1c942fddfSThomas Gleixner // SPDX-License-Identifier: GPL-2.0-or-later
21da177e4SLinus Torvalds /*
3a8018766SEvgeniy Polyakov * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
41da177e4SLinus Torvalds */
51da177e4SLinus Torvalds
61da177e4SLinus Torvalds #include <linux/kernel.h>
71da177e4SLinus Torvalds #include <linux/list.h>
81da177e4SLinus Torvalds #include <linux/delay.h>
9674a396cSEvgeniy Polyakov #include <linux/kthread.h>
105a0e3ad6STejun Heo #include <linux/slab.h>
113f07c014SIngo Molnar #include <linux/sched/signal.h>
129623932cSPaul Gortmaker #include <linux/export.h>
134d184129SPaul Gortmaker #include <linux/moduleparam.h>
141da177e4SLinus Torvalds
15de0d6dbdSAndrew F. Davis #include "w1_internal.h"
161da177e4SLinus Torvalds #include "w1_netlink.h"
171da177e4SLinus Torvalds
189141f57cSDavid Fries static int w1_search_count = -1; /* Default is continual scan */
199141f57cSDavid Fries module_param_named(search_count, w1_search_count, int, 0);
201da177e4SLinus Torvalds
216a158c0dSDavid Fries static int w1_enable_pullup = 1;
226a158c0dSDavid Fries module_param_named(enable_pullup, w1_enable_pullup, int, 0);
236a158c0dSDavid Fries
w1_alloc_dev(u32 id,int slave_count,int slave_ttl,struct device_driver * driver,struct device * device)247785925dSEvgeniy Polyakov static struct w1_master *w1_alloc_dev(u32 id, int slave_count, int slave_ttl,
257785925dSEvgeniy Polyakov struct device_driver *driver,
267785925dSEvgeniy Polyakov struct device *device)
271da177e4SLinus Torvalds {
281da177e4SLinus Torvalds struct w1_master *dev;
291da177e4SLinus Torvalds int err;
301da177e4SLinus Torvalds
311da177e4SLinus Torvalds /*
321da177e4SLinus Torvalds * We are in process context(kernel thread), so can sleep.
331da177e4SLinus Torvalds */
34dd00cc48SYoann Padioleau dev = kzalloc(sizeof(struct w1_master) + sizeof(struct w1_bus_master), GFP_KERNEL);
351da177e4SLinus Torvalds if (!dev) {
36fdc9167aSFjodor Schelichow pr_err("Failed to allocate %zd bytes for new w1 device.\n",
371da177e4SLinus Torvalds sizeof(struct w1_master));
381da177e4SLinus Torvalds return NULL;
391da177e4SLinus Torvalds }
401da177e4SLinus Torvalds
411da177e4SLinus Torvalds
421da177e4SLinus Torvalds dev->bus_master = (struct w1_bus_master *)(dev + 1);
431da177e4SLinus Torvalds
441da177e4SLinus Torvalds dev->owner = THIS_MODULE;
451da177e4SLinus Torvalds dev->max_slave_count = slave_count;
461da177e4SLinus Torvalds dev->slave_count = 0;
471da177e4SLinus Torvalds dev->attempts = 0;
481da177e4SLinus Torvalds dev->initialized = 0;
491da177e4SLinus Torvalds dev->id = id;
501da177e4SLinus Torvalds dev->slave_ttl = slave_ttl;
519141f57cSDavid Fries dev->search_count = w1_search_count;
526a158c0dSDavid Fries dev->enable_pullup = w1_enable_pullup;
531da177e4SLinus Torvalds
54*25d56488SYang Yingliang /* For __w1_remove_master_device to decrement
5501e14d6dSDavid Fries */
56*25d56488SYang Yingliang atomic_set(&dev->refcnt, 1);
571da177e4SLinus Torvalds
581da177e4SLinus Torvalds INIT_LIST_HEAD(&dev->slist);
