diff options
Diffstat (limited to 'drivers/w1/w1_int.c')
| -rw-r--r-- | drivers/w1/w1_int.c | 244 |
1 files changed, 244 insertions, 0 deletions
diff --git a/drivers/w1/w1_int.c b/drivers/w1/w1_int.c new file mode 100644 index 0000000000..3a71c5eb2f --- /dev/null +++ b/drivers/w1/w1_int.c @@ -0,0 +1,244 @@ +// 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; + + /* For __w1_remove_master_device to decrement + */ + atomic_set(&dev->refcnt, 1); + + 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); |