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- // SPDX-License-Identifier: GPL-2.0-or-later
- /*
- * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
- */
- #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);
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