/*
 * ASIX AX8817X based USB 2.0 Ethernet Devices
 * Copyright (C) 2003-2006 David Hollis <dhollis@davehollis.com>
 * Copyright (C) 2005 Phil Chang <pchang23@sbcglobal.net>
 * Copyright (C) 2006 James Painter <jamie.painter@iname.com>
 * Copyright (c) 2002-2003 TiVo Inc.
 *
 * 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, see <http://www.gnu.org/licenses/>.
 */

#include "asix.h"

int asix_read_cmd(struct usbnet *dev, u8 cmd, u16 value, u16 index,
                  u16 size, void *data)
{
        int ret;
        ret = usbnet_read_cmd(dev, cmd,
                               USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
                               value, index, data, size);

        if (ret != size && ret >= 0)
                return -EINVAL;
        return ret;
}

int asix_write_cmd(struct usbnet *dev, u8 cmd, u16 value, u16 index,
                   u16 size, void *data)
{
        return usbnet_write_cmd(dev, cmd,
                                USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
                                value, index, data, size);
}

void asix_write_cmd_async(struct usbnet *dev, u8 cmd, u16 value, u16 index,
                          u16 size, void *data)
{
        usbnet_write_cmd_async(dev, cmd,
                               USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
                               value, index, data, size);
}

int asix_rx_fixup_internal(struct usbnet *dev, struct sk_buff *skb,
                           struct asix_rx_fixup_info *rx)
{
        int offset = 0;
        u16 size;

        /* When an Ethernet frame spans multiple URB socket buffers,
         * do a sanity test for the Data header synchronisation.
         * Attempt to detect the situation of the previous socket buffer having
         * been truncated or a socket buffer was missing. These situations
         * cause a discontinuity in the data stream and therefore need to avoid
         * appending bad data to the end of the current netdev socket buffer.
         * Also avoid unnecessarily discarding a good current netdev socket
         * buffer.
         */
        if (rx->remaining && (rx->remaining + sizeof(u32) <= skb->len)) {
                offset = ((rx->remaining + 1) & 0xfffe);
                rx->header = get_unaligned_le32(skb->data + offset);
                offset = 0;

                size = (u16)(rx->header & 0x7ff);
                if (size != ((~rx->header >> 16) & 0x7ff)) {
                        netdev_err(dev->net, "asix_rx_fixup() Data Header synchronisation was lost, remaining %d\n",
                                   rx->remaining);
                        if (rx->ax_skb) {
                                kfree_skb(rx->ax_skb);
                                rx->ax_skb = NULL;
                                /* Discard the incomplete netdev Ethernet frame
                                 * and assume the Data header is at the start of
                                 * the current URB socket buffer.
                                 */
                        }
                        rx->remaining = 0;
                }
        }

        while (offset + sizeof(u16) <= skb->len) {
                u16 copy_length;
                unsigned char *data;

                if (!rx->remaining) {
                        if (skb->len - offset == sizeof(u16)) {
                                rx->header = get_unaligned_le16(
                                                skb->data + offset);
                                rx->split_head = true;
                                offset += sizeof(u16);
                                break;
                        }

                        if (rx->split_head == true) {
                                rx->header |= (get_unaligned_le16(
                                                skb->data + offset) << 16);
                                rx->split_head = false;
                                offset += sizeof(u16);
                        } else {
                                rx->header = get_unaligned_le32(skb->data +
                                                                offset);
                                offset += sizeof(u32);
                        }

                        /* take frame length from Data header 32-bit word */
                        size = (u16)(rx->header & 0x7ff);
                        if (size != ((~rx->header >> 16) & 0x7ff)) {
                                netdev_err(dev->net, "asix_rx_fixup() Bad Header Length 0x%x, offset %d\n",
                                           rx->header, offset);
                                return 0;
                        }
                        if (size > dev->net->mtu + ETH_HLEN + VLAN_HLEN) {
                                netdev_dbg(dev->net, "asix_rx_fixup() Bad RX Length %d\n",
                                           size);
                                return 0;
                        }

                        /* Sometimes may fail to get a netdev socket buffer but
                         * continue to process the URB socket buffer so that
                         * synchronisation of the Ethernet frame Data header
                         * word is maintained.
                         */
                        rx->ax_skb = netdev_alloc_skb_ip_align(dev->net, size);

