core.c

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/*
 * Copyright (C) 2011 Instituto Nokia de Tecnologia
 *
 * Authors:
 *    Lauro Ramos Venancio <[email protected]>
 *    Aloisio Almeida Jr <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": %s: " fmt, __func__

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/nfc.h>

#include <net/genetlink.h>

#include "nfc.h"

#define VERSION "0.1"

#define NFC_CHECK_PRES_FREQ_MS  2000

int nfc_devlist_generation;
DEFINE_MUTEX(nfc_devlist_mutex);

int nfc_dev_up(struct nfc_dev *dev)
{
    int rc = 0;

    pr_debug("dev_name=%s\n", dev_name(&dev->dev));

    device_lock(&dev->dev);

    if (!device_is_registered(&dev->dev)) {
        rc = -ENODEV;
        goto error;
    }

    if (dev->dev_up) {
        rc = -EALREADY;
        goto error;
    }

    if (dev->ops->dev_up)
        rc = dev->ops->dev_up(dev);

    if (!rc)
        dev->dev_up = true;

error:
    device_unlock(&dev->dev);
    return rc;
}

int nfc_dev_down(struct nfc_dev *dev)
{
    int rc = 0;

    pr_debug("dev_name=%s\n", dev_name(&dev->dev));

    device_lock(&dev->dev);

    if (!device_is_registered(&dev->dev)) {
        rc = -ENODEV;
        goto error;
    }

    if (!dev->dev_up) {
        rc = -EALREADY;
        goto error;
    }

    if (dev->polling || dev->active_target) {
        rc = -EBUSY;
        goto error;
    }

    if (dev->ops->dev_down)
        dev->ops->dev_down(dev);

    dev->dev_up = false;

error:
    device_unlock(&dev->dev);
    return rc;
}

int nfc_start_poll(struct nfc_dev *dev, u32 im_protocols, u32 tm_protocols)
{
    int rc;

    pr_debug("dev_name %s initiator protocols 0x%x target protocols 0x%x\n",
         dev_name(&dev->dev), im_protocols, tm_protocols);

    if (!im_protocols && !tm_protocols)
        return -EINVAL;

    device_lock(&dev->dev);

    if (!device_is_registered(&dev->dev)) {
        rc = -ENODEV;
        goto error;
    }

    if (dev->polling) {
        rc = -EBUSY;
        goto error;
    }

    rc = dev->ops->start_poll(dev, im_protocols, tm_protocols);
    if (!rc) {
        dev->polling = true;
        dev->rf_mode = NFC_RF_NONE;
    }

error:
    device_unlock(&dev->dev);
    return rc;
}

int nfc_stop_poll(struct nfc_dev *dev)
{
    int rc = 0;

    pr_debug("dev_name=%s\n", dev_name(&dev->dev));

    device_lock(&dev->dev);

    if (!device_is_registered(&dev->dev)) {
        rc = -ENODEV;
        goto error;
    }

    if (!dev->polling) {
        rc = -EINVAL;
        goto error;
    }

    dev->ops->stop_poll(dev);
    dev->polling = false;

error:
    device_unlock(&dev->dev);
    return rc;
}

static struct nfc_target *nfc_find_target(struct nfc_dev *dev, u32 target_idx)
{
    int i;

    if (dev->n_targets == 0)
        return NULL;

    for (i = 0; i < dev->n_targets ; i++) {
        if (dev->targets[i].idx == target_idx)
            return &dev->targets[i];
    }

    return NULL;
}

int nfc_dep_link_up(struct nfc_dev *dev, int target_index, u8 comm_mode)
{
    int rc = 0;
    u8 *gb;
    size_t gb_len;
    struct nfc_target *target;

    pr_debug("dev_name=%s comm %d\n", dev_name(&dev->dev), comm_mode);

    if (!dev->ops->dep_link_up)
        return -EOPNOTSUPP;

    device_lock(&dev->dev);

    if (!device_is_registered(&dev->dev)) {
        rc = -ENODEV;
        goto error;
    }

    if (dev->dep_link_up == true) {
        rc = -EALREADY;
        goto error;
    }

    gb = nfc_llcp_general_bytes(dev, &gb_len);
    if (gb_len > NFC_MAX_GT_LEN) {
        rc = -EINVAL;
        goto error;
    }

