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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * PPS core file4 *5 * Copyright (C) 2005-2009 Rodolfo Giometti <giometti@linux.it>6 */7 8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt9 10#include <linux/kernel.h>11#include <linux/module.h>12#include <linux/init.h>13#include <linux/sched.h>14#include <linux/uaccess.h>15#include <linux/idr.h>16#include <linux/mutex.h>17#include <linux/cdev.h>18#include <linux/poll.h>19#include <linux/pps_kernel.h>20#include <linux/slab.h>21 22#include "kc.h"23 24/*25 * Local variables26 */27 28static dev_t pps_devt;29static struct class *pps_class;30 31static DEFINE_MUTEX(pps_idr_lock);32static DEFINE_IDR(pps_idr);33 34/*35 * Char device methods36 */37 38static __poll_t pps_cdev_poll(struct file *file, poll_table *wait)39{40 struct pps_device *pps = file->private_data;41 42 poll_wait(file, &pps->queue, wait);43 44 return EPOLLIN | EPOLLRDNORM;45}46 47static int pps_cdev_fasync(int fd, struct file *file, int on)48{49 struct pps_device *pps = file->private_data;50 return fasync_helper(fd, file, on, &pps->async_queue);51}52 53static int pps_cdev_pps_fetch(struct pps_device *pps, struct pps_fdata *fdata)54{55 unsigned int ev = pps->last_ev;56 int err = 0;57 58 /* Manage the timeout */59 if (fdata->timeout.flags & PPS_TIME_INVALID)60 err = wait_event_interruptible(pps->queue,61 ev != pps->last_ev);62 else {63 unsigned long ticks;64 65 dev_dbg(pps->dev, "timeout %lld.%09d\n",66 (long long) fdata->timeout.sec,67 fdata->timeout.nsec);68 ticks = fdata->timeout.sec * HZ;69 ticks += fdata->timeout.nsec / (NSEC_PER_SEC / HZ);70 71 if (ticks != 0) {72 err = wait_event_interruptible_timeout(73 pps->queue,74 ev != pps->last_ev,75 ticks);76 if (err == 0)77 return -ETIMEDOUT;78 }79 }80 81 /* Check for pending signals */82 if (err == -ERESTARTSYS) {83 dev_dbg(pps->dev, "pending signal caught\n");84 return -EINTR;85 }86 87 return 0;88}89 90static long pps_cdev_ioctl(struct file *file,91 unsigned int cmd, unsigned long arg)92{93 struct pps_device *pps = file->private_data;94 struct pps_kparams params;95 void __user *uarg = (void __user *) arg;96 int __user *iuarg = (int __user *) arg;97 int err;98 99 switch (cmd) {100 case PPS_GETPARAMS:101 dev_dbg(pps->dev, "PPS_GETPARAMS\n");102 103 spin_lock_irq(&pps->lock);104 105 /* Get the current parameters */106 params = pps->params;107 108 spin_unlock_irq(&pps->lock);109 110 err = copy_to_user(uarg, ¶ms, sizeof(struct pps_kparams));111 if (err)112 return -EFAULT;113 114 break;115 116 case PPS_SETPARAMS:117 dev_dbg(pps->dev, "PPS_SETPARAMS\n");118 119 /* Check the capabilities */120 if (!capable(CAP_SYS_TIME))121 return -EPERM;122 123 err = copy_from_user(¶ms, uarg, sizeof(struct pps_kparams));124 if (err)125 return -EFAULT;126 if (!(params.mode & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR))) {127 dev_dbg(pps->dev, "capture mode unspecified (%x)\n",128 params.mode);129 return -EINVAL;130 }131 132 /* Check for supported capabilities */133 if ((params.mode & ~pps->info.mode) != 0) {134 dev_dbg(pps->dev, "unsupported capabilities (%x)\n",135 params.mode);136 return -EINVAL;137 }138 139 spin_lock_irq(&pps->lock);140 141 /* Save the new parameters */142 pps->params = params;143 144 /* Restore the read only parameters */145 if ((params.mode & (PPS_TSFMT_TSPEC | PPS_TSFMT_NTPFP)) == 0) {146 /* section 3.3 of RFC 2783 interpreted */147 dev_dbg(pps->dev, "time format unspecified (%x)\n",148 params.mode);149 pps->params.mode |= PPS_TSFMT_TSPEC;150 }151 if (pps->info.mode & PPS_CANWAIT)152 pps->params.mode |= PPS_CANWAIT;153 pps->params.api_version = PPS_API_VERS;154 155 /*156 * Clear unused fields of pps_kparams to avoid leaking157 * uninitialized data of the PPS_SETPARAMS caller via158 * PPS_GETPARAMS159 */160 pps->params.assert_off_tu.flags = 0;161 pps->params.clear_off_tu.flags = 0;162 163 spin_unlock_irq(&pps->lock);164 165 break;166 167 case PPS_GETCAP:168 dev_dbg(pps->dev, "PPS_GETCAP\n");169 170 