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authorAlexey Brodkin <Alexey.Brodkin@synopsys.com>2013-06-24 09:54:27 +0400
committerDavid S. Miller <davem@davemloft.net>2013-06-25 16:34:32 -0700
commite4f2379db6c6823c5d4a4c2c912df00c65de51d7 (patch)
treed02226bf72c9320c01df59ee9ad77de37d41acc5
parent62208f12451f723cd9e9f1d6d22866a61545e488 (diff)
downloadlinux-e4f2379db6c6823c5d4a4c2c912df00c65de51d7.tar.bz2
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>
-rw-r--r--Documentation/devicetree/bindings/net/arc_emac.txt38
-rw-r--r--drivers/net/ethernet/Kconfig1
-rw-r--r--drivers/net/ethernet/Makefile1
-rw-r--r--drivers/net/ethernet/arc/Kconfig31
-rw-r--r--drivers/net/ethernet/arc/Makefile6
-rw-r--r--drivers/net/ethernet/arc/emac.h214
-rw-r--r--drivers/net/ethernet/arc/emac_main.c806
-rw-r--r--drivers/net/ethernet/arc/emac_mdio.c152
8 files changed, 1249 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/net/arc_emac.txt b/Documentation/devicetree/bindings/net/arc_emac.txt
new file mode 100644
index 000000000000..bcbc3f009158
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/arc_emac.txt
@@ -0,0 +1,38 @@
+* 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>;
+ };
+ };
diff --git a/drivers/net/ethernet/Kconfig b/drivers/net/ethernet/Kconfig
index a989669b353a..2037080c504d 100644
--- a/drivers/net/ethernet/Kconfig
+++ b/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"
diff --git a/drivers/net/ethernet/Makefile b/drivers/net/ethernet/Makefile
index 009da27b6e26..390bd0bfaa27 100644
--- a/drivers/net/ethernet/Makefile
+++ b/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/
diff --git a/drivers/net/ethernet/arc/Kconfig b/drivers/net/ethernet/arc/Kconfig
new file mode 100644
index 000000000000..514c57fd26f1
--- /dev/null
+++ b/drivers/net/ethernet/arc/Kconfig
@@ -0,0 +1,31 @@
+#
+# 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
diff --git a/drivers/net/ethernet/arc/Makefile b/drivers/net/ethernet/arc/Makefile
new file mode 100644
index 000000000000..00c8657637d5
--- /dev/null
+++ b/drivers/net/ethernet/arc/Makefile
@@ -0,0 +1,6 @@
+#
+# Makefile for the ARC network device drivers.
+#
+
+arc_emac-objs := emac_main.o emac_mdio.o
+obj-$(CONFIG_ARC_EMAC) += arc_emac.o
diff --git a/drivers/net/ethernet/arc/emac.h b/drivers/net/ethernet/arc/emac.h
new file mode 100644
index 000000000000..dc08678bf9a4
--- /dev/null
+++ b/drivers/net/ethernet/arc/emac.h
@@ -0,0 +1,214 @@
+/*
+ * 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 */
diff --git a/drivers/net/ethernet/arc/emac_main.c b/drivers/net/ethernet/arc/emac_main.c
new file mode 100644
index 000000000000..20345f6bf894
--- /dev/null
+++ b/drivers/net/ethernet/arc/emac_main.c
@@ -0,0 +1,806 @@
+/*
+ * Copyright (C) 2004-2013 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Driver for the ARC EMAC 10100 (hardware revision 5)
+ *
+ * Contributors:
+ * Amit Bhor
+ * Sameer Dhavale
+ * Vineet Gupta
+ */
+
+#include <linux/etherdevice.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_mdio.h>
+#include <linux/of_net.h>
+#include <linux/of_platform.h>
+
+#include "emac.h"
+
+#define DRV_NAME "arc_emac"
+#define DRV_VERSION "1.0"
+
+/**
+ * arc_emac_adjust_link - Adjust the PHY link duplex.
+ * @ndev: Pointer to the net_device structure.
+ *
+ * This function is called to change the duplex setting after auto negotiation
+ * is done by the PHY.
