interrupts.html

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       *pEVT14 = evt_system_call;
       asm<span class="br0">&#40;</span><span class="st0">"csync;"</span><span class="br0">&#41;</span>;
       *pEVT15 = evt_soft_int1;
       asm<span class="br0">&#40;</span><span class="st0">"csync;"</span><span class="br0">&#41;</span>;
&nbsp;
       *pIMASK = <span class="nu0">0</span>;
       asm<span class="br0">&#40;</span><span class="st0">"csync;"</span><span class="br0">&#41;</span>;
       ilat  = *pILAT;
       asm<span class="br0">&#40;</span><span class="st0">"csync;"</span><span class="br0">&#41;</span>;
       *pILAT = ilat;
       asm<span class="br0">&#40;</span><span class="st0">"csync;"</span><span class="br0">&#41;</span>;
       printk<span class="br0">&#40;</span>KERN_INFO <span class="st0">"Configuring Blackfin Priority Driven Interrupts<span class="es0">\n</span>"</span><span class="br0">&#41;</span>;
       program_IAR<span class="br0">&#40;</span><span class="br0">&#41;</span>;   <span class="coMULTI">/* IMASK=xxx is equivalent to STI xx or irq_flags=xx,
                          local_irq_enable() */</span>                                           
       search_IAR<span class="br0">&#40;</span><span class="br0">&#41;</span>;    <span class="coMULTI">/* Therefore it's better to setup IARs before interrupts enabled */</span>                                                        
       <span class="coMULTI">/* Enable interrupts IVG7-15 */</span>
       *pIMASK = irq_flags = irq_flags | IMASK_IVG15 | IMASK_IVG14 |IMASK_IVG13
        |IMASK_IVG12 |IMASK_IVG11 | 
       IMASK_IVG10 |IMASK_IVG9 |IMASK_IVG8 |IMASK_IVG7 |IMASK_IVGHW;
          asm<span class="br0">&#40;</span><span class="st0">"csync;"</span><span class="br0">&#41;</span>;
       local_irq_enable<span class="br0">&#40;</span><span class="br0">&#41;</span>;
       <span class="kw1">return</span> <span class="nu0">0</span>;
  <span class="br0">&#125;</span></pre>
</div>
<!-- SECTION [8291-10095] -->
<h3><a name="blackfin_interrupt_service" id="blackfin_interrupt_service">Blackfin Interrupt Service</a></h3>
<div class="level3">

<p>
 This is from <strong>linux-2.6.x/arch/blackfin/mach-bf533/interrupt.S</strong> 
</p>
<pre class="code c">  <span class="coMULTI">/* interrupt routine for core timer - 6 */</span>    
  evt_timer:                                  
       SAVE_CONTEXT                               
       r0 = IRQ_CORETMR;                          
       r1 = sp;                                          
        SP += <span class="nu0">-12</span>;                                    
       call process_int;  <span class="coMULTI">/* call do_timer; */</span>    
        SP += <span class="nu0">12</span>;                                      
       RESTORE_CONTEXT                            
       rti;                                       
                                              
  <span class="coMULTI">/* interrupt routine for evt2 - 2 */</span>        
  evt_evt2:                                   
        SAVE_CONTEXT                              
        r0 = <span class="nu0">2</span>;                                   
        r1 =  sp;                                 
        SP += <span class="nu0">-12</span>;                                    
        call   process_int;                         
        SP += <span class="nu0">12</span>;                                      
        RESTORE_CONTEXT                           
&nbsp;
        rti;</pre>
</div>
<!-- SECTION [10096-11341] -->
<h2><a name="blackfin_system_timer" id="blackfin_system_timer">Blackfin System Timer</a></h2>
<div class="level2">

<p>
 The system timer is set up using an inline statement in the file  <strong>linux-2.6.x/arch/blackfin/mach-bf533/config.c</strong>
</p>
<pre class="code c">  <span class="co2">#include &lt;asm/machdep.h&gt;                                                   </span>
  <span class="co2">#include &lt;asm/blackfin.h&gt;                                                  </span>
                                                                             
