 /***************************************************************************
 *
 * Copyright (C) 2007-2008 SMSC
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 *****************************************************************************/

#include <linux/module.h>
#include <linux/kmod.h>
#include <linux/init.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/ethtool.h>
#include <linux/mii.h>
#include <linux/usb.h>
#include <linux/crc32.h>
#include <linux/usb/usbnet.h>
#include "smsc95xx.h"

#define SMSC_CHIPNAME			"smsc95xx"
#define SMSC_DRIVER_VERSION		"1.0.4"
#define HS_USB_PKT_SIZE			(512)
#define FS_USB_PKT_SIZE			(64)
#define DEFAULT_HS_BURST_CAP_SIZE	(16 * 1024 + 5 * HS_USB_PKT_SIZE)
#define DEFAULT_FS_BURST_CAP_SIZE	(6 * 1024 + 33 * FS_USB_PKT_SIZE)
#define DEFAULT_BULK_IN_DELAY		(0x00002000)
#define MAX_SINGLE_PACKET_SIZE		(2048)
#define LAN95XX_EEPROM_MAGIC		(0x9500)
#define EEPROM_MAC_OFFSET		(0x01)
#define DEFAULT_TX_CSUM_ENABLE		(true)
#define DEFAULT_RX_CSUM_ENABLE		(true)
#define SMSC95XX_INTERNAL_PHY_ID	(1)
#define SMSC95XX_TX_OVERHEAD		(8)
#define SMSC95XX_TX_OVERHEAD_CSUM	(12)

struct smsc95xx_priv {
	u32 mac_cr;
	spinlock_t mac_cr_lock;
	bool use_tx_csum;
	bool use_rx_csum;
};

struct usb_context {
	struct usb_ctrlrequest req;
	struct usbnet *dev;
};

int turbo_mode = true;
module_param(turbo_mode, bool, 0644);
MODULE_PARM_DESC(turbo_mode, "Enable multiple frames per Rx transaction");

static int smsc95xx_read_reg(struct usbnet *dev, u32 index, u32 *data)
{
	u32 *buf = kmalloc(4, GFP_KERNEL);
	int ret;

	BUG_ON(!dev);

	if (!buf)
		return -ENOMEM;

	ret = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
		USB_VENDOR_REQUEST_READ_REGISTER,
		USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
		00, index, buf, 4, USB_CTRL_GET_TIMEOUT);

	if (unlikely(ret < 0))
		devwarn(dev, "Failed to read register index 0x%08x", index);

	le32_to_cpus(buf);
	*data = *buf;
	kfree(buf);

	return ret;
}

static int smsc95xx_write_reg(struct usbnet *dev, u32 index, u32 data)
{
	u32 *buf = kmalloc(4, GFP_KERNEL);
	int ret;

	BUG_ON(!dev);

	if (!buf)
		return -ENOMEM;

	*buf = data;
	cpu_to_le32s(buf);

	ret = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
		USB_VENDOR_REQUEST_WRITE_REGISTER,
		USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
		00, index, buf, 4, USB_CTRL_SET_TIMEOUT);

	if (unlikely(ret < 0))
		devwarn(dev, "Failed to write register index 0x%08x", index);

	kfree(buf);

	return ret;
}

/* Loop until the read is completed with timeout
 * called with phy_mutex held */
static int smsc95xx_phy_wait_not_busy(struct usbnet *dev)
{
	unsigned long start_time = jiffies;
	u32 val;

	do {
		smsc95xx_read_reg(dev, MII_ADDR, &val);
		if (!(val & MII_BUSY_))
			return 0;
	} while (!time_after(jiffies, start_time + HZ));

	return -EIO;
}

static int smsc95xx_mdio_read(struct net_device *netdev, int phy_id, int idx)
{
	struct usbnet *dev = netdev_priv(netdev);
	u32 val, addr;

	mutex_lock(&dev->phy_mutex);

	/* confirm MII not busy */
	if (smsc95xx_phy_wait_not_busy(dev)) {
		devwarn(dev, "MII is busy in smsc95xx_mdio_read");
		mutex_unlock(&dev->phy_mutex);
		return -EIO;
	}

	/* set the address, index & direction (read from PHY) */
	phy_id &= dev->mii.phy_id_mask;
	idx &= dev->mii.reg_num_mask;
	addr = (phy_id << 11) | (idx << 6) | MII_READ_;
	smsc95xx_write_reg(dev, MII_ADDR, addr);

	if (smsc95xx_phy_wait_not_busy(dev)) {
		devwarn(dev, "Timed out reading MII reg %02X", idx);
		mutex_unlock(&dev->phy_mutex);
		return -EIO;
	}

	smsc95xx_read_reg(dev, MII_DATA, &val);

	mutex_unlock(&dev->phy_mutex);

	return (u16)(val & 0xFFFF);
}

static void smsc95xx_mdio_write(struct net_device *netdev, int phy_id, int idx,
				int regval)
{
	struct usbnet *dev = netdev_priv(netdev);
	u32 val, addr;

	mutex_lock(&dev->phy_mutex);

	/* confirm MII not busy */
	if (smsc95xx_phy_wait_not_busy(dev)) {
		devwarn(dev, "MII is busy in smsc95xx_mdio_write");
		mutex_unlock(&dev->phy_mutex);
		return;
	}

	val = regval;
	smsc95xx_write_reg(dev, MII_DATA, val);