    target = nfc_find_target(dev, target_index);
    if (target == NULL) {
        rc = -ENOTCONN;
        goto error;
    }

    rc = dev->ops->dep_link_up(dev, target, comm_mode, gb, gb_len);
    if (!rc) {
        dev->active_target = target;
        dev->rf_mode = NFC_RF_INITIATOR;
    }

error:
    device_unlock(&dev->dev);
    return rc;
}

int nfc_dep_link_down(struct nfc_dev *dev)
{
    int rc = 0;

    pr_debug("dev_name=%s\n", dev_name(&dev->dev));

    if (!dev->ops->dep_link_down)
        return -EOPNOTSUPP;

    device_lock(&dev->dev);

    if (!device_is_registered(&dev->dev)) {
        rc = -ENODEV;
        goto error;
    }

    if (dev->dep_link_up == false) {
        rc = -EALREADY;
        goto error;
    }

    rc = dev->ops->dep_link_down(dev);
    if (!rc) {
        dev->dep_link_up = false;
        dev->active_target = NULL;
        nfc_llcp_mac_is_down(dev);
        nfc_genl_dep_link_down_event(dev);
    }

error:
    device_unlock(&dev->dev);
    return rc;
}

int nfc_dep_link_is_up(struct nfc_dev *dev, u32 target_idx,
               u8 comm_mode, u8 rf_mode)
{
    dev->dep_link_up = true;

    nfc_llcp_mac_is_up(dev, target_idx, comm_mode, rf_mode);

    return nfc_genl_dep_link_up_event(dev, target_idx, comm_mode, rf_mode);
}
EXPORT_SYMBOL(nfc_dep_link_is_up);

int nfc_activate_target(struct nfc_dev *dev, u32 target_idx, u32 protocol)
{
    int rc;
    struct nfc_target *target;

    pr_debug("dev_name=%s target_idx=%u protocol=%u\n",
         dev_name(&dev->dev), target_idx, protocol);

    device_lock(&dev->dev);

    if (!device_is_registered(&dev->dev)) {
        rc = -ENODEV;
        goto error;
    }

    if (dev->active_target) {
        rc = -EBUSY;
        goto error;
    }

    target = nfc_find_target(dev, target_idx);
    if (target == NULL) {
        rc = -ENOTCONN;
        goto error;
    }

    rc = dev->ops->activate_target(dev, target, protocol);
    if (!rc) {
        dev->active_target = target;
        dev->rf_mode = NFC_RF_INITIATOR;

        if (dev->ops->check_presence)
            mod_timer(&dev->check_pres_timer, jiffies +
                  msecs_to_jiffies(NFC_CHECK_PRES_FREQ_MS));
    }

error:
    device_unlock(&dev->dev);
    return rc;
}

int nfc_deactivate_target(struct nfc_dev *dev, u32 target_idx)
{
    int rc = 0;

    pr_debug("dev_name=%s target_idx=%u\n",
         dev_name(&dev->dev), target_idx);

    device_lock(&dev->dev);

    if (!device_is_registered(&dev->dev)) {
        rc = -ENODEV;
        goto error;
    }

    if (dev->active_target == NULL) {
        rc = -ENOTCONN;
        goto error;
    }

    if (dev->active_target->idx != target_idx) {
        rc = -ENOTCONN;
        goto error;
    }

    if (dev->ops->check_presence)
        del_timer_sync(&dev->check_pres_timer);

    dev->ops->deactivate_target(dev, dev->active_target);
    dev->active_target = NULL;

error:
    device_unlock(&dev->dev);
    return rc;
}

int nfc_data_exchange(struct nfc_dev *dev, u32 target_idx, struct sk_buff *skb,
              data_exchange_cb_t cb, void *cb_context)
{
    int rc;

    pr_debug("dev_name=%s target_idx=%u skb->len=%u\n",
         dev_name(&dev->dev), target_idx, skb->len);

    device_lock(&dev->dev);

    if (!device_is_registered(&dev->dev)) {
        rc = -ENODEV;
        kfree_skb(skb);
        goto error;
    }

    if (dev->rf_mode == NFC_RF_INITIATOR && dev->active_target != NULL) {
        if (dev->active_target->idx != target_idx) {
            rc = -EADDRNOTAVAIL;
            kfree_skb(skb);
            goto error;
        }

