[PATCH v1 2/5] net: hpe: Add GXP UMAC MDIO

[nick.hawkins@hpe.com]

From: Nick Hawkins <nick.hawkins@hpe.com>

The GXP contains two Universal Ethernet MACs that can be
connected externally to several physical devices. From an external
interface perspective the BMC provides two SERDES interface connections
capable of either SGMII or 1000Base-X operation. The BMC also provides
a RMII interface for sideband connections to external Ethernet controllers.

The primary MAC (umac0) can be mapped to either SGMII/1000-BaseX
SERDES interface.  The secondary MAC (umac1) can be mapped to only
the second SGMII/1000-Base X Serdes interface or it can be mapped for
RMII sideband.

The MDIO(mdio0) interface from the primary MAC (umac0) is used for
external PHY status and configuration. The MDIO(mdio1) interface from
the secondary MAC (umac1) is routed to the SGMII/100Base-X IP blocks
on the two SERDES interface connections.

Signed-off-by: Nick Hawkins <nick.hawkins@hpe.com>
---
 drivers/net/ethernet/Kconfig             |   1 +
 drivers/net/ethernet/Makefile            |   1 +
 drivers/net/ethernet/hpe/Kconfig         |  28 ++++
 drivers/net/ethernet/hpe/Makefile        |   1 +
 drivers/net/ethernet/hpe/gxp-umac-mdio.c | 158 +++++++++++++++++++++++
 5 files changed, 189 insertions(+)
 create mode 100644 drivers/net/ethernet/hpe/Kconfig
 create mode 100644 drivers/net/ethernet/hpe/Makefile
 create mode 100644 drivers/net/ethernet/hpe/gxp-umac-mdio.c

