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![Otavio Salvador](/assets/img/avatar_default.png)
Signed-off-by: Otavio Salvador <otavio@ossystems.com.br> Acked-by: Evgeniy Polyakov <zbr@ioremap.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
254 lines
6.3 KiB
C
254 lines
6.3 KiB
C
/*
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* w1_int.c
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*
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* Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
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*
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <linux/kernel.h>
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#include <linux/list.h>
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#include <linux/delay.h>
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#include <linux/kthread.h>
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#include <linux/slab.h>
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#include <linux/export.h>
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#include <linux/moduleparam.h>
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#include "w1.h"
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#include "w1_log.h"
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#include "w1_netlink.h"
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#include "w1_int.h"
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static int w1_search_count = -1; /* Default is continual scan */
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module_param_named(search_count, w1_search_count, int, 0);
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static int w1_enable_pullup = 1;
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module_param_named(enable_pullup, w1_enable_pullup, int, 0);
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static struct w1_master * w1_alloc_dev(u32 id, int slave_count, int slave_ttl,
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struct device_driver *driver,
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struct device *device)
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{
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struct w1_master *dev;
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int err;
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/*
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* We are in process context(kernel thread), so can sleep.
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*/
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dev = kzalloc(sizeof(struct w1_master) + sizeof(struct w1_bus_master), GFP_KERNEL);
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if (!dev) {
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printk(KERN_ERR
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"Failed to allocate %zd bytes for new w1 device.\n",
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sizeof(struct w1_master));
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return NULL;
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}
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dev->bus_master = (struct w1_bus_master *)(dev + 1);
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dev->owner = THIS_MODULE;
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dev->max_slave_count = slave_count;
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dev->slave_count = 0;
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dev->attempts = 0;
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dev->initialized = 0;
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dev->id = id;
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dev->slave_ttl = slave_ttl;
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dev->search_count = w1_search_count;
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dev->enable_pullup = w1_enable_pullup;
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/* 1 for w1_process to decrement
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* 1 for __w1_remove_master_device to decrement
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*/
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atomic_set(&dev->refcnt, 2);
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INIT_LIST_HEAD(&dev->slist);
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mutex_init(&dev->mutex);
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mutex_init(&dev->bus_mutex);
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memcpy(&dev->dev, device, sizeof(struct device));
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dev_set_name(&dev->dev, "w1_bus_master%u", dev->id);
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snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id);
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dev->dev.init_name = dev->name;
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dev->driver = driver;
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dev->seq = 1;
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err = device_register(&dev->dev);
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if (err) {
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printk(KERN_ERR "Failed to register master device. err=%d\n", err);
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memset(dev, 0, sizeof(struct w1_master));
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kfree(dev);
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dev = NULL;
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}
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return dev;
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}
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static void w1_free_dev(struct w1_master *dev)
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{
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device_unregister(&dev->dev);
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}
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int w1_add_master_device(struct w1_bus_master *master)
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{
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struct w1_master *dev, *entry;
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int retval = 0;
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struct w1_netlink_msg msg;
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int id, found;
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/* validate minimum functionality */
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if (!(master->touch_bit && master->reset_bus) &&
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!(master->write_bit && master->read_bit) &&
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!(master->write_byte && master->read_byte && master->reset_bus)) {
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printk(KERN_ERR "w1_add_master_device: invalid function set\n");
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return(-EINVAL);
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}
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/* While it would be electrically possible to make a device that
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* generated a strong pullup in bit bang mode, only hardware that
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* controls 1-wire time frames are even expected to support a strong
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* pullup. w1_io.c would need to support calling set_pullup before
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* the last write_bit operation of a w1_write_8 which it currently
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* doesn't.
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*/
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if (!master->write_byte && !master->touch_bit && master->set_pullup) {
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printk(KERN_ERR "w1_add_master_device: set_pullup requires "
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"write_byte or touch_bit, disabling\n");
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master->set_pullup = NULL;
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}
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/* Lock until the device is added (or not) to w1_masters. */
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mutex_lock(&w1_mlock);
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/* Search for the first available id (starting at 1). */
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id = 0;
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do {
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++id;
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found = 0;
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list_for_each_entry(entry, &w1_masters, w1_master_entry) {
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if (entry->id == id) {
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found = 1;
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break;
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}
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}
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} while (found);
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dev = w1_alloc_dev(id, w1_max_slave_count, w1_max_slave_ttl,
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&w1_master_driver, &w1_master_device);
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if (!dev) {
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mutex_unlock(&w1_mlock);
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return -ENOMEM;
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}
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retval = w1_create_master_attributes(dev);
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if (retval) {
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mutex_unlock(&w1_mlock);
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goto err_out_free_dev;
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}
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memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));
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dev->initialized = 1;
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dev->thread = kthread_run(&w1_process, dev, "%s", dev->name);
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if (IS_ERR(dev->thread)) {
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retval = PTR_ERR(dev->thread);
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dev_err(&dev->dev,
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"Failed to create new kernel thread. err=%d\n",
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retval);
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mutex_unlock(&w1_mlock);
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goto err_out_rm_attr;
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}
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list_add(&dev->w1_master_entry, &w1_masters);
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mutex_unlock(&w1_mlock);
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memset(&msg, 0, sizeof(msg));
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msg.id.mst.id = dev->id;
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msg.type = W1_MASTER_ADD;
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w1_netlink_send(dev, &msg);
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return 0;
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#if 0 /* Thread cleanup code, not required currently. */
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err_out_kill_thread:
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kthread_stop(dev->thread);
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#endif
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err_out_rm_attr:
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w1_destroy_master_attributes(dev);
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err_out_free_dev:
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w1_free_dev(dev);
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return retval;
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}
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void __w1_remove_master_device(struct w1_master *dev)
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{
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struct w1_netlink_msg msg;
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struct w1_slave *sl, *sln;
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kthread_stop(dev->thread);
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mutex_lock(&w1_mlock);
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list_del(&dev->w1_master_entry);
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mutex_unlock(&w1_mlock);
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mutex_lock(&dev->mutex);
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list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry)
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w1_slave_detach(sl);
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w1_destroy_master_attributes(dev);
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mutex_unlock(&dev->mutex);
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atomic_dec(&dev->refcnt);
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while (atomic_read(&dev->refcnt)) {
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dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n",
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dev->name, atomic_read(&dev->refcnt));
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if (msleep_interruptible(1000))
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flush_signals(current);
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}
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memset(&msg, 0, sizeof(msg));
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msg.id.mst.id = dev->id;
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msg.type = W1_MASTER_REMOVE;
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w1_netlink_send(dev, &msg);
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w1_free_dev(dev);
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}
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void w1_remove_master_device(struct w1_bus_master *bm)
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{
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struct w1_master *dev, *found = NULL;
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list_for_each_entry(dev, &w1_masters, w1_master_entry) {
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if (!dev->initialized)
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continue;
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if (dev->bus_master->data == bm->data) {
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found = dev;
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break;
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}
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}
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if (!found) {
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printk(KERN_ERR "Device doesn't exist.\n");
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return;
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}
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__w1_remove_master_device(found);
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}
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EXPORT_SYMBOL(w1_add_master_device);
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EXPORT_SYMBOL(w1_remove_master_device);
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