Subject: Re: [PATCH v6 net-next 3/5] drivers/net/phy: add connection between ethtool and phylib for PLCA

From: "Russell King (Oracle)" <[email-masked]>
Date: Sun, 11 Dec 2022 12:23:53 +0000

On Sat, Dec 10, 2022 at 11:46:39PM +0100, Piergiorgio Beruto wrote:
> This patch adds the required connection between netlink ethtool and
> phylib to resolve PLCA get/set config and get status messages.
> 
> Signed-off-by: Piergiorgio Beruto <[email-masked]>
> ---
>  drivers/net/phy/phy.c        | 175 +++++++++++++++++++++++++++++++++++
>  drivers/net/phy/phy_device.c |   3 +
>  include/linux/phy.h          |   7 ++
>  3 files changed, 185 insertions(+)
> 
> diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
> index e5b6cb1a77f9..40d90ed2f0fb 100644
> --- a/drivers/net/phy/phy.c
> +++ b/drivers/net/phy/phy.c
> @@ -543,6 +543,181 @@ int phy_ethtool_get_stats(struct phy_device *phydev,
>  }
>  EXPORT_SYMBOL(phy_ethtool_get_stats);
>  
> +/**
> + * phy_ethtool_get_plca_cfg - Get PLCA RS configuration
> + *

You shouldn't have an empty line in the comment here

> + * @phydev: the phy_device struct
> + * @plca_cfg: where to store the retrieved configuration

Maybe have an empty line, followed by a bit of text describing what this
function does and the return codes it generates?

> + */
> +int phy_ethtool_get_plca_cfg(struct phy_device *phydev,
> +			     struct phy_plca_cfg *plca_cfg)
> +{
> +	int ret;
> +
> +	if (!phydev->drv) {
> +		ret = -EIO;
> +		goto out;
> +	}
> +
> +	if (!phydev->drv->get_plca_cfg) {
> +		ret = -EOPNOTSUPP;
> +		goto out;
> +	}
> +
> +	memset(plca_cfg, 0xFF, sizeof(*plca_cfg));
> +
> +	mutex_lock(&phydev->lock);

Maybe move the memset() and mutex_lock() before the first if() statement
above? Maybe the memset() should be done by plca_get_cfg_prepare_data()?
Wouldn't all implementations need to memset this to 0xff?

Also, lower-case 0xff please.

> +	ret = phydev->drv->get_plca_cfg(phydev, plca_cfg);
> +
> +	if (ret)
> +		goto out_drv;
> +
> +out_drv:

This if() and out_drv label seems unused (although with the above
suggested change, you will need to move the "out" label here.)

> +	mutex_unlock(&phydev->lock);
> +out:
> +	return ret;
> +}
> +
> +/**
> + * phy_ethtool_set_plca_cfg - Set PLCA RS configuration
> + *
> + * @phydev: the phy_device struct
> + * @extack: extack for reporting useful error messages
> + * @plca_cfg: new PLCA configuration to apply
> + */
> +int phy_ethtool_set_plca_cfg(struct phy_device *phydev,
> +			     const struct phy_plca_cfg *plca_cfg,
> +			     struct netlink_ext_ack *extack)
> +{
> +	int ret;
> +	struct phy_plca_cfg *curr_plca_cfg = 0;

Unnecessary initialiser. Also, reverse Christmas-tree please.

> +
> +	if (!phydev->drv) {
> +		ret = -EIO;
> +		goto out;
> +	}
> +
> +	if (!phydev->drv->set_plca_cfg ||
> +	    !phydev->drv->get_plca_cfg) {
> +		ret = -EOPNOTSUPP;
> +		goto out;
> +	}
> +
> +	curr_plca_cfg = kmalloc(sizeof(*curr_plca_cfg), GFP_KERNEL);

What if kmalloc() returns NULL?

> +	memset(curr_plca_cfg, 0xFF, sizeof(*curr_plca_cfg));
> +
> +	mutex_lock(&phydev->lock);

Consider moving the above three to the beginning of the function so
phydev->drv is checked under the mutex.