  <span class="co2">#include &lt;asm/bf533_rtc.h&gt;                                                 </span>
                                                                             
                                                                             
  <span class="coMULTI">/*                                                                         
   * By setting TSCALE such that TCOUNT counts a binary fraction             
   * of microseconds, we can read TCOUNT directly and then with              
   * a logical shift trivially calculate how many microseconds               
   * since the last tick, allowing do_gettimeofday() to yield                
   * far better time resolution for real time benchmarking.                  
   */</span>                                                                        
                                                                             
                                                                             
  <span class="kw4">void</span> BSP_sched_init<span class="br0">&#40;</span>irqreturn_t<span class="br0">&#40;</span>*timer_routine<span class="br0">&#41;</span><span class="br0">&#40;</span><span class="kw4">int</span>, <span class="kw4">void</span> *, <span class="kw4">struct</span> pt_regs*<span class="br0">&#41;</span><span class="br0">&#41;</span>                                                                        
  <span class="br0">&#123;</span>                                                                          
         <span class="coMULTI">/* power up the timer, but don't enable it just yet */</span>              
          *pTCNTL = <span class="nu0">1</span>;                                                       
          asm<span class="br0">&#40;</span><span class="st0">"csync;"</span><span class="br0">&#41;</span>;                                                     
&nbsp;
          <span class="coMULTI">/* make TCOUNT a binary fraction of microseconds using             
           * the TSCALE prescaler counter                        */</span>          
          *pTSCALE = TSCALE_COUNT - <span class="nu0">1</span>;                                       
          asm<span class="br0">&#40;</span><span class="st0">"csync;"</span><span class="br0">&#41;</span>;                                                     
          *pTCOUNT = *pTPERIOD = CLOCKS_PER_JIFFY - <span class="nu0">1</span>;                       
          asm<span class="br0">&#40;</span><span class="st0">"csync;"</span><span class="br0">&#41;</span>;                                                     
&nbsp;
          <span class="coMULTI">/* now enable the timer */</span>                                         
          *pTCNTL = <span class="nu0">7</span>;                                                       
          asm<span class="br0">&#40;</span><span class="st0">"csync;"</span><span class="br0">&#41;</span>;                                                     
&nbsp;
          <span class="coMULTI">/* set up the timer irq  */</span>                                        
          request_irq<span class="br0">&#40;</span>IRQ_CORETMR, timer_routine, IRQ_FLG_LOCK, <span class="st0">"timer"</span>, <span class="kw2">NULL</span><span class="br0">&#41;</span>;
          enable_irq<span class="br0">&#40;</span>IRQ_CORETMR<span class="br0">&#41;</span>;                                           
                                                                             
  <span class="br0">&#125;</span></pre>
</div>
<!-- SECTION [11342-14321] -->
<h2><a name="linux_interrupt_overview" id="linux_interrupt_overview">Linux Interrupt Overview</a></h2>
<div class="level2">

<p>
 On the BF533 platforms the interrupt system uses a priority scheme to manage interrupts. A vector is provided for each priority.
</p>

<p>
The interrupt service routing has to monitor each interrupt associated with a given priority and detect the IRQ NUMBER for any given interrupt.
</p>

<p>
Once this number is detected the usual Linux interrupt handling can continue.
</p>

<p>
 The following files define and set up the interrupt system 
</p>
<ul>
<li class="level1"><div class="li"> linux-2.6.x/include/asm/irq.h</div>
</li>
<li class="level1"><div class="li"> linux-2.6.x/arch/blackfin/mach-bf533/ints-priority.c</div>
</li>
<li class="level1"><div class="li"> linux-2.6.x/arch/blackfin/mach-bf533/interrupt.S</div>
</li>
</ul>