                        rx->remaining = size;
                }

                if (rx->remaining > skb->len - offset) {
                        copy_length = skb->len - offset;
                        rx->remaining -= copy_length;
                } else {
                        copy_length = rx->remaining;
                        rx->remaining = 0;
                }

                if (rx->ax_skb) {
                        data = skb_put(rx->ax_skb, copy_length);
                        memcpy(data, skb->data + offset, copy_length);
                        if (!rx->remaining)
                                usbnet_skb_return(dev, rx->ax_skb);
                }

                offset += (copy_length + 1) & 0xfffe;
        }

        if (skb->len != offset) {
                netdev_err(dev->net, "asix_rx_fixup() Bad SKB Length %d, %d\n",
                           skb->len, offset);
                return 0;
        }

        return 1;
}

int asix_rx_fixup_common(struct usbnet *dev, struct sk_buff *skb)
{
        struct asix_common_private *dp = dev->driver_priv;
        struct asix_rx_fixup_info *rx = &dp->rx_fixup_info;

        return asix_rx_fixup_internal(dev, skb, rx);
}

struct sk_buff *asix_tx_fixup(struct usbnet *dev, struct sk_buff *skb,
                              gfp_t flags)
{
        int padlen;
        int headroom = skb_headroom(skb);
        int tailroom = skb_tailroom(skb);
        u32 packet_len;
        u32 padbytes = 0xffff0000;

        padlen = ((skb->len + 4) & (dev->maxpacket - 1)) ? 0 : 4;

        /* We need to push 4 bytes in front of frame (packet_len)
         * and maybe add 4 bytes after the end (if padlen is 4)
         *
         * Avoid skb_copy_expand() expensive call, using following rules :
         * - We are allowed to push 4 bytes in headroom if skb_header_cloned()
         *   is false (and if we have 4 bytes of headroom)
         * - We are allowed to put 4 bytes at tail if skb_cloned()
         *   is false (and if we have 4 bytes of tailroom)
         *
         * TCP packets for example are cloned, but skb_header_release()
         * was called in tcp stack, allowing us to use headroom for our needs.
         */
        if (!skb_header_cloned(skb) &&
            !(padlen && skb_cloned(skb)) &&
            headroom + tailroom >= 4 + padlen) {
                /* following should not happen, but better be safe */
                if (headroom < 4 ||
                    tailroom < padlen) {
                        skb->data = memmove(skb->head + 4, skb->data, skb->len);
                        skb_set_tail_pointer(skb, skb->len);
                }
        } else {
                struct sk_buff *skb2;

                skb2 = skb_copy_expand(skb, 4, padlen, flags);
                dev_kfree_skb_any(skb);
                skb = skb2;
                if (!skb)
                        return NULL;
        }

        packet_len = ((skb->len ^ 0x0000ffff) << 16) + skb->len;
        skb_push(skb, 4);
        cpu_to_le32s(&packet_len);
        skb_copy_to_linear_data(skb, &packet_len, sizeof(packet_len));

        if (padlen) {
                cpu_to_le32s(&padbytes);
                memcpy(skb_tail_pointer(skb), &padbytes, sizeof(padbytes));
                skb_put(skb, sizeof(padbytes));
        }

        usbnet_set_skb_tx_stats(skb, 1, 0);
        return skb;
}

int asix_set_sw_mii(struct usbnet *dev)
{
        int ret;
        ret = asix_write_cmd(dev, AX_CMD_SET_SW_MII, 0x0000, 0, 0, NULL);
        if (ret < 0)
                netdev_err(dev->net, "Failed to enable software MII access\n");
        return ret;
}

int asix_set_hw_mii(struct usbnet *dev)
{
        int ret;
        ret = asix_write_cmd(dev, AX_CMD_SET_HW_MII, 0x0000, 0, 0, NULL);
        if (ret < 0)
                netdev_err(dev->net, "Failed to enable hardware MII access\n");
        return ret;
}

int asix_read_phy_addr(struct usbnet *dev, int internal)
{
        int offset = (internal ? 1 : 0);
        u8 buf[2];
        int ret = asix_read_cmd(dev, AX_CMD_READ_PHY_ID, 0, 0, 2, buf);

        netdev_dbg(dev->net, "asix_get_phy_addr()\n");

