[RFC PATCH v4 net-next 04/23] net: dsa: ocelot: felix: switch to mdio-mscc-miim driver for indirect mdio access

[Colin Foster <colin.foster@xxxxxxxxxxxxxxxx>]

Switch to a shared MDIO access implementation now provided by
drivers/net/mdio/mdio-mscc-miim.c

Signed-off-by: Colin Foster <colin.foster@xxxxxxxxxxxxxxxx>
---
 drivers/net/dsa/ocelot/Kconfig           |   1 +
 drivers/net/dsa/ocelot/Makefile          |   1 +
 drivers/net/dsa/ocelot/felix_mdio.c      |  54 ++++++++++++
 drivers/net/dsa/ocelot/felix_mdio.h      |  13 +++
 drivers/net/dsa/ocelot/seville_vsc9953.c | 108 ++---------------------
 drivers/net/mdio/mdio-mscc-miim.c        |  37 +++++---
 include/linux/mdio/mdio-mscc-miim.h      |  19 ++++
 7 files changed, 123 insertions(+), 110 deletions(-)
 create mode 100644 drivers/net/dsa/ocelot/felix_mdio.c
 create mode 100644 drivers/net/dsa/ocelot/felix_mdio.h
 create mode 100644 include/linux/mdio/mdio-mscc-miim.h

diff --git a/drivers/net/dsa/ocelot/Kconfig b/drivers/net/dsa/ocelot/Kconfig
index 9948544ba1c4..220b0b027b55 100644
--- a/drivers/net/dsa/ocelot/Kconfig
+++ b/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
diff --git a/drivers/net/dsa/ocelot/Makefile b/drivers/net/dsa/ocelot/Makefile
index f6dd131e7491..34b9b128efb8 100644
--- a/drivers/net/dsa/ocelot/Makefile
+++ b/drivers/net/dsa/ocelot/Makefile
@@ -8,4 +8,5 @@ mscc_felix-objs := \
 
 mscc_seville-objs := \
 	felix.o \
+	felix_mdio.o \
 	seville_vsc9953.o
diff --git a/drivers/net/dsa/ocelot/felix_mdio.c b/drivers/net/dsa/ocelot/felix_mdio.c
new file mode 100644
index 000000000000..34375285756b
--- /dev/null
+++ b/drivers/net/dsa/ocelot/felix_mdio.c
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: (GPL-2.0 OR MIT)
+/* Distributed Switch Architecture VSC9953 driver
+ * Copyright (C) 2020, Maxim Kochetkov <fido_max@xxxxxxxx>
+ * Copyright (C) 2021 Innovative Advantage
+ */
+#include <linux/of_mdio.h>
+#include <linux/types.h>
+#include <soc/mscc/ocelot.h>
+#include <linux/dsa/ocelot.h>
+#include <linux/mdio/mdio-mscc-miim.h>
+#include "felix.h"
+#include "felix_mdio.h"
+
+int felix_of_mdio_register(struct ocelot *ocelot, struct device_node *np)
+{
+	struct felix *felix = ocelot_to_felix(ocelot);
+	struct device *dev = ocelot->dev;
+	int rc;
+
+	/* Needed in order to initialize the bus mutex lock */
+	rc = of_mdiobus_register(felix->imdio, np);
+	if (rc < 0) {
+		dev_err(dev, "failed to register MDIO bus\n");
+		felix->imdio = NULL;
+	}
+
+	return rc;
+}
+
+int felix_mdio_bus_alloc(struct ocelot *ocelot)
+{
+	struct felix *felix = ocelot_to_felix(ocelot);
+	struct device *dev = ocelot->dev;
+	struct mii_bus *bus;
+	int err;
+
+	err = mscc_miim_setup(dev, &bus, ocelot->targets[GCB],
+			      ocelot->map[GCB][GCB_MIIM_MII_STATUS & REG_MASK],
+			      ocelot->targets[GCB],
+			      ocelot->map[GCB][GCB_PHY_PHY_CFG & REG_MASK]);
+
+	if (!err)
+		felix->imdio = bus;
+
+	return err;
+}
+
+void felix_mdio_bus_free(struct ocelot *ocelot)
+{
+	struct felix *felix = ocelot_to_felix(ocelot);
+
+	if (felix->imdio)
+		mdiobus_unregister(felix->imdio);
+}
diff --git a/drivers/net/dsa/ocelot/felix_mdio.h b/drivers/net/dsa/ocelot/felix_mdio.h
new file mode 100644
index 000000000000..93286f598c3b
--- /dev/null
+++ b/drivers/net/dsa/ocelot/felix_mdio.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0 OR MIT */
+/* Shared code for indirect MDIO access for Felix drivers
+ *
+ * Author: Colin Foster <colin.foster@xxxxxxxxxxxxxxxx>
+ * Copyright (C) 2021 Innovative Advantage
+ */
+#include <linux/of.h>
+#include <linux/types.h>
+#include <soc/mscc/ocelot.h>
+
+int felix_mdio_bus_alloc(struct ocelot *ocelot);
+int felix_of_mdio_register(struct ocelot *ocelot, struct device_node *np);
+void felix_mdio_bus_free(struct ocelot *ocelot);
diff --git a/drivers/net/dsa/ocelot/seville_vsc9953.c b/drivers/net/dsa/ocelot/seville_vsc9953.c
index 84681642d237..610bdfd31903 100644
--- a/drivers/net/dsa/ocelot/seville_vsc9953.c
+++ b/drivers/net/dsa/ocelot/seville_vsc9953.c
@@ -11,13 +11,7 @@
 #include <linux/dsa/ocelot.h>
 #include <linux/iopoll.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)
+#include "felix_mdio.h"
 
