diff -r 89d6a7a84779 -r 25a17d01db0c Symbian3/PDK/Source/GUID-D2163920-D448-5BFC-B655-B654FD657A94.dita
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Symbian3/PDK/Source/GUID-D2163920-D448-5BFC-B655-B654FD657A94.dita	Fri Jan 22 18:26:19 2010 +0000
@@ -0,0 +1,35 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->
+<!-- This component and the accompanying materials are made available under the terms of the License 
+"Eclipse Public License v1.0" which accompanies this distribution, 
+and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->
+<!-- Initial Contributors:
+    Nokia Corporation - initial contribution.
+Contributors: 
+-->
+<!DOCTYPE concept
+  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
+<concept id="GUID-D2163920-D448-5BFC-B655-B654FD657A94" xml:lang="en"><title>Level
+2 Cache</title><shortdesc>Level 2 cache is cache memory that is external to the microprocessor.
+The kernel provides functions to perform operations on this cache. </shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
+<p>In general, the presence of Level 2 cache is transparent to device drivers.
+The cache is physically indexed and physically tagged, and this means that
+L2 cache is not affected by the remapping of virtual-to-physical addresses
+in the MMU. </p>
+<p>However, where data is being transferred using DMA, then cached information
+in the data buffers involved in a DMA transfer must be flushed before a DMA
+write operation, for example when transferring data from memory to a peripheral,
+and both before and after a DMA read operation, for example when transferring
+data from a peripheral into memory. </p>
+<p>The kernel provides three functions for this: </p>
+<ul>
+<li id="GUID-031134D4-1CF6-503F-9DBD-75836242A0BD"><p> <xref href="GUID-4425E698-EE8A-369B-92CD-09B1CBD2911F.dita#GUID-4425E698-EE8A-369B-92CD-09B1CBD2911F/GUID-5F08DEAA-1237-32DE-AE41-CE7B18230972"><apiname>Cache::SyncMemoryBeforeDmaWrite()</apiname></xref>  </p> </li>
+<li id="GUID-0E0BBB26-1F1C-5A64-A9D3-506B5D6783EA"><p> <xref href="GUID-4425E698-EE8A-369B-92CD-09B1CBD2911F.dita#GUID-4425E698-EE8A-369B-92CD-09B1CBD2911F/GUID-3FF3C567-C1BD-3D4E-97E1-B036456A374E"><apiname> Cache::SyncMemoryBeforeDmaRead()</apiname></xref>  </p> </li>
+<li id="GUID-DB3947C1-1BB7-5678-A337-48C74B903496"><p> <xref href="GUID-4425E698-EE8A-369B-92CD-09B1CBD2911F.dita#GUID-4425E698-EE8A-369B-92CD-09B1CBD2911F/GUID-78E6DE46-61F0-3840-B555-6926D21141BF"><apiname> Cache::SyncMemoryAfterDmaRead()</apiname></xref>  </p> </li>
+</ul>
+<p>All three functions are defined and implemented as part of the <xref href="GUID-4425E698-EE8A-369B-92CD-09B1CBD2911F.dita"><apiname>Cache</apiname></xref> class,
+defined in <filepath>...\e32\e32\include\kernel\cache.h.</filepath>  </p>
+<p>See also <xref href="GUID-18EFC99D-68B6-51E1-8520-272DC278E82A.dita#GUID-18EFC99D-68B6-51E1-8520-272DC278E82A/GUID-F9DA4E5B-5675-55D3-9793-0D8404FAA7B6"> DMA
+buffers</xref> in the <xref href="GUID-18EFC99D-68B6-51E1-8520-272DC278E82A.dita">Device
+Driver Tutorial</xref>. </p>
+</conbody></concept>
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