linux/drivers/pps/pps.c
Thomas Gleixner 74ba9207e1 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 61
Based on 1 normalized pattern(s):

  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

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 441 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520071858.739733335@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-24 17:36:45 +02:00

482 lines
11 KiB
C

// 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 dev_t pps_devt;
static struct class *pps_class;
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);
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;
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 */
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;
}
#ifdef CONFIG_COMPAT
static 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 */
spin_lock_irq(&pps->lock);
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 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,
.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);
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. 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;
}
goto out_unlock;
}
pps->id = err;
mutex_unlock(&pps_idr_lock);
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)) {
err = PTR_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);
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);
}
/*
* 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_groups = pps_groups;
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 "
"<giometti@linux.it>\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 <giometti@linux.it>");
MODULE_DESCRIPTION("LinuxPPS support (RFC 2783) - ver. " PPS_VERSION);
MODULE_LICENSE("GPL");