Subject: Re: [PATCH intel-net] ixgbe: allow toggling loopback mode via ndo_set_features callback

From: Maciej Fijalkowski <[email-masked]>
Date: Tue, 4 Apr 2023 11:35:57 +0200

On Tue, Mar 21, 2023 at 08:35:24AM +0800, Hao Ma wrote:
> From: Hao Ma <[email-masked]>
> 
> Add support for NETIF_F_LOOPBACK. This feature can be set via:
> $ ethtool -K eth0 loopback <on|off>
> 
> This sets the MAC Tx->Rx loopback used by selftests/bpf/xskxceiver

Can you resend this patch please? It seems it didn't arrive to iwl nor
netdev.

> 
> Signed-off-by: Hao Ma <[email-masked]>
> ---
>  .../net/ethernet/intel/ixgbe/ixgbe_common.c   |  4 +-
>  drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 73 +++++++++++++++++++
>  drivers/net/ethernet/intel/ixgbe/ixgbe_type.h |  1 +
>  3 files changed, 76 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_common.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_common.c
> index 38c4609bd429..a39dd2d11bc8 100644
> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_common.c
> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_common.c
> @@ -3336,7 +3336,7 @@ s32 ixgbe_check_mac_link_generic(struct ixgbe_hw *hw, ixgbe_link_speed *speed,
>  
>  	if (link_up_wait_to_complete) {
>  		for (i = 0; i < IXGBE_LINK_UP_TIME; i++) {
> -			if (links_reg & IXGBE_LINKS_UP) {
> +			if (links_reg & IXGBE_LINKS_UP || hw->loopback_on) {
>  				*link_up = true;
>  				break;
>  			} else {
> @@ -3346,7 +3346,7 @@ s32 ixgbe_check_mac_link_generic(struct ixgbe_hw *hw, ixgbe_link_speed *speed,
>  			links_reg = IXGBE_READ_REG(hw, IXGBE_LINKS);
>  		}
>  	} else {
> -		if (links_reg & IXGBE_LINKS_UP)
> +		if (links_reg & IXGBE_LINKS_UP || hw->loopback_on)
>  			*link_up = true;
>  		else
>  			*link_up = false;
> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> index ab8370c413f3..e5624d1fc6c3 100644
> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> @@ -8874,6 +8874,57 @@ netdev_tx_t ixgbe_xmit_frame_ring(struct sk_buff *skb,
>  	return NETDEV_TX_OK;
>  }
>  
> +static int ixgbe_force_loopback(struct ixgbe_adapter *adapter, bool on)
> +{	struct ixgbe_hw *hw = &adapter->hw;
> +	u32 reg_data;
> +
> +	hw->loopback_on = on;
> +	/* Setup MAC loopback */
> +	reg_data = IXGBE_READ_REG(hw, IXGBE_HLREG0);
> +	if (on)
> +		reg_data |= IXGBE_HLREG0_LPBK;
> +	else
> +		reg_data &= ~IXGBE_HLREG0_LPBK;
> +	IXGBE_WRITE_REG(hw, IXGBE_HLREG0, reg_data);
> +
> +	reg_data = IXGBE_READ_REG(hw, IXGBE_FCTRL);
> +	if (on)
> +		reg_data |= IXGBE_FCTRL_SBP | IXGBE_FCTRL_MPE;
> +	else
> +		reg_data &= ~(IXGBE_FCTRL_SBP | IXGBE_FCTRL_MPE);
> +	reg_data &= ~(IXGBE_FCTRL_BAM);
> +	IXGBE_WRITE_REG(hw, IXGBE_FCTRL, reg_data);
> +
> +	/* X540 and X550 needs to set the MACC.FLU bit to force link up */
> +	switch (adapter->hw.mac.type) {
