/*
   * Davicom DM96xx USB 10/100Mbps ethernet devices
   *
   * Peter Korsgaard <jacmet@sunsite.dk>
   *
   * This file is licensed under the terms of the GNU General Public License
   * version 2.  This program is licensed "as is" without any warranty of any
   * kind, whether express or implied.
   */
  
  //#define DEBUG
  
  #include <linux/module.h>
  #include <linux/sched.h>
  #include <linux/stddef.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 <linux/slab.h>
  
  /* datasheet:
   http://ptm2.cc.utu.fi/ftp/network/cards/DM9601/From_NET/DM9601-DS-P01-930914.pdf
  */
  
  /* control requests */
  #define DM_READ_REGS	0x00
  #define DM_WRITE_REGS	0x01
  #define DM_READ_MEMS	0x02
  #define DM_WRITE_REG	0x03
  #define DM_WRITE_MEMS	0x05
  #define DM_WRITE_MEM	0x07
  
  /* registers */
  #define DM_NET_CTRL	0x00
  #define DM_RX_CTRL	0x05
  #define DM_SHARED_CTRL	0x0b
  #define DM_SHARED_ADDR	0x0c
  #define DM_SHARED_DATA	0x0d	/* low + high */
  #define DM_PHY_ADDR	0x10	/* 6 bytes */
  #define DM_MCAST_ADDR	0x16	/* 8 bytes */
  #define DM_GPR_CTRL	0x1e
  #define DM_GPR_DATA	0x1f
  #define DM_CHIP_ID	0x2c
  #define DM_MODE_CTRL	0x91	/* only on dm9620 */
  
  /* chip id values */
  #define ID_DM9601	0
  #define ID_DM9620	1
  
  #define DM_MAX_MCAST	64
  #define DM_MCAST_SIZE	8
  #define DM_EEPROM_LEN	256
  #define DM_TX_OVERHEAD	2	/* 2 byte header */
  #define DM_RX_OVERHEAD	7	/* 3 byte header + 4 byte crc tail */
  #define DM_TIMEOUT	1000
  
  static int dm_read(struct usbnet *dev, u8 reg, u16 length, void *data)
  {
  	int err;
  	err = usbnet_read_cmd(dev, DM_READ_REGS,
  			       USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
  			       0, reg, data, length);
  	if(err != length && err >= 0)
  		err = -EINVAL;
  	return err;
  }
  
  static int dm_read_reg(struct usbnet *dev, u8 reg, u8 *value)
  {
  	return dm_read(dev, reg, 1, value);
  }
  
  static int dm_write(struct usbnet *dev, u8 reg, u16 length, void *data)
  {
  	int err;
  	err = usbnet_write_cmd(dev, DM_WRITE_REGS,
  				USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
  				0, reg, data, length);
  
  	if (err >= 0 && err < length)
  		err = -EINVAL;
  	return err;
  }
  
  static int dm_write_reg(struct usbnet *dev, u8 reg, u8 value)
  {
  	return usbnet_write_cmd(dev, DM_WRITE_REG,
  				USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
  				value, reg, NULL, 0);
  }
  
  static void dm_write_async(struct usbnet *dev, u8 reg, u16 length, void *data)
  {
  	usbnet_write_cmd_async(dev, DM_WRITE_REGS,
  			       USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
  			       0, reg, data, length);
  }
  
  static void dm_write_reg_async(struct usbnet *dev, u8 reg, u8 value)
  {
  	usbnet_write_cmd_async(dev, DM_WRITE_REG,
  			       USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
  			       value, reg, NULL, 0);
  }
  
  static int dm_read_shared_word(struct usbnet *dev, int phy, u8 reg, __le16 *value)
  {
  	int ret, i;
  
  	mutex_lock(&dev->phy_mutex);
  
  	dm_write_reg(dev, DM_SHARED_ADDR, phy ? (reg | 0x40) : reg);
  	dm_write_reg(dev, DM_SHARED_CTRL, phy ? 0xc : 0x4);
  
  	for (i = 0; i < DM_TIMEOUT; i++) {
  		u8 tmp = 0;
  
  		udelay(1);
  		ret = dm_read_reg(dev, DM_SHARED_CTRL, &tmp);
  		if (ret < 0)
  			goto out;
  
