/** @file
 *  @brief Internal APIs for Bluetooth RFCOMM handling.
 */

/*
 * Copyright (c) 2015-2016 Intel Corporation
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <rfcomm.h>

typedef enum {
    BT_RFCOMM_CFC_UNKNOWN,
    BT_RFCOMM_CFC_NOT_SUPPORTED,
    BT_RFCOMM_CFC_SUPPORTED,
} __packed bt_rfcomm_cfc_t;

/* RFCOMM signalling connection specific context */
struct bt_rfcomm_session {
    /* L2CAP channel this context is associated with */
    struct bt_l2cap_br_chan br_chan;
    /* Response Timeout eXpired (RTX) timer */
    struct k_delayed_work rtx_work;
    /* Binary sem for aggregate fc */
    struct k_sem fc;
    struct bt_rfcomm_dlc *dlcs;
    uint16_t mtu;
    uint8_t state;
    bt_rfcomm_role_t role;
    bt_rfcomm_cfc_t cfc;
};

enum {
    BT_RFCOMM_STATE_IDLE,
    BT_RFCOMM_STATE_INIT,
    BT_RFCOMM_STATE_SECURITY_PENDING,
    BT_RFCOMM_STATE_CONNECTING,
    BT_RFCOMM_STATE_CONNECTED,
    BT_RFCOMM_STATE_CONFIG,
    BT_RFCOMM_STATE_USER_DISCONNECT,
    BT_RFCOMM_STATE_DISCONNECTING,
    BT_RFCOMM_STATE_DISCONNECTED,
};

struct bt_rfcomm_hdr {
    uint8_t address;
    uint8_t control;
    uint8_t length;
} __packed;

#define BT_RFCOMM_SABM 0x2f
#define BT_RFCOMM_UA   0x63
#define BT_RFCOMM_UIH  0xef

struct bt_rfcomm_msg_hdr {
    uint8_t type;
    uint8_t len;
} __packed;

#define BT_RFCOMM_PN 0x20
struct bt_rfcomm_pn {
    uint8_t dlci;
    uint8_t flow_ctrl;
    uint8_t priority;
    uint8_t ack_timer;
    uint16_t mtu;
    uint8_t max_retrans;
    uint8_t credits;
} __packed;

#define BT_RFCOMM_MSC 0x38
struct bt_rfcomm_msc {
    uint8_t dlci;
    uint8_t v24_signal;
} __packed;

#define BT_RFCOMM_DISC 0x43
#define BT_RFCOMM_DM   0x0f

#define BT_RFCOMM_RLS 0x14
struct bt_rfcomm_rls {
    uint8_t dlci;
    uint8_t line_status;
} __packed;

#define BT_RFCOMM_RPN 0x24
struct bt_rfcomm_rpn {
    uint8_t dlci;
    uint8_t baud_rate;
    uint8_t line_settings;
    uint8_t flow_control;
    uint8_t xon_char;
    uint8_t xoff_char;
    uint16_t param_mask;
} __packed;

#define BT_RFCOMM_TEST 0x08
#define BT_RFCOMM_NSC  0x04

#define BT_RFCOMM_FCON  0x28
#define BT_RFCOMM_FCOFF 0x18

/* Default RPN Settings */
#define BT_RFCOMM_RPN_BAUD_RATE_9600 0x03
#define BT_RFCOMM_RPN_DATA_BITS_8    0x03
#define BT_RFCOMM_RPN_STOP_BITS_1    0x00
#define BT_RFCOMM_RPN_PARITY_NONE    0x00
#define BT_RFCOMM_RPN_FLOW_NONE      0x00
#define BT_RFCOMM_RPN_XON_CHAR       0x11
#define BT_RFCOMM_RPN_XOFF_CHAR      0x13

/* Set 1 to all the param mask except reserved */
#define BT_RFCOMM_RPN_PARAM_MASK_ALL 0x3f7f

#define BT_RFCOMM_SET_LINE_SETTINGS(data, stop, parity) ((data & 0x3) |        \
                                                         ((stop & 0x1) << 2) | \
                                                         ((parity & 0x7) << 3))

/* DV = 1 IC = 0 RTR = 1 RTC = 1 FC = 0 EXT = 0 */
#define BT_RFCOMM_DEFAULT_V24_SIG 0x8d

#define BT_RFCOMM_GET_FC(v24_signal) (((v24_signal)&0x02) >> 1)

