Re: [PATCH] net: can: Remodel FlexCAN register read/write APIs for BE instances

[Marc Kleine-Budde <mkl@pengutronix.de>]

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On 06/25/2014 12:29 PM, David Laight wrote:
>> Ok. Or should I create two functions for read and write - one does it in LE way and the other
>> in BE way and parse the DT to understand which endianness the module supports.
> 
> An indirect call is likely to be slower than a conditional.
> The conditional inside a non-inlined function is likely to get
> predicted correctly on any code paths that matter.
> Unfortunately using a real function increases register pressure.
> 
> Maybe a compile-time option for BE, LE or both.
> So a 'generic' kernel can work, but a SoC specific one will be faster.
> Then have the driver load/attach/init fail if it is the wrong endianness.

Don't overengineer, CAN is max 1 MiB/s.

Marc

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