RE: [PATCH v1 net-next] net: stmmac: enable clause 45 mdio support

[Voon, Weifeng]

> > @@ -155,22 +171,26 @@ static int stmmac_mdio_read(struct mii_bus *bus,
> int phyaddr, int phyreg)
> >  	struct stmmac_priv *priv = netdev_priv(ndev);
> >  	unsigned int mii_address = priv->hw->mii.addr;
> >  	unsigned int mii_data = priv->hw->mii.data;
> > -	u32 v;
> > -	int data;
> >  	u32 value = MII_BUSY;
> > +	int data = 0;
> > +	u32 v;
> >
> >  	value |= (phyaddr << priv->hw->mii.addr_shift)
> >  		& priv->hw->mii.addr_mask;
> >  	value |= (phyreg << priv->hw->mii.reg_shift) & priv->hw-
> >mii.reg_mask;
> >  	value |= (priv->clk_csr << priv->hw->mii.clk_csr_shift)
> >  		& priv->hw->mii.clk_csr_mask;
> > -	if (priv->plat->has_gmac4)
> > +	if (priv->plat->has_gmac4) {
> >  		value |= MII_GMAC4_READ;
> > +		if (phyreg & MII_ADDR_C45)
> > +			stmmac_mdio_c45_setup(priv, phyreg, &value, &data);
> > +	}
> >
> >  	if (readl_poll_timeout(priv->ioaddr + mii_address, v, !(v &
> MII_BUSY),
> >  			       100, 10000))
> >  		return -EBUSY;
> >
> > +	writel(data, priv->ioaddr + mii_data);
> 
> That looks odd. Could you explain why it is needed.
> 
> Thanks
> 	Andrew

Hi Andrew,
This mdio c45 support needed to access DWC xPCS which is a Clause-45
MDIO Manageable Device (MMD). This is discuss in:
https://patchwork.ozlabs.org/patch/1109776/
https://patchwork.ozlabs.org/patch/1109777/
Since the patch is still WIP to make the xPCS as PHY driver for SGMII
to RGMII converter. So i decided to upstream this patch first.

Biao Huang also needed this patch and tested pass with this patch on 
their platform.
https://patchwork.ozlabs.org/patch/1103861/

Biao Huang's patch on MDIO-c45 access 
https://patchwork.ozlabs.org/patch/1092436/ 

Regards,
Weifeng