  		/* ready */
  		if ((tmp & 1) == 0)
  			break;
  	}
  
  	if (i == DM_TIMEOUT) {
  		netdev_err(dev->net, "%s read timed out!
  ", phy ? "phy" : "eeprom");
  		ret = -EIO;
  		goto out;
  	}
  
  	dm_write_reg(dev, DM_SHARED_CTRL, 0x0);
  	ret = dm_read(dev, DM_SHARED_DATA, 2, value);
  
  	netdev_dbg(dev->net, "read shared %d 0x%02x returned 0x%04x, %d
  ",
  		   phy, reg, *value, ret);
  
   out:
  	mutex_unlock(&dev->phy_mutex);
  	return ret;
  }
  
  static int dm_write_shared_word(struct usbnet *dev, int phy, u8 reg, __le16 value)
  {
  	int ret, i;
  
  	mutex_lock(&dev->phy_mutex);
  
  	ret = dm_write(dev, DM_SHARED_DATA, 2, &value);
  	if (ret < 0)
  		goto out;
  
  	dm_write_reg(dev, DM_SHARED_ADDR, phy ? (reg | 0x40) : reg);
  	dm_write_reg(dev, DM_SHARED_CTRL, phy ? 0x1a : 0x12);
  
  	for (i = 0; i < DM_TIMEOUT; i++) {
  		u8 tmp = 0;
  
  		udelay(1);
  		ret = dm_read_reg(dev, DM_SHARED_CTRL, &tmp);
  		if (ret < 0)
  			goto out;
  
  		/* ready */
  		if ((tmp & 1) == 0)
  			break;
  	}
  
  	if (i == DM_TIMEOUT) {
  		netdev_err(dev->net, "%s write timed out!
  ", phy ? "phy" : "eeprom");
  		ret = -EIO;
  		goto out;
  	}
  
  	dm_write_reg(dev, DM_SHARED_CTRL, 0x0);
  
  out:
  	mutex_unlock(&dev->phy_mutex);
  	return ret;
  }
  
  static int dm_read_eeprom_word(struct usbnet *dev, u8 offset, void *value)
  {
  	return dm_read_shared_word(dev, 0, offset, value);
  }
  
  
  
  static int dm9601_get_eeprom_len(struct net_device *dev)
  {
  	return DM_EEPROM_LEN;
  }
  
  static int dm9601_get_eeprom(struct net_device *net,
  			     struct ethtool_eeprom *eeprom, u8 * data)
  {
  	struct usbnet *dev = netdev_priv(net);
  	__le16 *ebuf = (__le16 *) data;
  	int i;
  
  	/* access is 16bit */
  	if ((eeprom->offset % 2) || (eeprom->len % 2))
  		return -EINVAL;
  
  	for (i = 0; i < eeprom->len / 2; i++) {
  		if (dm_read_eeprom_word(dev, eeprom->offset / 2 + i,
  					&ebuf[i]) < 0)
  			return -EINVAL;
  	}
  	return 0;
  }
  
  static int dm9601_mdio_read(struct net_device *netdev, int phy_id, int loc)
  {
  	struct usbnet *dev = netdev_priv(netdev);
  
