net: dsa: ocelot: felix: utilize shared mscc-miim driver for indirect MDIO access

Switch to a shared MDIO access implementation by way of the mdio-mscc-miim
driver.
Signed-off-by: Colin Foster <colin.foster@in-advantage.com>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/ocelot/Kconfig

@@ -21,6 +21,7 @@ config NET_DSA_MSCC_SEVILLE
 	depends on NET_VENDOR_MICROSEMI
 	depends on HAS_IOMEM
 	depends on PTP_1588_CLOCK_OPTIONAL
+	select MDIO_MSCC_MIIM
 	select MSCC_OCELOT_SWITCH_LIB
 	select NET_DSA_TAG_OCELOT_8021Q
 	select NET_DSA_TAG_OCELOT

drivers/net/dsa/ocelot/seville_vsc9953.c

@@ -6,19 +6,14 @@
 #include <soc/mscc/ocelot_vcap.h>
 #include <soc/mscc/ocelot_sys.h>
 #include <soc/mscc/ocelot.h>
+#include <linux/mdio/mdio-mscc-miim.h>
+#include <linux/of_mdio.h>
 #include <linux/of_platform.h>
 #include <linux/pcs-lynx.h>
 #include <linux/dsa/ocelot.h>
 #include <linux/iopoll.h>
-#include <linux/of_mdio.h>
 #include "felix.h"
 
-#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 VSC9953_VCAP_POLICER_BASE		11
 #define VSC9953_VCAP_POLICER_MAX		31
 #define VSC9953_VCAP_POLICER_BASE2		120
@@ -862,7 +857,6 @@ static struct vcap_props vsc9953_vcap_props[] = {
 #define VSC9953_INIT_TIMEOUT			50000
 #define VSC9953_GCB_RST_SLEEP			100
 #define VSC9953_SYS_RAMINIT_SLEEP		80
-#define VCS9953_MII_TIMEOUT			10000
 
 static int vsc9953_gcb_soft_rst_status(struct ocelot *ocelot)
 {
@@ -882,82 +876,6 @@ static int vsc9953_sys_ram_init_status(struct ocelot *ocelot)
 	return val;
 }
 
-static int vsc9953_gcb_miim_pending_status(struct ocelot *ocelot)
-{
-	int val;
-
-	ocelot_field_read(ocelot, GCB_MIIM_MII_STATUS_PENDING, &val);
-
-	return val;
-}
-
-static int vsc9953_gcb_miim_busy_status(struct ocelot *ocelot)
-{
-	int val;
-
-	ocelot_field_read(ocelot, GCB_MIIM_MII_STATUS_BUSY, &val);
-
-	return val;
-}
-
-static int vsc9953_mdio_write(struct mii_bus *bus, int phy_id, int regnum,
-			      u16 value)
-{
-	struct ocelot *ocelot = bus->priv;
-	int err, cmd, val;
-
-	/* Wait while MIIM controller becomes idle */
-	err = readx_poll_timeout(vsc9953_gcb_miim_pending_status, ocelot,
-				 val, !val, 10, VCS9953_MII_TIMEOUT);
-	if (err) {
-		dev_err(ocelot->dev, "MDIO write: pending timeout\n");
-		goto out;
-	}
-
-	cmd = MSCC_MIIM_CMD_VLD | (phy_id << MSCC_MIIM_CMD_PHYAD_SHIFT) |
-	      (regnum << MSCC_MIIM_CMD_REGAD_SHIFT) |
-	      (value << MSCC_MIIM_CMD_WRDATA_SHIFT) |
-	      MSCC_MIIM_CMD_OPR_WRITE;
-
-	ocelot_write(ocelot, cmd, GCB_MIIM_MII_CMD);
-
-out:
-	return err;
-}
-
-static int vsc9953_mdio_read(struct mii_bus *bus, int phy_id, int regnum)
-{
-	struct ocelot *ocelot = bus->priv;
-	int err, cmd, val;
-
-	/* Wait until MIIM controller becomes idle */
-	err = readx_poll_timeout(vsc9953_gcb_miim_pending_status, ocelot,
-				 val, !val, 10, VCS9953_MII_TIMEOUT);
-	if (err) {
-		dev_err(ocelot->dev, "MDIO read: pending timeout\n");
-		goto out;
-	}
-
-	/* Write the MIIM COMMAND register */
-	cmd = MSCC_MIIM_CMD_VLD | (phy_id << MSCC_MIIM_CMD_PHYAD_SHIFT) |
-	      (regnum << MSCC_MIIM_CMD_REGAD_SHIFT) | MSCC_MIIM_CMD_OPR_READ;
-
-	ocelot_write(ocelot, cmd, GCB_MIIM_MII_CMD);
-
-	/* Wait while read operation via the MIIM controller is in progress */
-	err = readx_poll_timeout(vsc9953_gcb_miim_busy_status, ocelot,
-				 val, !val, 10, VCS9953_MII_TIMEOUT);
-	if (err) {
-		dev_err(ocelot->dev, "MDIO read: busy timeout\n");
-		goto out;
-	}
-
-	val = ocelot_read(ocelot, GCB_MIIM_MII_DATA);
-
-	err = val & 0xFFFF;
-out:
-	return err;
-}
 