	/* set the address, index & direction (write to PHY) */
	phy_id &= dev->mii.phy_id_mask;
	idx &= dev->mii.reg_num_mask;
	addr = (phy_id << 11) | (idx << 6) | MII_WRITE_;
	smsc95xx_write_reg(dev, MII_ADDR, addr);

	if (smsc95xx_phy_wait_not_busy(dev))
		devwarn(dev, "Timed out writing MII reg %02X", idx);

	mutex_unlock(&dev->phy_mutex);
}

static int smsc95xx_wait_eeprom(struct usbnet *dev)
{
	unsigned long start_time = jiffies;
	u32 val;

	do {
		smsc95xx_read_reg(dev, E2P_CMD, &val);
		if (!(val & E2P_CMD_BUSY_) || (val & E2P_CMD_TIMEOUT_))
			break;
		udelay(40);
	} while (!time_after(jiffies, start_time + HZ));

	if (val & (E2P_CMD_TIMEOUT_ | E2P_CMD_BUSY_)) {
		devwarn(dev, "EEPROM read operation timeout");
		return -EIO;
	}

	return 0;
}

static int smsc95xx_eeprom_confirm_not_busy(struct usbnet *dev)
{
	unsigned long start_time = jiffies;
	u32 val;

	do {
		smsc95xx_read_reg(dev, E2P_CMD, &val);

		if (!(val & E2P_CMD_LOADED_)) {
			devwarn(dev, "No EEPROM present");
			return -EIO;
		}

		if (!(val & E2P_CMD_BUSY_))
			return 0;

		udelay(40);
	} while (!time_after(jiffies, start_time + HZ));

	devwarn(dev, "EEPROM is busy");
	return -EIO;
}

static int smsc95xx_read_eeprom(struct usbnet *dev, u32 offset, u32 length,
				u8 *data)
{
	u32 val;
	int i, ret;

	BUG_ON(!dev);
	BUG_ON(!data);

	ret = smsc95xx_eeprom_confirm_not_busy(dev);
	if (ret)
		return ret;

	for (i = 0; i < length; i++) {
		val = E2P_CMD_BUSY_ | E2P_CMD_READ_ | (offset & E2P_CMD_ADDR_);
		smsc95xx_write_reg(dev, E2P_CMD, val);

		ret = smsc95xx_wait_eeprom(dev);
		if (ret < 0)
			return ret;

		smsc95xx_read_reg(dev, E2P_DATA, &val);

		data[i] = val & 0xFF;
		offset++;
	}

	return 0;
}

static int smsc95xx_write_eeprom(struct usbnet *dev, u32 offset, u32 length,
				 u8 *data)
{
	u32 val;
	int i, ret;

	BUG_ON(!dev);
	BUG_ON(!data);

	ret = smsc95xx_eeprom_confirm_not_busy(dev);
	if (ret)
		return ret;

	/* Issue write/erase enable command */
	val = E2P_CMD_BUSY_ | E2P_CMD_EWEN_;
	smsc95xx_write_reg(dev, E2P_CMD, val);

	ret = smsc95xx_wait_eeprom(dev);
	if (ret < 0)
		return ret;

	for (i = 0; i < length; i++) {

		/* Fill data register */
		val = data[i];
		smsc95xx_write_reg(dev, E2P_DATA, val);

		/* Send "write" command */
		val = E2P_CMD_BUSY_ | E2P_CMD_WRITE_ | (offset & E2P_CMD_ADDR_);
		smsc95xx_write_reg(dev, E2P_CMD, val);

		ret = smsc95xx_wait_eeprom(dev);
		if (ret < 0)
			return ret;

		offset++;
	}

	return 0;
}

static void smsc95xx_async_cmd_callback(struct urb *urb)
{
	struct usb_context *usb_context = urb->context;
	struct usbnet *dev = usb_context->dev;
	int status = urb->status;

	if (status < 0)
		devwarn(dev, "async callback failed with %d", status);

	kfree(usb_context);
	usb_free_urb(urb);
}

static int smsc95xx_write_reg_async(struct usbnet *dev, u16 index, u32 *data)
{
	struct usb_context *usb_context;
	int status;
	struct urb *urb;
	const u16 size = 4;

	urb = usb_alloc_urb(0, GFP_ATOMIC);
	if (!urb) {
		devwarn(dev, "Error allocating URB");
		return -ENOMEM;
	}

	usb_context = kmalloc(sizeof(struct usb_context), GFP_ATOMIC);
	if (usb_context == NULL) {
		devwarn(dev, "Error allocating control msg");
		usb_free_urb(urb);
		return -ENOMEM;
	}

	usb_context->req.bRequestType =
		USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE;
	usb_context->req.bRequest = USB_VENDOR_REQUEST_WRITE_REGISTER;
	usb_context->req.wValue = 00;
	usb_context->req.wIndex = cpu_to_le16(index);
	usb_context->req.wLength = cpu_to_le16(size);

	usb_fill_control_urb(urb, dev->udev, usb_sndctrlpipe(dev->udev, 0),
		(void *)&usb_context->req, data, size,
		smsc95xx_async_cmd_callback,
		(void *)usb_context);

	status = usb_submit_urb(urb, GFP_ATOMIC);
	if (status < 0) {
		devwarn(dev, "Error submitting control msg, sts=%d", status);
		kfree(usb_context);
		usb_free_urb(urb);
	}

	return status;
}

/* returns hash bit number for given MAC address
 * example:
 * 01 00 5E 00 00 01 -> returns bit number 31 */
static unsigned int smsc95xx_hash(char addr[ETH_ALEN])
{
	return (ether_crc(ETH_ALEN, addr) >> 26) & 0x3f;
}

