// SPDX-License-Identifier: GPL-2.0 /* * Tty port functions */ #include <linux/types.h> #include <linux/errno.h> #include <linux/tty.h> #include <linux/tty_driver.h> #include <linux/tty_flip.h> #include <linux/serial.h> #include <linux/timer.h> #include <linux/string.h> #include <linux/slab.h> #include <linux/sched/signal.h> #include <linux/wait.h> #include <linux/bitops.h> #include <linux/delay.h> #include <linux/module.h> #include <linux/serdev.h> #include "tty.h" static size_t tty_port_default_receive_buf(struct tty_port *port, const u8 *p, const u8 *f, size_t count) { … } static void tty_port_default_lookahead_buf(struct tty_port *port, const u8 *p, const u8 *f, size_t count) { … } static void tty_port_default_wakeup(struct tty_port *port) { … } const struct tty_port_client_operations tty_port_default_client_ops = …; EXPORT_SYMBOL_GPL(…); /** * tty_port_init - initialize tty_port * @port: tty_port to initialize * * Initializes the state of struct tty_port. When a port was initialized using * this function, one has to destroy the port by tty_port_destroy(). Either * indirectly by using &tty_port refcounting (tty_port_put()) or directly if * refcounting is not used. */ void tty_port_init(struct tty_port *port) { … } EXPORT_SYMBOL(…); /** * tty_port_link_device - link tty and tty_port * @port: tty_port of the device * @driver: tty_driver for this device * @index: index of the tty * * Provide the tty layer with a link from a tty (specified by @index) to a * tty_port (@port). Use this only if neither tty_port_register_device() nor * tty_port_install() is used in the driver. If used, this has to be called * before tty_register_driver(). */ void tty_port_link_device(struct tty_port *port, struct tty_driver *driver, unsigned index) { … } EXPORT_SYMBOL_GPL(…); /** * tty_port_register_device - register tty device * @port: tty_port of the device * @driver: tty_driver for this device * @index: index of the tty * @device: parent if exists, otherwise NULL * * It is the same as tty_register_device() except the provided @port is linked * to a concrete tty specified by @index. Use this or tty_port_install() (or * both). Call tty_port_link_device() as a last resort. */ struct device *tty_port_register_device(struct tty_port *port, struct tty_driver *driver, unsigned index, struct device *device) { … } EXPORT_SYMBOL_GPL(…); /** * tty_port_register_device_attr - register tty device * @port: tty_port of the device * @driver: tty_driver for this device * @index: index of the tty * @device: parent if exists, otherwise NULL * @drvdata: Driver data to be set to device. * @attr_grp: Attribute group to be set on device. * * It is the same as tty_register_device_attr() except the provided @port is * linked to a concrete tty specified by @index. Use this or tty_port_install() * (or both). Call tty_port_link_device() as a last resort. */ struct device *tty_port_register_device_attr(struct tty_port *port, struct tty_driver *driver, unsigned index, struct device *device, void *drvdata, const struct attribute_group **attr_grp) { … } EXPORT_SYMBOL_GPL(…); /** * tty_port_register_device_attr_serdev - register tty or serdev device * @port: tty_port of the device * @driver: tty_driver for this device * @index: index of the tty * @host: serial port hardware device * @parent: parent if exists, otherwise NULL * @drvdata: driver data for the device * @attr_grp: attribute group for the device * * Register a serdev or tty device depending on if the parent device has any * defined serdev clients or not. */ struct device *tty_port_register_device_attr_serdev(struct tty_port *port, struct tty_driver *driver, unsigned index, struct device *host, struct device *parent, void *drvdata, const struct attribute_group **attr_grp) { … } EXPORT_SYMBOL_GPL(…); /** * tty_port_register_device_serdev - register tty or serdev device * @port: tty_port of the device * @driver: tty_driver for this device * @index: index of the tty * @host: serial port hardware controller device * @parent: parent if exists, otherwise NULL * * Register a serdev or tty device