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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>dma_pool_create</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /><link rel="home" href="index.html" title="The Linux Kernel API" /><link rel="up" href="ch04s03.html" title="More Memory Management Functions" /><link rel="prev" href="re217.html" title="mempool_free" /><link rel="next" href="re219.html" title="dma_pool_destroy" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center"><span>dma_pool_create</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="re217.html">Prev</a> </td><th width="60%" align="center">More Memory Management Functions</th><td width="20%" align="right"> <a accesskey="n" href="re219.html">Next</a></td></tr></table><hr /></div><div class="refentry" title="dma_pool_create"><a id="API-dma-pool-create"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>dma_pool_create —
Creates a pool of consistent memory blocks, for dma.
</p></div><div class="refsynopsisdiv" title="Synopsis"><h2>Synopsis</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">struct dma_pool * <b class="fsfunc">dma_pool_create </b>(</code></td><td>const char * <var class="pdparam">name</var>, </td></tr><tr><td> </td><td>struct device * <var class="pdparam">dev</var>, </td></tr><tr><td> </td><td>size_t <var class="pdparam">size</var>, </td></tr><tr><td> </td><td>size_t <var class="pdparam">align</var>, </td></tr><tr><td> </td><td>size_t <var class="pdparam">boundary</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1" title="Arguments"><a id="id2983807"></a><h2>Arguments</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>name</code></em></span></dt><dd><p>
name of pool, for diagnostics
</p></dd><dt><span class="term"><em class="parameter"><code>dev</code></em></span></dt><dd><p>
device that will be doing the DMA
</p></dd><dt><span class="term"><em class="parameter"><code>size</code></em></span></dt><dd><p>
size of the blocks in this pool.
</p></dd><dt><span class="term"><em class="parameter"><code>align</code></em></span></dt><dd><p>
alignment requirement for blocks; must be a power of two
</p></dd><dt><span class="term"><em class="parameter"><code>boundary</code></em></span></dt><dd><p>
returned blocks won't cross this power of two boundary
</p></dd></dl></div></div><div class="refsect1" title="Context"><a id="id2983903"></a><h2>Context</h2><p>
!<code class="function">in_interrupt</code>
</p></div><div class="refsect1" title="Description"><a id="id2983919"></a><h2>Description</h2><p>
Returns a dma allocation pool with the requested characteristics, or
null if one can't be created. Given one of these pools, <code class="function">dma_pool_alloc</code>
may be used to allocate memory. Such memory will all have <span class="quote">“<span class="quote">consistent</span>”</span>
DMA mappings, accessible by the device and its driver without using
cache flushing primitives. The actual size of blocks allocated may be
larger than requested because of alignment.
</p><p>
If <em class="parameter"><code>boundary</code></em> is nonzero, objects returned from <code class="function">dma_pool_alloc</code> won't
cross that size boundary. This is useful for devices which have
addressing restrictions on individual DMA transfers, such as not crossing
boundaries of 4KBytes.
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