        if (ret < 0) {
                netdev_err(dev->net, "Error reading PHYID register: %02x\n", ret);
                goto out;
        }
        netdev_dbg(dev->net, "asix_get_phy_addr() returning 0x%04x\n",
                   *((__le16 *)buf));
        ret = buf[offset];

out:
        return ret;
}

int asix_get_phy_addr(struct usbnet *dev)
{
        /* return the address of the internal phy */
        return asix_read_phy_addr(dev, 1);
}


int asix_sw_reset(struct usbnet *dev, u8 flags)
{
        int ret;

        ret = asix_write_cmd(dev, AX_CMD_SW_RESET, flags, 0, 0, NULL);
        if (ret < 0)
                netdev_err(dev->net, "Failed to send software reset: %02x\n", ret);

        return ret;
}

u16 asix_read_rx_ctl(struct usbnet *dev)
{
        __le16 v;
        int ret = asix_read_cmd(dev, AX_CMD_READ_RX_CTL, 0, 0, 2, &v);

        if (ret < 0) {
                netdev_err(dev->net, "Error reading RX_CTL register: %02x\n", ret);
                goto out;
        }
        ret = le16_to_cpu(v);
out:
        return ret;
}

int asix_write_rx_ctl(struct usbnet *dev, u16 mode)
{
        int ret;

        netdev_dbg(dev->net, "asix_write_rx_ctl() - mode = 0x%04x\n", mode);
        ret = asix_write_cmd(dev, AX_CMD_WRITE_RX_CTL, mode, 0, 0, NULL);
        if (ret < 0)
                netdev_err(dev->net, "Failed to write RX_CTL mode to 0x%04x: %02x\n",
                           mode, ret);

        return ret;
}

u16 asix_read_medium_status(struct usbnet *dev)
{
        __le16 v;
        int ret = asix_read_cmd(dev, AX_CMD_READ_MEDIUM_STATUS, 0, 0, 2, &v);

        if (ret < 0) {
                netdev_err(dev->net, "Error reading Medium Status register: %02x\n",
                           ret);
                return ret;     /* TODO: callers not checking for error ret */
        }

        return le16_to_cpu(v);

}

int asix_write_medium_mode(struct usbnet *dev, u16 mode)
{
        int ret;

        netdev_dbg(dev->net, "asix_write_medium_mode() - mode = 0x%04x\n", mode);
        ret = asix_write_cmd(dev, AX_CMD_WRITE_MEDIUM_MODE, mode, 0, 0, NULL);
        if (ret < 0)
                netdev_err(dev->net, "Failed to write Medium Mode mode to 0x%04x: %02x\n",
                           mode, ret);

        return ret;
}

int asix_write_gpio(struct usbnet *dev, u16 value, int sleep)
{
        int ret;

        netdev_dbg(dev->net, "asix_write_gpio() - value = 0x%04x\n", value);
        ret = asix_write_cmd(dev, AX_CMD_WRITE_GPIOS, value, 0, 0, NULL);
        if (ret < 0)
                netdev_err(dev->net, "Failed to write GPIO value 0x%04x: %02x\n",
                           value, ret);

        if (sleep)
                msleep(sleep);

        return ret;
}

/*
 * AX88772 & AX88178 have a 16-bit RX_CTL value
 */
void asix_set_multicast(struct net_device *net)
{
        struct usbnet *dev = netdev_priv(net);
        struct asix_data *data = (struct asix_data *)&dev->data;
        u16 rx_ctl = AX_DEFAULT_RX_CTL;

        if (net->flags & IFF_PROMISC) {
                rx_ctl |= AX_RX_CTL_PRO;
        } else if (net->flags & IFF_ALLMULTI ||
                   netdev_mc_count(net) > AX_MAX_MCAST) {
                rx_ctl |= AX_RX_CTL_AMALL;
        } else if (netdev_mc_empty(net)) {
                /* just broadcast and directed */
        } else {
                /* We use the 20 byte dev->data
                 * for our 8 byte filter buffer
                 * to avoid allocating memory that
                 * is tricky to free later */
                struct netdev_hw_addr *ha;
                u32 crc_bits;

                memset(data->multi_filter, 0, AX_MCAST_FILTER_SIZE);