+ */
+static void arc_emac_adjust_link(struct net_device *ndev)
+{
+ struct arc_emac_priv *priv = netdev_priv(ndev);
+ struct phy_device *phy_dev = priv->phy_dev;
+ unsigned int reg, state_changed = 0;
+
+ if (priv->link != phy_dev->link) {
+ priv->link = phy_dev->link;
+ state_changed = 1;
+ }
+
+ if (priv->speed != phy_dev->speed) {
+ priv->speed = phy_dev->speed;
+ state_changed = 1;
+ }
+
+ if (priv->duplex != phy_dev->duplex) {
+ reg = arc_reg_get(priv, R_CTRL);
+
+ if (DUPLEX_FULL == phy_dev->duplex)
+ reg |= ENFL_MASK;
+ else
+ reg &= ~ENFL_MASK;
+
+ arc_reg_set(priv, R_CTRL, reg);
+ priv->duplex = phy_dev->duplex;
+ state_changed = 1;
+ }
+
+ if (state_changed)
+ phy_print_status(phy_dev);
+}
+
+/**
+ * arc_emac_get_settings - Get PHY settings.
+ * @ndev: Pointer to net_device structure.
+ * @cmd: Pointer to ethtool_cmd structure.
+ *
+ * This implements ethtool command for getting PHY settings. If PHY could
+ * not be found, the function returns -ENODEV. This function calls the
+ * relevant PHY ethtool API to get the PHY settings.
+ * Issue "ethtool ethX" under linux prompt to execute this function.
+ */
+static int arc_emac_get_settings(struct net_device *ndev,
+ struct ethtool_cmd *cmd)
+{
+ struct arc_emac_priv *priv = netdev_priv(ndev);
+
+ return phy_ethtool_gset(priv->phy_dev, cmd);
+}
+
+/**
+ * arc_emac_set_settings - Set PHY settings as passed in the argument.
+ * @ndev: Pointer to net_device structure.
+ * @cmd: Pointer to ethtool_cmd structure.
+ *
+ * This implements ethtool command for setting various PHY settings. If PHY
+ * could not be found, the function returns -ENODEV. This function calls the
+ * relevant PHY ethtool API to set the PHY.
+ * Issue e.g. "ethtool -s ethX speed 1000" under linux prompt to execute this
+ * function.
+ */
+static int arc_emac_set_settings(struct net_device *ndev,
+ struct ethtool_cmd *cmd)
+{
+ struct arc_emac_priv *priv = netdev_priv(ndev);
+
+ if (!capable(CAP_NET_ADMIN))
+ return -EPERM;
+
+ return phy_ethtool_sset(priv->phy_dev, cmd);
+}
+
+/**
+ * arc_emac_get_drvinfo - Get EMAC driver information.
+ * @ndev: Pointer to net_device structure.
+ * @info: Pointer to ethtool_drvinfo structure.
+ *
+ * This implements ethtool command for getting the driver information.
+ * Issue "ethtool -i ethX" under linux prompt to execute this function.
+ */
+static void arc_emac_get_drvinfo(struct net_device *ndev,
+ struct ethtool_drvinfo *info)
+{
+ strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
+ strlcpy(info->version, DRV_VERSION, sizeof(info->version));
+}
+
+static const struct ethtool_ops arc_emac_ethtool_ops = {
+ .get_settings = arc_emac_get_settings,
+ .set_settings = arc_emac_set_settings,
+ .get_drvinfo = arc_emac_get_drvinfo,
+ .get_link = ethtool_op_get_link,
+};
+
+#define FIRST_OR_LAST_MASK (FIRST_MASK | LAST_MASK)
+
+/**
+ * arc_emac_tx_clean - clears processed by EMAC Tx BDs.
+ * @ndev: Pointer to the network device.
