drivers/net/ethernet/xilinx: added Xilinx AXI Ethernet driver

This driver adds support for Xilinx 10/100/1000 AXI Ethernet.

It can be used, for instance, on Xilinx boards with a Microblaze
architecture like the ML605.

The patch is against the latest net-next tree and checkpatch clean.
Signed-off-by: Ariane Keller <ariane.keller@tik.ee.ethz.ch>
Signed-off-by: Daniel Borkmann <daniel.borkmann@tik.ee.ethz.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

MAINTAINERS

@@ -7469,6 +7469,12 @@ S:	Supported
 F:	Documentation/filesystems/xfs.txt
 F:	fs/xfs/
 
+XILINX AXI ETHERNET DRIVER
+M:	Ariane Keller <ariane.keller@tik.ee.ethz.ch>
+M:	Daniel Borkmann <daniel.borkmann@tik.ee.ethz.ch>
+S:	Maintained
+F:	drivers/net/ethernet/xilinx/xilinx_axienet*
+
 XILINX SYSTEMACE DRIVER
 M:	Grant Likely <grant.likely@secretlab.ca>
 W:	http://www.secretlab.ca/

drivers/net/ethernet/xilinx/Kconfig

@@ -25,6 +25,14 @@ config XILINX_EMACLITE
 	---help---
 	  This driver supports the 10/100 Ethernet Lite from Xilinx.
 
+config XILINX_AXI_EMAC
+	tristate "Xilinx 10/100/1000 AXI Ethernet support"
+	depends on (PPC32 || MICROBLAZE)
+	select PHYLIB
+	---help---
+	  This driver supports the 10/100/1000 Ethernet from Xilinx for the
+	  AXI bus interface used in Xilinx Virtex FPGAs.
+
 config XILINX_LL_TEMAC
 	tristate "Xilinx LL TEMAC (LocalLink Tri-mode Ethernet MAC) driver"
 	depends on (PPC || MICROBLAZE)

drivers/net/ethernet/xilinx/Makefile

@@ -5,3 +5,5 @@
 ll_temac-objs := ll_temac_main.o ll_temac_mdio.o
 obj-$(CONFIG_XILINX_LL_TEMAC) += ll_temac.o
 obj-$(CONFIG_XILINX_EMACLITE) += xilinx_emaclite.o
+xilinx_emac-objs := xilinx_axienet_main.o xilinx_axienet_mdio.o
+obj-$(CONFIG_XILINX_AXI_EMAC) += xilinx_emac.o

