/*
 *
 *  Driver for Bluetooth PCMCIA cards with HCI UART interface
 *
 *  Copyright (C) 2001-2002  Marcel Holtmann <marcel@holtmann.org>
 *
 *
 *  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;
 *
 *  Software distributed under the License is distributed on an "AS
 *  IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 *  implied. See the License for the specific language governing
 *  rights and limitations under the License.
 *
 *  The initial developer of the original code is David A. Hinds
 *  <dahinds@users.sourceforge.net>.  Portions created by David A. Hinds
 *  are Copyright (C) 1999 David A. Hinds.  All Rights Reserved.
 *
 */

#include <linux/module.h>

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/ioport.h>
#include <linux/spinlock.h>
#include <linux/moduleparam.h>

#include <linux/skbuff.h>
#include <linux/string.h>
#include <linux/serial.h>
#include <linux/serial_reg.h>
#include <linux/bitops.h>
#include <linux/io.h>

#include <pcmcia/cistpl.h>
#include <pcmcia/ciscode.h>
#include <pcmcia/ds.h>
#include <pcmcia/cisreg.h>

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



/* ======================== Module parameters ======================== */


MODULE_AUTHOR("Marcel Holtmann <marcel@holtmann.org>");
MODULE_DESCRIPTION("Bluetooth driver for Bluetooth PCMCIA cards with HCI UART interface");
MODULE_LICENSE("GPL");



/* ======================== Local structures ======================== */


struct btuart_info {
        struct pcmcia_device *p_dev;

        struct hci_dev *hdev;

        spinlock_t lock;        /* For serializing operations */

        struct sk_buff_head txq;
        unsigned long tx_state;

        unsigned long rx_state;
        unsigned long rx_count;
        struct sk_buff *rx_skb;
};


static int btuart_config(struct pcmcia_device *link);
static void btuart_release(struct pcmcia_device *link);

static void btuart_detach(struct pcmcia_device *p_dev);


/* Maximum baud rate */
#define SPEED_MAX  115200

/* Default baud rate: 57600, 115200, 230400 or 460800 */
#define DEFAULT_BAUD_RATE  115200


/* Transmit states  */
#define XMIT_SENDING    1
#define XMIT_WAKEUP     2
#define XMIT_WAITING    8

/* Receiver states */
#define RECV_WAIT_PACKET_TYPE   0
#define RECV_WAIT_EVENT_HEADER  1
#define RECV_WAIT_ACL_HEADER    2
#define RECV_WAIT_SCO_HEADER    3
#define RECV_WAIT_DATA          4



/* ======================== Interrupt handling ======================== */


static int btuart_write(unsigned int iobase, int fifo_size, __u8 *buf, int len)
{
        int actual = 0;

        /* Tx FIFO should be empty */
        if (!(inb(iobase + UART_LSR) & UART_LSR_THRE))
                return 0;

        /* Fill FIFO with current frame */
        while ((fifo_size-- > 0) && (actual < len)) {
                /* Transmit next byte */
                outb(buf[actual], iobase + UART_TX);
                actual++;
        }

        return actual;
}


static void btuart_write_wakeup(struct btuart_info *info)
{
        if (!info) {
                BT_ERR("Unknown device");
                return;
        }

        if (test_and_set_bit(XMIT_SENDING, &(info->tx_state))) {
                set_bit(XMIT_WAKEUP, &(info->tx_state));
                return;
        }

        do {
                unsigned int iobase = info->p_dev->resource[0]->start;
                register struct sk_buff *skb;
                int len;

                clear_bit(XMIT_WAKEUP, &(info->tx_state));

                if (!pcmcia_dev_present(info->p_dev))
                        return;

                skb = skb_dequeue(&(info->txq));
                if (!skb)
                        break;

                /* Send frame */
                len = btuart_write(iobase, 16, skb->data, skb->len);
                set_bit(XMIT_WAKEUP, &(info->tx_state));

                if (len == skb->len) {
                        kfree_skb(skb);
                } else {
                        skb_pull(skb, len);
                        skb_queue_head(&(info->txq), skb);
                }

                info->hdev->stat.byte_tx += len;

        } while (test_bit(XMIT_WAKEUP, &(info->tx_state)));

        clear_bit(XMIT_SENDING, &(info->tx_state));
}


static void btuart_receive(struct btuart_info *info)
{
        unsigned int iobase;
        int boguscount = 0;

        if (!info) {
                BT_ERR("Unknown device");
                return;
        }

        iobase = info->p_dev->resource[0]->start;

        do {
                info->hdev->stat.byte_rx++;

