Re: [PATCH 3.4 115/176] spi: dw: Fix detecting FIFO depth

[Zefan Li]

On 2015/4/9 17:37, Axel Lin wrote:
> 2015-04-09 16:46 GMT+08:00  <lizf@xxxxxxxxxx>:
>> From: Axel Lin <axel.lin@xxxxxxxxxx>
>>
>> 3.4.107-rc1 review patch.  If anyone has any objections, please let me know.
>>
>> ------------------
>>
>>
>> commit d297933cc7fcfbaaf2d37570baac73287bf0357d upstream.
>>
>> Current code tries to find the highest valid fifo depth by checking the value
>> it wrote to DW_SPI_TXFLTR. There are a few problems in current code:
>> 1) There is an off-by-one in dws->fifo_len setting because it assumes the latest
>>    register write fails so the latest valid value should be fifo - 1.
>> 2) We know the depth could be from 2 to 256 from HW spec, so it is not necessary
>>    to test fifo == 257. In the case fifo is 257, it means the latest valid
>>    setting is fifo = 256. So after the for loop iteration, we should check
>>    fifo == 2 case instead of fifo == 257 if detecting the FIFO depth fails.
>> This patch fixes above issues.
>>
>> Signed-off-by: Axel Lin <axel.lin@xxxxxxxxxx>
>> Reviewed-and-tested-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
>> Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
>> [lizf: Backported to 3.4: adjust context]
>> Signed-off-by: Zefan Li <lizefan@xxxxxxxxxx>
> 
> Hi,
> This patch needs below fix:
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/drivers/spi/spi-dw.c?id=9d239d353c319f9ff884c287ce47feb7cdf60ddc
> 

Already queued. :)

See "[PATCH 3.4 173/176] spi: dw: revisit FIFO size detection again"

Thanks for your review!

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