root/drivers/nfc/microread/microread.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * HCI based Driver for Inside Secure microread NFC Chip
 *
 * Copyright (C) 2013  Intel Corporation. All rights reserved.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/crc-ccitt.h>

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

#include "microread.h"

/* Proprietary gates, events, commands and registers */
/* Admin */
#define MICROREAD_GATE_ID_ADM NFC_HCI_ADMIN_GATE
#define MICROREAD_GATE_ID_MGT 0x01
#define MICROREAD_GATE_ID_OS 0x02
#define MICROREAD_GATE_ID_TESTRF 0x03
#define MICROREAD_GATE_ID_LOOPBACK NFC_HCI_LOOPBACK_GATE
#define MICROREAD_GATE_ID_IDT NFC_HCI_ID_MGMT_GATE
#define MICROREAD_GATE_ID_LMS NFC_HCI_LINK_MGMT_GATE

/* Reader */
#define MICROREAD_GATE_ID_MREAD_GEN 0x10
#define MICROREAD_GATE_ID_MREAD_ISO_B NFC_HCI_RF_READER_B_GATE
#define MICROREAD_GATE_ID_MREAD_NFC_T1 0x12
#define MICROREAD_GATE_ID_MREAD_ISO_A NFC_HCI_RF_READER_A_GATE
#define MICROREAD_GATE_ID_MREAD_NFC_T3 0x14
#define MICROREAD_GATE_ID_MREAD_ISO_15_3 0x15
#define MICROREAD_GATE_ID_MREAD_ISO_15_2 0x16
#define MICROREAD_GATE_ID_MREAD_ISO_B_3 0x17
#define MICROREAD_GATE_ID_MREAD_BPRIME 0x18
#define MICROREAD_GATE_ID_MREAD_ISO_A_3 0x19

/* Card */
#define MICROREAD_GATE_ID_MCARD_GEN 0x20
#define MICROREAD_GATE_ID_MCARD_ISO_B 0x21
#define MICROREAD_GATE_ID_MCARD_BPRIME 0x22
#define MICROREAD_GATE_ID_MCARD_ISO_A 0x23
#define MICROREAD_GATE_ID_MCARD_NFC_T3 0x24
#define MICROREAD_GATE_ID_MCARD_ISO_15_3 0x25
#define MICROREAD_GATE_ID_MCARD_ISO_15_2 0x26
#define MICROREAD_GATE_ID_MCARD_ISO_B_2 0x27
#define MICROREAD_GATE_ID_MCARD_ISO_CUSTOM 0x28
#define MICROREAD_GATE_ID_SECURE_ELEMENT 0x2F

/* P2P */
#define MICROREAD_GATE_ID_P2P_GEN 0x30
#define MICROREAD_GATE_ID_P2P_TARGET 0x31
#define MICROREAD_PAR_P2P_TARGET_MODE 0x01
#define MICROREAD_PAR_P2P_TARGET_GT 0x04
#define MICROREAD_GATE_ID_P2P_INITIATOR 0x32
#define MICROREAD_PAR_P2P_INITIATOR_GI 0x01
#define MICROREAD_PAR_P2P_INITIATOR_GT 0x03