        if (dev->ops->check_presence)
            del_timer_sync(&dev->check_pres_timer);

        rc = dev->ops->im_transceive(dev, dev->active_target, skb, cb,
                         cb_context);

        if (!rc && dev->ops->check_presence)
            mod_timer(&dev->check_pres_timer, jiffies +
                  msecs_to_jiffies(NFC_CHECK_PRES_FREQ_MS));
    } else if (dev->rf_mode == NFC_RF_TARGET && dev->ops->tm_send != NULL) {
        rc = dev->ops->tm_send(dev, skb);
    } else {
        rc = -ENOTCONN;
        kfree_skb(skb);
        goto error;
    }


error:
    device_unlock(&dev->dev);
    return rc;
}

int nfc_set_remote_general_bytes(struct nfc_dev *dev, u8 *gb, u8 gb_len)
{
    pr_debug("dev_name=%s gb_len=%d\n", dev_name(&dev->dev), gb_len);

    if (gb_len > NFC_MAX_GT_LEN)
        return -EINVAL;

    return nfc_llcp_set_remote_gb(dev, gb, gb_len);
}
EXPORT_SYMBOL(nfc_set_remote_general_bytes);

u8 *nfc_get_local_general_bytes(struct nfc_dev *dev, size_t *gb_len)
{
    pr_debug("dev_name=%s\n", dev_name(&dev->dev));

    return nfc_llcp_general_bytes(dev, gb_len);
}
EXPORT_SYMBOL(nfc_get_local_general_bytes);

int nfc_tm_data_received(struct nfc_dev *dev, struct sk_buff *skb)
{
    /* Only LLCP target mode for now */
    if (dev->dep_link_up == false) {
        kfree_skb(skb);
        return -ENOLINK;
    }

    return nfc_llcp_data_received(dev, skb);
}
EXPORT_SYMBOL(nfc_tm_data_received);

int nfc_tm_activated(struct nfc_dev *dev, u32 protocol, u8 comm_mode,
             u8 *gb, size_t gb_len)
{
    int rc;

    device_lock(&dev->dev);

    dev->polling = false;

    if (gb != NULL) {
        rc = nfc_set_remote_general_bytes(dev, gb, gb_len);
        if (rc < 0)
            goto out;
    }

    dev->rf_mode = NFC_RF_TARGET;

    if (protocol == NFC_PROTO_NFC_DEP_MASK)
        nfc_dep_link_is_up(dev, 0, comm_mode, NFC_RF_TARGET);

    rc = nfc_genl_tm_activated(dev, protocol);

out:
    device_unlock(&dev->dev);

    return rc;
}
EXPORT_SYMBOL(nfc_tm_activated);

int nfc_tm_deactivated(struct nfc_dev *dev)
{
    dev->dep_link_up = false;

    return nfc_genl_tm_deactivated(dev);
}
EXPORT_SYMBOL(nfc_tm_deactivated);

struct sk_buff *nfc_alloc_send_skb(struct nfc_dev *dev, struct sock *sk,
                   unsigned int flags, unsigned int size,
                   unsigned int *err)
{
    struct sk_buff *skb;
    unsigned int total_size;

    total_size = size +
        dev->tx_headroom + dev->tx_tailroom + NFC_HEADER_SIZE;

    skb = sock_alloc_send_skb(sk, total_size, flags & MSG_DONTWAIT, err);
    if (skb)
        skb_reserve(skb, dev->tx_headroom + NFC_HEADER_SIZE);

    return skb;
}

struct sk_buff *nfc_alloc_recv_skb(unsigned int size, gfp_t gfp)
{
    struct sk_buff *skb;
    unsigned int total_size;

    total_size = size + 1;
    skb = alloc_skb(total_size, gfp);

    if (skb)
        skb_reserve(skb, 1);

    return skb;
}
EXPORT_SYMBOL(nfc_alloc_recv_skb);

int nfc_targets_found(struct nfc_dev *dev,
              struct nfc_target *targets, int n_targets)
{
    int i;

    pr_debug("dev_name=%s n_targets=%d\n", dev_name(&dev->dev), n_targets);

