Add uio_dmem_genirq description to UIO documentation

	</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">