net: mediatek: split ethernet switch code from mtk_eth.c

mtk_eth.c contains not only the ethernet GMAC/DMA driver, but also
some ethernet switch initialization code. As we may add more switch
support in the future, it's better to move them out of mtk_eth.c to
avoid increasing the code complexity.

Since not all switches are supported for a particular board, Kconfig
options are added to allow user to select which switch should be
built into u-boot. If multiple switches are selected, auto-detecting
can also be enabled.

diff --git a/drivers/net/mtk_eth/mt7530.c b/drivers/net/mtk_eth/mt7530.c
new file mode 100644
index 0000000..3065d35
--- /dev/null
+++ b/drivers/net/mtk_eth/mt7530.c
@@ -0,0 +1,281 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2025 MediaTek Inc.
+ *
+ * Author: Weijie Gao <weijie.gao@mediatek.com>
+ * Author: Mark Lee <mark-mc.lee@mediatek.com>
+ */
+
+#include <miiphy.h>
+#include <linux/delay.h>
+#include <linux/mdio.h>
+#include <linux/mii.h>
+#include "mtk_eth.h"
+#include "mt753x.h"
+
+#define CHIP_REV			0x7ffc
+#define CHIP_NAME_S			16
+#define CHIP_NAME_M			0xffff0000
+#define CHIP_REV_S			0
+#define CHIP_REV_M			0x0f
+
+static void mt7530_core_reg_write(struct mt753x_switch_priv *priv, u32 reg,
+				  u32 val)
+{
+	u8 phy_addr = MT753X_PHY_ADDR(priv->phy_base, 0);
+
+	mtk_mmd_ind_write(priv->epriv.eth, phy_addr, 0x1f, reg, val);
+}
+
+static int mt7530_pad_clk_setup(struct mt753x_switch_priv *priv, int mode)
+{
+	u32 ncpo1, ssc_delta;
+
+	switch (mode) {
+	case PHY_INTERFACE_MODE_RGMII:
+		ncpo1 = 0x0c80;
+		ssc_delta = 0x87;
+		break;
+
+	default:
+		printf("error: xMII mode %d is not supported\n", mode);
+		return -EINVAL;
+	}
+
+	/* Disable MT7530 core clock */
+	mt7530_core_reg_write(priv, CORE_TRGMII_GSW_CLK_CG, 0);
+
+	/* Disable MT7530 PLL */
+	mt7530_core_reg_write(priv, CORE_GSWPLL_GRP1,
+			      (2 << RG_GSWPLL_POSDIV_200M_S) |
+			      (32 << RG_GSWPLL_FBKDIV_200M_S));
+
+	/* For MT7530 core clock = 500Mhz */
+	mt7530_core_reg_write(priv, CORE_GSWPLL_GRP2,
+			      (1 << RG_GSWPLL_POSDIV_500M_S) |
+			      (25 << RG_GSWPLL_FBKDIV_500M_S));
+
+	/* Enable MT7530 PLL */
+	mt7530_core_reg_write(priv, CORE_GSWPLL_GRP1,
+			      (2 << RG_GSWPLL_POSDIV_200M_S) |
+			      (32 << RG_GSWPLL_FBKDIV_200M_S) |
+			      RG_GSWPLL_EN_PRE);
+
+	udelay(20);
+
+	mt7530_core_reg_write(priv, CORE_TRGMII_GSW_CLK_CG, REG_GSWCK_EN);
+
+	/* Setup the MT7530 TRGMII Tx Clock */
+	mt7530_core_reg_write(priv, CORE_PLL_GROUP5, ncpo1);
+	mt7530_core_reg_write(priv, CORE_PLL_GROUP6, 0);
+	mt7530_core_reg_write(priv, CORE_PLL_GROUP10, ssc_delta);
+	mt7530_core_reg_write(priv, CORE_PLL_GROUP11, ssc_delta);
+	mt7530_core_reg_write(priv, CORE_PLL_GROUP4, RG_SYSPLL_DDSFBK_EN |
+			      RG_SYSPLL_BIAS_EN | RG_SYSPLL_BIAS_LPF_EN);
+
