1 files changed, 495 insertions, 0 deletions

diff --git a/drivers/nfc/nfcsim.c b/drivers/nfc/nfcsim.c
new file mode 100644
index 0000000000..a55381f80c
--- /dev/null
+++ b/drivers/nfc/nfcsim.c
@@ -0,0 +1,495 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * NFC hardware simulation driver
+ * Copyright (c) 2013, Intel Corporation.
+ */
+
+#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;
+
+	u8 dropframe;
+};
+
+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);
+		return;
+	}
+
+	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 (dev->dropframe) {
+		NFCSIM_DBG(dev, "dropping frame (out of %d)\n", dev->dropframe);
+		dev_kfree_skb(skb);
+		dev->dropframe--;
+
+		return 0;
+	}
+
+	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)
+{
+	const 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;
+
+	default:
+		NFCSIM_ERR(dev, "Invalid configuration type: %d\n", type);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int nfcsim_tg_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_listen(struct nfc_digital_dev *ddev, u16 timeout,
+			    nfc_digital_cmd_complete_t cb, void *arg)
+{
+	return nfcsim_send(ddev, NULL, timeout, cb, arg);
+}
+
+static const struct nfc_digital_ops nfcsim_digital_ops = {
+	.in_configure_hw = nfcsim_in_configure_hw,
+	.in_send_cmd = nfcsim_in_send_cmd,
+
+	.tg_listen = nfcsim_tg_listen,
+	.tg_configure_hw = nfcsim_tg_configure_hw,
+	.tg_send_cmd = nfcsim_tg_send_cmd,
+
+	.abort_cmd = nfcsim_abort_cmd,
+	.switch_rf = nfcsim_switch_rf,
+};
+
+static struct dentry *nfcsim_debugfs_root;
+
+static void nfcsim_debugfs_init(void)
+{
+	nfcsim_debugfs_root = debugfs_create_dir("nfcsim", NULL);
+}
+
+static void nfcsim_debugfs_remove(void)
+{
+	debugfs_remove_recursive(nfcsim_debugfs_root);
+}
+
+static void nfcsim_debugfs_init_dev(struct nfcsim *dev)
+{
+	struct dentry *dev_dir;
+	char devname[5]; /* nfcX\0 */
+	u32 idx;
+	int n;
+
+	if (!nfcsim_debugfs_root) {
+		NFCSIM_ERR(dev, "nfcsim debugfs not initialized\n");
+		return;
+	}
+
+	idx = dev->nfc_digital_dev->nfc_dev->idx;
+	n = snprintf(devname, sizeof(devname), "nfc%d", idx);
+	if (n >= sizeof(devname)) {
+		NFCSIM_ERR(dev, "Could not compute dev name for dev %d\n", idx);
+		return;
+	}
+
+	dev_dir = debugfs_create_dir(devname, nfcsim_debugfs_root);
+
+	debugfs_create_u8("dropframe", 0664, dev_dir, &dev->dropframe);
+}
+
+static struct nfcsim *nfcsim_device_new(struct nfcsim_link *link_in,
+					struct nfcsim_link *link_out)
+{
+	struct nfcsim *dev;
+	int rc;
+
+	dev = kzalloc(sizeof(struct nfcsim), GFP_KERNEL);
+	if (!dev)
+		return ERR_PTR(-ENOMEM);
+
+	INIT_DELAYED_WORK(&dev->send_work, nfcsim_send_wq);
+	INIT_WORK(&dev->recv_work, nfcsim_recv_wq);
+
+	dev->nfc_digital_dev =
+			nfc_digital_allocate_device(&nfcsim_digital_ops,
+						    NFC_PROTO_NFC_DEP_MASK,
+						    NFCSIM_CAPABILITIES,
+						    0, 0);
+	if (!dev->nfc_digital_dev) {
+		kfree(dev);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	nfc_digital_set_drvdata(dev->nfc_digital_dev, dev);
+
+	dev->link_in = link_in;
+	dev->link_out = link_out;
+
+	rc = nfc_digital_register_device(dev->nfc_digital_dev);
+	if (rc) {
+		pr_err("Could not register digital device (%d)\n", rc);
+		nfc_digital_free_device(dev->nfc_digital_dev);
+		kfree(dev);
+
+		return ERR_PTR(rc);
+	}
+
+	nfcsim_debugfs_init_dev(dev);
+
+	return dev;
+}
+
+static void nfcsim_device_free(struct nfcsim *dev)
+{
+	nfc_digital_unregister_device(dev->nfc_digital_dev);
+
+	dev->up = false;
+
+	nfcsim_link_shutdown(dev->link_in);
+
+	cancel_delayed_work_sync(&dev->send_work);
+	cancel_work_sync(&dev->recv_work);
+
+	nfc_digital_free_device(dev->nfc_digital_dev);
+
+	kfree(dev);
+}
+
+static struct nfcsim *dev0;
+static struct nfcsim *dev1;
+
+static int __init nfcsim_init(void)
+{
+	struct nfcsim_link *link0, *link1;
+	int rc;
+
+	link0 = nfcsim_link_new();
+	link1 = nfcsim_link_new();
+	if (!link0 || !link1) {
+		rc = -ENOMEM;
+		goto exit_err;
+	}
+
+	nfcsim_debugfs_init();
+
+	dev0 = nfcsim_device_new(link0, link1);
+	if (IS_ERR(dev0)) {
+		rc = PTR_ERR(dev0);
+		goto exit_err;
+	}
+
+	dev1 = nfcsim_device_new(link1, link0);
+	if (IS_ERR(dev1)) {
+		nfcsim_device_free(dev0);
+
+		rc = PTR_ERR(dev1);
+		goto exit_err;
+	}
+
+	pr_info("nfcsim " NFCSIM_VERSION " initialized\n");
+
+	return 0;
+
+exit_err:
+	pr_err("Failed to initialize nfcsim driver (%d)\n", rc);
+
+	if (link0)
+		nfcsim_link_free(link0);
+	if (link1)
+		nfcsim_link_free(link1);
+
+	return rc;
+}
+
+static void __exit nfcsim_exit(void)
+{
+	struct nfcsim_link *link0, *link1;
+
+	link0 = dev0->link_in;
+	link1 = dev0->link_out;
+
+	nfcsim_device_free(dev0);
+	nfcsim_device_free(dev1);
+
+	nfcsim_link_free(link0);
+	nfcsim_link_free(link1);
+
+	nfcsim_debugfs_remove();
+}
+
+module_init(nfcsim_init);
+module_exit(nfcsim_exit);
+
+MODULE_DESCRIPTION("NFCSim driver ver " NFCSIM_VERSION);
+MODULE_VERSION(NFCSIM_VERSION);
+MODULE_LICENSE("GPL");