/*
 *  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, see <http://www.gnu.org/licenses/>.
 *
 */
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/firmware.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 */
#define NFCWILINK_CMD_TIMEOUT           5000    /* 5 sec */

#define BTS_FILE_NAME_MAX_SIZE          40
#define BTS_FILE_HDR_MAGIC              0x42535442
#define BTS_FILE_CMD_MAX_LEN            0xff
#define BTS_FILE_ACTION_TYPE_SEND_CMD   1

#define NCI_VS_NFCC_INFO_CMD_GID        0x2f
#define NCI_VS_NFCC_INFO_CMD_OID        0x12
#define NCI_VS_NFCC_INFO_RSP_GID        0x4f
#define NCI_VS_NFCC_INFO_RSP_OID        0x12

struct nfcwilink_hdr {
        __u8 chnl;
        __u8 opcode;
        __le16 len;
} __packed;

struct nci_vs_nfcc_info_cmd {
        __u8 gid;
        __u8 oid;
        __u8 plen;
} __packed;

struct nci_vs_nfcc_info_rsp {
        __u8 gid;
        __u8 oid;
        __u8 plen;
        __u8 status;
        __u8 hw_id;
        __u8 sw_ver_x;
        __u8 sw_ver_z;
        __u8 patch_id;
} __packed;

struct bts_file_hdr {
        __le32 magic;
        __le32 ver;
        __u8 rfu[24];
        __u8 actions[0];
} __packed;

struct bts_file_action {
        __le16 type;
        __le16 len;
        __u8 data[0];
} __packed;

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

        int                             st_register_cb_status;
        long                            (*st_write) (struct sk_buff *);

        struct completion               completed;

        struct nci_vs_nfcc_info_rsp     nfcc_info;
};

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

static int nfcwilink_send(struct nci_dev *ndev, struct sk_buff *skb);

static inline struct sk_buff *nfcwilink_skb_alloc(unsigned int len, gfp_t how)
{
        struct sk_buff *skb;

        skb = alloc_skb(len + NFCWILINK_HDR_LEN, how);
        if (skb)
                skb_reserve(skb, NFCWILINK_HDR_LEN);

        return skb;
}

static void nfcwilink_fw_download_receive(struct nfcwilink *drv,
                                                struct sk_buff *skb)
{
        struct nci_vs_nfcc_info_rsp *rsp = (void *)skb->data;

        /* Detect NCI_VS_NFCC_INFO_RSP and store the result */
        if ((skb->len > 3) && (rsp->gid == NCI_VS_NFCC_INFO_RSP_GID) &&
                (rsp->oid == NCI_VS_NFCC_INFO_RSP_OID)) {
                memcpy(&drv->nfcc_info, rsp,
                        sizeof(struct nci_vs_nfcc_info_rsp));
        }

        kfree_skb(skb);

        complete(&drv->completed);
}

static int nfcwilink_get_bts_file_name(struct nfcwilink *drv, char *file_name)
{
        struct nci_vs_nfcc_info_cmd *cmd;
        struct sk_buff *skb;
        unsigned long comp_ret;
        int rc;

        skb = nfcwilink_skb_alloc(sizeof(struct nci_vs_nfcc_info_cmd),
                                        GFP_KERNEL);
        if (!skb) {
                nfc_err(&drv->pdev->dev,
                        "no memory for nci_vs_nfcc_info_cmd\n");
                return -ENOMEM;
        }

        cmd = (struct nci_vs_nfcc_info_cmd *)
                        skb_put(skb, sizeof(struct nci_vs_nfcc_info_cmd));
        cmd->gid = NCI_VS_NFCC_INFO_CMD_GID;
        cmd->oid = NCI_VS_NFCC_INFO_CMD_OID;
        cmd->plen = 0;

        drv->nfcc_info.plen = 0;

        rc = nfcwilink_send(drv->ndev, skb);
        if (rc)
                return rc;