/* Those pipes are created/opened by default in the chip */
#define MICROREAD_PIPE_ID_LMS 0x00
#define MICROREAD_PIPE_ID_ADMIN 0x01
#define MICROREAD_PIPE_ID_MGT 0x02
#define MICROREAD_PIPE_ID_OS 0x03
#define MICROREAD_PIPE_ID_HDS_LOOPBACK 0x04
#define MICROREAD_PIPE_ID_HDS_IDT 0x05
#define MICROREAD_PIPE_ID_HDS_MCARD_ISO_B 0x08
#define MICROREAD_PIPE_ID_HDS_MCARD_ISO_BPRIME 0x09
#define MICROREAD_PIPE_ID_HDS_MCARD_ISO_A 0x0A
#define MICROREAD_PIPE_ID_HDS_MCARD_ISO_15_3 0x0B
#define MICROREAD_PIPE_ID_HDS_MCARD_ISO_15_2 0x0C
#define MICROREAD_PIPE_ID_HDS_MCARD_NFC_T3 0x0D
#define MICROREAD_PIPE_ID_HDS_MCARD_ISO_B_2 0x0E
#define MICROREAD_PIPE_ID_HDS_MCARD_CUSTOM 0x0F
#define MICROREAD_PIPE_ID_HDS_MREAD_ISO_B 0x10
#define MICROREAD_PIPE_ID_HDS_MREAD_NFC_T1 0x11
#define MICROREAD_PIPE_ID_HDS_MREAD_ISO_A 0x12
#define MICROREAD_PIPE_ID_HDS_MREAD_ISO_15_3 0x13
#define MICROREAD_PIPE_ID_HDS_MREAD_ISO_15_2 0x14
#define MICROREAD_PIPE_ID_HDS_MREAD_NFC_T3 0x15
#define MICROREAD_PIPE_ID_HDS_MREAD_ISO_B_3 0x16
#define MICROREAD_PIPE_ID_HDS_MREAD_BPRIME 0x17
#define MICROREAD_PIPE_ID_HDS_MREAD_ISO_A_3 0x18
#define MICROREAD_PIPE_ID_HDS_MREAD_GEN 0x1B
#define MICROREAD_PIPE_ID_HDS_STACKED_ELEMENT 0x1C
#define MICROREAD_PIPE_ID_HDS_INSTANCES 0x1D
#define MICROREAD_PIPE_ID_HDS_TESTRF 0x1E
#define MICROREAD_PIPE_ID_HDS_P2P_TARGET 0x1F
#define MICROREAD_PIPE_ID_HDS_P2P_INITIATOR 0x20

/* Events */
#define MICROREAD_EVT_MREAD_DISCOVERY_OCCURED NFC_HCI_EVT_TARGET_DISCOVERED
#define MICROREAD_EVT_MREAD_CARD_FOUND 0x3D
#define MICROREAD_EMCF_A_ATQA 0
#define MICROREAD_EMCF_A_SAK 2
#define MICROREAD_EMCF_A_LEN 3
#define MICROREAD_EMCF_A_UID 4
#define MICROREAD_EMCF_A3_ATQA 0
#define MICROREAD_EMCF_A3_SAK 2
#define MICROREAD_EMCF_A3_LEN 3
#define MICROREAD_EMCF_A3_UID 4
#define MICROREAD_EMCF_B_UID 0
#define MICROREAD_EMCF_T1_ATQA 0
#define MICROREAD_EMCF_T1_UID 4
#define MICROREAD_EMCF_T3_UID 0
#define MICROREAD_EVT_MREAD_DISCOVERY_START NFC_HCI_EVT_READER_REQUESTED
#define MICROREAD_EVT_MREAD_DISCOVERY_START_SOME 0x3E
#define MICROREAD_EVT_MREAD_DISCOVERY_STOP NFC_HCI_EVT_END_OPERATION
#define MICROREAD_EVT_MREAD_SIM_REQUESTS 0x3F
#define MICROREAD_EVT_MCARD_EXCHANGE NFC_HCI_EVT_TARGET_DISCOVERED
#define MICROREAD_EVT_P2P_INITIATOR_EXCHANGE_TO_RF 0x20
#define MICROREAD_EVT_P2P_INITIATOR_EXCHANGE_FROM_RF 0x21
#define MICROREAD_EVT_MCARD_FIELD_ON 0x11
#define MICROREAD_EVT_P2P_TARGET_ACTIVATED 0x13
#define MICROREAD_EVT_P2P_TARGET_DEACTIVATED 0x12
#define MICROREAD_EVT_MCARD_FIELD_OFF 0x14

/* Commands */
#define MICROREAD_CMD_MREAD_EXCHANGE 0x10
#define MICROREAD_CMD_MREAD_SUBSCRIBE 0x3F

