ethernet/arc/arc_emac - Add new driver

Driver for non-standard on-chip ethernet device ARC EMAC 10/100,
instantiated in some legacy ARC (Synopsys) FPGA Boards such as
ARCAngel4/ML50x.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>

Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Francois Romieu <romieu@fr.zoreil.com>
Cc: Joe Perches <joe@perches.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Mischa Jonker <mjonker@synopsys.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: linux-kernel@vger.kernel.org
Cc: devicetree-discuss@lists.ozlabs.org
Cc: Florian Fainelli <florian@openwrt.org>
Cc: David Laight <david.laight@aculab.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 152 insertions, 0 deletions

diff --git a/drivers/net/ethernet/arc/emac_mdio.c b/drivers/net/ethernet/arc/emac_mdio.c
new file mode 100644
index 000000000000..26ba2423f33a
--- /dev/null
+++ b/drivers/net/ethernet/arc/emac_mdio.c
@@ -0,0 +1,152 @@
+/*
+ * Copyright (C) 2004-2013 Synopsys, Inc. (www.synopsys.com)
+ *
+ * MDIO implementation for ARC EMAC
+ */
+
+#include <linux/delay.h>
+#include <linux/of_mdio.h>
+#include <linux/platform_device.h>
+
+#include "emac.h"
+
+/* Number of seconds we wait for "MDIO complete" flag to appear */
+#define ARC_MDIO_COMPLETE_POLL_COUNT	1
+
+/**
+ * arc_mdio_complete_wait - Waits until MDIO transaction is completed.
+ * @priv:	Pointer to ARC EMAC private data structure.
+ *
+ * returns:	0 on success, -ETIMEDOUT on a timeout.
+ */
+static int arc_mdio_complete_wait(struct arc_emac_priv *priv)
+{
+	unsigned int i;
+
+	for (i = 0; i < ARC_MDIO_COMPLETE_POLL_COUNT * 40; i++) {
+		unsigned int status = arc_reg_get(priv, R_STATUS);
+
+		status &= MDIO_MASK;
+
+		if (status) {
+			/* Reset "MDIO complete" flag */
+			arc_reg_set(priv, R_STATUS, status);
+			return 0;
+		}
+
+		msleep(25);
+	}
+
+	return -ETIMEDOUT;
+}
+
+/**
+ * arc_mdio_read - MDIO interface read function.
+ * @bus:	Pointer to MII bus structure.
+ * @phy_addr:	Address of the PHY device.
+ * @reg_num:	PHY register to read.
+ *
+ * returns:	The register contents on success, -ETIMEDOUT on a timeout.
+ *
+ * Reads the contents of the requested register from the requested PHY
+ * address.
+ */
+static int arc_mdio_read(struct mii_bus *bus, int phy_addr, int reg_num)
+{
+	struct arc_emac_priv *priv = bus->priv;
+	unsigned int value;
+	int error;
+
+	arc_reg_set(priv, R_MDIO,
+		    0x60020000 | (phy_addr << 23) | (reg_num << 18));
+
+	error = arc_mdio_complete_wait(priv);
+	if (error < 0)
+		return error;
+
+	value = arc_reg_get(priv, R_MDIO) & 0xffff;
+
+	dev_dbg(priv->dev, "arc_mdio_read(phy_addr=%i, reg_num=%x) = %x\n",
+		phy_addr, reg_num, value);
+
+	return value;
+}
+
+/**
+ * arc_mdio_write - MDIO interface write function.
+ * @bus:	Pointer to MII bus structure.
+ * @phy_addr:	Address of the PHY device.
+ * @reg_num:	PHY register to write to.
+ * @value:	Value to be written into the register.
+ *
+ * returns:	0 on success, -ETIMEDOUT on a timeout.
+ *
+ * Writes the value to the requested register.
+ */
+static int arc_mdio_write(struct mii_bus *bus, int phy_addr,
+			  int reg_num, u16 value)
+{
+	struct arc_emac_priv *priv = bus->priv;
+
+	dev_dbg(priv->dev,
+		"arc_mdio_write(phy_addr=%i, reg_num=%x, value=%x)\n",
+		phy_addr, reg_num, value);
+
+	arc_reg_set(priv, R_MDIO,
+		     0x50020000 | (phy_addr << 23) | (reg_num << 18) | value);
+
+	return arc_mdio_complete_wait(priv);
+}
+
+/**
+ * arc_mdio_probe - MDIO probe function.
+ * @pdev:	Pointer to platform device.
+ * @priv:	Pointer to ARC EMAC private data structure.
+ *
+ * returns:	0 on success, -ENOMEM when mdiobus_alloc
+ * (to allocate memory for MII bus structure) fails.
+ *
+ * Sets up and registers the MDIO interface.
+ */
+int arc_mdio_probe(struct platform_device *pdev, struct arc_emac_priv *priv)
+{
+	struct mii_bus *bus;
+	int error;
+
+	bus = mdiobus_alloc();
+	if (!bus)
+		return -ENOMEM;
+
+	priv->bus = bus;
+	bus->priv = priv;
+	bus->parent = priv->dev;
+	bus->name = "Synopsys MII Bus",
+	bus->read = &arc_mdio_read;
+	bus->write = &arc_mdio_write;
+
+	snprintf(bus->id, MII_BUS_ID_SIZE, "%s", pdev->name);
+
+	error = of_mdiobus_register(bus, pdev->dev.of_node);
+	if (error) {
+		dev_err(priv->dev, "cannot register MDIO bus %s\n", bus->name);
+		mdiobus_free(bus);
+		return error;
+	}
+
+	return 0;
+}
+
+/**
+ * arc_mdio_remove - MDIO remove function.
+ * @priv:	Pointer to ARC EMAC private data structure.
+ *
+ * Unregisters the MDIO and frees any associate memory for MII bus.
+ */
+int arc_mdio_remove(struct arc_emac_priv *priv)
+{
+	mdiobus_unregister(priv->bus);
+	mdiobus_free(priv->bus);
+	priv->bus = NULL;
+
+	return 0;
+}