[U-Boot] [PATCH v7 2/2] net: fec_mxc: Poll FEC_TBD_READY after polling TDAR

Marek Vasut
2014-08-25T19:51:31Z

On Monday, August 25, 2014 at 06:34:17 PM, Fabio Estevam wrote:
> When testing the FEC driver on a mx6solox we noticed that the TDAR bit gets
> always cleared prior then the READY bit is cleared in the last BD, which
> causes FEC packets reception to always fail.
>
> As explained by Ye Li:
>
> "The TDAR bit is cleared when the descriptors are all out from TX ring, but
> on mx6solox we noticed that the READY bit is still not cleared right after
> TDAR. These are two distinct signals, and in IC simulation, we found that
> TDAR always gets cleared prior than the READY bit of last BD becomes
> cleared.
> In mx6solox, we use a later version of FEC IP. It looks like that this
> intrinsic behaviour of TDAR bit has changed in this newer FEC version."
>
> Fix this by polling the READY bit of BD after the TDAR polling, which
> covers the mx6solox case and does not harm the other SoCs.
>
> No performance drop has been noticed with this patch applied when testing
> TFTP transfers on several boards of different i.mx SoCs.
>
> Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>

Acked-by: Marek Vasut <marex@denx.de>

Best regards,
Marek Vasut