    for (i = 0; i < n_targets; i++)
        targets[i].idx = dev->target_next_idx++;

    device_lock(&dev->dev);

    if (dev->polling == false) {
        device_unlock(&dev->dev);
        return 0;
    }

    dev->polling = false;

    dev->targets_generation++;

    kfree(dev->targets);
    dev->targets = NULL;

    if (targets) {
        dev->targets = kmemdup(targets,
                       n_targets * sizeof(struct nfc_target),
                       GFP_ATOMIC);

        if (!dev->targets) {
            dev->n_targets = 0;
            device_unlock(&dev->dev);
            return -ENOMEM;
        }
    }

    dev->n_targets = n_targets;
    device_unlock(&dev->dev);

    nfc_genl_targets_found(dev);

    return 0;
}
EXPORT_SYMBOL(nfc_targets_found);

int nfc_target_lost(struct nfc_dev *dev, u32 target_idx)
{
    struct nfc_target *tg;
    int i;

    pr_debug("dev_name %s n_target %d\n", dev_name(&dev->dev), target_idx);

    device_lock(&dev->dev);

    for (i = 0; i < dev->n_targets; i++) {
        tg = &dev->targets[i];
        if (tg->idx == target_idx)
            break;
    }

    if (i == dev->n_targets) {
        device_unlock(&dev->dev);
        return -EINVAL;
    }

    dev->targets_generation++;
    dev->n_targets--;
    dev->active_target = NULL;

    if (dev->n_targets) {
        memcpy(&dev->targets[i], &dev->targets[i + 1],
               (dev->n_targets - i) * sizeof(struct nfc_target));
    } else {
        kfree(dev->targets);
        dev->targets = NULL;
    }

    device_unlock(&dev->dev);

    nfc_genl_target_lost(dev, target_idx);

    return 0;
}
EXPORT_SYMBOL(nfc_target_lost);

inline void nfc_driver_failure(struct nfc_dev *dev, int err)
{
    nfc_targets_found(dev, NULL, 0);
}
EXPORT_SYMBOL(nfc_driver_failure);

static void nfc_release(struct device *d)
{
    struct nfc_dev *dev = to_nfc_dev(d);

    pr_debug("dev_name=%s\n", dev_name(&dev->dev));

    if (dev->ops->check_presence) {
        del_timer_sync(&dev->check_pres_timer);
        cancel_work_sync(&dev->check_pres_work);
    }

    nfc_genl_data_exit(&dev->genl_data);
    kfree(dev->targets);
    kfree(dev);
}

static void nfc_check_pres_work(struct work_struct *work)
{
    struct nfc_dev *dev = container_of(work, struct nfc_dev,
                       check_pres_work);
    int rc;

    device_lock(&dev->dev);

    if (dev->active_target && timer_pending(&dev->check_pres_timer) == 0) {
        rc = dev->ops->check_presence(dev, dev->active_target);
        if (!rc) {
            mod_timer(&dev->check_pres_timer, jiffies +
                  msecs_to_jiffies(NFC_CHECK_PRES_FREQ_MS));
        } else {
            u32 active_target_idx = dev->active_target->idx;
            device_unlock(&dev->dev);
            nfc_target_lost(dev, active_target_idx);
            return;
        }
    }

    device_unlock(&dev->dev);
}

static void nfc_check_pres_timeout(unsigned long data)
{
    struct nfc_dev *dev = (struct nfc_dev *)data;

    schedule_work(&dev->check_pres_work);
}

struct class nfc_class = {
    .name = "nfc",
    .dev_release = nfc_release,
};
EXPORT_SYMBOL(nfc_class);

static int match_idx(struct device *d, void *data)
{
    struct nfc_dev *dev = to_nfc_dev(d);
    unsigned int *idx = data;

    return dev->idx == *idx;
}

struct nfc_dev *nfc_get_device(unsigned int idx)
{
    struct device *d;

    d = class_find_device(&nfc_class, NULL, &idx, match_idx);
    if (!d)
        return NULL;

    return to_nfc_dev(d);
}

struct nfc_dev *nfc_allocate_device(struct nfc_ops *ops,
                    u32 supported_protocols,
                    int tx_headroom, int tx_tailroom)
{
    static atomic_t dev_no = ATOMIC_INIT(0);
    struct nfc_dev *dev;

