/*
 *  Texas Instrument's NFC Driver For Shared Transport.
 *
 *  NFC Driver acts as interface between NCI core and
 *  TI Shared Transport Layer.
 *
 *  Copyright (C) 2011 Texas Instruments, Inc.
 *
 *  Written by Ilan Elias <ilane@ti.com>
 *
 *  Acknowledgements:
 *  This file is based on btwilink.c, which was written
 *  by Raja Mani and Pavan Savoy.
 *
 *  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
 *
 */
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/nfc.h>
#include <net/nfc/nci.h>
#include <net/nfc/nci_core.h>
#include <linux/ti_wilink_st.h>

#define NFCWILINK_CHNL                  12
#define NFCWILINK_OPCODE                7
#define NFCWILINK_MAX_FRAME_SIZE        300
#define NFCWILINK_HDR_LEN               4
#define NFCWILINK_OFFSET_LEN_IN_HDR     1
#define NFCWILINK_LEN_SIZE              2
#define NFCWILINK_REGISTER_TIMEOUT      8000    /* 8 sec */

struct nfcwilink_hdr {
        u8 chnl;
        u8 opcode;
        u16 len;
} __packed;

struct nfcwilink {
        struct platform_device          *pdev;
        struct nci_dev                  *ndev;
        unsigned long                   flags;

        char                            st_register_cb_status;
        long                            (*st_write) (struct sk_buff *);
        struct completion               st_register_completed;
};

/* NFCWILINK driver flags */
enum {
        NFCWILINK_RUNNING,
};

/* Called by ST when registration is complete */
static void nfcwilink_register_complete(void *priv_data, char data)
{
        struct nfcwilink *drv = priv_data;

        nfc_dev_dbg(&drv->pdev->dev, "register_complete entry");

        /* store ST registration status */
        drv->st_register_cb_status = data;

        /* complete the wait in nfc_st_open() */
        complete(&drv->st_register_completed);
}

/* Called by ST when receive data is available */
static long nfcwilink_receive(void *priv_data, struct sk_buff *skb)
{
        struct nfcwilink *drv = priv_data;
        int rc;

        nfc_dev_dbg(&drv->pdev->dev, "receive entry, len %d", skb->len);

        if (!skb)
                return -EFAULT;

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

        /* strip the ST header
        (apart for the chnl byte, which is not received in the hdr) */
        skb_pull(skb, (NFCWILINK_HDR_LEN-1));

        skb->dev = (void *) drv->ndev;

        /* Forward skb to NCI core layer */
        rc = nci_recv_frame(skb);
        if (rc < 0) {
                nfc_dev_err(&drv->pdev->dev, "nci_recv_frame failed %d", rc);
                return rc;
        }

        return 0;
}

/* protocol structure registered with ST */
static struct st_proto_s nfcwilink_proto = {
        .chnl_id = NFCWILINK_CHNL,
        .max_frame_size = NFCWILINK_MAX_FRAME_SIZE,
        .hdr_len = (NFCWILINK_HDR_LEN-1),       /* not including chnl byte */
        .offset_len_in_hdr = NFCWILINK_OFFSET_LEN_IN_HDR,
        .len_size = NFCWILINK_LEN_SIZE,
        .reserve = 0,
        .recv = nfcwilink_receive,
        .reg_complete_cb = nfcwilink_register_complete,
        .write = NULL,
};

static int nfcwilink_open(struct nci_dev *ndev)
{
        struct nfcwilink *drv = nci_get_drvdata(ndev);
        unsigned long comp_ret;
        int rc;

        nfc_dev_dbg(&drv->pdev->dev, "open entry");

        if (test_and_set_bit(NFCWILINK_RUNNING, &drv->flags)) {
                rc = -EBUSY;
                goto exit;
        }

        nfcwilink_proto.priv_data = drv;

        init_completion(&drv->st_register_completed);
        drv->st_register_cb_status = -EINPROGRESS;

        rc = st_register(&nfcwilink_proto);
        if (rc < 0) {
                if (rc == -EINPROGRESS) {
                        comp_ret = wait_for_completion_timeout(
                        &drv->st_register_completed,
                        msecs_to_jiffies(NFCWILINK_REGISTER_TIMEOUT));

                        nfc_dev_dbg(&drv->pdev->dev,
                        "wait_for_completion_timeout returned %ld",
                        comp_ret);

                        if (comp_ret == 0) {
                                /* timeout */
                                rc = -ETIMEDOUT;
                                goto clear_exit;
                        } else if (drv->st_register_cb_status != 0) {
                                rc = drv->st_register_cb_status;
                                nfc_dev_err(&drv->pdev->dev,
                                "st_register_cb failed %d", rc);
                                goto clear_exit;
                        }
                } else {
                        nfc_dev_err(&drv->pdev->dev,
                                "st_register failed %d", rc);
                        goto clear_exit;
                }
        }