/* Hosts IDs */
#define MICROREAD_ELT_ID_HDS NFC_HCI_TERMINAL_HOST_ID
#define MICROREAD_ELT_ID_SIM NFC_HCI_UICC_HOST_ID
#define MICROREAD_ELT_ID_SE1 0x03
#define MICROREAD_ELT_ID_SE2 0x04
#define MICROREAD_ELT_ID_SE3 0x05

static const struct nfc_hci_gate microread_gates[] = {
        {MICROREAD_GATE_ID_ADM, MICROREAD_PIPE_ID_ADMIN},
        {MICROREAD_GATE_ID_LOOPBACK, MICROREAD_PIPE_ID_HDS_LOOPBACK},
        {MICROREAD_GATE_ID_IDT, MICROREAD_PIPE_ID_HDS_IDT},
        {MICROREAD_GATE_ID_LMS, MICROREAD_PIPE_ID_LMS},
        {MICROREAD_GATE_ID_MREAD_ISO_B, MICROREAD_PIPE_ID_HDS_MREAD_ISO_B},
        {MICROREAD_GATE_ID_MREAD_ISO_A, MICROREAD_PIPE_ID_HDS_MREAD_ISO_A},
        {MICROREAD_GATE_ID_MREAD_ISO_A_3, MICROREAD_PIPE_ID_HDS_MREAD_ISO_A_3},
        {MICROREAD_GATE_ID_MGT, MICROREAD_PIPE_ID_MGT},
        {MICROREAD_GATE_ID_OS, MICROREAD_PIPE_ID_OS},
        {MICROREAD_GATE_ID_MREAD_NFC_T1, MICROREAD_PIPE_ID_HDS_MREAD_NFC_T1},
        {MICROREAD_GATE_ID_MREAD_NFC_T3, MICROREAD_PIPE_ID_HDS_MREAD_NFC_T3},
        {MICROREAD_GATE_ID_P2P_TARGET, MICROREAD_PIPE_ID_HDS_P2P_TARGET},
        {MICROREAD_GATE_ID_P2P_INITIATOR, MICROREAD_PIPE_ID_HDS_P2P_INITIATOR}
};

/* Largest headroom needed for outgoing custom commands */
#define MICROREAD_CMDS_HEADROOM 2
#define MICROREAD_CMD_TAILROOM  2

struct microread_info {
        const struct nfc_phy_ops *phy_ops;
        void *phy_id;

        struct nfc_hci_dev *hdev;

        int async_cb_type;
        data_exchange_cb_t async_cb;
        void *async_cb_context;
};

static int microread_open(struct nfc_hci_dev *hdev)
{
        struct microread_info *info = nfc_hci_get_clientdata(hdev);

        return info->phy_ops->enable(info->phy_id);
}

static void microread_close(struct nfc_hci_dev *hdev)
{
        struct microread_info *info = nfc_hci_get_clientdata(hdev);

        info->phy_ops->disable(info->phy_id);
}

static int microread_hci_ready(struct nfc_hci_dev *hdev)
{
        int r;
        u8 param[4];

        param[0] = 0x03;
        r = nfc_hci_send_cmd(hdev, MICROREAD_GATE_ID_MREAD_ISO_A,
                             MICROREAD_CMD_MREAD_SUBSCRIBE, param, 1, NULL);
        if (r)
                return r;

        r = nfc_hci_send_cmd(hdev, MICROREAD_GATE_ID_MREAD_ISO_A_3,
                             MICROREAD_CMD_MREAD_SUBSCRIBE, NULL, 0, NULL);
        if (r)
                return r;

        param[0] = 0x00;
        param[1] = 0x03;
        param[2] = 0x00;
        r = nfc_hci_send_cmd(hdev, MICROREAD_GATE_ID_MREAD_ISO_B,
                             MICROREAD_CMD_MREAD_SUBSCRIBE, param, 3, NULL);
        if (r)
                return r;

        r = nfc_hci_send_cmd(hdev, MICROREAD_GATE_ID_MREAD_NFC_T1,
                             MICROREAD_CMD_MREAD_SUBSCRIBE, NULL, 0, NULL);
        if (r)
                return r;

        param[0] = 0xFF;
        param[1] = 0xFF;
        param[2] = 0x00;
        param[3] = 0x00;
        r = nfc_hci_send_cmd(hdev, MICROREAD_GATE_ID_MREAD_NFC_T3,
                             MICROREAD_CMD_MREAD_SUBSCRIBE, param, 4, NULL);

        return r;
}

static int microread_xmit(struct nfc_hci_dev *hdev, struct sk_buff *skb)
{
        struct microread_info *info = nfc_hci_get_clientdata(hdev);

        return info->phy_ops->write(info->phy_id, skb);
}

static int microread_start_poll(struct nfc_hci_dev *hdev,
                                u32 im_protocols, u32 tm_protocols)
{
        int r;