599fcbbac5SDavid Fries INIT_LIST_HEAD(&dev->async_list);
60abd52a13SEvgeniy Polyakov mutex_init(&dev->mutex);
61b02f8bedSNeilBrown mutex_init(&dev->bus_mutex);
629fcbbac5SDavid Fries mutex_init(&dev->list_mutex);
631da177e4SLinus Torvalds
641da177e4SLinus Torvalds memcpy(&dev->dev, device, sizeof(struct device));
6540f91de6SKay Sievers dev_set_name(&dev->dev, "w1_bus_master%u", dev->id);
661da177e4SLinus Torvalds snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id);
6768a436aeSFlorian Faber dev->dev.init_name = dev->name;
681da177e4SLinus Torvalds
691da177e4SLinus Torvalds dev->driver = driver;
701da177e4SLinus Torvalds
711da177e4SLinus Torvalds dev->seq = 1;
721da177e4SLinus Torvalds
731da177e4SLinus Torvalds err = device_register(&dev->dev);
741da177e4SLinus Torvalds if (err) {
75fdc9167aSFjodor Schelichow pr_err("Failed to register master device. err=%d\n", err);
765052436dSLevente Kurusa put_device(&dev->dev);
771da177e4SLinus Torvalds dev = NULL;
781da177e4SLinus Torvalds }
791da177e4SLinus Torvalds
801da177e4SLinus Torvalds return dev;
811da177e4SLinus Torvalds }
821da177e4SLinus Torvalds
w1_free_dev(struct w1_master * dev)832c5bfdacSEvgeniy Polyakov static void w1_free_dev(struct w1_master *dev)
841da177e4SLinus Torvalds {
851da177e4SLinus Torvalds device_unregister(&dev->dev);
861da177e4SLinus Torvalds }
871da177e4SLinus Torvalds
88b3be177aSDavid Fries /**
89b3be177aSDavid Fries * w1_add_master_device() - registers a new master device
90b3be177aSDavid Fries * @master: master bus device to register
91b3be177aSDavid Fries */
w1_add_master_device(struct w1_bus_master * master)921da177e4SLinus Torvalds int w1_add_master_device(struct w1_bus_master *master)
931da177e4SLinus Torvalds {
94af00a2d5SDavid Fries struct w1_master *dev, *entry;
951da177e4SLinus Torvalds int retval = 0;
961da177e4SLinus Torvalds struct w1_netlink_msg msg;
97af00a2d5SDavid Fries int id, found;
981da177e4SLinus Torvalds
99be57ce26SEvgeniy Polyakov /* validate minimum functionality */
100be57ce26SEvgeniy Polyakov if (!(master->touch_bit && master->reset_bus) &&
101c1f858b7SEvgeniy Polyakov !(master->write_bit && master->read_bit) &&
102c1f858b7SEvgeniy Polyakov !(master->write_byte && master->read_byte && master->reset_bus)) {
103fdc9167aSFjodor Schelichow pr_err("w1_add_master_device: invalid function set\n");
104be57ce26SEvgeniy Polyakov return(-EINVAL);
105be57ce26SEvgeniy Polyakov }
106be57ce26SEvgeniy Polyakov
107af00a2d5SDavid Fries /* Lock until the device is added (or not) to w1_masters. */
108af00a2d5SDavid Fries mutex_lock(&w1_mlock);
109af00a2d5SDavid Fries /* Search for the first available id (starting at 1). */
110af00a2d5SDavid Fries id = 0;
111af00a2d5SDavid Fries do {
112af00a2d5SDavid Fries ++id;
113af00a2d5SDavid Fries found = 0;
114af00a2d5SDavid Fries list_for_each_entry(entry, &w1_masters, w1_master_entry) {
115af00a2d5SDavid Fries if (entry->id == id) {
116af00a2d5SDavid Fries found = 1;
117af00a2d5SDavid Fries break;
118af00a2d5SDavid Fries }
119af00a2d5SDavid Fries }