+	mt7530_core_reg_write(priv, CORE_PLL_GROUP2,
+			      RG_SYSPLL_EN_NORMAL | RG_SYSPLL_VODEN |
+			      (1 << RG_SYSPLL_POSDIV_S));
+
+	mt7530_core_reg_write(priv, CORE_PLL_GROUP7,
+			      RG_LCDDS_PCW_NCPO_CHG | (3 << RG_LCCDS_C_S) |
+			      RG_LCDDS_PWDB | RG_LCDDS_ISO_EN);
+
+	/* Enable MT7530 core clock */
+	mt7530_core_reg_write(priv, CORE_TRGMII_GSW_CLK_CG,
+			      REG_GSWCK_EN | REG_TRGMIICK_EN);
+
+	return 0;
+}
+
+static void mt7530_mac_control(struct mtk_eth_switch_priv *swpriv, bool enable)
+{
+	struct mt753x_switch_priv *priv = (struct mt753x_switch_priv *)swpriv;
+	u32 pmcr = FORCE_MODE;
+
+	if (enable)
+		pmcr = priv->pmcr;
+
+	mt753x_reg_write(priv, PMCR_REG(6), pmcr);
+}
+
+static int mt7530_mdio_read(struct mii_dev *bus, int addr, int devad, int reg)
+{
+	struct mt753x_switch_priv *priv = bus->priv;
+
+	if (devad < 0)
+		return mtk_mii_read(priv->epriv.eth, addr, reg);
+
+	return mtk_mmd_ind_read(priv->epriv.eth, addr, devad, reg);
+}
+
+static int mt7530_mdio_write(struct mii_dev *bus, int addr, int devad, int reg,
+			     u16 val)
+{
+	struct mt753x_switch_priv *priv = bus->priv;
+
+	if (devad < 0)
+		return mtk_mii_write(priv->epriv.eth, addr, reg, val);
+
+	return mtk_mmd_ind_write(priv->epriv.eth, addr, devad, reg, val);
+}
+
+static int mt7530_mdio_register(struct mt753x_switch_priv *priv)
+{
+	struct mii_dev *mdio_bus = mdio_alloc();
+	int ret;
+
+	if (!mdio_bus)
+		return -ENOMEM;
+
+	mdio_bus->read = mt7530_mdio_read;
+	mdio_bus->write = mt7530_mdio_write;
+	snprintf(mdio_bus->name, sizeof(mdio_bus->name), priv->epriv.sw->name);
+
+	mdio_bus->priv = priv;
+
+	ret = mdio_register(mdio_bus);
+	if (ret) {
+		mdio_free(mdio_bus);
+		return ret;
+	}
+
+	priv->mdio_bus = mdio_bus;
+
+	return 0;
+}
+
+static int mt7530_setup(struct mtk_eth_switch_priv *swpriv)
+{
+	struct mt753x_switch_priv *priv = (struct mt753x_switch_priv *)swpriv;
+	u16 phy_addr, phy_val;
+	u32 i, val, txdrv;
+
+	priv->smi_addr = MT753X_DFL_SMI_ADDR;
+	priv->reg_read = mt753x_mdio_reg_read;
+	priv->reg_write = mt753x_mdio_reg_write;
+
+	if (!MTK_HAS_CAPS(priv->epriv.soc->caps, MTK_TRGMII_MT7621_CLK)) {
+		/* Select 250MHz clk for RGMII mode */
+		mtk_ethsys_rmw(priv->epriv.eth, ETHSYS_CLKCFG0_REG,
+			       ETHSYS_TRGMII_CLK_SEL362_5, 0);
+
+		txdrv = 8;
+	} else {
+		txdrv = 4;
+	}
+
+	/* Modify HWTRAP first to allow direct access to internal PHYs */
+	mt753x_reg_read(priv, HWTRAP_REG, &val);
+	val |= CHG_TRAP;
+	val &= ~C_MDIO_BPS;
+	mt753x_reg_write(priv, MHWTRAP_REG, val);
+
+	/* Calculate the phy base address */
+	val = ((val & SMI_ADDR_M) >> SMI_ADDR_S) << 3;
+	priv->phy_base = (val | 0x7) + 1;
+
+	/* Turn off PHYs */
+	for (i = 0; i < MT753X_NUM_PHYS; i++) {
+		phy_addr = MT753X_PHY_ADDR(priv->phy_base, i);
+		phy_val = mtk_mii_read(priv->epriv.eth, phy_addr, MII_BMCR);