                /* Allocate packet */
                if (!info->rx_skb) {
                        info->rx_state = RECV_WAIT_PACKET_TYPE;
                        info->rx_count = 0;
                        info->rx_skb = bt_skb_alloc(HCI_MAX_FRAME_SIZE, GFP_ATOMIC);
                        if (!info->rx_skb) {
                                BT_ERR("Can't allocate mem for new packet");
                                return;
                        }
                }

                if (info->rx_state == RECV_WAIT_PACKET_TYPE) {

                        hci_skb_pkt_type(info->rx_skb) = inb(iobase + UART_RX);

                        switch (hci_skb_pkt_type(info->rx_skb)) {

                        case HCI_EVENT_PKT:
                                info->rx_state = RECV_WAIT_EVENT_HEADER;
                                info->rx_count = HCI_EVENT_HDR_SIZE;
                                break;

                        case HCI_ACLDATA_PKT:
                                info->rx_state = RECV_WAIT_ACL_HEADER;
                                info->rx_count = HCI_ACL_HDR_SIZE;
                                break;

                        case HCI_SCODATA_PKT:
                                info->rx_state = RECV_WAIT_SCO_HEADER;
                                info->rx_count = HCI_SCO_HDR_SIZE;
                                break;

                        default:
                                /* Unknown packet */
                                BT_ERR("Unknown HCI packet with type 0x%02x received",
                                       hci_skb_pkt_type(info->rx_skb));
                                info->hdev->stat.err_rx++;

                                kfree_skb(info->rx_skb);
                                info->rx_skb = NULL;
                                break;

                        }

                } else {

                        *skb_put(info->rx_skb, 1) = inb(iobase + UART_RX);
                        info->rx_count--;

                        if (info->rx_count == 0) {

                                int dlen;
                                struct hci_event_hdr *eh;
                                struct hci_acl_hdr *ah;
                                struct hci_sco_hdr *sh;


                                switch (info->rx_state) {

                                case RECV_WAIT_EVENT_HEADER:
                                        eh = hci_event_hdr(info->rx_skb);
                                        info->rx_state = RECV_WAIT_DATA;
                                        info->rx_count = eh->plen;
                                        break;

                                case RECV_WAIT_ACL_HEADER:
                                        ah = hci_acl_hdr(info->rx_skb);
                                        dlen = __le16_to_cpu(ah->dlen);
                                        info->rx_state = RECV_WAIT_DATA;
                                        info->rx_count = dlen;
                                        break;

                                case RECV_WAIT_SCO_HEADER:
                                        sh = hci_sco_hdr(info->rx_skb);
                                        info->rx_state = RECV_WAIT_DATA;
                                        info->rx_count = sh->dlen;
                                        break;

                                case RECV_WAIT_DATA:
                                        hci_recv_frame(info->hdev, info->rx_skb);
                                        info->rx_skb = NULL;
                                        break;

                                }

                        }

                }

                /* Make sure we don't stay here too long */
                if (boguscount++ > 16)
                        break;

        } while (inb(iobase + UART_LSR) & UART_LSR_DR);
}


static irqreturn_t btuart_interrupt(int irq, void *dev_inst)
{
        struct btuart_info *info = dev_inst;
        unsigned int iobase;
        int boguscount = 0;
        int iir, lsr;
        irqreturn_t r = IRQ_NONE;

        if (!info || !info->hdev)
                /* our irq handler is shared */
                return IRQ_NONE;

        iobase = info->p_dev->resource[0]->start;

        spin_lock(&(info->lock));

        iir = inb(iobase + UART_IIR) & UART_IIR_ID;
        while (iir) {
                r = IRQ_HANDLED;

                /* Clear interrupt */
                lsr = inb(iobase + UART_LSR);

                switch (iir) {
                case UART_IIR_RLSI:
                        BT_ERR("RLSI");
                        break;
                case UART_IIR_RDI:
                        /* Receive interrupt */
                        btuart_receive(info);
                        break;
                case UART_IIR_THRI:
                        if (lsr & UART_LSR_THRE) {
                                /* Transmitter ready for data */
                                btuart_write_wakeup(info);
                        }
                        break;
                default:
                        BT_ERR("Unhandled IIR=%#x", iir);
                        break;
                }

                /* Make sure we don't stay here too long */
                if (boguscount++ > 100)
                        break;

                iir = inb(iobase + UART_IIR) & UART_IIR_ID;

