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<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968" /><title>Some Hafta's</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /><link rel="home" href="index.html" title="Writing an ALSA Driver" /><link rel="up" href="ch04.html" title="Chapter 4. PCI Resource Management" /><link rel="prev" href="ch04.html" title="Chapter 4. PCI Resource Management" /><link rel="next" href="ch04s03.html" title="Resource Allocation" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Some Hafta's</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ch04.html">Prev</a> </td><th width="60%" align="center">Chapter 4. PCI Resource Management</th><td width="20%" align="right"> <a accesskey="n" href="ch04s03.html">Next</a></td></tr></table><hr /></div><div class="section" title="Some Hafta's"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="pci-resource-some-haftas"></a>Some Hafta's</h2></div></div></div><p>
The allocation of PCI resources is done in the
<code class="function">probe()</code> function, and usually an extra
<code class="function">xxx_create()</code> function is written for this
purpose.
</p><p>
In the case of PCI devices, you first have to call
the <code class="function">pci_enable_device()</code> function before
allocating resources. Also, you need to set the proper PCI DMA
mask to limit the accessed I/O range. In some cases, you might
need to call <code class="function">pci_set_master()</code> function,
too.
</p><p>
Suppose the 28bit mask, and the code to be added would be like:
</p><div class="informalexample"><pre class="programlisting">
err = pci_enable_device(pci);
if (err < 0)
return err;
if (pci_set_dma_mask(pci, DMA_BIT_MASK(28)) < 0 ||
pci_set_consistent_dma_mask(pci, DMA_BIT_MASK(28)) < 0) {
printk(KERN_ERR "error to set 28bit mask DMA\n");
pci_disable_device(pci);
return -ENXIO;
}
</pre></div><p>
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