Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1213 insertions, 0 deletions

diff --git a/drivers/net/wwan/wwan_core.c b/drivers/net/wwan/wwan_core.c
new file mode 100644
index 000000000..62e9f7d6c
--- /dev/null
+++ b/drivers/net/wwan/wwan_core.c
@@ -0,0 +1,1213 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2021, Linaro Ltd <loic.poulain@linaro.org> */
+
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/debugfs.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/idr.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/poll.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+#include <linux/termios.h>
+#include <linux/wwan.h>
+#include <net/rtnetlink.h>
+#include <uapi/linux/wwan.h>
+
+/* Maximum number of minors in use */
+#define WWAN_MAX_MINORS		(1 << MINORBITS)
+
+static DEFINE_MUTEX(wwan_register_lock); /* WWAN device create|remove lock */
+static DEFINE_IDA(minors); /* minors for WWAN port chardevs */
+static DEFINE_IDA(wwan_dev_ids); /* for unique WWAN device IDs */
+static struct class *wwan_class;
+static int wwan_major;
+static struct dentry *wwan_debugfs_dir;
+
+#define to_wwan_dev(d) container_of(d, struct wwan_device, dev)
+#define to_wwan_port(d) container_of(d, struct wwan_port, dev)
+
+/* WWAN port flags */
+#define WWAN_PORT_TX_OFF	0
+
+/**
+ * struct wwan_device - The structure that defines a WWAN device
+ *
+ * @id: WWAN device unique ID.
+ * @dev: Underlying device.
+ * @port_id: Current available port ID to pick.
+ * @ops: wwan device ops
+ * @ops_ctxt: context to pass to ops
+ * @debugfs_dir:  WWAN device debugfs dir
+ */
+struct wwan_device {
+	unsigned int id;
+	struct device dev;
+	atomic_t port_id;
+	const struct wwan_ops *ops;
+	void *ops_ctxt;
+#ifdef CONFIG_WWAN_DEBUGFS
+	struct dentry *debugfs_dir;
+#endif
+};
+
+/**
+ * struct wwan_port - The structure that defines a WWAN port
+ * @type: Port type
+ * @start_count: Port start counter
+ * @flags: Store port state and capabilities
+ * @ops: Pointer to WWAN port operations
+ * @ops_lock: Protect port ops
+ * @dev: Underlying device
+ * @rxq: Buffer inbound queue
+ * @waitqueue: The waitqueue for port fops (read/write/poll)
+ * @data_lock: Port specific data access serialization
+ * @at_data: AT port specific data
+ */
+struct wwan_port {
+	enum wwan_port_type type;
+	unsigned int start_count;
+	unsigned long flags;
+	const struct wwan_port_ops *ops;
+	struct mutex ops_lock; /* Serialize ops + protect against removal */
+	struct device dev;
+	struct sk_buff_head rxq;
+	wait_queue_head_t waitqueue;
+	struct mutex data_lock;	/* Port specific data access serialization */
+	union {
+		struct {
+			struct ktermios termios;
+			int mdmbits;
+		} at_data;
+	};
+};
+
+static ssize_t index_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct wwan_device *wwan = to_wwan_dev(dev);
+
+	return sprintf(buf, "%d\n", wwan->id);
+}
+static DEVICE_ATTR_RO(index);
+
+static struct attribute *wwan_dev_attrs[] = {
+	&dev_attr_index.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(wwan_dev);
+
+static void wwan_dev_destroy(struct device *dev)
+{
+	struct wwan_device *wwandev = to_wwan_dev(dev);
+
+	ida_free(&wwan_dev_ids, wwandev->id);
+	kfree(wwandev);
+}
+
+static const struct device_type wwan_dev_type = {
+	.name    = "wwan_dev",
+	.release = wwan_dev_destroy,
+	.groups = wwan_dev_groups,
+};
+
+static int wwan_dev_parent_match(struct device *dev, const void *parent)
+{
+	return (dev->type == &wwan_dev_type &&
+		(dev->parent == parent || dev == parent));
+}
+
+static struct wwan_device *wwan_dev_get_by_parent(struct device *parent)
+{
+	struct device *dev;
+
+	dev = class_find_device(wwan_class, NULL, parent, wwan_dev_parent_match);
+	if (!dev)
+		return ERR_PTR(-ENODEV);
+
