Date:   Fri, 23 Oct 2020 16:45:43 +0800
From:   Xu Yilun <yilun.xu@...el.com>
To:     jesse.brandeburg@...el.com, anthony.l.nguyen@...el.com,
        davem@...emloft.net, kuba@...nel.org, mdf@...nel.org,
        lee.jones@...aro.org
Cc:     linux-kernel@...r.kernel.org, linux-fpga@...r.kernel.org,
        netdev@...r.kernel.org, trix@...hat.com, lgoncalv@...hat.com,
        yilun.xu@...el.com, hao.wu@...el.com
Subject: [RFC PATCH 4/6] ethernet: m10-retimer: add support for retimers on Intel MAX 10 BMC

This driver supports the ethernet retimers (Parkvale) for the Intel PAC
(Programmable Acceleration Card) N3000, which is a FPGA based Smart NIC.

Parkvale is an Intel(R) Ethernet serdes transceiver chip that supports up
to 100G transfer. On Intel PAC N3000 there are 2 Parkvale chips managed
by the Intel MAX 10 BMC firmware. They are configured in 4 ports 10G/25G
retimer mode. Host could query their link status via retimer interfaces
(Shared registers) on Intel MAX 10 BMC.

The driver adds the phy device for each port of the 2 retimer chips.
Since the phys are not accessed by the real MDIO bus, it creates a virtual
mdio bus for each NIC device instance, and a dedicated phy driver which
only provides the supported features and link state.

A DFL Ether Group driver will create net devices and connect to these
phys.

Signed-off-by: Xu Yilun <yilun.xu@...el.com>
---
 drivers/fpga/dfl-n3000-nios.c                      |  11 +-
 drivers/mfd/intel-m10-bmc.c                        |  18 ++
 drivers/net/ethernet/intel/Kconfig                 |  12 ++
 drivers/net/ethernet/intel/Makefile                |   2 +
 drivers/net/ethernet/intel/intel-m10-bmc-retimer.c | 229 +++++++++++++++++++++
 include/linux/mfd/intel-m10-bmc.h                  |  16 ++
 6 files changed, 286 insertions(+), 2 deletions(-)
 create mode 100644 drivers/net/ethernet/intel/intel-m10-bmc-retimer.c

diff --git a/drivers/fpga/dfl-n3000-nios.c b/drivers/fpga/dfl-n3000-nios.c
index 4983a2b..096931a 100644
--- a/drivers/fpga/dfl-n3000-nios.c
+++ b/drivers/fpga/dfl-n3000-nios.c
@@ -16,6 +16,7 @@
 #include <linux/io-64-nonatomic-lo-hi.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/mfd/intel-m10-bmc.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
 #include <linux/stddef.h>
@@ -159,6 +160,8 @@ struct n3000_nios {
 	struct regmap *regmap;
 	struct device *dev;
 	struct platform_device *altera_spi;
+	struct intel_m10bmc_platdata m10bmc_pdata;
+	struct intel_m10bmc_retimer_pdata m10bmc_retimer_pdata;
 };
 
 static ssize_t nios_fw_version_show(struct device *dev,
@@ -412,7 +415,8 @@ static struct spi_board_info m10_n3000_info = {
 	.chip_select = 0,
 };
 
-static int create_altera_spi_controller(struct n3000_nios *nn)
+static int create_altera_spi_controller(struct n3000_nios *nn,
+					struct device *retimer_master)
 {
 	struct altera_spi_platform_data pdata = { 0 };
 	struct platform_device_info pdevinfo = { 0 };
@@ -431,6 +435,9 @@ static int create_altera_spi_controller(struct n3000_nios *nn)
 	pdata.bits_per_word_mask =
 		SPI_BPW_RANGE_MASK(1, FIELD_GET(N3000_NS_PARAM_DATA_WIDTH, v));
 
+	nn->m10bmc_retimer_pdata.retimer_master = retimer_master;
+	nn->m10bmc_pdata.retimer = &nn->m10bmc_retimer_pdata;
+	m10_n3000_info.platform_data = &nn->m10bmc_pdata;
 	pdata.num_devices = 1;
 	pdata.devices = &m10_n3000_info;
 
@@ -549,7 +556,7 @@ static int n3000_nios_probe(struct dfl_device *ddev)
 	if (ret)
 		return ret;
 