        }

        spin_unlock(&(info->lock));

        return r;
}


static void btuart_change_speed(struct btuart_info *info,
                                unsigned int speed)
{
        unsigned long flags;
        unsigned int iobase;
        int fcr;                /* FIFO control reg */
        int lcr;                /* Line control reg */
        int divisor;

        if (!info) {
                BT_ERR("Unknown device");
                return;
        }

        iobase = info->p_dev->resource[0]->start;

        spin_lock_irqsave(&(info->lock), flags);

        /* Turn off interrupts */
        outb(0, iobase + UART_IER);

        divisor = SPEED_MAX / speed;

        fcr = UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT;

        /* 
         * Use trigger level 1 to avoid 3 ms. timeout delay at 9600 bps, and
         * almost 1,7 ms at 19200 bps. At speeds above that we can just forget
         * about this timeout since it will always be fast enough. 
         */

        if (speed < 38400)
                fcr |= UART_FCR_TRIGGER_1;
        else
                fcr |= UART_FCR_TRIGGER_14;

        /* Bluetooth cards use 8N1 */
        lcr = UART_LCR_WLEN8;

        outb(UART_LCR_DLAB | lcr, iobase + UART_LCR);   /* Set DLAB */
        outb(divisor & 0xff, iobase + UART_DLL);        /* Set speed */
        outb(divisor >> 8, iobase + UART_DLM);
        outb(lcr, iobase + UART_LCR);   /* Set 8N1  */
        outb(fcr, iobase + UART_FCR);   /* Enable FIFO's */

        /* Turn on interrupts */
        outb(UART_IER_RLSI | UART_IER_RDI | UART_IER_THRI, iobase + UART_IER);

        spin_unlock_irqrestore(&(info->lock), flags);
}



/* ======================== HCI interface ======================== */


static int btuart_hci_flush(struct hci_dev *hdev)
{
        struct btuart_info *info = hci_get_drvdata(hdev);

        /* Drop TX queue */
        skb_queue_purge(&(info->txq));

        return 0;
}


static int btuart_hci_open(struct hci_dev *hdev)
{
        return 0;
}


static int btuart_hci_close(struct hci_dev *hdev)
{
        btuart_hci_flush(hdev);

        return 0;
}


static int btuart_hci_send_frame(struct hci_dev *hdev, struct sk_buff *skb)
{
        struct btuart_info *info = hci_get_drvdata(hdev);

        switch (hci_skb_pkt_type(skb)) {
        case HCI_COMMAND_PKT:
                hdev->stat.cmd_tx++;
                break;
        case HCI_ACLDATA_PKT:
                hdev->stat.acl_tx++;
                break;
        case HCI_SCODATA_PKT:
                hdev->stat.sco_tx++;
                break;
        }

        /* Prepend skb with frame type */
        memcpy(skb_push(skb, 1), &hci_skb_pkt_type(skb), 1);
        skb_queue_tail(&(info->txq), skb);

        btuart_write_wakeup(info);

        return 0;
}



/* ======================== Card services HCI interaction ======================== */


static int btuart_open(struct btuart_info *info)
{
        unsigned long flags;
        unsigned int iobase = info->p_dev->resource[0]->start;
        struct hci_dev *hdev;

        spin_lock_init(&(info->lock));

        skb_queue_head_init(&(info->txq));

        info->rx_state = RECV_WAIT_PACKET_TYPE;
        info->rx_count = 0;
        info->rx_skb = NULL;

        /* Initialize HCI device */
        hdev = hci_alloc_dev();
        if (!hdev) {
                BT_ERR("Can't allocate HCI device");
                return -ENOMEM;
        }

        info->hdev = hdev;

        hdev->bus = HCI_PCCARD;
        hci_set_drvdata(hdev, info);
        SET_HCIDEV_DEV(hdev, &info->p_dev->dev);

        hdev->open  = btuart_hci_open;
        hdev->close = btuart_hci_close;
        hdev->flush = btuart_hci_flush;
        hdev->send  = btuart_hci_send_frame;

        spin_lock_irqsave(&(info->lock), flags);

        /* Reset UART */
        outb(0, iobase + UART_MCR);

        /* Turn off interrupts */
        outb(0, iobase + UART_IER);

        /* Initialize UART */
        outb(UART_LCR_WLEN8, iobase + UART_LCR);        /* Reset DLAB */
        outb((UART_MCR_DTR | UART_MCR_RTS | UART_MCR_OUT2), iobase + UART_MCR);

        /* Turn on interrupts */
        // outb(UART_IER_RLSI | UART_IER_RDI | UART_IER_THRI, iobase + UART_IER);

        spin_unlock_irqrestore(&(info->lock), flags);

        btuart_change_speed(info, DEFAULT_BAUD_RATE);

