Re: [v2 PATCH 2/2] Add uio_dmem_genirq description to UIOdocumentation

From: Hans J. Koch
Date: Wed Sep 26 2012 - 19:41:29 EST


On Tue, Sep 25, 2012 at 03:09:12PM +0900, Damian Hobson-Garcia wrote:
> Signed-off-by: Damian Hobson-Garcia <dhobsong@xxxxxxxxxx>

Signed-off-by: "Hans J. Koch" <hjk@xxxxxxxxxxxx>

> ---
> 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 majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/