/*
 * NFC Digital Protocol stack
 * Copyright (c) 2013, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope 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.
 *
 */

#ifndef __NFC_DIGITAL_H
#define __NFC_DIGITAL_H

#include <linux/skbuff.h>
#include <net/nfc/nfc.h>

/**
 * Configuration types for in_configure_hw and tg_configure_hw.
 */
enum {
        NFC_DIGITAL_CONFIG_RF_TECH = 0,
        NFC_DIGITAL_CONFIG_FRAMING,
};

/**
 * RF technology values passed as param argument to in_configure_hw and
 * tg_configure_hw for NFC_DIGITAL_CONFIG_RF_TECH configuration type.
 */
enum {
        NFC_DIGITAL_RF_TECH_106A = 0,
        NFC_DIGITAL_RF_TECH_212F,
        NFC_DIGITAL_RF_TECH_424F,
        NFC_DIGITAL_RF_TECH_ISO15693,
        NFC_DIGITAL_RF_TECH_106B,

        NFC_DIGITAL_RF_TECH_LAST,
};

/**
 * Framing configuration passed as param argument to in_configure_hw and
 * tg_configure_hw for NFC_DIGITAL_CONFIG_FRAMING configuration type.
 */
enum {
        NFC_DIGITAL_FRAMING_NFCA_SHORT = 0,
        NFC_DIGITAL_FRAMING_NFCA_STANDARD,
        NFC_DIGITAL_FRAMING_NFCA_STANDARD_WITH_CRC_A,
        NFC_DIGITAL_FRAMING_NFCA_ANTICOL_COMPLETE,

        NFC_DIGITAL_FRAMING_NFCA_T1T,
        NFC_DIGITAL_FRAMING_NFCA_T2T,
        NFC_DIGITAL_FRAMING_NFCA_T4T,
        NFC_DIGITAL_FRAMING_NFCA_NFC_DEP,

        NFC_DIGITAL_FRAMING_NFCF,
        NFC_DIGITAL_FRAMING_NFCF_T3T,
        NFC_DIGITAL_FRAMING_NFCF_NFC_DEP,
        NFC_DIGITAL_FRAMING_NFC_DEP_ACTIVATED,

        NFC_DIGITAL_FRAMING_ISO15693_INVENTORY,
        NFC_DIGITAL_FRAMING_ISO15693_T5T,

        NFC_DIGITAL_FRAMING_NFCB,
        NFC_DIGITAL_FRAMING_NFCB_T4T,

        NFC_DIGITAL_FRAMING_LAST,
};

#define DIGITAL_MDAA_NFCID1_SIZE 3

struct digital_tg_mdaa_params {
        u16 sens_res;
        u8 nfcid1[DIGITAL_MDAA_NFCID1_SIZE];
        u8 sel_res;

        u8 nfcid2[NFC_NFCID2_MAXSIZE];
        u16 sc;
};

struct nfc_digital_dev;

/**
 * nfc_digital_cmd_complete_t - Definition of command result callback
 *
 * @ddev: nfc_digital_device ref
 * @arg: user data
 * @resp: response data
 *
 * resp pointer can be an error code and will be checked with IS_ERR() macro.
 * The callback is responsible for freeing resp sk_buff.
 */
typedef void (*nfc_digital_cmd_complete_t)(struct nfc_digital_dev *ddev,
                                           void *arg, struct sk_buff *resp);

/**
 * Device side NFC Digital operations
 *
 * Initiator mode:
 * @in_configure_hw: Hardware configuration for RF technology and communication
 *      framing in initiator mode. This is a synchronous function.
 * @in_send_cmd: Initiator mode data exchange using RF technology and framing
 *      previously set with in_configure_hw. The peer response is returned
 *      through callback cb. If an io error occurs or the peer didn't reply
 *      within the specified timeout (ms), the error code is passed back through
 *      the resp pointer. This is an asynchronous function.
 *
 * Target mode: Only NFC-DEP protocol is supported in target mode.
 * @tg_configure_hw: Hardware configuration for RF technology and communication
 *      framing in target mode. This is a synchronous function.
 * @tg_send_cmd: Target mode data exchange using RF technology and framing
 *      previously set with tg_configure_hw. The peer next command is returned
 *      through callback cb. If an io error occurs or the peer didn't reply
 *      within the specified timeout (ms), the error code is passed back through
 *      the resp pointer. This is an asynchronous function.
 * @tg_listen: Put the device in listen mode waiting for data from the peer
 *      device. This is an asynchronous function.
 * @tg_listen_mdaa: If supported, put the device in automatic listen mode with
 *      mode detection and automatic anti-collision. In this mode, the device
 *      automatically detects the RF technology and executes the anti-collision
 *      detection using the command responses specified in mdaa_params. The
 *      mdaa_params structure contains SENS_RES, NFCID1, and SEL_RES for 106A RF
 *      tech. NFCID2 and system code (sc) for 212F and 424F. The driver returns
 *      the NFC-DEP ATR_REQ command through cb. The digital stack deducts the RF
 *      tech by analyzing the SoD of the frame containing the ATR_REQ command.
 *      This is an asynchronous function.
 * @tg_listen_md: If supported, put the device in automatic listen mode with
 *      mode detection but without automatic anti-collision. In this mode, the
 *      device automatically detects the RF technology.  What the actual
 *      RF technology is can be retrieved by calling @tg_get_rf_tech.
 *      The digital stack will then perform the appropriate anti-collision
 *      sequence.  This is an asynchronous function.
 * @tg_get_rf_tech: Required when @tg_listen_md is supported, unused otherwise.
 *      Return the RF Technology that was detected by the @tg_listen_md call.
 *      This is a synchronous function.
 *
 * @switch_rf: Turns device radio on or off. The stack does not call explicitly
 *      switch_rf to turn the radio on. A call to in|tg_configure_hw must turn
 *      the device radio on.
 * @abort_cmd: Discard the last sent command.
 *
 * Notes: Asynchronous functions have a timeout parameter. It is the driver
 *      responsibility to call the digital stack back through the
 *      nfc_digital_cmd_complete_t callback when no RF respsonse has been
 *      received within the specified time (in milliseconds). In that case the
 *      driver must set the resp sk_buff to ERR_PTR(-ETIMEDOUT).
 *      Since the digital stack serializes commands to be sent, it's mandatory
 *      for the driver to handle the timeout correctly. Otherwise the stack
 *      would not be able to send new commands, waiting for the reply of the
 *      current one.
 */
struct nfc_digital_ops {
        int (*in_configure_hw)(struct nfc_digital_dev *ddev, int type,
                               int param);
        int (*in_send_cmd)(struct nfc_digital_dev *ddev, struct sk_buff *skb,
                           u16 timeout, nfc_digital_cmd_complete_t cb,
                           void *arg);

