On Tue, Sep 25, 2012 at 03:09:12PM +0900, Damian Hobson-Garcia wrote: > Signed-off-by: Damian Hobson-Garcia <dhobs...@igel.co.jp>
Signed-off-by: "Hans J. Koch" <h...@hansjkoch.de> > --- > 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 ac3d001..db08c1a 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"> > -- > 1.7.5.4 > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