drivers/net/ethernet/xilinx/xilinx_axienet_mdio.c

+/*
+ * MDIO bus driver for the Xilinx Axi Ethernet device
+ *
+ * Copyright (c) 2009 Secret Lab Technologies, Ltd.
+ * Copyright (c) 2010 Xilinx, Inc. All rights reserved.
+ * Copyright (c) 2012 Daniel Borkmann, <daniel.borkmann@tik.ee.ethz.ch>
+ * Copyright (c) 2012 Ariane Keller, <ariane.keller@tik.ee.ethz.ch>
+ */
+
+#include <linux/of_address.h>
+#include <linux/of_mdio.h>
+#include <linux/jiffies.h>
+
+#include "xilinx_axienet.h"
+
+#define MAX_MDIO_FREQ		2500000 /* 2.5 MHz */
+#define DEFAULT_CLOCK_DIVISOR	XAE_MDIO_DIV_DFT
+
+/* Wait till MDIO interface is ready to accept a new transaction.*/
+int axienet_mdio_wait_until_ready(struct axienet_local *lp)
+{
+	long end = jiffies + 2;
+	while (!(axienet_ior(lp, XAE_MDIO_MCR_OFFSET) &
+		 XAE_MDIO_MCR_READY_MASK)) {
+		if (end - jiffies <= 0) {
+			WARN_ON(1);
+			return -ETIMEDOUT;
+		}
+		udelay(1);
+	}
+	return 0;
+}
+
+/**
+ * axienet_mdio_read - MDIO interface read function
+ * @bus:	Pointer to mii bus structure
+ * @phy_id:	Address of the PHY device
+ * @reg:	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 by first writing the details into MCR register. After a while
+ * the register MRD is read to obtain the PHY register content.
+ */
+static int axienet_mdio_read(struct mii_bus *bus, int phy_id, int reg)
+{
+	u32 rc;
+	int ret;
+	struct axienet_local *lp = bus->priv;
+
+	ret = axienet_mdio_wait_until_ready(lp);
+	if (ret < 0)
+		return ret;
+
+	axienet_iow(lp, XAE_MDIO_MCR_OFFSET,
+		    (((phy_id << XAE_MDIO_MCR_PHYAD_SHIFT) &
+		      XAE_MDIO_MCR_PHYAD_MASK) |
+		     ((reg << XAE_MDIO_MCR_REGAD_SHIFT) &
+		      XAE_MDIO_MCR_REGAD_MASK) |
+		     XAE_MDIO_MCR_INITIATE_MASK |
+		     XAE_MDIO_MCR_OP_READ_MASK));
+
+	ret = axienet_mdio_wait_until_ready(lp);
+	if (ret < 0)
+		return ret;
+
+	rc = axienet_ior(lp, XAE_MDIO_MRD_OFFSET) & 0x0000FFFF;
+
+	dev_dbg(lp->dev, "axienet_mdio_read(phy_id=%i, reg=%x) == %x\n",
+		phy_id, reg, rc);
+
+	return rc;
+}
+
+/**
+ * axienet_mdio_write - MDIO interface write function
+ * @bus:	Pointer to mii bus structure
+ * @phy_id:	Address of the PHY device
+ * @reg:	PHY register to write to
+ * @val:	Value to be written into the register
+ *
+ * returns:	0 on success, -ETIMEDOUT on a timeout
+ *
+ * Writes the value to the requested register by first writing the value
+ * into MWD register. The the MCR register is then appropriately setup
+ * to finish the write operation.
+ */
+static int axienet_mdio_write(struct mii_bus *bus, int phy_id, int reg,
+			      u16 val)
+{
+	int ret;
+	struct axienet_local *lp = bus->priv;
+
+	dev_dbg(lp->dev, "axienet_mdio_write(phy_id=%i, reg=%x, val=%x)\n",
+		phy_id, reg, val);
+
+	ret = axienet_mdio_wait_until_ready(lp);
+	if (ret < 0)
+		return ret;
+
+	axienet_iow(lp, XAE_MDIO_MWD_OFFSET, (u32) val);
+	axienet_iow(lp, XAE_MDIO_MCR_OFFSET,
+		    (((phy_id << XAE_MDIO_MCR_PHYAD_SHIFT) &
+		      XAE_MDIO_MCR_PHYAD_MASK) |
+		     ((reg << XAE_MDIO_MCR_REGAD_SHIFT) &
+		      XAE_MDIO_MCR_REGAD_MASK) |
+		     XAE_MDIO_MCR_INITIATE_MASK |
+		     XAE_MDIO_MCR_OP_WRITE_MASK));
+
+	ret = axienet_mdio_wait_until_ready(lp);
+	if (ret < 0)
+		return ret;
+	return 0;
+}
+
+/**
+ * axienet_mdio_setup - MDIO setup function
+ * @lp:		Pointer to axienet local data structure.
+ * @np:		Pointer to device node
+ *