        u8 param[2];
        u8 mode;

        param[0] = 0x00;
        param[1] = 0x00;

        if (im_protocols & NFC_PROTO_ISO14443_MASK)
                param[0] |= (1 << 2);

        if (im_protocols & NFC_PROTO_ISO14443_B_MASK)
                param[0] |= 1;

        if (im_protocols & NFC_PROTO_MIFARE_MASK)
                param[1] |= 1;

        if (im_protocols & NFC_PROTO_JEWEL_MASK)
                param[0] |= (1 << 1);

        if (im_protocols & NFC_PROTO_FELICA_MASK)
                param[0] |= (1 << 5);

        if (im_protocols & NFC_PROTO_NFC_DEP_MASK)
                param[1] |= (1 << 1);

        if ((im_protocols | tm_protocols) & NFC_PROTO_NFC_DEP_MASK) {
                hdev->gb = nfc_get_local_general_bytes(hdev->ndev,
                                                       &hdev->gb_len);
                if (hdev->gb == NULL || hdev->gb_len == 0) {
                        im_protocols &= ~NFC_PROTO_NFC_DEP_MASK;
                        tm_protocols &= ~NFC_PROTO_NFC_DEP_MASK;
                }
        }

        r = nfc_hci_send_event(hdev, MICROREAD_GATE_ID_MREAD_ISO_A,
                               MICROREAD_EVT_MREAD_DISCOVERY_STOP, NULL, 0);
        if (r)
                return r;

        mode = 0xff;
        r = nfc_hci_set_param(hdev, MICROREAD_GATE_ID_P2P_TARGET,
                              MICROREAD_PAR_P2P_TARGET_MODE, &mode, 1);
        if (r)
                return r;

        if (im_protocols & NFC_PROTO_NFC_DEP_MASK) {
                r = nfc_hci_set_param(hdev, MICROREAD_GATE_ID_P2P_INITIATOR,
                                      MICROREAD_PAR_P2P_INITIATOR_GI,
                                      hdev->gb, hdev->gb_len);
                if (r)
                        return r;
        }

        if (tm_protocols & NFC_PROTO_NFC_DEP_MASK) {
                r = nfc_hci_set_param(hdev, MICROREAD_GATE_ID_P2P_TARGET,
                                      MICROREAD_PAR_P2P_TARGET_GT,
                                      hdev->gb, hdev->gb_len);
                if (r)
                        return r;

                mode = 0x02;
                r = nfc_hci_set_param(hdev, MICROREAD_GATE_ID_P2P_TARGET,
                                      MICROREAD_PAR_P2P_TARGET_MODE, &mode, 1);
                if (r)
                        return r;
        }

        return nfc_hci_send_event(hdev, MICROREAD_GATE_ID_MREAD_ISO_A,
                                  MICROREAD_EVT_MREAD_DISCOVERY_START_SOME,
                                  param, 2);
}

static int microread_dep_link_up(struct nfc_hci_dev *hdev,
                                struct nfc_target *target, u8 comm_mode,
                                u8 *gb, size_t gb_len)
{
        struct sk_buff *rgb_skb = NULL;
        int r;

        r = nfc_hci_get_param(hdev, target->hci_reader_gate,
                              MICROREAD_PAR_P2P_INITIATOR_GT, &rgb_skb);
        if (r < 0)
                return r;

        if (rgb_skb->len == 0 || rgb_skb->len > NFC_GB_MAXSIZE) {
                r = -EPROTO;
                goto exit;
        }

        r = nfc_set_remote_general_bytes(hdev->ndev, rgb_skb->data,
                                         rgb_skb->len);
        if (r == 0)
                r = nfc_dep_link_is_up(hdev->ndev, target->idx, comm_mode,
                                       NFC_RF_INITIATOR);
exit:
        kfree_skb(rgb_skb);

        return r;
}

static int microread_dep_link_down(struct nfc_hci_dev *hdev)
{
        return nfc_hci_send_event(hdev, MICROREAD_GATE_ID_P2P_INITIATOR,
                                  MICROREAD_EVT_MREAD_DISCOVERY_STOP, NULL, 0);
}

static int microread_target_from_gate(struct nfc_hci_dev *hdev, u8 gate,
                                      struct nfc_target *target)
{
        switch (gate) {
        case MICROREAD_GATE_ID_P2P_INITIATOR:
                target->supported_protocols = NFC_PROTO_NFC_DEP_MASK;
                break;
        default:
                return -EPROTO;
        }

        return 0;
}

static int microread_complete_target_discovered(struct nfc_hci_dev *hdev,
                                                u8 gate,
                                                struct nfc_target *target)
{
        return 0;
}

