netdev - Re: [PATCH net-next 1/4] drivers: net: xgene-v2: Add MDIO support

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Date:   Tue, 21 Mar 2017 21:35:50 +0100
From:   Andrew Lunn <andrew@...n.ch>
To:     Iyappan Subramanian <isubramanian@....com>
Cc:     davem@...emloft.net, netdev@...r.kernel.org, f.fainelli@...il.com,
        David.Laight@...lab.com, linux-arm-kernel@...ts.infradead.org,
        patches@....com, kchudgar@....com
Subject: Re: [PATCH net-next 1/4] drivers: net: xgene-v2: Add MDIO support

> @@ -511,9 +512,9 @@ static int xge_close(struct net_device *ndev)
>  {
>  	struct xge_pdata *pdata = netdev_priv(ndev);
>  
> -	netif_carrier_off(ndev);
>  	netif_stop_queue(ndev);
>  	xge_mac_disable(pdata);
> +	phy_stop(ndev->phydev);
>  
>  	xge_intr_disable(pdata);
>  	xge_free_irq(ndev);
> @@ -683,9 +684,14 @@ static int xge_probe(struct platform_device *pdev)
>  	if (ret)
>  		goto err;
>  
> +	spin_lock_init(&pdata->mdio_lock);
> +

...

> +static int xge_mdio_write(struct mii_bus *bus, int phy_id, int reg, u16 data)
> +{
> +	struct xge_pdata *pdata = bus->priv;
> +	u32 done, val = 0;
> +	u8 wait = 10;
> +	int ret = 0;
> +
> +	spin_lock(&pdata->mdio_lock);
> +
> +	SET_REG_BITS(&val, PHY_ADDR, phy_id);
> +	SET_REG_BITS(&val, REG_ADDR, reg);
> +	xge_wr_csr(pdata, MII_MGMT_ADDRESS, val);
> +
> +	xge_wr_csr(pdata, MII_MGMT_CONTROL, data);
> +	do {
> +		usleep_range(5, 10);
> +		done = xge_rd_csr(pdata, MII_MGMT_INDICATORS);
> +	} while ((done & MII_MGMT_BUSY) && wait--);
> +
> +	if (done & MII_MGMT_BUSY) {
> +		dev_err(&bus->dev, "MII_MGMT write failed\n");
> +		ret = -ETIMEDOUT;
> +	}
> +
> +	spin_unlock(&pdata->mdio_lock);
> +
> +	return ret;
> +}
> +
> +static int xge_mdio_read(struct mii_bus *bus, int phy_id, int reg)
> +{
> +	struct xge_pdata *pdata = bus->priv;
> +	u32 data, done, val = 0;
> +	u8 wait = 10;
> +
> +	spin_lock(&pdata->mdio_lock);
> +

Hi Iyappan

Please could you explain what this lock is protecting which the
mii_bus mdio_lock in mdio_bus.c is not protecting?

Thanks
	Andrew