120af00a2d5SDavid Fries } while (found);
121af00a2d5SDavid Fries
122af00a2d5SDavid Fries dev = w1_alloc_dev(id, w1_max_slave_count, w1_max_slave_ttl,
123af00a2d5SDavid Fries &w1_master_driver, &w1_master_device);
124af00a2d5SDavid Fries if (!dev) {
125af00a2d5SDavid Fries mutex_unlock(&w1_mlock);
1261da177e4SLinus Torvalds return -ENOMEM;
127af00a2d5SDavid Fries }
1281da177e4SLinus Torvalds
12901e14d6dSDavid Fries retval = w1_create_master_attributes(dev);
130af00a2d5SDavid Fries if (retval) {
131af00a2d5SDavid Fries mutex_unlock(&w1_mlock);
13201e14d6dSDavid Fries goto err_out_free_dev;
133af00a2d5SDavid Fries }
13401e14d6dSDavid Fries
13501e14d6dSDavid Fries memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));
13601e14d6dSDavid Fries
13701e14d6dSDavid Fries dev->initialized = 1;
13801e14d6dSDavid Fries
139674a396cSEvgeniy Polyakov dev->thread = kthread_run(&w1_process, dev, "%s", dev->name);
140674a396cSEvgeniy Polyakov if (IS_ERR(dev->thread)) {
141674a396cSEvgeniy Polyakov retval = PTR_ERR(dev->thread);
1421da177e4SLinus Torvalds dev_err(&dev->dev,
1431da177e4SLinus Torvalds "Failed to create new kernel thread. err=%d\n",
144674a396cSEvgeniy Polyakov retval);
145af00a2d5SDavid Fries mutex_unlock(&w1_mlock);
14601e14d6dSDavid Fries goto err_out_rm_attr;
1471da177e4SLinus Torvalds }
1481da177e4SLinus Torvalds
1491da177e4SLinus Torvalds list_add(&dev->w1_master_entry, &w1_masters);
150abd52a13SEvgeniy Polyakov mutex_unlock(&w1_mlock);
1511da177e4SLinus Torvalds
15212003375SEvgeniy Polyakov memset(&msg, 0, sizeof(msg));
1531da177e4SLinus Torvalds msg.id.mst.id = dev->id;
1541da177e4SLinus Torvalds msg.type = W1_MASTER_ADD;
1551da177e4SLinus Torvalds w1_netlink_send(dev, &msg);
1561da177e4SLinus Torvalds
1571da177e4SLinus Torvalds return 0;
1581da177e4SLinus Torvalds
15901e14d6dSDavid Fries #if 0 /* Thread cleanup code, not required currently. */
1601da177e4SLinus Torvalds err_out_kill_thread:
16142105698SDavid Fries set_bit(W1_ABORT_SEARCH, &dev->flags);
162674a396cSEvgeniy Polyakov kthread_stop(dev->thread);
16301e14d6dSDavid Fries #endif
16401e14d6dSDavid Fries err_out_rm_attr:
16501e14d6dSDavid Fries w1_destroy_master_attributes(dev);
1661da177e4SLinus Torvalds err_out_free_dev:
1671da177e4SLinus Torvalds w1_free_dev(dev);
1681da177e4SLinus Torvalds
1691da177e4SLinus Torvalds return retval;
1701da177e4SLinus Torvalds }
17150fa2951SAndrew F. Davis EXPORT_SYMBOL(w1_add_master_device);
1721da177e4SLinus Torvalds
__w1_remove_master_device(struct w1_master * dev)1731da177e4SLinus Torvalds void __w1_remove_master_device(struct w1_master *dev)
1741da177e4SLinus Torvalds {
1751da177e4SLinus Torvalds struct w1_netlink_msg msg;
176c30c9b15SDavid Fries struct w1_slave *sl, *sln;
1771da177e4SLinus Torvalds
178c30c9b15SDavid Fries mutex_lock(&w1_mlock);
179c30c9b15SDavid Fries list_del(&dev->w1_master_entry);
180c30c9b15SDavid Fries mutex_unlock(&w1_mlock);
181c30c9b15SDavid Fries
1829fcbbac5SDavid Fries set_bit(W1_ABORT_SEARCH, &dev->flags);