 static const u32 vsc9953_ana_regmap[] = {
 	REG(ANA_ADVLEARN,			0x00b500),
@@ -857,7 +851,6 @@ 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)
 {
@@ -877,82 +870,6 @@ 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
@@ -1084,7 +1001,6 @@ static int vsc9953_mdio_bus_alloc(struct ocelot *ocelot)
 {
 	struct felix *felix = ocelot_to_felix(ocelot);
 	struct device *dev = ocelot->dev;
-	struct mii_bus *bus;
 	int port;
 	int rc;
 
@@ -1096,26 +1012,18 @@ static int vsc9953_mdio_bus_alloc(struct ocelot *ocelot)
 		return -ENOMEM;
 	}
 
-	bus = devm_mdiobus_alloc(dev);
-	if (!bus)
-		return -ENOMEM;
-
-	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));
+	rc = felix_mdio_bus_alloc(ocelot);
+	if (rc < 0) {
+		dev_err(dev, "failed to allocate MDIO bus\n");
+		return rc;
+	}
 
-	/* Needed in order to initialize the bus mutex lock */
-	rc = of_mdiobus_register(bus, NULL);
+	rc = felix_of_mdio_register(ocelot, NULL);
 	if (rc < 0) {
 		dev_err(dev, "failed to register MDIO bus\n");
 		return rc;
 	}
 
-	felix->imdio = bus;
-
 	for (port = 0; port < felix->info->num_ports; port++) {
 		struct ocelot_port *ocelot_port = ocelot->ports[port];
 		int addr = port + 4;
@@ -1160,7 +1068,7 @@ static void vsc9953_mdio_bus_free(struct ocelot *ocelot)
 		mdio_device_free(pcs->mdio);
 		lynx_pcs_destroy(pcs);
 	}
-	mdiobus_unregister(felix->imdio);
+	felix_mdio_bus_free(ocelot);
 }
 
 static const struct felix_info seville_info_vsc9953 = {
diff --git a/drivers/net/mdio/mdio-mscc-miim.c b/drivers/net/mdio/mdio-mscc-miim.c
index ea599b980bbf..cf3fa7a4459c 100644
--- a/drivers/net/mdio/mdio-mscc-miim.c
+++ b/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, err;
 
-	err = regmap_read(miim->regs, MSCC_MIIM_REG_STATUS, &val);
+	err = regmap_read(miim->regs,
+			  MSCC_MIIM_REG_STATUS + miim->mii_status_offset, &val);
 	if (err < 0)
 		WARN_ONCE(1, "mscc miim status read error %d\n", err);
 
@@ -91,7 +95,9 @@ static int mscc_miim_read(struct mii_bus *bus, int mii_id, int regnum)
 	if (ret)
 		goto out;
 
