Re: [net-next PATCH v4 06/13] net: dsa: qca8k: move rgmii delay detection to phylink mac_config

[Ansuel Smith <ansuelsmth@gmail.com>]

On Sun, Oct 10, 2021 at 03:47:32PM +0300, Vladimir Oltean wrote:
> On Sun, Oct 10, 2021 at 01:15:49PM +0200, Ansuel Smith wrote:
> > Future proof commit. This switch have 2 CPU port and one valid
> > configuration is first CPU port set to sgmii and second CPU port set to
> > regmii-id. The current implementation detects delay only for CPU port
> > zero set to rgmii and doesn't count any delay set in a secondary CPU
> > port. Drop the current delay scan function and move it to the phylink
> > mac_config to generilize and implicitly add support for secondary CPU
> > port set to rgmii-id.
> > 
> > Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
> > ---
> >  drivers/net/dsa/qca8k.c | 121 +++++++++++++++-------------------------
> >  drivers/net/dsa/qca8k.h |   2 -
> >  2 files changed, 44 insertions(+), 79 deletions(-)
> > 
> > diff --git a/drivers/net/dsa/qca8k.c b/drivers/net/dsa/qca8k.c
> > index df0a622acdd7..126f20b0b94c 100644
> > --- a/drivers/net/dsa/qca8k.c
> > +++ b/drivers/net/dsa/qca8k.c
> > @@ -888,68 +888,6 @@ qca8k_setup_mdio_bus(struct qca8k_priv *priv)
> >  	return 0;
> >  }
> >  
> > -static int
> > -qca8k_setup_of_rgmii_delay(struct qca8k_priv *priv)
> 
> I was actually going to say that since RGMII delays are runtime
> invariants, you should move their entire programming to probe time, now
> you move device tree parsing to runtime :-/
> 

The main idea here was to move everything to mac config and scan the DT
node of the current port that is being configured. 

> > -{
> > -	struct device_node *port_dn;
> > -	phy_interface_t mode;
> > -	struct dsa_port *dp;
> > -	u32 val;
> > -
> > -	/* CPU port is already checked */
> > -	dp = dsa_to_port(priv->ds, 0);
> > -
> > -	port_dn = dp->dn;
> > -
> > -	/* Check if port 0 is set to the correct type */
> > -	of_get_phy_mode(port_dn, &mode);
> > -	if (mode != PHY_INTERFACE_MODE_RGMII_ID &&
> > -	    mode != PHY_INTERFACE_MODE_RGMII_RXID &&
> > -	    mode != PHY_INTERFACE_MODE_RGMII_TXID) {
> > -		return 0;
> > -	}
> > -
> > -	switch (mode) {
> > -	case PHY_INTERFACE_MODE_RGMII_ID:
> > -	case PHY_INTERFACE_MODE_RGMII_RXID:
> 
> Also, since you touch this area.
> There have been tons of discussions on this topic, but I believe that
> your interpretation of the RGMII delays is wrong.
> Basically a MAC should not apply delays based on the phy-mode string (so
> it should treat "rgmii" same as "rgmii-id"), but based on the value of
> "rx-internal-delay-ps" and "tx-internal-delay-ps".
> The phy-mode is for a PHY to use.
>

Ok so we can just drop the case and directly check for the
internal-delay-ps presence?