-	ret = create_altera_spi_controller(nn);
+	ret = create_altera_spi_controller(nn, dfl_dev_get_base_dev(ddev));
 	if (ret)
 		dev_err(dev, "altera spi controller create failed: %d\n", ret);
 
diff --git a/drivers/mfd/intel-m10-bmc.c b/drivers/mfd/intel-m10-bmc.c
index b84579b..adbfb177 100644
--- a/drivers/mfd/intel-m10-bmc.c
+++ b/drivers/mfd/intel-m10-bmc.c
@@ -23,6 +23,21 @@ static struct mfd_cell m10bmc_pacn3000_subdevs[] = {
 	{ .name = "n3000bmc-secure" },
 };
 
+static void
+m10bmc_init_cells_platdata(struct intel_m10bmc_platdata *pdata,
+			   struct mfd_cell *cells, int n_cell)
+{
+	int i;
+
+	for (i = 0; i < n_cell; i++) {
+		if (!strcmp(cells[i].name, "n3000bmc-retimer")) {
+			cells[i].platform_data = pdata->retimer;
+			cells[i].pdata_size =
+				pdata->retimer ? sizeof(*pdata->retimer) : 0;
+		}
+	}
+}
+
 static struct regmap_config intel_m10bmc_regmap_config = {
 	.reg_bits = 32,
 	.val_bits = 32,
@@ -97,6 +112,7 @@ static int check_m10bmc_version(struct intel_m10bmc *ddata)
 
 static int intel_m10_bmc_spi_probe(struct spi_device *spi)
 {
+	struct intel_m10bmc_platdata *pdata = dev_get_platdata(&spi->dev);
 	const struct spi_device_id *id = spi_get_device_id(spi);
 	struct device *dev = &spi->dev;
 	struct mfd_cell *cells;
@@ -134,6 +150,8 @@ static int intel_m10_bmc_spi_probe(struct spi_device *spi)
 		return -ENODEV;
 	}
 
+	m10bmc_init_cells_platdata(pdata, cells, n_cell);
+
 	ret = devm_mfd_add_devices(dev, PLATFORM_DEVID_AUTO, cells, n_cell,
 				   NULL, 0, NULL);
 	if (ret)
diff --git a/drivers/net/ethernet/intel/Kconfig b/drivers/net/ethernet/intel/Kconfig
index 5aa8631..81c43d4 100644
--- a/drivers/net/ethernet/intel/Kconfig
+++ b/drivers/net/ethernet/intel/Kconfig
@@ -343,4 +343,16 @@ config IGC
 	  To compile this driver as a module, choose M here. The module
 	  will be called igc.
 
