diff options
Diffstat (limited to 'kernel/drivers/w1/w1.c')
| -rw-r--r-- | kernel/drivers/w1/w1.c | 1223 |
1 files changed, 1223 insertions, 0 deletions
diff --git a/kernel/drivers/w1/w1.c b/kernel/drivers/w1/w1.c new file mode 100644 index 000000000..181f41cb9 --- /dev/null +++ b/kernel/drivers/w1/w1.c @@ -0,0 +1,1223 @@ +/* + * w1.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/delay.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/list.h> +#include <linux/interrupt.h> +#include <linux/spinlock.h> +#include <linux/timer.h> +#include <linux/device.h> +#include <linux/slab.h> +#include <linux/sched.h> +#include <linux/kthread.h> +#include <linux/freezer.h> + +#include <linux/atomic.h> + +#include "w1.h" +#include "w1_log.h" +#include "w1_int.h" +#include "w1_family.h" +#include "w1_netlink.h" + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>"); +MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol."); + +static int w1_timeout = 10; +int w1_max_slave_count = 64; +int w1_max_slave_ttl = 10; + +module_param_named(timeout, w1_timeout, int, 0); +MODULE_PARM_DESC(timeout, "time in seconds between automatic slave searches"); +/* A search stops when w1_max_slave_count devices have been found in that + * search. The next search will start over and detect the same set of devices + * on a static 1-wire bus. Memory is not allocated based on this number, just + * on the number of devices known to the kernel. Having a high number does not + * consume additional resources. As a special case, if there is only one + * device on the network and w1_max_slave_count is set to 1, the device id can + * be read directly skipping the normal slower search process. + */ +module_param_named(max_slave_count, w1_max_slave_count, int, 0); +MODULE_PARM_DESC(max_slave_count, + "maximum number of slaves detected in a search"); +module_param_named(slave_ttl, w1_max_slave_ttl, int, 0); +MODULE_PARM_DESC(slave_ttl, + "Number of searches not seeing a slave before it will be removed"); + +DEFINE_MUTEX(w1_mlock); +LIST_HEAD(w1_masters); + +static int w1_master_match(struct device *dev, struct device_driver *drv) +{ + return 1; +} + +static int w1_master_probe(struct device *dev) +{ + return -ENODEV; +} + +static void w1_master_release(struct device *dev) +{ + struct w1_master *md = dev_to_w1_master(dev); + + dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name); + memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master)); + kfree(md); +} + +static void w1_slave_release(struct device *dev) +{ + struct w1_slave *sl = dev_to_w1_slave(dev); + + dev_dbg(dev, "%s: Releasing %s [%p]\n", __func__, sl->name, sl); + + w1_family_put(sl->family); + sl->master->slave_count--; +} + +static ssize_t name_show(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct w1_slave *sl = dev_to_w1_slave(dev); + + return sprintf(buf, "%s\n", sl->name); +} +static DEVICE_ATTR_RO(name); + +static ssize_t id_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct w1_slave *sl = dev_to_w1_slave(dev); + ssize_t count = sizeof(sl->reg_num); + + memcpy(buf, (u8 *)&sl->reg_num, count); + return count; +} +static DEVICE_ATTR_RO(id); + +static struct attribute *w1_slave_attrs[] = { + &dev_attr_name.attr, + &dev_attr_id.attr, + NULL, +}; +ATTRIBUTE_GROUPS(w1_slave); + +/* Default family */ + +static ssize_t rw_write(struct file *filp, struct kobject *kobj, + struct bin_attribute *bin_attr, char *buf, loff_t off, + size_t count) +{ + struct w1_slave *sl = kobj_to_w1_slave(kobj); + + mutex_lock(&sl->master->mutex); + if (w1_reset_select_slave(sl)) { + count = 0; + goto out_up; + } + + w1_write_block(sl->master, buf, count); + +out_up: + mutex_unlock(&sl->master->mutex); + return count; +} + +static ssize_t rw_read(struct file *filp, struct kobject *kobj, + struct bin_attribute *bin_attr, char *buf, loff_t off, + size_t count) +{ + struct w1_slave *sl = kobj_to_w1_slave(kobj); + + mutex_lock(&sl->master->mutex); + w1_read_block(sl->master, buf, count); + mutex_unlock(&sl->master->mutex); + return count; +} + +static BIN_ATTR_RW(rw, PAGE_SIZE); + +static struct bin_attribute *w1_slave_bin_attrs[] = { + &bin_attr_rw, + NULL, +}; + +static const struct attribute_group w1_slave_default_group = { + .bin_attrs = w1_slave_bin_attrs, +}; + +static const struct attribute_group *w1_slave_default_groups[] = { + &w1_slave_default_group, + NULL, +}; + +static struct w1_family_ops w1_default_fops = { + .groups = w1_slave_default_groups, +}; + +static struct w1_family w1_default_family = { + .fops = &w1_default_fops, +}; + +static int w1_uevent(struct device *dev, struct kobj_uevent_env *env); + +static struct bus_type w1_bus_type = { + .name = "w1", + .match = w1_master_match, + .uevent = w1_uevent, +}; + +struct device_driver w1_master_driver = { + .name = "w1_master_driver", + .bus = &w1_bus_type, + .probe = w1_master_probe, +}; + +struct device w1_master_device = { + .parent = NULL, + .bus = &w1_bus_type, + .init_name = "w1 bus master", + .driver = &w1_master_driver, + .release = &w1_master_release +}; + +static struct device_driver w1_slave_driver = { + .name = "w1_slave_driver", + .bus = &w1_bus_type, +}; + +#if 0 +struct device w1_slave_device = { + .parent = NULL, + .bus = &w1_bus_type, + .init_name = "w1 bus slave", + .driver = &w1_slave_driver, + .release = &w1_slave_release +}; +#endif /* 0 */ + +static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct w1_master *md = dev_to_w1_master(dev); + ssize_t count; + + mutex_lock(&md->mutex); + count = sprintf(buf, "%s\n", md->name); + mutex_unlock(&md->mutex); + + return count; +} + +static ssize_t w1_master_attribute_store_search(struct device * dev, + struct device_attribute *attr, + const char * buf, size_t count) +{ + long tmp; + struct w1_master *md = dev_to_w1_master(dev); + int ret; + + ret = kstrtol(buf, 0, &tmp); + if (ret) + return ret; + + mutex_lock(&md->mutex); + md->search_count = tmp; + mutex_unlock(&md->mutex); + /* Only wake if it is going to be searching. */ + if (tmp) + wake_up_process(md->thread); + + return count; +} + +static ssize_t w1_master_attribute_show_search(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct w1_master *md = dev_to_w1_master(dev); + ssize_t count; + + mutex_lock(&md->mutex); + count = sprintf(buf, "%d\n", md->search_count); + mutex_unlock(&md->mutex); + + return count; +} + +static ssize_t w1_master_attribute_store_pullup(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + long tmp; + struct w1_master *md = dev_to_w1_master(dev); + int ret; + + ret = kstrtol(buf, 0, &tmp); + if (ret) + return ret; + + mutex_lock(&md->mutex); + md->enable_pullup = tmp; + mutex_unlock(&md->mutex); + + return count; +} + +static ssize_t w1_master_attribute_show_pullup(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct w1_master *md = dev_to_w1_master(dev); + ssize_t count; + + mutex_lock(&md->mutex); + count = sprintf(buf, "%d\n", md->enable_pullup); + mutex_unlock(&md->mutex); + + return count; +} + +static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct w1_master *md = dev_to_w1_master(dev); + ssize_t count; + + mutex_lock(&md->mutex); + count = sprintf(buf, "0x%p\n", md->bus_master); + mutex_unlock(&md->mutex); + return count; +} + +static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf) +{ + ssize_t count; + count = sprintf(buf, "%d\n", w1_timeout); + return count; +} + +static ssize_t w1_master_attribute_store_max_slave_count(struct device *dev, + struct device_attribute *attr, const char *buf, size_t count) +{ + int tmp; + struct w1_master *md = dev_to_w1_master(dev); + + if (kstrtoint(buf, 0, &tmp) == -EINVAL || tmp < 1) + return -EINVAL; + + mutex_lock(&md->mutex); + md->max_slave_count = tmp; + /* allow each time the max_slave_count is updated */ + clear_bit(W1_WARN_MAX_COUNT, &md->flags); + mutex_unlock(&md->mutex); + + return count; +} + +static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct w1_master *md = dev_to_w1_master(dev); + ssize_t count; + + mutex_lock(&md->mutex); + count = sprintf(buf, "%d\n", md->max_slave_count); + mutex_unlock(&md->mutex); + return count; +} + +static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct w1_master *md = dev_to_w1_master(dev); + ssize_t count; + + mutex_lock(&md->mutex); + count = sprintf(buf, "%lu\n", md->attempts); + mutex_unlock(&md->mutex); + return count; +} + +static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct w1_master *md = dev_to_w1_master(dev); + ssize_t count; + + mutex_lock(&md->mutex); + count = sprintf(buf, "%d\n", md->slave_count); + mutex_unlock(&md->mutex); + return count; +} + +static ssize_t w1_master_attribute_show_slaves(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct w1_master *md = dev_to_w1_master(dev); + int c = PAGE_SIZE; + struct list_head *ent, *n; + struct w1_slave *sl = NULL; + + mutex_lock(&md->list_mutex); + + list_for_each_safe(ent, n, &md->slist) { + sl = list_entry(ent, struct w1_slave, w1_slave_entry); + + c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name); + } + if (!sl) + c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n"); + + mutex_unlock(&md->list_mutex); + + return PAGE_SIZE - c; +} + +static ssize_t w1_master_attribute_show_add(struct device *dev, + struct device_attribute *attr, char *buf) +{ + int c = PAGE_SIZE; + c -= snprintf(buf+PAGE_SIZE - c, c, + "write device id xx-xxxxxxxxxxxx to add slave\n"); + return PAGE_SIZE - c; +} + +static int w1_atoreg_num(struct device *dev, const char *buf, size_t count, + struct w1_reg_num *rn) +{ + unsigned int family; + unsigned long long id; + int i; + u64 rn64_le; + + /* The CRC value isn't read from the user because the sysfs directory + * doesn't include it and most messages from the bus search don't + * print it either. It would be unreasonable for the user to then + * provide it. + */ + const char *error_msg = "bad slave string format, expecting " + "ff-dddddddddddd\n"; + + if (buf[2] != '-') { + dev_err(dev, "%s", error_msg); + return -EINVAL; + } + i = sscanf(buf, "%02x-%012llx", &family, &id); + if (i != 2) { + dev_err(dev, "%s", error_msg); + return -EINVAL; + } + rn->family = family; + rn->id = id; + + rn64_le = cpu_to_le64(*(u64 *)rn); + rn->crc = w1_calc_crc8((u8 *)&rn64_le, 7); + +#if 0 + dev_info(dev, "With CRC device is %02x.%012llx.%02x.\n", + rn->family, (unsigned long long)rn->id, rn->crc); +#endif + + return 0; +} + +/* Searches the slaves in the w1_master and returns a pointer or NULL. + * Note: must not hold list_mutex + */ +struct w1_slave *w1_slave_search_device(struct w1_master *dev, + struct w1_reg_num *rn) +{ + struct w1_slave *sl; + mutex_lock(&dev->list_mutex); + list_for_each_entry(sl, &dev->slist, w1_slave_entry) { + if (sl->reg_num.family == rn->family && + sl->reg_num.id == rn->id && + sl->reg_num.crc == rn->crc) { + mutex_unlock(&dev->list_mutex); + return sl; + } + } + mutex_unlock(&dev->list_mutex); + return NULL; +} + +static ssize_t w1_master_attribute_store_add(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct w1_master *md = dev_to_w1_master(dev); + struct w1_reg_num rn; + struct w1_slave *sl; + ssize_t result = count; + + if (w1_atoreg_num(dev, buf, count, &rn)) + return -EINVAL; + + mutex_lock(&md->mutex); + sl = w1_slave_search_device(md, &rn); + /* It would be nice to do a targeted search one the one-wire bus + * for the new device to see