        comp_ret = wait_for_completion_timeout(&drv->completed,
                                msecs_to_jiffies(NFCWILINK_CMD_TIMEOUT));
        dev_dbg(&drv->pdev->dev, "wait_for_completion_timeout returned %ld\n",
                comp_ret);
        if (comp_ret == 0) {
                nfc_err(&drv->pdev->dev,
                        "timeout on wait_for_completion_timeout\n");
                return -ETIMEDOUT;
        }

        dev_dbg(&drv->pdev->dev, "nci_vs_nfcc_info_rsp: plen %d, status %d\n",
                drv->nfcc_info.plen, drv->nfcc_info.status);

        if ((drv->nfcc_info.plen != 5) || (drv->nfcc_info.status != 0)) {
                nfc_err(&drv->pdev->dev, "invalid nci_vs_nfcc_info_rsp\n");
                return -EINVAL;
        }

        snprintf(file_name, BTS_FILE_NAME_MAX_SIZE,
                        "TINfcInit_%d.%d.%d.%d.bts",
                        drv->nfcc_info.hw_id,
                        drv->nfcc_info.sw_ver_x,
                        drv->nfcc_info.sw_ver_z,
                        drv->nfcc_info.patch_id);

        nfc_info(&drv->pdev->dev, "nfcwilink FW file name: %s\n", file_name);

        return 0;
}

static int nfcwilink_send_bts_cmd(struct nfcwilink *drv, __u8 *data, int len)
{
        struct nfcwilink_hdr *hdr = (struct nfcwilink_hdr *)data;
        struct sk_buff *skb;
        unsigned long comp_ret;
        int rc;

        /* verify valid cmd for the NFC channel */
        if ((len <= sizeof(struct nfcwilink_hdr)) ||
                (len > BTS_FILE_CMD_MAX_LEN) ||
                (hdr->chnl != NFCWILINK_CHNL) ||
                (hdr->opcode != NFCWILINK_OPCODE)) {
                nfc_err(&drv->pdev->dev,
                        "ignoring invalid bts cmd, len %d, chnl %d, opcode %d\n",
                        len, hdr->chnl, hdr->opcode);
                return 0;
        }

        /* remove the ST header */
        len -= sizeof(struct nfcwilink_hdr);
        data += sizeof(struct nfcwilink_hdr);

        skb = nfcwilink_skb_alloc(len, GFP_KERNEL);
        if (!skb) {
                nfc_err(&drv->pdev->dev, "no memory for bts cmd\n");
                return -ENOMEM;
        }

        memcpy(skb_put(skb, len), data, len);

        rc = nfcwilink_send(drv->ndev, skb);
        if (rc)
                return rc;

        comp_ret = wait_for_completion_timeout(&drv->completed,
                                msecs_to_jiffies(NFCWILINK_CMD_TIMEOUT));
        dev_dbg(&drv->pdev->dev, "wait_for_completion_timeout returned %ld\n",
                comp_ret);
        if (comp_ret == 0) {
                nfc_err(&drv->pdev->dev,
                        "timeout on wait_for_completion_timeout\n");
                return -ETIMEDOUT;
        }

        return 0;
}

static int nfcwilink_download_fw(struct nfcwilink *drv)
{
        unsigned char file_name[BTS_FILE_NAME_MAX_SIZE];
        const struct firmware *fw;
        __u16 action_type, action_len;
        __u8 *ptr;
        int len, rc;

        set_bit(NFCWILINK_FW_DOWNLOAD, &drv->flags);

        rc = nfcwilink_get_bts_file_name(drv, file_name);
        if (rc)
                goto exit;

        rc = request_firmware(&fw, file_name, &drv->pdev->dev);
        if (rc) {
                nfc_err(&drv->pdev->dev, "request_firmware failed %d\n", rc);

