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/*
* 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/ctype.h>
#include <linux/debugfs.h>
#include <linux/nfc.h>
#include <net/nfc/nfc.h>
#include <net/nfc/digital.h>
#define NFCSIM_ERR(d, fmt, args...) nfc_err(&d->nfc_digital_dev->nfc_dev->dev, \
"%s: " fmt, __func__, ## args)
#define NFCSIM_DBG(d, fmt, args...) dev_dbg(&d->nfc_digital_dev->nfc_dev->dev, \
"%s: " fmt, __func__, ## args)
#define NFCSIM_VERSION "0.2"
#define NFCSIM_MODE_NONE 0
#define NFCSIM_MODE_INITIATOR 1
#define NFCSIM_MODE_TARGET 2
#define NFCSIM_CAPABILITIES (NFC_DIGITAL_DRV_CAPS_IN_CRC | \
NFC_DIGITAL_DRV_CAPS_TG_CRC)
struct nfcsim {
struct nfc_digital_dev *nfc_digital_dev;
struct work_struct recv_work;
struct delayed_work send_work;
struct nfcsim_link *link_in;
struct nfcsim_link *link_out;
bool up;
u8 mode;
u8 rf_tech;
u16 recv_timeout;
nfc_digital_cmd_complete_t cb;
void *arg;
};
struct nfcsim_link {
struct mutex lock;
u8 rf_tech;
u8 mode;
u8 shutdown;
struct sk_buff *skb;
wait_queue_head_t recv_wait;
u8 cond;
};
static struct nfcsim_link *nfcsim_link_new(void)
{
struct nfcsim_link *link;
link = kzalloc(sizeof(struct nfcsim_link), GFP_KERNEL);
if (!link)
return NULL;
mutex_init(&link->lock);
init_waitqueue_head(&link->recv_wait);
return link;
}
static void nfcsim_link_free(struct nfcsim_link *link)
{
dev_kfree_skb(link->skb);
kfree(link);
}
static void nfcsim_link_recv_wake(struct nfcsim_link *link)
{
link->cond = 1;
wake_up_interruptible(&link->recv_wait);
}
static void nfcsim_link_set_skb(struct nfcsim_link *link, struct sk_buff *skb,
u8 rf_tech, u8 mode)
{
mutex_lock(&link->lock);
dev_kfree_skb(link->skb);
link->skb = skb;
link->rf_tech = rf_tech;
link->mode = mode;
mutex_unlock(&link->lock);
}
static void nfcsim_link_recv_cancel(struct nfcsim_link *link)
{
mutex_lock(&link->lock);
link->mode = NFCSIM_MODE_NONE;
mutex_unlock(&link->lock);
nfcsim_link_recv_wake(link);
}
static void nfcsim_link_shutdown(struct nfcsim_link *link)
{
mutex_lock(&link->lock);
link->shutdown = 1;
link->mode = NFCSIM_MODE_NONE;
mutex_unlock(&link->lock);
nfcsim_link_recv_wake(link);
}
static struct sk_buff *nfcsim_link_recv_skb(struct nfcsim_link *link,
int timeout, u8 rf_tech, u8 mode)
{
int rc;
struct sk_buff *skb;
rc = wait_event_interruptible_timeout(link->recv_wait,
link->cond,
msecs_to_jiffies(timeout));
mutex_lock(&link->lock);
skb = link->skb;
link->skb = NULL;
if (!rc) {
rc = -ETIMEDOUT;
goto done;
}
if (!skb || link->rf_tech != rf_tech || link->mode == mode) {
rc = -EINVAL;
goto done;
}
if (link->shutdown) {
rc = -ENODEV;
goto done;
}
done:
mutex_unlock(&link->lock);
if (rc < 0) {
dev_kfree_skb(skb);
skb = ERR_PTR(rc);
}
link->cond = 0;
return skb;
}
static void nfcsim_send_wq(struct work_struct *work)
{
struct nfcsim *dev = container_of(work, struct nfcsim, send_work.work);
/*
* To effectively send data, the device just wake up its link_out which
* is the link_in of the peer device. The exchanged skb has already been
* stored in the dev->link_out through nfcsim_link_set_skb().
*/
nfcsim_link_recv_wake(dev->link_out);
}
static void nfcsim_recv_wq(struct work_struct *work)
{
struct nfcsim *dev = container_of(work, struct nfcsim, recv_work);
struct sk_buff *skb;
skb = nfcsim_link_recv_skb(dev->link_in, dev->recv_timeout,
dev->rf_tech, dev->mode);
if (!dev->up) {
NFCSIM_ERR(dev, "Device is down\n");
if (!IS_ERR(skb))
dev_kfree_skb(skb);
skb = ERR_PTR(-ENODEV);
}
dev->cb(dev->nfc_digital_dev, dev->arg, skb);
}
static int nfcsim_send(struct nfc_digital_dev *ddev, struct sk_buff *skb,
u16 timeout, nfc_digital_cmd_complete_t cb, void *arg)
{
struct nfcsim *dev = nfc_digital_get_drvdata(ddev);
u8 delay;
if (!dev->up) {
NFCSIM_ERR(dev, "Device is down\n");
return -ENODEV;
}
dev->recv_timeout = timeout;
dev->cb = cb;
dev->arg = arg;
schedule_work(&dev->recv_work);
if (skb) {
nfcsim_link_set_skb(dev->link_out, skb, dev->rf_tech,
dev->mode);
/* Add random delay (between 3 and 10 ms) before sending data */
get_random_bytes(&delay, 1);
delay = 3 + (delay & 0x07);
schedule_delayed_work(&dev->send_work, msecs_to_jiffies(delay));
}
return 0;
}
static void nfcsim_abort_cmd(struct nfc_digital_dev *ddev)
{
struct nfcsim *dev = nfc_digital_get_drvdata(ddev);
nfcsim_link_recv_cancel(dev->link_in);
}
static int nfcsim_switch_rf(struct nfc_digital_dev *ddev, bool on)
{
struct nfcsim *dev = nfc_digital_get_drvdata(ddev);
dev->up = on;
return 0;
}
static int nfcsim_in_configure_hw(struct nfc_digital_dev *ddev,
int type, int param)
{
struct nfcsim *dev = nfc_digital_get_drvdata(ddev);
switch (type) {
case NFC_DIGITAL_CONFIG_RF_TECH:
dev->up = true;
dev->mode = NFCSIM_MODE_INITIATOR;
dev->rf_tech = param;
break;
case NFC_DIGITAL_CONFIG_FRAMING:
break;
default:
NFCSIM_ERR(dev, "Invalid configuration type: %d\n", type);
return -EINVAL;
}
return 0;
}
static int nfcsim_in_send_cmd(struct nfc_digital_dev *ddev,
struct sk_buff *skb, u16 timeout,
nfc_digital_cmd_complete_t cb, void *arg)
{
return nfcsim_send(ddev, skb, timeout, cb, arg);
}
static int nfcsim_tg_configure_hw(struct nfc_digital_dev *ddev,
int type, int param)
{
struct nfcsim *dev = nfc_digital_get_drvdata(ddev);
switch (type) {
case NFC_DIGITAL_CONFIG_RF_TECH:
dev->up = true;
dev->mode = NFCSIM_MODE_TARGET;
dev->rf_tech = param;
break;
case NFC_DIGITAL_CONFIG_FRAMING:
break;
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