+	return to_wwan_dev(dev);
+}
+
+static int wwan_dev_name_match(struct device *dev, const void *name)
+{
+	return dev->type == &wwan_dev_type &&
+	       strcmp(dev_name(dev), name) == 0;
+}
+
+static struct wwan_device *wwan_dev_get_by_name(const char *name)
+{
+	struct device *dev;
+
+	dev = class_find_device(wwan_class, NULL, name, wwan_dev_name_match);
+	if (!dev)
+		return ERR_PTR(-ENODEV);
+
+	return to_wwan_dev(dev);
+}
+
+#ifdef CONFIG_WWAN_DEBUGFS
+struct dentry *wwan_get_debugfs_dir(struct device *parent)
+{
+	struct wwan_device *wwandev;
+
+	wwandev = wwan_dev_get_by_parent(parent);
+	if (IS_ERR(wwandev))
+		return ERR_CAST(wwandev);
+
+	return wwandev->debugfs_dir;
+}
+EXPORT_SYMBOL_GPL(wwan_get_debugfs_dir);
+
+static int wwan_dev_debugfs_match(struct device *dev, const void *dir)
+{
+	struct wwan_device *wwandev;
+
+	if (dev->type != &wwan_dev_type)
+		return 0;
+
+	wwandev = to_wwan_dev(dev);
+
+	return wwandev->debugfs_dir == dir;
+}
+
+static struct wwan_device *wwan_dev_get_by_debugfs(struct dentry *dir)
+{
+	struct device *dev;
+
+	dev = class_find_device(wwan_class, NULL, dir, wwan_dev_debugfs_match);
+	if (!dev)
+		return ERR_PTR(-ENODEV);
+
+	return to_wwan_dev(dev);
+}
+
+void wwan_put_debugfs_dir(struct dentry *dir)
+{
+	struct wwan_device *wwandev = wwan_dev_get_by_debugfs(dir);
+
+	if (WARN_ON(IS_ERR(wwandev)))
+		return;
+
+	/* wwan_dev_get_by_debugfs() also got a reference */
+	put_device(&wwandev->dev);
+	put_device(&wwandev->dev);
+}
+EXPORT_SYMBOL_GPL(wwan_put_debugfs_dir);
+#endif
+
+/* This function allocates and registers a new WWAN device OR if a WWAN device
+ * already exist for the given parent, it gets a reference and return it.
+ * This function is not exported (for now), it is called indirectly via
+ * wwan_create_port().
+ */
+static struct wwan_device *wwan_create_dev(struct device *parent)
+{
+	struct wwan_device *wwandev;
+	int err, id;
+
+	/* The 'find-alloc-register' operation must be protected against
+	 * concurrent execution, a WWAN device is possibly shared between
+	 * multiple callers or concurrently unregistered from wwan_remove_dev().
+	 */
+	mutex_lock(&wwan_register_lock);
+
+	/* If wwandev already exists, return it */
+	wwandev = wwan_dev_get_by_parent(parent);
+	if (!IS_ERR(wwandev))
+		goto done_unlock;
+
+	id = ida_alloc(&wwan_dev_ids, GFP_KERNEL);
+	if (id < 0) {
+		wwandev = ERR_PTR(id);
+		goto done_unlock;
+	}
+
+	wwandev = kzalloc(sizeof(*wwandev), GFP_KERNEL);
+	if (!wwandev) {
+		wwandev = ERR_PTR(-ENOMEM);
+		ida_free(&wwan_dev_ids, id);
+		goto done_unlock;
+	}
+
+	wwandev->dev.parent = parent;
+	wwandev->dev.class = wwan_class;
+	wwandev->dev.type = &wwan_dev_type;
+	wwandev->id = id;
+	dev_set_name(&wwandev->dev, "wwan%d", wwandev->id);
+
+	err = device_register(&wwandev->dev);
+	if (err) {
+		put_device(&wwandev->dev);
+		wwandev = ERR_PTR(err);
+		goto done_unlock;
+	}
+
+#ifdef CONFIG_WWAN_DEBUGFS
+	wwandev->debugfs_dir =
+			debugfs_create_dir(kobject_name(&wwandev->dev.kobj),
+					   wwan_debugfs_dir);
+#endif
+
+done_unlock:
+	mutex_unlock(&wwan_register_lock);
+
+	return wwandev;
+}
+
+static int is_wwan_child(struct device *dev, void *data)
+{
+	return dev->class == wwan_class;
+}
+
+static void wwan_remove_dev(struct wwan_device *wwandev)
+{
+	int ret;
+
+	/* Prevent concurrent picking from wwan_create_dev */
+	mutex_lock(&wwan_register_lock);
+
+	/* WWAN device is created and registered (get+add) along with its first
+	 * child port, and subsequent port registrations only grab a reference
+	 * (get). The WWAN device must then be unregistered (del+put) along with
+	 * its last port, and reference simply dropped (put) otherwise. In the
+	 * same fashion, we must not unregister it when the ops are still there.