+ */
+static void arc_emac_tx_clean(struct net_device *ndev)
+{
+ struct arc_emac_priv *priv = netdev_priv(ndev);
+ struct net_device_stats *stats = &priv->stats;
+ unsigned int i;
+
+ for (i = 0; i < TX_BD_NUM; i++) {
+ unsigned int *txbd_dirty = &priv->txbd_dirty;
+ struct arc_emac_bd *txbd = &priv->txbd[*txbd_dirty];
+ struct buffer_state *tx_buff = &priv->tx_buff[*txbd_dirty];
+ struct sk_buff *skb = tx_buff->skb;
+ unsigned int info = le32_to_cpu(txbd->info);
+
+ *txbd_dirty = (*txbd_dirty + 1) % TX_BD_NUM;
+
+ if ((info & FOR_EMAC) || !txbd->data)
+ break;
+
+ if (unlikely(info & (DROP | DEFR | LTCL | UFLO))) {
+ stats->tx_errors++;
+ stats->tx_dropped++;
+
+ if (info & DEFR)
+ stats->tx_carrier_errors++;
+
+ if (info & LTCL)
+ stats->collisions++;
+
+ if (info & UFLO)
+ stats->tx_fifo_errors++;
+ } else if (likely(info & FIRST_OR_LAST_MASK)) {
+ stats->tx_packets++;
+ stats->tx_bytes += skb->len;
+ }
+
+ dma_unmap_single(&ndev->dev, dma_unmap_addr(&tx_buff, addr),
+ dma_unmap_len(&tx_buff, len), DMA_TO_DEVICE);
+
+ /* return the sk_buff to system */
+ dev_kfree_skb_irq(skb);
+
+ txbd->data = 0;
+ txbd->info = 0;
+
+ if (netif_queue_stopped(ndev))
+ netif_wake_queue(ndev);
+ }
+}
+
+/**
+ * arc_emac_rx - processing of Rx packets.
+ * @ndev: Pointer to the network device.
+ * @budget: How many BDs to process on 1 call.
+ *
+ * returns: Number of processed BDs
+ *
+ * Iterate through Rx BDs and deliver received packages to upper layer.
+ */
+static int arc_emac_rx(struct net_device *ndev, int budget)
+{
+ struct arc_emac_priv *priv = netdev_priv(ndev);
+ unsigned int work_done;
+
+ for (work_done = 0; work_done <= budget; work_done++) {
+ unsigned int *last_rx_bd = &priv->last_rx_bd;
+ struct net_device_stats *stats = &priv->stats;
+ struct buffer_state *rx_buff = &priv->rx_buff[*last_rx_bd];
+ struct arc_emac_bd *rxbd = &priv->rxbd[*last_rx_bd];
+ unsigned int buflen = EMAC_BUFFER_SIZE;
+ unsigned int pktlen, info = le32_to_cpu(rxbd->info);
+ struct sk_buff *skb;
+ dma_addr_t addr;
+
+ if (unlikely((info & OWN_MASK) == FOR_EMAC))
+ break;
+
+ /* Make a note that we saw a packet at this BD.
+ * So next time, driver starts from this + 1
+ */
+ *last_rx_bd = (*last_rx_bd + 1) % RX_BD_NUM;
+
+ if (unlikely((info & FIRST_OR_LAST_MASK) !=
+ FIRST_OR_LAST_MASK)) {
+ /* We pre-allocate buffers of MTU size so incoming
+ * packets won't be split/chained.
+ */
+ if (net_ratelimit())
+ netdev_err(ndev, "incomplete packet received\n");
+
+ /* Return ownership to EMAC */
+ rxbd->info = cpu_to_le32(FOR_EMAC | buflen);
+ stats->rx_errors++;
+ stats->rx_length_errors++;
+ continue;
+ }
+
+ pktlen = info & LEN_MASK;
+ stats->rx_packets++;
+ stats->rx_bytes += pktlen;
+ skb = rx_buff->skb;
+ skb_put(skb, pktlen);
+ skb->dev = ndev;
+ skb->protocol = eth_type_trans(skb, ndev);
+
+ dma_unmap_single(&ndev->dev, dma_unmap_addr(&rx_buff, addr),
+ dma_unmap_len(&rx_buff, len), DMA_FROM_DEVICE);
+
+ /* Prepare the BD for next cycle */
+ rx_buff->skb = netdev_alloc_skb_ip_align(ndev, buflen);
+ if (unlikely(!rx_buff->skb)) {
+ stats->rx_errors++;
+ /* Because receive_skb is below, increment rx_dropped */
+ stats->rx_dropped++;
+ continue;
+ }
+
+ /* receive_skb only if new skb was allocated to avoid holes */
+ netif_receive_skb(skb);
+
+ addr = dma_map_single(&ndev->dev, (void *)rx_buff->skb->data,
+ buflen, DMA_FROM_DEVICE);
+ if (dma_mapping_error(&ndev->dev, addr)) {
+ if (net_ratelimit())
+ netdev_err(ndev, "cannot dma map\n");
+ dev_kfree_skb(rx_buff->skb);
+ stats->rx_errors++;
+ continue;
+ }
+ dma_unmap_addr_set(&rx_buff, mapping, addr);
+ dma_unmap_len_set(&rx_buff, len, buflen);
+
+ rxbd->data = cpu_to_le32(rx_buff->skb->data);
+
+ /* Make sure pointer to data buffer is set */
+ wmb();
+
+ /* Return ownership to EMAC */
+ rxbd->info = cpu_to_le32(FOR_EMAC | buflen);
+ }
+
+ return work_done;
+}
+
+/**
+ * arc_emac_poll - NAPI poll handler.