+		phy_val |= BMCR_PDOWN;
+		mtk_mii_write(priv->epriv.eth, phy_addr, MII_BMCR, phy_val);
+	}
+
+	/* Force MAC link down before reset */
+	mt753x_reg_write(priv, PMCR_REG(5), FORCE_MODE);
+	mt753x_reg_write(priv, PMCR_REG(6), FORCE_MODE);
+
+	/* MT7530 reset */
+	mt753x_reg_write(priv, SYS_CTRL_REG, SW_SYS_RST | SW_REG_RST);
+	udelay(100);
+
+	val = (IPG_96BIT_WITH_SHORT_IPG << IPG_CFG_S) |
+	      MAC_MODE | FORCE_MODE |
+	      MAC_TX_EN | MAC_RX_EN |
+	      BKOFF_EN | BACKPR_EN |
+	      (SPEED_1000M << FORCE_SPD_S) |
+	      FORCE_DPX | FORCE_LINK;
+
+	/* MT7530 Port6: Forced 1000M/FD, FC disabled */
+	priv->pmcr = val;
+
+	/* MT7530 Port5: Forced link down */
+	mt753x_reg_write(priv, PMCR_REG(5), FORCE_MODE);
+
+	/* Keep MAC link down before starting eth */
+	mt753x_reg_write(priv, PMCR_REG(6), FORCE_MODE);
+
+	/* MT7530 Port6: Set to RGMII */
+	mt753x_reg_rmw(priv, MT7530_P6ECR, P6_INTF_MODE_M, P6_INTF_MODE_RGMII);
+
+	/* Hardware Trap: Enable Port6, Disable Port5 */
+	mt753x_reg_read(priv, HWTRAP_REG, &val);
+	val |= CHG_TRAP | LOOPDET_DIS | P5_INTF_DIS |
+	       (P5_INTF_SEL_GMAC5 << P5_INTF_SEL_S) |
+	       (P5_INTF_MODE_RGMII << P5_INTF_MODE_S);
+	val &= ~(C_MDIO_BPS | P6_INTF_DIS);
+	mt753x_reg_write(priv, MHWTRAP_REG, val);
+
+	/* Setup switch core pll */
+	mt7530_pad_clk_setup(priv, priv->epriv.phy_interface);
+
+	/* Lower Tx Driving for TRGMII path */
+	for (i = 0 ; i < NUM_TRGMII_CTRL ; i++)
+		mt753x_reg_write(priv, MT7530_TRGMII_TD_ODT(i),
+				 (txdrv << TD_DM_DRVP_S) |
+				 (txdrv << TD_DM_DRVN_S));
+
+	for (i = 0 ; i < NUM_TRGMII_CTRL; i++)
+		mt753x_reg_rmw(priv, MT7530_TRGMII_RD(i), RD_TAP_M, 16);
+
+	/* Enable port isolation to block inter-port communication */
+	mt753x_port_isolation(priv);
+
+	/* Turn on PHYs */
+	for (i = 0; i < MT753X_NUM_PHYS; i++) {
+		phy_addr = MT753X_PHY_ADDR(priv->phy_base, i);
+		phy_val = mtk_mii_read(priv->epriv.eth, phy_addr, MII_BMCR);
+		phy_val &= ~BMCR_PDOWN;
+		mtk_mii_write(priv->epriv.eth, phy_addr, MII_BMCR, phy_val);
+	}
+
+	return mt7530_mdio_register(priv);
+}
+
+static int mt7530_cleanup(struct mtk_eth_switch_priv *swpriv)
+{
+	struct mt753x_switch_priv *priv = (struct mt753x_switch_priv *)swpriv;
+
+	mdio_unregister(priv->mdio_bus);
+
+	return 0;
+}
+
+static int mt7530_detect(struct mtk_eth_priv *priv)
+{
+	int ret;
+	u32 rev;
+
+	ret = __mt753x_mdio_reg_read(priv, MT753X_DFL_SMI_ADDR, CHIP_REV, &rev);
+	if (ret)
+		return ret;
+
+	if (((rev & CHIP_NAME_M) >> CHIP_NAME_S) == 0x7530)
+		return 0;
+
+	return -ENODEV;
+}
+
+MTK_ETH_SWITCH(mt7530) = {
+	.name = "mt7530",
+	.desc = "MediaTek MT7530",
+	.priv_size = sizeof(struct mt753x_switch_priv),
+	.reset_wait_time = 1000,
+
+	.detect = mt7530_detect,
+	.setup = mt7530_setup,
+	.cleanup = mt7530_cleanup,
+	.mac_control = mt7530_mac_control,
+};