|  | <?xml version="1.0" encoding="UTF-8"?> | 
|  | <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" | 
|  | "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> | 
|  |  | 
|  | <book id="LinuxKernelAPI"> | 
|  | <bookinfo> | 
|  | <title>The Linux Kernel API</title> | 
|  |  | 
|  | <legalnotice> | 
|  | <para> | 
|  | 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. | 
|  | </para> | 
|  |  | 
|  | <para> | 
|  | 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. | 
|  | </para> | 
|  |  | 
|  | <para> | 
|  | 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 | 
|  | </para> | 
|  |  | 
|  | <para> | 
|  | For more details see the file COPYING in the source | 
|  | distribution of Linux. | 
|  | </para> | 
|  | </legalnotice> | 
|  | </bookinfo> | 
|  |  | 
|  | <toc></toc> | 
|  |  | 
|  | <chapter id="adt"> | 
|  | <title>Data Types</title> | 
|  | <sect1><title>Doubly Linked Lists</title> | 
|  | !Iinclude/linux/list.h | 
|  | </sect1> | 
|  | </chapter> | 
|  |  | 
|  | <chapter id="libc"> | 
|  | <title>Basic C Library Functions</title> | 
|  |  | 
|  | <para> | 
|  | When writing drivers, you cannot in general use routines which are | 
|  | from the C Library.  Some of the functions have been found generally | 
|  | useful and they are listed below.  The behaviour of these functions | 
|  | may vary slightly from those defined by ANSI, and these deviations | 
|  | are noted in the text. | 
|  | </para> | 
|  |  | 
|  | <sect1><title>String Conversions</title> | 
|  | !Elib/vsprintf.c | 
|  | </sect1> | 
|  | <sect1><title>String Manipulation</title> | 
|  | <!-- All functions are exported at now | 
|  | X!Ilib/string.c | 
|  | --> | 
|  | !Elib/string.c | 
|  | </sect1> | 
|  | <sect1><title>Bit Operations</title> | 
|  | !Iarch/x86/include/asm/bitops.h | 
|  | </sect1> | 
|  | </chapter> | 
|  |  | 
|  | <chapter id="kernel-lib"> | 
|  | <title>Basic Kernel Library Functions</title> | 
|  |  | 
|  | <para> | 
|  | The Linux kernel provides more basic utility functions. | 
|  | </para> | 
|  |  | 
|  | <sect1><title>Bitmap Operations</title> | 
|  | !Elib/bitmap.c | 
|  | !Ilib/bitmap.c | 
|  | </sect1> | 
|  |  | 
|  | <sect1><title>Command-line Parsing</title> | 
|  | !Elib/cmdline.c | 
|  | </sect1> | 
|  |  | 
|  | <sect1 id="crc"><title>CRC Functions</title> | 
|  | !Elib/crc7.c | 
|  | !Elib/crc16.c | 
|  | !Elib/crc-itu-t.c | 
|  | !Elib/crc32.c | 
|  | !Elib/crc-ccitt.c | 
|  | </sect1> | 
|  |  | 
|  | <sect1 id="idr"><title>idr/ida Functions</title> | 
|  | !Pinclude/linux/idr.h idr sync | 
|  | !Plib/idr.c IDA description | 
|  | !Elib/idr.c | 
|  | </sect1> | 
|  | </chapter> | 
|  |  | 
|  | <chapter id="mm"> | 
|  | <title>Memory Management in Linux</title> | 
|  | <sect1><title>The Slab Cache</title> | 
|  | !Iinclude/linux/slab.h | 
|  | !Emm/slab.c | 
|  | </sect1> | 
|  | <sect1><title>User Space Memory Access</title> | 
|  | !Iarch/x86/include/asm/uaccess_32.h | 
|  | !Earch/x86/lib/usercopy_32.c | 
|  | </sect1> | 
|  | <sect1><title>More Memory Management Functions</title> | 
|  | !Emm/readahead.c | 
|  | !Emm/filemap.c | 
|  | !Emm/memory.c | 
|  | !Emm/vmalloc.c | 
|  | !Imm/page_alloc.c | 
|  | !Emm/mempool.c | 
|  | !Emm/dmapool.c | 
|  | !Emm/page-writeback.c | 
|  | !Emm/truncate.c | 
|  | </sect1> | 
|  | </chapter> | 
|  |  | 
|  |  | 
|  | <chapter id="ipc"> | 
|  | <title>Kernel IPC facilities</title> | 
|  |  | 
|  | <sect1><title>IPC utilities</title> | 
|  | !Iipc/util.c | 