  	__le16 res;
  
  	if (phy_id) {
  		netdev_dbg(dev->net, "Only internal phy supported
  ");
  		return 0;
  	}
  
  	dm_read_shared_word(dev, 1, loc, &res);
  
  	netdev_dbg(dev->net,
  		   "dm9601_mdio_read() phy_id=0x%02x, loc=0x%02x, returns=0x%04x
  ",
  		   phy_id, loc, le16_to_cpu(res));
  
  	return le16_to_cpu(res);
  }
  
  static void dm9601_mdio_write(struct net_device *netdev, int phy_id, int loc,
  			      int val)
  {
  	struct usbnet *dev = netdev_priv(netdev);
  	__le16 res = cpu_to_le16(val);
  
  	if (phy_id) {
  		netdev_dbg(dev->net, "Only internal phy supported
  ");
  		return;
  	}
  
  	netdev_dbg(dev->net, "dm9601_mdio_write() phy_id=0x%02x, loc=0x%02x, val=0x%04x
  ",
  		   phy_id, loc, val);
  
  	dm_write_shared_word(dev, 1, loc, res);
  }
  
  static void dm9601_get_drvinfo(struct net_device *net,
  			       struct ethtool_drvinfo *info)
  {
  	/* Inherit standard device info */
  	usbnet_get_drvinfo(net, info);
  }
  
  static u32 dm9601_get_link(struct net_device *net)
  {
  	struct usbnet *dev = netdev_priv(net);
  
  	return mii_link_ok(&dev->mii);
  }
  
  static int dm9601_ioctl(struct net_device *net, struct ifreq *rq, int cmd)
  {
  	struct usbnet *dev = netdev_priv(net);
  
  	return generic_mii_ioctl(&dev->mii, if_mii(rq), cmd, NULL);
  }
  
  static const struct ethtool_ops dm9601_ethtool_ops = {
  	.get_drvinfo	= dm9601_get_drvinfo,
  	.get_link	= dm9601_get_link,
  	.get_msglevel	= usbnet_get_msglevel,
  	.set_msglevel	= usbnet_set_msglevel,
  	.get_eeprom_len	= dm9601_get_eeprom_len,
  	.get_eeprom	= dm9601_get_eeprom,
  	.get_settings	= usbnet_get_settings,
  	.set_settings	= usbnet_set_settings,
  	.nway_reset	= usbnet_nway_reset,
  };
  
  static void dm9601_set_multicast(struct net_device *net)
  {
  	struct usbnet *dev = netdev_priv(net);
  	/* We use the 20 byte dev->data for our 8 byte filter buffer
  	 * to avoid allocating memory that is tricky to free later */
  	u8 *hashes = (u8 *) & dev->data;
  	u8 rx_ctl = 0x31;
  
  	memset(hashes, 0x00, DM_MCAST_SIZE);
  	hashes[DM_MCAST_SIZE - 1] |= 0x80;	/* broadcast address */
  
  	if (net->flags & IFF_PROMISC) {
  		rx_ctl |= 0x02;
  	} else if (net->flags & IFF_ALLMULTI ||
  		   netdev_mc_count(net) > DM_MAX_MCAST) {
  		rx_ctl |= 0x08;
  	} else if (!netdev_mc_empty(net)) {
  		struct netdev_hw_addr *ha;
  
  		netdev_for_each_mc_addr(ha, net) {
  			u32 crc = ether_crc(ETH_ALEN, ha->addr) >> 26;
  			hashes[crc >> 3] |= 1 << (crc & 0x7);
  		}
  	}
  
  	dm_write_async(dev, DM_MCAST_ADDR, DM_MCAST_SIZE, hashes);
  	dm_write_reg_async(dev, DM_RX_CTRL, rx_ctl);
  }
  
  static void __dm9601_set_mac_address(struct usbnet *dev)
  {
  	dm_write_async(dev, DM_PHY_ADDR, ETH_ALEN, dev->net->dev_addr);
  }
  
  static int dm9601_set_mac_address(struct net_device *net, void *p)
  {
  	struct sockaddr *addr = p;
  	struct usbnet *dev = netdev_priv(net);
  
  	if (!is_valid_ether_addr(addr->sa_data)) {
  		dev_err(&net->dev, "not setting invalid mac address %pM
  ",
  								addr->sa_data);
  		return -EINVAL;
  	}
  
  	memcpy(net->dev_addr, addr->sa_data, net->addr_len);
  	__dm9601_set_mac_address(dev);
  