+ * @napi: Pointer to napi_struct structure.
+ * @budget: How many BDs to process on 1 call.
+ *
+ * returns: Number of processed BDs
+ */
+static int arc_emac_poll(struct napi_struct *napi, int budget)
+{
+ struct net_device *ndev = napi->dev;
+ struct arc_emac_priv *priv = netdev_priv(ndev);
+ unsigned int work_done;
+
+ arc_emac_tx_clean(ndev);
+
+ work_done = arc_emac_rx(ndev, budget);
+ if (work_done < budget) {
+ napi_complete(napi);
+ arc_reg_or(priv, R_ENABLE, RXINT_MASK);
+ }
+
+ return work_done;
+}
+
+/**
+ * arc_emac_intr - Global interrupt handler for EMAC.
+ * @irq: irq number.
+ * @dev_instance: device instance.
+ *
+ * returns: IRQ_HANDLED for all cases.
+ *
+ * ARC EMAC has only 1 interrupt line, and depending on bits raised in
+ * STATUS register we may tell what is a reason for interrupt to fire.
+ */
+static irqreturn_t arc_emac_intr(int irq, void *dev_instance)
+{
+ struct net_device *ndev = dev_instance;
+ struct arc_emac_priv *priv = netdev_priv(ndev);
+ struct net_device_stats *stats = &priv->stats;
+ unsigned int status;
+
+ status = arc_reg_get(priv, R_STATUS);
+ status &= ~MDIO_MASK;
+
+ /* Reset all flags except "MDIO complete" */
+ arc_reg_set(priv, R_STATUS, status);
+
+ if (status & RXINT_MASK) {
+ if (likely(napi_schedule_prep(&priv->napi))) {
+ arc_reg_clr(priv, R_ENABLE, RXINT_MASK);
+ __napi_schedule(&priv->napi);
+ }
+ }
+
+ if (status & ERR_MASK) {
+ /* MSER/RXCR/RXFR/RXFL interrupt fires on corresponding
+ * 8-bit error counter overrun.
+ */
+
+ if (status & MSER_MASK) {
+ stats->rx_missed_errors += 0x100;
+ stats->rx_errors += 0x100;
+ }
+
+ if (status & RXCR_MASK) {
+ stats->rx_crc_errors += 0x100;
+ stats->rx_errors += 0x100;
+ }
+
+ if (status & RXFR_MASK) {
+ stats->rx_frame_errors += 0x100;
+ stats->rx_errors += 0x100;
+ }
+
+ if (status & RXFL_MASK) {
+ stats->rx_over_errors += 0x100;
+ stats->rx_errors += 0x100;
+ }
+ }
+
+ return IRQ_HANDLED;
+}
+
+/**
+ * arc_emac_open - Open the network device.
+ * @ndev: Pointer to the network device.
+ *
+ * returns: 0, on success or non-zero error value on failure.
+ *
+ * This function sets the MAC address, requests and enables an IRQ
+ * for the EMAC device and starts the Tx queue.
+ * It also connects to the phy device.