> +
> +	ret = phydev->drv->get_plca_cfg(phydev, curr_plca_cfg);
> +	if (ret)
> +		goto out_drv;
> +
> +	if (curr_plca_cfg->enabled < 0 && plca_cfg->enabled >= 0) {
> +		NL_SET_ERR_MSG(extack,
> +			       "PHY does not support changing the PLCA 'enable' attribute");
> +		ret = -EINVAL;
> +		goto out_drv;
> +	}
> +
> +	if (curr_plca_cfg->node_id < 0 && plca_cfg->node_id >= 0) {
> +		NL_SET_ERR_MSG(extack,
> +			       "PHY does not support changing the PLCA 'local node ID' attribute");
> +		ret = -EINVAL;
> +		goto out_drv;
> +	}
> +
> +	if (curr_plca_cfg->node_cnt < 0 && plca_cfg->node_cnt >= 0) {
> +		NL_SET_ERR_MSG(extack,
> +			       "PHY does not support changing the PLCA 'node count' attribute");
> +		ret = -EINVAL;
> +		goto out_drv;
> +	}
> +
> +	if (curr_plca_cfg->to_tmr < 0 && plca_cfg->to_tmr >= 0) {
> +		NL_SET_ERR_MSG(extack,
> +			       "PHY does not support changing the PLCA 'TO timer' attribute");
> +		ret = -EINVAL;
> +		goto out_drv;
> +	}
> +
> +	if (curr_plca_cfg->burst_cnt < 0 && plca_cfg->burst_cnt >= 0) {
> +		NL_SET_ERR_MSG(extack,
> +			       "PHY does not support changing the PLCA 'burst count' attribute");
> +		ret = -EINVAL;
> +		goto out_drv;
> +	}
> +
> +	if (curr_plca_cfg->burst_tmr < 0 && plca_cfg->burst_tmr >= 0) {
> +		NL_SET_ERR_MSG(extack,
> +			       "PHY does not support changing the PLCA 'burst timer' attribute");
> +		ret = -EINVAL;
> +		goto out_drv;
> +	}
> +
> +	// if enabling PLCA, perform additional sanity checks
> +	if (plca_cfg->enabled > 0) {
> +		if (!linkmode_test_bit(ETHTOOL_LINK_MODE_10baseT1S_P2MP_Half_BIT,
> +				       phydev->advertising)) {
> +			ret = -EOPNOTSUPP;
> +			NL_SET_ERR_MSG(extack,
> +				       "Point to Multi-Point mode is not enabled");
> +		}
> +
> +		// allow setting node_id concurrently with enabled
> +		if (plca_cfg->node_id >= 0)
> +			curr_plca_cfg->node_id = plca_cfg->node_id;
> +
> +		if (curr_plca_cfg->node_id >= 255) {
> +			NL_SET_ERR_MSG(extack, "PLCA node ID is not set");
> +			ret = -EINVAL;
> +			goto out_drv;
> +		}
> +	}
> +
> +	ret = phydev->drv->set_plca_cfg(phydev, plca_cfg);
> +	if (ret)
> +		goto out_drv;

Unnecessary if() statement.

> +
> +out_drv:
> +	kfree(curr_plca_cfg);
> +	mutex_unlock(&phydev->lock);
> +out:
> +	return ret;
> +}
> +
> +/**
> + * phy_ethtool_get_plca_status - Get PLCA RS status information
> + *
> + * @phydev: the phy_device struct
> + * @plca_st: where to store the retrieved status information
> + */
> +int phy_ethtool_get_plca_status(struct phy_device *phydev,
> +				struct phy_plca_status *plca_st)
> +{
> +	int ret;
> +
> +	if (!phydev->drv) {
> +		ret = -EIO;
> +		goto out;
> +	}
> +
> +	if (!phydev->drv->get_plca_status) {
> +		ret = -EOPNOTSUPP;
> +		goto out;
> +	}
> +
> +	mutex_lock(&phydev->lock);

Same comment here.

> +	ret = phydev->drv->get_plca_status(phydev, plca_st);
> +
> +	if (ret)
> +		goto out_drv;

And here.

> +
> +out_drv:
> +	mutex_unlock(&phydev->lock);
> +out:
> +	return ret;
> +}
> +
>  /**
>   * phy_start_cable_test - Start a cable test
>   *
> diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
> index 8e48b3cec5e7..44bd06be9691 100644
> --- a/drivers/net/phy/phy_device.c
> +++ b/drivers/net/phy/phy_device.c
> @@ -3276,6 +3276,9 @@ static const struct ethtool_phy_ops phy_ethtool_phy_ops = {
>  	.get_sset_count		= phy_ethtool_get_sset_count,
>  	.get_strings		= phy_ethtool_get_strings,
>  	.get_stats		= phy_ethtool_get_stats,
> +	.get_plca_cfg		= phy_ethtool_get_plca_cfg,
> +	.set_plca_cfg		= phy_ethtool_set_plca_cfg,
> +	.get_plca_status	= phy_ethtool_get_plca_status,
>  	.start_cable_test	= phy_start_cable_test,
>  	.start_cable_test_tdr	= phy_start_cable_test_tdr,
>  };
> diff --git a/include/linux/phy.h b/include/linux/phy.h
> index 2a5c2d3a5da5..e0dcd534fe6f 100644
> --- a/include/linux/phy.h
> +++ b/include/linux/phy.h
> @@ -1845,6 +1845,13 @@ int phy_ethtool_get_strings(struct phy_device *phydev, u8 *data);
>  int phy_ethtool_get_sset_count(struct phy_device *phydev);
>  int phy_ethtool_get_stats(struct phy_device *phydev,
>  			  struct ethtool_stats *stats, u64 *data);
> +int phy_ethtool_get_plca_cfg(struct phy_device *phydev,
> +			     struct phy_plca_cfg *plca_cfg);
> +int phy_ethtool_set_plca_cfg(struct phy_device *phydev,
> +			     const struct phy_plca_cfg *plca_cfg,
> +			     struct netlink_ext_ack *extack);
> +int phy_ethtool_get_plca_status(struct phy_device *phydev,
> +				struct phy_plca_status *plca_st);
>  
>  static inline int phy_package_read(struct phy_device *phydev, u32 regnum)
>  {
> -- 
> 2.37.4
> 
> 

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