+ Hi Stefan, > -----Original Message----- > From: U-Boot <u-boot-boun...@lists.denx.de> On Behalf Of Stefan Roese > Sent: Wednesday, January 11, 2023 1:01 PM > To: u-boot@lists.denx.de > Cc: Michal Simek <michal.si...@amd.com>; Ramon Fried > <rfried....@gmail.com>; Sean Anderson <sean.ander...@seco.com> > Subject: [PATCH] net: zynq_gem: Add a 10ms delay in zynq_gem_init() > > In our system using ZynqMP with an external SGMII PHY it's necessary to > wait a short while after the configuration in zynq_gem_init() before the xfer > starts. Otherwise the first packet(s) might get dropped, resulting in a delay > at > the start of the ethernet transfers. > > This patch adds a minimal delay of 10ms which fixes problems of dropped > first packages. > > Signed-off-by: Stefan Roese <s...@denx.de> > Cc: Michal Simek <michal.si...@amd.com> > Cc: Ramon Fried <rfried....@gmail.com> > Cc: Sean Anderson <sean.ander...@seco.com> > --- > drivers/net/zynq_gem.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/net/zynq_gem.c b/drivers/net/zynq_gem.c index > 507b19b75975..26e468766871 100644 > --- a/drivers/net/zynq_gem.c > +++ b/drivers/net/zynq_gem.c > @@ -522,6 +522,13 @@ static int zynq_gem_init(struct udevice *dev) > return ret; > } > } > + > + /* > + * Some additional minimal delay seems to be needed so that > + * the first packet will be sent correctly > + */ > + mdelay(10); > +
Thanks for the patch. The PCS status check in your v1 seems valid. However, this delay of 10 msecs should not be necessary. If the PCS status (when autoneg is enabled with the external PHY on your board) shows link up, that's enough. Could you please consider the following to investigate why initial packets are lost? -> If the external PHY on your board has a hardware reset please consider updating the reset-assert-us and reset-deassert-us properties to ensure PHY is ready before access. -> Can you please check if there's any link stability issues in the initial msecs? Monitoring the serdes/GTR SGMII lane that's setup on ZynqMP will be useful. Regards, Harini