+ */
+static int arc_emac_open(struct net_device *ndev)
+{
+ struct arc_emac_priv *priv = netdev_priv(ndev);
+ struct phy_device *phy_dev = priv->phy_dev;
+ struct arc_emac_bd *bd;
+ struct sk_buff *skb;
+ int i;
+
+ phy_dev->autoneg = AUTONEG_ENABLE;
+ phy_dev->speed = 0;
+ phy_dev->duplex = 0;
+ phy_dev->advertising = phy_dev->supported;
+
+ if (priv->max_speed > 100) {
+ phy_dev->advertising &= PHY_GBIT_FEATURES;
+ } else if (priv->max_speed <= 100) {
+ phy_dev->advertising &= PHY_BASIC_FEATURES;
+ if (priv->max_speed <= 10) {
+ phy_dev->advertising &= ~SUPPORTED_100baseT_Half;
+ phy_dev->advertising &= ~SUPPORTED_100baseT_Full;
+ }
+ }
+
+ /* Allocate and set buffers for Rx BD's */
+ bd = priv->rxbd;
+ for (i = 0; i < RX_BD_NUM; i++) {
+ skb = netdev_alloc_skb_ip_align(ndev, EMAC_BUFFER_SIZE);
+ if (unlikely(!skb))
+ return -ENOMEM;
+
+ priv->rx_buff[i].skb = skb;
+ bd->data = cpu_to_le32(skb->data);
+
+ /* Make sure pointer to data buffer is set */
+ wmb();
+
+ /* Set ownership to EMAC */
+ bd->info = cpu_to_le32(FOR_EMAC | EMAC_BUFFER_SIZE);
+ bd++;
+ }
+
+ priv->last_rx_bd = 0;
+
+ /* Clean Tx BD's */
+ memset(priv->txbd, 0, TX_RING_SZ);
+
+ /* Initialize logical address filter */
+ arc_reg_set(priv, R_LAFL, 0);
+ arc_reg_set(priv, R_LAFH, 0);
+
+ /* Set BD ring pointers for device side */
+ arc_reg_set(priv, R_RX_RING, (unsigned int)priv->rxbd_dma);
+ arc_reg_set(priv, R_TX_RING, (unsigned int)priv->txbd_dma);
+
+ /* Enable interrupts */
+ arc_reg_set(priv, R_ENABLE, RXINT_MASK | ERR_MASK);
+
+ /* Set CONTROL */
+ arc_reg_set(priv, R_CTRL,
+ (RX_BD_NUM << 24) | /* RX BD table length */
+ (TX_BD_NUM << 16) | /* TX BD table length */
+ TXRN_MASK | RXRN_MASK);
+
+ napi_enable(&priv->napi);
+
+ /* Enable EMAC */
+ arc_reg_or(priv, R_CTRL, EN_MASK);
+
+ phy_start_aneg(priv->phy_dev);
+
+ netif_start_queue(ndev);
+
+ return 0;
+}
+
+/**
+ * arc_emac_stop - Close the network device.
+ * @ndev: Pointer to the network device.
+ *
+ * This function stops the Tx queue, disables interrupts and frees the IRQ for
+ * the EMAC device.
+ * It also disconnects the PHY device associated with the EMAC device.
+ */
+static int arc_emac_stop(struct net_device *ndev)
+{
+ struct arc_emac_priv *priv = netdev_priv(ndev);
+
+ napi_disable(&priv->napi);
+ netif_stop_queue(ndev);
+
+ /* Disable interrupts */
+ arc_reg_clr(priv, R_ENABLE, RXINT_MASK | ERR_MASK);
+
+ /* Disable EMAC */
+ arc_reg_clr(priv, R_CTRL, EN_MASK);
+
+ return 0;
+}
+
+/**
+ * arc_emac_stats - Get system network statistics.
+ * @ndev: Pointer to net_device structure.
+ *
+ * Returns the address of the device statistics structure.
+ * Statistics are updated in interrupt handler.