#define BT_RFCOMM_SIG_MIN_MTU 23
#define BT_RFCOMM_SIG_MAX_MTU 32767

#define BT_RFCOMM_CHECK_MTU(mtu) (!!((mtu) >= BT_RFCOMM_SIG_MIN_MTU && \
                                     (mtu) <= BT_RFCOMM_SIG_MAX_MTU))

/* Helper to calculate needed outgoing buffer size.
 * Length in rfcomm header can be two bytes depending on user data length.
 * One byte in the tail should be reserved for FCS.
 */
#define BT_RFCOMM_BUF_SIZE(mtu) (BT_BUF_RESERVE +                           \
                                 BT_HCI_ACL_HDR_SIZE + BT_L2CAP_HDR_SIZE +  \
                                 sizeof(struct bt_rfcomm_hdr) + 1 + (mtu) + \
                                 BT_RFCOMM_FCS_SIZE)

#define BT_RFCOMM_GET_DLCI(addr)       (((addr)&0xfc) >> 2)
#define BT_RFCOMM_GET_FRAME_TYPE(ctrl) ((ctrl)&0xef)
#define BT_RFCOMM_GET_MSG_TYPE(type)   (((type)&0xfc) >> 2)
#define BT_RFCOMM_GET_MSG_CR(type)     (((type)&0x02) >> 1)
#define BT_RFCOMM_GET_LEN(len)         (((len)&0xfe) >> 1)
#define BT_RFCOMM_GET_CHANNEL(dlci)    ((dlci) >> 1)
#define BT_RFCOMM_GET_PF(ctrl)         (((ctrl)&0x10) >> 4)

#define BT_RFCOMM_SET_ADDR(dlci, cr) ((((dlci)&0x3f) << 2) | \
                                      ((cr) << 1) | 0x01)
#define BT_RFCOMM_SET_CTRL(type, pf)     (((type)&0xef) | ((pf) << 4))
#define BT_RFCOMM_SET_LEN_8(len)         (((len) << 1) | 1)
#define BT_RFCOMM_SET_LEN_16(len)        ((len) << 1)
#define BT_RFCOMM_SET_MSG_TYPE(type, cr) (((type) << 2) | (cr << 1) | 0x01)

#define BT_RFCOMM_LEN_EXTENDED(len) (!((len)&0x01))

/* For CR in UIH Packet header
 * Initiating station have the C/R bit set to 1 and those sent by the
 * responding station have the C/R bit set to 0
 */
#define BT_RFCOMM_UIH_CR(role) ((role) == BT_RFCOMM_ROLE_INITIATOR)

/* For CR in Non UIH Packet header
 * Command
 * Initiator --> Responder 1
 * Responder --> Initiator 0
 * Response
 * Initiator --> Responder 0
 * Responder --> Initiator 1
 */
#define BT_RFCOMM_CMD_CR(role)  ((role) == BT_RFCOMM_ROLE_INITIATOR)
#define BT_RFCOMM_RESP_CR(role) ((role) == BT_RFCOMM_ROLE_ACCEPTOR)

/* For CR in MSG header
 * If the C/R bit is set to 1 the message is a command,
 * if it is set to 0 the message is a response.
 */
#define BT_RFCOMM_MSG_CMD_CR  1
#define BT_RFCOMM_MSG_RESP_CR 0

#define BT_RFCOMM_DLCI(role, channel) ((((channel)&0x1f) << 1) | \
                                       ((role) == BT_RFCOMM_ROLE_ACCEPTOR))

/* Excluding ext bit */
#define BT_RFCOMM_MAX_LEN_8 127

/* Length can be 2 bytes depending on data size */
#define BT_RFCOMM_HDR_SIZE (sizeof(struct bt_rfcomm_hdr) + 1)
#define BT_RFCOMM_FCS_SIZE 1

#define BT_RFCOMM_FCS_LEN_UIH     2
#define BT_RFCOMM_FCS_LEN_NON_UIH 3

/* For non UIH packets
 * The P bit set to 1 shall be used to solicit a response frame with the
 * F bit set to 1 from the other station.
 */
#define BT_RFCOMM_PF_NON_UIH 1

/* For UIH packets
 * Both stations set the P-bit to 0
 * If credit based flow control is used, If P/F is 1 then one credit byte
 * will be there after control in the frame else no credit byte.
 */
#define BT_RFCOMM_PF_UIH           0
#define BT_RFCOMM_PF_UIH_CREDIT    1
#define BT_RFCOMM_PF_UIH_NO_CREDIT 0

#define BT_RFCOMM_PN_CFC_CMD  0xf0
#define BT_RFCOMM_PN_CFC_RESP 0xe0

/* Initialize RFCOMM signal layer */
void bt_rfcomm_init(void);
