drivers: net: stmmac: add port selection programming

In case of SGMII more, for example when a MAC2MAC connection
is needed, the port selection bits (inside the MAC configuration
registers) have to be programmed according to the link selected.
So the patch adds a new DT parameter to pass the port selection
and to programmed related PCS and CORE to use it.

Signed-off-by: Giuseppe Cavallaro <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

Documentation/devicetree/bindings/net/stmmac.txt

···
 				supported by this device instance
 - snps,perfect-filter-entries:	Number of perfect filter entries supported
 				by this device instance
+- snps,ps-speed: port selection speed that can be passed to the core when
+		 PCS is supported. For example, this is used in case of SGMII
+		 and MAC2MAC connection.
 - AXI BUS Mode parameters: below the list of all the parameters to program the
 			   AXI register inside the DMA module:
 	- snps,lpi_en: enable Low Power Interface

drivers/net/ethernet/stmicro/stmmac/common.h

···
 	unsigned int rx_csum;
 	unsigned int pcs;
 	unsigned int pmt;
+	unsigned int ps;
 };
 
 struct mac_device_info *dwmac1000_setup(void __iomem *ioaddr, int mcbins,

drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c

···
 	if (mtu > 2000)
 		value |= GMAC_CONTROL_JE;
 
+	if (hw->ps) {
+		value |= GMAC_CONTROL_TE;
+
+		if (hw->ps == SPEED_1000) {
+			value &= ~GMAC_CONTROL_PS;
+		} else {
+			value |= GMAC_CONTROL_PS;
+
+			if (hw->ps == SPEED_10)
+				value &= ~GMAC_CONTROL_FES;
+			else
+				value |= GMAC_CONTROL_FES;
+		}
+	}
+
 	writel(value, ioaddr + GMAC_CONTROL);
 
 	/* Mask GMAC interrupts */

drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c

···
 	if (mtu > 2000)
 		value |= GMAC_CONFIG_JE;
 
+	if (hw->ps) {
+		value |= GMAC_CONFIG_TE;
+
+		if (hw->ps == SPEED_1000) {
+			value &= ~GMAC_CONFIG_PS;
+		} else {
+			value |= GMAC_CONFIG_PS;
+
+			if (hw->ps == SPEED_10)
+				value &= ~GMAC_CONFIG_FES;
+			else
+				value |= GMAC_CONFIG_FES;
+		}
+	}
+
 	writel(value, ioaddr + GMAC_CONFIG);
 
 	/* Mask GMAC interrupts */

drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c

···
 		spin_lock(&priv->lock);
 
 		if (priv->hw->mac->pcs_ctrl_ane)
-			priv->hw->mac->pcs_ctrl_ane(priv->ioaddr, 1, 0, 0);
+			priv->hw->mac->pcs_ctrl_ane(priv->ioaddr, 1,
+						    priv->hw->ps, 0);
 
 		spin_unlock(&priv->lock);
 

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

···
 	if (priv->plat->bus_setup)
 		priv->plat->bus_setup(priv->ioaddr);
 
+	/* PS and related bits will be programmed according to the speed */
+	if (priv->hw->pcs) {
+		int speed = priv->plat->mac_port_sel_speed;
+
+		if ((speed == SPEED_10) || (speed == SPEED_100) ||
+		    (speed == SPEED_1000)) {
+			priv->hw->ps = speed;
+		} else {
+			dev_warn(priv->device, "invalid port speed\n");
+			priv->hw->ps = 0;
+		}
+	}
+
 	/* Initialize the MAC Core */
 	priv->hw->mac->core_init(priv->hw, dev->mtu);
 
···
 	}
 
 	if (priv->hw->pcs && priv->hw->mac->pcs_ctrl_ane)
-		priv->hw->mac->pcs_ctrl_ane(priv->hw, 1, 0, 0);
+		priv->hw->mac->pcs_ctrl_ane(priv->hw, 1, priv->hw->ps, 0);
 
 	/*  set TX ring length */
 	if (priv->hw->dma->set_tx_ring_len)

drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c

···
 		pr_warn("force_sf_dma_mode is ignored if force_thresh_dma_mode is set.");
 	}
 
+	of_property_read_u32(np, "snps,ps-speed", &plat->mac_port_sel_speed);
+
 	plat->axi = stmmac_axi_setup(pdev);
 
 	return plat;

include/linux/stmmac.h

···
 	struct stmmac_axi *axi;
 	int has_gmac4;
 	bool tso_en;
+	int mac_port_sel_speed;
 };
 #endif