Re: [PATCH 1/3] spi: spi-xilinx: Remove ISR race condition

From: Shubhrajyoti Datta
Date: Fri Dec 04 2015 - 00:23:03 EST


>
>>
>> =============
>> spi: xilinx - minimize iomem reads
>>
>> If this IP core is accessed through bridges like PCI-e, reads are rather
>> costly. Doing many reads or read-modify-writes is thus long and strenuous
>> on the CPU (active waiting).
>>
>> The transfer workflow of this driver allows some assumptions to be made and
>> exploited to minimize reads as much as possible.
>>
>> These two assumptions are made:
>> - since we are in control of the CR register, cache it so we don't have to
>> read it all the time to modify it.
>
> Makes sense.

I have made an attempt at it can you check if you get any performance
improvemets
on your setup.

http://www.spinics.net/lists/linux-spi/msg05963.html


Thanks,
Shubhrajyoti
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