// SPDX-License-Identifier: GPL-2.0-or-later/* *  The Serio abstraction module * *  Copyright (c) 1999-2004 Vojtech Pavlik *  Copyright (c) 2004 Dmitry Torokhov *  Copyright (c) 2003 Daniele Bellucci */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/export.h>#include <linux/stddef.h>#include <linux/module.h>#include <linux/serio.h>#include <linux/errno.h>#include <linux/sched.h>#include <linux/slab.h>#include <linux/workqueue.h>#include <linux/mutex.h> MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");MODULE_DESCRIPTION("Serio abstraction core");MODULE_LICENSE("GPL"); /* * serio_mutex protects entire serio subsystem and is taken every time * serio port or driver registered or unregistered. */static DEFINE_MUTEX(serio_mutex); static LIST_HEAD(serio_list); static void serio_add_port(struct serio *serio);static int serio_reconnect_port(struct serio *serio);static void serio_disconnect_port(struct serio *serio);static void serio_reconnect_subtree(struct serio *serio);static void serio_attach_driver(struct serio_driver *drv); static int serio_connect_driver(struct serio *serio, struct serio_driver *drv){	guard(mutex)(&serio->drv_mutex); 	return drv->connect(serio, drv);} static int serio_reconnect_driver(struct serio *serio){	guard(mutex)(&serio->drv_mutex); 	if (serio->drv && serio->drv->reconnect)		return serio->drv->reconnect(serio); 	return -1;} static void serio_disconnect_driver(struct serio *serio){	guard(mutex)(&serio->drv_mutex); 	if (serio->drv)		serio->drv->disconnect(serio);} static int serio_match_port(const struct serio_device_id *ids, struct serio *serio){	while (ids->type || ids->proto) {		if ((ids->type == SERIO_ANY || ids->type == serio->id.type) &&		    (ids->proto == SERIO_ANY || ids->proto == serio->id.proto) &&		    (ids->extra == SERIO_ANY || ids->extra == serio->id.extra) &&		    (ids->id == SERIO_ANY || ids->id == serio->id.id))			return 1;		ids++;	}	return 0;} /* * Basic serio -> driver core mappings */ static int serio_bind_driver(struct serio *serio, struct serio_driver *drv){	int error; 	if (serio_match_port(drv->id_table, serio)) { 		serio->dev.driver = &drv->driver;		if (serio_connect_driver(serio, drv)) {			serio->dev.driver = NULL;			return -ENODEV;		} 		error = device_bind_driver(&serio->dev);		if (error) {			dev_warn(&serio->dev,				 "device_bind_driver() failed for %s (%s) and %s, error: %d\n",				 serio->phys, serio->name,				 drv->description, error);			serio_disconnect_driver(serio);			serio->dev.driver = NULL;			return error;		}	}	return 0;} static void serio_find_driver(struct serio *serio){	int error; 	error = device_attach(&serio->dev);	if (error < 0 && error != -EPROBE_DEFER)		dev_warn(&serio->dev,			 "device_attach() failed for %s (%s), error: %d\n",			 serio->phys, serio->name, error);}  /* * Serio event processing. */ enum serio_event_type {	SERIO_RESCAN_PORT,	SERIO_RECONNECT_PORT,	SERIO_RECONNECT_SUBTREE,	SERIO_REGISTER_PORT,	SERIO_ATTACH_DRIVER,}; struct serio_event {	enum serio_event_type type;	void *object;	struct module *owner;	struct list_head node;}; static DEFINE_SPINLOCK(serio_event_lock);	/* protects serio_event_list */static LIST_HEAD(serio_event_list); static struct serio_event *serio_get_event(void){	struct serio_event *event = NULL; 	guard(spinlock_irqsave)(&serio_event_lock); 	if (!list_empty(&serio_event_list)) {		event = list_first_entry(&serio_event_list,					 struct serio_event, node);		list_del_init(&event->node);	} 	return event;} static void serio_free_event(struct serio_event *event){	module_put(event->owner);	kfree(event);} static void serio_remove_duplicate_events(void *object,					  enum serio_event_type type){	struct serio_event *e, *next; 	guard(spinlock_irqsave)(&serio_event_lock); 	list_for_each_entry_safe(e, next, &serio_event_list, node) {		if (object == e->object) {			/*			 * If this event is of different type we should not			 * look further - we only suppress duplicate events			 * that were sent back-to-back.			 */			if (type != e->type)				break; 			list_del_init(&e->node);			serio_free_event(e);		}	}} static void serio_handle_event(struct work_struct *work){	struct serio_event *event; 	guard(mutex)(&serio_mutex); 	while ((event = serio_get_event())) { 		switch (event->type) { 		case SERIO_REGISTER_PORT:			serio_add_port(event->object);			break; 		case SERIO_RECONNECT_PORT:			serio_reconnect_port(event->object);			break; 		case SERIO_RESCAN_PORT:			serio_disconnect_port(event->object);			serio_find_driver(event->object);			break; 		case SERIO_RECONNECT_SUBTREE:			serio_reconnect_subtree(event->object);			break; 		case SERIO_ATTACH_DRIVER:			serio_attach_driver(event->object);			break;		} 		serio_remove_duplicate_events(event->object, event->type);		serio_free_event(event);	}} static DECLARE_WORK(serio_event_work, serio_handle_event); static int serio_queue_event(void *object, struct module *owner,			     enum serio_event_type event_type){	struct serio_event *event; 	guard(spinlock_irqsave)(&serio_event_lock); 	/*	 * Scan event list for the other events for the same serio port,	 * starting with the most recent one. If event is the same we	 * do not need add new one. If event is of different type we	 * need to add this event and should not look further because	 * we need to preseve sequence of distinct events.	 */	list_for_each_entry_reverse(event, &serio_event_list, node) {		if (event->object == object) {			if (event->type == event_type)				return 0;			break;		}	} 	event = kmalloc_obj(*event, GFP_ATOMIC);	if (!event) {		pr_err("Not enough memory to queue event %d\n", event_type);		return -ENOMEM;	} 	if (!try_module_get(owner)) {		pr_warn("Can't get module reference, dropping event %d\n",			event_type);		kfree(event);		return -EINVAL;	} 	event->type = event_type;	event->object = object;	event->owner = owner; 	list_add_tail(&event->node, &serio_event_list);	queue_work(system_long_wq, &serio_event_work); 	return 0;} /* * Remove all events that have been submitted for a given * object, be it serio port or driver. */static void serio_remove_pending_events(void *object){	struct serio_event *event, *next; 	guard(spinlock_irqsave)(&serio_event_lock); 	list_for_each_entry_safe(event, next, &serio_event_list, node) {		if (event->object == object) {			list_del_init(&event->node);			serio_free_event(event);		}	}} /* * Locate child serio port (if any) that has not been fully registered yet. * * Children are registered by driver's connect() handler so there can't be a * grandchild pending registration together with a child. */static struct serio *serio_get_pending_child(struct serio *parent){	struct serio_event *event;	struct serio *serio; 	guard(spinlock_irqsave)(&serio_event_lock); 	list_for_each_entry(event, &serio_event_list, node) {		if (event->type == SERIO_REGISTER_PORT) {			serio = event->object;			if (serio->parent == parent)				return serio;		}	} 	return NULL;} /* * Serio port operations */ static ssize_t serio_show_description(struct device *dev, struct device_attribute *attr, char *buf){	struct serio *serio = to_serio_port(dev);	return sprintf(buf, "%s\n", serio->name);} static ssize_t modalias_show(struct device *dev, struct device_attribute *attr, char *buf){	struct serio *serio = to_serio_port(dev); 	return sprintf(buf, "serio:ty%02Xpr%02Xid%02Xex%02X\n",			serio->id.type, serio->id.proto, serio->id.id, serio->id.extra);} static ssize_t type_show(struct device *dev, struct device_attribute *attr, char *buf){	struct serio *serio = to_serio_port(dev);	return sprintf(buf, "%02x\n", serio->id.type);} static ssize_t proto_show(struct device *dev, struct device_attribute *attr, char *buf){	struct serio *serio = to_serio_port(dev);	return sprintf(buf, "%02x\n", serio->id.proto);} static ssize_t id_show(struct device *dev, struct device_attribute *attr, char *buf){	struct serio *serio = to_serio_port(dev);	return sprintf(buf, "%02x\n", serio->id.id);} static ssize_t