+config INTEL_M10_BMC_RETIMER
+	tristate "Intel(R) MAX 10 BMC ethernet retimer support"
+	depends on MFD_INTEL_M10_BMC
+	select PHYLIB
+        help
+          This driver supports the ethernet retimer (Parkvale) on
+	  Intel(R) MAX 10 BMC, which is used by Intel PAC N3000 FPGA based
+	  Smart NIC.
+
+	  To compile this driver as a module, choose M here. The module
+	  will be called intel-m10-bmc-retimer.
+
 endif # NET_VENDOR_INTEL
diff --git a/drivers/net/ethernet/intel/Makefile b/drivers/net/ethernet/intel/Makefile
index 3075290..5965447 100644
--- a/drivers/net/ethernet/intel/Makefile
+++ b/drivers/net/ethernet/intel/Makefile
@@ -16,3 +16,5 @@ obj-$(CONFIG_IXGB) += ixgb/
 obj-$(CONFIG_IAVF) += iavf/
 obj-$(CONFIG_FM10K) += fm10k/
 obj-$(CONFIG_ICE) += ice/
+
+obj-$(CONFIG_INTEL_M10_BMC_RETIMER) += intel-m10-bmc-retimer.o
diff --git a/drivers/net/ethernet/intel/intel-m10-bmc-retimer.c b/drivers/net/ethernet/intel/intel-m10-bmc-retimer.c
new file mode 100644
index 0000000..c7b0558
--- /dev/null
+++ b/drivers/net/ethernet/intel/intel-m10-bmc-retimer.c
@@ -0,0 +1,229 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Intel Max10 BMC Retimer Interface Driver
+ *
+ * Copyright (C) 2018-2020 Intel Corporation. All rights reserved.
+ *
+ */
+#include <linux/device.h>
+#include <linux/mfd/intel-m10-bmc.h>
+#include <linux/module.h>
+#include <linux/phy.h>
+#include <linux/platform_device.h>
+
+#define NUM_CHIP	2
+#define MAX_LINK	4
+
+#define BITS_MASK(nbits)	((1 << (nbits)) - 1)
+
+#define N3000BMC_RETIMER_DEV_NAME "n3000bmc-retimer"
+#define M10BMC_RETIMER_MII_NAME "m10bmc retimer mii"
+
+struct m10bmc_retimer {
+	struct device *dev;
+	struct intel_m10bmc *m10bmc;
+	int num_devs;
+	struct device *base_dev;
+	struct mii_bus *retimer_mii_bus;
+};
+
+#define RETIMER_LINK_STAT_BIT(retimer_id, link_id) \
+	BIT(((retimer_id) << 2) + (link_id))
+
+static u32 retimer_get_link(struct m10bmc_retimer *retimer, int index)
+{
+	unsigned int val;
+
+	if (m10bmc_sys_read(retimer->m10bmc, PKVL_LINK_STATUS, &val)) {
+		dev_err(retimer->dev, "fail to read PKVL_LINK_STATUS\n");
+		return 0;
+	}
+
+	if (val & BIT(index))
+		return 1;
+
+	return 0;
+}
+
+static int m10bmc_retimer_phy_match(struct phy_device *phydev)
+{
+	if (phydev->mdio.bus->name &&
+	    !strcmp(phydev->mdio.bus->name, M10BMC_RETIMER_MII_NAME)) {
+		return 1;
+	}
+
+	return 0;
+}
+
+static int m10bmc_retimer_phy_probe(struct phy_device *phydev)
+{
+	struct m10bmc_retimer *retimer = phydev->mdio.bus->priv;
+
+	phydev->priv = retimer;
+
+	return 0;
+}
+
+static void m10bmc_retimer_phy_remove(struct phy_device *phydev)
+{
+	if (phydev->attached_dev)
+		phy_disconnect(phydev);
+}
+
+static int m10bmc_retimer_read_status(struct phy_device *phydev)
+{
+	struct m10bmc_retimer *retimer = phydev->priv;
+
+	phydev->link = retimer_get_link(retimer, phydev->mdio.addr);
+
+	phydev->duplex = DUPLEX_FULL;
+
+	return 0;
+}
+
+static int m10bmc_retimer_get_features(struct phy_device *phydev)
+{
+	linkmode_set_bit(ETHTOOL_LINK_MODE_10000baseT_Full_BIT,
+			 phydev->supported);
+	linkmode_set_bit(ETHTOOL_LINK_MODE_10000baseSR_Full_BIT,
+			 phydev->supported);
+	linkmode_set_bit(ETHTOOL_LINK_MODE_10000baseLR_Full_BIT,
+			 phydev->supported);
+
+	linkmode_set_bit(ETHTOOL_LINK_MODE_25000baseCR_Full_BIT,
+			 phydev->supported);
+	linkmode_set_bit(ETHTOOL_LINK_MODE_25000baseSR_Full_BIT,
+			 phydev->supported);
+
+	linkmode_set_bit(ETHTOOL_LINK_MODE_40000baseCR4_Full_BIT,
+			 phydev->supported);
+	linkmode_set_bit(ETHTOOL_LINK_MODE_40000baseSR4_Full_BIT,
+			 phydev->supported);
+	linkmode_set_bit(ETHTOOL_LINK_MODE_40000baseLR4_Full_BIT,
+			 phydev->supported);
+
+	linkmode_set_bit(ETHTOOL_LINK_MODE_Asym_Pause_BIT, phydev->supported);
+
+	return 0;
+}
+
+static struct phy_driver m10bmc_retimer_phy_driver = {
+	.phy_id			= 0xffffffff,
+	.phy_id_mask		= 0xffffffff,
+	.name			= "m10bmc retimer PHY",
+	.match_phy_device	= m10bmc_retimer_phy_match,