    if (!ops->start_poll || !ops->stop_poll || !ops->activate_target ||
        !ops->deactivate_target || !ops->im_transceive)
        return NULL;

    if (!supported_protocols)
        return NULL;

    dev = kzalloc(sizeof(struct nfc_dev), GFP_KERNEL);
    if (!dev)
        return NULL;

    dev->dev.class = &nfc_class;
    dev->idx = atomic_inc_return(&dev_no) - 1;
    dev_set_name(&dev->dev, "nfc%d", dev->idx);
    device_initialize(&dev->dev);

    dev->ops = ops;
    dev->supported_protocols = supported_protocols;
    dev->tx_headroom = tx_headroom;
    dev->tx_tailroom = tx_tailroom;

    nfc_genl_data_init(&dev->genl_data);


    /* first generation must not be 0 */
    dev->targets_generation = 1;

    if (ops->check_presence) {
        init_timer(&dev->check_pres_timer);
        dev->check_pres_timer.data = (unsigned long)dev;
        dev->check_pres_timer.function = nfc_check_pres_timeout;

        INIT_WORK(&dev->check_pres_work, nfc_check_pres_work);
    }

    return dev;
}
EXPORT_SYMBOL(nfc_allocate_device);

int nfc_register_device(struct nfc_dev *dev)
{
    int rc;

    pr_debug("dev_name=%s\n", dev_name(&dev->dev));

    mutex_lock(&nfc_devlist_mutex);
    nfc_devlist_generation++;
    rc = device_add(&dev->dev);
    mutex_unlock(&nfc_devlist_mutex);

    if (rc < 0)
        return rc;

    rc = nfc_llcp_register_device(dev);
    if (rc)
        pr_err("Could not register llcp device\n");

    rc = nfc_genl_device_added(dev);
    if (rc)
        pr_debug("The userspace won't be notified that the device %s was added\n",
             dev_name(&dev->dev));

    return 0;
}
EXPORT_SYMBOL(nfc_register_device);

void nfc_unregister_device(struct nfc_dev *dev)
{
    int rc;

    pr_debug("dev_name=%s\n", dev_name(&dev->dev));

    mutex_lock(&nfc_devlist_mutex);
    nfc_devlist_generation++;

    /* lock to avoid unregistering a device while an operation
       is in progress */
    device_lock(&dev->dev);
    device_del(&dev->dev);
    device_unlock(&dev->dev);

    mutex_unlock(&nfc_devlist_mutex);

    nfc_llcp_unregister_device(dev);

    rc = nfc_genl_device_removed(dev);
    if (rc)
        pr_debug("The userspace won't be notified that the device %s was removed\n",
             dev_name(&dev->dev));

}
EXPORT_SYMBOL(nfc_unregister_device);

static int __init nfc_init(void)
{
    int rc;

    pr_info("NFC Core ver %s\n", VERSION);

    rc = class_register(&nfc_class);
    if (rc)
        return rc;

    rc = nfc_genl_init();
    if (rc)
        goto err_genl;

    /* the first generation must not be 0 */
    nfc_devlist_generation = 1;

    rc = rawsock_init();
    if (rc)
        goto err_rawsock;

    rc = nfc_llcp_init();
    if (rc)
        goto err_llcp_sock;

    rc = af_nfc_init();
    if (rc)
        goto err_af_nfc;

    return 0;

err_af_nfc:
    nfc_llcp_exit();
err_llcp_sock:
    rawsock_exit();
err_rawsock:
    nfc_genl_exit();
err_genl:
    class_unregister(&nfc_class);
    return rc;
}

static void __exit nfc_exit(void)
{
    af_nfc_exit();
    nfc_llcp_exit();
    rawsock_exit();
    nfc_genl_exit();
    class_unregister(&nfc_class);
}

subsys_initcall(nfc_init);
module_exit(nfc_exit);

MODULE_AUTHOR("Lauro Ramos Venancio <[email protected]>");
MODULE_DESCRIPTION("NFC Core ver " VERSION);
MODULE_VERSION(VERSION);
MODULE_LICENSE("GPL");
MODULE_ALIAS_NETPROTO(PF_NFC);
MODULE_ALIAS_GENL_FAMILY(NFC_GENL_NAME);