LinuxPPS: core support
[pandora-kernel.git] / drivers / pps / pps.c
diff --git a/drivers/pps/pps.c b/drivers/pps/pps.c
new file mode 100644 (file)
index 0000000..ac8cc8c
--- /dev/null
@@ -0,0 +1,312 @@
+/*
+ * 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.
+ */
+
+
+#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/cdev.h>
+#include <linux/poll.h>
+#include <linux/pps_kernel.h>
+
+/*
+ * Local variables
+ */
+
+static dev_t pps_devt;
+static struct class *pps_class;
+
+/*
+ * 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;
+       struct pps_fdata fdata;
+       unsigned long ticks;
+       void __user *uarg = (void __user *) arg;
+       int __user *iuarg = (int __user *) arg;
+       int err;
+
+       switch (cmd) {
+       case PPS_GETPARAMS:
+               pr_debug("PPS_GETPARAMS: source %d\n", pps->id);
+
+               /* Return current parameters */
+               err = copy_to_user(uarg, &pps->params,
+                                               sizeof(struct pps_kparams));
+               if (err)
+                       return -EFAULT;
+
+               break;
+
+       case PPS_SETPARAMS:
+               pr_debug("PPS_SETPARAMS: source %d\n", pps->id);
+
+               /* 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))) {
+                       pr_debug("capture mode unspecified (%x)\n",
+                                                               params.mode);
+                       return -EINVAL;
+               }
+
+               /* Check for supported capabilities */
+               if ((params.mode & ~pps->info.mode) != 0) {
+                       pr_debug("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 */
+                       pr_debug("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:
+               pr_debug("PPS_GETCAP: source %d\n", pps->id);
+
+               err = put_user(pps->info.mode, iuarg);
+               if (err)
+                       return -EFAULT;
+
+               break;
+
+       case PPS_FETCH:
+               pr_debug("PPS_FETCH: source %d\n", pps->id);
+
+               err = copy_from_user(&fdata, uarg, sizeof(struct pps_fdata));
+               if (err)
+                       return -EFAULT;
+
+               pps->go = 0;
+
+               /* Manage the timeout */
+               if (fdata.timeout.flags & PPS_TIME_INVALID)
+                       err = wait_event_interruptible(pps->queue, pps->go);
+               else {
+                       pr_debug("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, pps->go, ticks);
+                               if (err == 0)
+                                       return -ETIMEDOUT;
+                       }
+               }
+
+               /* Check for pending signals */
+               if (err == -ERESTARTSYS) {
+                       pr_debug("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;
+
+       default:
+               return -ENOTTY;
+               break;
+       }
+
+       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);
+       int found;
+
+       found = pps_get_source(pps->id) != 0;
+       if (!found)
+               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;
+
+       /* Free the PPS source and wake up (possible) deregistration */
+       pps_put_source(pps);
+
+       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,
+};
+
+int pps_register_cdev(struct pps_device *pps)
+{
+       int err;
+
+       pps->devno = MKDEV(MAJOR(pps_devt), pps->id);
+       cdev_init(&pps->cdev, &pps_cdev_fops);
+       pps->cdev.owner = pps->info.owner;
+
+       err = cdev_add(&pps->cdev, pps->devno, 1);
+       if (err) {
+               printk(KERN_ERR "pps: %s: failed to add char device %d:%d\n",
+                               pps->info.name, MAJOR(pps_devt), pps->id);
+               return err;
+       }
+       pps->dev = device_create(pps_class, pps->info.dev, pps->devno, NULL,
+                                                       "pps%d", pps->id);
+       if (err)
+               goto del_cdev;
+       dev_set_drvdata(pps->dev, pps);
+
+       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);
+
+       return err;
+}
+
+void pps_unregister_cdev(struct pps_device *pps)
+{
+       device_destroy(pps_class, pps->devno);
+       cdev_del(&pps->cdev);
+}
+
+/*
+ * 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 (!pps_class) {
+               printk(KERN_ERR "pps: failed to allocate class\n");
+               return -ENOMEM;
+       }
+       pps_class->dev_attrs = pps_attrs;
+
+       err = alloc_chrdev_region(&pps_devt, 0, PPS_MAX_SOURCES, "pps");
+       if (err < 0) {
+               printk(KERN_ERR "pps: 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");