        /* st_register MUST fill the write callback */
        BUG_ON(nfcwilink_proto.write == NULL);
        drv->st_write = nfcwilink_proto.write;

        goto exit;

clear_exit:
        clear_bit(NFCWILINK_RUNNING, &drv->flags);

exit:
        return rc;
}

static int nfcwilink_close(struct nci_dev *ndev)
{
        struct nfcwilink *drv = nci_get_drvdata(ndev);
        int rc;

        nfc_dev_dbg(&drv->pdev->dev, "close entry");

        if (!test_and_clear_bit(NFCWILINK_RUNNING, &drv->flags))
                return 0;

        rc = st_unregister(&nfcwilink_proto);
        if (rc)
                nfc_dev_err(&drv->pdev->dev, "st_unregister failed %d", rc);

        drv->st_write = NULL;

        return rc;
}

static int nfcwilink_send(struct sk_buff *skb)
{
        struct nci_dev *ndev = (struct nci_dev *)skb->dev;
        struct nfcwilink *drv = nci_get_drvdata(ndev);
        struct nfcwilink_hdr hdr = {NFCWILINK_CHNL, NFCWILINK_OPCODE, 0x0000};
        long len;

        nfc_dev_dbg(&drv->pdev->dev, "send entry, len %d", skb->len);

        if (!test_bit(NFCWILINK_RUNNING, &drv->flags))
                return -EBUSY;

        /* add the ST hdr to the start of the buffer */
        hdr.len = skb->len;
        memcpy(skb_push(skb, NFCWILINK_HDR_LEN), &hdr, NFCWILINK_HDR_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 = drv->st_write(skb);
        if (len < 0) {
                kfree_skb(skb);
                nfc_dev_err(&drv->pdev->dev, "st_write failed %ld", len);
                return -EFAULT;
        }

        return 0;
}

static struct nci_ops nfcwilink_ops = {
        .open = nfcwilink_open,
        .close = nfcwilink_close,
        .send = nfcwilink_send,
};

static int nfcwilink_probe(struct platform_device *pdev)
{
        static struct nfcwilink *drv;
        int rc;
        u32 protocols;

        nfc_dev_dbg(&pdev->dev, "probe entry");

        drv = kzalloc(sizeof(struct nfcwilink), GFP_KERNEL);
        if (!drv) {
                rc = -ENOMEM;
                goto exit;
        }

        drv->pdev = pdev;

        protocols = NFC_PROTO_JEWEL_MASK
                        | NFC_PROTO_MIFARE_MASK | NFC_PROTO_FELICA_MASK
                        | NFC_PROTO_ISO14443_MASK
                        | NFC_PROTO_NFC_DEP_MASK;

        drv->ndev = nci_allocate_device(&nfcwilink_ops,
                                        protocols,
                                        NFCWILINK_HDR_LEN,
                                        0);
        if (!drv->ndev) {
                nfc_dev_err(&pdev->dev, "nci_allocate_device failed");
                rc = -ENOMEM;
                goto free_exit;
        }

        nci_set_parent_dev(drv->ndev, &pdev->dev);
        nci_set_drvdata(drv->ndev, drv);

        rc = nci_register_device(drv->ndev);
        if (rc < 0) {
                nfc_dev_err(&pdev->dev, "nci_register_device failed %d", rc);
                goto free_dev_exit;
        }

        dev_set_drvdata(&pdev->dev, drv);

        goto exit;

free_dev_exit:
        nci_free_device(drv->ndev);

free_exit:
        kfree(drv);

exit:
        return rc;
}

static int nfcwilink_remove(struct platform_device *pdev)
{
        struct nfcwilink *drv = dev_get_drvdata(&pdev->dev);
        struct nci_dev *ndev;

        nfc_dev_dbg(&pdev->dev, "remove entry");

        if (!drv)
                return -EFAULT;

        ndev = drv->ndev;

        nci_unregister_device(ndev);
        nci_free_device(ndev);

        kfree(drv);

        dev_set_drvdata(&pdev->dev, NULL);

        return 0;
}

static struct platform_driver nfcwilink_driver = {
        .probe = nfcwilink_probe,
        .remove = nfcwilink_remove,
        .driver = {
                .name = "nfcwilink",
                .owner = THIS_MODULE,
        },
};

/* ------- Module Init/Exit interfaces ------ */
static int __init nfcwilink_init(void)
{
        printk(KERN_INFO "NFC Driver for TI WiLink");

        return platform_driver_register(&nfcwilink_driver);
}

static void __exit nfcwilink_exit(void)
{
        platform_driver_unregister(&nfcwilink_driver);
}

module_init(nfcwilink_init);
module_exit(nfcwilink_exit);

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

MODULE_AUTHOR("Ilan Elias <ilane@ti.com>");
MODULE_DESCRIPTION("NFC Driver for TI Shared Transport");
MODULE_LICENSE("GPL");