  	return 0;
  }
  
  static const struct net_device_ops dm9601_netdev_ops = {
  	.ndo_open		= usbnet_open,
  	.ndo_stop		= usbnet_stop,
  	.ndo_start_xmit		= usbnet_start_xmit,
  	.ndo_tx_timeout		= usbnet_tx_timeout,
  	.ndo_change_mtu		= usbnet_change_mtu,
  	.ndo_validate_addr	= eth_validate_addr,
  	.ndo_do_ioctl 		= dm9601_ioctl,
  	.ndo_set_rx_mode	= dm9601_set_multicast,
  	.ndo_set_mac_address	= dm9601_set_mac_address,
  };
  
  static int dm9601_bind(struct usbnet *dev, struct usb_interface *intf)
  {
  	int ret;
  	u8 mac[ETH_ALEN], id;
  
  	ret = usbnet_get_endpoints(dev, intf);
  	if (ret)
  		goto out;
  
  	dev->net->netdev_ops = &dm9601_netdev_ops;
  	dev->net->ethtool_ops = &dm9601_ethtool_ops;
  	dev->net->hard_header_len += DM_TX_OVERHEAD;
  	dev->hard_mtu = dev->net->mtu + dev->net->hard_header_len;
  
  	/* dm9620/21a require room for 4 byte padding, even in dm9601
  	 * mode, so we need +1 to be able to receive full size
  	 * ethernet frames.
  	 */
  	dev->rx_urb_size = dev->net->mtu + ETH_HLEN + DM_RX_OVERHEAD + 1;
  
  	dev->mii.dev = dev->net;
  	dev->mii.mdio_read = dm9601_mdio_read;
  	dev->mii.mdio_write = dm9601_mdio_write;
  	dev->mii.phy_id_mask = 0x1f;
  	dev->mii.reg_num_mask = 0x1f;
  
  	/* reset */
  	dm_write_reg(dev, DM_NET_CTRL, 1);
  	udelay(20);
  
  	/* read MAC */
  	if (dm_read(dev, DM_PHY_ADDR, ETH_ALEN, mac) < 0) {
  		printk(KERN_ERR "Error reading MAC address
  ");
  		ret = -ENODEV;
  		goto out;
  	}
  
  	/*
  	 * Overwrite the auto-generated address only with good ones.
  	 */
  	if (is_valid_ether_addr(mac))
  		memcpy(dev->net->dev_addr, mac, ETH_ALEN);
  	else {
  		printk(KERN_WARNING
  			"dm9601: No valid MAC address in EEPROM, using %pM
  ",
  			dev->net->dev_addr);
  		__dm9601_set_mac_address(dev);
  	}
  
  	if (dm_read_reg(dev, DM_CHIP_ID, &id) < 0) {
  		netdev_err(dev->net, "Error reading chip ID
  ");
  		ret = -ENODEV;
  		goto out;
  	}
  
  	/* put dm9620 devices in dm9601 mode */
  	if (id == ID_DM9620) {
  		u8 mode;
  
  		if (dm_read_reg(dev, DM_MODE_CTRL, &mode) < 0) {
  			netdev_err(dev->net, "Error reading MODE_CTRL
  ");
  			ret = -ENODEV;
  			goto out;
  		}
  		dm_write_reg(dev, DM_MODE_CTRL, mode & 0x7f);
  	}
  
  	/* power up phy */
  	dm_write_reg(dev, DM_GPR_CTRL, 1);
  	dm_write_reg(dev, DM_GPR_DATA, 0);
  
  	/* receive broadcast packets */
  	dm9601_set_multicast(dev->net);
  
  	dm9601_mdio_write(dev->net, dev->mii.phy_id, MII_BMCR, BMCR_RESET);
  	dm9601_mdio_write(dev->net, dev->mii.phy_id, MII_ADVERTISE,
  			  ADVERTISE_ALL | ADVERTISE_CSMA | ADVERTISE_PAUSE_CAP);
  	mii_nway_restart(&dev->mii);
  
  out:
  	return ret;
  }
  
  static int dm9601_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
  {
  	u8 status;
  	int len;
  