diff --git a/drivers/net/ethernet/Kconfig b/drivers/net/ethernet/Kconfig
index 5a274b99f299..b4921b84be51 100644
--- a/drivers/net/ethernet/Kconfig
+++ b/drivers/net/ethernet/Kconfig
@@ -80,6 +80,7 @@ source "drivers/net/ethernet/fujitsu/Kconfig"
 source "drivers/net/ethernet/fungible/Kconfig"
 source "drivers/net/ethernet/google/Kconfig"
 source "drivers/net/ethernet/hisilicon/Kconfig"
+source "drivers/net/ethernet/hpe/Kconfig"
 source "drivers/net/ethernet/huawei/Kconfig"
 source "drivers/net/ethernet/i825xx/Kconfig"
 source "drivers/net/ethernet/ibm/Kconfig"
diff --git a/drivers/net/ethernet/Makefile b/drivers/net/ethernet/Makefile
index 0d872d4efcd1..2e3cae9dbe97 100644
--- a/drivers/net/ethernet/Makefile
+++ b/drivers/net/ethernet/Makefile
@@ -44,6 +44,7 @@ obj-$(CONFIG_NET_VENDOR_FREESCALE) += freescale/
 obj-$(CONFIG_NET_VENDOR_FUJITSU) += fujitsu/
 obj-$(CONFIG_NET_VENDOR_FUNGIBLE) += fungible/
 obj-$(CONFIG_NET_VENDOR_GOOGLE) += google/
+obj-$(CONFIG_NET_VENDOR_HPE) += hpe/
 obj-$(CONFIG_NET_VENDOR_HISILICON) += hisilicon/
 obj-$(CONFIG_NET_VENDOR_HUAWEI) += huawei/
 obj-$(CONFIG_NET_VENDOR_IBM) += ibm/
diff --git a/drivers/net/ethernet/hpe/Kconfig b/drivers/net/ethernet/hpe/Kconfig
new file mode 100644
index 000000000000..461aa15ace34
--- /dev/null
+++ b/drivers/net/ethernet/hpe/Kconfig
@@ -0,0 +1,28 @@
+config NET_VENDOR_HPE
+	bool "HPE device"
+	default y
+	depends on ARCH_HPE
+	help
+	  Say y here to support the HPE network devices.
+	  The GXP contains two Ethernet MACs that can be
+	  connected externally to several physical devices.
+	  From an external interface perspective the BMC
+	  provides two SERDES interface connections capable
+	  of either SGMII or 1000Base-X operation. The BMC
+	  also provides a RMII interface for sideband
+	  connections to external Ethernet controllers.
+
+if NET_VENDOR_HPE
+
+config GXP_UMAC_MDIO
+	tristate "GXP UMAC mdio support"
+	depends on ARCH_HPE
+	help
+	  Say y here to support the GXP UMAC MDIO bus. The
+	  MDIO(mdio0) interface from the primary MAC (umac0)
+	  is used for external PHY status and configuration.
+	  The MDIO(mdio1) interface from the secondary MAC
+	  (umac1) is routed to the SGMII/100Base-X IP blocks
+	  on the two SERDES interface connections.
+
+endif
diff --git a/drivers/net/ethernet/hpe/Makefile b/drivers/net/ethernet/hpe/Makefile
new file mode 100644
index 000000000000..e84c8786ba04
--- /dev/null
+++ b/drivers/net/ethernet/hpe/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_GXP_UMAC_MDIO) += gxp-umac-mdio.o
diff --git a/drivers/net/ethernet/hpe/gxp-umac-mdio.c b/drivers/net/ethernet/hpe/gxp-umac-mdio.c
new file mode 100644
index 000000000000..763e59185409
--- /dev/null
+++ b/drivers/net/ethernet/hpe/gxp-umac-mdio.c
@@ -0,0 +1,158 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (C) 2023 Hewlett-Packard Development Company, L.P. */
+
+#include <linux/err.h>
+#include <linux/iopoll.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_mdio.h>
+#include <linux/platform_device.h>
+
+#define UMAC_MII                0x00  /* R/W MII Register */
+#define UMAC_MII_PHY_ADDR_MASK  0x001F0000
+#define UMAC_MII_PHY_ADDR_SHIFT 16
+#define UMAC_MII_MOWNER         0x00000200
+#define UMAC_MII_MRNW           0x00000100
+#define UMAC_MII_REG_ADDR_MASK  0x0000001F
+#define UMAC_MII_DATA           0x04  /* R/W MII Data Register */
+
+struct umac_mdio_priv {
+	void __iomem *base;
+};
+
+static int umac_mdio_read(struct mii_bus *bus, int phy_id, int reg)
+{
+	struct umac_mdio_priv *umac_mdio = bus->priv;
+	unsigned int value;
+	unsigned int status;
+	int ret;
+
+	status = __raw_readl(umac_mdio->base + UMAC_MII);
+
+	status &= ~(UMAC_MII_PHY_ADDR_MASK | UMAC_MII_REG_ADDR_MASK);
+	status |= ((phy_id << UMAC_MII_PHY_ADDR_SHIFT) &
+			UMAC_MII_PHY_ADDR_MASK);
+	status |= (reg & UMAC_MII_REG_ADDR_MASK);
+	status |= UMAC_MII_MRNW; /* set bit for read mode */
+	__raw_writel(status, umac_mdio->base + UMAC_MII);
+
+	status |= UMAC_MII_MOWNER; /* set bit to activate mii transfer */
+	__raw_writel(status, umac_mdio->base + UMAC_MII);
+
+	ret = readl_poll_timeout(umac_mdio->base + UMAC_MII, status,
+				 !(status & UMAC_MII_MOWNER), 1000, 100000);
+	if (ret) {
+		dev_err(bus->parent, "mdio read time out\n");
+		return -ETIMEDOUT;
+	}
+
+	value = __raw_readl(umac_mdio->base + UMAC_MII_DATA);
+	return value;
+}
+
+static int umac_mdio_write(struct mii_bus *bus, int phy_id, int reg, u16 value)
+{
+	struct umac_mdio_priv *umac_mdio = bus->priv;
+	unsigned int status;
+	int ret;
+
+	__raw_writel(value, umac_mdio->base + UMAC_MII_DATA);
+
+	status = __raw_readl(umac_mdio->base + UMAC_MII);
+
+	status &= ~(UMAC_MII_PHY_ADDR_MASK | UMAC_MII_REG_ADDR_MASK);
+	status |= ((phy_id << UMAC_MII_PHY_ADDR_SHIFT) &
+			UMAC_MII_PHY_ADDR_MASK);
+	status |= (reg & UMAC_MII_REG_ADDR_MASK);
+	status &= ~UMAC_MII_MRNW; /* clear bit for write mode */
+	__raw_writel(status, umac_mdio->base + UMAC_MII);
+
+	status |= UMAC_MII_MOWNER; /* set bit to activate mii transfer */
+	__raw_writel(status, umac_mdio->base + UMAC_MII);
+
+	ret = readl_poll_timeout(umac_mdio->base + UMAC_MII, status,
+				 !(status & UMAC_MII_MOWNER), 1000, 100000);
+	if (ret) {
+		dev_err(bus->parent, "mdio read time out\n");
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+
+static int umac_mdio_probe(struct platform_device *pdev)
+{
+	struct resource *res;
+	struct mii_bus *bus;
+	struct umac_mdio_priv *umac_mdio;
+
+	int ret;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(&pdev->dev, "fail to get resource\n");
+		return -ENODEV;
+	}
+
+	bus = devm_mdiobus_alloc_size(&pdev->dev,
+				      sizeof(struct umac_mdio_priv));
+	if (!bus) {
+		dev_err(&pdev->dev, "failed to alloc mii bus\n");
+		return -ENOMEM;
+	}
+
+	snprintf(bus->id, MII_BUS_ID_SIZE, "%s", dev_name(&pdev->dev));
+
+	bus->name	= dev_name(&pdev->dev);
+	bus->read	= umac_mdio_read,
+	bus->write	= umac_mdio_write,
+	bus->parent	= &pdev->dev;
+	umac_mdio = bus->priv;
+	umac_mdio->base = devm_ioremap_resource(&pdev->dev, res);
+	if (!umac_mdio->base) {
+		dev_err(&pdev->dev, "failed to do ioremap\n");
+		return -ENODEV;
+	}
+
+	platform_set_drvdata(pdev, umac_mdio);
+
+	ret = of_mdiobus_register(bus, pdev->dev.of_node);
+
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Cannot register MDIO bus (%d)\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int umac_mdio_remove(struct platform_device *pdev)
+{
+	struct mii_bus *bus = platform_get_drvdata(pdev);
+
+	if (bus)
+		mdiobus_unregister(bus);
+
+	return 0;
+}
+
+static const struct of_device_id umac_mdio_of_matches[] = {
+	{ .compatible = "hpe,gxp-umac-mdio", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, umac_mdio_of_matches);
+
+static struct platform_driver umac_driver = {
+	.driver	= {
+		.name    = "gxp-umac-mdio",
+		.of_match_table = of_match_ptr(umac_mdio_of_matches),
+	},
+	.probe   = umac_mdio_probe,
+	.remove  = umac_mdio_remove,
+};
+
+module_platform_driver(umac_driver);
+
+MODULE_AUTHOR("Nick Hawkins <nick.hawkins@hpe.com>");
+MODULE_DESCRIPTION("HPE GXP UMAC MDIO driver");
+MODULE_LICENSE("GPL");
-- 
2.17.1