+	.probe			= m10bmc_retimer_phy_probe,
+	.remove			= m10bmc_retimer_phy_remove,
+	.read_status		= m10bmc_retimer_read_status,
+	.get_features		= m10bmc_retimer_get_features,
+	.read_mmd		= genphy_read_mmd_unsupported,
+	.write_mmd		= genphy_write_mmd_unsupported,
+};
+
+static int m10bmc_retimer_read(struct mii_bus *bus, int addr, int regnum)
+{
+	struct m10bmc_retimer *retimer = bus->priv;
+
+	if (addr < retimer->num_devs &&
+	    (regnum == MII_PHYSID1 || regnum == MII_PHYSID2))
+		return 0;
+
+	return 0xffff;
+}
+
+static int m10bmc_retimer_write(struct mii_bus *bus, int addr, int regnum, u16 val)
+{
+	return 0;
+}
+
+static int m10bmc_retimer_mii_bus_init(struct m10bmc_retimer *retimer)
+{
+	struct mii_bus *bus;
+	int ret;
+
+	bus = devm_mdiobus_alloc(retimer->dev);
+	if (!bus)
+		return -ENOMEM;
+
+	bus->priv = (void *)retimer;
+	bus->name = M10BMC_RETIMER_MII_NAME;
+	bus->read = m10bmc_retimer_read;
+	bus->write = m10bmc_retimer_write;
+	snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii",
+		 dev_name(retimer->base_dev));
+	bus->parent = retimer->dev;
+	bus->phy_mask = ~(BITS_MASK(retimer->num_devs));
+
+	ret = mdiobus_register(bus);
+	if (ret)
+		return ret;
+
+	retimer->retimer_mii_bus = bus;
+
+	return 0;
+}
+
+static void m10bmc_retimer_mii_bus_uinit(struct m10bmc_retimer *retimer)
+{
+	mdiobus_unregister(retimer->retimer_mii_bus);
+}
+
+static int intel_m10bmc_retimer_probe(struct platform_device *pdev)
+{
+	struct intel_m10bmc_retimer_pdata *pdata = dev_get_platdata(&pdev->dev);
+	struct intel_m10bmc *m10bmc = dev_get_drvdata(pdev->dev.parent);
+	struct m10bmc_retimer *retimer;
+
+	retimer = devm_kzalloc(&pdev->dev, sizeof(*retimer), GFP_KERNEL);
+	if (!retimer)
+		return -ENOMEM;
+
+	dev_set_drvdata(&pdev->dev, retimer);
+
+	retimer->dev = &pdev->dev;
+	retimer->m10bmc = m10bmc;
+	retimer->base_dev = pdata->retimer_master;
+	retimer->num_devs = NUM_CHIP * MAX_LINK;
+
+	return m10bmc_retimer_mii_bus_init(retimer);
+}
+
+static int intel_m10bmc_retimer_remove(struct platform_device *pdev)
+{
+	struct m10bmc_retimer *retimer = dev_get_drvdata(&pdev->dev);
+
+	m10bmc_retimer_mii_bus_uinit(retimer);
+
+	return 0;
+}
+
+static struct platform_driver intel_m10bmc_retimer_driver = {
+	.probe = intel_m10bmc_retimer_probe,
+	.remove = intel_m10bmc_retimer_remove,
+	.driver = {
+		.name = N3000BMC_RETIMER_DEV_NAME,
+	},
+};
+
+static int __init intel_m10bmc_retimer_init(void)
+{
+	int ret;
+
+	ret = phy_driver_register(&m10bmc_retimer_phy_driver, THIS_MODULE);
+	if (ret)
+		return ret;
+
+	return platform_driver_register(&intel_m10bmc_retimer_driver);
+}
+module_init(intel_m10bmc_retimer_init);
+
+static void __exit intel_m10bmc_retimer_exit(void)
+{
+	platform_driver_unregister(&intel_m10bmc_retimer_driver);
+	phy_driver_unregister(&m10bmc_retimer_phy_driver);
+}
+module_exit(intel_m10bmc_retimer_exit);
+
+MODULE_ALIAS("platform:" N3000BMC_RETIMER_DEV_NAME);
+MODULE_AUTHOR("Intel Corporation");
+MODULE_DESCRIPTION("Intel MAX 10 BMC retimer driver");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/mfd/intel-m10-bmc.h b/include/linux/mfd/intel-m10-bmc.h
index c8ef2f1..3d9d22c 100644
--- a/include/linux/mfd/intel-m10-bmc.h
+++ b/include/linux/mfd/intel-m10-bmc.h
@@ -21,6 +21,22 @@
 #define M10BMC_VER_PCB_INFO_MSK		GENMASK(31, 24)
 #define M10BMC_VER_LEGACY_INVALID	0xffffffff
 
+/* PKVL related registers, in system register region */
+#define PKVL_LINK_STATUS		0x164
+
+/**
+ * struct intel_m10bmc_retimer_pdata - subdev retimer platform data
+ *
+ * @retimer_master: the NIC device which connects to the retimers on m10bmc
+ */
+struct intel_m10bmc_retimer_pdata {
+	struct device *retimer_master;
+};
+
+struct intel_m10bmc_platdata {
+	struct intel_m10bmc_retimer_pdata *retimer;
+};
+
 /**
  * struct intel_m10bmc - Intel MAX 10 BMC parent driver data structure
  * @dev: this device
-- 
2.7.4

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