                /* Build the multicast hash filter. */
                netdev_for_each_mc_addr(ha, net) {
                        crc_bits = ether_crc(ETH_ALEN, ha->addr) >> 26;
                        data->multi_filter[crc_bits >> 3] |=
                            1 << (crc_bits & 7);
                }

                asix_write_cmd_async(dev, AX_CMD_WRITE_MULTI_FILTER, 0, 0,
                                   AX_MCAST_FILTER_SIZE, data->multi_filter);

                rx_ctl |= AX_RX_CTL_AM;
        }

        asix_write_cmd_async(dev, AX_CMD_WRITE_RX_CTL, rx_ctl, 0, 0, NULL);
}

int asix_mdio_read(struct net_device *netdev, int phy_id, int loc)
{
        struct usbnet *dev = netdev_priv(netdev);
        __le16 res;

        mutex_lock(&dev->phy_mutex);
        asix_set_sw_mii(dev);
        asix_read_cmd(dev, AX_CMD_READ_MII_REG, phy_id,
                                (__u16)loc, 2, &res);
        asix_set_hw_mii(dev);
        mutex_unlock(&dev->phy_mutex);

        netdev_dbg(dev->net, "asix_mdio_read() phy_id=0x%02x, loc=0x%02x, returns=0x%04x\n",
                   phy_id, loc, le16_to_cpu(res));

        return le16_to_cpu(res);
}

void asix_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);

        netdev_dbg(dev->net, "asix_mdio_write() phy_id=0x%02x, loc=0x%02x, val=0x%04x\n",
                   phy_id, loc, val);
        mutex_lock(&dev->phy_mutex);
        asix_set_sw_mii(dev);
        asix_write_cmd(dev, AX_CMD_WRITE_MII_REG, phy_id, (__u16)loc, 2, &res);
        asix_set_hw_mii(dev);
        mutex_unlock(&dev->phy_mutex);
}

void asix_get_wol(struct net_device *net, struct ethtool_wolinfo *wolinfo)
{
        struct usbnet *dev = netdev_priv(net);
        u8 opt;

        if (asix_read_cmd(dev, AX_CMD_READ_MONITOR_MODE, 0, 0, 1, &opt) < 0) {
                wolinfo->supported = 0;
                wolinfo->wolopts = 0;
                return;
        }
        wolinfo->supported = WAKE_PHY | WAKE_MAGIC;
        wolinfo->wolopts = 0;
        if (opt & AX_MONITOR_LINK)
                wolinfo->wolopts |= WAKE_PHY;
        if (opt & AX_MONITOR_MAGIC)
                wolinfo->wolopts |= WAKE_MAGIC;
}

int asix_set_wol(struct net_device *net, struct ethtool_wolinfo *wolinfo)
{
        struct usbnet *dev = netdev_priv(net);
        u8 opt = 0;

        if (wolinfo->wolopts & WAKE_PHY)
                opt |= AX_MONITOR_LINK;
        if (wolinfo->wolopts & WAKE_MAGIC)
                opt |= AX_MONITOR_MAGIC;

        if (asix_write_cmd(dev, AX_CMD_WRITE_MONITOR_MODE,
                              opt, 0, 0, NULL) < 0)
                return -EINVAL;

        return 0;
}

int asix_get_eeprom_len(struct net_device *net)
{
        return AX_EEPROM_LEN;
}

int asix_get_eeprom(struct net_device *net, struct ethtool_eeprom *eeprom,
                    u8 *data)
{
        struct usbnet *dev = netdev_priv(net);
        u16 *eeprom_buff;
        int first_word, last_word;
        int i;

        if (eeprom->len == 0)
                return -EINVAL;

        eeprom->magic = AX_EEPROM_MAGIC;

        first_word = eeprom->offset >> 1;
        last_word = (eeprom->offset + eeprom->len - 1) >> 1;

        eeprom_buff = kmalloc(sizeof(u16) * (last_word - first_word + 1),
                              GFP_KERNEL);
        if (!eeprom_buff)
                return -ENOMEM;