static void smsc95xx_set_multicast(struct net_device *netdev)
{
	struct usbnet *dev = netdev_priv(netdev);
	struct smsc95xx_priv *pdata = (struct smsc95xx_priv *)(dev->data[0]);
	u32 hash_hi = 0;
	u32 hash_lo = 0;
	unsigned long flags;

	spin_lock_irqsave(&pdata->mac_cr_lock, flags);

	if (dev->net->flags & IFF_PROMISC) {
		if (netif_msg_drv(dev))
			devdbg(dev, "promiscuous mode enabled");
		pdata->mac_cr |= MAC_CR_PRMS_;
		pdata->mac_cr &= ~(MAC_CR_MCPAS_ | MAC_CR_HPFILT_);
	} else if (dev->net->flags & IFF_ALLMULTI) {
		if (netif_msg_drv(dev))
			devdbg(dev, "receive all multicast enabled");
		pdata->mac_cr |= MAC_CR_MCPAS_;
		pdata->mac_cr &= ~(MAC_CR_PRMS_ | MAC_CR_HPFILT_);
	} else if (dev->net->mc_count > 0) {
		struct dev_mc_list *mc_list = dev->net->mc_list;
		int count = 0;

		pdata->mac_cr |= MAC_CR_HPFILT_;
		pdata->mac_cr &= ~(MAC_CR_PRMS_ | MAC_CR_MCPAS_);

		while (mc_list) {
			count++;
			if (mc_list->dmi_addrlen == ETH_ALEN) {
				u32 bitnum = smsc95xx_hash(mc_list->dmi_addr);
				u32 mask = 0x01 << (bitnum & 0x1F);
				if (bitnum & 0x20)
					hash_hi |= mask;
				else
					hash_lo |= mask;
			} else {
				devwarn(dev, "dmi_addrlen != 6");
			}
			mc_list = mc_list->next;
		}

		if (count != ((u32)dev->net->mc_count))
			devwarn(dev, "mc_count != dev->mc_count");

		if (netif_msg_drv(dev))
			devdbg(dev, "HASHH=0x%08X, HASHL=0x%08X", hash_hi,
				hash_lo);
	} else {
		if (netif_msg_drv(dev))
			devdbg(dev, "receive own packets only");
		pdata->mac_cr &=
			~(MAC_CR_PRMS_ | MAC_CR_MCPAS_ | MAC_CR_HPFILT_);
	}

	spin_unlock_irqrestore(&pdata->mac_cr_lock, flags);

	/* Initiate async writes, as we can't wait for completion here */
	smsc95xx_write_reg_async(dev, HASHH, &hash_hi);
	smsc95xx_write_reg_async(dev, HASHL, &hash_lo);
	smsc95xx_write_reg_async(dev, MAC_CR, &pdata->mac_cr);
}

static void smsc95xx_phy_update_flowcontrol(struct usbnet *dev, u8 duplex,
					    u16 lcladv, u16 rmtadv)
{
	u32 flow, afc_cfg = 0;

	int ret = smsc95xx_read_reg(dev, AFC_CFG, &afc_cfg);
	if (ret < 0) {
		devwarn(dev, "error reading AFC_CFG");
		return;
	}

	if (duplex == DUPLEX_FULL) {
		u8 cap = mii_resolve_flowctrl_fdx(lcladv, rmtadv);

		if (cap & FLOW_CTRL_RX)
			flow = 0xFFFF0002;
		else
			flow = 0;

		if (cap & FLOW_CTRL_TX)
			afc_cfg |= 0xF;
		else
			afc_cfg &= ~0xF;

		if (netif_msg_link(dev))
			devdbg(dev, "rx pause %s, tx pause %s",
				(cap & FLOW_CTRL_RX ? "enabled" : "disabled"),
				(cap & FLOW_CTRL_TX ? "enabled" : "disabled"));
	} else {
		if (netif_msg_link(dev))
			devdbg(dev, "half duplex");
		flow = 0;
		afc_cfg |= 0xF;
	}

	smsc95xx_write_reg(dev, FLOW, flow);
	smsc95xx_write_reg(dev,	AFC_CFG, afc_cfg);
}

static int smsc95xx_link_reset(struct usbnet *dev)
{
	struct smsc95xx_priv *pdata = (struct smsc95xx_priv *)(dev->data[0]);
	struct mii_if_info *mii = &dev->mii;
	struct ethtool_cmd ecmd;
	unsigned long flags;
	u16 lcladv, rmtadv;
	u32 intdata;

	/* clear interrupt status */
	smsc95xx_mdio_read(dev->net, mii->phy_id, PHY_INT_SRC);
	intdata = 0xFFFFFFFF;
	smsc95xx_write_reg(dev, INT_STS, intdata);

	mii_check_media(mii, 1, 1);
	mii_ethtool_gset(&dev->mii, &ecmd);
	lcladv = smsc95xx_mdio_read(dev->net, mii->phy_id, MII_ADVERTISE);
	rmtadv = smsc95xx_mdio_read(dev->net, mii->phy_id, MII_LPA);

	if (netif_msg_link(dev))
		devdbg(dev, "speed: %d duplex: %d lcladv: %04x rmtadv: %04x",
			ecmd.speed, ecmd.duplex, lcladv, rmtadv);

	spin_lock_irqsave(&pdata->mac_cr_lock, flags);
	if (ecmd.duplex != DUPLEX_FULL) {
		pdata->mac_cr &= ~MAC_CR_FDPX_;
		pdata->mac_cr |= MAC_CR_RCVOWN_;
	} else {
		pdata->mac_cr &= ~MAC_CR_RCVOWN_;
		pdata->mac_cr |= MAC_CR_FDPX_;
	}
	spin_unlock_irqrestore(&pdata->mac_cr_lock, flags);