+ * returns:	0 on success, -ETIMEDOUT on a timeout, -ENOMEM when
+ *		mdiobus_alloc (to allocate memory for mii bus structure) fails.
+ *
+ * Sets up the MDIO interface by initializing the MDIO clock and enabling the
+ * MDIO interface in hardware. Register the MDIO interface.
+ **/
+int axienet_mdio_setup(struct axienet_local *lp, struct device_node *np)
+{
+	int ret;
+	u32 clk_div, host_clock;
+	u32 *property_p;
+	struct mii_bus *bus;
+	struct resource res;
+	struct device_node *np1;
+
+	/* clk_div can be calculated by deriving it from the equation:
+	 * fMDIO = fHOST / ((1 + clk_div) * 2)
+	 *
+	 * Where fMDIO <= 2500000, so we get:
+	 * fHOST / ((1 + clk_div) * 2) <= 2500000
+	 *
+	 * Then we get:
+	 * 1 / ((1 + clk_div) * 2) <= (2500000 / fHOST)
+	 *
+	 * Then we get:
+	 * 1 / (1 + clk_div) <= ((2500000 * 2) / fHOST)
+	 *
+	 * Then we get:
+	 * 1 / (1 + clk_div) <= (5000000 / fHOST)
+	 *
+	 * So:
+	 * (1 + clk_div) >= (fHOST / 5000000)
+	 *
+	 * And finally:
+	 * clk_div >= (fHOST / 5000000) - 1
+	 *
+	 * fHOST can be read from the flattened device tree as property
+	 * "clock-frequency" from the CPU
+	 */
+
+	np1 = of_find_node_by_name(NULL, "cpu");
+	if (!np1) {
+		printk(KERN_WARNING "%s(): Could not find CPU device node.",
+		       __func__);
+		printk(KERN_WARNING "Setting MDIO clock divisor to "
+		       "default %d\n", DEFAULT_CLOCK_DIVISOR);
+		clk_div = DEFAULT_CLOCK_DIVISOR;
+		goto issue;
+	}
+	property_p = (u32 *) of_get_property(np1, "clock-frequency", NULL);
+	if (!property_p) {
+		printk(KERN_WARNING "%s(): Could not find CPU property: "
+		       "clock-frequency.", __func__);
+		printk(KERN_WARNING "Setting MDIO clock divisor to "
+		       "default %d\n", DEFAULT_CLOCK_DIVISOR);
+		clk_div = DEFAULT_CLOCK_DIVISOR;
+		goto issue;
+	}
+
+	host_clock = be32_to_cpup(property_p);
+	clk_div = (host_clock / (MAX_MDIO_FREQ * 2)) - 1;
+	/* If there is any remainder from the division of
+	 * fHOST / (MAX_MDIO_FREQ * 2), then we need to add
+	 * 1 to the clock divisor or we will surely be above 2.5 MHz */
+	if (host_clock % (MAX_MDIO_FREQ * 2))
+		clk_div++;
+
+	printk(KERN_DEBUG "%s(): Setting MDIO clock divisor to %u based "
+	       "on %u Hz host clock.\n", __func__, clk_div, host_clock);
+
+	of_node_put(np1);
+issue:
+	axienet_iow(lp, XAE_MDIO_MC_OFFSET,
+		    (((u32) clk_div) | XAE_MDIO_MC_MDIOEN_MASK));
+
+	ret = axienet_mdio_wait_until_ready(lp);
+	if (ret < 0)
+		return ret;
+
+	bus = mdiobus_alloc();
+	if (!bus)
+		return -ENOMEM;
+
+	np1 = of_get_parent(lp->phy_node);
+	of_address_to_resource(np1, 0, &res);
+	snprintf(bus->id, MII_BUS_ID_SIZE, "%.8llx",
+		 (unsigned long long) res.start);
+
+	bus->priv = lp;
+	bus->name = "Xilinx Axi Ethernet MDIO";
+	bus->read = axienet_mdio_read;
+	bus->write = axienet_mdio_write;
+	bus->parent = lp->dev;
+	bus->irq = lp->mdio_irqs; /* preallocated IRQ table */
+	lp->mii_bus = bus;
+
+	ret = of_mdiobus_register(bus, np1);
+	if (ret) {
+		mdiobus_free(bus);
+		return ret;
+	}
+	return 0;
+}
+
+/**
+ * axienet_mdio_teardown - MDIO remove function
+ * @lp:		Pointer to axienet local data structure.
+ *
+ * Unregisters the MDIO and frees any associate memory for mii bus.
+ */
+void axienet_mdio_teardown(struct axienet_local *lp)
+{
+	mdiobus_unregister(lp->mii_bus);
+	kfree(lp->mii_bus->irq);
+	mdiobus_free(lp->mii_bus);
+	lp->mii_bus = NULL;
+}