#define MICROREAD_CB_TYPE_READER_ALL 1

static void microread_im_transceive_cb(void *context, struct sk_buff *skb,
                                       int err)
{
        const struct microread_info *info = context;

        switch (info->async_cb_type) {
        case MICROREAD_CB_TYPE_READER_ALL:
                if (err == 0) {
                        if (skb->len == 0) {
                                kfree_skb(skb);
                                info->async_cb(info->async_cb_context, NULL,
                                               -EPROTO);
                                return;
                        }

                        if (skb->data[skb->len - 1] != 0) {
                                err = nfc_hci_result_to_errno(
                                                       skb->data[skb->len - 1]);
                                kfree_skb(skb);
                                info->async_cb(info->async_cb_context, NULL,
                                               err);
                                return;
                        }

                        skb_trim(skb, skb->len - 1);    /* RF Error ind. */
                }
                info->async_cb(info->async_cb_context, skb, err);
                break;
        default:
                if (err == 0)
                        kfree_skb(skb);
                break;
        }
}

/*
 * Returns:
 * <= 0: driver handled the data exchange
 *    1: driver doesn't especially handle, please do standard processing
 */
static int microread_im_transceive(struct nfc_hci_dev *hdev,
                                   struct nfc_target *target,
                                   struct sk_buff *skb, data_exchange_cb_t cb,
                                   void *cb_context)
{
        struct microread_info *info = nfc_hci_get_clientdata(hdev);
        u8 control_bits;
        u16 crc;

        pr_info("data exchange to gate 0x%x\n", target->hci_reader_gate);

        if (target->hci_reader_gate == MICROREAD_GATE_ID_P2P_INITIATOR) {
                *(u8 *)skb_push(skb, 1) = 0;

                return nfc_hci_send_event(hdev, target->hci_reader_gate,
                                     MICROREAD_EVT_P2P_INITIATOR_EXCHANGE_TO_RF,
                                     skb->data, skb->len);
        }

        switch (target->hci_reader_gate) {
        case MICROREAD_GATE_ID_MREAD_ISO_A:
                control_bits = 0xCB;
                break;
        case MICROREAD_GATE_ID_MREAD_ISO_A_3:
                control_bits = 0xCB;
                break;
        case MICROREAD_GATE_ID_MREAD_ISO_B:
                control_bits = 0xCB;
                break;
        case MICROREAD_GATE_ID_MREAD_NFC_T1:
                control_bits = 0x1B;

                crc = crc_ccitt(0xffff, skb->data, skb->len);
                crc = ~crc;
                skb_put_u8(skb, crc & 0xff);
                skb_put_u8(skb, crc >> 8);
                break;
        case MICROREAD_GATE_ID_MREAD_NFC_T3:
                control_bits = 0xDB;
                break;
        default:
                pr_info("Abort im_transceive to invalid gate 0x%x\n",
                        target->hci_reader_gate);
                return 1;
        }

        *(u8 *)skb_push(skb, 1) = control_bits;

        info->async_cb_type = MICROREAD_CB_TYPE_READER_ALL;
        info->async_cb = cb;
        info->async_cb_context = cb_context;

        return nfc_hci_send_cmd_async(hdev, target->hci_reader_gate,
                                      MICROREAD_CMD_MREAD_EXCHANGE,
                                      skb->data, skb->len,
                                      microread_im_transceive_cb, info);
}

static int microread_tm_send(struct nfc_hci_dev *hdev, struct sk_buff *skb)
{
        int r;

        r = nfc_hci_send_event(hdev, MICROREAD_GATE_ID_P2P_TARGET,
                               MICROREAD_EVT_MCARD_EXCHANGE,
                               skb->data, skb->len);

        kfree_skb(skb);

