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245 lines
5.7 KiB
245 lines
5.7 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Copyright (c) 2004 Evgeniy Polyakov <[email protected]> |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/list.h> |
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#include <linux/delay.h> |
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#include <linux/kthread.h> |
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#include <linux/slab.h> |
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#include <linux/sched/signal.h> |
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#include <linux/export.h> |
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#include <linux/moduleparam.h> |
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#include "w1_internal.h" |
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#include "w1_netlink.h" |
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static int w1_search_count = -1; /* Default is continual scan */ |
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module_param_named(search_count, w1_search_count, int, 0); |
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static int w1_enable_pullup = 1; |
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module_param_named(enable_pullup, w1_enable_pullup, int, 0); |
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static struct w1_master *w1_alloc_dev(u32 id, int slave_count, int slave_ttl, |
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struct device_driver *driver, |
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struct device *device) |
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{ |
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struct w1_master *dev; |
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int err; |
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/* |
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* We are in process context(kernel thread), so can sleep. |
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*/ |
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dev = kzalloc(sizeof(struct w1_master) + sizeof(struct w1_bus_master), GFP_KERNEL); |
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if (!dev) { |
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pr_err("Failed to allocate %zd bytes for new w1 device.\n", |
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sizeof(struct w1_master)); |
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return NULL; |
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} |
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dev->bus_master = (struct w1_bus_master *)(dev + 1); |
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dev->owner = THIS_MODULE; |
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dev->max_slave_count = slave_count; |
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dev->slave_count = 0; |
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dev->attempts = 0; |
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dev->initialized = 0; |
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dev->id = id; |
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dev->slave_ttl = slave_ttl; |
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dev->search_count = w1_search_count; |
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dev->enable_pullup = w1_enable_pullup; |
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/* 1 for w1_process to decrement |
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* 1 for __w1_remove_master_device to decrement |
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*/ |
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atomic_set(&dev->refcnt, 2); |
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INIT_LIST_HEAD(&dev->slist); |
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INIT_LIST_HEAD(&dev->async_list); |
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mutex_init(&dev->mutex); |
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mutex_init(&dev->bus_mutex); |
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mutex_init(&dev->list_mutex); |
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memcpy(&dev->dev, device, sizeof(struct device)); |
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dev_set_name(&dev->dev, "w1_bus_master%u", dev->id); |
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snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id); |
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dev->dev.init_name = dev->name; |
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dev->driver = driver; |
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dev->seq = 1; |
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err = device_register(&dev->dev); |
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if (err) { |
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pr_err("Failed to register master device. err=%d\n", err); |
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put_device(&dev->dev); |
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dev = NULL; |
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} |
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return dev; |
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} |
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static void w1_free_dev(struct w1_master *dev) |
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{ |
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device_unregister(&dev->dev); |
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} |
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/** |
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* w1_add_master_device() - registers a new master device |
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* @master: master bus device to register |
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*/ |
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int w1_add_master_device(struct w1_bus_master *master) |
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{ |
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struct w1_master *dev, *entry; |
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int retval = 0; |
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struct w1_netlink_msg msg; |
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int id, found; |
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/* validate minimum functionality */ |
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if (!(master->touch_bit && master->reset_bus) && |
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!(master->write_bit && master->read_bit) && |
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!(master->write_byte && master->read_byte && master->reset_bus)) { |
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pr_err("w1_add_master_device: invalid function set\n"); |
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return(-EINVAL); |
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} |
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/* Lock until the device is added (or not) to w1_masters. */ |
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mutex_lock(&w1_mlock); |
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/* Search for the first available id (starting at 1). */ |
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id = 0; |
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do { |
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++id; |
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found = 0; |
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list_for_each_entry(entry, &w1_masters, w1_master_entry) { |
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if (entry->id == id) { |
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found = 1; |
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break; |
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} |
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} |
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} while (found); |