+	 */
+	if (wwandev->ops)
+		ret = 1;
+	else
+		ret = device_for_each_child(&wwandev->dev, NULL, is_wwan_child);
+
+	if (!ret) {
+#ifdef CONFIG_WWAN_DEBUGFS
+		debugfs_remove_recursive(wwandev->debugfs_dir);
+#endif
+		device_unregister(&wwandev->dev);
+	} else {
+		put_device(&wwandev->dev);
+	}
+
+	mutex_unlock(&wwan_register_lock);
+}
+
+/* ------- WWAN port management ------- */
+
+static const struct {
+	const char * const name;	/* Port type name */
+	const char * const devsuf;	/* Port devce name suffix */
+} wwan_port_types[WWAN_PORT_MAX + 1] = {
+	[WWAN_PORT_AT] = {
+		.name = "AT",
+		.devsuf = "at",
+	},
+	[WWAN_PORT_MBIM] = {
+		.name = "MBIM",
+		.devsuf = "mbim",
+	},
+	[WWAN_PORT_QMI] = {
+		.name = "QMI",
+		.devsuf = "qmi",
+	},
+	[WWAN_PORT_QCDM] = {
+		.name = "QCDM",
+		.devsuf = "qcdm",
+	},
+	[WWAN_PORT_FIREHOSE] = {
+		.name = "FIREHOSE",
+		.devsuf = "firehose",
+	},
+};
+
+static ssize_t type_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct wwan_port *port = to_wwan_port(dev);
+
+	return sprintf(buf, "%s\n", wwan_port_types[port->type].name);
+}
+static DEVICE_ATTR_RO(type);
+
+static struct attribute *wwan_port_attrs[] = {
+	&dev_attr_type.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(wwan_port);
+
+static void wwan_port_destroy(struct device *dev)
+{
+	struct wwan_port *port = to_wwan_port(dev);
+
+	ida_free(&minors, MINOR(port->dev.devt));
+	mutex_destroy(&port->data_lock);
+	mutex_destroy(&port->ops_lock);
+	kfree(port);
+}
+
+static const struct device_type wwan_port_dev_type = {
+	.name = "wwan_port",
+	.release = wwan_port_destroy,
+	.groups = wwan_port_groups,
+};
+
+static int wwan_port_minor_match(struct device *dev, const void *minor)
+{
+	return (dev->type == &wwan_port_dev_type &&
+		MINOR(dev->devt) == *(unsigned int *)minor);
+}
+
+static struct wwan_port *wwan_port_get_by_minor(unsigned int minor)
+{
+	struct device *dev;
+
+	dev = class_find_device(wwan_class, NULL, &minor, wwan_port_minor_match);
+	if (!dev)
+		return ERR_PTR(-ENODEV);
+
+	return to_wwan_port(dev);
+}
+
+/* Allocate and set unique name based on passed format
+ *
+ * Name allocation approach is highly inspired by the __dev_alloc_name()
+ * function.
+ *
+ * To avoid names collision, the caller must prevent the new port device
+ * registration as well as concurrent invocation of this function.
+ */
+static int __wwan_port_dev_assign_name(struct wwan_port *port, const char *fmt)
+{
+	struct wwan_device *wwandev = to_wwan_dev(port->dev.parent);
+	const unsigned int max_ports = PAGE_SIZE * 8;
+	struct class_dev_iter iter;
+	unsigned long *idmap;
+	struct device *dev;
+	char buf[0x20];
+	int id;
+
+	idmap = (unsigned long *)get_zeroed_page(GFP_KERNEL);
+	if (!idmap)
+		return -ENOMEM;
+
+	/* Collect ids of same name format ports */
+	class_dev_iter_init(&iter, wwan_class, NULL, &wwan_port_dev_type);
+	while ((dev = class_dev_iter_next(&iter))) {
+		if (dev->parent != &wwandev->dev)
+			continue;
+		if (sscanf(dev_name(dev), fmt, &id) != 1)
+			continue;
+		if (id < 0 || id >= max_ports)
+			continue;
+		set_bit(id, idmap);
+	}
+	class_dev_iter_exit(&iter);
+
+	/* Allocate unique id */
+	id = find_first_zero_bit(idmap, max_ports);
+	free_page((unsigned long)idmap);
+
+	snprintf(buf, sizeof(buf), fmt, id);	/* Name generation */
+
+	dev = device_find_child_by_name(&wwandev->dev, buf);
+	if (dev) {
+		put_device(dev);
+		return -ENFILE;
+	}
+
+	return dev_set_name(&port->dev, buf);
+}
+
+struct wwan_port *wwan_create_port(struct device *parent,
+				   enum wwan_port_type type,
+				   const struct wwan_port_ops *ops,
+				   void *drvdata)
+{
+	struct wwan_device *wwandev;
+	struct wwan_port *port;
+	char namefmt[0x20];
+	int minor, err;
+
+	if (type > WWAN_PORT_MAX || !ops)
+		return ERR_PTR(-EINVAL);
+
+	/* A port is always a child of a WWAN device, retrieve (allocate or
+	 * pick) the WWAN device based on the provided parent device.
