linux/drivers/w1/w1_int.c
Thomas Gleixner c942fddf87 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157
Based on 3 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version this program is distributed in the
  hope that it will be useful but without any warranty without even
  the implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version [author] [kishon] [vijay] [abraham]
  [i] [kishon]@[ti] [com] this program is distributed in the hope that
  it will be useful but without any warranty without even the implied
  warranty of merchantability or fitness for a particular purpose see
  the gnu general public license for more details

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version [author] [graeme] [gregory]
  [gg]@[slimlogic] [co] [uk] [author] [kishon] [vijay] [abraham] [i]
  [kishon]@[ti] [com] [based] [on] [twl6030]_[usb] [c] [author] [hema]
  [hk] [hemahk]@[ti] [com] this program is distributed in the hope
  that it will be useful but without any warranty without even the
  implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1105 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.202006027@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:37 -07:00

246 lines
5.7 KiB
C

// 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);