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>

Documentation/devicetree/bindings/net/arc_emac.txt

+* Synopsys ARC EMAC 10/100 Ethernet driver (EMAC)
+
+Required properties:
+- compatible: Should be "snps,arc-emac"
+- reg: Address and length of the register set for the device
+- interrupts: Should contain the EMAC interrupts
+- clock-frequency: CPU frequency. It is needed to calculate and set polling
+period of EMAC.
+- max-speed: Maximum supported data-rate in Mbit/s. In some HW configurations
+bandwidth of external memory controller might be a limiting factor. That's why
+it's required to specify which data-rate is supported on current SoC or FPGA.
+For example if only 10 Mbit/s is supported (10BASE-T) set "10". If 100 Mbit/s is
+supported (100BASE-TX) set "100".
+- phy: PHY device attached to the EMAC via MDIO bus
+
+Child nodes of the driver are the individual PHY devices connected to the
+MDIO bus. They must have a "reg" property given the PHY address on the MDIO bus.
+
+Optional properties:
+- mac-address: 6 bytes, mac address
+
+Examples:
+
+	ethernet@c0fc2000 {
+		compatible = "snps,arc-emac";
+		reg = <0xc0fc2000 0x3c>;
+		interrupts = <6>;
+		mac-address = [ 00 11 22 33 44 55 ];
+		clock-frequency = <80000000>;
+		max-speed = <100>;
+		phy = <&phy0>;
+
+		#address-cells = <1>;
+		#size-cells = <0>;
+		phy0: ethernet-phy@0 {
+			reg = <1>;
+		};
+	};

drivers/net/ethernet/Kconfig

@@ -24,6 +24,7 @@ source "drivers/net/ethernet/allwinner/Kconfig"
 source "drivers/net/ethernet/alteon/Kconfig"
 source "drivers/net/ethernet/amd/Kconfig"
 source "drivers/net/ethernet/apple/Kconfig"
+source "drivers/net/ethernet/arc/Kconfig"
 source "drivers/net/ethernet/atheros/Kconfig"
 source "drivers/net/ethernet/cadence/Kconfig"
 source "drivers/net/ethernet/adi/Kconfig"

drivers/net/ethernet/Makefile

@@ -10,6 +10,7 @@ obj-$(CONFIG_NET_VENDOR_ALLWINNER) += allwinner/
 obj-$(CONFIG_NET_VENDOR_ALTEON) += alteon/
 obj-$(CONFIG_NET_VENDOR_AMD) += amd/
 obj-$(CONFIG_NET_VENDOR_APPLE) += apple/
+obj-$(CONFIG_NET_VENDOR_ARC) += arc/
 obj-$(CONFIG_NET_VENDOR_ATHEROS) += atheros/
 obj-$(CONFIG_NET_CADENCE) += cadence/
 obj-$(CONFIG_NET_BFIN) += adi/

drivers/net/ethernet/arc/Kconfig

+#
+# ARC EMAC network device configuration
+#
+
+config NET_VENDOR_ARC
+	bool "ARC devices"
+	default y
+	---help---
+	  If you have a network (Ethernet) card belonging to this class, say Y
+	  and read the Ethernet-HOWTO, available from
+	  <http://www.tldp.org/docs.html#howto>.
+
+	  Note that the answer to this question doesn't directly affect the
+	  kernel: saying N will just cause the configurator to skip all
+	  the questions about ARC cards. If you say Y, you will be asked for
+	  your specific card in the following questions.
+
+if NET_VENDOR_ARC
+
+config ARC_EMAC
+	tristate "ARC EMAC support"
+	select MII
+	select PHYLIB
+	depends on OF_IRQ
+	depends on OF_NET
+	---help---
+	  On some legacy ARC (Synopsys) FPGA boards such as ARCAngel4/ML50x
+	  non-standard on-chip ethernet device ARC EMAC 10/100 is used.
+	  Say Y here if you have such a board.  If unsure, say N.
+
+endif # NET_VENDOR_ARC

drivers/net/ethernet/arc/Makefile

+#
+# Makefile for the ARC network device drivers.
+#
+
+arc_emac-objs := emac_main.o emac_mdio.o
+obj-$(CONFIG_ARC_EMAC) += arc_emac.o