err = put_user(pps->info.mode, iuarg);171 if (err)172 return -EFAULT;173 174 break;175 176 case PPS_FETCH: {177 struct pps_fdata fdata;178 179 dev_dbg(pps->dev, "PPS_FETCH\n");180 181 err = copy_from_user(&fdata, uarg, sizeof(struct pps_fdata));182 if (err)183 return -EFAULT;184 185 err = pps_cdev_pps_fetch(pps, &fdata);186 if (err)187 return err;188 189 /* Return the fetched timestamp */190 spin_lock_irq(&pps->lock);191 192 fdata.info.assert_sequence = pps->assert_sequence;193 fdata.info.clear_sequence = pps->clear_sequence;194 fdata.info.assert_tu = pps->assert_tu;195 fdata.info.clear_tu = pps->clear_tu;196 fdata.info.current_mode = pps->current_mode;197 198 spin_unlock_irq(&pps->lock);199 200 err = copy_to_user(uarg, &fdata, sizeof(struct pps_fdata));201 if (err)202 return -EFAULT;203 204 break;205 }206 case PPS_KC_BIND: {207 struct pps_bind_args bind_args;208 209 dev_dbg(pps->dev, "PPS_KC_BIND\n");210 211 /* Check the capabilities */212 if (!capable(CAP_SYS_TIME))213 return -EPERM;214 215 if (copy_from_user(&bind_args, uarg,216 sizeof(struct pps_bind_args)))217 return -EFAULT;218 219 /* Check for supported capabilities */220 if ((bind_args.edge & ~pps->info.mode) != 0) {221 dev_err(pps->dev, "unsupported capabilities (%x)\n",222 bind_args.edge);223 return -EINVAL;224 }225 226 /* Validate parameters roughly */227 if (bind_args.tsformat != PPS_TSFMT_TSPEC ||228 (bind_args.edge & ~PPS_CAPTUREBOTH) != 0 ||229 bind_args.consumer != PPS_KC_HARDPPS) {230 dev_err(pps->dev, "invalid kernel consumer bind"231 " parameters (%x)\n", bind_args.edge);232 return -EINVAL;233 }234 235 err = pps_kc_bind(pps, &bind_args);236 if (err < 0)237 return err;238 239 break;240 }241 default:242 return -ENOTTY;243 }244 245 return 0;246}247 248#ifdef CONFIG_COMPAT249static long pps_cdev_compat_ioctl(struct file *file,250 unsigned int cmd, unsigned long arg)251{252 struct pps_device *pps = file->private_data;253 void __user *uarg = (void __user *) arg;254 255 cmd = _IOC(_IOC_DIR(cmd), _IOC_TYPE(cmd), _IOC_NR(cmd), sizeof(void *));256 257 if (cmd == PPS_FETCH) {258 struct pps_fdata_compat compat;259 struct pps_fdata fdata;260 int err;261 262 dev_dbg(pps->dev, "PPS_FETCH\n");263 264 err = copy_from_user(&compat, uarg, sizeof(struct pps_fdata_compat));265 if (err)266 return -EFAULT;267 268 memcpy(&fdata.timeout, &compat.timeout,269 sizeof(struct pps_ktime_compat));270 271 err = pps_cdev_pps_fetch(pps, &fdata);272 if (err)273 return err;274 275 /* Return the fetched timestamp */276 spin_lock_irq(&pps->lock);277 278 compat.info.assert_sequence = pps->assert_sequence;279 compat.info.clear_sequence = pps->clear_sequence;280 compat.info.current_mode = pps->current_mode;281 282 memcpy(&compat.info.assert_tu, &pps->assert_tu,283 sizeof(struct pps_ktime_compat));284 memcpy(&compat.info.clear_tu, &pps->clear_tu,285 sizeof(struct pps_ktime_compat));286 287 spin_unlock_irq(&pps->lock);288 289 return copy_to_user(uarg, &compat,290 sizeof(struct pps_fdata_compat)) ? -EFAULT : 0;291 }292 293 return pps_cdev_ioctl(file, cmd, arg);294}295#else296#define pps_cdev_compat_ioctl NULL297#endif298 299static int pps_cdev_open(struct inode *inode, struct file *file)300{301 struct pps_device *pps = container_of(inode->i_cdev,302 struct pps_device, cdev);303 file->private_data = pps;304 kobject_get(&pps->dev->kobj);305 return 0;306}307 308static int pps_cdev_release(struct inode *inode, struct file *file)309{310 struct pps_device *pps = container_of(inode->i_cdev,311 struct pps_device, cdev);312 kobject_put(&pps->dev->kobj);313 return 0;314}315 316/*317 * Char device stuff318 */319 320static const struct file_operations pps_cdev_fops = {321 .owner = THIS_MODULE,322 .poll = pps_cdev_poll,323 .fasync = pps_cdev_fasync,324 .compat_ioctl = pps_cdev_compat_ioctl,325 .unlocked_ioctl = pps_cdev_ioctl,326 .open = pps_cdev_open,327 .release = pps_cdev_release,328};329 330static void pps_device_destruct(struct device *dev)331{332 struct pps_device *pps = dev_get_drvdata(dev);333 334 