  	/* format:
  	   b1: rx status
  	   b2: packet length (incl crc) low
  	   b3: packet length (incl crc) high
  	   b4..n-4: packet data
  	   bn-3..bn: ethernet crc
  	 */
  
  	if (unlikely(skb->len < DM_RX_OVERHEAD)) {
  		dev_err(&dev->udev->dev, "unexpected tiny rx frame
  ");
  		return 0;
  	}
  
  	status = skb->data[0];
  	len = (skb->data[1] | (skb->data[2] << 8)) - 4;
  
  	if (unlikely(status & 0xbf)) {
  		if (status & 0x01) dev->net->stats.rx_fifo_errors++;
  		if (status & 0x02) dev->net->stats.rx_crc_errors++;
  		if (status & 0x04) dev->net->stats.rx_frame_errors++;
  		if (status & 0x20) dev->net->stats.rx_missed_errors++;
  		if (status & 0x90) dev->net->stats.rx_length_errors++;
  		return 0;
  	}
  
  	skb_pull(skb, 3);
  	skb_trim(skb, len);
  
  	return 1;
  }
  
  static struct sk_buff *dm9601_tx_fixup(struct usbnet *dev, struct sk_buff *skb,
  				       gfp_t flags)
  {
  	int len, pad;
  
  	/* format:
  	   b1: packet length low
  	   b2: packet length high
  	   b3..n: packet data
  	*/
  
  	len = skb->len + DM_TX_OVERHEAD;
  
  	/* workaround for dm962x errata with tx fifo getting out of
  	 * sync if a USB bulk transfer retry happens right after a
  	 * packet with odd / maxpacket length by adding up to 3 bytes
  	 * padding.
  	 */
  	while ((len & 1) || !(len % dev->maxpacket))
  		len++;
  
  	len -= DM_TX_OVERHEAD; /* hw header doesn't count as part of length */
  	pad = len - skb->len;
  
  	if (skb_headroom(skb) < DM_TX_OVERHEAD || skb_tailroom(skb) < pad) {
  		struct sk_buff *skb2;
  
  		skb2 = skb_copy_expand(skb, DM_TX_OVERHEAD, pad, flags);
  		dev_kfree_skb_any(skb);
  		skb = skb2;
  		if (!skb)
  			return NULL;
  	}
  
  	__skb_push(skb, DM_TX_OVERHEAD);
  
  	if (pad) {
  		memset(skb->data + skb->len, 0, pad);
  		__skb_put(skb, pad);
  	}
  
  	skb->data[0] = len;
  	skb->data[1] = len >> 8;
  
  	return skb;
  }
  
  static void dm9601_status(struct usbnet *dev, struct urb *urb)
  {
  	int link;
  	u8 *buf;
  
  	/* format:
  	   b0: net status
  	   b1: tx status 1
  	   b2: tx status 2
  	   b3: rx status
  	   b4: rx overflow
  	   b5: rx count
  	   b6: tx count
  	   b7: gpr
  	*/
  
  	if (urb->actual_length < 8)
  		return;
  
  	buf = urb->transfer_buffer;
  
  	link = !!(buf[0] & 0x40);
  	if (netif_carrier_ok(dev->net) != link) {
  		usbnet_link_change(dev, link, 1);
  		netdev_dbg(dev->net, "Link Status is: %d
  ", link);
  	}
  }
  
  static int dm9601_link_reset(struct usbnet *dev)
  {
  	struct ethtool_cmd ecmd = { .cmd = ETHTOOL_GSET };
  
  	mii_check_media(&dev->mii, 1, 1);
  	mii_ethtool_gset(&dev->mii, &ecmd);
  
  	netdev_dbg(dev->net, "link_reset() speed: %u duplex: %d
  ",
  		   ethtool_cmd_speed(&ecmd), ecmd.duplex);
  
