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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="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="adt">
42     <title>Data Types</title>
43     <sect1><title>Doubly Linked Lists</title>
44!Iinclude/linux/list.h
45     </sect1>
46  </chapter>
47
48  <chapter id="libc">
49     <title>Basic C Library Functions</title>
50
51     <para>
52       When writing drivers, you cannot in general use routines which are
53       from the C Library.  Some of the functions have been found generally
54       useful and they are listed below.  The behaviour of these functions
55       may vary slightly from those defined by ANSI, and these deviations
56       are noted in the text.
57     </para>
58
59     <sect1><title>String Conversions</title>
60!Ilib/vsprintf.c
61!Elib/vsprintf.c
62     </sect1>
63     <sect1><title>String Manipulation</title>
64<!-- All functions are exported at now
65X!Ilib/string.c
66 -->
67!Elib/string.c
68     </sect1>
69     <sect1><title>Bit Operations</title>
70!Iarch/x86/include/asm/bitops.h
71     </sect1>
72  </chapter>
73
74  <chapter id="kernel-lib">
75     <title>Basic Kernel Library Functions</title>
76
77     <para>
78       The Linux kernel provides more basic utility functions.
79     </para>
80
81     <sect1><title>Bitmap Operations</title>
82!Elib/bitmap.c
83!Ilib/bitmap.c
84     </sect1>
85
86     <sect1><title>Command-line Parsing</title>
87!Elib/cmdline.c
88     </sect1>
89
90     <sect1 id="crc"><title>CRC Functions</title>
91!Elib/crc7.c
92!Elib/crc16.c
93!Elib/crc-itu-t.c
94!Elib/crc32.c
95!Elib/crc-ccitt.c
96     </sect1>
97  </chapter>
98
99  <chapter id="mm">
100     <title>Memory Management in Linux</title>
101     <sect1><title>The Slab Cache</title>
102!Iinclude/linux/slab.h
103!Emm/slab.c
104     </sect1>
105     <sect1><title>User Space Memory Access</title>
106!Iarch/x86/include/asm/uaccess_32.h
107!Earch/x86/lib/usercopy_32.c
108     </sect1>
109     <sect1><title>More Memory Management Functions</title>
110!Emm/readahead.c
111!Emm/filemap.c
112!Emm/memory.c
113!Emm/vmalloc.c
114!Imm/page_alloc.c
115!Emm/mempool.c
116!Emm/dmapool.c
117!Emm/page-writeback.c
118!Emm/truncate.c
119     </sect1>
120  </chapter>
121
122
123  <chapter id="ipc">
124     <title>Kernel IPC facilities</title>
125
126     <sect1><title>IPC utilities</title>
127!Iipc/util.c
128     </sect1>
129  </chapter>
130
131  <chapter id="kfifo">
132     <title>FIFO Buffer</title>
133     <sect1><title>kfifo interface</title>
134!Iinclude/linux/kfifo.h
135!Ekernel/kfifo.c
136     </sect1>
137  </chapter>
138
139  <chapter id="relayfs">
140     <title>relay interface support</title>
141
142     <para>
143	Relay interface support
144	is designed to provide an efficient mechanism for tools and
145	facilities to relay large amounts of data from kernel space to
146	user space.
