- 根目录:
- drivers
- nfc
- nfcsim.c
/*
* NFC hardware simulation driver
* 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.
*
*/
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/nfc.h>
#include <net/nfc/nfc.h>
#define DEV_ERR(_dev, fmt, args...) nfc_err(&_dev->nfc_dev->dev, \
"%s: " fmt, __func__, ## args)
#define DEV_DBG(_dev, fmt, args...) dev_dbg(&_dev->nfc_dev->dev, \
"%s: " fmt, __func__, ## args)
#define NFCSIM_VERSION "0.1"
#define NFCSIM_POLL_NONE 0
#define NFCSIM_POLL_INITIATOR 1
#define NFCSIM_POLL_TARGET 2
#define NFCSIM_POLL_DUAL (NFCSIM_POLL_INITIATOR | NFCSIM_POLL_TARGET)
struct nfcsim {
struct nfc_dev *nfc_dev;
struct mutex lock;
struct delayed_work recv_work;
struct sk_buff *clone_skb;
struct delayed_work poll_work;
u8 polling_mode;
u8 curr_polling_mode;
u8 shutting_down;
u8 up;
u8 initiator;
data_exchange_cb_t cb;
void *cb_context;
struct nfcsim *peer_dev;
};
static struct nfcsim *dev0;
static struct nfcsim *dev1;
static struct workqueue_struct *wq;
static void nfcsim_cleanup_dev(struct nfcsim *dev, u8 shutdown)
{
DEV_DBG(dev, "shutdown=%d\n", shutdown);
mutex_lock(&dev->lock);
dev->polling_mode = NFCSIM_POLL_NONE;
dev->shutting_down = shutdown;
dev->cb = NULL;
dev_kfree_skb(dev->clone_skb);
dev->clone_skb = NULL;
mutex_unlock(&dev->lock);
cancel_delayed_work_sync(&dev->poll_work);
cancel_delayed_work_sync(&dev->recv_work);
}
static int nfcsim_target_found(struct nfcsim *dev)
{
struct nfc_target nfc_tgt;
DEV_DBG(dev, "\n");
memset(&nfc_tgt, 0, sizeof(struct nfc_target));
nfc_tgt.supported_protocols = NFC_PROTO_NFC_DEP_MASK;
nfc_targets_found(dev->nfc_dev, &nfc_tgt, 1);
return 0;
}
static int nfcsim_dev_up(struct nfc_dev *nfc_dev)
{
struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
DEV_DBG(dev, "\n");
mutex_lock(&dev->lock);
dev->up = 1;
mutex_unlock(&dev->lock);
return 0;
}
static int nfcsim_dev_down(struct nfc_dev *nfc_dev)
{
struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
DEV_DBG(dev, "\n");
mutex_lock(&dev->lock);
dev->up = 0;
mutex_unlock(&dev->lock);
return 0;
}
static int nfcsim_dep_link_up(struct nfc_dev *nfc_dev,
struct nfc_target *target,
u8 comm_mode, u8 *gb, size_t gb_len)
{
int rc;
struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
struct nfcsim *peer = dev->peer_dev;
u8 *remote_gb;
size_t remote_gb_len;
DEV_DBG(dev, "target_idx: %d, comm_mode: %d\n", target->idx, comm_mode);
mutex_lock(&peer->lock);
nfc_tm_activated(peer->nfc_dev, NFC_PROTO_NFC_DEP_MASK,
NFC_COMM_ACTIVE, gb, gb_len);
remote_gb = nfc_get_local_general_bytes(peer->nfc_dev, &remote_gb_len);
if (!remote_gb) {
DEV_ERR(peer, "Can't get remote general bytes\n");
mutex_unlock(&peer->lock);
return -EINVAL;
}
mutex_unlock(&peer->lock);
mutex_lock(&dev->lock);
rc = nfc_set_remote_general_bytes(nfc_dev, remote_gb, remote_gb_len);
if (rc) {
DEV_ERR(dev, "Can't set remote general bytes\n");
mutex_unlock(&dev->lock);
return rc;
}
rc = nfc_dep_link_is_up(nfc_dev, target->idx, NFC_COMM_ACTIVE,
NFC_RF_INITIATOR);
mutex_unlock(&dev->lock);
return rc;
}
static int nfcsim_dep_link_down(struct nfc_dev *nfc_dev)
{
struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
DEV_DBG(dev, "\n");
nfcsim_cleanup_dev(dev, 0);
return 0;
}
static int nfcsim_start_poll(struct nfc_dev *nfc_dev,
u32 im_protocols, u32 tm_protocols)
{
struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
int rc;
mutex_lock(&dev->lock);
if (dev->polling_mode != NFCSIM_POLL_NONE) {
DEV_ERR(dev, "Already in polling mode\n");
rc = -EBUSY;
goto exit;
}
if (im_protocols & NFC_PROTO_NFC_DEP_MASK)
dev->polling_mode |= NFCSIM_POLL_INITIATOR;
if (tm_protocols & NFC_PROTO_NFC_DEP_MASK)
dev->polling_mode |= NFCSIM_POLL_TARGET;
if (dev->polling_mode == NFCSIM_POLL_NONE) {
DEV_ERR(dev, "Unsupported polling mode\n");
rc = -EINVAL;
goto exit;
}
dev->initiator = 0;
dev->curr_polling_mode = NFCSIM_POLL_NONE;
queue_delayed_work(wq, &dev->poll_work, 0);
DEV_DBG(dev, "Start polling: im: 0x%X, tm: 0x%X\n", im_protocols,