+	 */
+	wwandev = wwan_create_dev(parent);
+	if (IS_ERR(wwandev))
+		return ERR_CAST(wwandev);
+
+	/* A port is exposed as character device, get a minor */
+	minor = ida_alloc_range(&minors, 0, WWAN_MAX_MINORS - 1, GFP_KERNEL);
+	if (minor < 0) {
+		err = minor;
+		goto error_wwandev_remove;
+	}
+
+	port = kzalloc(sizeof(*port), GFP_KERNEL);
+	if (!port) {
+		err = -ENOMEM;
+		ida_free(&minors, minor);
+		goto error_wwandev_remove;
+	}
+
+	port->type = type;
+	port->ops = ops;
+	mutex_init(&port->ops_lock);
+	skb_queue_head_init(&port->rxq);
+	init_waitqueue_head(&port->waitqueue);
+	mutex_init(&port->data_lock);
+
+	port->dev.parent = &wwandev->dev;
+	port->dev.class = wwan_class;
+	port->dev.type = &wwan_port_dev_type;
+	port->dev.devt = MKDEV(wwan_major, minor);
+	dev_set_drvdata(&port->dev, drvdata);
+
+	/* allocate unique name based on wwan device id, port type and number */
+	snprintf(namefmt, sizeof(namefmt), "wwan%u%s%%d", wwandev->id,
+		 wwan_port_types[port->type].devsuf);
+
+	/* Serialize ports registration */
+	mutex_lock(&wwan_register_lock);
+
+	__wwan_port_dev_assign_name(port, namefmt);
+	err = device_register(&port->dev);
+
+	mutex_unlock(&wwan_register_lock);
+
+	if (err)
+		goto error_put_device;
+
+	return port;
+
+error_put_device:
+	put_device(&port->dev);
+error_wwandev_remove:
+	wwan_remove_dev(wwandev);
+
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL_GPL(wwan_create_port);
+
+void wwan_remove_port(struct wwan_port *port)
+{
+	struct wwan_device *wwandev = to_wwan_dev(port->dev.parent);
+
+	mutex_lock(&port->ops_lock);
+	if (port->start_count)
+		port->ops->stop(port);
+	port->ops = NULL; /* Prevent any new port operations (e.g. from fops) */
+	mutex_unlock(&port->ops_lock);
+
+	wake_up_interruptible(&port->waitqueue);
+
+	skb_queue_purge(&port->rxq);
+	dev_set_drvdata(&port->dev, NULL);
+	device_unregister(&port->dev);
+
+	/* Release related wwan device */
+	wwan_remove_dev(wwandev);
+}
+EXPORT_SYMBOL_GPL(wwan_remove_port);
+
+void wwan_port_rx(struct wwan_port *port, struct sk_buff *skb)
+{
+	skb_queue_tail(&port->rxq, skb);
+	wake_up_interruptible(&port->waitqueue);
+}
+EXPORT_SYMBOL_GPL(wwan_port_rx);
+
+void wwan_port_txon(struct wwan_port *port)
+{
+	clear_bit(WWAN_PORT_TX_OFF, &port->flags);
+	wake_up_interruptible(&port->waitqueue);
+}
+EXPORT_SYMBOL_GPL(wwan_port_txon);
+
+void wwan_port_txoff(struct wwan_port *port)
+{
+	set_bit(WWAN_PORT_TX_OFF, &port->flags);
+}
+EXPORT_SYMBOL_GPL(wwan_port_txoff);
+
+void *wwan_port_get_drvdata(struct wwan_port *port)
+{
+	return dev_get_drvdata(&port->dev);
+}
+EXPORT_SYMBOL_GPL(wwan_port_get_drvdata);
+
+static int wwan_port_op_start(struct wwan_port *port)
+{
+	int ret = 0;
+
+	mutex_lock(&port->ops_lock);
+	if (!port->ops) { /* Port got unplugged */
+		ret = -ENODEV;
+		goto out_unlock;
+	}
+
+	/* If port is already started, don't start again */
+	if (!port->start_count)
+		ret = port->ops->start(port);
+
+	if (!ret)
+		port->start_count++;
+
+out_unlock:
+	mutex_unlock(&port->ops_lock);
+
+	return ret;
+}
+
+static void wwan_port_op_stop(struct wwan_port *port)
+{
+	mutex_lock(&port->ops_lock);
+	port->start_count--;
+	if (!port->start_count) {
+		if (port->ops)
+			port->ops->stop(port);
+		skb_queue_purge(&port->rxq);
+	}
+	mutex_unlock(&port->ops_lock);
+}
+
+static int wwan_port_op_tx(struct wwan_port *port, struct sk_buff *skb,
+			   bool nonblock)
+{
+	int ret;
+
+	mutex_lock(&port->ops_lock);
+	if (!port->ops) { /* Port got unplugged */
+		ret = -ENODEV;
+		goto out_unlock;
+	}
+
+	if (nonblock || !port->ops->tx_blocking)
+		ret = port->ops->tx(port, skb);
+	else
+		ret = port->ops->tx_blocking(port, skb);
+
+out_unlock:
+	mutex_unlock(&port->ops_lock);
+
+	return ret;
+}
+
+static bool is_read_blocked(struct wwan_port *port)
+{
+	return skb_queue_empty(&port->rxq) && port->ops;
