496 lines
9.8 KiB
C
496 lines
9.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* NFC hardware simulation driver
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* Copyright (c) 2013, Intel Corporation.
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*/
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#include <linux/device.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/ctype.h>
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#include <linux/debugfs.h>
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#include <linux/nfc.h>
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#include <net/nfc/nfc.h>
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#include <net/nfc/digital.h>
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#define NFCSIM_ERR(d, fmt, args...) nfc_err(&d->nfc_digital_dev->nfc_dev->dev, \
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"%s: " fmt, __func__, ## args)
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#define NFCSIM_DBG(d, fmt, args...) dev_dbg(&d->nfc_digital_dev->nfc_dev->dev, \
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"%s: " fmt, __func__, ## args)
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#define NFCSIM_VERSION "0.2"
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#define NFCSIM_MODE_NONE 0
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#define NFCSIM_MODE_INITIATOR 1
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#define NFCSIM_MODE_TARGET 2
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#define NFCSIM_CAPABILITIES (NFC_DIGITAL_DRV_CAPS_IN_CRC | \
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NFC_DIGITAL_DRV_CAPS_TG_CRC)
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struct nfcsim {
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struct nfc_digital_dev *nfc_digital_dev;
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struct work_struct recv_work;
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struct delayed_work send_work;
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struct nfcsim_link *link_in;
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struct nfcsim_link *link_out;
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bool up;
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u8 mode;
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u8 rf_tech;
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u16 recv_timeout;
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nfc_digital_cmd_complete_t cb;
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void *arg;
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u8 dropframe;
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};
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struct nfcsim_link {
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struct mutex lock;
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u8 rf_tech;
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u8 mode;
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u8 shutdown;
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struct sk_buff *skb;
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wait_queue_head_t recv_wait;
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u8 cond;
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};
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static struct nfcsim_link *nfcsim_link_new(void)
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{
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struct nfcsim_link *link;
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link = kzalloc(sizeof(struct nfcsim_link), GFP_KERNEL);
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if (!link)
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return NULL;
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mutex_init(&link->lock);
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init_waitqueue_head(&link->recv_wait);
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return link;
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}
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static void nfcsim_link_free(struct nfcsim_link *link)
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{
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dev_kfree_skb(link->skb);
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kfree(link);
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}
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static void nfcsim_link_recv_wake(struct nfcsim_link *link)
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{
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link->cond = 1;
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wake_up_interruptible(&link->recv_wait);
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}
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static void nfcsim_link_set_skb(struct nfcsim_link *link, struct sk_buff *skb,
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u8 rf_tech, u8 mode)
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{
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mutex_lock(&link->lock);
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dev_kfree_skb(link->skb);
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link->skb = skb;
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link->rf_tech = rf_tech;
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link->mode = mode;
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mutex_unlock(&link->lock);
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}
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static void nfcsim_link_recv_cancel(struct nfcsim_link *link)
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{
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mutex_lock(&link->lock);
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link->mode = NFCSIM_MODE_NONE;
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mutex_unlock(&link->lock);
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nfcsim_link_recv_wake(link);
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}
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static void nfcsim_link_shutdown(struct nfcsim_link *link)
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{
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mutex_lock(&link->lock);
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link->shutdown = 1;
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link->mode = NFCSIM_MODE_NONE;
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mutex_unlock(&link->lock);
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nfcsim_link_recv_wake(link);
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}
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static struct sk_buff *nfcsim_link_recv_skb(struct nfcsim_link *link,
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int timeout, u8 rf_tech, u8 mode)
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{
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int rc;
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struct sk_buff *skb;
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rc = wait_event_interruptible_timeout(link->recv_wait,
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link->cond,
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msecs_to_jiffies(timeout));
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mutex_lock(&link->lock);
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skb = link->skb;
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link->skb = NULL;
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if (!rc) {
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rc = -ETIMEDOUT;
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goto done;
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}
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if (!skb || link->rf_tech != rf_tech || link->mode == mode) {
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rc = -EINVAL;
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goto done;
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}
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if (link->shutdown) {
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rc = -ENODEV;
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goto done;
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}
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done:
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mutex_unlock(&link->lock);
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if (rc < 0) {
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dev_kfree_skb(skb);
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skb = ERR_PTR(rc);
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}
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link->cond = 0;
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return skb;
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}
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static void nfcsim_send_wq(struct work_struct *work)
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{
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struct nfcsim *dev = container_of(work, struct nfcsim, send_work.work);
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/*
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* To effectively send data, the device just wake up its link_out which
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* is the link_in of the peer device. The exchanged skb has already been
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* stored in the dev->link_out through nfcsim_link_set_skb().