if it is out there or not. But the + * current search doesn't support that. + */ + if (sl) { + dev_info(dev, "Device %s already exists\n", sl->name); + result = -EINVAL; + } else { + w1_attach_slave_device(md, &rn); + } + mutex_unlock(&md->mutex); + + return result; +} + +static ssize_t w1_master_attribute_show_remove(struct device *dev, + struct device_attribute *attr, char *buf) +{ + int c = PAGE_SIZE; + c -= snprintf(buf+PAGE_SIZE - c, c, + "write device id xx-xxxxxxxxxxxx to remove slave\n"); + return PAGE_SIZE - c; +} + +static ssize_t w1_master_attribute_store_remove(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct w1_master *md = dev_to_w1_master(dev); + struct w1_reg_num rn; + struct w1_slave *sl; + ssize_t result = count; + + if (w1_atoreg_num(dev, buf, count, &rn)) + return -EINVAL; + + mutex_lock(&md->mutex); + sl = w1_slave_search_device(md, &rn); + if (sl) { + result = w1_slave_detach(sl); + /* refcnt 0 means it was detached in the call */ + if (result == 0) + result = count; + } else { + dev_info(dev, "Device %02x-%012llx doesn't exists\n", rn.family, + (unsigned long long)rn.id); + result = -EINVAL; + } + mutex_unlock(&md->mutex); + + return result; +} + +#define W1_MASTER_ATTR_RO(_name, _mode) \ + struct device_attribute w1_master_attribute_##_name = \ + __ATTR(w1_master_##_name, _mode, \ + w1_master_attribute_show_##_name, NULL) + +#define W1_MASTER_ATTR_RW(_name, _mode) \ + struct device_attribute w1_master_attribute_##_name = \ + __ATTR(w1_master_##_name, _mode, \ + w1_master_attribute_show_##_name, \ + w1_master_attribute_store_##_name) + +static W1_MASTER_ATTR_RO(name, S_IRUGO); +static W1_MASTER_ATTR_RO(slaves, S_IRUGO); +static W1_MASTER_ATTR_RO(slave_count, S_IRUGO); +static W1_MASTER_ATTR_RW(max_slave_count, S_IRUGO | S_IWUSR | S_IWGRP); +static W1_MASTER_ATTR_RO(attempts, S_IRUGO); +static W1_MASTER_ATTR_RO(timeout, S_IRUGO); +static W1_MASTER_ATTR_RO(pointer, S_IRUGO); +static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUSR | S_IWGRP); +static W1_MASTER_ATTR_RW(pullup, S_IRUGO | S_IWUSR | S_IWGRP); +static W1_MASTER_ATTR_RW(add, S_IRUGO | S_IWUSR | S_IWGRP); +static W1_MASTER_ATTR_RW(remove, S_IRUGO | S_IWUSR | S_IWGRP); + +static struct attribute *w1_master_default_attrs[] = { + &w1_master_attribute_name.attr, + &w1_master_attribute_slaves.attr, + &w1_master_attribute_slave_count.attr, + &w1_master_attribute_max_slave_count.attr, + &w1_master_attribute_attempts.attr, + &w1_master_attribute_timeout.attr, + &w1_master_attribute_pointer.attr, + &w1_master_attribute_search.attr, + &w1_master_attribute_pullup.attr, + &w1_master_attribute_add.attr, + &w1_master_attribute_remove.attr, + NULL +}; + +static struct attribute_group w1_master_defattr_group = { + .attrs = w1_master_default_attrs, +}; + +int w1_create_master_attributes(struct w1_master *master) +{ + return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group); +} + +void w1_destroy_master_attributes(struct w1_master *master) +{ + sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group); +} + +static int w1_uevent(struct device *dev, struct kobj_uevent_env *env) +{ + struct w1_master *md = NULL; + struct w1_slave *sl = NULL; + char *event_owner, *name; + int err = 0; + + if (dev->driver == &w1_master_driver) { + md = container_of(dev, struct w1_master, dev); + event_owner = "master"; + name = md->name; + } else if (dev->driver == &w1_slave_driver) { + sl = container_of(dev, struct w1_slave, dev); + event_owner = "slave"; + name = sl->name; + } else { + dev_dbg(dev, "Unknown event.