+ */
+static struct net_device_stats *arc_emac_stats(struct net_device *ndev)
+{
+ struct arc_emac_priv *priv = netdev_priv(ndev);
+ struct net_device_stats *stats = &priv->stats;
+ unsigned long miss, rxerr;
+ u8 rxcrc, rxfram, rxoflow;
+
+ rxerr = arc_reg_get(priv, R_RXERR);
+ miss = arc_reg_get(priv, R_MISS);
+
+ rxcrc = rxerr;
+ rxfram = rxerr >> 8;
+ rxoflow = rxerr >> 16;
+
+ stats->rx_errors += miss;
+ stats->rx_errors += rxcrc + rxfram + rxoflow;
+
+ stats->rx_over_errors += rxoflow;
+ stats->rx_frame_errors += rxfram;
+ stats->rx_crc_errors += rxcrc;
+ stats->rx_missed_errors += miss;
+
+ return stats;
+}
+
+/**
+ * arc_emac_tx - Starts the data transmission.
+ * @skb: sk_buff pointer that contains data to be Transmitted.
+ * @ndev: Pointer to net_device structure.
+ *
+ * returns: NETDEV_TX_OK, on success
+ * NETDEV_TX_BUSY, if any of the descriptors are not free.
+ *
+ * This function is invoked from upper layers to initiate transmission.
+ */
+static int arc_emac_tx(struct sk_buff *skb, struct net_device *ndev)
+{
+ struct arc_emac_priv *priv = netdev_priv(ndev);
+ unsigned int len, *txbd_curr = &priv->txbd_curr;
+ struct net_device_stats *stats = &priv->stats;
+ __le32 *info = &priv->txbd[*txbd_curr].info;
+ dma_addr_t addr;
+
+ if (skb_padto(skb, ETH_ZLEN))
+ return NETDEV_TX_OK;
+
+ len = max_t(unsigned int, ETH_ZLEN, skb->len);
+
+ /* EMAC still holds this buffer in its possession.
+ * CPU must not modify this buffer descriptor
+ */
+ if (unlikely((le32_to_cpu(*info) & OWN_MASK) == FOR_EMAC)) {
+ netif_stop_queue(ndev);
+ return NETDEV_TX_BUSY;
+ }
+
+ addr = dma_map_single(&ndev->dev, (void *)skb->data, len,
+ DMA_TO_DEVICE);
+
+ if (unlikely(dma_mapping_error(&ndev->dev, addr))) {
+ stats->tx_dropped++;
+ stats->tx_errors++;
+ dev_kfree_skb(skb);
+ return NETDEV_TX_OK;
+ }
+ dma_unmap_addr_set(&priv->tx_buff[*txbd_curr], mapping, addr);
+ dma_unmap_len_set(&priv->tx_buff[*txbd_curr], len, len);
+
+ priv->tx_buff[*txbd_curr].skb = skb;
+ priv->txbd[*txbd_curr].data = cpu_to_le32(skb->data);
+
+ /* Make sure pointer to data buffer is set */
+ wmb();
+
+ *info = cpu_to_le32(FOR_EMAC | FIRST_OR_LAST_MASK | len);
+
+ /* Increment index to point to the next BD */
+ *txbd_curr = (*txbd_curr + 1) % TX_BD_NUM;
+
+ /* Get "info" of the next BD */
+ info = &priv->txbd[*txbd_curr].info;
+
+ /* Check if if Tx BD ring is full - next BD is still owned by EMAC */
+ if (unlikely((le32_to_cpu(*info) & OWN_MASK) == FOR_EMAC))
+ netif_stop_queue(ndev);
+
+ arc_reg_set(priv, R_STATUS, TXPL_MASK);
+
+ skb_tx_timestamp(skb);
+
+ return NETDEV_TX_OK;
+}
+
+/**
+ * arc_emac_set_address - Set the MAC address for this device.
+ * @ndev: Pointer to net_device structure.
+ * @p: 6 byte Address to be written as MAC address.
+ *
+ * This function copies the HW address from the sockaddr structure to the
+ * net_device structure and updates the address in HW.
+ *
+ * returns: -EBUSY if the net device is busy or 0 if the address is set
+ * successfully.