        /* Timeout before it is safe to send the first HCI packet */
        msleep(1000);

        /* Register HCI device */
        if (hci_register_dev(hdev) < 0) {
                BT_ERR("Can't register HCI device");
                info->hdev = NULL;
                hci_free_dev(hdev);
                return -ENODEV;
        }

        return 0;
}


static int btuart_close(struct btuart_info *info)
{
        unsigned long flags;
        unsigned int iobase = info->p_dev->resource[0]->start;
        struct hci_dev *hdev = info->hdev;

        if (!hdev)
                return -ENODEV;

        btuart_hci_close(hdev);

        spin_lock_irqsave(&(info->lock), flags);

        /* Reset UART */
        outb(0, iobase + UART_MCR);

        /* Turn off interrupts */
        outb(0, iobase + UART_IER);

        spin_unlock_irqrestore(&(info->lock), flags);

        hci_unregister_dev(hdev);
        hci_free_dev(hdev);

        return 0;
}

static int btuart_probe(struct pcmcia_device *link)
{
        struct btuart_info *info;

        /* Create new info device */
        info = devm_kzalloc(&link->dev, sizeof(*info), GFP_KERNEL);
        if (!info)
                return -ENOMEM;

        info->p_dev = link;
        link->priv = info;

        link->config_flags |= CONF_ENABLE_IRQ | CONF_AUTO_SET_VPP |
                CONF_AUTO_SET_IO;

        return btuart_config(link);
}


static void btuart_detach(struct pcmcia_device *link)
{
        btuart_release(link);
}

static int btuart_check_config(struct pcmcia_device *p_dev, void *priv_data)
{
        int *try = priv_data;

        if (!try)
                p_dev->io_lines = 16;

        if ((p_dev->resource[0]->end != 8) || (p_dev->resource[0]->start == 0))
                return -EINVAL;

        p_dev->resource[0]->end = 8;
        p_dev->resource[0]->flags &= ~IO_DATA_PATH_WIDTH;
        p_dev->resource[0]->flags |= IO_DATA_PATH_WIDTH_8;

        return pcmcia_request_io(p_dev);
}

static int btuart_check_config_notpicky(struct pcmcia_device *p_dev,
                                        void *priv_data)
{
        static unsigned int base[5] = { 0x3f8, 0x2f8, 0x3e8, 0x2e8, 0x0 };
        int j;

        if (p_dev->io_lines > 3)
                return -ENODEV;

        p_dev->resource[0]->flags &= ~IO_DATA_PATH_WIDTH;
        p_dev->resource[0]->flags |= IO_DATA_PATH_WIDTH_8;
        p_dev->resource[0]->end = 8;

        for (j = 0; j < 5; j++) {
                p_dev->resource[0]->start = base[j];
                p_dev->io_lines = base[j] ? 16 : 3;
                if (!pcmcia_request_io(p_dev))
                        return 0;
        }
        return -ENODEV;
}

static int btuart_config(struct pcmcia_device *link)
{
        struct btuart_info *info = link->priv;
        int i;
        int try;

        /* First pass: look for a config entry that looks normal.
           Two tries: without IO aliases, then with aliases */
        for (try = 0; try < 2; try++)
                if (!pcmcia_loop_config(link, btuart_check_config, &try))
                        goto found_port;

        /* Second pass: try to find an entry that isn't picky about
           its base address, then try to grab any standard serial port
           address, and finally try to get any free port. */
        if (!pcmcia_loop_config(link, btuart_check_config_notpicky, NULL))
                goto found_port;

        BT_ERR("No usable port range found");
        goto failed;

found_port:
        i = pcmcia_request_irq(link, btuart_interrupt);
        if (i != 0)
                goto failed;

        i = pcmcia_enable_device(link);
        if (i != 0)
                goto failed;

        if (btuart_open(info) != 0)
                goto failed;

        return 0;

failed:
        btuart_release(link);
        return -ENODEV;
}


static void btuart_release(struct pcmcia_device *link)
{
        struct btuart_info *info = link->priv;

        btuart_close(info);

        pcmcia_disable_device(link);
}

static const struct pcmcia_device_id btuart_ids[] = {
        /* don't use this driver. Use serial_cs + hci_uart instead */
        PCMCIA_DEVICE_NULL
};
MODULE_DEVICE_TABLE(pcmcia, btuart_ids);

static struct pcmcia_driver btuart_driver = {
        .owner          = THIS_MODULE,
        .name           = "btuart_cs",
        .probe          = btuart_probe,
        .remove         = btuart_detach,
        .id_table       = btuart_ids,
};
module_pcmcia_driver(btuart_driver);