|  | </sect1> | 
|  | </chapter> | 
|  |  | 
|  | <chapter id="kfifo"> | 
|  | <title>FIFO Buffer</title> | 
|  | <sect1><title>kfifo interface</title> | 
|  | !Iinclude/linux/kfifo.h | 
|  | </sect1> | 
|  | </chapter> | 
|  |  | 
|  | <chapter id="relayfs"> | 
|  | <title>relay interface support</title> | 
|  |  | 
|  | <para> | 
|  | Relay interface support | 
|  | is designed to provide an efficient mechanism for tools and | 
|  | facilities to relay large amounts of data from kernel space to | 
|  | user space. | 
|  | </para> | 
|  |  | 
|  | <sect1><title>relay interface</title> | 
|  | !Ekernel/relay.c | 
|  | !Ikernel/relay.c | 
|  | </sect1> | 
|  | </chapter> | 
|  |  | 
|  | <chapter id="modload"> | 
|  | <title>Module Support</title> | 
|  | <sect1><title>Module Loading</title> | 
|  | !Ekernel/kmod.c | 
|  | </sect1> | 
|  | <sect1><title>Inter Module support</title> | 
|  | <para> | 
|  | Refer to the file kernel/module.c for more information. | 
|  | </para> | 
|  | <!-- FIXME: Removed for now since no structured comments in source | 
|  | X!Ekernel/module.c | 
|  | --> | 
|  | </sect1> | 
|  | </chapter> | 
|  |  | 
|  | <chapter id="hardware"> | 
|  | <title>Hardware Interfaces</title> | 
|  | <sect1><title>Interrupt Handling</title> | 
|  | !Ekernel/irq/manage.c | 
|  | </sect1> | 
|  |  | 
|  | <sect1><title>DMA Channels</title> | 
|  | !Ekernel/dma.c | 
|  | </sect1> | 
|  |  | 
|  | <sect1><title>Resources Management</title> | 
|  | !Ikernel/resource.c | 
|  | !Ekernel/resource.c | 
|  | </sect1> | 
|  |  | 
|  | <sect1><title>MTRR Handling</title> | 
|  | !Earch/x86/kernel/cpu/mtrr/main.c | 
|  | </sect1> | 
|  |  | 
|  | <sect1><title>PCI Support Library</title> | 
|  | !Edrivers/pci/pci.c | 
|  | !Edrivers/pci/pci-driver.c | 
|  | !Edrivers/pci/remove.c | 
|  | !Edrivers/pci/search.c | 
|  | !Edrivers/pci/msi.c | 
|  | !Edrivers/pci/bus.c | 
|  | !Edrivers/pci/access.c | 
|  | !Edrivers/pci/irq.c | 
|  | !Edrivers/pci/htirq.c | 
|  | <!-- FIXME: Removed for now since no structured comments in source | 
|  | X!Edrivers/pci/hotplug.c | 
|  | --> | 
|  | !Edrivers/pci/probe.c | 
|  | !Edrivers/pci/slot.c | 
|  | !Edrivers/pci/rom.c | 
|  | !Edrivers/pci/iov.c | 
|  | !Idrivers/pci/pci-sysfs.c | 
|  | </sect1> | 
|  | <sect1><title>PCI Hotplug Support Library</title> | 
|  | !Edrivers/pci/hotplug/pci_hotplug_core.c | 
|  | </sect1> | 
|  | <sect1><title>MCA Architecture</title> | 
|  | <sect2><title>MCA Device Functions</title> | 
|  | <para> | 
|  | Refer to the file arch/x86/kernel/mca_32.c for more information. | 
|  | </para> | 
|  | <!-- FIXME: Removed for now since no structured comments in source | 
|  | X!Earch/x86/kernel/mca_32.c | 
|  | --> | 
|  | </sect2> | 
|  | <sect2><title>MCA Bus DMA</title> | 
|  | !Iarch/x86/include/asm/mca_dma.h | 
|  | </sect2> | 
|  | </sect1> | 
|  | </chapter> | 
|  |  | 
|  | <chapter id="firmware"> | 
|  | <title>Firmware Interfaces</title> | 
|  | <sect1><title>DMI Interfaces</title> | 
|  | !Edrivers/firmware/dmi_scan.c | 
|  | </sect1> | 
|  | <sect1><title>EDD Interfaces</title> | 
|  | !Idrivers/firmware/edd.c | 
|  | </sect1> | 
|  | </chapter> | 
|  |  | 
|  | <chapter id="security"> | 
|  | <title>Security Framework</title> | 
|  | !Isecurity/security.c | 
|  | !Esecurity/inode.c | 
|  | </chapter> | 
|  |  | 
|  | <chapter id="audit"> | 
|  | <title>Audit Interfaces</title> | 
|  | !Ekernel/audit.c | 
|  | !Ikernel/auditsc.c | 
|  | !Ikernel/auditfilter.c | 
