[PATCH v2] net: tsec: add option to set device max-speed via dts

[Aleksandar Gerasimovski]

Current tsec adapter sets adapter gigabit capabilities by default, and in
reality this must not always be the case.
It is possible that tsec adapter is used for 100Mbit connection, and in
this case setting 1000Mbit capabilities can lead to some side effects such
longer autoneg process.

In our ls102x designs this problem leads to long autoneg times (> 4 sec)
in case board rgmii link is 100Mbs capble only.
Limiting the rgmii link capabilities provides smother and faster
link establishment.

Signed-off-by: Aleksandar Gerasimovski <aleksandar.gerasimovski at hitachi-powergrids.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean at nxp.com>
---
Changes for v2:
  - keep the variable sort order in a decreasing order of line length
  - fix comment typo
---
 drivers/net/tsec.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/net/tsec.c b/drivers/net/tsec.c
index c68e4b7..ee820aa 100644
--- a/drivers/net/tsec.c
+++ b/drivers/net/tsec.c
@@ -828,6 +828,7 @@ int tsec_probe(struct udevice *dev)
 	const char *phy_mode;
 	ofnode parent, child;
 	fdt_addr_t reg;
+	u32 max_speed;
 	int ret;
 
 	data = (struct tsec_data *)dev_get_driver_data(dev);
@@ -893,8 +894,12 @@ int tsec_probe(struct udevice *dev)
 	}
 	priv->interface = pdata->phy_interface;
 
+	/* Check for speed limit, default is 1000Mbps */
+	max_speed = dev_read_u32_default(dev, "max-speed", 1000);
+
 	/* Initialize flags */
-	priv->flags = TSEC_GIGABIT;
+	if (max_speed == 1000)
+		priv->flags = TSEC_GIGABIT;
 	if (priv->interface == PHY_INTERFACE_MODE_SGMII)
 		priv->flags |= TSEC_SGMII;
 
-- 
1.8.3.1

-----Original Message-----
From: Vladimir Oltean <vladimir.oltean at nxp.com> 
Sent: Freitag, 4. Juni 2021 13:29
To: Aleksandar Gerasimovski <aleksandar.gerasimovski at hitachi-powergrids.com>
Cc: u-boot at lists.denx.de; Priyanka Jain (OSS) <priyanka.jain at oss.nxp.com>; Rainer Boschung <rainer.boschung at hitachi-powergrids.com>; Ramon Fried <rfried.dev at gmail.com>
Subject: Re: [PATCH] net: tsec: add option to set device max-speed via dts

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On Fri, Jun 04, 2021 at 11:13:36AM +0000, Aleksandar Gerasimovski wrote:
> Current tsec adapter sets adapter gigabit capabilities by default, and 
> in reality this must not always be the case.
> It is possible that tsec adapter is used for 100Mbit connection, and 
> in this case setting 1000Mbit capabilities can lead to some side 
> effects such longer autoneg process.
>
> In our ls102x designs this problem leads to long autoneg times (> 4 
> sec) in case board rgmii link is 100Mbs capble only.
> Limiting the rgmii link capabilities provides smother and faster link 
> establishment.
>
> Signed-off-by: Aleksandar Gerasimovski 
> <aleksandar.gerasimovski at hitachi-powergrids.com>
> ---

Reviewed-by: Vladimir Oltean <vladimir.oltean at nxp.com>

Just one comment below:

>  drivers/net/tsec.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/tsec.c b/drivers/net/tsec.c index 
> c68e4b7..501390f 100644
> --- a/drivers/net/tsec.c
> +++ b/drivers/net/tsec.c
> @@ -824,6 +824,7 @@ int tsec_probe(struct udevice *dev)
>       struct tsec_private *priv = dev_get_priv(dev);
>       struct ofnode_phandle_args phandle_args;
>       u32 tbiaddr = CONFIG_SYS_TBIPA_VALUE;
> +     u32 max_speed;

It would be nice if you could keep the variable sort order, which is in decreasing order of line length (so-called "reverse Christmas tree notation").

>       struct tsec_data *data;
>       const char *phy_mode;
>       ofnode parent, child;
> @@ -893,8 +894,12 @@ int tsec_probe(struct udevice *dev)
>       }
>       priv->interface = pdata->phy_interface;
>
> +     /* Check for speed limis, default is 1000Mbps */
> +     max_speed = dev_read_u32_default(dev, "max-speed", 1000);
> +
>       /* Initialize flags */
> -     priv->flags = TSEC_GIGABIT;
> +     if (max_speed == 1000)
> +             priv->flags = TSEC_GIGABIT;
>       if (priv->interface == PHY_INTERFACE_MODE_SGMII)
>               priv->flags |= TSEC_SGMII;
>
> --
> 1.8.3.1

Thanks.