// SPDX-License-Identifier: GPL-2.0-or-later/* * PPS core file * * Copyright (C) 2005-2009   Rodolfo Giometti <giometti@linux.it> */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/kernel.h>#include <linux/module.h>#include <linux/init.h>#include <linux/sched.h>#include <linux/uaccess.h>#include <linux/idr.h>#include <linux/mutex.h>#include <linux/cdev.h>#include <linux/poll.h>#include <linux/pps_kernel.h>#include <linux/slab.h> #include "kc.h" /* * Local variables */ static int pps_major;static const struct class pps_class = {	.name		= "pps",	.dev_groups	= pps_groups}; static DEFINE_MUTEX(pps_idr_lock);static DEFINE_IDR(pps_idr); /* * Char device methods */ static __poll_t pps_cdev_poll(struct file *file, poll_table *wait){	struct pps_device *pps = file->private_data; 	poll_wait(file, &pps->queue, wait); 	if (pps->last_fetched_ev == pps->last_ev)		return 0; 	return EPOLLIN | EPOLLRDNORM;} 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 int pps_cdev_pps_fetch(struct pps_device *pps, struct pps_fdata *fdata){	unsigned int ev = pps->last_ev;	int err = 0; 	/* 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 0;} 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, &params, 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(&params, 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; 		/*		 * Clear unused fields of pps_kparams to avoid leaking		 * uninitialized data of the PPS_SETPARAMS caller via		 * PPS_GETPARAMS		 */		pps->params.assert_off_tu.flags = 0;		pps->params.clear_off_tu.flags = 0; 		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; 		dev_dbg(&pps->dev, "PPS_FETCH\n"); 		err = copy_from_user(&fdata, uarg, sizeof(struct pps_fdata));		if (err)			return -EFAULT; 		err = pps_cdev_pps_fetch(pps, &fdata);		if (err)			return err; 		/* Return the fetched timestamp and save last fetched event  */		spin_lock_irq(&pps->lock); 		pps->last_fetched_ev = pps->last_ev; 		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;} #ifdef CONFIG_COMPATstatic long pps_cdev_compat_ioctl(struct file *file,		unsigned int cmd, unsigned long arg){	struct pps_device *pps = file->private_data;	void __user *uarg = (void __user *) arg; 	cmd = _IOC(_IOC_DIR(cmd), _IOC_TYPE(cmd), _IOC_NR(cmd), sizeof(void *)); 	if (cmd == PPS_FETCH) {		struct pps_fdata_compat compat;		struct pps_fdata fdata;		int err; 		dev_dbg(&pps->dev, "PPS_FETCH\n"); 		err = copy_from_user(&compat, uarg, sizeof(struct pps_fdata_compat));		if (err)			return -EFAULT; 		memcpy(&fdata.timeout, &compat.timeout,					sizeof(struct pps_ktime_compat)); 		err = pps_cdev_pps_fetch(pps, &fdata);		if (err)			return err; 		/* Return the fetched timestamp and save last fetched event  */		spin_lock_irq(&pps->lock); 		pps->last_fetched_ev = pps->last_ev; 		compat.info.assert_sequence = pps->assert_sequence;		compat.info.clear_sequence = pps->clear_sequence;		compat.info.current_mode = pps->current_mode; 		memcpy(&compat.info.assert_tu, &pps->assert_tu,				sizeof(struct pps_ktime_compat));		memcpy(&compat.info.clear_tu, &pps->clear_tu,				sizeof(struct pps_ktime_compat)); 		spin_unlock_irq(&pps->lock); 		return copy_to_user(uarg, &compat,				sizeof(struct pps_fdata_compat)) ? -EFAULT : 0;	} 	return pps_cdev_ioctl(file, cmd, arg);}#else#define pps_cdev_compat_ioctl	NULL#endif static struct pps_device *pps_idr_get(unsigned long id){	struct pps_device *pps; 	mutex_lock(&pps_idr_lock);	pps = idr_find(&pps_idr, id);	if (pps)		get_device(&pps->dev); 	mutex_unlock(&pps_idr_lock);	return pps;} static int pps_cdev_open(struct inode *inode, struct file *file){	struct pps_device *pps = pps_idr_get(iminor(inode)); 	if (!pps)		return -ENODEV; 	file->private_data = pps;	return 0;} static int pps_cdev_release(struct inode *inode, struct file *file){	struct pps_device *pps = file->private_data; 	WARN_ON(pps->id != iminor(inode));	put_device(&pps->dev);	return 0;} /* * Char device stuff */ static const struct file_operations pps_cdev_fops = {	.owner		= THIS_MODULE,	.poll		= pps_cdev_poll,	.fasync		= pps_cdev_fasync,	.compat_ioctl	= pps_cdev_compat_ioctl,	.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); 	pr_debug("deallocating pps%d\n", pps->id);	kfree(pps);} int pps_register_cdev(struct pps_device *pps){	int err; 	mutex_lock(&pps_idr_lock);	/*	 * Get new ID for the new PPS source.  After idr_alloc() calling	 * the new source will be freely available into the kernel.	 */	err = idr_alloc(&pps_idr, pps, 0, PPS_MAX_SOURCES, GFP_KERNEL);	if (err < 0) {		if (err == -ENOSPC) {			pr_err("%s: too many PPS sources in the system\n",			       pps->info.name);			err = -EBUSY;		}		kfree(pps);		goto out_unlock;	}	pps->id = err; 	pps->dev.class = &pps_class;	pps->dev.parent = pps->info.dev;	pps->dev.devt = MKDEV(pps_major, pps->id);	dev_set_drvdata(&pps->dev, pps);	dev_set_name(&pps->dev, "pps%d", pps->id);	pps->dev.release = pps_device_destruct;	err = device_register(&pps->dev);	if (err)		goto free_idr; 	pr_debug("source %s got cdev (%d:%d)\n", pps->info.name, pps_major,		 pps->id); 	get_device(&pps->dev);	mutex_unlock(&pps_idr_lock);	return 0; free_idr:	idr_remove(&pps_idr, pps->id);	put_device(&pps->dev);out_unlock:	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); 	/* Now we can release the ID for re-use */	mutex_lock(&pps_idr_lock);	idr_remove(&pps_idr, pps->id);	put_device(&pps->dev);	mutex_unlock(&pps_idr_lock);} /* * 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. * * Since pps_idr holds a reference to the device, the returned * pps_device is guaranteed to be valid until pps_unregister_cdev() is * called on it. But after calling pps_unregister_cdev(), it may be * freed at any time. */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_unregister(&pps_class);	__unregister_chrdev(pps_major, 0, PPS_MAX_SOURCES, "pps");} static int __init pps_init(void){	int err; 	err = class_register(&pps_class);	if (err) {		pr_err("failed to register class\n");		return err;	} 	pps_major = __register_chrdev(0, 0, PPS_MAX_SOURCES, "pps",				      &pps_cdev_fops);	if (pps_major < 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 "		"<giometti@linux.it>\n", PPS_VERSION); 	return 0; remove_class:	class_unregister(&pps_class);	return pps_major;} subsys_initcall(pps_init);module_exit(pps_exit); 

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