netdev - Re: [PATCH net-next v4 10/10] net: sunhme: Consolidate common probe tasks

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Date:   Sat, 25 Mar 2023 10:10:30 +0100
From:   Simon Horman <simon.horman@...igine.com>
To:     Sean Anderson <seanga2@...il.com>
Cc:     "David S . Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH net-next v4 10/10] net: sunhme: Consolidate common probe
 tasks

On Fri, Mar 24, 2023 at 01:51:36PM -0400, Sean Anderson wrote:
> Most of the second half of the PCI/SBUS probe functions are the same.
> Consolidate them into a common function.
> 
> Signed-off-by: Sean Anderson <seanga2@...il.com>

Hi Sean,

overall this looks good.
But I (still?) have some concerns about handling hm_revision.

...

> diff --git a/drivers/net/ethernet/sun/sunhme.c b/drivers/net/ethernet/sun/sunhme.c
> index bd1925f575c4..ec85aef35bf9 100644
> --- a/drivers/net/ethernet/sun/sunhme.c
> +++ b/drivers/net/ethernet/sun/sunhme.c
> @@ -2430,6 +2430,58 @@ static void happy_meal_addr_init(struct happy_meal *hp,
>  	}
>  }
>  
> +static int happy_meal_common_probe(struct happy_meal *hp,
> +				   struct device_node *dp)
> +{
> +	struct net_device *dev = hp->dev;
> +	int err;
> +
> +#ifdef CONFIG_SPARC
> +	hp->hm_revision = of_getintprop_default(dp, "hm-rev", hp->hm_revision);

Previously the logic, for SPARC for PCI went something like this:

	/* in happy_meal_pci_probe() */
	hp->hm_revision = of_getintprop_default(dp, "hm-rev", 0xff);
	if (hp->hm_revision == 0xff)
		hp->hm_revision = 0xc0 | (pdev->revision & 0x0f);

Now it goes something like this:

	/* in happy_meal_pci_probe() */
	hp->hm_revision = 0xc0 | (pdev->revision & 0x0f);
	/* in happy_meal_common_probe() */
	hp->hm_revision = of_getintprop_default(dp, "hm-rev", hp->hm_revision); 

Is this intentional?

Likewise, for sbus (which implies SPARC) the logic was something like:

	/* in happy_meal_sbus_probe_one() */
	hp->hm_revision = of_getintprop_default(dp, "hm-rev", 0xff);
	if (hp->hm_revision == 0xff)
		 hp->hm_revision = 0xa0;

And now goes something like this:

	/* in happy_meal_pci_probe() */
	hp->hm_revision = 0xa0;
	/* in happy_meal_common_probe() */
	hp->hm_revision = of_getintprop_default(dp, "hm-rev", hp->hm_revision); 

> +#endif
> +
> +	/* Now enable the feature flags we can. */
> +	if (hp->hm_revision == 0x20 || hp->hm_revision == 0x21)
> +		hp->happy_flags |= HFLAG_20_21;
> +	else if (hp->hm_revision != 0xa0)
> +		hp->happy_flags |= HFLAG_NOT_A0;
> +
> +	hp->happy_block = dmam_alloc_coherent(hp->dma_dev, PAGE_SIZE,
> +					      &hp->hblock_dvma, GFP_KERNEL);
> +	if (!hp->happy_block)
> +		return -ENOMEM;
> +
> +	/* Force check of the link first time we are brought up. */
> +	hp->linkcheck = 0;
> +
> +	/* Force timer state to 'asleep' with count of zero. */
> +	hp->timer_state = asleep;
> +	hp->timer_ticks = 0;
> +
> +	timer_setup(&hp->happy_timer, happy_meal_timer, 0);
> +
> +	dev->netdev_ops = &hme_netdev_ops;
> +	dev->watchdog_timeo = 5 * HZ;
> +	dev->ethtool_ops = &hme_ethtool_ops;
> +
> +	/* Happy Meal can do it all... */
> +	dev->hw_features = NETIF_F_SG | NETIF_F_HW_CSUM;
> +	dev->features |= dev->hw_features | NETIF_F_RXCSUM;
> +
> +

nit: one blank line is enough.

> +	/* Grrr, Happy Meal comes up by default not advertising
> +	 * full duplex 100baseT capabilities, fix this.
> +	 */
> +	spin_lock_irq(&hp->happy_lock);
> +	happy_meal_set_initial_advertisement(hp);
> +	spin_unlock_irq(&hp->happy_lock);
> +
> +	err = devm_register_netdev(hp->dma_dev, dev);
> +	if (err)
> +		dev_err(hp->dma_dev, "Cannot register net device, aborting.\n");
> +	return err;
> +}
> +

...