Subject: Re: [PATCH net-next 11/12] net: airoha: Refactor src port configuration in airhoha_set_gdm2_loopback

From: Simon Horman <[email-masked]>
Date: Wed, 15 Oct 2025 17:05:12 +0100

On Wed, Oct 15, 2025 at 09:15:11AM +0200, Lorenzo Bianconi wrote:
> AN7583 chipset relies on different definitions for source-port
> identifier used for hw offloading. In order to support hw offloading
> in AN7583 controller, refactor src port configuration in
> airhoha_set_gdm2_loopback routine and introduce get_src_port_id
> callback.
> 
> Signed-off-by: Lorenzo Bianconi <[email-masked]>
> ---
>  drivers/net/ethernet/airoha/airoha_eth.c  | 75 +++++++++++++++++++++----------
>  drivers/net/ethernet/airoha/airoha_eth.h  | 11 +++--
>  drivers/net/ethernet/airoha/airoha_regs.h |  5 +--
>  3 files changed, 60 insertions(+), 31 deletions(-)
> 
> diff --git a/drivers/net/ethernet/airoha/airoha_eth.c b/drivers/net/ethernet/airoha/airoha_eth.c
> index 5f6b5ab52e0265f7bb56b008ca653d64e04ff2d2..76c82750b3ae89a9fa81c64d3b7c3578b369480c 100644
> --- a/drivers/net/ethernet/airoha/airoha_eth.c
> +++ b/drivers/net/ethernet/airoha/airoha_eth.c
> @@ -1682,11 +1682,14 @@ static int airoha_dev_set_macaddr(struct net_device *dev, void *p)
>  	return 0;
>  }
>  
> -static void airhoha_set_gdm2_loopback(struct airoha_gdm_port *port)
> +static int airhoha_set_gdm2_loopback(struct airoha_gdm_port *port)
>  {
>  	u32 pse_port = port->id == 3 ? FE_PSE_PORT_GDM3 : FE_PSE_PORT_GDM4;
>  	struct airoha_eth *eth = port->qdma->eth;
>  	u32 chan = port->id == 3 ? 4 : 0;
> +	/* XXX: handle XSI_USB_PORT and XSI_PCE1_PORT */
> +	u32 nbq = port->id == 3 ? 4 : 0;
> +	int src_port;

I think this code could benefit for names (defines) for port ids.
It's a bit clearer in airoha_en7581_get_src_port_id(). But the
numbers seem kind of magic in this function.

>  
>  	/* Forward the traffic to the proper GDM port */
>  	airoha_set_gdm_port_fwd_cfg(eth, REG_GDM_FWD_CFG(2), pse_port);
> @@ -1709,29 +1712,23 @@ static void airhoha_set_gdm2_loopback(struct airoha_gdm_port *port)
>  	airoha_fe_clear(eth, REG_FE_VIP_PORT_EN, BIT(2));
>  	airoha_fe_clear(eth, REG_FE_IFC_PORT_EN, BIT(2));
>  
> -	if (port->id == 3) {
> -		/* FIXME: handle XSI_PCE1_PORT */
> -		airoha_fe_rmw(eth, REG_FE_WAN_PORT,
> -			      WAN1_EN_MASK | WAN1_MASK | WAN0_MASK,
> -			      FIELD_PREP(WAN0_MASK, HSGMII_LAN_PCIE0_SRCPORT));
> -		airoha_fe_rmw(eth,
> -			      REG_SP_DFT_CPORT(HSGMII_LAN_PCIE0_SRCPORT >> 3),
> -			      SP_CPORT_PCIE0_MASK,
> -			      FIELD_PREP(SP_CPORT_PCIE0_MASK,
> -					 FE_PSE_PORT_CDM2));
> -	} else {
> -		/* FIXME: handle XSI_USB_PORT */
> +	src_port = eth->soc->ops.get_src_port_id(port, nbq);
> +	if (src_port < 0)
> +		return src_port;
> +
> +	airoha_fe_rmw(eth, REG_FE_WAN_PORT,
> +		      WAN1_EN_MASK | WAN1_MASK | WAN0_MASK,
> +		      FIELD_PREP(WAN0_MASK, src_port));
> +	airoha_fe_rmw(eth, REG_SP_DFT_CPORT(src_port >> 3),
> +		      SP_CPORT_MASK(src_port & 0x7),
> +		      FE_PSE_PORT_CDM2 << __ffs(SP_CPORT_MASK(src_port & 0x7)));

Likewise, 3 and 0x7 a bit magical here.

> +
> +	if (port->id != 3)
>  		airoha_fe_rmw(eth, REG_SRC_PORT_FC_MAP6,
>  			      FC_ID_OF_SRC_PORT24_MASK,
>  			      FIELD_PREP(FC_ID_OF_SRC_PORT24_MASK, 2));

... and 2 here.

> -		airoha_fe_rmw(eth, REG_FE_WAN_PORT,
> -			      WAN1_EN_MASK | WAN1_MASK | WAN0_MASK,
> -			      FIELD_PREP(WAN0_MASK, HSGMII_LAN_ETH_SRCPORT));
> -		airoha_fe_rmw(eth,
> -			      REG_SP_DFT_CPORT(HSGMII_LAN_ETH_SRCPORT >> 3),
> -			      SP_CPORT_ETH_MASK,
> -			      FIELD_PREP(SP_CPORT_ETH_MASK, FE_PSE_PORT_CDM2));
> -	}
> +
> +	return 0;
>  }

...

> @@ -3055,11 +3057,38 @@ static const char * const en7581_xsi_rsts_names[] = {
>  	"xfp-mac",
>  };
>  
> +static int airoha_en7581_get_src_port_id(struct airoha_gdm_port *port, int nbq)
> +{
> +	switch (port->id) {
> +	case 3:
> +		/* 7581 SoC supports PCIe serdes on GDM3 port */
> +		if (nbq == 4)
> +			return HSGMII_LAN_7581_PCIE0_SRCPORT;
> +		if (nbq == 5)
> +			return HSGMII_LAN_7581_PCIE1_SRCPORT;
> +		break;
> +	case 4:
> +		/* 7581 SoC supports eth and usb serdes on GDM4 port */
> +		if (!nbq)
> +			return HSGMII_LAN_7581_ETH_SRCPORT;
> +		if (nbq == 1)
> +			return HSGMII_LAN_7581_USB_SRCPORT;
> +		break;
> +	default:
> +		break;
> +	}
> +
> +	return -EINVAL;
> +}

...