1 files changed, 385 insertions, 0 deletions
diff --git a/drivers/net/mdio/mdio-mscc-miim.c b/drivers/net/mdio/mdio-mscc-miim.c
new file mode 100644
index 0000000000..1a1b95ae95
--- /dev/null
+++ b/drivers/net/mdio/mdio-mscc-miim.c
@@ -0,0 +1,385 @@
+// SPDX-License-Identifier: (GPL-2.0 OR MIT)
+/*
+ * Driver for the MDIO interface of Microsemi network switches.
+ *
+ * Author: Alexandre Belloni <alexandre.belloni@bootlin.com>
+ * Copyright (c) 2017 Microsemi Corporation
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/kernel.h>
+#include <linux/mdio/mdio-mscc-miim.h>
+#include <linux/mfd/ocelot.h>
+#include <linux/module.h>
+#include <linux/of_mdio.h>
+#include <linux/phy.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+
+#define MSCC_MIIM_REG_STATUS		0x0
+#define		MSCC_MIIM_STATUS_STAT_PENDING	BIT(2)
+#define		MSCC_MIIM_STATUS_STAT_BUSY	BIT(3)
+#define MSCC_MIIM_REG_CMD		0x8
+#define		MSCC_MIIM_CMD_OPR_WRITE		BIT(1)
+#define		MSCC_MIIM_CMD_OPR_READ		BIT(2)
+#define		MSCC_MIIM_CMD_WRDATA_SHIFT	4
+#define		MSCC_MIIM_CMD_REGAD_SHIFT	20
+#define		MSCC_MIIM_CMD_PHYAD_SHIFT	25
+#define		MSCC_MIIM_CMD_VLD		BIT(31)
+#define MSCC_MIIM_REG_DATA		0xC
+#define		MSCC_MIIM_DATA_ERROR		(BIT(16) | BIT(17))
+#define MSCC_MIIM_REG_CFG		0x10
+#define		MSCC_MIIM_CFG_PRESCALE_MASK	GENMASK(7, 0)
+
+#define MSCC_PHY_REG_PHY_CFG	0x0
+#define		PHY_CFG_PHY_ENA		(BIT(0) | BIT(1) | BIT(2) | BIT(3))
+#define		PHY_CFG_PHY_COMMON_RESET BIT(4)
+#define		PHY_CFG_PHY_RESET	(BIT(5) | BIT(6) | BIT(7) | BIT(8))
+#define MSCC_PHY_REG_PHY_STATUS	0x4
+
+#define LAN966X_CUPHY_COMMON_CFG	0x0
+#define		CUPHY_COMMON_CFG_RESET_N	BIT(0)
+
+struct mscc_miim_info {
+	unsigned int phy_reset_offset;
+	unsigned int phy_reset_bits;
+};
+
+struct mscc_miim_dev {
+	struct regmap *regs;
+	int mii_status_offset;
+	bool ignore_read_errors;
+	struct regmap *phy_regs;
+	const struct mscc_miim_info *info;
+	struct clk *clk;
+	u32 bus_freq;
+};
+
+/* When high resolution timers aren't built-in: we can't use usleep_range() as
+ * we would sleep way too long. Use udelay() instead.
+ */
+#define mscc_readx_poll_timeout(op, addr, val, cond, delay_us, timeout_us)\
+({									  \
+	if (!IS_ENABLED(CONFIG_HIGH_RES_TIMERS))			  \
+		readx_poll_timeout_atomic(op, addr, val, cond, delay_us,  \
+					  timeout_us);			  \
+	readx_poll_timeout(op, addr, val, cond, delay_us, timeout_us);	  \
+})
+
+static int mscc_miim_status(struct mii_bus *bus)
+{
+	struct mscc_miim_dev *miim = bus->priv;
+	int val, ret;
+
+	ret = regmap_read(miim->regs,
+			  MSCC_MIIM_REG_STATUS + miim->mii_status_offset, &val);
+	if (ret < 0) {
+		WARN_ONCE(1, "mscc miim status read error %d\n", ret);
+		return ret;
+	}
+
+	return val;
+}
+
+static int mscc_miim_wait_ready(struct mii_bus *bus)
+{
+	u32 val;
+
+	return mscc_readx_poll_timeout(mscc_miim_status, bus, val,
+				       !(val & MSCC_MIIM_STATUS_STAT_BUSY), 50,
+				       10000);
+}
+
+static int mscc_miim_wait_pending(struct mii_bus *bus)
+{
+	u32 val;
+
+	return mscc_readx_poll_timeout(mscc_miim_status, bus, val,
+				       !(val & MSCC_MIIM_STATUS_STAT_PENDING),
+				       50, 10000);
+}
+
+static int mscc_miim_read(struct mii_bus *bus, int mii_id, int regnum)
+{
+	struct mscc_miim_dev *miim = bus->priv;
+	u32 val;
+	int ret;
