[PATCH 2/5] Documentation: Update documentation for UIO_MEM_PHYS_CACHE

Russell King - ARM Linux linux at arm.linux.org.uk
Sun Sep 14 13:01:52 PDT 2014


On Tue, Sep 09, 2014 at 03:26:56PM +0530, Ankit Jindal wrote:
> This patch update UIO documentation for new mem region
> type UIO_MEM_PHYS_CACHE.
> 
> Signed-off-by: Ankit Jindal <ankit.jindal at linaro.org>
> Signed-off-by: Tushar Jagad <tushar.jagad at linaro.org>
> ---
>  Documentation/DocBook/uio-howto.tmpl |    3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/DocBook/uio-howto.tmpl b/Documentation/DocBook/uio-howto.tmpl
> index bbe9c1f..49e47d4 100644
> --- a/Documentation/DocBook/uio-howto.tmpl
> +++ b/Documentation/DocBook/uio-howto.tmpl
> @@ -530,7 +530,8 @@ the memory region, it will show up in the corresponding sysfs node.
>  <varname>UIO_MEM_PHYS</varname> if you you have physical memory on your
>  card to be mapped. Use <varname>UIO_MEM_LOGICAL</varname> for logical
>  memory (e.g. allocated with <function>kmalloc()</function>). There's also
> -<varname>UIO_MEM_VIRTUAL</varname> for virtual memory.
> +<varname>UIO_MEM_VIRTUAL</varname> for virtual memory and
> +<varname>UIO_MEM_PHYS_CACHE</varname> for physical cacheable memory.

When I read this, I wondered what "physical cacheable memory" was.
Then I found that what you're doing with this is mapping physical
memory into userspace with cacheable attributes.

So, to avoid confusion, this should be "for physical memory, which
will be cacheably mapped" or similar.

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