title: Linux kernel: CMA & Device Tree
body: <p>I've tried to use the CMA (Contiguous Memory Allocator) configured with DT. But how can I access the allocated memory region form the module?</p>
  
  <p>This is the DT part:</p>
  
  <pre><code>reserved-memory {
      #address-cells = &lt;1&gt;;
      #size-cells = &lt;1&gt;;
      ranges;
  
      dsp_reserved: dsp@83400000 {
          reg = &lt;0x83400000 0x400000&gt;;
          no-map;
      };
  };
  
  c64_dsp {
      compatible = "c64-dsp";
      interrupt-parent = &lt;&amp;intc&gt;;
      interrupts = &lt;26&gt;;
      memory-region = &lt;&amp;dsp_reserved&gt;;
  };
  </code></pre>
  
  <p>How can I get the reserved memory region "dsp_reserved" in my own driver? Is this region already requested by "dma_alloc_coherent"? Is there a function similar to "platform_get_irq"?</p>
  
  <p>Thanks for help,
  Sven</p>