/* * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #include <linux/kernel.h> #include <linux/list.h> #include <linux/delay.h> #include <linux/kthread.h> #include <linux/slab.h> #include <linux/sched/signal.h> #include <linux/export.h> #include <linux/moduleparam.h> #include "w1_internal.h" #include "w1_netlink.h" static int w1_search_count = -1; /* Default is continual scan */ module_param_named(search_count, w1_search_count, int, 0); static int w1_enable_pullup = 1; module_param_named(enable_pullup, w1_enable_pullup, int, 0); static struct w1_master *w1_alloc_dev(u32 id, int slave_count, int slave_ttl, struct device_driver *driver, struct device *device) { struct w1_master *dev; int err; /* * We are in process context(kernel thread), so can sleep. */ dev = kzalloc(sizeof(struct w1_master) + sizeof(struct w1_bus_master), GFP_KERNEL); if (!dev) { pr_err("Failed to allocate %zd bytes for new w1 device.\n", sizeof(struct w1_master)); return NULL; } dev->bus_master = (struct w1_bus_master *)(dev + 1); dev->owner = THIS_MODULE; dev->max_slave_count = slave_count; dev->slave_count = 0; dev->attempts = 0; dev->initialized = 0; dev->id = id; dev->slave_ttl = slave_ttl; dev->search_count = w1_search_count; dev->enable_pullup = w1_enable_pullup; /* 1 for w1_process to decrement * 1 for __w1_remove_master_device to decrement */ atomic_set(&dev->refcnt, 2); INIT_LIST_HEAD(&dev->slist); INIT_LIST_HEAD(&dev->async_list); mutex_init(&dev->mutex); mutex_init(&dev->bus_mutex); mutex_init(&dev->list_mutex); memcpy(&dev->dev, device, sizeof(struct device)); dev_set_name(&dev->dev, "w1_bus_master%u", dev->id); snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id); dev->dev.init_name = dev->name; dev->driver = driver; dev->seq = 1; err = device_register(&dev->dev); if (err) { pr_err("Failed to register master device. err=%d\n", err); put_device(&dev->dev); dev = NULL; } return dev; } static void w1_free_dev(struct w1_master *dev) { device_unregister(&dev->dev); } /** * w1_add_master_device() - registers a new master device * @master: master bus device to register */ int w1_add_master_device(struct w1_bus_master *master) { struct w1_master *dev, *entry; int retval = 0; struct w1_netlink_msg msg; int id, found; /* validate minimum functionality */ if (!(master->touch_bit && master->reset_bus) && !(master->write_bit && master->read_bit) && !(master->write_byte && master->read_byte && master->reset_bus)) { pr_err("w1_add_master_device: invalid function set\n"); return(-EINVAL); } /* Lock until the device is added (or not) to w1_masters. */ mutex_lock(&w1_mlock); /* Search for the first available id (starting at 1). */ id = 0; do { ++id; found = 0; list_for_each_entry(entry, &w1_masters, w1_master_entry) { if (entry->id == id) { found = 1; break; } } } while (found); dev = w1_alloc_dev(id, w1_max_slave_count, w1_max_slave_ttl, &w1_master_driver, &w1_master_device); if (!dev) { mutex_unlock(&w1_mlock); return -ENOMEM; } retval = w1_create_master_attributes(dev); if (retval) { mutex_unlock(&w1_mlock); goto err_out_free_dev; } memcpy(dev->bus_master, master, sizeof(struct w1_bus_master)); dev->initialized = 1; dev->thread = kthread_run(&w1_process, dev, "%s", dev->name); if (IS_ERR(dev->thread)) { retval = PTR_ERR(dev->thread); dev_err(&dev->dev, "Failed to create new kernel thread. err=%d\n", retval); mutex_unlock(&w1_mlock); goto err_out_rm_attr; } list_add(&dev->w1_master_entry, &w1_masters); mutex_unlock(&w1_mlock); memset(&msg, 0, sizeof(msg)); msg.id.mst.id = dev->id; msg.type = W1_MASTER_ADD; w1_netlink_send(dev, &msg); return 0; #if 0 /* Thread cleanup code, not required currently. */ err_out_kill_thread: set_bit(W1_ABORT_SEARCH, &dev->flags); kthread_stop(dev->thread); #endif err_out_rm_attr: w1_destroy_master_attributes(dev); err_out_free_dev: w1_free_dev(dev); return retval; } EXPORT_SYMBOL(w1_add_master_device); void __w1_remove_master_device(struct w1_master *dev) { struct w1_netlink_msg msg; struct w1_slave *sl, *sln; mutex_lock(&w1_mlock); list_del(&dev->w1_master_entry); mutex_unlock(&w1_mlock); set_bit(W1_ABORT_SEARCH, &dev->flags); kthread_stop(dev->thread); mutex_lock(&dev->mutex); mutex_lock(&dev->list_mutex); list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) { mutex_unlock(&dev->list_mutex); w1_slave_detach(sl); mutex_lock(&dev->list_mutex); } w1_destroy_master_attributes(dev); mutex_unlock(&dev->list_mutex); mutex_unlock(&dev->mutex); atomic_dec(&dev->refcnt); while (atomic_read(&dev->refcnt)) { dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n", dev->name, atomic_read(&dev->refcnt)); if (msleep_interruptible(1000)) flush_signals(current); mutex_lock(&dev->list_mutex); w1_process_callbacks(dev); mutex_unlock(&dev->list_mutex); } mutex_lock(&dev->list_mutex); w1_process_callbacks(dev); mutex_unlock(&dev->list_mutex); memset(&msg, 0, sizeof(msg)); msg.id.mst.id = dev->id; msg.type = W1_MASTER_REMOVE; w1_netlink_send(dev, &msg); w1_free_dev(dev); } /** * w1_remove_master_device() - unregister a master device * @bm: master bus device to remove */ void w1_remove_master_device(struct w1_bus_master *bm) { struct w1_master *dev, *found = NULL; list_for_each_entry(dev, &w1_masters, w1_master_entry) { if (!dev->initialized) continue; if (dev->bus_master->data == bm->data) { found = dev; break; } } if (!found) { pr_err("Device doesn't exist.\n"); return; } __w1_remove_master_device(found); } EXPORT_SYMBOL(w1_remove_master_device);