btwilink.c

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/*
 *  Texas Instrument's Bluetooth Driver For Shared Transport.
 *
 *  Bluetooth Driver acts as interface between HCI core and
 *  TI Shared Transport Layer.
 *
 *  Copyright (C) 2009-2010 Texas Instruments
 *  Author: Raja Mani <[email protected]>
 *  Pavan Savoy <[email protected]>
 *
 *  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.
 *
 *  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
 *
 */
#define DEBUG
#include <linux/platform_device.h>
#include <net/bluetooth/bluetooth.h>
#include <net/bluetooth/hci_core.h>
#include <net/bluetooth/hci.h>

#include <linux/ti_wilink_st.h>
#include <linux/module.h>

/* Bluetooth Driver Version */
#define VERSION               "1.0"
#define MAX_BT_CHNL_IDS     3

/* Number of seconds to wait for registration completion
 * when ST returns PENDING status.
 */
#define BT_REGISTER_TIMEOUT   6000  /* 6 sec */

struct ti_st {
    struct hci_dev *hdev;
    char reg_status;
    long (*st_write) (struct sk_buff *);
    struct completion wait_reg_completion;
};

/* Increments HCI counters based on pocket ID (cmd,acl,sco) */
static inline void ti_st_tx_complete(struct ti_st *hst, int pkt_type)
{
    struct hci_dev *hdev = hst->hdev;

    /* Update HCI stat counters */
    switch (pkt_type) {
    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;
    }
}

/* ------- Interfaces to Shared Transport ------ */

/* Called by ST layer to indicate protocol registration completion
 * status.ti_st_open() function will wait for signal from this
 * API when st_register() function returns ST_PENDING.
 */
static void st_reg_completion_cb(void *priv_data, char data)
{
    struct ti_st *lhst = priv_data;

    /* Save registration status for use in ti_st_open() */
    lhst->reg_status = data;
    /* complete the wait in ti_st_open() */
    complete(&lhst->wait_reg_completion);
}

/* Called by Shared Transport layer when receive data is
 * available */
static long st_receive(void *priv_data, struct sk_buff *skb)
{
    struct ti_st *lhst = priv_data;
    int err;

    if (!skb)
        return -EFAULT;

    if (!lhst) {
        kfree_skb(skb);
        return -EFAULT;
    }

    skb->dev = (void *) lhst->hdev;

    /* Forward skb to HCI core layer */
    err = hci_recv_frame(skb);
    if (err < 0) {
        BT_ERR("Unable to push skb to HCI core(%d)", err);
        return err;
    }

    lhst->hdev->stat.byte_rx += skb->len;

    return 0;
}

/* ------- Interfaces to HCI layer ------ */
/* protocol structure registered with shared transport */
static struct st_proto_s ti_st_proto[MAX_BT_CHNL_IDS] = {
    {
        .chnl_id = HCI_EVENT_PKT, /* HCI Events */
        .hdr_len = sizeof(struct hci_event_hdr),
        .offset_len_in_hdr = offsetof(struct hci_event_hdr, plen),
        .len_size = 1, /* sizeof(plen) in struct hci_event_hdr */
        .reserve = 8,
    },
    {
        .chnl_id = HCI_ACLDATA_PKT, /* ACL */
        .hdr_len = sizeof(struct hci_acl_hdr),
        .offset_len_in_hdr = offsetof(struct hci_acl_hdr, dlen),
        .len_size = 2,  /* sizeof(dlen) in struct hci_acl_hdr */
        .reserve = 8,
    },
    {
        .chnl_id = HCI_SCODATA_PKT, /* SCO */
        .hdr_len = sizeof(struct hci_sco_hdr),
        .offset_len_in_hdr = offsetof(struct hci_sco_hdr, dlen),
        .len_size = 1, /* sizeof(dlen) in struct hci_sco_hdr */
        .reserve = 8,
    },
};

/* Called from HCI core to initialize the device */
static int ti_st_open(struct hci_dev *hdev)
{
    unsigned long timeleft;
    struct ti_st *hst;
    int err, i;

    BT_DBG("%s %p", hdev->name, hdev);

    if (test_and_set_bit(HCI_RUNNING, &hdev->flags))
        return -EBUSY;

    /* provide contexts for callbacks from ST */
    hst = hci_get_drvdata(hdev);

    for (i = 0; i < MAX_BT_CHNL_IDS; i++) {
        ti_st_proto[i].priv_data = hst;
        ti_st_proto[i].max_frame_size = HCI_MAX_FRAME_SIZE;
        ti_st_proto[i].recv = st_receive;
        ti_st_proto[i].reg_complete_cb = st_reg_completion_cb;

        /* Prepare wait-for-completion handler */
        init_completion(&hst->wait_reg_completion);
        /* Reset ST registration callback status flag,
         * this value will be updated in
         * st_reg_completion_cb()
         * function whenever it called from ST driver.
         */
        hst->reg_status = -EINPROGRESS;

        err = st_register(&ti_st_proto[i]);
        if (!err)
            goto done;

        if (err != -EINPROGRESS) {
            clear_bit(HCI_RUNNING, &hdev->flags);
            BT_ERR("st_register failed %d", err);
            return err;
        }

