/* * w1.c * * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru> * * * 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 <asm/atomic.h> #include "w1.h" #include "w1_io.h" #include "w1_log.h" #include "w1_int.h" #include "w1_family.h" #include "w1_netlink.h" MODULE_LICENSE("GPL"); MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>"); MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol."); static int w1_timeout = 10; int w1_max_slave_count = 10; int w1_max_slave_ttl = 10; module_param_named(timeout, w1_timeout, int, 0); module_param_named(max_slave_count, w1_max_slave_count, int, 0); module_param_named(slave_ttl, w1_max_slave_ttl, int, 0); DEFINE_SPINLOCK(w1_mlock); LIST_HEAD(w1_masters); static pid_t control_thread; static int control_needs_exit; static DECLARE_COMPLETION(w1_control_complete); /* stuff for the default family */ static ssize_t w1_famdefault_read_name(struct device *dev, struct device_attribute *attr, char *buf) { struct w1_slave *sl = container_of(dev, struct w1_slave, dev); return(sprintf(buf, "%s\n", sl->name)); } static struct w1_family_ops w1_default_fops = { .rname = &w1_famdefault_read_name, }; static struct w1_family w1_default_family = { .fops = &w1_default_fops, }; 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 int w1_master_remove(struct device *dev) { return 0; } static void w1_master_release(struct device *dev) { struct w1_master *md = container_of(dev, struct w1_master, dev); complete(&md->dev_released); } static void w1_slave_release(struct device *dev) { struct w1_slave *sl = container_of(dev, struct w1_slave, dev); complete(&sl->dev_released); } static ssize_t w1_default_read_name(struct device *dev, struct device_attribute *attr, char *buf) { return sprintf(buf, "No family registered.\n"); } static ssize_t w1_default_read_bin(struct kobject *kobj, char *buf, loff_t off, size_t count) { return sprintf(buf, "No family registered.\n"); } static struct device_attribute w1_slave_attribute = __ATTR(name, S_IRUGO, w1_default_read_name, NULL); static struct bin_attribute w1_slave_bin_attribute = { .attr = { .name = "w1_slave", .mode = S_IRUGO, .owner = THIS_MODULE, }, .size = W1_SLAVE_DATA_SIZE, .read = &w1_default_read_bin, }; static struct bus_type w1_bus_type = { .name = "w1", .match = w1_master_match, }; struct device_driver w1_driver = { .name = "w1_driver", .bus = &w1_bus_type, .probe = w1_master_probe, .remove = w1_master_remove, }; struct device w1_device = { .parent = NULL, .bus = &w1_bus_type, .bus_id = "w1 bus master", .driver = &w1_driver, .release = &w1_master_release }; static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf) { struct w1_master *md = container_of(dev, struct w1_master, dev); ssize_t count; if (down_interruptible (&md->mutex)) return -EBUSY; count = sprintf(buf, "%s\n", md->name); up(&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) { struct w1_master *md = container_of(dev, struct w1_master, dev); if (down_interruptible (&md->mutex)) return -EBUSY; md->search_count = simple_strtol(buf, NULL, 0); up(&md->mutex); return count; } static ssize_t w1_master_attribute_show_search(struct device *dev, struct device_attribute *attr, char *buf) { struct w1_master *md = container_of(dev, struct w1_master, dev); ssize_t count; if (down_interruptible (&md->mutex)) return -EBUSY; count = sprintf(buf, "%d\n", md->search_count); up(&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 = container_of(dev, struct w1_master, dev); ssize_t count; if (down_interruptible(&md->mutex)) return -EBUSY; count = sprintf(buf, "0x%p\n", md->bus_master); up(&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_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf) { struct w1_master *md = container_of(dev, struct w1_master, dev); ssize_t count; if (down_interruptible(&md->mutex)) return -EBUSY; count = sprintf(buf, "%d\n", md->max_slave_count); up(&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 = container_of(dev, struct w1_master, dev); ssize_t count; if (down_interruptible(&md->mutex)) return -EBUSY; count = sprintf(buf, "%lu\n", md->attempts); up(&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 = container_of(dev, struct w1_master, dev); ssize_t count; if (down_interruptible(&md->mutex)) return -EBUSY; count = sprintf(buf, "%d\n", md->slave_count); up(&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 = container_of(dev, struct w1_master, dev); int c = PAGE_SIZE; if (down_interruptible(&md->mutex)) return -EBUSY; if (md->slave_count == 0) c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n"); else { struct