        /* ax8817x returns 2 bytes from eeprom on read */
        for (i = first_word; i <= last_word; i++) {
                if (asix_read_cmd(dev, AX_CMD_READ_EEPROM, i, 0, 2,
                                  &(eeprom_buff[i - first_word])) < 0) {
                        kfree(eeprom_buff);
                        return -EIO;
                }
        }

        memcpy(data, (u8 *)eeprom_buff + (eeprom->offset & 1), eeprom->len);
        kfree(eeprom_buff);
        return 0;
}

int asix_set_eeprom(struct net_device *net, struct ethtool_eeprom *eeprom,
                    u8 *data)
{
        struct usbnet *dev = netdev_priv(net);
        u16 *eeprom_buff;
        int first_word, last_word;
        int i;
        int ret;

        netdev_dbg(net, "write EEPROM len %d, offset %d, magic 0x%x\n",
                   eeprom->len, eeprom->offset, eeprom->magic);

        if (eeprom->len == 0)
                return -EINVAL;

        if (eeprom->magic != AX_EEPROM_MAGIC)
                return -EINVAL;

        first_word = eeprom->offset >> 1;
        last_word = (eeprom->offset + eeprom->len - 1) >> 1;

        eeprom_buff = kmalloc(sizeof(u16) * (last_word - first_word + 1),
                              GFP_KERNEL);
        if (!eeprom_buff)
                return -ENOMEM;

        /* align data to 16 bit boundaries, read the missing data from
           the EEPROM */
        if (eeprom->offset & 1) {
                ret = asix_read_cmd(dev, AX_CMD_READ_EEPROM, first_word, 0, 2,
                                    &(eeprom_buff[0]));
                if (ret < 0) {
                        netdev_err(net, "Failed to read EEPROM at offset 0x%02x.\n", first_word);
                        goto free;
                }
        }

        if ((eeprom->offset + eeprom->len) & 1) {
                ret = asix_read_cmd(dev, AX_CMD_READ_EEPROM, last_word, 0, 2,
                                    &(eeprom_buff[last_word - first_word]));
                if (ret < 0) {
                        netdev_err(net, "Failed to read EEPROM at offset 0x%02x.\n", last_word);
                        goto free;
                }
        }

        memcpy((u8 *)eeprom_buff + (eeprom->offset & 1), data, eeprom->len);

        /* write data to EEPROM */
        ret = asix_write_cmd(dev, AX_CMD_WRITE_ENABLE, 0x0000, 0, 0, NULL);
        if (ret < 0) {
                netdev_err(net, "Failed to enable EEPROM write\n");
                goto free;
        }
        msleep(20);

        for (i = first_word; i <= last_word; i++) {
                netdev_dbg(net, "write to EEPROM at offset 0x%02x, data 0x%04x\n",
                           i, eeprom_buff[i - first_word]);
                ret = asix_write_cmd(dev, AX_CMD_WRITE_EEPROM, i,
                                     eeprom_buff[i - first_word], 0, NULL);
                if (ret < 0) {
                        netdev_err(net, "Failed to write EEPROM at offset 0x%02x.\n",
                                   i);
                        goto free;
                }
                msleep(20);
        }

        ret = asix_write_cmd(dev, AX_CMD_WRITE_DISABLE, 0x0000, 0, 0, NULL);
        if (ret < 0) {
                netdev_err(net, "Failed to disable EEPROM write\n");
                goto free;
        }

        ret = 0;
free:
        kfree(eeprom_buff);
        return ret;
}

void asix_get_drvinfo(struct net_device *net, struct ethtool_drvinfo *info)
{
        /* Inherit standard device info */
        usbnet_get_drvinfo(net, info);
        strlcpy(info->driver, DRIVER_NAME, sizeof(info->driver));
        strlcpy(info->version, DRIVER_VERSION, sizeof(info->version));
}

int asix_set_mac_address(struct net_device *net, void *p)
{
        struct usbnet *dev = netdev_priv(net);
        struct asix_data *data = (struct asix_data *)&dev->data;
        struct sockaddr *addr = p;

        if (netif_running(net))
                return -EBUSY;
        if (!is_valid_ether_addr(addr->sa_data))
                return -EADDRNOTAVAIL;

        memcpy(net->dev_addr, addr->sa_data, ETH_ALEN);

        /* We use the 20 byte dev->data
         * for our 6 byte mac buffer
         * to avoid allocating memory that
         * is tricky to free later */
        memcpy(data->mac_addr, addr->sa_data, ETH_ALEN);
        asix_write_cmd_async(dev, AX_CMD_WRITE_NODE_ID, 0, 0, ETH_ALEN,
                                                        data->mac_addr);

        return 0;
}