Re: [PATCH net next] net: axienet: Use dedicated ethtool_ops for the dmaengine path

[Jacob Keller <jacob.e.keller@intel.com>]

On 6/1/2026 5:44 AM, Suraj Gupta wrote:
> The dmaengine path shares ethtool_ops with the legacy AXI DMA path,
> including .get_coalesce/.set_coalesce that poke XAXIDMA_*_CR_OFFSET
> directly. In dmaengine mode lp->dma_regs is not mapped by axienet, so
> those ethtool calls touch unmapped/unrelated memory and report values
> unrelated to the channel actually in use.
> 
> .get_ringparam/.set_ringparam only touch lp->rx_bd_num/lp->tx_bd_num,
> fields used only by the legacy path for BD ring sizing. In dmaengine
> mode the descriptor ring is owned by the dmaengine provider and these
> fields are not consulted, so reporting them is misleading.
> 
> No dmaengine API exists today to query or program either coalescing
> or ring size on behalf of the client, so neither can be exposed
> meaningfully in dmaengine mode.
> 
> Add axienet_ethtool_dmaengine_ops without the coalesce and ringparam
> hooks. Also move the ethtool_ops assignment from early probe into the
> if/else alongside netdev_ops, so the legacy and dmaengine paths pick
> their respective ops in one place. No functional change for the
> legacy DMA path.
> 
> Signed-off-by: Suraj Gupta <suraj.gupta2@amd.com>
> ---

Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>

>  .../net/ethernet/xilinx/xilinx_axienet_main.c | 27 ++++++++++++++++---
>  1 file changed, 24 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
> index 263c4b67fd5a..fcf517069d16 100644
> --- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
> +++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
> @@ -2536,6 +2536,25 @@ static const struct ethtool_ops axienet_ethtool_ops = {
>  	.get_rmon_stats = axienet_ethtool_get_rmon_stats,
>  };
>  
> +static const struct ethtool_ops axienet_ethtool_dmaengine_ops = {
> +	.get_drvinfo    = axienet_ethtools_get_drvinfo,
> +	.get_regs_len   = axienet_ethtools_get_regs_len,
> +	.get_regs       = axienet_ethtools_get_regs,
> +	.get_link       = ethtool_op_get_link,
> +	.get_pauseparam = axienet_ethtools_get_pauseparam,
> +	.set_pauseparam = axienet_ethtools_set_pauseparam,
> +	.get_link_ksettings = axienet_ethtools_get_link_ksettings,
> +	.set_link_ksettings = axienet_ethtools_set_link_ksettings,
> +	.nway_reset	= axienet_ethtools_nway_reset,
> +	.get_ethtool_stats = axienet_ethtools_get_ethtool_stats,
> +	.get_strings    = axienet_ethtools_get_strings,
> +	.get_sset_count = axienet_ethtools_get_sset_count,
> +	.get_pause_stats = axienet_ethtools_get_pause_stats,
> +	.get_eth_mac_stats = axienet_ethtool_get_eth_mac_stats,
> +	.get_eth_ctrl_stats = axienet_ethtool_get_eth_ctrl_stats,
> +	.get_rmon_stats = axienet_ethtool_get_rmon_stats,
> +};
> +
>  static struct axienet_local *pcs_to_axienet_local(struct phylink_pcs *pcs)
>  {
>  	return container_of(pcs, struct axienet_local, pcs);
> @@ -2792,7 +2811,6 @@ static int axienet_probe(struct platform_device *pdev)
>  
>  	SET_NETDEV_DEV(ndev, &pdev->dev);
>  	ndev->features = NETIF_F_SG;
> -	ndev->ethtool_ops = &axienet_ethtool_ops;
>  
>  	/* MTU range: 64 - 9000 */
>  	ndev->min_mtu = 64;
> @@ -3021,10 +3039,13 @@ static int axienet_probe(struct platform_device *pdev)
>  		lp->use_dmaengine = 1;
>  	}
>  
> -	if (lp->use_dmaengine)
> +	if (lp->use_dmaengine) {
>  		ndev->netdev_ops = &axienet_netdev_dmaengine_ops;
> -	else
> +		ndev->ethtool_ops = &axienet_ethtool_dmaengine_ops;
> +	} else {
>  		ndev->netdev_ops = &axienet_netdev_ops;
> +		ndev->ethtool_ops = &axienet_ethtool_ops;
> +	}
>  	/* Check for Ethernet core IRQ (optional) */
>  	if (lp->eth_irq <= 0)
>  		dev_info(&pdev->dev, "Ethernet core IRQ not defined\n");