	smsc95xx_write_reg(dev, MAC_CR, pdata->mac_cr);

	smsc95xx_phy_update_flowcontrol(dev, ecmd.duplex, lcladv, rmtadv);

	return 0;
}

static void smsc95xx_status(struct usbnet *dev, struct urb *urb)
{
	u32 intdata;

	if (urb->actual_length != 4) {
		devwarn(dev, "unexpected urb length %d", urb->actual_length);
		return;
	}

	memcpy(&intdata, urb->transfer_buffer, 4);
	le32_to_cpus(&intdata);

	if (netif_msg_link(dev))
		devdbg(dev, "intdata: 0x%08X", intdata);

	if (intdata & INT_ENP_PHY_INT_)
		usbnet_defer_kevent(dev, EVENT_LINK_RESET);
	else
		devwarn(dev, "unexpected interrupt, intdata=0x%08X", intdata);
}

/* Enable or disable Tx & Rx checksum offload engines */
static int smsc95xx_set_csums(struct usbnet *dev)
{
	struct smsc95xx_priv *pdata = (struct smsc95xx_priv *)(dev->data[0]);
	u32 read_buf;
	int ret = smsc95xx_read_reg(dev, COE_CR, &read_buf);
	if (ret < 0) {
		devwarn(dev, "Failed to read COE_CR: %d", ret);
		return ret;
	}

	if (pdata->use_tx_csum)
		read_buf |= Tx_COE_EN_;
	else
		read_buf &= ~Tx_COE_EN_;

	if (pdata->use_rx_csum)
		read_buf |= Rx_COE_EN_;
	else
		read_buf &= ~Rx_COE_EN_;

	ret = smsc95xx_write_reg(dev, COE_CR, read_buf);
	if (ret < 0) {
		devwarn(dev, "Failed to write COE_CR: %d", ret);
		return ret;
	}

	if (netif_msg_hw(dev))
		devdbg(dev, "COE_CR = 0x%08x", read_buf);
	return 0;
}

static int smsc95xx_ethtool_get_eeprom_len(struct net_device *net)
{
	return MAX_EEPROM_SIZE;
}

static int smsc95xx_ethtool_get_eeprom(struct net_device *netdev,
				       struct ethtool_eeprom *ee, u8 *data)
{
	struct usbnet *dev = netdev_priv(netdev);

	ee->magic = LAN95XX_EEPROM_MAGIC;

	return smsc95xx_read_eeprom(dev, ee->offset, ee->len, data);
}

static int smsc95xx_ethtool_set_eeprom(struct net_device *netdev,
				       struct ethtool_eeprom *ee, u8 *data)
{
	struct usbnet *dev = netdev_priv(netdev);

	if (ee->magic != LAN95XX_EEPROM_MAGIC) {
		devwarn(dev, "EEPROM: magic value mismatch, magic = 0x%x",
			ee->magic);
		return -EINVAL;
	}

	return smsc95xx_write_eeprom(dev, ee->offset, ee->len, data);
}

static u32 smsc95xx_ethtool_get_rx_csum(struct net_device *netdev)
{
	struct usbnet *dev = netdev_priv(netdev);
	struct smsc95xx_priv *pdata = (struct smsc95xx_priv *)(dev->data[0]);

	return pdata->use_rx_csum;
}

static int smsc95xx_ethtool_set_rx_csum(struct net_device *netdev, u32 val)
{
	struct usbnet *dev = netdev_priv(netdev);
	struct smsc95xx_priv *pdata = (struct smsc95xx_priv *)(dev->data[0]);

	pdata->use_rx_csum = !!val;

	return smsc95xx_set_csums(dev);
}

static u32 smsc95xx_ethtool_get_tx_csum(struct net_device *netdev)
{
	struct usbnet *dev = netdev_priv(netdev);
	struct smsc95xx_priv *pdata = (struct smsc95xx_priv *)(dev->data[0]);

	return pdata->use_tx_csum;
}

static int smsc95xx_ethtool_set_tx_csum(struct net_device *netdev, u32 val)
{
	struct usbnet *dev = netdev_priv(netdev);
	struct smsc95xx_priv *pdata = (struct smsc95xx_priv *)(dev->data[0]);

	pdata->use_tx_csum = !!val;

	ethtool_op_set_tx_hw_csum(netdev, pdata->use_tx_csum);
	return smsc95xx_set_csums(dev);
}

static struct ethtool_ops smsc95xx_ethtool_ops = {
	.get_link	= usbnet_get_link,
	.nway_reset	= usbnet_nway_reset,
	.get_drvinfo	= usbnet_get_drvinfo,
	.get_msglevel	= usbnet_get_msglevel,
	.set_msglevel	= usbnet_set_msglevel,
	.get_settings	= usbnet_get_settings,
	.set_settings	= usbnet_set_settings,
	.get_eeprom_len	= smsc95xx_ethtool_get_eeprom_len,
	.get_eeprom	= smsc95xx_ethtool_get_eeprom,
	.set_eeprom	= smsc95xx_ethtool_set_eeprom,
	.get_tx_csum	= smsc95xx_ethtool_get_tx_csum,
	.set_tx_csum	= smsc95xx_ethtool_set_tx_csum,
	.get_rx_csum	= smsc95xx_ethtool_get_rx_csum,
	.set_rx_csum	= smsc95xx_ethtool_set_rx_csum,
};

static int smsc95xx_ioctl(struct net_device *netdev, struct ifreq *rq, int cmd)
{
	struct usbnet *dev = netdev_priv(netdev);

	if (!netif_running(netdev))
		return -EINVAL;

	return generic_mii_ioctl(&dev->mii, if_mii(rq), cmd, NULL);
}

static void smsc95xx_init_mac_address(struct usbnet *dev)
{
	/* try reading mac address from EEPROM */
	if (smsc95xx_read_eeprom(dev, EEPROM_MAC_OFFSET, ETH_ALEN,
			dev->net->dev_addr) == 0) {
		if (is_valid_ether_addr(dev->net->dev_addr)) {
			/* eeprom values are valid so use them */
			if (netif_msg_ifup(dev))
				devdbg(dev, "MAC address read from EEPROM");
			return;
		}
	}

