Subject: Re: [PATCH net-next v1 1/1] net: dsa: microchip: ksz8: Make flow control, speed, and duplex on CPU port configurable

From: Jakub Kicinski <[email-masked]>
Date: Thu, 6 Apr 2023 19:04:04 -0700

On Tue,  4 Apr 2023 12:12:25 +0200 Oleksij Rempel wrote:
> Allow flow control, speed, and duplex settings on the CPU port to be
> configurable. Previously, the speed and duplex relied on default switch
> values, which limited flexibility. Additionally, flow control was
> hardcoded and only functional in duplex mode. This update enhances the
> configurability of these parameters.

Anyone who knows DSA/phylink willing to venture a review tag? :)

> diff --git a/drivers/net/dsa/microchip/ksz8.h b/drivers/net/dsa/microchip/ksz8.h
> index ea05abfbd51d..9bb19764fa33 100644
> --- a/drivers/net/dsa/microchip/ksz8.h
> +++ b/drivers/net/dsa/microchip/ksz8.h
> @@ -58,5 +58,9 @@ int ksz8_switch_detect(struct ksz_device *dev);
>  int ksz8_switch_init(struct ksz_device *dev);
>  void ksz8_switch_exit(struct ksz_device *dev);
>  int ksz8_change_mtu(struct ksz_device *dev, int port, int mtu);
> +void ksz8_phylink_mac_link_up(struct ksz_device *dev, int port,
> +			      unsigned int mode, phy_interface_t interface,
> +			      struct phy_device *phydev, int speed, int duplex,
> +			      bool tx_pause, bool rx_pause);
>  
>  #endif
> diff --git a/drivers/net/dsa/microchip/ksz8795.c b/drivers/net/dsa/microchip/ksz8795.c
> index d0e3f6e2db1d..8917f22f90d2 100644
> --- a/drivers/net/dsa/microchip/ksz8795.c
> +++ b/drivers/net/dsa/microchip/ksz8795.c
> @@ -1321,12 +1321,52 @@ void ksz8_config_cpu_port(struct dsa_switch *ds)
>  			if (remote & KSZ8_PORT_FIBER_MODE)
>  				p->fiber = 1;
>  		}
> -		if (p->fiber)
> -			ksz_port_cfg(dev, i, regs[P_STP_CTRL],
> -				     PORT_FORCE_FLOW_CTRL, true);
> -		else
> -			ksz_port_cfg(dev, i, regs[P_STP_CTRL],
> -				     PORT_FORCE_FLOW_CTRL, false);
> +	}
> +}
> +
> +void ksz8_phylink_mac_link_up(struct ksz_device *dev, int port,
> +			      unsigned int mode, phy_interface_t interface,
> +			      struct phy_device *phydev, int speed, int duplex,
> +			      bool tx_pause, bool rx_pause)
> +{
> +	struct dsa_switch *ds = dev->ds;
> +	struct ksz_port *p;
> +	u8 ctrl = 0;
> +
> +	p = &dev->ports[port];
> +
> +	if (dsa_upstream_port(ds, port)) {
> +		u8 mask = SW_HALF_DUPLEX_FLOW_CTRL | SW_HALF_DUPLEX |
> +			SW_FLOW_CTRL | SW_10_MBIT;
> +
> +		if (duplex) {
> +			if (tx_pause && rx_pause)
> +				ctrl |= SW_FLOW_CTRL;
> +		} else {
> +			ctrl |= SW_HALF_DUPLEX;
> +			if (tx_pause && rx_pause)
> +				ctrl |= SW_HALF_DUPLEX_FLOW_CTRL;
> +		}
> +
> +		if (speed == SPEED_10)
> +			ctrl |= SW_10_MBIT;
> +
> +		ksz_rmw8(dev, REG_SW_CTRL_4, mask, ctrl);
> +
> +		p->phydev.speed = speed;
> +	} else {
> +		const u16 *regs = dev->info->regs;
> +
> +		if (duplex) {
> +			if (tx_pause && rx_pause)
> +				ctrl |= PORT_FORCE_FLOW_CTRL;
> +		} else {
> +			if (tx_pause && rx_pause)
> +				ctrl |= PORT_BACK_PRESSURE;
> +		}
> +
> +		ksz_rmw8(dev, regs[P_STP_CTRL], PORT_FORCE_FLOW_CTRL |
> +			 PORT_BACK_PRESSURE, ctrl);
>  	}
>  }
>  
> @@ -1380,8 +1420,6 @@ int ksz8_setup(struct dsa_switch *ds)
>  	 */
>  	ds->vlan_filtering_is_global = true;
>  
> -	ksz_cfg(dev, S_REPLACE_VID_CTRL, SW_FLOW_CTRL, true);
> -
>  	/* Enable automatic fast aging when link changed detected. */
>  	ksz_cfg(dev, S_LINK_AGING_CTRL, SW_LINK_AUTO_AGING, true);
>  
> diff --git a/drivers/net/dsa/microchip/ksz_common.c b/drivers/net/dsa/microchip/ksz_common.c
> index 5568d7b22135..93131347ad98 100644
> --- a/drivers/net/dsa/microchip/ksz_common.c
> +++ b/drivers/net/dsa/microchip/ksz_common.c
> @@ -208,6 +208,7 @@ static const struct ksz_dev_ops ksz8_dev_ops = {
>  	.mirror_add = ksz8_port_mirror_add,
>  	.mirror_del = ksz8_port_mirror_del,
>  	.get_caps = ksz8_get_caps,
> +	.phylink_mac_link_up = ksz8_phylink_mac_link_up,
>  	.config_cpu_port = ksz8_config_cpu_port,
>  	.enable_stp_addr = ksz8_enable_stp_addr,
>  	.reset = ksz8_reset_switch,