+}
+
+static bool is_write_blocked(struct wwan_port *port)
+{
+	return test_bit(WWAN_PORT_TX_OFF, &port->flags) && port->ops;
+}
+
+static int wwan_wait_rx(struct wwan_port *port, bool nonblock)
+{
+	if (!is_read_blocked(port))
+		return 0;
+
+	if (nonblock)
+		return -EAGAIN;
+
+	if (wait_event_interruptible(port->waitqueue, !is_read_blocked(port)))
+		return -ERESTARTSYS;
+
+	return 0;
+}
+
+static int wwan_wait_tx(struct wwan_port *port, bool nonblock)
+{
+	if (!is_write_blocked(port))
+		return 0;
+
+	if (nonblock)
+		return -EAGAIN;
+
+	if (wait_event_interruptible(port->waitqueue, !is_write_blocked(port)))
+		return -ERESTARTSYS;
+
+	return 0;
+}
+
+static int wwan_port_fops_open(struct inode *inode, struct file *file)
+{
+	struct wwan_port *port;
+	int err = 0;
+
+	port = wwan_port_get_by_minor(iminor(inode));
+	if (IS_ERR(port))
+		return PTR_ERR(port);
+
+	file->private_data = port;
+	stream_open(inode, file);
+
+	err = wwan_port_op_start(port);
+	if (err)
+		put_device(&port->dev);
+
+	return err;
+}
+
+static int wwan_port_fops_release(struct inode *inode, struct file *filp)
+{
+	struct wwan_port *port = filp->private_data;
+
+	wwan_port_op_stop(port);
+	put_device(&port->dev);
+
+	return 0;
+}
+
+static ssize_t wwan_port_fops_read(struct file *filp, char __user *buf,
+				   size_t count, loff_t *ppos)
+{
+	struct wwan_port *port = filp->private_data;
+	struct sk_buff *skb;
+	size_t copied;
+	int ret;
+
+	ret = wwan_wait_rx(port, !!(filp->f_flags & O_NONBLOCK));
+	if (ret)
+		return ret;
+
+	skb = skb_dequeue(&port->rxq);
+	if (!skb)
+		return -EIO;
+
+	copied = min_t(size_t, count, skb->len);
+	if (copy_to_user(buf, skb->data, copied)) {
+		kfree_skb(skb);
+		return -EFAULT;
+	}
+	skb_pull(skb, copied);
+
+	/* skb is not fully consumed, keep it in the queue */
+	if (skb->len)
+		skb_queue_head(&port->rxq, skb);
+	else
+		consume_skb(skb);
+
+	return copied;
+}
+
+static ssize_t wwan_port_fops_write(struct file *filp, const char __user *buf,
+				    size_t count, loff_t *offp)
+{
+	struct wwan_port *port = filp->private_data;
+	struct sk_buff *skb;
+	int ret;
+
+	ret = wwan_wait_tx(port, !!(filp->f_flags & O_NONBLOCK));
+	if (ret)
+		return ret;
+
+	skb = alloc_skb(count, GFP_KERNEL);
+	if (!skb)
+		return -ENOMEM;
+
+	if (copy_from_user(skb_put(skb, count), buf, count)) {
+		kfree_skb(skb);
+		return -EFAULT;
+	}
+
+	ret = wwan_port_op_tx(port, skb, !!(filp->f_flags & O_NONBLOCK));
+	if (ret) {
+		kfree_skb(skb);
+		return ret;
+	}
+
+	return count;
+}
+
+static __poll_t wwan_port_fops_poll(struct file *filp, poll_table *wait)
+{
+	struct wwan_port *port = filp->private_data;
+	__poll_t mask = 0;
+
+	poll_wait(filp, &port->waitqueue, wait);
+
+	mutex_lock(&port->ops_lock);
+	if (port->ops && port->ops->tx_poll)
+		mask |= port->ops->tx_poll(port, filp, wait);
+	else if (!is_write_blocked(port))
+		mask |= EPOLLOUT | EPOLLWRNORM;
+	if (!is_read_blocked(port))
+		mask |= EPOLLIN | EPOLLRDNORM;
+	if (!port->ops)
+		mask |= EPOLLHUP | EPOLLERR;
+	mutex_unlock(&port->ops_lock);
+
+	return mask;
+}
+
+/* Implements minimalistic stub terminal IOCTLs support */
+static long wwan_port_fops_at_ioctl(struct wwan_port *port, unsigned int cmd,
+				    unsigned long arg)
+{
+	int ret = 0;
+
+	mutex_lock(&port->data_lock);
+
+	switch (cmd) {
+	case TCFLSH:
+		break;
+
+	case TCGETS:
+		if (copy_to_user((void __user *)arg, &port->at_data.termios,
+				 sizeof(struct termios)))
+			ret = -EFAULT;
+		break;
+
+	case TCSETS:
+	case TCSETSW:
+	case TCSETSF:
+		if (copy_from_user(&port->at_data.termios, (void __user *)arg,
+				   sizeof(struct termios)))
+			ret = -EFAULT;
+		break;
+
+#ifdef TCGETS2
+	case TCGETS2:
+		if (copy_to_user((void __user *)arg, &port->at_data.termios,
+				 sizeof(struct termios2)))
+			ret = -EFAULT;
+		break;
+