depending on if the parent device has any * defined serdev clients or not. */ struct device *tty_port_register_device_serdev(struct tty_port *port, struct tty_driver *driver, unsigned index, struct device *host, struct device *parent) { … } EXPORT_SYMBOL_GPL(…); /** * tty_port_unregister_device - deregister a tty or serdev device * @port: tty_port of the device * @driver: tty_driver for this device * @index: index of the tty * * If a tty or serdev device is registered with a call to * tty_port_register_device_serdev() then this function must be called when * the device is gone. */ void tty_port_unregister_device(struct tty_port *port, struct tty_driver *driver, unsigned index) { … } EXPORT_SYMBOL_GPL(…); int tty_port_alloc_xmit_buf(struct tty_port *port) { … } EXPORT_SYMBOL(…); void tty_port_free_xmit_buf(struct tty_port *port) { … } EXPORT_SYMBOL(…); /** * tty_port_destroy - destroy inited port * @port: tty port to be destroyed * * When a port was initialized using tty_port_init(), one has to destroy the * port by this function. Either indirectly by using &tty_port refcounting * (tty_port_put()) or directly if refcounting is not used. */ void tty_port_destroy(struct tty_port *port) { … } EXPORT_SYMBOL(…); static void tty_port_destructor(struct kref *kref) { … } /** * tty_port_put - drop a reference to tty_port * @port: port to drop a reference of (can be NULL) * * The final put will destroy and free up the @port using * @port->ops->destruct() hook, or using kfree() if not provided. */ void tty_port_put(struct tty_port *port) { … } EXPORT_SYMBOL(…); /** * tty_port_tty_get - get a tty reference * @port: tty port * * Return a refcount protected tty instance or %NULL if the port is not * associated with a tty (eg due to close or hangup). */ struct tty_struct *tty_port_tty_get(struct tty_port *port) { … } EXPORT_SYMBOL(…); /** * tty_port_tty_set - set the tty of a port * @port: tty port * @tty: the tty * * Associate the port and tty pair. Manages any internal refcounts. Pass %NULL * to deassociate a port. */ void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty) { … } EXPORT_SYMBOL(…); /** * tty_port_shutdown - internal helper to shutdown the device * @port: tty port to be shut down * @tty: the associated tty * * It is used by tty_port_hangup() and tty_port_close(). Its task is to * shutdown the device if it was initialized (note consoles remain * functioning). It lowers DTR/RTS (if @tty has HUPCL set) and invokes * @port->ops->shutdown(). */ static void tty_port_shutdown(struct tty_port *port, struct tty_struct *tty) { … } /** * tty_port_hangup - hangup helper * @port: tty port * * Perform port level tty hangup flag and count changes. Drop the tty * reference. * * Caller holds tty lock. */ void tty_port_hangup(struct tty_port *port) { … } EXPORT_SYMBOL(…); /** * tty_port_tty_hangup - helper to hang up a tty * @port: tty port * @check_clocal: hang only ttys with %CLOCAL unset? */ void tty_port_tty_hangup(struct tty_port *port, bool check_clocal) { … } EXPORT_SYMBOL_GPL(…); /** * tty_port_tty_wakeup - helper to wake up a tty * @port: tty port */ void tty_port_tty_wakeup(struct tty_port *port) { … } EXPORT_SYMBOL_GPL(…); /** * tty_port_carrier_raised - carrier raised check * @port: tty port * * Wrapper for the carrier detect logic. For the moment this is used * to hide some internal details. This will eventually become entirely * internal to the tty port. */ bool tty_port_carrier_raised(struct tty_port *port) { … } EXPORT_SYMBOL(…); /** * tty_port_raise_dtr_rts - Raise DTR/RTS * @port: tty port * * Wrapper for the DTR/RTS raise logic. For the moment this is used to hide * some internal details. This will eventually become entirely internal to the * tty port. */ void tty_port_raise_dtr_rts(struct tty_port *port) { … } EXPORT_SYMBOL(…); /** * tty_port_lower_dtr_rts - Lower DTR/RTS * @port: tty port * * Wrapper for the DTR/RTS raise logic. For the moment this is used to hide * some internal details. This will eventually become entirely internal to the * tty port. */ void tty_port_lower_dtr_rts(struct tty_port *port) { … } EXPORT_SYMBOL(…); /** * tty_port_block_til_ready - Waiting logic for tty open * @port: the tty port being opened * @tty: the tty device being bound * @filp: the file pointer of the opener or %NULL * * Implement the core POSIX/SuS tty behaviour when opening a tty device. * Handles: * * - hangup (both before and during) * - non blocking open * - rts/dtr/dcd * - signals * - port flags and counts * * The passed @port must implement the @port->ops->carrier_raised method if it * can do carrier detect and the @port->ops->dtr_rts method if it supports * software management of these lines. Note that the dtr/rts raise is done each * iteration as a hangup may have previously dropped them while we wait. * * Caller holds tty lock. * * Note: May drop and reacquire tty lock when blocking, so @tty and @port may * have changed state (eg., may have been hung up). */ int tty_port_block_til_ready(struct tty_port *port, struct tty_struct *tty, struct file *filp) { … } EXPORT_SYMBOL(…); static void tty_port_drain_delay(struct tty_port *port, struct tty_struct *tty) { … } /** * tty_port_close_start - helper for tty->ops->close, part 1/2 * @port: tty_port of the device * @tty: tty being closed * @filp: passed file pointer * * Decrements and checks open count. Flushes the port if this is the last * close. That means, dropping the data from the outpu buffer on the device and * waiting for sending logic to finish. The rest of close handling is performed * in tty_port_close_end(). * * Locking: Caller holds tty lock. * * Return: 1 if this is the last close, otherwise 0 */ int tty_port_close_start(struct tty_port *port, struct tty_struct *tty, struct file *filp) { … } EXPORT_SYMBOL(…); /** * tty_port_close_end - helper for tty->ops->close, part 2/2 * @port: tty_port of the device * @tty: tty being closed * * This is a continuation of the first part: tty_port_close_start(). This * should be called after turning off the device. It flushes the data from the * line discipline and delays the close by @port->close_delay. * * Locking: Caller holds tty lock. */ void tty_port_close_end(struct tty_port *port, struct tty_struct *tty) { … } EXPORT_SYMBOL(…); /** * tty_port_close - generic tty->ops->close handler * @port: tty_port of the device * @tty: tty being closed * @filp: passed file pointer * * It is a generic helper to be used in driver's @tty->ops->close. It wraps a * sequence of tty_port_close_start(), tty_port_shutdown(), and * tty_port_close_end(). The latter two are called only if this is the last * close. See the respective functions for the details. * * Locking: Caller holds tty lock */ void tty_port_close(struct tty_port *port, struct tty_struct *tty, struct file *filp) { … } EXPORT_SYMBOL(…); /** * tty_port_install - generic tty->ops->install handler * @port: tty_port of the device * @driver: tty_driver for this device * @tty: tty to be installed * * It is the same as tty_standard_install() except the provided @port is linked * to a concrete tty specified by @tty. Use this or tty_port_register_device() * (or both). Call tty_port_link_device() as a last resort. */ int tty_port_install(struct tty_port *port, struct tty_driver *driver, struct tty_struct *tty) { … } EXPORT_SYMBOL_GPL(…); /** * tty_port_open - generic tty->ops->open handler * @port: tty_port of the device * @tty: tty to be opened * @filp: passed file pointer * * It is a generic helper to be used in driver's @tty->ops->open. It activates * the devices using @port->ops->activate if not active already. And waits for * the device to be ready using tty_port_block_til_ready() (e.g. raises * DTR/CTS and waits for carrier). * * Note that @port->ops->shutdown is not called when @port->ops->activate * returns an error (on the contrary, @tty->ops->close is). * * Locking: Caller holds tty lock. * * Note: may drop and reacquire tty lock (in tty_port_block_til_ready()) so * @tty and @port may have changed state (eg., may be hung up now). */ int tty_port_open(struct tty_port *port, struct tty_struct *tty, struct file *filp) { … } EXPORT_SYMBOL(…);
Codebase Browser
linux