> +	case ixgbe_mac_X540:
> +	case ixgbe_mac_X550:
> +	case ixgbe_mac_X550EM_x:
> +	case ixgbe_mac_x550em_a:
> +		reg_data = IXGBE_READ_REG(hw, IXGBE_MACC);
> +		if (on)
> +			reg_data |= IXGBE_MACC_FLU;
> +		else
> +			reg_data &= ~IXGBE_MACC_FLU;
> +		IXGBE_WRITE_REG(hw, IXGBE_MACC, reg_data);
> +		break;
> +	default:
> +		if (hw->mac.orig_autoc) {
> +			if (on)
> +				reg_data = hw->mac.orig_autoc | IXGBE_AUTOC_FLU;
> +			else
> +				reg_data = hw->mac.orig_autoc & ~IXGBE_AUTOC_FLU;
> +			IXGBE_WRITE_REG(hw, IXGBE_AUTOC, reg_data);
> +		} else {
> +			return 10;
> +		}
> +	}
> +
> +	IXGBE_WRITE_FLUSH(hw);
> +
> +	return 0;
> +}
> +
>  static netdev_tx_t __ixgbe_xmit_frame(struct sk_buff *skb,
>  				      struct net_device *netdev,
>  				      struct ixgbe_ring *ring)
> @@ -9923,6 +9974,15 @@ static int ixgbe_set_features(struct net_device *netdev,
>  	if (changed & NETIF_F_RXALL)
>  		need_reset = true;
>  
> +	if (changed & NETIF_F_LOOPBACK) {
> +		if (features & NETIF_F_LOOPBACK) {
> +			ixgbe_force_loopback(adapter, true);
> +		} else {
> +			ixgbe_force_loopback(adapter, false);
> +			need_reset = true;
> +			}
> +	}
> +
>  	netdev->features = features;
>  
>  	if ((changed & NETIF_F_HW_L2FW_DOFFLOAD) && adapter->num_rx_pools > 1)
> @@ -10296,6 +10356,17 @@ static int ixgbe_xdp_setup(struct net_device *dev, struct bpf_prog *prog)
>  			/* Wait until ndo_xsk_wakeup completes. */
>  			synchronize_rcu();
>  		err = ixgbe_setup_tc(dev, adapter->hw_tcs);
> +		if (adapter->hw.loopback_on) {
> +			u32 reg_data;
> +
> +			reg_data = IXGBE_READ_REG(&adapter->hw, IXGBE_HLREG0);
> +			reg_data |= IXGBE_HLREG0_LPBK;
> +			IXGBE_WRITE_REG(&adapter->hw, IXGBE_HLREG0, reg_data);
> +
> +			reg_data = IXGBE_READ_REG(&adapter->hw, IXGBE_MACC);
> +			reg_data |= IXGBE_MACC_FLU;
> +			IXGBE_WRITE_REG(&adapter->hw, IXGBE_MACC, reg_data);
> +		}
>  
>  		if (err) {
>  			rcu_assign_pointer(adapter->xdp_prog, old_prog);
> @@ -10979,6 +11050,8 @@ static int ixgbe_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>  	if (hw->mac.type >= ixgbe_mac_82599EB)
>  		netdev->features |= NETIF_F_SCTP_CRC | NETIF_F_GSO_UDP_L4;
>  
> +	netdev->features |= NETIF_F_LOOPBACK;
> +
>  #ifdef CONFIG_IXGBE_IPSEC
>  #define IXGBE_ESP_FEATURES	(NETIF_F_HW_ESP | \
>  				 NETIF_F_HW_ESP_TX_CSUM | \
> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_type.h b/drivers/net/ethernet/intel/ixgbe/ixgbe_type.h
> index 2b00db92b08f..ca50ccd59b50 100644
> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_type.h
> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_type.h
> @@ -3652,6 +3652,7 @@ struct ixgbe_hw {
>  	bool				allow_unsupported_sfp;
>  	bool				wol_enabled;
>  	bool				need_crosstalk_fix;
> +	bool				loopback_on;
>  };
>  
>  struct ixgbe_info {
> -- 
> 2.34.1
>