+
+	ret = mscc_miim_wait_pending(bus);
+	if (ret)
+		goto out;
+
+	ret = regmap_write(miim->regs,
+			   MSCC_MIIM_REG_CMD + miim->mii_status_offset,
+			   MSCC_MIIM_CMD_VLD |
+			   (mii_id << MSCC_MIIM_CMD_PHYAD_SHIFT) |
+			   (regnum << MSCC_MIIM_CMD_REGAD_SHIFT) |
+			   MSCC_MIIM_CMD_OPR_READ);
+
+	if (ret < 0) {
+		WARN_ONCE(1, "mscc miim write cmd reg error %d\n", ret);
+		goto out;
+	}
+
+	ret = mscc_miim_wait_ready(bus);
+	if (ret)
+		goto out;
+
+	ret = regmap_read(miim->regs,
+			  MSCC_MIIM_REG_DATA + miim->mii_status_offset, &val);
+	if (ret < 0) {
+		WARN_ONCE(1, "mscc miim read data reg error %d\n", ret);
+		goto out;
+	}
+
+	if (!miim->ignore_read_errors && !!(val & MSCC_MIIM_DATA_ERROR)) {
+		ret = -EIO;
+		goto out;
+	}
+
+	ret = val & 0xFFFF;
+out:
+	return ret;
+}
+
+static int mscc_miim_write(struct mii_bus *bus, int mii_id,
+			   int regnum, u16 value)
+{
+	struct mscc_miim_dev *miim = bus->priv;
+	int ret;
+
+	ret = mscc_miim_wait_pending(bus);
+	if (ret < 0)
+		goto out;
+
+	ret = regmap_write(miim->regs,
+			   MSCC_MIIM_REG_CMD + miim->mii_status_offset,
+			   MSCC_MIIM_CMD_VLD |
+			   (mii_id << MSCC_MIIM_CMD_PHYAD_SHIFT) |
+			   (regnum << MSCC_MIIM_CMD_REGAD_SHIFT) |
+			   (value << MSCC_MIIM_CMD_WRDATA_SHIFT) |
+			   MSCC_MIIM_CMD_OPR_WRITE);
+
+	if (ret < 0)
+		WARN_ONCE(1, "mscc miim write error %d\n", ret);
+out:
+	return ret;
+}
+
+static int mscc_miim_reset(struct mii_bus *bus)
+{
+	struct mscc_miim_dev *miim = bus->priv;
+	unsigned int offset, bits;
+	int ret;
+
+	if (!miim->phy_regs)
+		return 0;
+
+	offset = miim->info->phy_reset_offset;
+	bits = miim->info->phy_reset_bits;
+
+	ret = regmap_update_bits(miim->phy_regs, offset, bits, 0);
+	if (ret < 0) {
+		WARN_ONCE(1, "mscc reset set error %d\n", ret);
+		return ret;
+	}
+
+	ret = regmap_update_bits(miim->phy_regs, offset, bits, bits);
+	if (ret < 0) {
+		WARN_ONCE(1, "mscc reset clear error %d\n", ret);
+		return ret;
+	}
+
+	mdelay(500);
+
+	return 0;
+}
+
+static const struct regmap_config mscc_miim_regmap_config = {
+	.reg_bits	= 32,
+	.val_bits	= 32,
+	.reg_stride	= 4,
+};
+
+static const struct regmap_config mscc_miim_phy_regmap_config = {
+	.reg_bits	= 32,
+	.val_bits	= 32,
+	.reg_stride	= 4,
+	.name		= "phy",
+};
+
+int mscc_miim_setup(struct device *dev, struct mii_bus **pbus, const char *name,
+		    struct regmap *mii_regmap, int status_offset,
+		    bool ignore_read_errors)
+{
+	struct mscc_miim_dev *miim;
+	struct mii_bus *bus;
+
+	bus = devm_mdiobus_alloc_size(dev, sizeof(*miim));
+	if (!bus)
+		return -ENOMEM;
+
+	bus->name = name;
+	bus->read = mscc_miim_read;
+	bus->write = mscc_miim_write;
+	bus->reset = mscc_miim_reset;
+	snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii", dev_name(dev));
+	bus->parent = dev;
+
+	miim = bus->priv;
+
+	*pbus = bus;
+
+	miim->regs = mii_regmap;
+	miim->mii_status_offset = status_offset;
+	miim->ignore_read_errors = ignore_read_errors;
+
+	*pbus = bus;
+
+	return 0;
+}
+EXPORT_SYMBOL(mscc_miim_setup);
+
+static int mscc_miim_clk_set(struct mii_bus *bus)
+{
+	struct mscc_miim_dev *miim = bus->priv;
+	unsigned long rate;
+	u32 div;
+
+	/* Keep the current settings */
+	if (!miim->bus_freq)
+		return 0;
+
+	rate = clk_get_rate(miim->clk);
+
