Re: [PATCH 5.10 46/52] net: stmmac: power up/down serdes in stmmac_open/release

From: Pavel Machek
Date: Tue Oct 04 2022 - 06:16:40 EST


Hi!

> The issue is related with serdes which impacts clock. There is
> serdes in ADLink I-Pi SMARC board ethernet controller. Please refer to
> commit b9663b7ca6ff78 ("net: stmmac: Enable SERDES power up/down sequence")
> for detial. When issue is reproduced, DMA engine clock is not ready
> because serdes is not powered up.

I don't believe you got the error handling right.

> index 27b7bb64a028..41e71a26b1ad 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -2907,6 +2907,15 @@ static int stmmac_open(struct net_device *dev)
> goto init_error;
> }
>
> + if (priv->plat->serdes_powerup) {
> + ret = priv->plat->serdes_powerup(dev, priv->plat->bsp_priv);
> + if (ret < 0) {
> + netdev_err(priv->dev, "%s: Serdes powerup failed\n",
> + __func__);
> + goto init_error;
> + }
> + }

Ok, so serdes is powered up here.

> ret = stmmac_hw_setup(dev, true);
> if (ret < 0) {
> netdev_err(priv->dev, "%s: Hw setup failed\n",

But this goes to init_error, and exits w/o powering serdes down. Error
handling needs to be fixed AFAICT.

Best regards,
Pavel
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