 /* CORE_ENA is in SYS:SYSTEM:RESET_CFG
  * MEM_INIT is in SYS:SYSTEM:RESET_CFG
@@ -1101,16 +1019,14 @@ static int vsc9953_mdio_bus_alloc(struct ocelot *ocelot)
 		return -ENOMEM;
 	}
 
-	bus = devm_mdiobus_alloc(dev);
-	if (!bus)
-		return -ENOMEM;
+	rc = mscc_miim_setup(dev, &bus, "VSC9953 internal MDIO bus",
+			     ocelot->targets[GCB],
+			     ocelot->map[GCB][GCB_MIIM_MII_STATUS & REG_MASK]);
 
-	bus->name = "VSC9953 internal MDIO bus";
-	bus->read = vsc9953_mdio_read;
-	bus->write = vsc9953_mdio_write;
-	bus->parent = dev;
-	bus->priv = ocelot;
-	snprintf(bus->id, MII_BUS_ID_SIZE, "%s-imdio", dev_name(dev));
+	if (rc) {
+		dev_err(dev, "failed to setup MDIO bus\n");
+		return rc;
+	}
 
 	/* Needed in order to initialize the bus mutex lock */
 	rc = of_mdiobus_register(bus, NULL);

drivers/net/mdio/mdio-mscc-miim.c

@@ -10,6 +10,7 @@
 #include <linux/io.h>
 #include <linux/iopoll.h>
 #include <linux/kernel.h>
+#include <linux/mdio/mdio-mscc-miim.h>
 #include <linux/module.h>
 #include <linux/of_mdio.h>
 #include <linux/phy.h>
@@ -37,7 +38,9 @@
 
 struct mscc_miim_dev {
 	struct regmap *regs;
+	int mii_status_offset;
 	struct regmap *phy_regs;
+	int phy_reset_offset;
 };
 
 /* When high resolution timers aren't built-in: we can't use usleep_range() as
@@ -56,7 +59,8 @@ 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, &val);
+	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;
@@ -93,7 +97,9 @@ static int mscc_miim_read(struct mii_bus *bus, int mii_id, int regnum)
 	if (ret)
 		goto out;
 
-	ret = regmap_write(miim->regs, MSCC_MIIM_REG_CMD, MSCC_MIIM_CMD_VLD |
+	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);
@@ -107,8 +113,8 @@ static int mscc_miim_read(struct mii_bus *bus, int mii_id, int regnum)
 	if (ret)
 		goto out;
 
-	ret = regmap_read(miim->regs, MSCC_MIIM_REG_DATA, &val);
-
+	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;
@@ -134,7 +140,9 @@ static int mscc_miim_write(struct mii_bus *bus, int mii_id,
 	if (ret < 0)
 		goto out;
 