-	err = regmap_write(miim->regs, MSCC_MIIM_REG_CMD, MSCC_MIIM_CMD_VLD |
+	err = 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);
@@ -103,7 +109,8 @@ static int mscc_miim_read(struct mii_bus *bus, int mii_id, int regnum)
 	if (ret)
 		goto out;
 
-	err = regmap_read(miim->regs, MSCC_MIIM_REG_DATA, &val);
+	err = regmap_read(miim->regs,
+			  MSCC_MIIM_REG_DATA + miim->mii_status_offset, &val);
 
 	if (err < 0)
 		WARN_ONCE(1, "mscc miim read data reg error %d\n", err);
@@ -128,7 +135,9 @@ static int mscc_miim_write(struct mii_bus *bus, int mii_id,
 	if (ret < 0)
 		goto out;
 
-	err = regmap_write(miim->regs, MSCC_MIIM_REG_CMD, MSCC_MIIM_CMD_VLD |
+	err = 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) |
@@ -143,14 +152,17 @@ 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 err;
 
 	if (miim->phy_regs) {
-		err = regmap_write(miim->phy_regs, MSCC_PHY_REG_PHY_CFG, 0);
+		err = regmap_write(miim->phy_regs,
+				   MSCC_PHY_REG_PHY_CFG + offset, 0);
 		if (err < 0)
 			WARN_ONCE(1, "mscc reset set error %d\n", err);
 
-		err = regmap_write(miim->phy_regs, MSCC_PHY_REG_PHY_CFG, 0x1ff);
+		err = regmap_write(miim->phy_regs,
+				   MSCC_PHY_REG_PHY_CFG + offset, 0x1ff);
 		if (err < 0)
 			WARN_ONCE(1, "mscc reset clear error %d\n", err);
 
@@ -166,12 +178,12 @@ static const struct regmap_config mscc_miim_regmap_config = {
 	.reg_stride	= 4,
 };
 
-static int mscc_miim_setup(struct device *dev, struct mii_bus *bus,
-			   struct regmap *mii_regmap, struct regmap *phy_regmap)
+int mscc_miim_setup(struct device *dev, struct mii_bus **pbus,
+		    struct regmap *mii_regmap, int status_offset,
+		    struct regmap *phy_regmap, int reset_offset)
 {
 	struct mscc_miim_dev *miim;
 	struct mii_bus *bus;
-	int ret;
 
 	bus = devm_mdiobus_alloc_size(dev, sizeof(*miim));
 	if (!bus)
@@ -187,10 +199,15 @@ static int mscc_miim_setup(struct device *dev, struct mii_bus *bus,
 	miim = bus->priv;
 
 	miim->regs = mii_regmap;
+	miim->mii_status_offset = status_offset;
 	miim->phy_regs = phy_regmap;
+	miim->phy_reset_offset = reset_offset;
+
+	*pbus = bus;
 
 	return 0;
 }
+EXPORT_SYMBOL(mscc_miim_setup);
 
 static int mscc_miim_probe(struct platform_device *pdev)
 {
@@ -227,7 +244,7 @@ static int mscc_miim_probe(struct platform_device *pdev)
 		return PTR_ERR(dev->phy_regs);
 	}
 
-	mscc_miim_setup(&pdev->dev, bus, mii_regmap, phy_regmap);
+	mscc_miim_setup(&pdev->dev, &bus, mii_regmap, 0, phy_regmap, 0);
 
 	ret = of_mdiobus_register(bus, pdev->dev.of_node);
 	if (ret < 0) {
diff --git a/include/linux/mdio/mdio-mscc-miim.h b/include/linux/mdio/mdio-mscc-miim.h
new file mode 100644
index 000000000000..3ceab7b6ffc1
--- /dev/null
+++ b/include/linux/mdio/mdio-mscc-miim.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: (GPL-2.0 OR MIT) */
+/*
+ * Driver for the MDIO interface of Microsemi network switches.
+ *
+ * Author: Colin Foster <colin.foster@xxxxxxxxxxxxxxxx>
+ * 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,
+		    struct regmap *mii_regmap, int status_offset,
+		    struct regmap *phy_regmap, int reset_offset);
+
+#endif
-- 
2.25.1