<p>
 Here the priorities for each interrupt are set up
</p>
<pre class="code c">   <span class="co1">//extract from linux-2.6.x/arch/blackfin/mach-bf533/ints-priority.c    </span>
&nbsp;
          <span class="coMULTI">/* Program the IAR0 Register with the configured priority */</span>   
          *pSIC_IAR0 =  <span class="br0">&#40;</span><span class="br0">&#40;</span>CONFIG_PLLWAKE_ERROR<span class="nu0">-7</span><span class="br0">&#41;</span> &lt;&lt; PLLWAKE_ERROR_POS<span class="br0">&#41;</span> |
                  <span class="br0">&#40;</span><span class="br0">&#40;</span>CONFIG_DMA_ERROR   <span class="nu0">-7</span><span class="br0">&#41;</span> &lt;&lt;    DMA_ERROR_POS<span class="br0">&#41;</span> |        
                  <span class="br0">&#40;</span><span class="br0">&#40;</span>CONFIG_PPI_ERROR   <span class="nu0">-7</span><span class="br0">&#41;</span> &lt;&lt;    PPI_ERROR_POS<span class="br0">&#41;</span> |        
                  <span class="br0">&#40;</span><span class="br0">&#40;</span>CONFIG_SPORT0_ERROR<span class="nu0">-7</span><span class="br0">&#41;</span> &lt;&lt; SPORT0_ERROR_POS<span class="br0">&#41;</span> |        
                  <span class="br0">&#40;</span><span class="br0">&#40;</span>CONFIG_SPI_ERROR   <span class="nu0">-7</span><span class="br0">&#41;</span> &lt;&lt;    SPI_ERROR_POS<span class="br0">&#41;</span> |        
                  <span class="br0">&#40;</span><span class="br0">&#40;</span>CONFIG_SPORT1_ERROR<span class="nu0">-7</span><span class="br0">&#41;</span> &lt;&lt; SPORT1_ERROR_POS<span class="br0">&#41;</span> |        
                  <span class="br0">&#40;</span><span class="br0">&#40;</span>CONFIG_UART_ERROR  <span class="nu0">-7</span><span class="br0">&#41;</span> &lt;&lt;   UART_ERROR_POS<span class="br0">&#41;</span> |        
                  <span class="br0">&#40;</span><span class="br0">&#40;</span>CONFIG_RTC_ERROR   <span class="nu0">-7</span><span class="br0">&#41;</span> &lt;&lt;    RTC_ERROR_POS<span class="br0">&#41;</span>;         
                  asm<span class="br0">&#40;</span><span class="st0">"ssync;"</span><span class="br0">&#41;</span>;                                         
&nbsp;
           *pSIC_IAR1 =    <span class="br0">&#40;</span><span class="br0">&#40;</span>CONFIG_DMA0_PPI<span class="nu0">-7</span><span class="br0">&#41;</span> &lt;&lt;     DMA0_PPI_POS<span class="br0">&#41;</span> |   
                  <span class="br0">&#40;</span><span class="br0">&#40;</span>CONFIG_DMA1_SPORT0RX<span class="nu0">-7</span><span class="br0">&#41;</span> &lt;&lt; DMA1_SPORT0RX_POS<span class="br0">&#41;</span> |      
                  <span class="br0">&#40;</span><span class="br0">&#40;</span>CONFIG_DMA2_SPORT0TX<span class="nu0">-7</span><span class="br0">&#41;</span> &lt;&lt; DMA2_SPORT0TX_POS<span class="br0">&#41;</span> |      
                  <span class="br0">&#40;</span><span class="br0">&#40;</span>CONFIG_DMA3_SPORT1RX<span class="nu0">-7</span><span class="br0">&#41;</span> &lt;&lt; DMA3_SPORT1RX_POS<span class="br0">&#41;</span> |      
                  <span class="br0">&#40;</span><span class="br0">&#40;</span>CONFIG_DMA4_SPORT1TX<span class="nu0">-7</span><span class="br0">&#41;</span> &lt;&lt; DMA4_SPORT1TX_POS<span class="br0">&#41;</span> |      
                  <span class="br0">&#40;</span><span class="br0">&#40;</span>CONFIG_DMA5_SPI<span class="nu0">-7</span><span class="br0">&#41;</span>    &lt;&lt; DMA5_SPI_POS<span class="br0">&#41;</span>    |          
                  <span class="br0">&#40;</span><span class="br0">&#40;</span>CONFIG_DMA6_UARTRX<span class="nu0">-7</span><span class="br0">&#41;</span> &lt;&lt; DMA6_UARTRX_POS<span class="br0">&#41;</span> |          
