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

[Joe Hershberger]

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.

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

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