/*
 *  Atheros Communication Bluetooth HCIATH3K UART protocol
 *
 *  HCIATH3K (HCI Atheros AR300x Protocol) is a Atheros Communication's
 *  power management protocol extension to H4 to support AR300x Bluetooth Chip.
 *
 *  Copyright (c) 2009-2010 Atheros Communications Inc.
 *
 *  Acknowledgements:
 *  This file is based on hci_h4.c, which was written
 *  by Maxim Krasnyansky and Marcel Holtmann.
 *
 *  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/kernel.h>

#include <linux/init.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/errno.h>
#include <linux/ioctl.h>
#include <linux/skbuff.h>

#include <net/bluetooth/bluetooth.h>
#include <net/bluetooth/hci_core.h>

#include "hci_uart.h"

struct ath_struct {
        struct hci_uart *hu;
        unsigned int cur_sleep;

        struct sk_buff_head txq;
        struct work_struct ctxtsw;
};

static int ath_wakeup_ar3k(struct tty_struct *tty)
{
        struct ktermios ktermios;
        int status = tty->driver->ops->tiocmget(tty);

        if (status & TIOCM_CTS)
                return status;

        /* Disable Automatic RTSCTS */
        memcpy(&ktermios, tty->termios, sizeof(ktermios));
        ktermios.c_cflag &= ~CRTSCTS;
        tty_set_termios(tty, &ktermios);

        /* Clear RTS first */
        status = tty->driver->ops->tiocmget(tty);
        tty->driver->ops->tiocmset(tty, 0x00, TIOCM_RTS);
        mdelay(20);

        /* Set RTS, wake up board */
        status = tty->driver->ops->tiocmget(tty);
        tty->driver->ops->tiocmset(tty, TIOCM_RTS, 0x00);
        mdelay(20);

        status = tty->driver->ops->tiocmget(tty);

        /* Disable Automatic RTSCTS */
        ktermios.c_cflag |= CRTSCTS;
        status = tty_set_termios(tty, &ktermios);

        return status;
}

static void ath_hci_uart_work(struct work_struct *work)
{
        int status;
        struct ath_struct *ath;
        struct hci_uart *hu;
        struct tty_struct *tty;

        ath = container_of(work, struct ath_struct, ctxtsw);

        hu = ath->hu;
        tty = hu->tty;

        /* verify and wake up controller */
        if (ath->cur_sleep) {
                status = ath_wakeup_ar3k(tty);
                if (!(status & TIOCM_CTS))
                        return;
        }

        /* Ready to send Data */
        clear_bit(HCI_UART_SENDING, &hu->tx_state);
        hci_uart_tx_wakeup(hu);
}

/* Initialize protocol */
static int ath_open(struct hci_uart *hu)
{
        struct ath_struct *ath;

        BT_DBG("hu %p", hu);

        ath = kzalloc(sizeof(*ath), GFP_ATOMIC);
        if (!ath)
                return -ENOMEM;

        skb_queue_head_init(&ath->txq);

        hu->priv = ath;
        ath->hu = hu;

        INIT_WORK(&ath->ctxtsw, ath_hci_uart_work);

        return 0;
}

/* Flush protocol data */
static int ath_flush(struct hci_uart *hu)
{
        struct ath_struct *ath = hu->priv;

        BT_DBG("hu %p", hu);

        skb_queue_purge(&ath->txq);

        return 0;
}

/* Close protocol */
static int ath_close(struct hci_uart *hu)
{
        struct ath_struct *ath = hu->priv;

        BT_DBG("hu %p", hu);

        skb_queue_purge(&ath->txq);

        cancel_work_sync(&ath->ctxtsw);

        hu->priv = NULL;
        kfree(ath);

        return 0;
}

#define HCI_OP_ATH_SLEEP 0xFC04

/* Enqueue frame for transmittion */
static int ath_enqueue(struct hci_uart *hu, struct sk_buff *skb)
{
        struct ath_struct *ath = hu->priv;

        if (bt_cb(skb)->pkt_type == HCI_SCODATA_PKT) {
                kfree_skb(skb);
                return 0;
        }

        /*
         * Update power management enable flag with parameters of
         * HCI sleep enable vendor specific HCI command.
         */
        if (bt_cb(skb)->pkt_type == HCI_COMMAND_PKT) {
                struct hci_command_hdr *hdr = (void *)skb->data;

                if (__le16_to_cpu(hdr->opcode) == HCI_OP_ATH_SLEEP)
                        ath->cur_sleep = skb->data[HCI_COMMAND_HDR_SIZE];
        }

        BT_DBG("hu %p skb %p", hu, skb);

        /* Prepend skb with frame type */
        memcpy(skb_push(skb, 1), &bt_cb(skb)->pkt_type, 1);

        skb_queue_tail(&ath->txq, skb);
        set_bit(HCI_UART_SENDING, &hu->tx_state);

        schedule_work(&ath->ctxtsw);

        return 0;
}

static struct sk_buff *ath_dequeue(struct hci_uart *hu)
{
        struct ath_struct *ath = hu->priv;

        return skb_dequeue(&ath->txq);
}

/* Recv data */
static int ath_recv(struct hci_uart *hu, void *data, int count)
{
        int ret;

        ret = hci_recv_stream_fragment(hu->hdev, data, count);
        if (ret < 0) {
                BT_ERR("Frame Reassembly Failed");
                return ret;
        }

        return count;
}

static struct hci_uart_proto athp = {
        .id = HCI_UART_ATH3K,
        .open = ath_open,
        .close = ath_close,
        .recv = ath_recv,
        .enqueue = ath_enqueue,
        .dequeue = ath_dequeue,
        .flush = ath_flush,
};

int __init ath_init(void)
{
        int err = hci_uart_register_proto(&athp);

        if (!err)
                BT_INFO("HCIATH3K protocol initialized");
        else
                BT_ERR("HCIATH3K protocol registration failed");

        return err;
}

int __exit ath_deinit(void)
{
        return hci_uart_unregister_proto(&athp);
}