	/* no eeprom, or eeprom values are invalid. generate random MAC */
	random_ether_addr(dev->net->dev_addr);
	if (netif_msg_ifup(dev))
		devdbg(dev, "MAC address set to random_ether_addr");
}

static int smsc95xx_set_mac_address(struct usbnet *dev)
{
	u32 addr_lo = dev->net->dev_addr[0] | dev->net->dev_addr[1] << 8 |
		dev->net->dev_addr[2] << 16 | dev->net->dev_addr[3] << 24;
	u32 addr_hi = dev->net->dev_addr[4] | dev->net->dev_addr[5] << 8;
	int ret;

	ret = smsc95xx_write_reg(dev, ADDRL, addr_lo);
	if (ret < 0) {
		devwarn(dev, "Failed to write ADDRL: %d", ret);
		return ret;
	}

	ret = smsc95xx_write_reg(dev, ADDRH, addr_hi);
	if (ret < 0) {
		devwarn(dev, "Failed to write ADDRH: %d", ret);
		return ret;
	}

	return 0;
}

/* starts the TX path */
static void smsc95xx_start_tx_path(struct usbnet *dev)
{
	struct smsc95xx_priv *pdata = (struct smsc95xx_priv *)(dev->data[0]);
	unsigned long flags;
	u32 reg_val;

	/* Enable Tx at MAC */
	spin_lock_irqsave(&pdata->mac_cr_lock, flags);
	pdata->mac_cr |= MAC_CR_TXEN_;
	spin_unlock_irqrestore(&pdata->mac_cr_lock, flags);

	smsc95xx_write_reg(dev, MAC_CR, pdata->mac_cr);

	/* Enable Tx at SCSRs */
	reg_val = TX_CFG_ON_;
	smsc95xx_write_reg(dev, TX_CFG, reg_val);
}

/* Starts the Receive path */
static void smsc95xx_start_rx_path(struct usbnet *dev)
{
	struct smsc95xx_priv *pdata = (struct smsc95xx_priv *)(dev->data[0]);
	unsigned long flags;

	spin_lock_irqsave(&pdata->mac_cr_lock, flags);
	pdata->mac_cr |= MAC_CR_RXEN_;
	spin_unlock_irqrestore(&pdata->mac_cr_lock, flags);

	smsc95xx_write_reg(dev, MAC_CR, pdata->mac_cr);
}

static int smsc95xx_phy_initialize(struct usbnet *dev)
{
	/* Initialize MII structure */
	dev->mii.dev = dev->net;
	dev->mii.mdio_read = smsc95xx_mdio_read;
	dev->mii.mdio_write = smsc95xx_mdio_write;
	dev->mii.phy_id_mask = 0x1f;
	dev->mii.reg_num_mask = 0x1f;
	dev->mii.phy_id = SMSC95XX_INTERNAL_PHY_ID;

	smsc95xx_mdio_write(dev->net, dev->mii.phy_id, MII_BMCR, BMCR_RESET);
	smsc95xx_mdio_write(dev->net, dev->mii.phy_id, MII_ADVERTISE,
		ADVERTISE_ALL | ADVERTISE_CSMA | ADVERTISE_PAUSE_CAP |
		ADVERTISE_PAUSE_ASYM);

	/* read to clear */
	smsc95xx_mdio_read(dev->net, dev->mii.phy_id, PHY_INT_SRC);

	smsc95xx_mdio_write(dev->net, dev->mii.phy_id, PHY_INT_MASK,
		PHY_INT_MASK_DEFAULT_);
	mii_nway_restart(&dev->mii);

	if (netif_msg_ifup(dev))
		devdbg(dev, "phy initialised succesfully");
	return 0;
}

static int smsc95xx_reset(struct usbnet *dev)
{
	struct smsc95xx_priv *pdata = (struct smsc95xx_priv *)(dev->data[0]);
	struct net_device *netdev = dev->net;
	u32 read_buf, write_buf, burst_cap;
	int ret = 0, timeout;

	if (netif_msg_ifup(dev))
		devdbg(dev, "entering smsc95xx_reset");

	write_buf = HW_CFG_LRST_;
	ret = smsc95xx_write_reg(dev, HW_CFG, write_buf);
	if (ret < 0) {
		devwarn(dev, "Failed to write HW_CFG_LRST_ bit in HW_CFG "
			"register, ret = %d", ret);
		return ret;
	}

	timeout = 0;
	do {
		ret = smsc95xx_read_reg(dev, HW_CFG, &read_buf);
		if (ret < 0) {
			devwarn(dev, "Failed to read HW_CFG: %d", ret);
			return ret;
		}
		msleep(10);
		timeout++;
	} while ((read_buf & HW_CFG_LRST_) && (timeout < 100));