                  <span class="br0">&#40;</span><span class="br0">&#40;</span>CONFIG_DMA7_UARTTX<span class="nu0">-7</span><span class="br0">&#41;</span> &lt;&lt; DMA7_UARTTX_POS<span class="br0">&#41;</span>;           
                  asm<span class="br0">&#40;</span><span class="st0">"ssync;"</span><span class="br0">&#41;</span>;                                         
&nbsp;
           *pSIC_IAR2 =    <span class="br0">&#40;</span><span class="br0">&#40;</span>CONFIG_TIMER0<span class="nu0">-7</span><span class="br0">&#41;</span> &lt;&lt; TIMER0_POS<span class="br0">&#41;</span> |           
                  <span class="br0">&#40;</span><span class="br0">&#40;</span>CONFIG_TIMER1<span class="nu0">-7</span><span class="br0">&#41;</span> &lt;&lt; TIMER1_POS<span class="br0">&#41;</span> |                    
                  <span class="br0">&#40;</span><span class="br0">&#40;</span>CONFIG_TIMER2<span class="nu0">-7</span><span class="br0">&#41;</span> &lt;&lt; TIMER2_POS<span class="br0">&#41;</span> |                    
                  <span class="br0">&#40;</span><span class="br0">&#40;</span>CONFIG_PFA<span class="nu0">-7</span><span class="br0">&#41;</span> &lt;&lt; PFA_POS<span class="br0">&#41;</span> |                          
                  <span class="br0">&#40;</span><span class="br0">&#40;</span>CONFIG_PFB<span class="nu0">-7</span><span class="br0">&#41;</span> &lt;&lt; PFB_POS<span class="br0">&#41;</span> |                          
                  <span class="br0">&#40;</span><span class="br0">&#40;</span>CONFIG_MEMDMA0<span class="nu0">-7</span><span class="br0">&#41;</span> &lt;&lt; MEMDMA0_POS<span class="br0">&#41;</span> |                  
                  <span class="br0">&#40;</span><span class="br0">&#40;</span>CONFIG_MEMDMA1<span class="nu0">-7</span><span class="br0">&#41;</span> &lt;&lt; MEMDMA1_POS<span class="br0">&#41;</span> |                  
                  <span class="br0">&#40;</span><span class="br0">&#40;</span>CONFIG_WDTIMER<span class="nu0">-7</span><span class="br0">&#41;</span> &lt;&lt; WDTIMER_POS<span class="br0">&#41;</span>; 
                  asm<span class="br0">&#40;</span><span class="st0">"ssync;"</span><span class="br0">&#41;</span>;                                         
<span class="br0">&#125;</span></pre>
<p>
                                                                          The actual interrupt service routines are here
</p>
<pre class="code c">  <span class="co1">// extract from linux-2.6.x/arch/blackfin/mach-bf533/interrupts.S</span>
                                                                  
  <span class="coMULTI">/* interrupt routine for core timer - 6 */</span>                      
  evt_timer:                                                      
          SAVE_CONTEXT                                            
          r0 = IRQ_CORETMR;                                       
          r1 = sp;                                                
           SP += <span class="nu0">-12</span>;                                             
          call process_int;  <span class="coMULTI">/* call do_timer; */</span>                 
           SP += <span class="nu0">12</span>;                                              
          RESTORE_CONTEXT                                         
          rti;                                                    
                                                                  
  <span class="coMULTI">/* interrupt routine for evt12  - 12 */</span>                         
  evt_evt12:                                                      
           SAVE_CONTEXT                                           
           r0 = <span class="nu0">12</span>;