        int (*tg_configure_hw)(struct nfc_digital_dev *ddev, int type,
                               int param);
        int (*tg_send_cmd)(struct nfc_digital_dev *ddev, struct sk_buff *skb,
                           u16 timeout, nfc_digital_cmd_complete_t cb,
                           void *arg);
        int (*tg_listen)(struct nfc_digital_dev *ddev, u16 timeout,
                         nfc_digital_cmd_complete_t cb, void *arg);
        int (*tg_listen_mdaa)(struct nfc_digital_dev *ddev,
                              struct digital_tg_mdaa_params *mdaa_params,
                              u16 timeout, nfc_digital_cmd_complete_t cb,
                              void *arg);
        int (*tg_listen_md)(struct nfc_digital_dev *ddev, u16 timeout,
                            nfc_digital_cmd_complete_t cb, void *arg);
        int (*tg_get_rf_tech)(struct nfc_digital_dev *ddev, u8 *rf_tech);

        int (*switch_rf)(struct nfc_digital_dev *ddev, bool on);
        void (*abort_cmd)(struct nfc_digital_dev *ddev);
};

#define NFC_DIGITAL_POLL_MODE_COUNT_MAX 6 /* 106A, 212F, and 424F in & tg */

typedef int (*digital_poll_t)(struct nfc_digital_dev *ddev, u8 rf_tech);

struct digital_poll_tech {
        u8 rf_tech;
        digital_poll_t poll_func;
};

/**
 * Driver capabilities - bit mask made of the following values
 *
 * @NFC_DIGITAL_DRV_CAPS_IN_CRC: The driver handles CRC calculation in initiator
 *      mode.
 * @NFC_DIGITAL_DRV_CAPS_TG_CRC: The driver handles CRC calculation in target
 *      mode.
 */
#define NFC_DIGITAL_DRV_CAPS_IN_CRC     0x0001
#define NFC_DIGITAL_DRV_CAPS_TG_CRC     0x0002

struct nfc_digital_dev {
        struct nfc_dev *nfc_dev;
        struct nfc_digital_ops *ops;

        u32 protocols;

        int tx_headroom;
        int tx_tailroom;

        u32 driver_capabilities;
        void *driver_data;

        struct digital_poll_tech poll_techs[NFC_DIGITAL_POLL_MODE_COUNT_MAX];
        u8 poll_tech_count;
        u8 poll_tech_index;
        struct mutex poll_lock;

        struct work_struct cmd_work;
        struct work_struct cmd_complete_work;
        struct list_head cmd_queue;
        struct mutex cmd_lock;

        struct work_struct poll_work;

        u8 curr_protocol;
        u8 curr_rf_tech;
        u8 curr_nfc_dep_pni;
        u8 did;

        u8 local_payload_max;
        u8 remote_payload_max;

        struct sk_buff *chaining_skb;
        struct digital_data_exch *data_exch;

        int atn_count;
        int nack_count;

        struct sk_buff *saved_skb;
        unsigned int saved_skb_len;

        u16 target_fsc;

        int (*skb_check_crc)(struct sk_buff *skb);
        void (*skb_add_crc)(struct sk_buff *skb);
};

struct nfc_digital_dev *nfc_digital_allocate_device(struct nfc_digital_ops *ops,
                                                    __u32 supported_protocols,
                                                    __u32 driver_capabilities,
                                                    int tx_headroom,
                                                    int tx_tailroom);
void nfc_digital_free_device(struct nfc_digital_dev *ndev);
int nfc_digital_register_device(struct nfc_digital_dev *ndev);
void nfc_digital_unregister_device(struct nfc_digital_dev *ndev);

static inline void nfc_digital_set_parent_dev(struct nfc_digital_dev *ndev,
                                              struct device *dev)
{
        nfc_set_parent_dev(ndev->nfc_dev, dev);
}

static inline void nfc_digital_set_drvdata(struct nfc_digital_dev *dev,
                                           void *data)
{
        dev->driver_data = data;
}

static inline void *nfc_digital_get_drvdata(struct nfc_digital_dev *dev)
{
        return dev->driver_data;
}

#endif /* __NFC_DIGITAL_H */