DMA_BIT_MASK Operation in Kernel

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hi all,

I am working in linux device driver, i have seen a macro DMA_BIT_MASK(32), can any one tell me function of this macro in kernel

Thanks,
shan

[edit]SHOUTING removed - OriginalGriff[/edit]

Posted 3-Jul-13 4:24am

shan bala

Updated 3-Jul-13 4:55am

OriginalGriff

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OriginalGriff 3-Jul-13 10:55am

DON'T SHOUT. Using all capitals is considered shouting on the internet, and rude (using all lower case is considered childish). Use proper capitalisation if you want to be taken seriously.

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OriginalGriff · Accepted Answer · 2013-07-03T05:00:00

Google is your friend: Be nice and visit him often. He can answer questions a lot more quickly than posting them here...

A very quick search using just DMA_BIT_MASK as the search term gave 23,000 hits: Google DMA_BIT_MASK[^]

The top hit took me to Linux Crsoss reference, http://lxr.free-electrons.com/ident?v=2.6.34;i=DMA_BIT_MASK[^] which links to the definition: http://lxr.free-electrons.com/source/include/linux/dma-mapping.h?v=2.6.34#L65[^] which shows the whole macro.

A quick glance tells you exactly what it does! I.e. converts a bit number to a bit mask.

In future, please try to do at least basic research yourself, and not waste your time or ours.

DMA_BIT_MASK Operation in Kernel

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