- 根目录:
- drivers
- pps
- pps.c
/*
* PPS core file
*
*
* Copyright (C) 2005-2009 Rodolfo Giometti <giometti@linux.it>
*
* 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 <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 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. 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");