\n"); + return -EINVAL; + } + + dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n", + event_owner, name, dev_name(dev)); + + if (dev->driver != &w1_slave_driver || !sl) + goto end; + + err = add_uevent_var(env, "W1_FID=%02X", sl->reg_num.family); + if (err) + goto end; + + err = add_uevent_var(env, "W1_SLAVE_ID=%024LX", + (unsigned long long)sl->reg_num.id); +end: + return err; +} + +static int w1_family_notify(unsigned long action, struct w1_slave *sl) +{ + struct w1_family_ops *fops; + int err; + + fops = sl->family->fops; + + if (!fops) + return 0; + + switch (action) { + case BUS_NOTIFY_ADD_DEVICE: + /* if the family driver needs to initialize something... */ + if (fops->add_slave) { + err = fops->add_slave(sl); + if (err < 0) { + dev_err(&sl->dev, + "add_slave() call failed. err=%d\n", + err); + return err; + } + } + if (fops->groups) { + err = sysfs_create_groups(&sl->dev.kobj, fops->groups); + if (err) { + dev_err(&sl->dev, + "sysfs group creation failed. err=%d\n", + err); + return err; + } + } + + break; + case BUS_NOTIFY_DEL_DEVICE: + if (fops->remove_slave) + sl->family->fops->remove_slave(sl); + if (fops->groups) + sysfs_remove_groups(&sl->dev.kobj, fops->groups); + break; + } + return 0; +} + +static int __w1_attach_slave_device(struct w1_slave *sl) +{ + int err; + + sl->dev.parent = &sl->master->dev; + sl->dev.driver = &w1_slave_driver; + sl->dev.bus = &w1_bus_type; + sl->dev.release = &w1_slave_release; + sl->dev.groups = w1_slave_groups; + + dev_set_name(&sl->dev, "%02x-%012llx", + (unsigned int) sl->reg_num.family, + (unsigned long long) sl->reg_num.id); + snprintf(&sl->name[0], sizeof(sl->name), + "%02x-%012llx", + (unsigned int) sl->reg_num.family, + (unsigned long long) sl->reg_num.id); + + dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__, + dev_name(&sl->dev), sl); + + /* suppress for w1_family_notify before sending KOBJ_ADD */ + dev_set_uevent_suppress(&sl->dev, true); + + err = device_register(&sl->dev); + if (err < 0) { + dev_err(&sl->dev, + "Device registration [%s] failed. err=%d\n", + dev_name(&sl->dev), err); + return err; + } + w1_family_notify(BUS_NOTIFY_ADD_DEVICE, sl); + + dev_set_uevent_suppress(&sl->dev, false); + kobject_uevent(&sl->dev.kobj, KOBJ_ADD); + + mutex_lock(&sl->master->list_mutex); + list_add_tail(&sl->w1_slave_entry, &sl->master->slist); + mutex_unlock(&sl->master->list_mutex); + + return 0; +} + +int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn) +{ + struct w1_slave *sl; + struct w1_family *f; + int err; + struct w1_netlink_msg msg; + + sl = kzalloc(sizeof(struct w1_slave), GFP_KERNEL); + if (!sl) { + dev_err(&dev->dev, + "%s: failed to allocate new slave device.\n", + __func__); + return -ENOMEM; + } + + + sl->owner = THIS_MODULE; + sl->master = dev; + set_bit(W1_SLAVE_ACTIVE, &sl->flags); + + memset(&msg, 0, sizeof(msg)); + memcpy(&sl->reg_num, rn, sizeof(sl->reg_num)); + atomic_set(&sl->refcnt, 1); + atomic_inc(&sl->master->refcnt); + + /* slave modules need to be loaded in a context with unlocked mutex */ + mutex_unlock(&dev->mutex); + request_module("w1-family-0x%02x", rn->family); + mutex_lock(&dev->mutex); + + spin_lock(&w1_flock); + f = w1_family_registered(rn->family); + if (!f) { + f= &w1_default_family; + dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n", + rn->family, rn->family, + (unsigned long long)rn->id, rn->crc); + } + __w1_family_get(f); + spin_unlock(&w1_flock); + + sl->family = f; + + + err = __w1_attach_slave_device(sl); + if (err < 0) { + dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__, + sl->name); + w1_family_put(sl->family); + kfree(sl); + return err; + } + + sl->ttl = dev->slave_ttl; + dev->slave_count++; + + memcpy(msg.id.id, rn, sizeof(msg.id)); + msg.type = W1_SLAVE_ADD; + w1_netlink_send(dev, &msg); + + return 0; +} + +int w1_unref_slave(struct w1_slave *sl) +{ + struct w1_master *dev = sl->master; + int refcnt; + mutex_lock(&dev->list_mutex); + refcnt = atomic_sub_return(1, &sl->refcnt); + if (refcnt == 0) { + struct