diff options
| -rw-r--r-- | drivers/net/Kconfig | 2 | ||||
| -rw-r--r-- | drivers/net/Makefile | 1 | ||||
| -rw-r--r-- | drivers/net/wwan/Kconfig | 23 | ||||
| -rw-r--r-- | drivers/net/wwan/Makefile | 7 | ||||
| -rw-r--r-- | drivers/net/wwan/wwan_core.c | 552 | ||||
| -rw-r--r-- | include/linux/wwan.h | 111 |
6 files changed, 696 insertions, 0 deletions
diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig index 5895905b6aa1..74dc8e249faa 100644 --- a/drivers/net/Kconfig +++ b/drivers/net/Kconfig @@ -502,6 +502,8 @@ source "drivers/net/wan/Kconfig" source "drivers/net/ieee802154/Kconfig" +source "drivers/net/wwan/Kconfig" + config XEN_NETDEV_FRONTEND tristate "Xen network device frontend driver" depends on XEN diff --git a/drivers/net/Makefile b/drivers/net/Makefile index 040e20b81317..7ffd2d03efaf 100644 --- a/drivers/net/Makefile +++ b/drivers/net/Makefile @@ -68,6 +68,7 @@ obj-$(CONFIG_SUNGEM_PHY) += sungem_phy.o obj-$(CONFIG_WAN) += wan/ obj-$(CONFIG_WLAN) += wireless/ obj-$(CONFIG_IEEE802154) += ieee802154/ +obj-$(CONFIG_WWAN) += wwan/ obj-$(CONFIG_VMXNET3) += vmxnet3/ obj-$(CONFIG_XEN_NETDEV_FRONTEND) += xen-netfront.o diff --git a/drivers/net/wwan/Kconfig b/drivers/net/wwan/Kconfig new file mode 100644 index 000000000000..fc3f3a1c80ee --- /dev/null +++ b/drivers/net/wwan/Kconfig @@ -0,0 +1,23 @@ +# SPDX-License-Identifier: GPL-2.0-only +# +# Wireless WAN device configuration +# + +menuconfig WWAN + bool "Wireless WAN" + help + This section contains Wireless WAN configuration for WWAN framework + and drivers. + +if WWAN + +config WWAN_CORE + tristate "WWAN Driver Core" + help + Say Y here if you want to use the WWAN driver core. This driver + provides a common framework for WWAN drivers. + + To compile this driver as a module, choose M here: the module will be + called wwan. + +endif # WWAN diff --git a/drivers/net/wwan/Makefile b/drivers/net/wwan/Makefile new file mode 100644 index 000000000000..934590b9e47d --- /dev/null +++ b/drivers/net/wwan/Makefile @@ -0,0 +1,7 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# Makefile for the Linux WWAN device drivers. +# + +obj-$(CONFIG_WWAN_CORE) += wwan.o +wwan-objs += wwan_core.o diff --git a/drivers/net/wwan/wwan_core.c b/drivers/net/wwan/wwan_core.c new file mode 100644 index 000000000000..b618b7937846 --- /dev/null +++ b/drivers/net/wwan/wwan_core.c @@ -0,0 +1,552 @@ +// 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/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/wwan.h> + +#define WWAN_MAX_MINORS 256 /* 256 minors allowed with register_chrdev() */ + +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; + +#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 BIT(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. + */ +struct wwan_device { + unsigned int id; + struct device dev; + atomic_t port_id; +}; + +/** + * 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) + */ +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; +}; + +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, +}; + +static int wwan_dev_parent_match(struct device *dev, const void *parent) +{ + return (dev->type == &wwan_dev_type && dev->parent == 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); +} + +/* 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) + goto done_unlock; + + wwandev = kzalloc(sizeof(*wwandev), GFP_KERNEL); + if (!wwandev) { + 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 = NULL; + } + +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 latest port, and reference simply dropped (put) otherwise. + */ + ret = device_for_each_child(&wwandev->dev, NULL, is_wwan_child); + if (!ret) + device_unregister(&wwandev->dev); + else + put_device(&wwandev->dev); + + mutex_unlock(&wwan_register_lock); +} + +/* ------- WWAN port management ------- */ + +static void wwan_port_destroy(struct device *dev) +{ + struct wwan_port *port = to_wwan_port(dev); + + ida_free(&minors, MINOR(port->dev.devt)); + skb_queue_purge(&port->rxq); + mutex_destroy(&port->ops_lock); + kfree(port); +} + +static const struct device_type wwan_port_dev_type = { + .name = "wwan_port", + .release = wwan_port_destroy, +}; + +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); +} + +/* Keep aligned with wwan_port_type enum */ +static const char * const wwan_port_type_str[] = { + "AT", + "MBIM", + "QMI", + "QCDM", + "FIREHOSE" +}; + +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; + int minor, err = -ENOMEM; + + 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) + goto error_wwandev_remove; + + port = kzalloc(sizeof(*port), GFP_KERNEL); + if (!port) { + 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); + + 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); + + /* create unique name based on wwan device id, port index and type */ + dev_set_name(&port->dev, "wwan%up%u%s", wwandev->id, + atomic_inc_return(&wwandev->port_id), + wwan_port_type_str[port->type]); + + err = device_register(&port->dev); + 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->ops && !port->start_count) + port->ops->stop(port); + mutex_unlock(&port->ops_lock); +} + +static int wwan_port_op_tx(struct wwan_port *port, struct sk_buff *skb) +{ + int ret; + + mutex_lock(&port->ops_lock); + if (!port->ops) { /* Port got unplugged */ + ret = -ENODEV; + goto out_unlock; + } + + ret = port->ops->tx(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); + 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); + + if (!is_write_blocked(port)) + mask |= EPOLLOUT | EPOLLWRNORM; + if (!is_read_blocked(port)) + mask |= EPOLLIN | EPOLLRDNORM; + + return mask; +} + +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, + .llseek = noop_llseek, +}; + +static int __init wwan_init(void) +{ + wwan_class = class_create(THIS_MODULE, "wwan"); + if (IS_ERR(wwan_class)) + return PTR_ERR(wwan_class); + + /* chrdev used for wwan ports */ + wwan_major = register_chrdev(0, "wwan_port", &wwan_port_fops); + if (wwan_major < 0) { + class_destroy(wwan_class); + return wwan_major; + } + + return 0; +} + +static void __exit wwan_exit(void) +{ + unregister_chrdev(wwan_major, "wwan_port"); + 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"); diff --git a/include/linux/wwan.h b/include/linux/wwan.h new file mode 100644 index 000000000000..aa05a253dcf9 --- /dev/null +++ b/include/linux/wwan.h @@ -0,0 +1,111 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* Copyright (c) 2021, Linaro Ltd <loic.poulain@linaro.org> */ + +#ifndef __WWAN_H +#define __WWAN_H + +#include <linux/device.h> +#include <linux/kernel.h> +#include <linux/skbuff.h> + +/** + * enum wwan_port_type - WWAN port types + * @WWAN_PORT_AT: AT commands + * @WWAN_PORT_MBIM: Mobile Broadband Interface Model control + * @WWAN_PORT_QMI: Qcom modem/MSM interface for modem control + * @WWAN_PORT_QCDM: Qcom Modem diagnostic interface + * @WWAN_PORT_FIREHOSE: XML based command protocol + * @WWAN_PORT_MAX: Number of supported port types + */ +enum wwan_port_type { + WWAN_PORT_AT, + WWAN_PORT_MBIM, + WWAN_PORT_QMI, + WWAN_PORT_QCDM, + WWAN_PORT_FIREHOSE, + WWAN_PORT_MAX, +}; + +struct wwan_port; + +/** struct wwan_port_ops - The WWAN port operations + * @start: The routine for starting the WWAN port device. + * @stop: The routine for stopping the WWAN port device. + * @tx: The routine that sends WWAN port protocol data to the device. + * + * The wwan_port_ops structure contains a list of low-level operations + * that control a WWAN port device. All functions are mandatory. + */ +struct wwan_port_ops { + int (*start)(struct wwan_port *port); + void (*stop)(struct wwan_port *port); + int (*tx)(struct wwan_port *port, struct sk_buff *skb); +}; + +/** + * wwan_create_port - Add a new WWAN port + * @parent: Device to use as parent and shared by all WWAN ports + * @type: WWAN port type + * @ops: WWAN port operations + * @drvdata: Pointer to caller driver data + * + * Allocate and register a new WWAN port. The port will be automatically exposed + * to user as a character device and attached to the right virtual WWAN device, + * based on the parent pointer. The parent pointer is the device shared by all + * components of a same WWAN modem (e.g. USB dev, PCI dev, MHI controller...). + * + * drvdata will be placed in the WWAN port device driver data and can be + * retrieved with wwan_port_get_drvdata(). + * + * This function must be balanced with a call to wwan_remove_port(). + * + * Returns a valid pointer to wwan_port on success or PTR_ERR on failure + */ +struct wwan_port *wwan_create_port(struct device *parent, + enum wwan_port_type type, + const struct wwan_port_ops *ops, + void *drvdata); + +/** + * wwan_remove_port - Remove a WWAN port + * @port: WWAN port to remove + * + * Remove a previously created port. + */ +void wwan_remove_port(struct wwan_port *port); + +/** + * wwan_port_rx - Receive data from the WWAN port + * @port: WWAN port for which data is received + * @skb: Pointer to the rx buffer + * + * A port driver calls this function upon data reception (MBIM, AT...). + */ +void wwan_port_rx(struct wwan_port *port, struct sk_buff *skb); + +/** + * wwan_port_txoff - Stop TX on WWAN port + * @port: WWAN port for which TX must be stopped + * + * Used for TX flow control, a port driver calls this function to indicate TX + * is temporary unavailable (e.g. due to ring buffer fullness). + */ +void wwan_port_txoff(struct wwan_port *port); + + +/** + * wwan_port_txon - Restart TX on WWAN port + * @port: WWAN port for which TX must be restarted + * + * Used for TX flow control, a port driver calls this function to indicate TX + * is available again. + */ +void wwan_port_txon(struct wwan_port *port); + +/** + * wwan_port_get_drvdata - Retrieve driver data from a WWAN port + * @port: Related WWAN port + */ +void *wwan_port_get_drvdata(struct wwan_port *port); + +#endif /* __WWAN_H */ |