C programming interfaces support only the master
676 side of bus interactions, not the slave side.
677 The programming interface is structured around two kinds of driver,
678 and two kinds of device.
679 An I2C "Adapter Driver" abstracts the controller hardware; it binds
680 to a physical device (perhaps a PCI device or platform_device) and
681 exposes a <structname>struct i2c_adapter</structname> representing
682 each I2C bus segment it manages.
683 On each I2C bus segment will be I2C devices represented by a
684 <structname>struct i2c_client</structname>. Those devices will
685 be bound to a <structname>struct i2c_driver</structname>,
686 which should follow the standard Linux driver model.
687 (At this writing, a legacy model is more widely used.)
688 There are functions to perform various I2C protocol operations; at
689 this writing all such functions are usable only from task context.
690 </para>
691
692 <para>
693 The System Management Bus (SMBus) is a sibling protocol. Most SMBus
694 systems are also I2C conformant. The electrical constraints are
695 tighter for SMBus, and it standardizes particular protocol messages
696 and idioms. Controllers that support I2C can also support most
697 SMBus operations, but SMBus controllers don't support all the protocol
698 options that an I2C controller will.
699 There are functions to perform various SMBus protocol operations,
700 either using I2C primitives or by issuing SMBus commands to
701 i2c_adapter devices which don't support those I2C operations.
702 </para>
703
704!Iinclude/linux/i2c.h
705!Fdrivers/i2c/i2c-boardinfo.c i2c_register_board_info
706!Edrivers/i2c/i2c-core.c
707 </chapter>
708
Jens Axboe932cc6d2007-06-21 13:10:21 +0200709 <chapter id="splice">
710 <title>splice API</title>
Randy Dunlap79685b82007-07-27 08:08:51 +0200711 <para>
Jens Axboe932cc6d2007-06-21 13:10:21 +0200712 splice is a method for moving blocks of data around inside the
Randy Dunlap79685b82007-07-27 08:08:51 +0200713 kernel, without continually transferring them between the kernel
Jens Axboe932cc6d2007-06-21 13:10:21 +0200714 and user space.
715 </para>
Jens Axboe932cc6d2007-06-21 13:10:21 +0200716!Ffs/splice.c
717 </chapter>
718
Randy Dunlap79685b82007-07-27 08:08:51 +0200719 <chapter id="pipes">
720 <title>pipes API</title>
721 <para>
722 Pipe interfaces are all for in-kernel (builtin image) use.
723 They are not exported for use by modules.
724 </para>
725!Iinclude/linux/pipe_fs_i.h
726!Ffs/pipe.c
727 </chapter>
David Brownelld64f73b2007-07-12 14:12:28 +0200728
Linus Torvalds1da177e2005-04-16 15:20:36 -0700729</book>