w1_netlink_msg msg; + + dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, + sl->name, sl); + + list_del(&sl->w1_slave_entry); + + memset(&msg, 0, sizeof(msg)); + memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id)); + msg.type = W1_SLAVE_REMOVE; + w1_netlink_send(sl->master, &msg); + + w1_family_notify(BUS_NOTIFY_DEL_DEVICE, sl); + device_unregister(&sl->dev); + #ifdef DEBUG + memset(sl, 0, sizeof(*sl)); + #endif + kfree(sl); + } + atomic_dec(&dev->refcnt); + mutex_unlock(&dev->list_mutex); + return refcnt; +} + +int w1_slave_detach(struct w1_slave *sl) +{ + /* Only detach a slave once as it decreases the refcnt each time. */ + int destroy_now; + mutex_lock(&sl->master->list_mutex); + destroy_now = !test_bit(W1_SLAVE_DETACH, &sl->flags); + set_bit(W1_SLAVE_DETACH, &sl->flags); + mutex_unlock(&sl->master->list_mutex); + + if (destroy_now) + destroy_now = !w1_unref_slave(sl); + return destroy_now ? 0 : -EBUSY; +} + +struct w1_master *w1_search_master_id(u32 id) +{ + struct w1_master *dev; + int found = 0; + + mutex_lock(&w1_mlock); + list_for_each_entry(dev, &w1_masters, w1_master_entry) { + if (dev->id == id) { + found = 1; + atomic_inc(&dev->refcnt); + break; + } + } + mutex_unlock(&w1_mlock); + + return (found)?dev:NULL; +} + +struct w1_slave *w1_search_slave(struct w1_reg_num *id) +{ + struct w1_master *dev; + struct w1_slave *sl = NULL; + int found = 0; + + mutex_lock(&w1_mlock); + list_for_each_entry(dev, &w1_masters, w1_master_entry) { + mutex_lock(&dev->list_mutex); + list_for_each_entry(sl, &dev->slist, w1_slave_entry) { + if (sl->reg_num.family == id->family && + sl->reg_num.id == id->id && + sl->reg_num.crc == id->crc) { + found = 1; + atomic_inc(&dev->refcnt); + atomic_inc(&sl->refcnt); + break; + } + } + mutex_unlock(&dev->list_mutex); + + if (found) + break; + } + mutex_unlock(&w1_mlock); + + return (found)?sl:NULL; +} + +void w1_reconnect_slaves(struct w1_family *f, int attach) +{ + struct w1_slave *sl, *sln; + struct w1_master *dev; + + mutex_lock(&w1_mlock); + list_for_each_entry(dev, &w1_masters, w1_master_entry) { + dev_dbg(&dev->dev, "Reconnecting slaves in device %s " + "for family %02x.\n", dev->name, f->fid); + mutex_lock(&dev->mutex); + mutex_lock(&dev->list_mutex); + list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) { + /* If it is a new family, slaves with the default + * family driver and are that family will be + * connected. If the family is going away, devices + * matching that family are reconneced. + */ + if ((attach && sl->family->fid == W1_FAMILY_DEFAULT + && sl->reg_num.family == f->fid) || + (!attach && sl->family->fid == f->fid)) { + struct w1_reg_num rn; + + mutex_unlock(&dev->list_mutex); + memcpy(&rn, &sl->reg_num, sizeof(rn)); + /* If it was already in use let the automatic + * scan pick it up again later. + */ + if (!w1_slave_detach(sl)) + w1_attach_slave_device(dev, &rn); + mutex_lock(&dev->list_mutex); + } + } + dev_dbg(&dev->dev, "Reconnecting slaves in device %s " + "has been finished.\n", dev->name); + mutex_unlock(&dev->list_mutex); + mutex_unlock(&dev->mutex); + } + mutex_unlock(&w1_mlock); +} + +void w1_slave_found(struct w1_master *dev, u64 rn) +{ + struct w1_slave *sl; + struct w1_reg_num *tmp; + u64 rn_le = cpu_to_le64(rn); + + atomic_inc(&dev->refcnt); + + tmp = (struct w1_reg_num *) &rn; + + sl = w1_slave_search_device(dev, tmp); + if (sl) { + set_bit(W1_SLAVE_ACTIVE, &sl->flags); + } else { + if (rn && tmp->crc == w1_calc_crc8((u8 *)&rn_le, 7)) + w1_attach_slave_device(dev, tmp); + } + + atomic_dec(&dev->refcnt); +} + +/** + * w1_search() - Performs a ROM Search & registers any devices found. + * @dev: The master device to search + * @search_type: W1_SEARCH to search all devices, or W1_ALARM_SEARCH + * to return only devices in the