        /* ST is busy with either protocol
         * registration or firmware download.
         */
        BT_DBG("waiting for registration "
                "completion signal from ST");
        timeleft = wait_for_completion_timeout
            (&hst->wait_reg_completion,
             msecs_to_jiffies(BT_REGISTER_TIMEOUT));
        if (!timeleft) {
            clear_bit(HCI_RUNNING, &hdev->flags);
            BT_ERR("Timeout(%d sec),didn't get reg "
                    "completion signal from ST",
                    BT_REGISTER_TIMEOUT / 1000);
            return -ETIMEDOUT;
        }

        /* Is ST registration callback
         * called with ERROR status? */
        if (hst->reg_status != 0) {
            clear_bit(HCI_RUNNING, &hdev->flags);
            BT_ERR("ST registration completed with invalid "
                    "status %d", hst->reg_status);
            return -EAGAIN;
        }

done:
        hst->st_write = ti_st_proto[i].write;
        if (!hst->st_write) {
            BT_ERR("undefined ST write function");
            clear_bit(HCI_RUNNING, &hdev->flags);
            for (i = 0; i < MAX_BT_CHNL_IDS; i++) {
                /* Undo registration with ST */
                err = st_unregister(&ti_st_proto[i]);
                if (err)
                    BT_ERR("st_unregister() failed with "
                            "error %d", err);
                hst->st_write = NULL;
            }
            return -EIO;
        }
    }
    return 0;
}

/* Close device */
static int ti_st_close(struct hci_dev *hdev)
{
    int err, i;
    struct ti_st *hst = hci_get_drvdata(hdev);

    if (!test_and_clear_bit(HCI_RUNNING, &hdev->flags))
        return 0;

    for (i = MAX_BT_CHNL_IDS-1; i >= 0; i--) {
        err = st_unregister(&ti_st_proto[i]);
        if (err)
            BT_ERR("st_unregister(%d) failed with error %d",
                    ti_st_proto[i].chnl_id, err);
    }

    hst->st_write = NULL;

    return err;
}

static int ti_st_send_frame(struct sk_buff *skb)
{
    struct hci_dev *hdev;
    struct ti_st *hst;
    long len;

    hdev = (struct hci_dev *)skb->dev;

    if (!test_bit(HCI_RUNNING, &hdev->flags))
        return -EBUSY;

    hst = hci_get_drvdata(hdev);

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

    BT_DBG("%s: type %d len %d", hdev->name, bt_cb(skb)->pkt_type,
            skb->len);

    /* Insert skb to shared transport layer's transmit queue.
     * Freeing skb memory is taken care in shared transport layer,
     * so don't free skb memory here.
     */
    len = hst->st_write(skb);
    if (len < 0) {
        kfree_skb(skb);
        BT_ERR("ST write failed (%ld)", len);
        /* Try Again, would only fail if UART has gone bad */
        return -EAGAIN;
    }

    /* ST accepted our skb. So, Go ahead and do rest */
    hdev->stat.byte_tx += len;
    ti_st_tx_complete(hst, bt_cb(skb)->pkt_type);

    return 0;
}

static int bt_ti_probe(struct platform_device *pdev)
{
    static struct ti_st *hst;
    struct hci_dev *hdev;
    int err;

    hst = devm_kzalloc(&pdev->dev, sizeof(struct ti_st), GFP_KERNEL);
    if (!hst)
        return -ENOMEM;

    /* Expose "hciX" device to user space */
    hdev = hci_alloc_dev();
    if (!hdev)
        return -ENOMEM;

    BT_DBG("hdev %p", hdev);

    hst->hdev = hdev;
    hdev->bus = HCI_UART;
    hci_set_drvdata(hdev, hst);
    hdev->open = ti_st_open;
    hdev->close = ti_st_close;
    hdev->flush = NULL;
    hdev->send = ti_st_send_frame;

    err = hci_register_dev(hdev);
    if (err < 0) {
        BT_ERR("Can't register HCI device error %d", err);
        hci_free_dev(hdev);
        return err;
    }

    BT_DBG("HCI device registered (hdev %p)", hdev);

    dev_set_drvdata(&pdev->dev, hst);
    return err;
}

static int bt_ti_remove(struct platform_device *pdev)
{
    struct hci_dev *hdev;
    struct ti_st *hst = dev_get_drvdata(&pdev->dev);

    if (!hst)
        return -EFAULT;

    BT_DBG("%s", hst->hdev->name);

    hdev = hst->hdev;
    ti_st_close(hdev);
    hci_unregister_dev(hdev);

    hci_free_dev(hdev);

    dev_set_drvdata(&pdev->dev, NULL);
    return 0;
}

static struct platform_driver btwilink_driver = {
    .probe = bt_ti_probe,
    .remove = bt_ti_remove,
    .driver = {
        .name = "btwilink",
        .owner = THIS_MODULE,
    },
};

module_platform_driver(btwilink_driver);

/* ------ Module Info ------ */

MODULE_AUTHOR("Raja Mani <[email protected]>");
MODULE_DESCRIPTION("Bluetooth Driver for TI Shared Transport" VERSION);
MODULE_VERSION(VERSION);
MODULE_LICENSE("GPL");