1839fcbbac5SDavid Fries kthread_stop(dev->thread);
1849fcbbac5SDavid Fries
185c30c9b15SDavid Fries mutex_lock(&dev->mutex);
1869fcbbac5SDavid Fries mutex_lock(&dev->list_mutex);
1879fcbbac5SDavid Fries list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
1889fcbbac5SDavid Fries mutex_unlock(&dev->list_mutex);
189c30c9b15SDavid Fries w1_slave_detach(sl);
1909fcbbac5SDavid Fries mutex_lock(&dev->list_mutex);
1919fcbbac5SDavid Fries }
192c30c9b15SDavid Fries w1_destroy_master_attributes(dev);
1939fcbbac5SDavid Fries mutex_unlock(&dev->list_mutex);
194c30c9b15SDavid Fries mutex_unlock(&dev->mutex);
195c30c9b15SDavid Fries atomic_dec(&dev->refcnt);
196c30c9b15SDavid Fries
1971da177e4SLinus Torvalds while (atomic_read(&dev->refcnt)) {
198674a396cSEvgeniy Polyakov dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n",
1991da177e4SLinus Torvalds dev->name, atomic_read(&dev->refcnt));
2001da177e4SLinus Torvalds
2011da177e4SLinus Torvalds if (msleep_interruptible(1000))
2021da177e4SLinus Torvalds flush_signals(current);
203a0f10464SAlexey Khoroshilov mutex_lock(&dev->list_mutex);
2049fcbbac5SDavid Fries w1_process_callbacks(dev);
205a0f10464SAlexey Khoroshilov mutex_unlock(&dev->list_mutex);
2061da177e4SLinus Torvalds }
207a0f10464SAlexey Khoroshilov mutex_lock(&dev->list_mutex);
2089fcbbac5SDavid Fries w1_process_callbacks(dev);
209a0f10464SAlexey Khoroshilov mutex_unlock(&dev->list_mutex);
2101da177e4SLinus Torvalds
21112003375SEvgeniy Polyakov memset(&msg, 0, sizeof(msg));
2121da177e4SLinus Torvalds msg.id.mst.id = dev->id;
2131da177e4SLinus Torvalds msg.type = W1_MASTER_REMOVE;
2141da177e4SLinus Torvalds w1_netlink_send(dev, &msg);
2151da177e4SLinus Torvalds
2161da177e4SLinus Torvalds w1_free_dev(dev);
2171da177e4SLinus Torvalds }
2181da177e4SLinus Torvalds
219b3be177aSDavid Fries /**
220b3be177aSDavid Fries * w1_remove_master_device() - unregister a master device
221b3be177aSDavid Fries * @bm: master bus device to remove
222b3be177aSDavid Fries */
w1_remove_master_device(struct w1_bus_master * bm)2231da177e4SLinus Torvalds void w1_remove_master_device(struct w1_bus_master *bm)
2241da177e4SLinus Torvalds {
22559d9445eSEvgeniy Polyakov struct w1_master *dev, *found = NULL;
2261da177e4SLinus Torvalds
2277785925dSEvgeniy Polyakov list_for_each_entry(dev, &w1_masters, w1_master_entry) {
2281da177e4SLinus Torvalds if (!dev->initialized)
2291da177e4SLinus Torvalds continue;
2301da177e4SLinus Torvalds
23159d9445eSEvgeniy Polyakov if (dev->bus_master->data == bm->data) {
23259d9445eSEvgeniy Polyakov found = dev;
2331da177e4SLinus Torvalds break;
2341da177e4SLinus Torvalds }
23559d9445eSEvgeniy Polyakov }
2361da177e4SLinus Torvalds
23759d9445eSEvgeniy Polyakov if (!found) {
238fdc9167aSFjodor Schelichow pr_err("Device doesn't exist.\n");
2391da177e4SLinus Torvalds return;
2401da177e4SLinus Torvalds }
2411da177e4SLinus Torvalds
24259d9445eSEvgeniy Polyakov __w1_remove_master_device(found);
2431da177e4SLinus Torvalds }
2441da177e4SLinus Torvalds EXPORT_SYMBOL(w1_remove_master_device);
245