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git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/blob - drivers/w1/w1_int.c
2 * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
15 #include <linux/kernel.h>
16 #include <linux/list.h>
17 #include <linux/delay.h>
18 #include <linux/kthread.h>
19 #include <linux/slab.h>
20 #include <linux/sched/signal.h>
21 #include <linux/export.h>
22 #include <linux/moduleparam.h>
24 #include "w1_internal.h"
25 #include "w1_netlink.h"
27 static int w1_search_count
= -1; /* Default is continual scan */
28 module_param_named(search_count
, w1_search_count
, int, 0);
30 static int w1_enable_pullup
= 1;
31 module_param_named(enable_pullup
, w1_enable_pullup
, int, 0);
33 static struct w1_master
*w1_alloc_dev(u32 id
, int slave_count
, int slave_ttl
,
34 struct device_driver
*driver
,
35 struct device
*device
)
37 struct w1_master
*dev
;
41 * We are in process context(kernel thread), so can sleep.
43 dev
= kzalloc(sizeof(struct w1_master
) + sizeof(struct w1_bus_master
), GFP_KERNEL
);
45 pr_err("Failed to allocate %zd bytes for new w1 device.\n",
46 sizeof(struct w1_master
));
51 dev
->bus_master
= (struct w1_bus_master
*)(dev
+ 1);
53 dev
->owner
= THIS_MODULE
;
54 dev
->max_slave_count
= slave_count
;
59 dev
->slave_ttl
= slave_ttl
;
60 dev
->search_count
= w1_search_count
;
61 dev
->enable_pullup
= w1_enable_pullup
;
63 /* 1 for w1_process to decrement
64 * 1 for __w1_remove_master_device to decrement
66 atomic_set(&dev
->refcnt
, 2);
68 INIT_LIST_HEAD(&dev
->slist
);
69 INIT_LIST_HEAD(&dev
->async_list
);
70 mutex_init(&dev
->mutex
);
71 mutex_init(&dev
->bus_mutex
);
72 mutex_init(&dev
->list_mutex
);
74 memcpy(&dev
->dev
, device
, sizeof(struct device
));
75 dev_set_name(&dev
->dev
, "w1_bus_master%u", dev
->id
);
76 snprintf(dev
->name
, sizeof(dev
->name
), "w1_bus_master%u", dev
->id
);
77 dev
->dev
.init_name
= dev
->name
;
83 err
= device_register(&dev
->dev
);
85 pr_err("Failed to register master device. err=%d\n", err
);
86 put_device(&dev
->dev
);
93 static void w1_free_dev(struct w1_master
*dev
)
95 device_unregister(&dev
->dev
);
99 * w1_add_master_device() - registers a new master device
100 * @master: master bus device to register
102 int w1_add_master_device(struct w1_bus_master
*master
)
104 struct w1_master
*dev
, *entry
;
106 struct w1_netlink_msg msg
;
109 /* validate minimum functionality */
110 if (!(master
->touch_bit
&& master
->reset_bus
) &&
111 !(master
->write_bit
&& master
->read_bit
) &&
112 !(master
->write_byte
&& master
->read_byte
&& master
->reset_bus
)) {
113 pr_err("w1_add_master_device: invalid function set\n");
117 /* Lock until the device is added (or not) to w1_masters. */
118 mutex_lock(&w1_mlock
);
119 /* Search for the first available id (starting at 1). */
124 list_for_each_entry(entry
, &w1_masters
, w1_master_entry
) {
125 if (entry
->id
== id
) {
132 dev
= w1_alloc_dev(id
, w1_max_slave_count
, w1_max_slave_ttl
,
133 &w1_master_driver
, &w1_master_device
);
135 mutex_unlock(&w1_mlock
);
139 retval
= w1_create_master_attributes(dev
);
141 mutex_unlock(&w1_mlock
);
142 goto err_out_free_dev
;
145 memcpy(dev
->bus_master
, master
, sizeof(struct w1_bus_master
));
147 dev
->initialized
= 1;
149 dev
->thread
= kthread_run(&w1_process
, dev
, "%s", dev
->name
);
150 if (IS_ERR(dev
->thread
)) {
151 retval
= PTR_ERR(dev
->thread
);
153 "Failed to create new kernel thread. err=%d\n",
155 mutex_unlock(&w1_mlock
);
156 goto err_out_rm_attr
;
159 list_add(&dev
->w1_master_entry
, &w1_masters
);
160 mutex_unlock(&w1_mlock
);
162 memset(&msg
, 0, sizeof(msg
));
163 msg
.id
.mst
.id
= dev
->id
;
164 msg
.type
= W1_MASTER_ADD
;
165 w1_netlink_send(dev
, &msg
);
169 #if 0 /* Thread cleanup code, not required currently. */
171 set_bit(W1_ABORT_SEARCH
, &dev
->flags
);
172 kthread_stop(dev
->thread
);
175 w1_destroy_master_attributes(dev
);
181 EXPORT_SYMBOL(w1_add_master_device
);
183 void __w1_remove_master_device(struct w1_master
*dev
)
185 struct w1_netlink_msg msg
;
186 struct w1_slave
*sl
, *sln
;
188 mutex_lock(&w1_mlock
);
189 list_del(&dev
->w1_master_entry
);
190 mutex_unlock(&w1_mlock
);
192 set_bit(W1_ABORT_SEARCH
, &dev
->flags
);
193 kthread_stop(dev
->thread
);
195 mutex_lock(&dev
->mutex
);
196 mutex_lock(&dev
->list_mutex
);
197 list_for_each_entry_safe(sl
, sln
, &dev
->slist
, w1_slave_entry
) {
198 mutex_unlock(&dev
->list_mutex
);
200 mutex_lock(&dev
->list_mutex
);
202 w1_destroy_master_attributes(dev
);
203 mutex_unlock(&dev
->list_mutex
);
204 mutex_unlock(&dev
->mutex
);
205 atomic_dec(&dev
->refcnt
);
207 while (atomic_read(&dev
->refcnt
)) {
208 dev_info(&dev
->dev
, "Waiting for %s to become free: refcnt=%d.\n",
209 dev
->name
, atomic_read(&dev
->refcnt
));
211 if (msleep_interruptible(1000))
212 flush_signals(current
);
213 mutex_lock(&dev
->list_mutex
);
214 w1_process_callbacks(dev
);
215 mutex_unlock(&dev
->list_mutex
);
217 mutex_lock(&dev
->list_mutex
);
218 w1_process_callbacks(dev
);
219 mutex_unlock(&dev
->list_mutex
);
221 memset(&msg
, 0, sizeof(msg
));
222 msg
.id
.mst
.id
= dev
->id
;
223 msg
.type
= W1_MASTER_REMOVE
;
224 w1_netlink_send(dev
, &msg
);
230 * w1_remove_master_device() - unregister a master device
231 * @bm: master bus device to remove
233 void w1_remove_master_device(struct w1_bus_master
*bm
)
235 struct w1_master
*dev
, *found
= NULL
;
237 list_for_each_entry(dev
, &w1_masters
, w1_master_entry
) {
238 if (!dev
->initialized
)
241 if (dev
->bus_master
->data
== bm
->data
) {
248 pr_err("Device doesn't exist.\n");
252 __w1_remove_master_device(found
);
254 EXPORT_SYMBOL(w1_remove_master_device
);