+ */
+static int arc_emac_set_address(struct net_device *ndev, void *p)
+{
+ struct arc_emac_priv *priv = netdev_priv(ndev);
+ struct sockaddr *addr = p;
+ unsigned int addr_low, addr_hi;
+
+ if (netif_running(ndev))
+ return -EBUSY;
+
+ if (!is_valid_ether_addr(addr->sa_data))
+ return -EADDRNOTAVAIL;
+
+ memcpy(ndev->dev_addr, addr->sa_data, ndev->addr_len);
+
+ addr_low = le32_to_cpu(*(__le32 *) &ndev->dev_addr[0]);
+ addr_hi = le16_to_cpu(*(__le16 *) &ndev->dev_addr[4]);
+
+ arc_reg_set(priv, R_ADDRL, addr_low);
+ arc_reg_set(priv, R_ADDRH, addr_hi);
+
+ return 0;
+}
+
+static const struct net_device_ops arc_emac_netdev_ops = {
+ .ndo_open = arc_emac_open,
+ .ndo_stop = arc_emac_stop,
+ .ndo_start_xmit = arc_emac_tx,
+ .ndo_set_mac_address = arc_emac_set_address,
+ .ndo_get_stats = arc_emac_stats,
+};
+
+static int arc_emac_probe(struct platform_device *pdev)
+{
+ struct resource res_regs, res_irq;
+ struct device_node *phy_node;
+ struct arc_emac_priv *priv;
+ struct net_device *ndev;
+ const char *mac_addr;
+ unsigned int id, clock_frequency;
+ int err;
+
+ if (!pdev->dev.of_node)
+ return -ENODEV;
+
+ /* Get PHY from device tree */
+ phy_node = of_parse_phandle(pdev->dev.of_node, "phy", 0);
+ if (!phy_node) {
+ dev_err(&pdev->dev, "failed to retrieve phy description from device tree\n");
+ return -ENODEV;
+ }
+
+ /* Get EMAC registers base address from device tree */
+ err = of_address_to_resource(pdev->dev.of_node, 0, &res_regs);
+ if (err) {
+ dev_err(&pdev->dev, "failed to retrieve registers base from device tree\n");
+ return -ENODEV;
+ }
+
+ /* Get CPU clock frequency from device tree */
+ if (of_property_read_u32(pdev->dev.of_node, "clock-frequency",
+ &clock_frequency)) {
+ dev_err(&pdev->dev, "failed to retrieve <clock-frequency> from device tree\n");
+ return -EINVAL;
+ }
+
+ /* Get IRQ from device tree */
+ err = of_irq_to_resource(pdev->dev.of_node, 0, &res_irq);
+ if (!err) {
+ dev_err(&pdev->dev, "failed to retrieve <irq> value from device tree\n");
+ return -ENODEV;
+ }
+
+ ndev = alloc_etherdev(sizeof(struct arc_emac_priv));
+ if (!ndev)
+ return -ENOMEM;
+
+ SET_NETDEV_DEV(ndev, &pdev->dev);
+
+ ndev->netdev_ops = &arc_emac_netdev_ops;
+ ndev->ethtool_ops = &arc_emac_ethtool_ops;
+ ndev->watchdog_timeo = TX_TIMEOUT;
+ /* FIXME :: no multicast support yet */
+ ndev->flags &= ~IFF_MULTICAST;
+
+ priv = netdev_priv(ndev);
+ priv->dev = &pdev->dev;
+ priv->ndev = ndev;
+
+ priv->regs = devm_ioremap_resource(&pdev->dev, &res_regs);
+ if (IS_ERR(priv->regs)) {
+ err = PTR_ERR(priv->regs);
+ goto out;
+ }
+ dev_dbg(&pdev->dev, "Registers base address is 0x%p\n", priv->regs);
+
+ id = arc_reg_get(priv, R_ID);
+
+ /* Check for EMAC revision 5 or 7, magic number */
+ if (!(id == 0x0005fd02 || id == 0x0007fd02)) {
+ dev_err(&pdev->dev, "ARC EMAC not detected, id=0x%x\n", id);
+ err = -ENODEV;
+ goto out;
+ }
+ dev_info(&pdev->dev, "ARC EMAC detected with id: 0x%x\n", id);
+
+ /* Set poll rate so that it polls every 1 ms */
+ arc_reg_set(priv, R_POLLRATE, clock_frequency / 1000000);
+
