| From dhobsong@igel.co.jp Wed Nov 21 18:27:15 2012 |
| From: Damian Hobson-Garcia <dhobsong@igel.co.jp> |
| Date: Thu, 22 Nov 2012 11:26:49 +0900 |
| Subject: [PATCH 2/6] drivers: uio: Add uio_dmem_genirq description to UIO documentation |
| To: gregkh@linuxfoundation.org |
| Cc: ltsi-dev@lists.linuxfoundation.org, Damian Hobson-Garcia <dhobsong@igel.co.jp> |
| Message-ID: <1353551213-17996-3-git-send-email-dhobsong@igel.co.jp> |
| |
| |
| Signed-off-by: Damian Hobson-Garcia <dhobsong@igel.co.jp> |
| --- |
| Documentation/DocBook/uio-howto.tmpl | 56 +++++++++++++++++++++++++++++++++++ |
| 1 file changed, 56 insertions(+) |
| |
| --- a/Documentation/DocBook/uio-howto.tmpl |
| +++ b/Documentation/DocBook/uio-howto.tmpl |
| @@ -719,6 +719,62 @@ framework to set up sysfs files for this |
| </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"> |