	if (timeout >= 100) {
		devwarn(dev, "timeout waiting for completion of Lite Reset");
		return ret;
	}

	write_buf = PM_CTL_PHY_RST_;
	ret = smsc95xx_write_reg(dev, PM_CTRL, write_buf);
	if (ret < 0) {
		devwarn(dev, "Failed to write PM_CTRL: %d", ret);
		return ret;
	}

	timeout = 0;
	do {
		ret = smsc95xx_read_reg(dev, PM_CTRL, &read_buf);
		if (ret < 0) {
			devwarn(dev, "Failed to read PM_CTRL: %d", ret);
			return ret;
		}
		msleep(10);
		timeout++;
	} while ((read_buf & PM_CTL_PHY_RST_) && (timeout < 100));

	if (timeout >= 100) {
		devwarn(dev, "timeout waiting for PHY Reset");
		return ret;
	}

	smsc95xx_init_mac_address(dev);

	ret = smsc95xx_set_mac_address(dev);
	if (ret < 0)
		return ret;

	if (netif_msg_ifup(dev))
		devdbg(dev, "MAC Address: %pM", dev->net->dev_addr);

	ret = smsc95xx_read_reg(dev, HW_CFG, &read_buf);
	if (ret < 0) {
		devwarn(dev, "Failed to read HW_CFG: %d", ret);
		return ret;
	}

	if (netif_msg_ifup(dev))
		devdbg(dev, "Read Value from HW_CFG : 0x%08x", read_buf);

	read_buf |= HW_CFG_BIR_;

	ret = smsc95xx_write_reg(dev, HW_CFG, read_buf);
	if (ret < 0) {
		devwarn(dev, "Failed to write HW_CFG_BIR_ bit in HW_CFG "
			"register, ret = %d", ret);
		return ret;
	}

	ret = smsc95xx_read_reg(dev, HW_CFG, &read_buf);
	if (ret < 0) {
		devwarn(dev, "Failed to read HW_CFG: %d", ret);
		return ret;
	}
	if (netif_msg_ifup(dev))
		devdbg(dev, "Read Value from HW_CFG after writing "
			"HW_CFG_BIR_: 0x%08x", read_buf);

	if (!turbo_mode) {
		burst_cap = 0;
		dev->rx_urb_size = MAX_SINGLE_PACKET_SIZE;
	} else if (dev->udev->speed == USB_SPEED_HIGH) {
		burst_cap = DEFAULT_HS_BURST_CAP_SIZE / HS_USB_PKT_SIZE;
		dev->rx_urb_size = DEFAULT_HS_BURST_CAP_SIZE;
	} else {
		burst_cap = DEFAULT_FS_BURST_CAP_SIZE / FS_USB_PKT_SIZE;
		dev->rx_urb_size = DEFAULT_FS_BURST_CAP_SIZE;
	}

	if (netif_msg_ifup(dev))
		devdbg(dev, "rx_urb_size=%ld", (ulong)dev->rx_urb_size);

	ret = smsc95xx_write_reg(dev, BURST_CAP, burst_cap);
	if (ret < 0) {
		devwarn(dev, "Failed to write BURST_CAP: %d", ret);
		return ret;
	}

	ret = smsc95xx_read_reg(dev, BURST_CAP, &read_buf);
	if (ret < 0) {
		devwarn(dev, "Failed to read BURST_CAP: %d", ret);
		return ret;
	}
	if (netif_msg_ifup(dev))
		devdbg(dev, "Read Value from BURST_CAP after writing: 0x%08x",
			read_buf);

	read_buf = DEFAULT_BULK_IN_DELAY;
	ret = smsc95xx_write_reg(dev, BULK_IN_DLY, read_buf);
	if (ret < 0) {
		devwarn(dev, "ret = %d", ret);
		return ret;
	}

	ret = smsc95xx_read_reg(dev, BULK_IN_DLY, &read_buf);
	if (ret < 0) {
		devwarn(dev, "Failed to read BULK_IN_DLY: %d", ret);
		return ret;
	}
	if (netif_msg_ifup(dev))
		devdbg(dev, "Read Value from BULK_IN_DLY after writing: "
			"0x%08x", read_buf);

	ret = smsc95xx_read_reg(dev, HW_CFG, &read_buf);
	if (ret < 0) {
		devwarn(dev, "Failed to read HW_CFG: %d", ret);
		return ret;
	}
	if (netif_msg_ifup(dev))
		devdbg(dev, "Read Value from HW_CFG: 0x%08x", read_buf);

	if (turbo_mode)
		read_buf |= (HW_CFG_MEF_ | HW_CFG_BCE_);

	read_buf &= ~HW_CFG_RXDOFF_;

	/* set Rx data offset=2, Make IP header aligns on word boundary. */
	read_buf |= NET_IP_ALIGN << 9;

	ret = smsc95xx_write_reg(dev, HW_CFG, read_buf);
	if (ret < 0) {
		devwarn(dev, "Failed to write HW_CFG register, ret=%d", ret);
		return ret;
	}

	ret = smsc95xx_read_reg(dev, HW_CFG, &read_buf);
	if (ret < 0) {
		devwarn(dev, "Failed to read HW_CFG: %d", ret);
		return ret;
	}
	if (netif_msg_ifup(dev))
		devdbg(dev, "Read Value from HW_CFG after writing: 0x%08x",
			read_buf);

	write_buf = 0xFFFFFFFF;
	ret = smsc95xx_write_reg(dev, INT_STS, write_buf);
	if (ret < 0) {
		devwarn(dev, "Failed to write INT_STS register, ret=%d", ret);
		return ret;
	}

	ret = smsc95xx_read_reg(dev, ID_REV, &read_buf);
	if (ret < 0) {
		devwarn(dev, "Failed to read ID_REV: %d", ret);
		return ret;
	}
	if (netif_msg_ifup(dev))
		devdbg(dev, "ID_REV = 0x%08x", read_buf);