147     </para>
148
149     <sect1><title>relay interface</title>
150!Ekernel/relay.c
151!Ikernel/relay.c
152     </sect1>
153  </chapter>
154
155  <chapter id="modload">
156     <title>Module Support</title>
157     <sect1><title>Module Loading</title>
158!Ekernel/kmod.c
159     </sect1>
160     <sect1><title>Inter Module support</title>
161        <para>
162           Refer to the file kernel/module.c for more information.
163        </para>
164<!-- FIXME: Removed for now since no structured comments in source
165X!Ekernel/module.c
166-->
167     </sect1>
168  </chapter>
169
170  <chapter id="hardware">
171     <title>Hardware Interfaces</title>
172     <sect1><title>Interrupt Handling</title>
173!Ekernel/irq/manage.c
174     </sect1>
175
176     <sect1><title>DMA Channels</title>
177!Ekernel/dma.c
178     </sect1>
179
180     <sect1><title>Resources Management</title>
181!Ikernel/resource.c
182!Ekernel/resource.c
183     </sect1>
184
185     <sect1><title>MTRR Handling</title>
186!Earch/x86/kernel/cpu/mtrr/main.c
187     </sect1>
188
189     <sect1><title>PCI Support Library</title>
190!Edrivers/pci/pci.c
191!Edrivers/pci/pci-driver.c
192!Edrivers/pci/remove.c
193!Edrivers/pci/pci-acpi.c
194!Edrivers/pci/search.c
195!Edrivers/pci/msi.c
196!Edrivers/pci/bus.c
197<!-- FIXME: Removed for now since no structured comments in source
198X!Edrivers/pci/hotplug.c
199-->
200!Edrivers/pci/probe.c
201!Edrivers/pci/rom.c
202     </sect1>
203     <sect1><title>PCI Hotplug Support Library</title>
204!Edrivers/pci/hotplug/pci_hotplug_core.c
205     </sect1>
206     <sect1><title>MCA Architecture</title>
207	<sect2><title>MCA Device Functions</title>
208           <para>
209              Refer to the file arch/x86/kernel/mca_32.c for more information.
210           </para>
211<!-- FIXME: Removed for now since no structured comments in source
212X!Earch/x86/kernel/mca_32.c
213-->
214	</sect2>
215	<sect2><title>MCA Bus DMA</title>
216!Iarch/x86/include/asm/mca_dma.h
217	</sect2>
218     </sect1>
219  </chapter>
220
221  <chapter id="firmware">
222     <title>Firmware Interfaces</title>
223     <sect1><title>DMI Interfaces</title>
224!Edrivers/firmware/dmi_scan.c
225     </sect1>
226     <sect1><title>EDD Interfaces</title>
227!Idrivers/firmware/edd.c
228     </sect1>
229  </chapter>
230
231  <chapter id="security">
232     <title>Security Framework</title>
233!Isecurity/security.c
234!Esecurity/inode.c
235  </chapter>
236
237  <chapter id="audit">
238     <title>Audit Interfaces</title>
239!Ekernel/audit.c
240!Ikernel/auditsc.c
241!Ikernel/auditfilter.c
242  </chapter>
243
244  <chapter id="accounting">
245     <title>Accounting Framework</title>
246!Ikernel/acct.c
247  </chapter>
248
249  <chapter id="blkdev">
250     <title>Block Devices</title>
251!Eblock/blk-core.c
252!Iblock/blk-core.c
253!Eblock/blk-map.c
254!Iblock/blk-sysfs.c
255!Eblock/blk-settings.c
256!Eblock/blk-exec.c
257!Eblock/blk-barrier.c
258!Eblock/blk-tag.c
259!Iblock/blk-tag.c
260!Eblock/blk-integrity.c
261!Iblock/blktrace.c
262!Iblock/genhd.c
263!Eblock/genhd.c
264  </chapter>
265
266  <chapter id="chrdev">
267	<title>Char devices</title>
268!Efs/char_dev.c
269  </chapter>
270
271  <chapter id="miscdev">
272     <title>Miscellaneous Devices</title>
273!Edrivers/char/misc.c
274  </chapter>
275
276  <chapter id="clk">
277     <title>Clock Framework</title>
278
279     <para>
280	The clock framework defines programming interfaces to support
281	software management of the system clock tree.
282	This framework is widely used with System-On-Chip (SOC) platforms
283	to support power management and various devices which may need
284	custom clock rates.
285	Note that these "clocks" don't relate to timekeeping or real
286	time clocks (RTCs), each of which have separate frameworks.
287	These <structname>struct clk</structname> instances may be used
288	to manage for example a 96 MHz signal that is used to shift bits
289	into and out of peripherals or busses, or otherwise trigger
290	synchronous state machine transitions in system hardware.
291     </para>
292
293     <para>
294	Power management is supported by explicit software clock gating:
295	unused clocks are disabled, so the system doesn't waste power
296	changing the state of transistors that aren't in active use.
297	On some systems this may be backed by hardware clock gating,
298	where clocks are gated without being disabled in software.
299	Sections of chips that are powered but not clocked may be able
300	to retain their last state.
301	This low power state is often called a <emphasis>retention
302	mode</emphasis>.
303	This mode still incurs leakage currents, especially with finer
304	circuit geometries, but for CMOS circuits power is mostly used
305	by clocked state changes.
306     </para>
307
308     <para>
309	Power-aware drivers only enable their clocks when the device
310	they manage is in active use.  Also, system sleep states often
311	differ according to which clock domains are active:  while a
312	"standby" state may allow wakeup from several active domains, a
313	"mem" (suspend-to-RAM) state may require a more wholesale shutdown
314	of clocks derived from higher speed PLLs and oscillators, limiting
315	the number of possible wakeup event sources.  A driver's suspend
316	method may need to be aware of system-specific clock constraints
317	on the target sleep state.
318     </para>
319
320     <para>
321        Some platforms support programmable clock generators.  These
322	can be used by external chips of various kinds, such as other
323	CPUs, multimedia codecs, and devices with strict requirements
324	for interface clocking.
325     </para>
326
327!Iinclude/linux/clk.h
328  </chapter>
329
330</book>
331