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dev = w1_alloc_dev(id, w1_max_slave_count, w1_max_slave_ttl, |
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&w1_master_driver, &w1_master_device); |
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if (!dev) { |
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mutex_unlock(&w1_mlock); |
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return -ENOMEM; |
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} |
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retval = w1_create_master_attributes(dev); |
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if (retval) { |
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mutex_unlock(&w1_mlock); |
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goto err_out_free_dev; |
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} |
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memcpy(dev->bus_master, master, sizeof(struct w1_bus_master)); |
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dev->initialized = 1; |
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dev->thread = kthread_run(&w1_process, dev, "%s", dev->name); |
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if (IS_ERR(dev->thread)) { |
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retval = PTR_ERR(dev->thread); |
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dev_err(&dev->dev, |
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"Failed to create new kernel thread. err=%d\n", |
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retval); |
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mutex_unlock(&w1_mlock); |
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goto err_out_rm_attr; |
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} |
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list_add(&dev->w1_master_entry, &w1_masters); |
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mutex_unlock(&w1_mlock); |
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memset(&msg, 0, sizeof(msg)); |
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msg.id.mst.id = dev->id; |
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msg.type = W1_MASTER_ADD; |
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w1_netlink_send(dev, &msg); |
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return 0; |
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#if 0 /* Thread cleanup code, not required currently. */ |
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err_out_kill_thread: |
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set_bit(W1_ABORT_SEARCH, &dev->flags); |
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kthread_stop(dev->thread); |
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#endif |
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err_out_rm_attr: |
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w1_destroy_master_attributes(dev); |
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err_out_free_dev: |
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w1_free_dev(dev); |
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return retval; |
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} |
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EXPORT_SYMBOL(w1_add_master_device); |
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void __w1_remove_master_device(struct w1_master *dev) |
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{ |
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struct w1_netlink_msg msg; |
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struct w1_slave *sl, *sln; |
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mutex_lock(&w1_mlock); |
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list_del(&dev->w1_master_entry); |
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mutex_unlock(&w1_mlock); |
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set_bit(W1_ABORT_SEARCH, &dev->flags); |
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kthread_stop(dev->thread); |
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mutex_lock(&dev->mutex); |
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mutex_lock(&dev->list_mutex); |
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list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) { |
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mutex_unlock(&dev->list_mutex); |
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w1_slave_detach(sl); |
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mutex_lock(&dev->list_mutex); |
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} |
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w1_destroy_master_attributes(dev); |
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mutex_unlock(&dev->list_mutex); |
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mutex_unlock(&dev->mutex); |
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atomic_dec(&dev->refcnt); |
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while (atomic_read(&dev->refcnt)) { |
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dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n", |
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dev->name, atomic_read(&dev->refcnt)); |
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if (msleep_interruptible(1000)) |
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flush_signals(current); |
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mutex_lock(&dev->list_mutex); |
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w1_process_callbacks(dev); |
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mutex_unlock(&dev->list_mutex); |
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} |
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mutex_lock(&dev->list_mutex); |
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w1_process_callbacks(dev); |
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mutex_unlock(&dev->list_mutex); |
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memset(&msg, 0, sizeof(msg)); |
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msg.id.mst.id = dev->id; |
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msg.type = W1_MASTER_REMOVE; |
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w1_netlink_send(dev, &msg); |
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w1_free_dev(dev); |
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} |
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/** |
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* w1_remove_master_device() - unregister a master device |
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* @bm: master bus device to remove |
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*/ |
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void w1_remove_master_device(struct w1_bus_master *bm) |
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{ |
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struct w1_master *dev, *found = NULL; |
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list_for_each_entry(dev, &w1_masters, w1_master_entry) { |
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if (!dev->initialized) |
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continue; |
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if (dev->bus_master->data == bm->data) { |
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found = dev; |
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break; |
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} |
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} |
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if (!found) { |
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pr_err("Device doesn't exist.\n"); |
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return; |
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} |
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__w1_remove_master_device(found); |
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} |
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EXPORT_SYMBOL(w1_remove_master_device);
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