                /* if the file is not found, don't exit with failure */
                if (rc == -ENOENT)
                        rc = 0;

                goto exit;
        }

        len = fw->size;
        ptr = (__u8 *)fw->data;

        if ((len == 0) || (ptr == NULL)) {
                dev_dbg(&drv->pdev->dev,
                        "request_firmware returned size %d\n", len);
                goto release_fw;
        }

        if (__le32_to_cpu(((struct bts_file_hdr *)ptr)->magic) !=
                        BTS_FILE_HDR_MAGIC) {
                nfc_err(&drv->pdev->dev, "wrong bts magic number\n");
                rc = -EINVAL;
                goto release_fw;
        }

        /* remove the BTS header */
        len -= sizeof(struct bts_file_hdr);
        ptr += sizeof(struct bts_file_hdr);

        while (len > 0) {
                action_type =
                        __le16_to_cpu(((struct bts_file_action *)ptr)->type);
                action_len =
                        __le16_to_cpu(((struct bts_file_action *)ptr)->len);

                dev_dbg(&drv->pdev->dev, "bts_file_action type %d, len %d\n",
                        action_type, action_len);

                switch (action_type) {
                case BTS_FILE_ACTION_TYPE_SEND_CMD:
                        rc = nfcwilink_send_bts_cmd(drv,
                                        ((struct bts_file_action *)ptr)->data,
                                        action_len);
                        if (rc)
                                goto release_fw;
                        break;
                }

                /* advance to the next action */
                len -= (sizeof(struct bts_file_action) + action_len);
                ptr += (sizeof(struct bts_file_action) + action_len);
        }

release_fw:
        release_firmware(fw);

exit:
        clear_bit(NFCWILINK_FW_DOWNLOAD, &drv->flags);
        return rc;
}

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

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

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

        if (!skb)
                return -EFAULT;

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

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

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

        if (test_bit(NFCWILINK_FW_DOWNLOAD, &drv->flags)) {
                nfcwilink_fw_download_receive(drv, skb);
                return 0;
        }

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

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

        nfcwilink_proto.priv_data = drv;

        init_completion(&drv->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->completed,
                        msecs_to_jiffies(NFCWILINK_REGISTER_TIMEOUT));

                        dev_dbg(&drv->pdev->dev,
                                "wait_for_completion_timeout returned %ld\n",
                                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_err(&drv->pdev->dev,
                                        "st_register_cb failed %d\n", rc);
                                goto clear_exit;
                        }
                } else {
                        nfc_err(&drv->pdev->dev, "st_register failed %d\n", rc);
                        goto clear_exit;
                }
        }

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

        if (nfcwilink_download_fw(drv)) {
                nfc_err(&drv->pdev->dev, "nfcwilink_download_fw failed %d\n",
                        rc);
                /* open should succeed, even if the FW download failed */
        }

        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;

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

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

        drv->st_write = NULL;

        return rc;
}

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

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

        if (!test_bit(NFCWILINK_RUNNING, &drv->flags)) {
                kfree_skb(skb);
                return -EINVAL;
        }

        /* add the ST hdr to the start of the buffer */
        hdr.len = cpu_to_le16(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_err(&drv->pdev->dev, "st_write failed %ld\n", 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)
{
        struct nfcwilink *drv;
        int rc;
        __u32 protocols;

        drv = devm_kzalloc(&pdev->dev, 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_ISO14443_B_MASK
                | NFC_PROTO_NFC_DEP_MASK;

        drv->ndev = nci_allocate_device(&nfcwilink_ops,
                                        protocols,
                                        NFCWILINK_HDR_LEN,
                                        0);
        if (!drv->ndev) {
                nfc_err(&pdev->dev, "nci_allocate_device failed\n");
                rc = -ENOMEM;
                goto 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_err(&pdev->dev, "nci_register_device failed %d\n", rc);
                goto free_dev_exit;
        }

        dev_set_drvdata(&pdev->dev, drv);

        goto exit;

free_dev_exit:
        nci_free_device(drv->ndev);

exit:
        return rc;
}

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

        if (!drv)
                return -EFAULT;

        ndev = drv->ndev;

        nci_unregister_device(ndev);
        nci_free_device(ndev);

        return 0;
}

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

module_platform_driver(nfcwilink_driver);

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

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