tm_protocols);
rc = 0;
exit:
mutex_unlock(&dev->lock);
return rc;
}
static void nfcsim_stop_poll(struct nfc_dev *nfc_dev)
{
struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
DEV_DBG(dev, "Stop poll\n");
mutex_lock(&dev->lock);
dev->polling_mode = NFCSIM_POLL_NONE;
mutex_unlock(&dev->lock);
cancel_delayed_work_sync(&dev->poll_work);
}
static int nfcsim_activate_target(struct nfc_dev *nfc_dev,
struct nfc_target *target, u32 protocol)
{
struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
DEV_DBG(dev, "\n");
return -ENOTSUPP;
}
static void nfcsim_deactivate_target(struct nfc_dev *nfc_dev,
struct nfc_target *target)
{
struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
DEV_DBG(dev, "\n");
}
static void nfcsim_wq_recv(struct work_struct *work)
{
struct nfcsim *dev = container_of(work, struct nfcsim,
recv_work.work);
mutex_lock(&dev->lock);
if (dev->shutting_down || !dev->up || !dev->clone_skb) {
dev_kfree_skb(dev->clone_skb);
goto exit;
}
if (dev->initiator) {
if (!dev->cb) {
DEV_ERR(dev, "Null recv callback\n");
dev_kfree_skb(dev->clone_skb);
goto exit;
}
dev->cb(dev->cb_context, dev->clone_skb, 0);
dev->cb = NULL;
} else {
nfc_tm_data_received(dev->nfc_dev, dev->clone_skb);
}
exit:
dev->clone_skb = NULL;
mutex_unlock(&dev->lock);
}
static int nfcsim_tx(struct nfc_dev *nfc_dev, struct nfc_target *target,
struct sk_buff *skb, data_exchange_cb_t cb,
void *cb_context)
{
struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
struct nfcsim *peer = dev->peer_dev;
int err;
mutex_lock(&dev->lock);
if (dev->shutting_down || !dev->up) {
mutex_unlock(&dev->lock);
err = -ENODEV;
goto exit;
}
dev->cb = cb;
dev->cb_context = cb_context;
mutex_unlock(&dev->lock);
mutex_lock(&peer->lock);
peer->clone_skb = skb_clone(skb, GFP_KERNEL);
if (!peer->clone_skb) {
DEV_ERR(dev, "skb_clone failed\n");
mutex_unlock(&peer->lock);
err = -ENOMEM;
goto exit;
}
/* This simulates an arbitrary transmission delay between the 2 devices.
* If packet transmission occurs immediately between them, we have a
* non-stop flow of several tens of thousands SYMM packets per second
* and a burning cpu.
*
* TODO: Add support for a sysfs entry to control this delay.
*/
queue_delayed_work(wq, &peer->recv_work, msecs_to_jiffies(5));
mutex_unlock(&peer->lock);
err = 0;
exit:
dev_kfree_skb(skb);
return err;
}
static int nfcsim_im_transceive(struct nfc_dev *nfc_dev,
struct nfc_target *target, struct sk_buff *skb,
data_exchange_cb_t cb, void *cb_context)
{
return nfcsim_tx(nfc_dev, target, skb, cb, cb_context);
}
static int nfcsim_tm_send(struct nfc_dev *nfc_dev, struct sk_buff *skb)
{
return nfcsim_tx(nfc_dev, NULL, skb, NULL, NULL);
}
static struct nfc_ops nfcsim_nfc_ops = {
.dev_up = nfcsim_dev_up,
.dev_down = nfcsim_dev_down,
.dep_link_up = nfcsim_dep_link_up,
.dep_link_down = nfcsim_dep_link_down,
.start_poll = nfcsim_start_poll,
.stop_poll = nfcsim_stop_poll,
.activate_target = nfcsim_activate_target,
.deactivate_target = nfcsim_deactivate_target,
.im_transceive = nfcsim_im_transceive,
.tm_send = nfcsim_tm_send,
};
static void nfcsim_set_polling_mode(struct nfcsim *dev)
{
if (dev->polling_mode == NFCSIM_POLL_NONE) {
dev->curr_polling_mode = NFCSIM_POLL_NONE;
return;
}
if (dev->curr_polling_mode == NFCSIM_POLL_NONE) {
if (dev->polling_mode & NFCSIM_POLL_INITIATOR)
dev->curr_polling_mode = NFCSIM_POLL_INITIATOR;
else
dev->curr_polling_mode = NFCSIM_POLL_TARGET;
return;
}
if (dev->polling_mode == NFCSIM_POLL_DUAL) {
if (dev->curr_polling_mode == NFCSIM_POLL_TARGET)
dev->curr_polling_mode = NFCSIM_POLL_INITIATOR;
else
dev->curr_polling_mode = NFCSIM_POLL_TARGET;
}
}
static void nfcsim_wq_poll(struct work_struct *work)
{
struct nfcsim *dev = container_of(work, struct nfcsim, poll_work.work);
struct nfcsim *peer = dev->peer_dev;
/* These work items run on an ordered workqueue and are therefore
* serialized. So we can take both mutexes without being dead locked.