|  | </chapter> | 
|  |  | 
|  | <chapter id="accounting"> | 
|  | <title>Accounting Framework</title> | 
|  | !Ikernel/acct.c | 
|  | </chapter> | 
|  |  | 
|  | <chapter id="blkdev"> | 
|  | <title>Block Devices</title> | 
|  | !Eblock/blk-core.c | 
|  | !Iblock/blk-core.c | 
|  | !Eblock/blk-map.c | 
|  | !Iblock/blk-sysfs.c | 
|  | !Eblock/blk-settings.c | 
|  | !Eblock/blk-exec.c | 
|  | !Eblock/blk-flush.c | 
|  | !Eblock/blk-lib.c | 
|  | !Eblock/blk-tag.c | 
|  | !Iblock/blk-tag.c | 
|  | !Eblock/blk-integrity.c | 
|  | !Ikernel/trace/blktrace.c | 
|  | !Iblock/genhd.c | 
|  | !Eblock/genhd.c | 
|  | </chapter> | 
|  |  | 
|  | <chapter id="chrdev"> | 
|  | <title>Char devices</title> | 
|  | !Efs/char_dev.c | 
|  | </chapter> | 
|  |  | 
|  | <chapter id="miscdev"> | 
|  | <title>Miscellaneous Devices</title> | 
|  | !Edrivers/char/misc.c | 
|  | </chapter> | 
|  |  | 
|  | <chapter id="clk"> | 
|  | <title>Clock Framework</title> | 
|  |  | 
|  | <para> | 
|  | The clock framework defines programming interfaces to support | 
|  | software management of the system clock tree. | 
|  | This framework is widely used with System-On-Chip (SOC) platforms | 
|  | to support power management and various devices which may need | 
|  | custom clock rates. | 
|  | Note that these "clocks" don't relate to timekeeping or real | 
|  | time clocks (RTCs), each of which have separate frameworks. | 
|  | These <structname>struct clk</structname> instances may be used | 
|  | to manage for example a 96 MHz signal that is used to shift bits | 
|  | into and out of peripherals or busses, or otherwise trigger | 
|  | synchronous state machine transitions in system hardware. | 
|  | </para> | 
|  |  | 
|  | <para> | 
|  | Power management is supported by explicit software clock gating: | 
|  | unused clocks are disabled, so the system doesn't waste power | 
|  | changing the state of transistors that aren't in active use. | 
|  | On some systems this may be backed by hardware clock gating, | 
|  | where clocks are gated without being disabled in software. | 
|  | Sections of chips that are powered but not clocked may be able | 
|  | to retain their last state. | 
|  | This low power state is often called a <emphasis>retention | 
|  | mode</emphasis>. | 
|  | This mode still incurs leakage currents, especially with finer | 
|  | circuit geometries, but for CMOS circuits power is mostly used | 
|  | by clocked state changes. | 
|  | </para> | 
|  |  | 
|  | <para> | 
|  | Power-aware drivers only enable their clocks when the device | 
|  | they manage is in active use.  Also, system sleep states often | 
|  | differ according to which clock domains are active:  while a | 
|  | "standby" state may allow wakeup from several active domains, a | 
|  | "mem" (suspend-to-RAM) state may require a more wholesale shutdown | 
|  | of clocks derived from higher speed PLLs and oscillators, limiting | 
|  | the number of possible wakeup event sources.  A driver's suspend | 
|  | method may need to be aware of system-specific clock constraints | 
|  | on the target sleep state. | 
|  | </para> | 
|  |  | 
|  | <para> | 
|  | Some platforms support programmable clock generators.  These | 
|  | can be used by external chips of various kinds, such as other | 
|  | CPUs, multimedia codecs, and devices with strict requirements | 
|  | for interface clocking. | 
|  | </para> | 
|  |  | 
|  | !Iinclude/linux/clk.h | 
|  | </chapter> | 
|  |  | 
|  | </book> |