  	return 0;
  }
  
  static const struct driver_info dm9601_info = {
  	.description	= "Davicom DM96xx USB 10/100 Ethernet",
  	.flags		= FLAG_ETHER | FLAG_LINK_INTR,
  	.bind		= dm9601_bind,
  	.rx_fixup	= dm9601_rx_fixup,
  	.tx_fixup	= dm9601_tx_fixup,
  	.status		= dm9601_status,
  	.link_reset	= dm9601_link_reset,
  	.reset		= dm9601_link_reset,
  };
  
  static const struct usb_device_id products[] = {
  	{
  	 USB_DEVICE(0x07aa, 0x9601),	/* Corega FEther USB-TXC */
  	 .driver_info = (unsigned long)&dm9601_info,
  	 },
  	{
  	 USB_DEVICE(0x0a46, 0x9601),	/* Davicom USB-100 */
  	 .driver_info = (unsigned long)&dm9601_info,
  	 },
  	{
  	 USB_DEVICE(0x0a46, 0x6688),	/* ZT6688 USB NIC */
  	 .driver_info = (unsigned long)&dm9601_info,
  	 },
  	{
  	 USB_DEVICE(0x0a46, 0x0268),	/* ShanTou ST268 USB NIC */
  	 .driver_info = (unsigned long)&dm9601_info,
  	 },
  	{
  	 USB_DEVICE(0x0a46, 0x8515),	/* ADMtek ADM8515 USB NIC */
  	 .driver_info = (unsigned long)&dm9601_info,
  	 },
  	{
  	USB_DEVICE(0x0a47, 0x9601),	/* Hirose USB-100 */
  	.driver_info = (unsigned long)&dm9601_info,
  	 },
  	{
  	USB_DEVICE(0x0fe6, 0x8101),	/* DM9601 USB to Fast Ethernet Adapter */
  	.driver_info = (unsigned long)&dm9601_info,
  	 },
  	{
  	 USB_DEVICE(0x0fe6, 0x9700),	/* DM9601 USB to Fast Ethernet Adapter */
  	 .driver_info = (unsigned long)&dm9601_info,
  	 },
  	{
  	 USB_DEVICE(0x0a46, 0x9000),	/* DM9000E */
  	 .driver_info = (unsigned long)&dm9601_info,
  	 },
  	{
  	 USB_DEVICE(0x0a46, 0x9620),	/* DM9620 USB to Fast Ethernet Adapter */
  	 .driver_info = (unsigned long)&dm9601_info,
  	 },
  	{
  	 USB_DEVICE(0x0a46, 0x9621),	/* DM9621A USB to Fast Ethernet Adapter */
  	 .driver_info = (unsigned long)&dm9601_info,
  	},
  	{
  	 USB_DEVICE(0x0a46, 0x9622),	/* DM9622 USB to Fast Ethernet Adapter */
  	 .driver_info = (unsigned long)&dm9601_info,
  	},
  	{
  	 USB_DEVICE(0x0a46, 0x0269),	/* DM962OA USB to Fast Ethernet Adapter */
  	 .driver_info = (unsigned long)&dm9601_info,
  	},
  	{
  	 USB_DEVICE(0x0a46, 0x1269),	/* DM9621A USB to Fast Ethernet Adapter */
  	 .driver_info = (unsigned long)&dm9601_info,
  	},
  	{},			// END
  };
  
  MODULE_DEVICE_TABLE(usb, products);
  
  static struct usb_driver dm9601_driver = {
  	.name = "dm9601",
  	.id_table = products,
  	.probe = usbnet_probe,
  	.disconnect = usbnet_disconnect,
  	.suspend = usbnet_suspend,
  	.resume = usbnet_resume,
  	.disable_hub_initiated_lpm = 1,
  };
  
  module_usb_driver(dm9601_driver);
  
  MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>");
  MODULE_DESCRIPTION("Davicom DM96xx USB 10/100 ethernet devices");
  MODULE_LICENSE("GPL");