+	case TCSETS2:
+	case TCSETSW2:
+	case TCSETSF2:
+		if (copy_from_user(&port->at_data.termios, (void __user *)arg,
+				   sizeof(struct termios2)))
+			ret = -EFAULT;
+		break;
+#endif
+
+	case TIOCMGET:
+		ret = put_user(port->at_data.mdmbits, (int __user *)arg);
+		break;
+
+	case TIOCMSET:
+	case TIOCMBIC:
+	case TIOCMBIS: {
+		int mdmbits;
+
+		if (copy_from_user(&mdmbits, (int __user *)arg, sizeof(int))) {
+			ret = -EFAULT;
+			break;
+		}
+		if (cmd == TIOCMBIC)
+			port->at_data.mdmbits &= ~mdmbits;
+		else if (cmd == TIOCMBIS)
+			port->at_data.mdmbits |= mdmbits;
+		else
+			port->at_data.mdmbits = mdmbits;
+		break;
+	}
+
+	default:
+		ret = -ENOIOCTLCMD;
+	}
+
+	mutex_unlock(&port->data_lock);
+
+	return ret;
+}
+
+static long wwan_port_fops_ioctl(struct file *filp, unsigned int cmd,
+				 unsigned long arg)
+{
+	struct wwan_port *port = filp->private_data;
+	int res;
+
+	if (port->type == WWAN_PORT_AT) {	/* AT port specific IOCTLs */
+		res = wwan_port_fops_at_ioctl(port, cmd, arg);
+		if (res != -ENOIOCTLCMD)
+			return res;
+	}
+
+	switch (cmd) {
+	case TIOCINQ: {	/* aka SIOCINQ aka FIONREAD */
+		unsigned long flags;
+		struct sk_buff *skb;
+		int amount = 0;
+
+		spin_lock_irqsave(&port->rxq.lock, flags);
+		skb_queue_walk(&port->rxq, skb)
+			amount += skb->len;
+		spin_unlock_irqrestore(&port->rxq.lock, flags);
+
+		return put_user(amount, (int __user *)arg);
+	}
+
+	default:
+		return -ENOIOCTLCMD;
+	}
+}
+
+static const struct file_operations wwan_port_fops = {
+	.owner = THIS_MODULE,
+	.open = wwan_port_fops_open,
+	.release = wwan_port_fops_release,
+	.read = wwan_port_fops_read,
+	.write = wwan_port_fops_write,
+	.poll = wwan_port_fops_poll,
+	.unlocked_ioctl = wwan_port_fops_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl = compat_ptr_ioctl,
+#endif
+	.llseek = noop_llseek,
+};
+
+static int wwan_rtnl_validate(struct nlattr *tb[], struct nlattr *data[],
+			      struct netlink_ext_ack *extack)
+{
+	if (!data)
+		return -EINVAL;
+
+	if (!tb[IFLA_PARENT_DEV_NAME])
+		return -EINVAL;
+
+	if (!data[IFLA_WWAN_LINK_ID])
+		return -EINVAL;
+
+	return 0;
+}
+
+static struct device_type wwan_type = { .name = "wwan" };
+
+static struct net_device *wwan_rtnl_alloc(struct nlattr *tb[],
+					  const char *ifname,
+					  unsigned char name_assign_type,
+					  unsigned int num_tx_queues,
+					  unsigned int num_rx_queues)
+{
+	const char *devname = nla_data(tb[IFLA_PARENT_DEV_NAME]);
+	struct wwan_device *wwandev = wwan_dev_get_by_name(devname);
+	struct net_device *dev;
+	unsigned int priv_size;
+
+	if (IS_ERR(wwandev))
+		return ERR_CAST(wwandev);
+
+	/* only supported if ops were registered (not just ports) */
+	if (!wwandev->ops) {
+		dev = ERR_PTR(-EOPNOTSUPP);
+		goto out;
+	}
+
+	priv_size = sizeof(struct wwan_netdev_priv) + wwandev->ops->priv_size;
+	dev = alloc_netdev_mqs(priv_size, ifname, name_assign_type,
+			       wwandev->ops->setup, num_tx_queues, num_rx_queues);
+
+	if (dev) {
+		SET_NETDEV_DEV(dev, &wwandev->dev);
+		SET_NETDEV_DEVTYPE(dev, &wwan_type);
+	}
+
+out:
+	/* release the reference */
+	put_device(&wwandev->dev);
+	return dev;
+}
+
+static int wwan_rtnl_newlink(struct net *src_net, struct net_device *dev,
+			     struct nlattr *tb[], struct nlattr *data[],
+			     struct netlink_ext_ack *extack)
+{
+	struct wwan_device *wwandev = wwan_dev_get_by_parent(dev->dev.parent);
+	u32 link_id = nla_get_u32(data[IFLA_WWAN_LINK_ID]);
+	struct wwan_netdev_priv *priv = netdev_priv(dev);
+	int ret;
+
+	if (IS_ERR(wwandev))
+		return PTR_ERR(wwandev);
+
+	/* shouldn't have a netdev (left) with us as parent so WARN */
+	if (WARN_ON(!wwandev->ops)) {
+		ret = -EOPNOTSUPP;
+		goto out;
+	}
+
+	priv->link_id = link_id;
+	if (wwandev->ops->newlink)
+		ret = wwandev->ops->newlink(wwandev->ops_ctxt, dev,
+					    link_id, extack);
