[U-Boot] [PATCH v2] drivers: net: cpsw: always flush cache of size PKTSIZE_ALIGN

[Lokesh Vutla]

On Wednesday 10 August 2016 08:43 AM, Joe Hershberger wrote:
> Hi Lokesh
> 
> On Tue, Aug 9, 2016 at 12:47 AM, Lokesh Vutla <lokeshvutla at ti.com> wrote:
>> cpsw tries to flush dcache which is not in the range of PKTSIZE.
>> Because of this the following warning comes while flushing:
>>
>> CACHE: Misaligned operation at range [dffecec0, dffed016]
>>
>> Fix it by flushing cache of size PKTSIZE_ALIGN as similar to what is
>> being done in _cpsw_recv.
>>
>> Signed-off-by: Lokesh Vutla <lokeshvutla at ti.com>
>> ---
>> Changes since v1:
>> - Use PKTALIGN instead of cache line size
>> - Need not align start of packet buffer from the network subsystem.
>>
>>  drivers/net/cpsw.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/cpsw.c b/drivers/net/cpsw.c
>> index 2ce4ec6..8ce5716 100644
>> --- a/drivers/net/cpsw.c
>> +++ b/drivers/net/cpsw.c
>> @@ -907,7 +907,7 @@ static int _cpsw_send(struct cpsw_priv *priv, void *packet, int length)
>>         int timeout = CPDMA_TIMEOUT;
>>
>>         flush_dcache_range((unsigned long)packet,
>> -                          (unsigned long)packet + length);
>> +                          (unsigned long)packet + PKTSIZE_ALIGN);
> 
> Technically you are flushing more than needed since you just need to
> be aligned to the cacheline beyond the size being sent, but you are
> flushing the maximum packet size every time. That said, it's still
> going to work and the code is readable. I'm fine with this, but wanted
> to make sure you knew this is more flushing than needed.

Initially that was my idea as well and aligned length to cache line
size. As you suggested to use PKTSIZE_ALIGN and also _cpsw_recv uses the
same. So, I used PKTSIZE_ALIGN.

> 
> Acked-by: Joe Hershberger <joe.hershberger at ni.com>

Thanks and regards,
Lokesh

> 
>>         /* first reap completed packets */
>>         while (timeout-- &&
>> --
>> 2.9.2
>>
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