alarmed state + * @cb: Function to call when a device is found + * + * The 1-wire search is a simple binary tree search. + * For each bit of the address, we read two bits and write one bit. + * The bit written will put to sleep all devies that don't match that bit. + * When the two reads differ, the direction choice is obvious. + * When both bits are 0, we must choose a path to take. + * When we can scan all 64 bits without having to choose a path, we are done. + * + * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com + * + */ +void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb) +{ + u64 last_rn, rn, tmp64; + int i, slave_count = 0; + int last_zero, last_device; + int search_bit, desc_bit; + u8 triplet_ret = 0; + + search_bit = 0; + rn = dev->search_id; + last_rn = 0; + last_device = 0; + last_zero = -1; + + desc_bit = 64; + + while ( !last_device && (slave_count++ < dev->max_slave_count) ) { + last_rn = rn; + rn = 0; + + /* + * Reset bus and all 1-wire device state machines + * so they can respond to our requests. + * + * Return 0 - device(s) present, 1 - no devices present. + */ + mutex_lock(&dev->bus_mutex); + if (w1_reset_bus(dev)) { + mutex_unlock(&dev->bus_mutex); + dev_dbg(&dev->dev, "No devices present on the wire.\n"); + break; + } + + /* Do fast search on single slave bus */ + if (dev->max_slave_count == 1) { + int rv; + w1_write_8(dev, W1_READ_ROM); + rv = w1_read_block(dev, (u8 *)&rn, 8); + mutex_unlock(&dev->bus_mutex); + + if (rv == 8 && rn) + cb(dev, rn); + + break; + } + + /* Start the search */ + w1_write_8(dev, search_type); + for (i = 0; i < 64; ++i) { + /* Determine the direction/search bit */ + if (i == desc_bit) + search_bit = 1; /* took the 0 path last time, so take the 1 path */ + else if (i > desc_bit) + search_bit = 0; /* take the 0 path on the next branch */ + else + search_bit = ((last_rn >> i) & 0x1); + + /* Read two bits and write one bit */ + triplet_ret = w1_triplet(dev, search_bit); + + /* quit if no device responded */ + if ( (triplet_ret & 0x03) == 0x03 ) + break; + + /* If both directions were valid, and we took the 0 path... */ + if (triplet_ret == 0) + last_zero = i; + + /* extract the direction taken & update the device number */ + tmp64 = (triplet_ret >> 2); + rn |= (tmp64 << i); + + if (test_bit(W1_ABORT_SEARCH, &dev->flags)) { + mutex_unlock(&dev->bus_mutex); + dev_dbg(&dev->dev, "Abort w1_search\n"); + return; + } + } + mutex_unlock(&dev->bus_mutex); + + if ( (triplet_ret & 0x03) != 0x03 ) { + if ((desc_bit == last_zero) || (last_zero < 0)) { + last_device = 1; + dev->search_id = 0; + } else { + dev->search_id = rn; + } + desc_bit = last_zero; + cb(dev, rn); + } + + if (!last_device && slave_count == dev->max_slave_count && + !test_bit(W1_WARN_MAX_COUNT, &dev->flags)) { + /* Only max_slave_count will be scanned in a search, + * but it will start where it left off next search + * until all ids are identified and then it will start + * over. A continued search will report the previous + * last id as the first id (provided it is still on the + * bus). + */ + dev_info(&dev->dev, "%s: max_slave_count %d reached, " + "will continue next search.\n", __func__, + dev->max_slave_count); + set_bit(W1_WARN_MAX_COUNT, &dev->flags); + } + } +} + +void w1_search_process_cb(struct w1_master *dev, u8 search_type, + w1_slave_found_callback cb) +{ + struct w1_slave *sl, *sln; + + mutex_lock(&dev->list_mutex); + list_for_each_entry(sl, &dev->slist, w1_slave_entry) + clear_bit(W1_SLAVE_ACTIVE, &sl->flags); + mutex_unlock(&dev->list_mutex); + + w1_search_devices(dev, search_type, cb); + + mutex_lock(&dev->list_mutex); + list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) { + if (!test_bit(W1_SLAVE_ACTIVE, &sl->flags) && !