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*/
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nfcsim_link_recv_wake(dev->link_out);
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}
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static void nfcsim_recv_wq(struct work_struct *work)
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{
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struct nfcsim *dev = container_of(work, struct nfcsim, recv_work);
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struct sk_buff *skb;
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skb = nfcsim_link_recv_skb(dev->link_in, dev->recv_timeout,
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dev->rf_tech, dev->mode);
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if (!dev->up) {
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NFCSIM_ERR(dev, "Device is down\n");
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if (!IS_ERR(skb))
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dev_kfree_skb(skb);
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return;
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}
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dev->cb(dev->nfc_digital_dev, dev->arg, skb);
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}
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static int nfcsim_send(struct nfc_digital_dev *ddev, struct sk_buff *skb,
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u16 timeout, nfc_digital_cmd_complete_t cb, void *arg)
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{
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struct nfcsim *dev = nfc_digital_get_drvdata(ddev);
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u8 delay;
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if (!dev->up) {
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NFCSIM_ERR(dev, "Device is down\n");
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return -ENODEV;
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}
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dev->recv_timeout = timeout;
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dev->cb = cb;
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dev->arg = arg;
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schedule_work(&dev->recv_work);
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if (dev->dropframe) {
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NFCSIM_DBG(dev, "dropping frame (out of %d)\n", dev->dropframe);
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dev_kfree_skb(skb);
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dev->dropframe--;
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return 0;
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}
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if (skb) {
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nfcsim_link_set_skb(dev->link_out, skb, dev->rf_tech,
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dev->mode);
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/* Add random delay (between 3 and 10 ms) before sending data */
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get_random_bytes(&delay, 1);
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delay = 3 + (delay & 0x07);
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schedule_delayed_work(&dev->send_work, msecs_to_jiffies(delay));
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}
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return 0;
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}
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static void nfcsim_abort_cmd(struct nfc_digital_dev *ddev)
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{
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const struct nfcsim *dev = nfc_digital_get_drvdata(ddev);
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nfcsim_link_recv_cancel(dev->link_in);
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}
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static int nfcsim_switch_rf(struct nfc_digital_dev *ddev, bool on)
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{
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struct nfcsim *dev = nfc_digital_get_drvdata(ddev);
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dev->up = on;
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return 0;
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}
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static int nfcsim_in_configure_hw(struct nfc_digital_dev *ddev,
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int type, int param)
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{
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struct nfcsim *dev = nfc_digital_get_drvdata(ddev);
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switch (type) {
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case NFC_DIGITAL_CONFIG_RF_TECH:
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dev->up = true;
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dev->mode = NFCSIM_MODE_INITIATOR;
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dev->rf_tech = param;
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break;
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case NFC_DIGITAL_CONFIG_FRAMING:
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break;
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default:
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NFCSIM_ERR(dev, "Invalid configuration type: %d\n", type);
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return -EINVAL;
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}
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return 0;
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}
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static int nfcsim_in_send_cmd(struct nfc_digital_dev *ddev,
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struct sk_buff *skb, u16 timeout,
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nfc_digital_cmd_complete_t cb, void *arg)
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{
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return nfcsim_send(ddev, skb, timeout, cb, arg);
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}
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static int nfcsim_tg_configure_hw(struct nfc_digital_dev *ddev,
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int type, int param)
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{
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struct nfcsim *dev = nfc_digital_get_drvdata(ddev);
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switch (type) {
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case NFC_DIGITAL_CONFIG_RF_TECH:
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dev->up = true;
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dev->mode = NFCSIM_MODE_TARGET;
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dev->rf_tech = param;
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break;
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case NFC_DIGITAL_CONFIG_FRAMING:
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break;
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default:
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NFCSIM_ERR(dev, "Invalid configuration type: %d\n", type);
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return -EINVAL;
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}
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return 0;
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}
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static int nfcsim_tg_send_cmd(struct nfc_digital_dev *ddev,
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struct sk_buff *skb, u16 timeout,
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nfc_digital_cmd_complete_t cb, void *arg)
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{
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return nfcsim_send(ddev, skb, timeout, cb, arg);
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}
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static int nfcsim_tg_listen(struct nfc_digital_dev *ddev, u16 timeout,
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nfc_digital_cmd_complete_t cb, void *arg)
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{
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return nfcsim_send(ddev, NULL, timeout, cb, arg);
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}
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static const struct nfc_digital_ops nfcsim_digital_ops = {
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.in_configure_hw = nfcsim_in_configure_hw,
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.in_send_cmd = nfcsim_in_send_cmd,
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.tg_listen = nfcsim_tg_listen,
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.tg_configure_hw = nfcsim_tg_configure_hw,
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.tg_send_cmd = nfcsim_tg_send_cmd,
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.abort_cmd = nfcsim_abort_cmd,
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.switch_rf = nfcsim_switch_rf,
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};
