Re: [PATCHv2 2/2] net: fec: Reset ethernet PHY whenever the enet_out clock is being enabled

[Lucas Stach]

Am Dienstag, den 12.01.2016, 16:17 +0100 schrieb Lothar WaÃmann:
> If a PHY uses ENET_OUT as reference clock, it may need a RESET to get
> functional after the clock had been disabled.
> 
> Failure to do this results in the link state constantly toggling
> between up and down:
> fec 02188000.ethernet eth0: Link is Up - 100Mbps/Full - flow control rx/tx
> fec 02188000.ethernet eth0: Link is Down
> fec 02188000.ethernet eth0: Link is Up - 100Mbps/Full - flow control rx/tx
> fec 02188000.ethernet eth0: Link is Down
> [...]
> 
> Signed-off-by: Lothar WaÃmann <LW@xxxxxxxxxxxxxxxxxxx>
> ---
>  drivers/net/ethernet/freescale/fec.h      |  1 +
>  drivers/net/ethernet/freescale/fec_main.c | 38 +++++++++++++++++++++++++------
>  2 files changed, 32 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/net/ethernet/freescale/fec.h b/drivers/net/ethernet/freescale/fec.h
> index 99d33e2..33228df 100644
> --- a/drivers/net/ethernet/freescale/fec.h
> +++ b/drivers/net/ethernet/freescale/fec.h
> @@ -519,6 +519,7 @@ struct fec_enet_private {
>  	int	pause_flag;
>  	int	wol_flag;
>  	u32	quirks;
> +	int	phy_reset_gpio;
>  
>  	struct	napi_struct napi;
>  	int	csum_flags;
> diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
> index 592a7a4..fb0b0eb 100644
> --- a/drivers/net/ethernet/freescale/fec_main.c
> +++ b/drivers/net/ethernet/freescale/fec_main.c
> @@ -67,6 +67,7 @@
>  
>  static void set_multicast_list(struct net_device *ndev);
>  static void fec_enet_itr_coal_init(struct net_device *ndev);
> +static void fec_reset_phy(struct platform_device *pdev);
>  
>  #define DRIVER_NAME	"fec"
>  
> @@ -1862,6 +1863,8 @@ static int fec_enet_clk_enable(struct net_device *ndev, bool enable)
>  			ret = clk_prepare_enable(fep->clk_enet_out);
>  			if (ret)
>  				goto failed_clk_enet_out;
> +
> +			fec_reset_phy(fep->pdev);
>  		}
>  		if (fep->clk_ptp) {
>  			mutex_lock(&fep->ptp_clk_mutex);
> @@ -3216,11 +3219,12 @@ static int fec_enet_init(struct net_device *ndev)
>  #ifdef CONFIG_OF
>  static void fec_reset_phy(struct platform_device *pdev)
>  {
> -	int err, phy_reset;
> -	int msec = 1;
> +	struct net_device *ndev = platform_get_drvdata(pdev);
> +	struct fec_enet_private *fep = netdev_priv(ndev);
>  	struct device_node *np = pdev->dev.of_node;
> +	int msec = 1;
>  
> -	if (!np)
> +	if (!gpio_is_valid(fep->phy_reset_gpio))
>  		return;
>  
>  	of_property_read_u32(np, "phy-reset-duration", &msec);

While this isn't in a hot path I still want to see this
of_property_read() moved to the fec_get_reset_gpio() function below.
It's really inconsistent otherwise.


> @@ -3228,18 +3232,27 @@ static void fec_reset_phy(struct platform_device *pdev)
>  	if (msec > 1000)
>  		msec = 1;
>  
> +	gpio_set_value_cansleep(fep->phy_reset_gpio, 0);
> +	msleep(msec);
> +	gpio_set_value_cansleep(fep->phy_reset_gpio, 1);
> +}
> +
> +static int fec_get_reset_gpio(struct platform_device *pdev)
> +{
> +	int err, phy_reset;
> +	struct device_node *np = pdev->dev.of_node;
> +
>  	phy_reset = of_get_named_gpio(np, "phy-reset-gpios", 0);
>  	if (!gpio_is_valid(phy_reset))
> -		return;
> +		return phy_reset;
>  
>  	err = devm_gpio_request_one(&pdev->dev, phy_reset,
>  				    GPIOF_OUT_INIT_LOW, "phy-reset");
>  	if (err) {
>  		dev_err(&pdev->dev, "failed to get phy-reset-gpios: %d\n", err);
> -		return;
> +		return err;
>  	}
> -	msleep(msec);
> -	gpio_set_value_cansleep(phy_reset, 1);
> +	return phy_reset;
>  }
>  #else /* CONFIG_OF */
>  static void fec_reset_phy(struct platform_device *pdev)
> @@ -3249,6 +3262,11 @@ static void fec_reset_phy(struct platform_device *pdev)
>  	 * by machine code.
>  	 */
>  }
> +
> +static inline int fec_get_reset_gpio(struct platform_device *pdev)
> +{
> +	return -EINVAL;
> +}
>  #endif /* CONFIG_OF */
>  
>  static void
> @@ -3339,6 +3357,11 @@ fec_probe(struct platform_device *pdev)
>  
>  	platform_set_drvdata(pdev, ndev);
>  
> +	ret = fec_get_reset_gpio(pdev);
> +	if (ret == -EPROBE_DEFER)
> +		goto gpio_defer;
> +	fep->phy_reset_gpio = ret;
> +
>  	if (of_get_property(np, "fsl,magic-packet", NULL))
>  		fep->wol_flag |= FEC_WOL_HAS_MAGIC_PACKET;
>  
> @@ -3493,6 +3516,7 @@ failed_clk_ipg:
>  failed_clk:
>  failed_phy:
>  	of_node_put(phy_node);
> +gpio_defer:
>  failed_ioremap:
>  	free_netdev(ndev);
>  

-- 
Pengutronix e.K.             | Lucas Stach                 |
Industrial Linux Solutions   | http://www.pengutronix.de/  |