-	ret = regmap_write(miim->regs, MSCC_MIIM_REG_CMD, MSCC_MIIM_CMD_VLD |
+	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) |
@@ -149,16 +157,19 @@ static int mscc_miim_write(struct mii_bus *bus, int mii_id,
 static int mscc_miim_reset(struct mii_bus *bus)
 {
 	struct mscc_miim_dev *miim = bus->priv;
+	int offset = miim->phy_reset_offset;
 	int ret;
 
 	if (miim->phy_regs) {
-		ret = regmap_write(miim->phy_regs, MSCC_PHY_REG_PHY_CFG, 0);
+		ret = regmap_write(miim->phy_regs,
+				   MSCC_PHY_REG_PHY_CFG + offset, 0);
 		if (ret < 0) {
 			WARN_ONCE(1, "mscc reset set error %d\n", ret);
 			return ret;
 		}
 
-		ret = regmap_write(miim->phy_regs, MSCC_PHY_REG_PHY_CFG, 0x1ff);
+		ret = regmap_write(miim->phy_regs,
+				   MSCC_PHY_REG_PHY_CFG + offset, 0x1ff);
 		if (ret < 0) {
 			WARN_ONCE(1, "mscc reset clear error %d\n", ret);
 			return ret;
@@ -176,8 +187,8 @@ static const struct regmap_config mscc_miim_regmap_config = {
 	.reg_stride	= 4,
 };
 
-static int mscc_miim_setup(struct device *dev, struct mii_bus **pbus,
-			   struct regmap *mii_regmap)
+int mscc_miim_setup(struct device *dev, struct mii_bus **pbus, const char *name,
+		    struct regmap *mii_regmap, int status_offset)
 {
 	struct mscc_miim_dev *miim;
 	struct mii_bus *bus;
@@ -186,7 +197,7 @@ static int mscc_miim_setup(struct device *dev, struct mii_bus **pbus,
 	if (!bus)
 		return -ENOMEM;
 
-	bus->name = "mscc_miim";
+	bus->name = name;
 	bus->read = mscc_miim_read;
 	bus->write = mscc_miim_write;
 	bus->reset = mscc_miim_reset;
@@ -198,9 +209,13 @@ static int mscc_miim_setup(struct device *dev, struct mii_bus **pbus,
 	*pbus = bus;
 
 	miim->regs = mii_regmap;
+	miim->mii_status_offset = status_offset;
+
+	*pbus = bus;
 
 	return 0;
 }
+EXPORT_SYMBOL(mscc_miim_setup);
 
 static int mscc_miim_probe(struct platform_device *pdev)
 {
@@ -237,7 +252,7 @@ static int mscc_miim_probe(struct platform_device *pdev)
 		return PTR_ERR(phy_regmap);
 	}
 
-	ret = mscc_miim_setup(&pdev->dev, &bus, mii_regmap);
+	ret = mscc_miim_setup(&pdev->dev, &bus, "mscc_miim", mii_regmap, 0);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "Unable to setup the MDIO bus\n");
 		return ret;
@@ -245,6 +260,7 @@ static int mscc_miim_probe(struct platform_device *pdev)
 
 	miim = bus->priv;
 	miim->phy_regs = phy_regmap;
+	miim->phy_reset_offset = 0;
 
 	ret = of_mdiobus_register(bus, pdev->dev.of_node);
 	if (ret < 0) {

include/linux/mdio/mdio-mscc-miim.h

+/* SPDX-License-Identifier: (GPL-2.0 OR MIT) */
+/*
+ * Driver for the MDIO interface of Microsemi network switches.
+ *
+ * Author: Colin Foster <colin.foster@in-advantage.com>
+ * Copyright (C) 2021 Innovative Advantage
+ */
+#ifndef MDIO_MSCC_MIIM_H
+#define MDIO_MSCC_MIIM_H
+
+#include <linux/device.h>
+#include <linux/phy.h>
+#include <linux/regmap.h>
+
+int mscc_miim_setup(struct device *device, struct mii_bus **bus,
+		    const char *name, struct regmap *mii_regmap,
+		    int status_offset);
+
+#endif