+	div = DIV_ROUND_UP(rate, 2 * miim->bus_freq) - 1;
+	if (div == 0 || div & ~MSCC_MIIM_CFG_PRESCALE_MASK) {
+		dev_err(&bus->dev, "Incorrect MDIO clock frequency\n");
+		return -EINVAL;
+	}
+
+	return regmap_update_bits(miim->regs, MSCC_MIIM_REG_CFG,
+				  MSCC_MIIM_CFG_PRESCALE_MASK, div);
+}
+
+static int mscc_miim_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct regmap *mii_regmap, *phy_regmap;
+	struct device *dev = &pdev->dev;
+	struct mscc_miim_dev *miim;
+	struct mii_bus *bus;
+	int ret;
+
+	mii_regmap = ocelot_regmap_from_resource(pdev, 0,
+						 &mscc_miim_regmap_config);
+	if (IS_ERR(mii_regmap))
+		return dev_err_probe(dev, PTR_ERR(mii_regmap),
+				     "Unable to create MIIM regmap\n");
+
+	/* This resource is optional */
+	phy_regmap = ocelot_regmap_from_resource_optional(pdev, 1,
+						 &mscc_miim_phy_regmap_config);
+	if (IS_ERR(phy_regmap))
+		return dev_err_probe(dev, PTR_ERR(phy_regmap),
+				     "Unable to create phy register regmap\n");
+
+	ret = mscc_miim_setup(dev, &bus, "mscc_miim", mii_regmap, 0, false);
+	if (ret < 0) {
+		dev_err(dev, "Unable to setup the MDIO bus\n");
+		return ret;
+	}
+
+	miim = bus->priv;
+	miim->phy_regs = phy_regmap;
+
+	miim->info = device_get_match_data(dev);
+	if (!miim->info)
+		return -EINVAL;
+
+	miim->clk = devm_clk_get_optional(dev, NULL);
+	if (IS_ERR(miim->clk))
+		return PTR_ERR(miim->clk);
+
+	of_property_read_u32(np, "clock-frequency", &miim->bus_freq);
+
+	if (miim->bus_freq && !miim->clk) {
+		dev_err(dev, "cannot use clock-frequency without a clock\n");
+		return -EINVAL;
+	}
+
+	ret = clk_prepare_enable(miim->clk);
+	if (ret)
+		return ret;
+
+	ret = mscc_miim_clk_set(bus);
+	if (ret)
+		goto out_disable_clk;
+
+	ret = of_mdiobus_register(bus, np);
+	if (ret < 0) {
+		dev_err(dev, "Cannot register MDIO bus (%d)\n", ret);
+		goto out_disable_clk;
+	}
+
+	platform_set_drvdata(pdev, bus);
+
+	return 0;
+
+out_disable_clk:
+	clk_disable_unprepare(miim->clk);
+	return ret;
+}
+
+static int mscc_miim_remove(struct platform_device *pdev)
+{
+	struct mii_bus *bus = platform_get_drvdata(pdev);
+	struct mscc_miim_dev *miim = bus->priv;
+
+	clk_disable_unprepare(miim->clk);
+	mdiobus_unregister(bus);
+
+	return 0;
+}
+
+static const struct mscc_miim_info mscc_ocelot_miim_info = {
+	.phy_reset_offset = MSCC_PHY_REG_PHY_CFG,
+	.phy_reset_bits = PHY_CFG_PHY_ENA | PHY_CFG_PHY_COMMON_RESET |
+			  PHY_CFG_PHY_RESET,
+};
+
+static const struct mscc_miim_info microchip_lan966x_miim_info = {
+	.phy_reset_offset = LAN966X_CUPHY_COMMON_CFG,
+	.phy_reset_bits = CUPHY_COMMON_CFG_RESET_N,
+};
+
+static const struct of_device_id mscc_miim_match[] = {
+	{
+		.compatible = "mscc,ocelot-miim",
+		.data = &mscc_ocelot_miim_info
+	}, {
+		.compatible = "microchip,lan966x-miim",
+		.data = &microchip_lan966x_miim_info
+	},
+	{ }
+};
+MODULE_DEVICE_TABLE(of, mscc_miim_match);
+
+static struct platform_driver mscc_miim_driver = {
+	.probe = mscc_miim_probe,
+	.remove = mscc_miim_remove,
+	.driver = {
+		.name = "mscc-miim",
+		.of_match_table = mscc_miim_match,
+	},
+};
+
+module_platform_driver(mscc_miim_driver);
+
+MODULE_DESCRIPTION("Microsemi MIIM driver");
+MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@bootlin.com>");
+MODULE_LICENSE("Dual MIT/GPL");