list_head *ent, *n; struct w1_slave *sl; 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); } } up(&md->mutex); return PAGE_SIZE - c; } #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_RO(max_slave_count, S_IRUGO); 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_IWUGO); 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, 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_attach_slave_device(struct w1_slave *sl) { int err; sl->dev.parent = &sl->master->dev; sl->dev.driver = sl->master->driver; sl->dev.bus = &w1_bus_type; sl->dev.release = &w1_slave_release; snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id), "%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.\n", __func__, &sl->dev.bus_id[0]); err = device_register(&sl->dev); if (err < 0) { dev_err(&sl->dev, "Device registration [%s] failed. err=%d\n", sl->dev.bus_id, err); return err; } memcpy(&sl->attr_bin, &w1_slave_bin_attribute, sizeof(sl->attr_bin)); memcpy(&sl->attr_name, &w1_slave_attribute, sizeof(sl->attr_name)); sl->attr_bin.read = sl->family->fops->rbin; sl->attr_name.show = sl->family->fops->rname; err = device_create_file(&sl->dev, &sl->attr_name); if (err < 0) { dev_err(&sl->dev, "sysfs file creation for [%s] failed. err=%d\n", sl->dev.bus_id, err); device_unregister(&sl->dev); return err; } if ( sl->attr_bin.read ) { err = sysfs_create_bin_file(&sl->dev.kobj, &sl->attr_bin); if (err < 0) { dev_err(&sl->dev, "sysfs file creation for [%s] failed. err=%d\n", sl->dev.bus_id, err); device_remove_file(&sl->dev, &sl->attr_name); device_unregister(&sl->dev); return err; } } list_add_tail(&sl->w1_slave_entry, &sl->master->slist); return 0; } static 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 = kmalloc(sizeof(struct w1_slave), GFP_KERNEL); if (!sl) { dev_err(&dev->dev, "%s: failed to allocate new slave device.\n", __func__); return -ENOMEM; } memset(sl, 0, sizeof(*sl)); sl->owner = THIS_MODULE; sl->master = dev; set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags); memcpy(&sl->reg_num, rn, sizeof(sl->reg_num)); atomic_set(&sl->refcnt, 0); init_completion(&sl->dev_released); 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.id)); msg.type = W1_SLAVE_ADD; w1_netlink_send(dev, &msg); return 0; } static void w1_slave_detach(struct w1_slave *sl) { struct w1_netlink_msg msg; dev_info(&sl->dev, "%s: detaching %s.\n", __func__, sl->name); while (atomic_read(&sl->refcnt)) { printk(KERN_INFO "Waiting for %s to become free: refcnt=%d.\n", sl->name, atomic_read(&sl->refcnt)); if (msleep_interruptible(1000)) flush_signals(current); } if ( sl->attr_bin.read ) { sysfs_remove_bin_file (&sl->dev.kobj, &sl->attr_bin); } device_remove_file(&sl->dev, &sl->attr_name); device_unregister(&sl->dev); w1_family_put(sl->family); sl->master->slave_count--; memcpy(&msg.id.id, &sl->reg_num, sizeof(msg.id.id)); msg.type = W1_SLAVE_REMOVE; w1_netlink_send(sl->master, &msg); } static struct w1_master *w1_search_master(unsigned long data) { struct w1_master *dev; int found = 0; spin_lock_bh(&w1_mlock); list_for_each_entry(dev, &w1_masters, w1_master_entry) { if (dev->bus_master->data == data) { found = 1; atomic_inc(&dev->refcnt); break; } } spin_unlock_bh(&w1_mlock); return (found)?dev:NULL; } void w1_reconnect_slaves(struct w1_family *f) { struct w1_master *dev; spin_lock_bh(&w1_mlock); list_for_each_entry(dev, &w1_masters, w1_master_entry) { dev_info(&dev->dev, "Reconnecting slaves in %s into new family %02x.\n", dev->name, f->fid); set_bit(W1_MASTER_NEED_RECONNECT, &dev->flags); } spin_unlock_bh(&w1_mlock); } static void w1_slave_found(unsigned long data, u64 rn) { int slave_count; struct w1_slave *sl; struct list_head *ent; struct w1_reg_num *tmp; int family_found = 0; struct w1_master *dev; u64 rn_le = cpu_to_le64(rn); dev = w1_search_master(data); if (!dev) { printk(KERN_ERR "Failed to find w1 master device for data %08lx, it is impossible.\n", data); return; } tmp = (struct w1_reg_num *) &rn; slave_count = 0; list_for_each(ent, &dev->slist) { sl = list_entry(ent, struct w1_slave, w1_slave_entry); if (sl->reg_num.family == tmp->family && sl->reg_num.id == tmp->id && sl->reg_num.crc == tmp->crc) { set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags); break; } else if (sl->reg_num.family == tmp->family) { family_found = 1; break; } slave_count++; } if (slave_count == dev->slave_count && rn && ((rn >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn_le, 7)) { w1_attach_slave_device(dev, tmp); } atomic_dec(&dev->refcnt); } /** * Performs a ROM Search & registers any devices 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 * * @dev The master device to search * @cb Function to call when a device is found */ void w1_search(struct w1_master *dev, 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 = 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. */ if (w1_reset_bus(dev)) { dev_dbg(&dev->dev, "No devices present on the wire.