	/* Init Tx */
	write_buf = 0;
	ret = smsc95xx_write_reg(dev, FLOW, write_buf);
	if (ret < 0) {
		devwarn(dev, "Failed to write FLOW: %d", ret);
		return ret;
	}

	read_buf = AFC_CFG_DEFAULT;
	ret = smsc95xx_write_reg(dev, AFC_CFG, read_buf);
	if (ret < 0) {
		devwarn(dev, "Failed to write AFC_CFG: %d", ret);
		return ret;
	}

	/* Don't need mac_cr_lock during initialisation */
	ret = smsc95xx_read_reg(dev, MAC_CR, &pdata->mac_cr);
	if (ret < 0) {
		devwarn(dev, "Failed to read MAC_CR: %d", ret);
		return ret;
	}

	/* Init Rx */
	/* Set Vlan */
	write_buf = (u32)ETH_P_8021Q;
	ret = smsc95xx_write_reg(dev, VLAN1, write_buf);
	if (ret < 0) {
		devwarn(dev, "Failed to write VAN1: %d", ret);
		return ret;
	}

	/* Enable or disable checksum offload engines */
	ethtool_op_set_tx_hw_csum(netdev, pdata->use_tx_csum);
	ret = smsc95xx_set_csums(dev);
	if (ret < 0) {
		devwarn(dev, "Failed to set csum offload: %d", ret);
		return ret;
	}

	smsc95xx_set_multicast(dev->net);

	if (smsc95xx_phy_initialize(dev) < 0)
		return -EIO;

	ret = smsc95xx_read_reg(dev, INT_EP_CTL, &read_buf);
	if (ret < 0) {
		devwarn(dev, "Failed to read INT_EP_CTL: %d", ret);
		return ret;
	}

	/* enable PHY interrupts */
	read_buf |= INT_EP_CTL_PHY_INT_;

	ret = smsc95xx_write_reg(dev, INT_EP_CTL, read_buf);
	if (ret < 0) {
		devwarn(dev, "Failed to write INT_EP_CTL: %d", ret);
		return ret;
	}

	smsc95xx_start_tx_path(dev);
	smsc95xx_start_rx_path(dev);

	if (netif_msg_ifup(dev))
		devdbg(dev, "smsc95xx_reset, return 0");
	return 0;
}

static int smsc95xx_bind(struct usbnet *dev, struct usb_interface *intf)
{
	struct smsc95xx_priv *pdata = NULL;
	int ret;

	printk(KERN_INFO SMSC_CHIPNAME " v" SMSC_DRIVER_VERSION "\n");

	ret = usbnet_get_endpoints(dev, intf);
	if (ret < 0) {
		devwarn(dev, "usbnet_get_endpoints failed: %d", ret);
		return ret;
	}

	dev->data[0] = (unsigned long)kzalloc(sizeof(struct smsc95xx_priv),
		GFP_KERNEL);

	pdata = (struct smsc95xx_priv *)(dev->data[0]);
	if (!pdata) {
		devwarn(dev, "Unable to allocate struct smsc95xx_priv");
		return -ENOMEM;
	}

	spin_lock_init(&pdata->mac_cr_lock);

	pdata->use_tx_csum = DEFAULT_TX_CSUM_ENABLE;
	pdata->use_rx_csum = DEFAULT_RX_CSUM_ENABLE;

	/* Init all registers */
	ret = smsc95xx_reset(dev);

	dev->net->do_ioctl = smsc95xx_ioctl;
	dev->net->ethtool_ops = &smsc95xx_ethtool_ops;
	dev->net->set_multicast_list = smsc95xx_set_multicast;
	dev->net->flags |= IFF_MULTICAST;
	dev->net->hard_header_len += SMSC95XX_TX_OVERHEAD;
	return 0;
}

static void smsc95xx_unbind(struct usbnet *dev, struct usb_interface *intf)
{
	struct smsc95xx_priv *pdata = (struct smsc95xx_priv *)(dev->data[0]);
	if (pdata) {
		if (netif_msg_ifdown(dev))
			devdbg(dev, "free pdata");
		kfree(pdata);
		pdata = NULL;
		dev->data[0] = 0;
	}
}

static void smsc95xx_rx_csum_offload(struct sk_buff *skb)
{
	skb->csum = *(u16 *)(skb_tail_pointer(skb) - 2);
	skb->ip_summed = CHECKSUM_COMPLETE;
	skb_trim(skb, skb->len - 2);
}

static int smsc95xx_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
{
	struct smsc95xx_priv *pdata = (struct smsc95xx_priv *)(dev->data[0]);

	while (skb->len > 0) {
		u32 header, align_count;
		struct sk_buff *ax_skb;
		unsigned char *packet;
		u16 size;

		memcpy(&header, skb->data, sizeof(header));
		le32_to_cpus(&header);
		skb_pull(skb, 4 + NET_IP_ALIGN);
		packet = skb->data;