--sl->ttl) { + mutex_unlock(&dev->list_mutex); + w1_slave_detach(sl); + mutex_lock(&dev->list_mutex); + } + else if (test_bit(W1_SLAVE_ACTIVE, &sl->flags)) + sl->ttl = dev->slave_ttl; + } + mutex_unlock(&dev->list_mutex); + + if (dev->search_count > 0) + dev->search_count--; +} + +static void w1_search_process(struct w1_master *dev, u8 search_type) +{ + w1_search_process_cb(dev, search_type, w1_slave_found); +} + +/** + * w1_process_callbacks() - execute each dev->async_list callback entry + * @dev: w1_master device + * + * The w1 master list_mutex must be held. + * + * Return: 1 if there were commands to executed 0 otherwise + */ +int w1_process_callbacks(struct w1_master *dev) +{ + int ret = 0; + struct w1_async_cmd *async_cmd, *async_n; + + /* The list can be added to in another thread, loop until it is empty */ + while (!list_empty(&dev->async_list)) { + list_for_each_entry_safe(async_cmd, async_n, &dev->async_list, + async_entry) { + /* drop the lock, if it is a search it can take a long + * time */ + mutex_unlock(&dev->list_mutex); + async_cmd->cb(dev, async_cmd); + ret = 1; + mutex_lock(&dev->list_mutex); + } + } + return ret; +} + +int w1_process(void *data) +{ + struct w1_master *dev = (struct w1_master *) data; + /* As long as w1_timeout is only set by a module parameter the sleep + * time can be calculated in jiffies once. + */ + const unsigned long jtime = msecs_to_jiffies(w1_timeout * 1000); + /* remainder if it woke up early */ + unsigned long jremain = 0; + + for (;;) { + + if (!jremain && dev->search_count) { + mutex_lock(&dev->mutex); + w1_search_process(dev, W1_SEARCH); + mutex_unlock(&dev->mutex); + } + + mutex_lock(&dev->list_mutex); + /* Note, w1_process_callback drops the lock while processing, + * but locks it again before returning. + */ + if (!w1_process_callbacks(dev) && jremain) { + /* a wake up is either to stop the thread, process + * callbacks, or search, it isn't process callbacks, so + * schedule a search. + */ + jremain = 1; + } + + try_to_freeze(); + __set_current_state(TASK_INTERRUPTIBLE); + + /* hold list_mutex until after interruptible to prevent loosing + * the wakeup signal when async_cmd is added. + */ + mutex_unlock(&dev->list_mutex); + + if (kthread_should_stop()) + break; + + /* Only sleep when the search is active. */ + if (dev->search_count) { + if (!jremain) + jremain = jtime; + jremain = schedule_timeout(jremain); + } + else + schedule(); + } + + atomic_dec(&dev->refcnt); + + return 0; +} + +static int __init w1_init(void) +{ + int retval; + + pr_info("Driver for 1-wire Dallas network protocol.\n"); + + w1_init_netlink(); + + retval = bus_register(&w1_bus_type); + if (retval) { + pr_err("Failed to register bus. err=%d.\n", retval); + goto err_out_exit_init; + } + + retval = driver_register(&w1_master_driver); + if (retval) { + pr_err("Failed to register master driver. err=%d.\n", + retval); + goto err_out_bus_unregister; + } + + retval = driver_register(&w1_slave_driver); + if (retval) { + pr_err("Failed to register slave driver. err=%d.\n", + retval); + goto err_out_master_unregister; + } + + return 0; + +#if 0 +/* For undoing the slave register if there was a step after it. */ +err_out_slave_unregister: + driver_unregister(&w1_slave_driver); +#endif + +err_out_master_unregister: + driver_unregister(&w1_master_driver); + +err_out_bus_unregister: + bus_unregister(&w1_bus_type); + +err_out_exit_init: + return retval; +} + +static void __exit w1_fini(void) +{ + struct w1_master *dev; + + /* Set netlink removal messages and some cleanup */ + list_for_each_entry(dev, &w1_masters, w1_master_entry) + __w1_remove_master_device(dev); + + w1_fini_netlink(); + + driver_unregister(&w1_slave_driver); + driver_unregister(&w1_master_driver); + bus_unregister(&w1_bus_type); +} + +module_init(w1_init); +module_exit(w1_fini); |