\n"); break; } /* Start the search */ w1_write_8(dev, W1_SEARCH); 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 ( (triplet_ret & 0x03) != 0x03 ) { if ( (desc_bit == last_zero) || (last_zero < 0)) last_device = 1; desc_bit = last_zero; cb(dev->bus_master->data, rn); } } } static int w1_control(void *data) { struct w1_slave *sl, *sln; struct w1_master *dev, *n; int err, have_to_wait = 0; daemonize("w1_control"); allow_signal(SIGTERM); while (!control_needs_exit || have_to_wait) { have_to_wait = 0; try_to_freeze(); msleep_interruptible(w1_timeout * 1000); if (signal_pending(current)) flush_signals(current); list_for_each_entry_safe(dev, n, &w1_masters, w1_master_entry) { if (!control_needs_exit && !dev->flags) continue; /* * Little race: we can create thread but not set the flag. * Get a chance for external process to set flag up. */ if (!dev->initialized) { have_to_wait = 1; continue; } if (control_needs_exit) { set_bit(W1_MASTER_NEED_EXIT, &dev->flags); err = kill_proc(dev->kpid, SIGTERM, 1); if (err) dev_err(&dev->dev, "Failed to send signal to w1 kernel thread %d.\n", dev->kpid); } if (test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) { wait_for_completion(&dev->dev_exited); spin_lock_bh(&w1_mlock); list_del(&dev->w1_master_entry); spin_unlock_bh(&w1_mlock); list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) { list_del(&sl->w1_slave_entry); w1_slave_detach(sl); kfree(sl); } w1_destroy_master_attributes(dev); atomic_dec(&dev->refcnt); continue; } if (test_bit(W1_MASTER_NEED_RECONNECT, &dev->flags)) { dev_info(&dev->dev, "Reconnecting slaves in device %s.\n", dev->name); down(&dev->mutex); list_for_each_entry(sl, &dev->slist, w1_slave_entry) { if (sl->family->fid == W1_FAMILY_DEFAULT) { struct w1_reg_num rn; list_del(&sl->w1_slave_entry); w1_slave_detach(sl); memcpy(&rn, &sl->reg_num, sizeof(rn)); kfree(sl); w1_attach_slave_device(dev, &rn); } } clear_bit(W1_MASTER_NEED_RECONNECT, &dev->flags); up(&dev->mutex); } } } complete_and_exit(&w1_control_complete, 0); } int w1_process(void *data) { struct w1_master *dev = (struct w1_master *) data; struct w1_slave *sl, *sln; daemonize("%s", dev->name); allow_signal(SIGTERM); while (!test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) { try_to_freeze(); msleep_interruptible(w1_timeout * 1000); if (signal_pending(current)) flush_signals(current); if (test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) break; if (!dev->initialized) continue; if (dev->search_count == 0) continue; if (down_interruptible(&dev->mutex)) continue; list_for_each_entry(sl, &dev->slist, w1_slave_entry) clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags); w1_search_devices(dev, w1_slave_found); list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) { if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl) { list_del (&sl->w1_slave_entry); w1_slave_detach (sl); kfree (sl); dev->slave_count--; } else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags)) sl->ttl = dev->slave_ttl; } if (dev->search_count > 0) dev->search_count--; up(&dev->mutex); } atomic_dec(&dev->refcnt); complete_and_exit(&dev->dev_exited, 0); return 0; } static int w1_init(void) { int retval; printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n"); retval = bus_register(&w1_bus_type); if (retval) { printk(KERN_ERR "Failed to register bus. err=%d.\n", retval); goto err_out_exit_init; } retval = driver_register(&w1_driver); if (retval) { printk(KERN_ERR "Failed to register master driver. err=%d.\n", retval); goto err_out_bus_unregister; } control_thread = kernel_thread(&w1_control, NULL, 0); if (control_thread < 0) { printk(KERN_ERR "Failed to create control thread. err=%d\n", control_thread); retval = control_thread; goto err_out_driver_unregister; } return 0; err_out_driver_unregister: driver_unregister(&w1_driver); err_out_bus_unregister: bus_unregister(&w1_bus_type); err_out_exit_init: return retval; } static void w1_fini(void) { struct w1_master *dev; list_for_each_entry(dev, &w1_masters, w1_master_entry) __w1_remove_master_device(dev); control_needs_exit = 1; wait_for_completion(&w1_control_complete); driver_unregister(&w1_driver); bus_unregister(&w1_bus_type); } module_init(w1_init); module_exit(w1_fini);