extra_show(struct device *dev, struct device_attribute *attr, char *buf){	struct serio *serio = to_serio_port(dev);	return sprintf(buf, "%02x\n", serio->id.extra);} static ssize_t drvctl_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count){	struct serio *serio = to_serio_port(dev);	struct device_driver *drv;	int error; 	scoped_cond_guard(mutex_intr, return -EINTR, &serio_mutex) {		if (!strncmp(buf, "none", count)) {			serio_disconnect_port(serio);		} else if (!strncmp(buf, "reconnect", count)) {			serio_reconnect_subtree(serio);		} else if (!strncmp(buf, "rescan", count)) {			serio_disconnect_port(serio);			serio_find_driver(serio);			serio_remove_duplicate_events(serio, SERIO_RESCAN_PORT);		} else if ((drv = driver_find(buf, &serio_bus)) != NULL) {			serio_disconnect_port(serio);			error = serio_bind_driver(serio, to_serio_driver(drv));			serio_remove_duplicate_events(serio, SERIO_RESCAN_PORT);			if (error)				return error;		} else {			return -EINVAL;		}	} 	return count;} static ssize_t serio_show_bind_mode(struct device *dev, struct device_attribute *attr, char *buf){	struct serio *serio = to_serio_port(dev);	return sprintf(buf, "%s\n", serio->manual_bind ? "manual" : "auto");} static ssize_t serio_set_bind_mode(struct device *dev, struct device_attribute *attr, const char *buf, size_t count){	struct serio *serio = to_serio_port(dev);	int retval; 	retval = count;	if (!strncmp(buf, "manual", count)) {		serio->manual_bind = true;	} else if (!strncmp(buf, "auto", count)) {		serio->manual_bind = false;	} else {		retval = -EINVAL;	} 	return retval;} static ssize_t firmware_id_show(struct device *dev, struct device_attribute *attr, char *buf){	struct serio *serio = to_serio_port(dev); 	return sprintf(buf, "%s\n", serio->firmware_id);} static DEVICE_ATTR_RO(type);static DEVICE_ATTR_RO(proto);static DEVICE_ATTR_RO(id);static DEVICE_ATTR_RO(extra); static struct attribute *serio_device_id_attrs[] = {	&dev_attr_type.attr,	&dev_attr_proto.attr,	&dev_attr_id.attr,	&dev_attr_extra.attr,	NULL}; static const struct attribute_group serio_id_attr_group = {	.name	= "id",	.attrs	= serio_device_id_attrs,}; static DEVICE_ATTR_RO(modalias);static DEVICE_ATTR_WO(drvctl);static DEVICE_ATTR(description, S_IRUGO, serio_show_description, NULL);static DEVICE_ATTR(bind_mode, S_IWUSR | S_IRUGO, serio_show_bind_mode, serio_set_bind_mode);static DEVICE_ATTR_RO(firmware_id); static struct attribute *serio_device_attrs[] = {	&dev_attr_modalias.attr,	&dev_attr_description.attr,	&dev_attr_drvctl.attr,	&dev_attr_bind_mode.attr,	&dev_attr_firmware_id.attr,	NULL}; static const struct attribute_group serio_device_attr_group = {	.attrs	= serio_device_attrs,}; static const struct attribute_group *serio_device_attr_groups[] = {	&serio_id_attr_group,	&serio_device_attr_group,	NULL}; static void serio_release_port(struct device *dev){	struct serio *serio = to_serio_port(dev); 	kfree(serio);	module_put(THIS_MODULE);} /* * Prepare serio port for registration. */static void serio_init_port(struct serio *serio){	static atomic_t serio_no = ATOMIC_INIT(-1); 	__module_get(THIS_MODULE); 	INIT_LIST_HEAD(&serio->node);	INIT_LIST_HEAD(&serio->child_node);	INIT_LIST_HEAD(&serio->children);	spin_lock_init(&serio->lock);	mutex_init(&serio->drv_mutex);	device_initialize(&serio->dev);	dev_set_name(&serio->dev, "serio%lu",		     (unsigned long)atomic_inc_return(&serio_no));	serio->dev.bus = &serio_bus;	serio->dev.release = serio_release_port;	serio->dev.groups = serio_device_attr_groups;	if (serio->parent) {		serio->dev.parent = &serio->parent->dev;		serio->depth = serio->parent->depth + 1;	} else		serio->depth = 0;	lockdep_set_subclass(&serio->lock, serio->depth);} /* * Complete serio port registration. * Driver core will attempt to find appropriate driver for the port. */static void serio_add_port(struct serio *serio){	struct serio *parent = serio->parent;	int error; 

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