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authorLinus Torvalds <torvalds@linux-foundation.org>2012-12-11 13:56:38 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2012-12-11 13:56:38 -0800
commit6a5971d8fea1f4a8c33dfe0cec6a1c490f0c9cde (patch)
tree982911522177da03dd839d816a6a93cc210e4657 /Documentation/DocBook/uio-howto.tmpl
parentcff2f741b8ee8a70b208830e330de053efd4fc45 (diff)
parent70e78c40ed6c25bb34d642848e485d79ffc55c26 (diff)
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Merge tag 'char-misc-3.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
Pull Char/Misc driver merge from Greg Kroah-Hartman: "Here is the "big" char/misc driver patches for 3.8-rc1. I'm starting to put random driver subsystems that I had previously sent you through the driver-core tree in this tree, as it makes more sense to do so. Nothing major here, the various __dev* removals, some mei driver updates, and other random driver-specific things from the different maintainers and developers. Note, some MFD drivers got added through this tree, and they are also coming in through the "real" MFD tree as well, due to some major mis-communication between me and the different developers. If you have any merge conflicts, take the ones from the MFD tree, not these ones, sorry about that. All of this has been in linux-next for a while. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>" Fix up trivial conflict in drivers/mmc/host/Kconfig due to new drivers having been added (both at the end, as usual..) * tag 'char-misc-3.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (84 commits) MAINTAINERS: remove drivers/staging/hv/ misc/st_kim: Free resources in the error path of probe() drivers/char: for hpet, add count checking, and ~0UL instead of -1 w1-gpio: Simplify & get rid of defines w1-gpio: Pinctrl-fy extcon: remove use of __devexit_p extcon: remove use of __devinit extcon: remove use of __devexit drivers: uio: Only allocate new private data when probing device tree node drivers: uio_dmem_genirq: Allow partial success when opening device drivers: uio_dmem_genirq: Don't use DMA_ERROR_CODE to indicate unmapped regions drivers: uio_dmem_genirq: Don't mix address spaces for dynamic region vaddr uio: remove use of __devexit uio: remove use of __devinitdata uio: remove use of __devinit uio: remove use of __devexit_p char: remove use of __devexit char: remove use of __devinitconst char: remove use of __devinitdata char: remove use of __devinit ...
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@@ -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 ~0.
+ </para>
+</sect1>
+
</chapter>
<chapter id="userspace_driver" xreflabel="Writing a driver in user space">
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