		/* get the packet length */
		size = (u16)((header & RX_STS_FL_) >> 16);
		align_count = (4 - ((size + NET_IP_ALIGN) % 4)) % 4;

		if (unlikely(header & RX_STS_ES_)) {
			if (netif_msg_rx_err(dev))
				devdbg(dev, "Error header=0x%08x", header);
			dev->stats.rx_errors++;
			dev->stats.rx_dropped++;

			if (header & RX_STS_CRC_) {
				dev->stats.rx_crc_errors++;
			} else {
				if (header & (RX_STS_TL_ | RX_STS_RF_))
					dev->stats.rx_frame_errors++;

				if ((header & RX_STS_LE_) &&
					(!(header & RX_STS_FT_)))
					dev->stats.rx_length_errors++;
			}
		} else {
			/* ETH_FRAME_LEN + 4(CRC) + 2(COE) + 4(Vlan) */
			if (unlikely(size > (ETH_FRAME_LEN + 12))) {
				if (netif_msg_rx_err(dev))
					devdbg(dev, "size err header=0x%08x",
						header);
				return 0;
			}

			/* last frame in this batch */
			if (skb->len == size) {
				if (pdata->use_rx_csum)
					smsc95xx_rx_csum_offload(skb);

				skb->truesize = size + sizeof(struct sk_buff);

				return 1;
			}

			ax_skb = skb_clone(skb, GFP_ATOMIC);
			if (unlikely(!ax_skb)) {
				devwarn(dev, "Error allocating skb");
				return 0;
			}

			ax_skb->len = size;
			ax_skb->data = packet;
			skb_set_tail_pointer(ax_skb, size);

			if (pdata->use_rx_csum)
				smsc95xx_rx_csum_offload(ax_skb);

			ax_skb->truesize = size + sizeof(struct sk_buff);

			usbnet_skb_return(dev, ax_skb);
		}

		skb_pull(skb, size);

		/* padding bytes before the next frame starts */
		if (skb->len)
			skb_pull(skb, align_count);
	}

	if (unlikely(skb->len < 0)) {
		devwarn(dev, "invalid rx length<0 %d", skb->len);
		return 0;
	}

	return 1;
}

static u32 smsc95xx_calc_csum_preamble(struct sk_buff *skb)
{
	int len = skb->data - skb->head;
	u16 high_16 = (u16)(skb->csum_offset + skb->csum_start - len);
	u16 low_16 = (u16)(skb->csum_start - len);
	return (high_16 << 16) | low_16;
}

static struct sk_buff *smsc95xx_tx_fixup(struct usbnet *dev,
					 struct sk_buff *skb, gfp_t flags)
{
	struct smsc95xx_priv *pdata = (struct smsc95xx_priv *)(dev->data[0]);
	bool csum = pdata->use_tx_csum && (skb->ip_summed == CHECKSUM_PARTIAL);
	int overhead = csum ? SMSC95XX_TX_OVERHEAD_CSUM : SMSC95XX_TX_OVERHEAD;
	u32 tx_cmd_a, tx_cmd_b;

	/* We do not advertise SG, so skbs should be already linearized */
	BUG_ON(skb_shinfo(skb)->nr_frags);

	if (skb_headroom(skb) < overhead) {
		struct sk_buff *skb2 = skb_copy_expand(skb,
			overhead, 0, flags);
		dev_kfree_skb_any(skb);
		skb = skb2;
		if (!skb)
			return NULL;
	}

	if (csum) {
		u32 csum_preamble = smsc95xx_calc_csum_preamble(skb);
		skb_push(skb, 4);
		memcpy(skb->data, &csum_preamble, 4);
	}

	skb_push(skb, 4);
	tx_cmd_b = (u32)(skb->len - 4);
	if (csum)
		tx_cmd_b |= TX_CMD_B_CSUM_ENABLE;
	cpu_to_le32s(&tx_cmd_b);
	memcpy(skb->data, &tx_cmd_b, 4);

	skb_push(skb, 4);
	tx_cmd_a = (u32)(skb->len - 8) | TX_CMD_A_FIRST_SEG_ |
		TX_CMD_A_LAST_SEG_;
	cpu_to_le32s(&tx_cmd_a);
	memcpy(skb->data, &tx_cmd_a, 4);

	return skb;
}

static const struct driver_info smsc95xx_info = {
	.description	= "smsc95xx USB 2.0 Ethernet",
	.bind		= smsc95xx_bind,
	.unbind		= smsc95xx_unbind,
	.link_reset	= smsc95xx_link_reset,
	.reset		= smsc95xx_reset,
	.rx_fixup	= smsc95xx_rx_fixup,
	.tx_fixup	= smsc95xx_tx_fixup,
	.status		= smsc95xx_status,
	.flags		= FLAG_ETHER,
};

static const struct usb_device_id products[] = {
	{
		/* SMSC9500 USB Ethernet Device */
		USB_DEVICE(0x0424, 0x9500),
		.driver_info = (unsigned long) &smsc95xx_info,
	},
	{ },		/* END */
};
MODULE_DEVICE_TABLE(usb, products);

static struct usb_driver smsc95xx_driver = {
	.name		= "smsc95xx",
	.id_table	= products,
	.probe		= usbnet_probe,
	.suspend	= usbnet_suspend,
	.resume		= usbnet_resume,
	.disconnect	= usbnet_disconnect,
};

static int __init smsc95xx_init(void)
{
	return usb_register(&smsc95xx_driver);
}
module_init(smsc95xx_init);

static void __exit smsc95xx_exit(void)
{
	usb_deregister(&smsc95xx_driver);
}
module_exit(smsc95xx_exit);

MODULE_AUTHOR("Nancy Lin");
MODULE_AUTHOR("Steve Glendinning <steve.glendinning@smsc.com>");
MODULE_DESCRIPTION("SMSC95XX USB 2.0 Ethernet Devices");
MODULE_LICENSE("GPL");