cdev_del(&pps->cdev);335 336 /* Now we can release the ID for re-use */337 pr_debug("deallocating pps%d\n", pps->id);338 mutex_lock(&pps_idr_lock);339 idr_remove(&pps_idr, pps->id);340 mutex_unlock(&pps_idr_lock);341 342 kfree(dev);343 kfree(pps);344}345 346int pps_register_cdev(struct pps_device *pps)347{348 int err;349 dev_t devt;350 351 mutex_lock(&pps_idr_lock);352 /*353 * Get new ID for the new PPS source. After idr_alloc() calling354 * the new source will be freely available into the kernel.355 */356 err = idr_alloc(&pps_idr, pps, 0, PPS_MAX_SOURCES, GFP_KERNEL);357 if (err < 0) {358 if (err == -ENOSPC) {359 pr_err("%s: too many PPS sources in the system\n",360 pps->info.name);361 err = -EBUSY;362 }363 goto out_unlock;364 }365 pps->id = err;366 mutex_unlock(&pps_idr_lock);367 368 devt = MKDEV(MAJOR(pps_devt), pps->id);369 370 cdev_init(&pps->cdev, &pps_cdev_fops);371 pps->cdev.owner = pps->info.owner;372 373 err = cdev_add(&pps->cdev, devt, 1);374 if (err) {375 pr_err("%s: failed to add char device %d:%d\n",376 pps->info.name, MAJOR(pps_devt), pps->id);377 goto free_idr;378 }379 pps->dev = device_create(pps_class, pps->info.dev, devt, pps,380 "pps%d", pps->id);381 if (IS_ERR(pps->dev)) {382 err = PTR_ERR(pps->dev);383 goto del_cdev;384 }385 386 /* Override the release function with our own */387 pps->dev->release = pps_device_destruct;388 389 pr_debug("source %s got cdev (%d:%d)\n", pps->info.name,390 MAJOR(pps_devt), pps->id);391 392 return 0;393 394del_cdev:395 cdev_del(&pps->cdev);396 397free_idr:398 mutex_lock(&pps_idr_lock);399 idr_remove(&pps_idr, pps->id);400out_unlock:401 mutex_unlock(&pps_idr_lock);402 return err;403}404 405void pps_unregister_cdev(struct pps_device *pps)406{407 pr_debug("unregistering pps%d\n", pps->id);408 pps->lookup_cookie = NULL;409 device_destroy(pps_class, pps->dev->devt);410}411 412/*413 * Look up a pps device by magic cookie.414 * The cookie is usually a pointer to some enclosing device, but this415 * code doesn't care; you should never be dereferencing it.416 *417 * This is a bit of a kludge that is currently used only by the PPS418 * serial line discipline. It may need to be tweaked when a second user419 * is found.420 *421 * There is no function interface for setting the lookup_cookie field.422 * It's initialized to NULL when the pps device is created, and if a423 * client wants to use it, just fill it in afterward.424 *425 * The cookie is automatically set to NULL in pps_unregister_source()426 * so that it will not be used again, even if the pps device cannot427 * be removed from the idr due to pending references holding the minor428 * number in use.429 */430struct pps_device *pps_lookup_dev(void const *cookie)431{432 struct pps_device *pps;433 unsigned id;434 435 rcu_read_lock();436 idr_for_each_entry(&pps_idr, pps, id)437 if (cookie == pps->lookup_cookie)438 break;439 rcu_read_unlock();440 return pps;441}442EXPORT_SYMBOL(pps_lookup_dev);443 444/*445 * Module stuff446 */447 448static void __exit pps_exit(void)449{450 class_destroy(pps_class);451 unregister_chrdev_region(pps_devt, PPS_MAX_SOURCES);452}453 454static int __init pps_init(void)455{456 int err;457 458 pps_class = class_create("pps");459 if (IS_ERR(pps_class)) {460 pr_err("failed to allocate class\n");461 return PTR_ERR(pps_class);462 }463 pps_class->dev_groups = pps_groups;464 465 err = alloc_chrdev_region(&pps_devt, 0, PPS_MAX_SOURCES, "pps");466 if (err < 0) {467 pr_err("failed to allocate char device region\n");468 goto remove_class;469 }470 471 pr_info("LinuxPPS API ver. %d registered\n", PPS_API_VERS);472 pr_info("Software ver. %s - Copyright 2005-2007 Rodolfo Giometti "473 "<giometti@linux.it>\n", PPS_VERSION);474 475 return 0;476 477remove_class:478 class_destroy(pps_class);479 480 return err;481}482 483subsys_initcall(pps_init);484module_exit(pps_exit);485 486MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");487MODULE_DESCRIPTION("LinuxPPS support (RFC 2783) - ver. " PPS_VERSION);488MODULE_LICENSE("GPL");489