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From:   Claudiu Manoil <claudiu.manoil@nxp.com>
To:     "David S . Miller" <davem@davemloft.net>
Cc:     andrew@lunn.ch, Rob Herring <robh+dt@kernel.org>,
        Li Yang <leoyang.li@nxp.com>, alexandru.marginean@nxp.com,
        netdev@vger.kernel.org, devicetree@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH net-next v2 2/4] enetc: Add mdio bus driver for the PCIe MDIO endpoint
Date:   Thu, 25 Jul 2019 14:19:26 +0300
Message-Id: <1564053568-20522-3-git-send-email-claudiu.manoil@nxp.com>
In-Reply-To: <1564053568-20522-1-git-send-email-claudiu.manoil@nxp.com>
References: <1564053568-20522-1-git-send-email-claudiu.manoil@nxp.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

ENETC ports can manage the MDIO bus via local register
interface.  However there's also a centralized way
to manage the MDIO bus, via the MDIO PCIe endpoint
device integrated by the same root complex that also
integrates the ENETC ports (eth controllers).

Depending on board design and use case, centralized
access to MDIO may be better than using local ENETC
port registers.  For instance, on the LS1028A QDS board
where MDIO muxing is requiered.  Also, the LS1028A on-chip
switch doesn't have a local MDIO register interface.

The current patch registers the above PCIe enpoint as a
separate MDIO bus and provides a driver for it by re-using
the code used for local MDIO access.  It also allows the
ENETC port PHYs to be managed by this driver if the local
"mdio" node is missing from the ENETC port node.

Signed-off-by: Claudiu Manoil <claudiu.manoil@nxp.com>
---
v1 - fixed mdio bus allocation
   - requested only BAR0 region, as it's the only one used by the driver
v2 - reworked accessors as per Andrew Lunn's request

 .../net/ethernet/freescale/enetc/enetc_mdio.c | 98 +++++++++++++++++++
 .../net/ethernet/freescale/enetc/enetc_pf.c   |  5 +-
 2 files changed, 102 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/freescale/enetc/enetc_mdio.c b/drivers/net/ethernet/freescale/enetc/enetc_mdio.c
index 05094601ece8..56ad94a3504c 100644
--- a/drivers/net/ethernet/freescale/enetc/enetc_mdio.c
+++ b/drivers/net/ethernet/freescale/enetc/enetc_mdio.c
@@ -195,3 +195,101 @@ void enetc_mdio_remove(struct enetc_pf *pf)
 	if (pf->mdio)
 		mdiobus_unregister(pf->mdio);
 }
+
+#define ENETC_MDIO_DEV_ID	0xee01
+#define ENETC_MDIO_DEV_NAME	"FSL PCIe IE Central MDIO"
+#define ENETC_MDIO_BUS_NAME	ENETC_MDIO_DEV_NAME " Bus"
+#define ENETC_MDIO_DRV_NAME	ENETC_MDIO_DEV_NAME " driver"
+#define ENETC_MDIO_DRV_ID	"fsl_enetc_mdio"
+
+static int enetc_pci_mdio_probe(struct pci_dev *pdev,
+				const struct pci_device_id *ent)
+{
+	struct enetc_mdio_priv *mdio_priv;
+	struct device *dev = &pdev->dev;
+	struct enetc_hw *hw;
+	struct mii_bus *bus;
+	int err;
+
+	hw = devm_kzalloc(dev, sizeof(*hw), GFP_KERNEL);
+	if (!hw)
+		return -ENOMEM;
+
+	bus = devm_mdiobus_alloc_size(dev, sizeof(*mdio_priv));
+	if (!bus)
+		return -ENOMEM;
+
+	bus->name = ENETC_MDIO_BUS_NAME;
+	bus->read = enetc_mdio_read;
+	bus->write = enetc_mdio_write;
+	bus->parent = dev;
+	mdio_priv = bus->priv;
+	mdio_priv->hw = hw;
+	snprintf(bus->id, MII_BUS_ID_SIZE, "%s", dev_name(dev));
+
+	pcie_flr(pdev);
+	err = pci_enable_device_mem(pdev);
+	if (err) {
+		dev_err(dev, "device enable failed\n");
+		return err;
+	}
+
+	err = pci_request_region(pdev, 0, ENETC_MDIO_DRV_ID);
+	if (err) {
+		dev_err(dev, "pci_request_region failed\n");
+		goto err_pci_mem_reg;
+	}
+
+	hw->port = pci_iomap(pdev, 0, 0);
+	if (!bus->priv) {
+		err = -ENXIO;
+		dev_err(dev, "iomap failed\n");
+		goto err_ioremap;
+	}
+
+	err = of_mdiobus_register(bus, dev->of_node);
+	if (err)
+		goto err_mdiobus_reg;
+
+	pci_set_drvdata(pdev, bus);
+
+	return 0;
+
+err_mdiobus_reg:
+	iounmap(mdio_priv->hw->port);
+err_ioremap:
+	pci_release_mem_regions(pdev);
+err_pci_mem_reg:
+	pci_disable_device(pdev);
+
+	return err;
+}
+
+static void enetc_pci_mdio_remove(struct pci_dev *pdev)
+{
+	struct mii_bus *bus = pci_get_drvdata(pdev);
+	struct enetc_mdio_priv *mdio_priv;
+
+	mdiobus_unregister(bus);
+	mdio_priv = bus->priv;
+	iounmap(mdio_priv->hw->port);
+	pci_release_mem_regions(pdev);
+	pci_disable_device(pdev);
+}
+
+static const struct pci_device_id enetc_pci_mdio_id_table[] = {
+	{ PCI_DEVICE(PCI_VENDOR_ID_FREESCALE, ENETC_MDIO_DEV_ID) },
+	{ 0, } /* End of table. */
+};
+MODULE_DEVICE_TABLE(pci, enetc_mdio_id_table);
+
+static struct pci_driver enetc_pci_mdio_driver = {
+	.name = ENETC_MDIO_DRV_ID,
+	.id_table = enetc_pci_mdio_id_table,
+	.probe = enetc_pci_mdio_probe,
+	.remove = enetc_pci_mdio_remove,
+};
+module_pci_driver(enetc_pci_mdio_driver);
+
+MODULE_DESCRIPTION(ENETC_MDIO_DRV_NAME);
+MODULE_LICENSE("Dual BSD/GPL");
diff --git a/drivers/net/ethernet/freescale/enetc/enetc_pf.c b/drivers/net/ethernet/freescale/enetc/enetc_pf.c
index 258b3cb38a6f..7d6513ff8507 100644
--- a/drivers/net/ethernet/freescale/enetc/enetc_pf.c
+++ b/drivers/net/ethernet/freescale/enetc/enetc_pf.c
@@ -750,6 +750,7 @@ static int enetc_of_get_phy(struct enetc_ndev_priv *priv)
 {
 	struct enetc_pf *pf = enetc_si_priv(priv->si);
 	struct device_node *np = priv->dev->of_node;
+	struct device_node *mdio_np;
 	int err;
 
 	if (!np) {
@@ -773,7 +774,9 @@ static int enetc_of_get_phy(struct enetc_ndev_priv *priv)
 		priv->phy_node = of_node_get(np);
 	}
 
-	if (!of_phy_is_fixed_link(np)) {
+	mdio_np = of_get_child_by_name(np, "mdio");
+	if (mdio_np) {
+		of_node_put(mdio_np);
 		err = enetc_mdio_probe(pf);
 		if (err) {
 			of_node_put(priv->phy_node);
-- 
2.17.1