*/
mutex_lock(&dev->lock);
mutex_lock(&peer->lock);
nfcsim_set_polling_mode(dev);
if (dev->curr_polling_mode == NFCSIM_POLL_NONE) {
DEV_DBG(dev, "Not polling\n");
goto unlock;
}
DEV_DBG(dev, "Polling as %s",
dev->curr_polling_mode == NFCSIM_POLL_INITIATOR ?
"initiator\n" : "target\n");
if (dev->curr_polling_mode == NFCSIM_POLL_TARGET)
goto sched_work;
if (peer->curr_polling_mode == NFCSIM_POLL_TARGET) {
peer->polling_mode = NFCSIM_POLL_NONE;
dev->polling_mode = NFCSIM_POLL_NONE;
dev->initiator = 1;
nfcsim_target_found(dev);
goto unlock;
}
sched_work:
/* This defines the delay for an initiator to check if the other device
* is polling in target mode.
* If the device starts in dual mode polling, it switches between
* initiator and target at every round.
* Because the wq is ordered and only 1 work item is executed at a time,
* we'll always have one device polling as initiator and the other as
* target at some point, even if both are started in dual mode.
*/
queue_delayed_work(wq, &dev->poll_work, msecs_to_jiffies(200));
unlock:
mutex_unlock(&peer->lock);
mutex_unlock(&dev->lock);
}
static struct nfcsim *nfcsim_init_dev(void)
{
struct nfcsim *dev;
int rc = -ENOMEM;
dev = kzalloc(sizeof(*dev), GFP_KERNEL);
if (dev == NULL)
return ERR_PTR(-ENOMEM);
mutex_init(&dev->lock);
INIT_DELAYED_WORK(&dev->recv_work, nfcsim_wq_recv);
INIT_DELAYED_WORK(&dev->poll_work, nfcsim_wq_poll);
dev->nfc_dev = nfc_allocate_device(&nfcsim_nfc_ops,
NFC_PROTO_NFC_DEP_MASK,
0, 0);
if (!dev->nfc_dev)
goto error;
nfc_set_drvdata(dev->nfc_dev, dev);
rc = nfc_register_device(dev->nfc_dev);
if (rc)
goto free_nfc_dev;
return dev;
free_nfc_dev:
nfc_free_device(dev->nfc_dev);
error:
kfree(dev);
return ERR_PTR(rc);
}
static void nfcsim_free_device(struct nfcsim *dev)
{
nfc_unregister_device(dev->nfc_dev);
nfc_free_device(dev->nfc_dev);
kfree(dev);
}
static int __init nfcsim_init(void)
{
int rc;
/* We need an ordered wq to ensure that poll_work items are executed
* one at a time.
*/
wq = alloc_ordered_workqueue("nfcsim", 0);
if (!wq) {
rc = -ENOMEM;
goto exit;
}
dev0 = nfcsim_init_dev();
if (IS_ERR(dev0)) {
rc = PTR_ERR(dev0);
goto exit;
}
dev1 = nfcsim_init_dev();
if (IS_ERR(dev1)) {
kfree(dev0);
rc = PTR_ERR(dev1);
goto exit;
}
dev0->peer_dev = dev1;
dev1->peer_dev = dev0;
pr_debug("NFCsim " NFCSIM_VERSION " initialized\n");
rc = 0;
exit:
if (rc)
pr_err("Failed to initialize nfcsim driver (%d)\n",
rc);
return rc;
}
static void __exit nfcsim_exit(void)
{
nfcsim_cleanup_dev(dev0, 1);
nfcsim_cleanup_dev(dev1, 1);
nfcsim_free_device(dev0);
nfcsim_free_device(dev1);
destroy_workqueue(wq);
}
module_init(nfcsim_init);
module_exit(nfcsim_exit);
MODULE_DESCRIPTION("NFCSim driver ver " NFCSIM_VERSION);
MODULE_VERSION(NFCSIM_VERSION);
MODULE_LICENSE("GPL");