        return r;
}

static void microread_target_discovered(struct nfc_hci_dev *hdev, u8 gate,
                                        struct sk_buff *skb)
{
        struct nfc_target *targets;
        int r = 0;

        pr_info("target discovered to gate 0x%x\n", gate);

        targets = kzalloc_obj(struct nfc_target);
        if (targets == NULL) {
                r = -ENOMEM;
                goto exit;
        }

        targets->hci_reader_gate = gate;

        switch (gate) {
        case MICROREAD_GATE_ID_MREAD_ISO_A:
                targets->supported_protocols =
                      nfc_hci_sak_to_protocol(skb->data[MICROREAD_EMCF_A_SAK]);
                targets->sens_res =
                         be16_to_cpu(*(u16 *)&skb->data[MICROREAD_EMCF_A_ATQA]);
                targets->sel_res = skb->data[MICROREAD_EMCF_A_SAK];
                targets->nfcid1_len = skb->data[MICROREAD_EMCF_A_LEN];
                if (targets->nfcid1_len > sizeof(targets->nfcid1)) {
                        r = -EINVAL;
                        goto exit_free;
                }
                memcpy(targets->nfcid1, &skb->data[MICROREAD_EMCF_A_UID],
                       targets->nfcid1_len);
                break;
        case MICROREAD_GATE_ID_MREAD_ISO_A_3:
                targets->supported_protocols =
                      nfc_hci_sak_to_protocol(skb->data[MICROREAD_EMCF_A3_SAK]);
                targets->sens_res =
                         be16_to_cpu(*(u16 *)&skb->data[MICROREAD_EMCF_A3_ATQA]);
                targets->sel_res = skb->data[MICROREAD_EMCF_A3_SAK];
                targets->nfcid1_len = skb->data[MICROREAD_EMCF_A3_LEN];
                if (targets->nfcid1_len > sizeof(targets->nfcid1)) {
                        r = -EINVAL;
                        goto exit_free;
                }
                memcpy(targets->nfcid1, &skb->data[MICROREAD_EMCF_A3_UID],
                       targets->nfcid1_len);
                break;
        case MICROREAD_GATE_ID_MREAD_ISO_B:
                targets->supported_protocols = NFC_PROTO_ISO14443_B_MASK;
                memcpy(targets->nfcid1, &skb->data[MICROREAD_EMCF_B_UID], 4);
                targets->nfcid1_len = 4;
                break;
        case MICROREAD_GATE_ID_MREAD_NFC_T1:
                targets->supported_protocols = NFC_PROTO_JEWEL_MASK;
                targets->sens_res =
                        le16_to_cpu(*(u16 *)&skb->data[MICROREAD_EMCF_T1_ATQA]);
                memcpy(targets->nfcid1, &skb->data[MICROREAD_EMCF_T1_UID], 4);
                targets->nfcid1_len = 4;
                break;
        case MICROREAD_GATE_ID_MREAD_NFC_T3:
                targets->supported_protocols = NFC_PROTO_FELICA_MASK;
                memcpy(targets->nfcid1, &skb->data[MICROREAD_EMCF_T3_UID], 8);
                targets->nfcid1_len = 8;
                break;
        default:
                pr_info("discard target discovered to gate 0x%x\n", gate);
                goto exit_free;
        }

        r = nfc_targets_found(hdev->ndev, targets, 1);

exit_free:
        kfree(targets);

exit:
        kfree_skb(skb);

        if (r)
                pr_err("Failed to handle discovered target err=%d\n", r);
}

static int microread_event_received(struct nfc_hci_dev *hdev, u8 pipe,
                                     u8 event, struct sk_buff *skb)
{
        int r;
        u8 gate = hdev->pipes[pipe].gate;
        u8 mode;

        pr_info("Microread received event 0x%x to gate 0x%x\n", event, gate);

        switch (event) {
        case MICROREAD_EVT_MREAD_CARD_FOUND:
                microread_target_discovered(hdev, gate, skb);
                return 0;

        case MICROREAD_EVT_P2P_INITIATOR_EXCHANGE_FROM_RF:
                if (skb->len < 1) {
                        kfree_skb(skb);
                        return -EPROTO;
                }

                if (skb->data[skb->len - 1]) {
                        kfree_skb(skb);
                        return -EIO;
                }

                skb_trim(skb, skb->len - 1);

