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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-423537D5-2C8A-5C26-8D7B-60446E95F681" xml:lang="en"><title>Interrupt |
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13 Layer Initialisation</title><shortdesc>This topic describes how to implement the <codeph>Asic::Init1()</codeph> and <codeph>Asic::Init3()</codeph> functions |
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14 to initialise interrupts. </shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody> |
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15 <section id="GUID-78C26133-367A-44B4-832F-52299F1639BC"><title>In first phase |
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16 initialisation</title> <p>During first phase initialisation of start-up, the |
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17 kernel calls the ASSP's implementation of <xref href="GUID-A83A7C3C-7DC0-3B9C-842F-70FCC751365D.dita#GUID-A83A7C3C-7DC0-3B9C-842F-70FCC751365D/GUID-63F2135B-4264-3B3B-9B68-656A89BF7EE9"><apiname>Asic::Init1()</apiname></xref>. |
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18 For the template reference board, where the ASSP is split into a common, ASSP |
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19 layer and a device-specific (variant) layer, interrupt handling is initialised |
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20 in the ASSP layer, specifically in <codeph>TemplateAssp::Init1()</codeph>, |
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21 defined in <filepath>...\template_assp\template_assp_priv.h</filepath>, and |
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22 implemented in <filepath> ...\template_assp\assp.cpp</filepath>. </p> <p>Note |
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23 that interrupts are <i>disabled</i> during first phase initialisation. </p> <p>Within |
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24 your implementation of <codeph>Init1()</codeph>, do the following: </p> <ul> |
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25 <li id="GUID-21B39DCF-EFF2-56EE-921C-600BAF6DEF2B"><p>Initialise <xref href="GUID-76A30EC4-4B99-5471-9E80-F853C91485BC.dita#GUID-76A30EC4-4B99-5471-9E80-F853C91485BC/GUID-77E83634-BBF6-5190-9434-9FB700547CD0">the ISR table</xref>. </p> <p>It is useful to initialise the ISR table so |
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26 that each interrupt is bound, by default, to the <xref href="GUID-76A30EC4-4B99-5471-9E80-F853C91485BC.dita#GUID-76A30EC4-4B99-5471-9E80-F853C91485BC/GUID-9D98586F-AD1D-5C50-9AD8-F81D72135382">Spurious interrupts</xref> handler, with the 32-bit parameter taking the |
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27 interrupt number. </p> <p>For example, </p> <codeblock id="GUID-9CCBD3F2-49EE-53CF-92D1-30AE7266EB16" xml:space="preserve">... |
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28 const TInt KInterruptSourceCount = 32; |
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29 SInterruptHandler IsrHandlers[KInterruptSourceCount]; |
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30 ... |
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31 |
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32 for( TInt i = 0; i < KInterruptSourceCount; ++i ) |
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33 { |
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34 IsrHandlers[i].iIsr = SpuriousHandler; |
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35 IsrHandlers[i].iPtr = (TAny*)i; |
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36 }</codeblock> <p>where the spurious interrupt handler function might be |
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37 implemented as: </p> <codeblock id="GUID-F9ED35A6-2473-5B8C-B8C8-D8EB75463192" xml:space="preserve">void SpuriousHandler(TAny* aId) |
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38 { |
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39 Kern::Fault("SpuriousInt", (TInt)aId); // handle unexpected interrupt. |
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40 } |
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41 </codeblock> <p>On the template reference board, the ISR table is initialised |
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42 by <codeph>TemplateInterrupt::Init1()</codeph> in <filepath>...\template_assp\interrupts.cpp</filepath>, |
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43 and this is called by <codeph>TemplateAssp::Init1()</codeph>. </p> </li> |
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44 <li id="GUID-FBC1F518-7CC8-54FD-AD13-1C74C1C1E414"><p>Register the dispatcher |
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45 functions. The Symbian platform kernel needs to know the location of the IRQ |
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46 and FIQ dispatchers. It provides the two functions: <xref href="GUID-2A4186A4-DCE1-3726-9D6A-BBA2604FAAF5.dita#GUID-2A4186A4-DCE1-3726-9D6A-BBA2604FAAF5/GUID-7C0DD618-1FA4-39CD-BEE0-E7F5ED018C9C"><apiname>Arm::SetIrqHandler()</apiname></xref> and <xref href="GUID-2A4186A4-DCE1-3726-9D6A-BBA2604FAAF5.dita#GUID-2A4186A4-DCE1-3726-9D6A-BBA2604FAAF5/GUID-390FDCB3-53E7-303C-B6D7-CFBA214E8135"><apiname>Arm::SetFiqHandler()</apiname></xref>, |
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47 which the Variant layer must call, passing the addresses of the IRQ and FIQ |
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48 dispatchers. </p> <p>On the template reference board, the registration is |
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49 done by <codeph>TemplateInterrupt::Init1()</codeph> in <filepath>...\template_assp\interrupts.cpp</filepath>. </p> <codeblock id="GUID-6A634065-4C51-5A84-9AF6-82654B7D54C6" xml:space="preserve">void TemplateInterrupt::Init1() |
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50 { |
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51 // |
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52 // need to hook the ARM IRQ and FIQ handlers as early as possible |
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53 // and disable and clear all interrupt sources |
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54 // |
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55 ... |
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56 DisableAndClearAll(); |
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57 Arm::SetIrqHandler((TLinAddr)TemplateInterrupt::IrqDispatch); |
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58 Arm::SetFiqHandler((TLinAddr)TemplateInterrupt::FiqDispatch); |
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59 } |
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60 </codeblock> </li> |
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61 <li id="GUID-F4D217AF-8B8D-56AB-8D09-2E70566FE5D2"><p>Bind any ISRs that handle |
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62 chained or pseudo interrupts </p> </li> |
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63 </ul> </section> |
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64 <section id="GUID-7D6DACC3-FAD7-49C8-98DE-1024518E49AF"><title>In third phase |
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65 initialisation</title> <p>During third phase initialisation of start-up, the |
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66 kernel calls the ASSP's implementation of <xref href="GUID-A83A7C3C-7DC0-3B9C-842F-70FCC751365D.dita#GUID-A83A7C3C-7DC0-3B9C-842F-70FCC751365D/GUID-FE55E398-7F08-384F-9E74-2CC2E45002B6"><apiname>Asic::Init3()</apiname></xref>. </p> <p>Note |
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67 that interrupts are <i>enabled</i> during third phase initialisation. </p> <p>Within |
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68 your implementation of <codeph>Init3()</codeph>, if you need to, call <xref href="GUID-E7A7083C-97B9-39B9-A147-4A6E314EE3A3.dita#GUID-E7A7083C-97B9-39B9-A147-4A6E314EE3A3/GUID-BB169E6E-D8F9-3762-899D-6DBA4B29CF87"><apiname>Interrupt::Enable()</apiname></xref> on |
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69 any of the interrupt sources that are bound to a chained or pseudo ISR dispatcher. |
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70 You don't need to do this if you are enabling and disabling the main interrupt |
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71 on demand as the chained or pseudo-interrupts are enabled and disabled. </p> </section> |
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72 </conbody></concept> |