drivers/net/ethernet/arc/emac.h

+/*
+ * Copyright (C) 2004-2013 Synopsys, Inc. (www.synopsys.com)
+ *
+ * Registers and bits definitions of ARC EMAC
+ */
+
+#ifndef ARC_EMAC_H
+#define ARC_EMAC_H
+
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <linux/netdevice.h>
+#include <linux/phy.h>
+
+/* STATUS and ENABLE Register bit masks */
+#define TXINT_MASK	(1<<0)	/* Transmit interrupt */
+#define RXINT_MASK	(1<<1)	/* Receive interrupt */
+#define ERR_MASK	(1<<2)	/* Error interrupt */
+#define TXCH_MASK	(1<<3)	/* Transmit chaining error interrupt */
+#define MSER_MASK	(1<<4)	/* Missed packet counter error */
+#define RXCR_MASK	(1<<8)	/* RXCRCERR counter rolled over  */
+#define RXFR_MASK	(1<<9)	/* RXFRAMEERR counter rolled over */
+#define RXFL_MASK	(1<<10)	/* RXOFLOWERR counter rolled over */
+#define MDIO_MASK	(1<<12)	/* MDIO complete interrupt */
+#define TXPL_MASK	(1<<31)	/* Force polling of BD by EMAC */
+
+/* CONTROL Register bit masks */
+#define EN_MASK		(1<<0)	/* VMAC enable */
+#define TXRN_MASK	(1<<3)	/* TX enable */
+#define RXRN_MASK	(1<<4)	/* RX enable */
+#define DSBC_MASK	(1<<8)	/* Disable receive broadcast */
+#define ENFL_MASK	(1<<10)	/* Enable Full-duplex */
+#define PROM_MASK	(1<<11)	/* Promiscuous mode */
+
+/* Buffer descriptor INFO bit masks */
+#define OWN_MASK	(1<<31)	/* 0-CPU owns buffer, 1-EMAC owns buffer */
+#define FIRST_MASK	(1<<16)	/* First buffer in chain */
+#define LAST_MASK	(1<<17)	/* Last buffer in chain */
+#define LEN_MASK	0x000007FF	/* last 11 bits */
+#define CRLS		(1<<21)
+#define DEFR		(1<<22)
+#define DROP		(1<<23)
+#define RTRY		(1<<24)
+#define LTCL		(1<<28)
+#define UFLO		(1<<29)
+
+#define FOR_EMAC	OWN_MASK
+#define FOR_CPU		0
+
+/* ARC EMAC register set combines entries for MAC and MDIO */
+enum {
+	R_ID = 0,
+	R_STATUS,
+	R_ENABLE,
+	R_CTRL,
+	R_POLLRATE,
+	R_RXERR,
+	R_MISS,
+	R_TX_RING,
+	R_RX_RING,
+	R_ADDRL,
+	R_ADDRH,
+	R_LAFL,
+	R_LAFH,
+	R_MDIO,
+};
+
+#define TX_TIMEOUT		(400*HZ/1000)	/* Transmission timeout */
+
+#define ARC_EMAC_NAPI_WEIGHT	40		/* Workload for NAPI */
+
+#define EMAC_BUFFER_SIZE	1536		/* EMAC buffer size */
+
+/**
+ * struct arc_emac_bd - EMAC buffer descriptor (BD).
+ *
+ * @info:	Contains status information on the buffer itself.
+ * @data:	32-bit byte addressable pointer to the packet data.
+ */
+struct arc_emac_bd {
+	__le32 info;
+	dma_addr_t data;
+};
+
+/* Number of Rx/Tx BD's */
+#define RX_BD_NUM	128
+#define TX_BD_NUM	128
+
+#define RX_RING_SZ	(RX_BD_NUM * sizeof(struct arc_emac_bd))
+#define TX_RING_SZ	(TX_BD_NUM * sizeof(struct arc_emac_bd))
+
+/**
+ * struct buffer_state - Stores Rx/Tx buffer state.
+ * @sk_buff:	Pointer to socket buffer.
+ * @addr:	Start address of DMA-mapped memory region.
+ * @len:	Length of DMA-mapped memory region.
+ */
+struct buffer_state {
+	struct sk_buff *skb;
+	DEFINE_DMA_UNMAP_ADDR(addr);
+	DEFINE_DMA_UNMAP_LEN(len);
+};
+
+/**
+ * struct arc_emac_priv - Storage of EMAC's private information.
+ * @dev:	Pointer to the current device.
+ * @ndev:	Pointer to the current network device.
+ * @phy_dev:	Pointer to attached PHY device.
+ * @bus:	Pointer to the current MII bus.
+ * @regs:	Base address of EMAC memory-mapped control registers.
+ * @napi:	Structure for NAPI.
+ * @stats:	Network device statistics.