+ /* Get max speed of operation from device tree */
+ if (of_property_read_u32(pdev->dev.of_node, "max-speed",
+ &priv->max_speed)) {
+ dev_err(&pdev->dev, "failed to retrieve <max-speed> from device tree\n");
+ err = -EINVAL;
+ goto out;
+ }
+
+ ndev->irq = res_irq.start;
+ dev_info(&pdev->dev, "IRQ is %d\n", ndev->irq);
+
+ /* Register interrupt handler for device */
+ err = devm_request_irq(&pdev->dev, ndev->irq, arc_emac_intr, 0,
+ ndev->name, ndev);
+ if (err) {
+ dev_err(&pdev->dev, "could not allocate IRQ\n");
+ goto out;
+ }
+
+ /* Get MAC address from device tree */
+ mac_addr = of_get_mac_address(pdev->dev.of_node);
+
+ if (!mac_addr || !is_valid_ether_addr(mac_addr))
+ eth_hw_addr_random(ndev);
+ else
+ memcpy(ndev->dev_addr, mac_addr, ETH_ALEN);
+
+ dev_info(&pdev->dev, "MAC address is now %pM\n", ndev->dev_addr);
+
+ /* Do 1 allocation instead of 2 separate ones for Rx and Tx BD rings */
+ priv->rxbd = dmam_alloc_coherent(&pdev->dev, RX_RING_SZ + TX_RING_SZ,
+ &priv->rxbd_dma, GFP_KERNEL);
+
+ if (!priv->rxbd) {
+ dev_err(&pdev->dev, "failed to allocate data buffers\n");
+ err = -ENOMEM;
+ goto out;
+ }
+
+ priv->txbd = priv->rxbd + RX_BD_NUM;
+
+ priv->txbd_dma = priv->rxbd_dma + RX_RING_SZ;
+ dev_dbg(&pdev->dev, "EMAC Device addr: Rx Ring [0x%x], Tx Ring[%x]\n",
+ (unsigned int)priv->rxbd_dma, (unsigned int)priv->txbd_dma);
+
+ err = arc_mdio_probe(pdev, priv);
+ if (err) {
+ dev_err(&pdev->dev, "failed to probe MII bus\n");
+ goto out;
+ }
+
+ priv->phy_dev = of_phy_connect(ndev, phy_node, arc_emac_adjust_link, 0,
+ PHY_INTERFACE_MODE_MII);
+ if (!priv->phy_dev) {
+ dev_err(&pdev->dev, "of_phy_connect() failed\n");
+ err = -ENODEV;
+ goto out;
+ }
+
+ dev_info(&pdev->dev, "connected to %s phy with id 0x%x\n",
+ priv->phy_dev->drv->name, priv->phy_dev->phy_id);
+
+ netif_napi_add(ndev, &priv->napi, arc_emac_poll, ARC_EMAC_NAPI_WEIGHT);
+
+ err = register_netdev(ndev);
+ if (err) {
+ netif_napi_del(&priv->napi);
+ dev_err(&pdev->dev, "failed to register network device\n");
+ goto out;
+ }
+
+ return 0;
+
+out:
+ free_netdev(ndev);
+ return err;
+}
+
+static int arc_emac_remove(struct platform_device *pdev)
+{
+ struct net_device *ndev = platform_get_drvdata(pdev);
+ struct arc_emac_priv *priv = netdev_priv(ndev);
+
+ phy_disconnect(priv->phy_dev);
+ priv->phy_dev = NULL;
+ arc_mdio_remove(priv);
+ unregister_netdev(ndev);
+ netif_napi_del(&priv->napi);
+ free_netdev(ndev);
+
+ return 0;
+}
+
+static const struct of_device_id arc_emac_dt_ids[] = {
+ { .compatible = "snps,arc-emac" },
+ { /* Sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, arc_emac_dt_ids);
+
+static struct platform_driver arc_emac_driver = {
+ .probe = arc_emac_probe,
+ .remove = arc_emac_remove,
+ .driver = {
+ .name = DRV_NAME,
+ .owner = THIS_MODULE,
+ .of_match_table = arc_emac_dt_ids,
+ },
+};
+
+module_platform_driver(arc_emac_driver);
+
+MODULE_AUTHOR("Alexey Brodkin <abrodkin@synopsys.com>");
+MODULE_DESCRIPTION("ARC EMAC driver");
+MODULE_LICENSE("GPL");
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;
+}