                r = nfc_tm_data_received(hdev->ndev, skb);
                break;

        case MICROREAD_EVT_MCARD_FIELD_ON:
        case MICROREAD_EVT_MCARD_FIELD_OFF:
                kfree_skb(skb);
                return 0;

        case MICROREAD_EVT_P2P_TARGET_ACTIVATED:
                r = nfc_tm_activated(hdev->ndev, NFC_PROTO_NFC_DEP_MASK,
                                     NFC_COMM_PASSIVE, skb->data,
                                     skb->len);

                kfree_skb(skb);
                break;

        case MICROREAD_EVT_MCARD_EXCHANGE:
                if (skb->len < 1) {
                        kfree_skb(skb);
                        return -EPROTO;
                }

                if (skb->data[skb->len-1]) {
                        kfree_skb(skb);
                        return -EIO;
                }

                skb_trim(skb, skb->len - 1);

                r = nfc_tm_data_received(hdev->ndev, skb);
                break;

        case MICROREAD_EVT_P2P_TARGET_DEACTIVATED:
                kfree_skb(skb);

                mode = 0xff;
                r = nfc_hci_set_param(hdev, MICROREAD_GATE_ID_P2P_TARGET,
                                      MICROREAD_PAR_P2P_TARGET_MODE, &mode, 1);
                if (r)
                        break;

                r = nfc_hci_send_event(hdev, gate,
                                       MICROREAD_EVT_MREAD_DISCOVERY_STOP, NULL,
                                       0);
                break;

        default:
                return 1;
        }

        return r;
}

static const struct nfc_hci_ops microread_hci_ops = {
        .open = microread_open,
        .close = microread_close,
        .hci_ready = microread_hci_ready,
        .xmit = microread_xmit,
        .start_poll = microread_start_poll,
        .dep_link_up = microread_dep_link_up,
        .dep_link_down = microread_dep_link_down,
        .target_from_gate = microread_target_from_gate,
        .complete_target_discovered = microread_complete_target_discovered,
        .im_transceive = microread_im_transceive,
        .tm_send = microread_tm_send,
        .check_presence = NULL,
        .event_received = microread_event_received,
};

int microread_probe(void *phy_id, const struct nfc_phy_ops *phy_ops,
                    const char *llc_name, int phy_headroom, int phy_tailroom,
                    int phy_payload, struct nfc_hci_dev **hdev)
{
        struct microread_info *info;
        unsigned long quirks = 0;
        u32 protocols;
        struct nfc_hci_init_data init_data;
        int r;

        info = kzalloc_obj(struct microread_info);
        if (!info) {
                r = -ENOMEM;
                goto err_info_alloc;
        }

        info->phy_ops = phy_ops;
        info->phy_id = phy_id;

        init_data.gate_count = ARRAY_SIZE(microread_gates);
        memcpy(init_data.gates, microread_gates, sizeof(microread_gates));

        strcpy(init_data.session_id, "MICROREA");

        set_bit(NFC_HCI_QUIRK_SHORT_CLEAR, &quirks);

        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;

        info->hdev = nfc_hci_allocate_device(&microread_hci_ops, &init_data,
                                             quirks, protocols, llc_name,
                                             phy_headroom +
                                             MICROREAD_CMDS_HEADROOM,
                                             phy_tailroom +
                                             MICROREAD_CMD_TAILROOM,
                                             phy_payload);
        if (!info->hdev) {
                pr_err("Cannot allocate nfc hdev\n");
                r = -ENOMEM;
                goto err_alloc_hdev;
        }

        nfc_hci_set_clientdata(info->hdev, info);

        r = nfc_hci_register_device(info->hdev);
        if (r)
                goto err_regdev;

        *hdev = info->hdev;

        return 0;

err_regdev:
        nfc_hci_free_device(info->hdev);

err_alloc_hdev:
        kfree(info);

err_info_alloc:
        return r;
}
EXPORT_SYMBOL(microread_probe);

void microread_remove(struct nfc_hci_dev *hdev)
{
        struct microread_info *info = nfc_hci_get_clientdata(hdev);

        nfc_hci_unregister_device(hdev);
        nfc_hci_free_device(hdev);
        kfree(info);
}
EXPORT_SYMBOL(microread_remove);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION(DRIVER_DESC);