+ * @rxbd:	Pointer to Rx BD ring.
+ * @txbd:	Pointer to Tx BD ring.
+ * @rxbd_dma:	DMA handle for Rx BD ring.
+ * @txbd_dma:	DMA handle for Tx BD ring.
+ * @rx_buff:	Storage for Rx buffers states.
+ * @tx_buff:	Storage for Tx buffers states.
+ * @txbd_curr:	Index of Tx BD to use on the next "ndo_start_xmit".
+ * @txbd_dirty:	Index of Tx BD to free on the next Tx interrupt.
+ * @last_rx_bd:	Index of the last Rx BD we've got from EMAC.
+ * @link:	PHY's last seen link state.
+ * @duplex:	PHY's last set duplex mode.
+ * @speed:	PHY's last set speed.
+ * @max_speed:	Maximum supported by current system network data-rate.
+ */
+struct arc_emac_priv {
+	/* Devices */
+	struct device *dev;
+	struct net_device *ndev;
+	struct phy_device *phy_dev;
+	struct mii_bus *bus;
+
+	void __iomem *regs;
+
+	struct napi_struct napi;
+	struct net_device_stats stats;
+
+	struct arc_emac_bd *rxbd;
+	struct arc_emac_bd *txbd;
+
+	dma_addr_t rxbd_dma;
+	dma_addr_t txbd_dma;
+
+	struct buffer_state rx_buff[RX_BD_NUM];
+	struct buffer_state tx_buff[TX_BD_NUM];
+	unsigned int txbd_curr;
+	unsigned int txbd_dirty;
+
+	unsigned int last_rx_bd;
+
+	unsigned int link;
+	unsigned int duplex;
+	unsigned int speed;
+	unsigned int max_speed;
+};
+
+/**
+ * arc_reg_set - Sets EMAC register with provided value.
+ * @priv:	Pointer to ARC EMAC private data structure.
+ * @reg:	Register offset from base address.
+ * @value:	Value to set in register.
+ */
+static inline void arc_reg_set(struct arc_emac_priv *priv, int reg, int value)
+{
+	iowrite32(value, priv->regs + reg * sizeof(int));
+}
+
+/**
+ * arc_reg_get - Gets value of specified EMAC register.
+ * @priv:	Pointer to ARC EMAC private data structure.
+ * @reg:	Register offset from base address.
+ *
+ * returns:	Value of requested register.
+ */
+static inline unsigned int arc_reg_get(struct arc_emac_priv *priv, int reg)
+{
+	return ioread32(priv->regs + reg * sizeof(int));
+}
+
+/**
+ * arc_reg_or - Applies mask to specified EMAC register - ("reg" | "mask").
+ * @priv:	Pointer to ARC EMAC private data structure.
+ * @reg:	Register offset from base address.
+ * @mask:	Mask to apply to specified register.
+ *
+ * This function reads initial register value, then applies provided mask
+ * to it and then writes register back.
+ */
+static inline void arc_reg_or(struct arc_emac_priv *priv, int reg, int mask)
+{
+	unsigned int value = arc_reg_get(priv, reg);
+	arc_reg_set(priv, reg, value | mask);
+}
+
+/**
+ * arc_reg_clr - Applies mask to specified EMAC register - ("reg" & ~"mask").
+ * @priv:	Pointer to ARC EMAC private data structure.
+ * @reg:	Register offset from base address.
+ * @mask:	Mask to apply to specified register.
+ *
+ * This function reads initial register value, then applies provided mask
+ * to it and then writes register back.
+ */
+static inline void arc_reg_clr(struct arc_emac_priv *priv, int reg, int mask)
+{
+	unsigned int value = arc_reg_get(priv, reg);
+	arc_reg_set(priv, reg, value & ~mask);
+}
+
+int arc_mdio_probe(struct platform_device *pdev, struct arc_emac_priv *priv);
+int arc_mdio_remove(struct arc_emac_priv *priv);
+
+#endif /* ARC_EMAC_H */

drivers/net/ethernet/arc/emac_mdio.c

+/*
+ * 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;
+}