--- /dev/null
+/*
+ * 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");
Code Review / kvmfornfv.git / blobdiff