Re: [PATCH net-next v4 1/2] net: dsa: microchip: ksz8: Make flow control, speed, and duplex on CPU port configurable

Vladimir Oltean
2023-05-19T23:28:08Z

On Fri, May 19, 2023 at 02:46:59PM +0200, Oleksij Rempel wrote:
> diff --git a/drivers/net/dsa/microchip/ksz8795.c b/drivers/net/dsa/microchip/ksz8795.c
> index f56fca1b1a22..9eedccbf5b7c 100644
> --- a/drivers/net/dsa/microchip/ksz8795.c
> +++ b/drivers/net/dsa/microchip/ksz8795.c
> @@ -1371,6 +1371,57 @@ void ksz8_config_cpu_port(struct dsa_switch *ds)
> +/**
> + * ksz8_cpu_port_link_up - Configures the CPU port of the switch.
> + * @dev: The KSZ device instance.
> + * @speed: The desired link speed.
> + * @duplex: The desired duplex mode.
> + * @tx_pause: If true, enables transmit pause.
> + * @rx_pause: If true, enables receive pause.
> + *
> + * Description:
> + * The function configures flow control and speed settings for the CPU
> + * port of the switch based on the desired settings, current duplex mode, and
> + * speed.
> + */
> +static void ksz8_cpu_port_link_up(struct ksz_device *dev, int speed, int duplex,
> + bool tx_pause, bool rx_pause)
> +{
> + u8 ctrl = 0;
> +
> + /* SW_FLOW_CTRL, SW_HALF_DUPLEX, and SW_10_MBIT bits are bootstrappable
> + * at least on KSZ8873. They can have different values depending on your
> + * board setup.
> + */
> + if (duplex) {
> + if (tx_pause || rx_pause)
> + ctrl |= SW_FLOW_CTRL;
> + } else {
> + ctrl |= SW_HALF_DUPLEX;
> + }
> +
> + /* This hardware only supports SPEED_10 and SPEED_100. For SPEED_10
> + * we need to set the SW_10_MBIT bit. Otherwise, we can leave it 0.
> + */
> + if (speed == SPEED_10)
> + ctrl |= SW_10_MBIT;
> +
> + ksz_rmw8(dev, REG_SW_CTRL_4, SW_HALF_DUPLEX | SW_FLOW_CTRL |
> + SW_10_MBIT, ctrl);

REG_SW_CTRL_4 ... S_REPLACE_VID_CTRL ... dev->info->regs[P_XMII_CTRL_1] ...
at some point we will need one more consolidation effort here, since we
have at least 3 ways of reaching the same register.

> +}
> +
> +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)
> +{
> + /* If the port is the CPU port, apply special handling. Only the CPU
> + * port is configured via global registers.
> + */
> + if (dev->cpu_port == port)
> + ksz8_cpu_port_link_up(dev, speed, duplex, tx_pause, rx_pause);
> +}
> +
> static int ksz8_handle_global_errata(struct dsa_switch *ds)
> {
> struct ksz_device *dev = ds->priv;
> @@ -1419,8 +1470,6 @@ 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 a4428be5f483..6e19ad70c671 100644
> --- a/drivers/net/dsa/microchip/ksz_common.c
> +++ b/drivers/net/dsa/microchip/ksz_common.c
> @@ -210,6 +210,7 @@ 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,

Another future consolidation to consider: since all ksz_dev_ops now
provide .phylink_mac_link_up(), the "if" condition here is no longer
necessary:

static void ksz_phylink_mac_link_up(struct dsa_switch *ds, int port,
unsigned int mode,
phy_interface_t interface,
struct phy_device *phydev, int speed,
int duplex, bool tx_pause, bool rx_pause)
{
struct ksz_device *dev = ds->priv;

if (dev->dev_ops->phylink_mac_link_up)
dev->dev_ops->phylink_mac_link_up(dev, port, mode, interface,
phydev, speed, duplex,
tx_pause, rx_pause);
}

which reminds me of the fact that I also had a patch to remove
dev->dev_ops->phylink_mac_config():
https://patchwork.kernel.org/project/netdevbpf/patch/20230316161250.3286055-5-vladimir.oltean@nxp.com/

I give up with that patch set now, since there's zero reviewer interest.
If you want and you think it's useful, you might want to adapt it for
KSZ8873.

> .config_cpu_port = ksz8_config_cpu_port,
> .enable_stp_addr = ksz8_enable_stp_addr,
> .reset = ksz8_reset_switch,
> --
> 2.39.2
>

Reviewed-by: Vladimir Oltean <olteanv@gmail.com>