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static struct dentry *nfcsim_debugfs_root;
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static void nfcsim_debugfs_init(void)
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{
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nfcsim_debugfs_root = debugfs_create_dir("nfcsim", NULL);
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}
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static void nfcsim_debugfs_remove(void)
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{
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debugfs_remove_recursive(nfcsim_debugfs_root);
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}
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static void nfcsim_debugfs_init_dev(struct nfcsim *dev)
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{
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struct dentry *dev_dir;
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char devname[5]; /* nfcX\0 */
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u32 idx;
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int n;
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if (!nfcsim_debugfs_root) {
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NFCSIM_ERR(dev, "nfcsim debugfs not initialized\n");
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return;
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}
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idx = dev->nfc_digital_dev->nfc_dev->idx;
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n = snprintf(devname, sizeof(devname), "nfc%d", idx);
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if (n >= sizeof(devname)) {
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NFCSIM_ERR(dev, "Could not compute dev name for dev %d\n", idx);
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return;
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}
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dev_dir = debugfs_create_dir(devname, nfcsim_debugfs_root);
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debugfs_create_u8("dropframe", 0664, dev_dir, &dev->dropframe);
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}
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static struct nfcsim *nfcsim_device_new(struct nfcsim_link *link_in,
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struct nfcsim_link *link_out)
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{
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struct nfcsim *dev;
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int rc;
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dev = kzalloc(sizeof(struct nfcsim), GFP_KERNEL);
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if (!dev)
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return ERR_PTR(-ENOMEM);
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INIT_DELAYED_WORK(&dev->send_work, nfcsim_send_wq);
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INIT_WORK(&dev->recv_work, nfcsim_recv_wq);
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dev->nfc_digital_dev =
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nfc_digital_allocate_device(&nfcsim_digital_ops,
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NFC_PROTO_NFC_DEP_MASK,
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NFCSIM_CAPABILITIES,
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0, 0);
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if (!dev->nfc_digital_dev) {
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kfree(dev);
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return ERR_PTR(-ENOMEM);
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}
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nfc_digital_set_drvdata(dev->nfc_digital_dev, dev);
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dev->link_in = link_in;
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dev->link_out = link_out;
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rc = nfc_digital_register_device(dev->nfc_digital_dev);
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if (rc) {
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pr_err("Could not register digital device (%d)\n", rc);
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nfc_digital_free_device(dev->nfc_digital_dev);
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kfree(dev);
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return ERR_PTR(rc);
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}
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nfcsim_debugfs_init_dev(dev);
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return dev;
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}
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static void nfcsim_device_free(struct nfcsim *dev)
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{
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nfc_digital_unregister_device(dev->nfc_digital_dev);
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dev->up = false;
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nfcsim_link_shutdown(dev->link_in);
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cancel_delayed_work_sync(&dev->send_work);
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cancel_work_sync(&dev->recv_work);
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nfc_digital_free_device(dev->nfc_digital_dev);
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kfree(dev);
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}
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static struct nfcsim *dev0;
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static struct nfcsim *dev1;
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static int __init nfcsim_init(void)
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{
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struct nfcsim_link *link0, *link1;
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int rc;
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link0 = nfcsim_link_new();
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link1 = nfcsim_link_new();
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if (!link0 || !link1) {
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rc = -ENOMEM;
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goto exit_err;
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}
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nfcsim_debugfs_init();
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dev0 = nfcsim_device_new(link0, link1);
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if (IS_ERR(dev0)) {
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rc = PTR_ERR(dev0);
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goto exit_err;
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}
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dev1 = nfcsim_device_new(link1, link0);
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if (IS_ERR(dev1)) {
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nfcsim_device_free(dev0);
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rc = PTR_ERR(dev1);
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goto exit_err;
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}
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pr_info("nfcsim " NFCSIM_VERSION " initialized\n");
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return 0;
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exit_err:
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pr_err("Failed to initialize nfcsim driver (%d)\n", rc);
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if (link0)
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nfcsim_link_free(link0);
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if (link1)
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nfcsim_link_free(link1);
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return rc;
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}
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static void __exit nfcsim_exit(void)
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{
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struct nfcsim_link *link0, *link1;
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link0 = dev0->link_in;
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link1 = dev0->link_out;
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nfcsim_device_free(dev0);
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nfcsim_device_free(dev1);
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nfcsim_link_free(link0);
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nfcsim_link_free(link1);
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nfcsim_debugfs_remove();
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}
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module_init(nfcsim_init);
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module_exit(nfcsim_exit);
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MODULE_DESCRIPTION("NFCSim driver ver " NFCSIM_VERSION);
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MODULE_VERSION(NFCSIM_VERSION);
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MODULE_LICENSE("GPL");
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