/* * PPS core file * * * Copyright (C) 2005-2009 Rodolfo Giometti * * 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., 675 Mass Ave, Cambridge, MA 02139, USA. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include #include #include #include #include #include #include "kc.h" /* * Local variables */ static dev_t pps_devt; static struct class *pps_class; static DEFINE_MUTEX(pps_idr_lock); static DEFINE_IDR(pps_idr); /* * Char device methods */ static unsigned int pps_cdev_poll(struct file *file, poll_table *wait) { struct pps_device *pps = file->private_data; poll_wait(file, &pps->queue, wait); return POLLIN | POLLRDNORM; } static int pps_cdev_fasync(int fd, struct file *file, int on) { struct pps_device *pps = file->private_data; return fasync_helper(fd, file, on, &pps->async_queue); } static long pps_cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { struct pps_device *pps = file->private_data; struct pps_kparams params; void __user *uarg = (void __user *) arg; int __user *iuarg = (int __user *) arg; int err; switch (cmd) { case PPS_GETPARAMS: dev_dbg(pps->dev, "PPS_GETPARAMS\n"); spin_lock_irq(&pps->lock); /* Get the current parameters */ params = pps->params; spin_unlock_irq(&pps->lock); err = copy_to_user(uarg, ¶ms, sizeof(struct pps_kparams)); if (err) return -EFAULT; break; case PPS_SETPARAMS: dev_dbg(pps->dev, "PPS_SETPARAMS\n"); /* Check the capabilities */ if (!capable(CAP_SYS_TIME)) return -EPERM; err = copy_from_user(¶ms, uarg, sizeof(struct pps_kparams)); if (err) return -EFAULT; if (!(params.mode & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR))) { dev_dbg(pps->dev, "capture mode unspecified (%x)\n", params.mode); return -EINVAL; } /* Check for supported capabilities */ if ((params.mode & ~pps->info.mode) != 0) { dev_dbg(pps->dev, "unsupported capabilities (%x)\n", params.mode); return -EINVAL; } spin_lock_irq(&pps->lock); /* Save the new parameters */ pps->params = params; /* Restore the read only parameters */ if ((params.mode & (PPS_TSFMT_TSPEC | PPS_TSFMT_NTPFP)) == 0) { /* section 3.3 of RFC 2783 interpreted */ dev_dbg(pps->dev, "time format unspecified (%x)\n", params.mode); pps->params.mode |= PPS_TSFMT_TSPEC; } if (pps->info.mode & PPS_CANWAIT) pps->params.mode |= PPS_CANWAIT; pps->params.api_version = PPS_API_VERS; spin_unlock_irq(&pps->lock); break; case PPS_GETCAP: dev_dbg(pps->dev, "PPS_GETCAP\n"); err = put_user(pps->info.mode, iuarg); if (err) return -EFAULT; break; case PPS_FETCH: { struct pps_fdata fdata; unsigned int ev; dev_dbg(pps->dev, "PPS_FETCH\n"); err = copy_from_user(&fdata, uarg, sizeof(struct pps_fdata)); if (err) return -EFAULT; ev = pps->last_ev; /* Manage the timeout */ if (fdata.timeout.flags & PPS_TIME_INVALID) err = wait_event_interruptible(pps->queue, ev != pps->last_ev); else { unsigned long ticks; dev_dbg(pps->dev, "timeout %lld.%09d\n", (long long) fdata.timeout.sec, fdata.timeout.nsec); ticks = fdata.timeout.sec * HZ; ticks += fdata.timeout.nsec / (NSEC_PER_SEC / HZ); if (ticks != 0) { err = wait_event_interruptible_timeout( pps->queue, ev != pps->last_ev, ticks); if (err == 0) return -ETIMEDOUT; } } /* Check for pending signals */ if (err == -ERESTARTSYS) { dev_dbg(pps->dev, "pending signal caught\n"); return -EINTR; } /* Return the fetched timestamp */ spin_lock_irq(&pps->lock); fdata.info.assert_sequence = pps->assert_sequence; fdata.info.clear_sequence = pps->clear_sequence; fdata.info.assert_tu = pps->assert_tu; fdata.info.clear_tu = pps->clear_tu; fdata.info.current_mode = pps->current_mode; spin_unlock_irq(&pps->lock); err = copy_to_user(uarg, &fdata, sizeof(struct pps_fdata)); if (err) return -EFAULT; break; } case PPS_KC_BIND: { struct pps_bind_args bind_args; dev_dbg(pps->dev, "PPS_KC_BIND\n"); /* Check the capabilities */ if (!capable(CAP_SYS_TIME)) return -EPERM; if (copy_from_user(&bind_args, uarg, sizeof(struct pps_bind_args))) return -EFAULT; /* Check for supported capabilities */ if ((bind_args.edge & ~pps->info.mode) != 0) { dev_err(pps->dev, "unsupported capabilities (%x)\n", bind_args.edge); return -EINVAL; } /* Validate parameters roughly */ if (bind_args.tsformat != PPS_TSFMT_TSPEC || (bind_args.edge & ~PPS_CAPTUREBOTH) != 0 || bind_args.consumer != PPS_KC_HARDPPS) { dev_err(pps->dev, "invalid kernel consumer bind" " parameters (%x)\n", bind_args.edge); return -EINVAL; } err = pps_kc_bind(pps, &bind_args); if (err < 0) return err; break; } default: return -ENOTTY; } return 0; } static int pps_cdev_open(struct inode *inode, struct file *file) { struct pps_device *pps = container_of(inode->i_cdev, struct pps_device, cdev); file->private_data = pps; kobject_get(&pps->dev->kobj); return 0; } static int pps_cdev_release(struct inode *inode, struct file *file) { struct pps_device *pps = container_of(inode->i_cdev, struct pps_device, cdev); kobject_put(&pps->dev->kobj); return 0; } /* * Char device stuff */ static const struct file_operations pps_cdev_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .poll = pps_cdev_poll, .fasync = pps_cdev_fasync, .unlocked_ioctl = pps_cdev_ioctl, .open = pps_cdev_open, .release = pps_cdev_release, }; static void pps_device_destruct(struct device *dev) { struct pps_device *pps = dev_get_drvdata(dev); cdev_del(&pps->cdev); /* Now we can release the ID for re-use */ pr_debug("deallocating pps%d\n", pps->id); mutex_lock(&pps_idr_lock); idr_remove(&pps_idr, pps->id); mutex_unlock(&pps_idr_lock); kfree(dev); kfree(pps); } int pps_register_cdev(struct pps_device *pps) { int err; dev_t devt; mutex_lock(&pps_idr_lock); /* Get new ID for the new PPS source */ if (idr_pre_get(&pps_idr, GFP_KERNEL) == 0) { mutex_unlock(&pps_idr_lock); return -ENOMEM; } /* Now really allocate the PPS source. * After idr_get_new() calling the new source will be freely available * into the kernel. */ err = idr_get_new(&pps_idr, pps, &pps->id); mutex_unlock(&pps_idr_lock); if (err < 0) return err; pps->id &= MAX_ID_MASK; if (pps->id >= PPS_MAX_SOURCES) { pr_err("%s: too many PPS sources in the system\n", pps->info.name); err = -EBUSY; goto free_idr; } devt = MKDEV(MAJOR(pps_devt), pps->id); cdev_init(&pps->cdev, &pps_cdev_fops); pps->cdev.owner = pps->info.owner; err = cdev_add(&pps->cdev, devt, 1); if (err) { pr_err("%s: failed to add char device %d:%d\n", pps->info.name, MAJOR(pps_devt), pps->id); goto free_idr; } pps->dev = device_create(pps_class, pps->info.dev, devt, pps, "pps%d", pps->id); if (IS_ERR(pps->dev)) goto del_cdev; /* Override the release function with our own */ pps->dev->release = pps_device_destruct; pr_debug("source %s got cdev (%d:%d)\n", pps->info.name, MAJOR(pps_devt), pps->id); return 0; del_cdev: cdev_del(&pps->cdev); free_idr: mutex_lock(&pps_idr_lock); idr_remove(&pps_idr, pps->id); mutex_unlock(&pps_idr_lock); return err; } void pps_unregister_cdev(struct pps_device *pps) { pr_debug("unregistering pps%d\n", pps->id); pps->lookup_cookie = NULL; device_destroy(pps_class, pps->dev->devt); } /* * Look up a pps device by magic cookie. * The cookie is usually a pointer to some enclosing device, but this * code doesn't care; you should never be dereferencing it. * * This is a bit of a kludge that is currently used only by the PPS * serial line discipline. It may need to be tweaked when a second user * is found. * * There is no function interface for setting the lookup_cookie field. * It's initialized to NULL when the pps device is created, and if a * client wants to use it, just fill it in afterward. * * The cookie is automatically set to NULL in pps_unregister_source() * so that it will not be used again, even if the pps device cannot * be removed from the idr due to pending references holding the minor * number in use. */ struct pps_device *pps_lookup_dev(void const *cookie) { struct pps_device *pps; unsigned id; rcu_read_lock(); idr_for_each_entry(&pps_idr, pps, id) if (cookie == pps->lookup_cookie) break; rcu_read_unlock(); return pps; } EXPORT_SYMBOL(pps_lookup_dev); /* * Module stuff */ static void __exit pps_exit(void) { class_destroy(pps_class); unregister_chrdev_region(pps_devt, PPS_MAX_SOURCES); } static int __init pps_init(void) { int err; pps_class = class_create(THIS_MODULE, "pps"); if (IS_ERR(pps_class)) { pr_err("failed to allocate class\n"); return PTR_ERR(pps_class); } pps_class->dev_attrs = pps_attrs; err = alloc_chrdev_region(&pps_devt, 0, PPS_MAX_SOURCES, "pps"); if (err < 0) { pr_err("failed to allocate char device region\n"); goto remove_class; } pr_info("LinuxPPS API ver. %d registered\n", PPS_API_VERS); pr_info("Software ver. %s - Copyright 2005-2007 Rodolfo Giometti " "\n", PPS_VERSION); return 0; remove_class: class_destroy(pps_class); return err; } subsys_initcall(pps_init); module_exit(pps_exit); MODULE_AUTHOR("Rodolfo Giometti "); MODULE_DESCRIPTION("LinuxPPS support (RFC 2783) - ver. " PPS_VERSION); MODULE_LICENSE("GPL");