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1 <?xml version="1.0" encoding="utf-8"?> |
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2 <!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. --> |
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3 <!-- This component and the accompanying materials are made available under the terms of the License |
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4 "Eclipse Public License v1.0" which accompanies this distribution, |
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5 and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". --> |
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6 <!-- Initial Contributors: |
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7 Nokia Corporation - initial contribution. |
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8 Contributors: |
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9 --> |
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10 <!DOCTYPE concept |
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11 PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd"> |
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12 <concept id="GUID-092D336A-155A-4F18-AAF7-92E08473700E" xml:lang="en"><title>DMA Overview</title><shortdesc>Direct Memory Access (DMA) uses a controller to copy data |
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13 between memory locations, or between memory and peripherals with minimal |
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14 involvement from the CPU.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody> |
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15 <section id="GUID-04298BEC-F064-40C4-9A8C-DFB15953C85B"><title>Purpose</title><p>Direct Memory Access (DMA) channels allow you to copy data between |
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16 memory locations, or between memory and peripherals, while minimizing |
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17 the use of the CPU. The transfer operation is performed in hardware |
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18 by the DMA controller. The purpose of the DMA platform service is |
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19 to provide a common interface between hardware and device drivers |
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20 which use DMA.</p><p>The framework is divided into a platform-independent |
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21 layer and a platform-specific layer, with the DMA platform service |
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22 being the interface between the two. The framework presents an API |
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23 for use by device drivers and other client applications which transfer |
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24 data by DMA. The PSL must be implemented by hardware developers to |
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25 provide the same functionality on multiple platforms.</p></section> |
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26 <section id="GUID-140D36E7-EFC1-4206-A563-417AAB6BCC1C"><title>Architecture</title><p><fig id="GUID-0EF82751-1A74-4A39-BA92-E7E8F441E7F7"> |
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27 <title>DMA Framework</title> |
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28 <image href="GUID-A6845EB0-4B4D-49C8-85A5-A933A2C351CF_d0e89230_href.png" placement="inline"/> |
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29 </fig></p></section> |
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30 </conbody></concept> |