net: dsa: bcm_sf2: setup BCM4908 internal crossbar

On some SoCs (e.g. BCM4908, BCM631[345]8) SF2 has an integrated
crossbar. It allows connecting its selected external ports to internal
ports. It's used by vendors to handle custom Ethernet setups.

BCM4908 has following 3x2 crossbar. On Asus GT-AC5300 rgmii is used for
connecting external BCM53134S switch. GPHY4 is usually used for WAN
port. More fancy devices use SerDes for 2.5 Gbps Ethernet.

              ┌──────────┐
SerDes ─── 0 ─┤          │
              │   3x2    ├─ 0 ─── switch port 7
 GPHY4 ─── 1 ─┤          │
              │ crossbar ├─ 1 ─── runner (accelerator)
 rgmii ─── 2 ─┤          │
              └──────────┘

Use setup data based on DT info to configure BCM4908's switch port 7.
Right now only GPHY and rgmii variants are supported. Handling SerDes
can be implemented later.
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/bcm_sf2.c

@@ -432,6 +432,44 @@ static int bcm_sf2_sw_rst(struct bcm_sf2_priv *priv)
 	return 0;
 }
 
+static void bcm_sf2_crossbar_setup(struct bcm_sf2_priv *priv)
+{
+	struct device *dev = priv->dev->ds->dev;
+	int shift;
+	u32 mask;
+	u32 reg;
+	int i;
+
+	mask = BIT(priv->num_crossbar_int_ports) - 1;
+
+	reg = reg_readl(priv, REG_CROSSBAR);
+	switch (priv->type) {
+	case BCM4908_DEVICE_ID:
+		shift = CROSSBAR_BCM4908_INT_P7 * priv->num_crossbar_int_ports;
+		reg &= ~(mask << shift);
+		if (0) /* FIXME */
+			reg |= CROSSBAR_BCM4908_EXT_SERDES << shift;
+		else if (priv->int_phy_mask & BIT(7))
+			reg |= CROSSBAR_BCM4908_EXT_GPHY4 << shift;
+		else if (phy_interface_mode_is_rgmii(priv->port_sts[7].mode))
+			reg |= CROSSBAR_BCM4908_EXT_RGMII << shift;
+		else if (WARN(1, "Invalid port mode\n"))
+			return;
+		break;
+	default:
+		return;
+	}
+	reg_writel(priv, reg, REG_CROSSBAR);
+
+	reg = reg_readl(priv, REG_CROSSBAR);
+	for (i = 0; i < priv->num_crossbar_int_ports; i++) {
+		shift = i * priv->num_crossbar_int_ports;
+
+		dev_dbg(dev, "crossbar int port #%d - ext port #%d\n", i,
+			(reg >> shift) & mask);
+	}
+}
+
 static void bcm_sf2_intr_disable(struct bcm_sf2_priv *priv)
 {
 	intrl2_0_mask_set(priv, 0xffffffff);
@@ -864,6 +902,8 @@ static int bcm_sf2_sw_resume(struct dsa_switch *ds)
 		return ret;
 	}
 
+	bcm_sf2_crossbar_setup(priv);
+
 	ret = bcm_sf2_cfp_resume(ds);
 	if (ret)
 		return ret;
@@ -1136,6 +1176,7 @@ struct bcm_sf2_of_data {
 	const u16 *reg_offsets;
 	unsigned int core_reg_align;
 	unsigned int num_cfp_rules;
+	unsigned int num_crossbar_int_ports;
 };
 
 static const u16 bcm_sf2_4908_reg_offsets[] = {
@@ -1160,6 +1201,7 @@ static const struct bcm_sf2_of_data bcm_sf2_4908_data = {
 	.core_reg_align	= 0,
 	.reg_offsets	= bcm_sf2_4908_reg_offsets,
 	.num_cfp_rules	= 0, /* FIXME */
+	.num_crossbar_int_ports = 2,
 };
 
 /* Register offsets for the SWITCH_REG_* block */
@@ -1270,6 +1312,7 @@ static int bcm_sf2_sw_probe(struct platform_device *pdev)
 	priv->reg_offsets = data->reg_offsets;
 	priv->core_reg_align = data->core_reg_align;
 	priv->num_cfp_rules = data->num_cfp_rules;
+	priv->num_crossbar_int_ports = data->num_crossbar_int_ports;
 
 	priv->rcdev = devm_reset_control_get_optional_exclusive(&pdev->dev,
 								"switch");
@@ -1343,6 +1386,8 @@ static int bcm_sf2_sw_probe(struct platform_device *pdev)
 		goto out_clk_mdiv;
 	}
 
+	bcm_sf2_crossbar_setup(priv);
+
 	bcm_sf2_gphy_enable_set(priv->dev->ds, true);
 
 	ret = bcm_sf2_mdio_register(ds);

drivers/net/dsa/bcm_sf2.h

@@ -74,6 +74,7 @@ struct bcm_sf2_priv {
 	const u16			*reg_offsets;
 	unsigned int			core_reg_align;
 	unsigned int			num_cfp_rules;
+	unsigned int			num_crossbar_int_ports;
 
 	/* spinlock protecting access to the indirect registers */
 	spinlock_t			indir_lock;

drivers/net/dsa/bcm_sf2_regs.h

@@ -48,6 +48,13 @@ enum bcm_sf2_reg_offs {
 #define  PHY_PHYAD_SHIFT		8
 #define  PHY_PHYAD_MASK			0x1F
 
+/* Relative to REG_CROSSBAR */
+#define CROSSBAR_BCM4908_INT_P7		0
+#define CROSSBAR_BCM4908_INT_RUNNER	1
+#define CROSSBAR_BCM4908_EXT_SERDES	0
+#define CROSSBAR_BCM4908_EXT_GPHY4	1
+#define CROSSBAR_BCM4908_EXT_RGMII	2
+
 #define REG_RGMII_CNTRL_P(x)		(REG_RGMII_0_CNTRL + (x))
 
 /* Relative to REG_RGMII_CNTRL */