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| author | Kumar Gala <galak@kernel.crashing.org> | 2012-03-14 04:49:34 (GMT) |
|---|---|---|
| committer | Emil Medve <Emilian.Medve@Freescale.com> | 2013-04-01 20:01:25 (GMT) |
| commit | bc902cf1a0351d9d6c43bc9bdd9548431240a385 (patch) | |
| tree | 9a2a5929ae63bac412478be4ed1e1bb1df432406 /Documentation/DocBook | |
| parent | c781ee40b6efbcedf2b719fb746c3346ace5342f (diff) | |
| download | linux-fsl-qoriq-bc902cf1a0351d9d6c43bc9bdd9548431240a385.tar.xz | |
uio: Allow drivers to override the pgprot for mmap()
For some devices, the default behavior of pgprot_noncached() is not
appropriate for all of its mappable regions. This provides a means for
the kernel side of the UIO driver to override the flags without having
to implement its own full mmap callback.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Geoff Thorpe <geoff@geoffthorpe.net>
Signed-off-by: Emil Medve <Emilian.Medve@Freescale.com>
Diffstat (limited to 'Documentation/DocBook')
| -rw-r--r-- | Documentation/DocBook/uio-howto.tmpl | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/Documentation/DocBook/uio-howto.tmpl b/Documentation/DocBook/uio-howto.tmpl index ddb05e9..e23f986 100644 --- a/Documentation/DocBook/uio-howto.tmpl +++ b/Documentation/DocBook/uio-howto.tmpl @@ -510,6 +510,18 @@ interrupts from userspace by writing to <filename>/dev/uioX</filename>, you can implement this function. The parameter <varname>irq_on</varname> will be 0 to disable interrupts and 1 to enable them. </para></listitem> + +<listitem><para> +<varname>pgprot_t (*set_pgprot)(struct uio_info *info, unsigned int mem_idx, +pgprot_t prot)</varname>: Optional. If special flags are required when mapping +certain hardware regions, then this callback can be used to specify those flags. +The default flags are given by the host architecture's definition of +<function>pgprot_noncached()</function> and are passed to the callback as the +<varname>prot</varname> parameter, but the return value is what is used for the +resulting mapping. Note that this callback is only used by the built in mapping +logic (when the <function>mmap()</function> callback has not been set), and then +only for UIO_MEM_PHYS regions. +</para></listitem> </itemizedlist> <para> |