> > -		if (of_property_read_u32(port_dn, "rx-internal-delay-ps", &val))
> > -			val = 2;
> > -		else
> > -			/* Switch regs accept value in ns, convert ps to ns */
> > -			val = val / 1000;
> > -
> > -		if (val > QCA8K_MAX_DELAY) {
> > -			dev_err(priv->dev, "rgmii rx delay is limited to a max value of 3ns, setting to the max value");
> > -			val = 3;
> > -		}
> > -
> > -		priv->rgmii_rx_delay = val;
> > -		/* Stop here if we need to check only for rx delay */
> > -		if (mode != PHY_INTERFACE_MODE_RGMII_ID)
> > -			break;
> > -
> > -		fallthrough;
> > -	case PHY_INTERFACE_MODE_RGMII_TXID:
> > -		if (of_property_read_u32(port_dn, "tx-internal-delay-ps", &val))
> > -			val = 1;
> > -		else
> > -			/* Switch regs accept value in ns, convert ps to ns */
> > -			val = val / 1000;
> > -
> > -		if (val > QCA8K_MAX_DELAY) {
> > -			dev_err(priv->dev, "rgmii tx delay is limited to a max value of 3ns, setting to the max value");
> > -			val = 3;
> > -		}
> > -
> > -		priv->rgmii_tx_delay = val;
> > -		break;
> > -	default:
> > -		return 0;
> > -	}
> > -
> > -	return 0;
> > -}
> > -
> >  static int
> >  qca8k_setup_mac_pwr_sel(struct qca8k_priv *priv)
> >  {
> > @@ -1019,10 +957,6 @@ qca8k_setup(struct dsa_switch *ds)
> >  	if (ret)
> >  		return ret;
> >  
> > -	ret = qca8k_setup_of_rgmii_delay(priv);
> > -	if (ret)
> > -		return ret;
> > -
> >  	ret = qca8k_setup_mac_pwr_sel(priv);
> >  	if (ret)
> >  		return ret;
> > @@ -1190,7 +1124,7 @@ qca8k_phylink_mac_config(struct dsa_switch *ds, int port, unsigned int mode,
> >  {
> >  	struct qca8k_priv *priv = ds->priv;
> >  	struct dsa_port *dp;
> > -	u32 reg, val;
> > +	u32 reg, val, delay;
> >  	int ret;
> >  
> >  	switch (port) {
> > @@ -1241,17 +1175,50 @@ qca8k_phylink_mac_config(struct dsa_switch *ds, int port, unsigned int mode,
> >  	case PHY_INTERFACE_MODE_RGMII_ID:
> >  	case PHY_INTERFACE_MODE_RGMII_TXID:
> >  	case PHY_INTERFACE_MODE_RGMII_RXID:
> > -		/* RGMII_ID needs internal delay. This is enabled through
> > -		 * PORT5_PAD_CTRL for all ports, rather than individual port
> > -		 * registers
> > +		dp = dsa_to_port(ds, port);
> > +		val = QCA8K_PORT_PAD_RGMII_EN;
> > +
> > +		if (state->interface == PHY_INTERFACE_MODE_RGMII_ID ||
> > +		    state->interface == PHY_INTERFACE_MODE_RGMII_TXID) {
> > +			if (of_property_read_u32(dp->dn, "tx-internal-delay-ps", &delay))
> > +				delay = 1;
> > +			else
> > +				/* Switch regs accept value in ns, convert ps to ns */
> > +				delay = delay / 1000;
> > +
> > +			if (delay > QCA8K_MAX_DELAY) {
> > +				dev_err(priv->dev, "rgmii tx delay is limited to a max value of 3ns, setting to the max value");
> > +				delay = 3;
> > +			}
> > +
> > +			val |= QCA8K_PORT_PAD_RGMII_TX_DELAY(delay) |
> > +			       QCA8K_PORT_PAD_RGMII_TX_DELAY_EN;
> > +		}
> > +
> > +		if (state->interface == PHY_INTERFACE_MODE_RGMII_ID ||
> > +		    state->interface == PHY_INTERFACE_MODE_RGMII_RXID) {
> > +			if (of_property_read_u32(dp->dn, "rx-internal-delay-ps", &delay))
> > +				delay = 2;
> > +			else
> > +				/* Switch regs accept value in ns, convert ps to ns */
> > +				delay = delay / 1000;
> > +
> > +			if (delay > QCA8K_MAX_DELAY) {
> > +				dev_err(priv->dev, "rgmii rx delay is limited to a max value of 3ns, setting to the max value");
> > +				delay = 3;
> > +			}
> > +
> > +			val |= QCA8K_PORT_PAD_RGMII_RX_DELAY(delay) |
> > +			       QCA8K_PORT_PAD_RGMII_RX_DELAY_EN;
> > +		}
> > +
> > +		/* Set RGMII delay based on the selected values */
> > +		qca8k_write(priv, reg, val);
> > +
> > +		/* QCA8337 requires to set rgmii rx delay for all ports.
> > +		 * This is enabled through PORT5_PAD_CTRL for all ports,
> > +		 * rather than individual port registers.
> >  		 */
> > -		qca8k_write(priv, reg,
> > -			    QCA8K_PORT_PAD_RGMII_EN |
> > -			    QCA8K_PORT_PAD_RGMII_TX_DELAY(priv->rgmii_tx_delay) |
> > -			    QCA8K_PORT_PAD_RGMII_RX_DELAY(priv->rgmii_rx_delay) |
> > -			    QCA8K_PORT_PAD_RGMII_TX_DELAY_EN |
> > -			    QCA8K_PORT_PAD_RGMII_RX_DELAY_EN);
> > -		/* QCA8337 requires to set rgmii rx delay */
> >  		if (priv->switch_id == QCA8K_ID_QCA8337)
> >  			qca8k_write(priv, QCA8K_REG_PORT5_PAD_CTRL,
> >  				    QCA8K_PORT_PAD_RGMII_RX_DELAY_EN);
> > diff --git a/drivers/net/dsa/qca8k.h b/drivers/net/dsa/qca8k.h
> > index 5df0f0ef6526..a790b27bc310 100644
> > --- a/drivers/net/dsa/qca8k.h
> > +++ b/drivers/net/dsa/qca8k.h
> > @@ -259,8 +259,6 @@ struct qca8k_match_data {
> >  struct qca8k_priv {
> >  	u8 switch_id;
> >  	u8 switch_revision;
> > -	u8 rgmii_tx_delay;
> > -	u8 rgmii_rx_delay;
> >  	bool legacy_phy_port_mapping;
> >  	struct regmap *regmap;
> >  	struct mii_bus *bus;
> > -- 
> > 2.32.0
> > 
> 

-- 
	Ansuel