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author | Damian Hobson-Garcia <dhobsong@igel.co.jp> | 2012-09-25 08:09:12 +0200 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-10-25 00:39:09 +0200 |
commit | b533a83008c3fb4983c1213276790cacd39b518f (patch) | |
tree | bf127d1407e4982d3679ee3b6fb0815cb143cf77 /Documentation/DocBook/uio-howto.tmpl | |
parent | Add new uio device for dynamic memory allocation (diff) | |
download | linux-b533a83008c3fb4983c1213276790cacd39b518f.tar.xz linux-b533a83008c3fb4983c1213276790cacd39b518f.zip |
Add uio_dmem_genirq description to UIO documentation
Signed-off-by: Damian Hobson-Garcia <dhobsong@igel.co.jp>
Signed-off-by: "Hans J. Koch" <hjk@hansjkoch.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/DocBook/uio-howto.tmpl')
-rw-r--r-- | Documentation/DocBook/uio-howto.tmpl | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/Documentation/DocBook/uio-howto.tmpl b/Documentation/DocBook/uio-howto.tmpl index ac3d0018140c..fdbf86fcfccd 100644 --- a/Documentation/DocBook/uio-howto.tmpl +++ b/Documentation/DocBook/uio-howto.tmpl @@ -719,6 +719,62 @@ framework to set up sysfs files for this region. Simply leave it alone. </para> </sect1> +<sect1 id="using uio_dmem_genirq"> +<title>Using uio_dmem_genirq for platform devices</title> + <para> + In addition to statically allocated memory ranges, they may also be + a desire to use dynamically allocated regions in a user space driver. + In particular, being able to access memory made available through the + dma-mapping API, may be particularly useful. The + <varname>uio_dmem_genirq</varname> driver provides a way to accomplish + this. + </para> + <para> + This driver is used in a similar manner to the + <varname>"uio_pdrv_genirq"</varname> driver with respect to interrupt + configuration and handling. + </para> + <para> + Set the <varname>.name</varname> element of + <varname>struct platform_device</varname> to + <varname>"uio_dmem_genirq"</varname> to use this driver. + </para> + <para> + When using this driver, fill in the <varname>.platform_data</varname> + element of <varname>struct platform_device</varname>, which is of type + <varname>struct uio_dmem_genirq_pdata</varname> and which contains the + following elements: + </para> + <itemizedlist> + <listitem><varname>struct uio_info uioinfo</varname>: The same + structure used as the <varname>uio_pdrv_genirq</varname> platform + data</listitem> + <listitem><varname>unsigned int *dynamic_region_sizes</varname>: + Pointer to list of sizes of dynamic memory regions to be mapped into + user space. + </listitem> + <listitem><varname>unsigned int num_dynamic_regions</varname>: + Number of elements in <varname>dynamic_region_sizes</varname> array. + </listitem> + </itemizedlist> + <para> + The dynamic regions defined in the platform data will be appended to + the <varname> mem[] </varname> array after the platform device + resources, which implies that the total number of static and dynamic + memory regions cannot exceed <varname>MAX_UIO_MAPS</varname>. + </para> + <para> + The dynamic memory regions will be allocated when the UIO device file, + <varname>/dev/uioX</varname> is opened. + Simiar to static memory resources, the memory region information for + dynamic regions is then visible via sysfs at + <varname>/sys/class/uio/uioX/maps/mapY/*</varname>. + The dynmaic memory regions will be freed when the UIO device file is + closed. When no processes are holding the device file open, the address + returned to userspace is DMA_ERROR_CODE. + </para> +</sect1> + </chapter> <chapter id="userspace_driver" xreflabel="Writing a driver in user space"> |