Subject: Re: [RFC PATCH 2/2] net: macb: Add gmii2rgmii phy converter support

From: Nicolas Ferre <[email-masked]>
Date: Fri, 1 Jul 2016 09:45:26 +0200

Le 01/07/2016 08:20, Kedareswara rao Appana a écrit :
> This patch adds support for gmii2rgmii phy converter
> in the macb driver.

Okay, I'd like more explanation here.
Hints & key words:
- dt property
- mdio bus
- mac speed

> Signed-off-by: Kedareswara rao Appana <[email-masked]>
> ---
>  drivers/net/ethernet/cadence/macb.c |   21 ++++++++++++++++++++-
>  drivers/net/ethernet/cadence/macb.h |    3 +++
>  2 files changed, 23 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/net/ethernet/cadence/macb.c b/drivers/net/ethernet/cadence/macb.c
> index cb07d95..de0ad71 100644
> --- a/drivers/net/ethernet/cadence/macb.c
> +++ b/drivers/net/ethernet/cadence/macb.c
> @@ -257,6 +257,14 @@ static int macb_mdio_write(struct mii_bus *bus, int mii_id, int regnum,
>  	return 0;
>  }
>  
> +static inline void macb_hw_fix_mac_speed(struct macb *bp,
> +					 struct phy_device *phydev)
> +{
> +	if (likely(bp->converter_phy.fix_mac_speed))

What is the purpose of this branch bias? The code isn't in some hot
path, so I suspect that its not needed.

> +		bp->converter_phy.fix_mac_speed(&bp->converter_phy,
> +						phydev->speed);
> +}
> +
>  /**
>   * macb_set_tx_clk() - Set a clock to a new frequency
>   * @clk		Pointer to the clock to change
> @@ -329,6 +337,7 @@ static void macb_handle_link_change(struct net_device *dev)
>  				reg |= GEM_BIT(GBE);
>  
>  			macb_or_gem_writel(bp, NCFGR, reg);
> +			macb_hw_fix_mac_speed(bp, phydev);
>  
>  			bp->speed = phydev->speed;
>  			bp->duplex = phydev->duplex;
> @@ -2884,7 +2893,7 @@ static int macb_probe(struct platform_device *pdev)
>  			struct clk **, struct clk **)
>  					      = macb_clk_init;
>  	int (*init)(struct platform_device *) = macb_init;
> -	struct device_node *np = pdev->dev.of_node;
> +	struct device_node *np = pdev->dev.of_node, *np1, *np11;

Nitpicking:
Be more explicit on variable names. Simple name for the iterator is
okay, the other is better if changed.
I also like to see variable on separated lines.

>  	struct device_node *phy_node;
>  	const struct macb_config *macb_config = NULL;
>  	struct clk *pclk, *hclk = NULL, *tx_clk = NULL;
> @@ -3011,6 +3020,16 @@ static int macb_probe(struct platform_device *pdev)
>  		goto err_out_free_netdev;
>  
>  	phydev = bp->phy_dev;
> +	np1 = of_get_next_child(np, NULL);
> +	for_each_child_of_node(np1, np11) {
> +		if (of_device_is_compatible(np11, "xlnx,gmiitorgmii")) {

This would definitively need documentation and at least link in the macb
binding to show how this emulated phy connect to the mdio bus...

I'm not able to judge if the node arrangement is okay: I let Florian
tell his view on this...

> +			bp->converter_phy.dev = dev;
> +			bp->converter_phy.mii_bus = bp->mii_bus;
> +			bp->converter_phy.mdio_write = macb_mdio_write;
> +			bp->converter_phy.platform_data = bp->pdev->dev.of_node;
> +			gmii2rgmii_phyprobe(&bp->converter_phy);
> +		}
> +	}
>  
>  	netif_carrier_off(dev);
>  
> diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h
> index 8a13824..735bce2 100644
> --- a/drivers/net/ethernet/cadence/macb.h
> +++ b/drivers/net/ethernet/cadence/macb.h
> @@ -10,6 +10,8 @@
>  #ifndef _MACB_H
>  #define _MACB_H
>  
> +#include <linux/xilinx_gmii2rgmii.h>

No, put it in the macb.c.

> +
>  #define MACB_GREGS_NBR 16
>  #define MACB_GREGS_VERSION 2
>  #define MACB_MAX_QUEUES 8
> @@ -846,6 +848,7 @@ struct macb {
>  	unsigned int		jumbo_max_len;
>  
>  	u32			wol;
> +	struct	gmii2rgmii	converter_phy;
>  };
>  
>  static inline bool macb_is_gem(struct macb *bp)

If Florian and phy guys are okay with the approach, I'm fine with this
patch, once corrected.

Thanks, bye,
-- 
Nicolas Ferre