+	else
+		ret = register_netdevice(dev);
+
+out:
+	/* release the reference */
+	put_device(&wwandev->dev);
+	return ret;
+}
+
+static void wwan_rtnl_dellink(struct net_device *dev, struct list_head *head)
+{
+	struct wwan_device *wwandev = wwan_dev_get_by_parent(dev->dev.parent);
+
+	if (IS_ERR(wwandev))
+		return;
+
+	/* shouldn't have a netdev (left) with us as parent so WARN */
+	if (WARN_ON(!wwandev->ops))
+		goto out;
+
+	if (wwandev->ops->dellink)
+		wwandev->ops->dellink(wwandev->ops_ctxt, dev, head);
+	else
+		unregister_netdevice_queue(dev, head);
+
+out:
+	/* release the reference */
+	put_device(&wwandev->dev);
+}
+
+static size_t wwan_rtnl_get_size(const struct net_device *dev)
+{
+	return
+		nla_total_size(4) +	/* IFLA_WWAN_LINK_ID */
+		0;
+}
+
+static int wwan_rtnl_fill_info(struct sk_buff *skb,
+			       const struct net_device *dev)
+{
+	struct wwan_netdev_priv *priv = netdev_priv(dev);
+
+	if (nla_put_u32(skb, IFLA_WWAN_LINK_ID, priv->link_id))
+		goto nla_put_failure;
+
+	return 0;
+
+nla_put_failure:
+	return -EMSGSIZE;
+}
+
+static const struct nla_policy wwan_rtnl_policy[IFLA_WWAN_MAX + 1] = {
+	[IFLA_WWAN_LINK_ID] = { .type = NLA_U32 },
+};
+
+static struct rtnl_link_ops wwan_rtnl_link_ops __read_mostly = {
+	.kind = "wwan",
+	.maxtype = __IFLA_WWAN_MAX,
+	.alloc = wwan_rtnl_alloc,
+	.validate = wwan_rtnl_validate,
+	.newlink = wwan_rtnl_newlink,
+	.dellink = wwan_rtnl_dellink,
+	.get_size = wwan_rtnl_get_size,
+	.fill_info = wwan_rtnl_fill_info,
+	.policy = wwan_rtnl_policy,
+};
+
+static void wwan_create_default_link(struct wwan_device *wwandev,
+				     u32 def_link_id)
+{
+	struct nlattr *tb[IFLA_MAX + 1], *linkinfo[IFLA_INFO_MAX + 1];
+	struct nlattr *data[IFLA_WWAN_MAX + 1];
+	struct net_device *dev;
+	struct nlmsghdr *nlh;
+	struct sk_buff *msg;
+
+	/* Forge attributes required to create a WWAN netdev. We first
+	 * build a netlink message and then parse it. This looks
+	 * odd, but such approach is less error prone.
+	 */
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (WARN_ON(!msg))
+		return;
+	nlh = nlmsg_put(msg, 0, 0, RTM_NEWLINK, 0, 0);
+	if (WARN_ON(!nlh))
+		goto free_attrs;
+
+	if (nla_put_string(msg, IFLA_PARENT_DEV_NAME, dev_name(&wwandev->dev)))
+		goto free_attrs;
+	tb[IFLA_LINKINFO] = nla_nest_start(msg, IFLA_LINKINFO);
+	if (!tb[IFLA_LINKINFO])
+		goto free_attrs;
+	linkinfo[IFLA_INFO_DATA] = nla_nest_start(msg, IFLA_INFO_DATA);
+	if (!linkinfo[IFLA_INFO_DATA])
+		goto free_attrs;
+	if (nla_put_u32(msg, IFLA_WWAN_LINK_ID, def_link_id))
+		goto free_attrs;
+	nla_nest_end(msg, linkinfo[IFLA_INFO_DATA]);
+	nla_nest_end(msg, tb[IFLA_LINKINFO]);
+
+	nlmsg_end(msg, nlh);
+
+	/* The next three parsing calls can not fail */
+	nlmsg_parse_deprecated(nlh, 0, tb, IFLA_MAX, NULL, NULL);
+	nla_parse_nested_deprecated(linkinfo, IFLA_INFO_MAX, tb[IFLA_LINKINFO],
+				    NULL, NULL);
+	nla_parse_nested_deprecated(data, IFLA_WWAN_MAX,
+				    linkinfo[IFLA_INFO_DATA], NULL, NULL);
+
+	rtnl_lock();
+
+	dev = rtnl_create_link(&init_net, "wwan%d", NET_NAME_ENUM,
+			       &wwan_rtnl_link_ops, tb, NULL);
+	if (WARN_ON(IS_ERR(dev)))
+		goto unlock;
+
+	if (WARN_ON(wwan_rtnl_newlink(&init_net, dev, tb, data, NULL))) {
+		free_netdev(dev);
+		goto unlock;
+	}
+
+	rtnl_configure_link(dev, NULL); /* Link initialized, notify new link */
+
+unlock:
+	rtnl_unlock();
+
+free_attrs:
+	nlmsg_free(msg);
+}
+
+/**
+ * wwan_register_ops - register WWAN device ops
+ * @parent: Device to use as parent and shared by all WWAN ports and
+ *	created netdevs
+ * @ops: operations to register
+ * @ctxt: context to pass to operations
+ * @def_link_id: id of the default link that will be automatically created by
+ *	the WWAN core for the WWAN device. The default link will not be created
+ *	if the passed value is WWAN_NO_DEFAULT_LINK.
