netdev - Re: [PATCH net] net: ftmac100: add multicast filtering possibility

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Date: Tue, 1 Aug 2023 18:07:35 +0300
From: Vladimir Oltean <vladimir.oltean@....com>
To: Sergei Antonov <saproj@...il.com>
Cc: netdev@...r.kernel.org
Subject: Re: [PATCH net] net: ftmac100: add multicast filtering possibility

Hi Sergei,

On Tue, Jul 04, 2023 at 06:40:53PM +0300, Sergei Antonov wrote:
> If netdev_mc_count() is not zero and not IFF_ALLMULTI, filter
> incoming multicast packets. The chip has a Multicast Address Hash Table
> for allowed multicast addresses, so we fill it.
> 
> This change is based on the analogous code from the ftgmac100 driver.
> Although the hashing algorithm is different.
> 
> Signed-off-by: Sergei Antonov <saproj@...il.com>
> ---
>  drivers/net/ethernet/faraday/ftmac100.c | 39 +++++++++++++++++++++++++
>  1 file changed, 39 insertions(+)
> 
> diff --git a/drivers/net/ethernet/faraday/ftmac100.c b/drivers/net/ethernet/faraday/ftmac100.c
> index 139fe66f8bcd..0ecc0a319520 100644
> --- a/drivers/net/ethernet/faraday/ftmac100.c
> +++ b/drivers/net/ethernet/faraday/ftmac100.c
> @@ -149,6 +149,25 @@ static void ftmac100_set_mac(struct ftmac100 *priv, const unsigned char *mac)
>  	iowrite32(laddr, priv->base + FTMAC100_OFFSET_MAC_LADR);
>  }
>  
> +static void ftmac100_setup_mc_ht(struct ftmac100 *priv)
> +{
> +	u32 maht0 = 0; /* Multicast Address Hash Table bits 31:0 */
> +	u32 maht1 = 0; /* ... bits 63:32 */
> +	struct netdev_hw_addr *ha;
> +
> +	netdev_for_each_mc_addr(ha, priv->netdev) {
> +		u32 hash = ~ether_crc_le(ETH_ALEN, ha->addr) >> 26;
> +
> +		if (hash >= 32)
> +			maht1 |= 1 << (hash - 32);
> +		else
> +			maht0 |= 1 << hash;
> +	}
> +
> +	iowrite32(maht0, priv->base + FTMAC100_OFFSET_MAHT0);
> +	iowrite32(maht1, priv->base + FTMAC100_OFFSET_MAHT1);
> +}

Maybe it would look a bit better to remove the if/else like this?

static void ftmac100_setup_mc_ht(struct ftmac100 *priv)
{
	struct netdev_hw_addr *ha;
	u64 maht = 0;

	netdev_for_each_mc_addr(ha, priv->netdev) {
		u32 hash = ~ether_crc_le(ETH_ALEN, ha->addr) >> 26;

		maht |= BIT_ULL(hash);
	}

	iowrite32(lower_32_bits(maht), priv->base + FTMAC100_OFFSET_MAHT0);
	iowrite32(upper_32_bits(maht), priv->base + FTMAC100_OFFSET_MAHT1);
}

Not a huge difference.

You need to repost the patch to net-next anyway.

> +
>  #define MACCR_ENABLE_ALL	(FTMAC100_MACCR_XMT_EN	| \
>  				 FTMAC100_MACCR_RCV_EN	| \
>  				 FTMAC100_MACCR_XDMA_EN	| \
> @@ -187,6 +206,10 @@ static int ftmac100_start_hw(struct ftmac100 *priv)
>  		maccr |= FTMAC100_MACCR_RCV_ALL;
>  	if (netdev->flags & IFF_ALLMULTI)
>  		maccr |= FTMAC100_MACCR_RX_MULTIPKT;
> +	else if (netdev_mc_count(netdev)) {
> +		maccr |= FTMAC100_MACCR_HT_MULTI_EN;
> +		ftmac100_setup_mc_ht(priv);
> +	}
>  
>  	iowrite32(maccr, priv->base + FTMAC100_OFFSET_MACCR);
>  	return 0;
> @@ -1067,6 +1090,21 @@ static int ftmac100_change_mtu(struct net_device *netdev, int mtu)
>  	return 0;
>  }
>  
> +static void ftmac100_set_rx_mode(struct net_device *netdev)
> +{
> +	struct ftmac100 *priv = netdev_priv(netdev);
> +
> +	ftmac100_setup_mc_ht(priv);
> +
> +	if (netdev_mc_count(priv->netdev)) {
> +		unsigned int maccr = ioread32(priv->base + FTMAC100_OFFSET_MACCR);
> +
> +		/* Make sure multicast filtering is enabled */
> +		maccr |= FTMAC100_MACCR_HT_MULTI_EN;
> +		iowrite32(maccr, priv->base + FTMAC100_OFFSET_MACCR);
> +	}
> +}
> +
>  static const struct net_device_ops ftmac100_netdev_ops = {
>  	.ndo_open		= ftmac100_open,
>  	.ndo_stop		= ftmac100_stop,
> @@ -1075,6 +1113,7 @@ static const struct net_device_ops ftmac100_netdev_ops = {
>  	.ndo_validate_addr	= eth_validate_addr,
>  	.ndo_eth_ioctl		= ftmac100_do_ioctl,
>  	.ndo_change_mtu		= ftmac100_change_mtu,
> +	.ndo_set_rx_mode	= ftmac100_set_rx_mode,
>  };
>  
>  /******************************************************************************
> -- 
> 2.37.2
>