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

Stefano Babic sbabic at denx.de
Tue Sep 9 15:10:24 CEST 2014


On 25/08/2014 18:34, 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 at freescale.com>
> ---

Applied to u-boot-imx, thanks !

Best regards,
Stefano Babic

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