drivers/w1/w1_int.c - kernel/msm - Git at Google

 /*
  *	w1_int.c
  *
  * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
  *
  *
  * 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.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  */

 #include <linux/kernel.h>
 #include <linux/list.h>
 #include <linux/delay.h>
 #include <linux/kthread.h>
 #include <linux/slab.h>
 #include <linux/export.h>
 #include <linux/moduleparam.h>

 #include "w1.h"
 #include "w1_log.h"
 #include "w1_netlink.h"
 #include "w1_int.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;
 }

 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_add_master_device);
 EXPORT_SYMBOL(w1_remove_master_device);
	/*
	* w1_int.c
	*
	* Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
	*
	*
	* 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.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	*/

	#include <linux/kernel.h>
	#include <linux/list.h>
	#include <linux/delay.h>
	#include <linux/kthread.h>
	#include <linux/slab.h>
	#include <linux/export.h>
	#include <linux/moduleparam.h>

	#include "w1.h"
	#include "w1_log.h"
	#include "w1_netlink.h"
	#include "w1_int.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;
	}

	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_add_master_device);
	EXPORT_SYMBOL(w1_remove_master_device);