+ *
+ * Returns: 0 on success, a negative error code on failure
+ */
+int wwan_register_ops(struct device *parent, const struct wwan_ops *ops,
+		      void *ctxt, u32 def_link_id)
+{
+	struct wwan_device *wwandev;
+
+	if (WARN_ON(!parent || !ops || !ops->setup))
+		return -EINVAL;
+
+	wwandev = wwan_create_dev(parent);
+	if (IS_ERR(wwandev))
+		return PTR_ERR(wwandev);
+
+	if (WARN_ON(wwandev->ops)) {
+		wwan_remove_dev(wwandev);
+		return -EBUSY;
+	}
+
+	wwandev->ops = ops;
+	wwandev->ops_ctxt = ctxt;
+
+	/* NB: we do not abort ops registration in case of default link
+	 * creation failure. Link ops is the management interface, while the
+	 * default link creation is a service option. And we should not prevent
+	 * a user from manually creating a link latter if service option failed
+	 * now.
+	 */
+	if (def_link_id != WWAN_NO_DEFAULT_LINK)
+		wwan_create_default_link(wwandev, def_link_id);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(wwan_register_ops);
+
+/* Enqueue child netdev deletion */
+static int wwan_child_dellink(struct device *dev, void *data)
+{
+	struct list_head *kill_list = data;
+
+	if (dev->type == &wwan_type)
+		wwan_rtnl_dellink(to_net_dev(dev), kill_list);
+
+	return 0;
+}
+
+/**
+ * wwan_unregister_ops - remove WWAN device ops
+ * @parent: Device to use as parent and shared by all WWAN ports and
+ *	created netdevs
+ */
+void wwan_unregister_ops(struct device *parent)
+{
+	struct wwan_device *wwandev = wwan_dev_get_by_parent(parent);
+	LIST_HEAD(kill_list);
+
+	if (WARN_ON(IS_ERR(wwandev)))
+		return;
+	if (WARN_ON(!wwandev->ops)) {
+		put_device(&wwandev->dev);
+		return;
+	}
+
+	/* put the reference obtained by wwan_dev_get_by_parent(),
+	 * we should still have one (that the owner is giving back
+	 * now) due to the ops being assigned.
+	 */
+	put_device(&wwandev->dev);
+
+	rtnl_lock();	/* Prevent concurent netdev(s) creation/destroying */
+
+	/* Remove all child netdev(s), using batch removing */
+	device_for_each_child(&wwandev->dev, &kill_list,
+			      wwan_child_dellink);
+	unregister_netdevice_many(&kill_list);
+
+	wwandev->ops = NULL;	/* Finally remove ops */
+
+	rtnl_unlock();
+
+	wwandev->ops_ctxt = NULL;
+	wwan_remove_dev(wwandev);
+}
+EXPORT_SYMBOL_GPL(wwan_unregister_ops);
+
+static int __init wwan_init(void)
+{
+	int err;
+
+	err = rtnl_link_register(&wwan_rtnl_link_ops);
+	if (err)
+		return err;
+
+	wwan_class = class_create(THIS_MODULE, "wwan");
+	if (IS_ERR(wwan_class)) {
+		err = PTR_ERR(wwan_class);
+		goto unregister;
+	}
+
+	/* chrdev used for wwan ports */
+	wwan_major = __register_chrdev(0, 0, WWAN_MAX_MINORS, "wwan_port",
+				       &wwan_port_fops);
+	if (wwan_major < 0) {
+		err = wwan_major;
+		goto destroy;
+	}
+
+#ifdef CONFIG_WWAN_DEBUGFS
+	wwan_debugfs_dir = debugfs_create_dir("wwan", NULL);
+#endif
+
+	return 0;
+
+destroy:
+	class_destroy(wwan_class);
+unregister:
+	rtnl_link_unregister(&wwan_rtnl_link_ops);
+	return err;
+}
+
+static void __exit wwan_exit(void)
+{
+	debugfs_remove_recursive(wwan_debugfs_dir);
+	__unregister_chrdev(wwan_major, 0, WWAN_MAX_MINORS, "wwan_port");
+	rtnl_link_unregister(&wwan_rtnl_link_ops);
+	class_destroy(wwan_class);
+}
+
+module_init(wwan_init);
+module_exit(wwan_exit);
+
+MODULE_AUTHOR("Loic Poulain <loic.poulain@linaro.org>");
+MODULE_DESCRIPTION("WWAN core");
+MODULE_LICENSE("GPL v2");