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489 lines
11 KiB
489 lines
11 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* PPS core file |
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* |
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* Copyright (C) 2005-2009 Rodolfo Giometti <[email protected]> |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/init.h> |
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#include <linux/sched.h> |
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#include <linux/uaccess.h> |
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#include <linux/idr.h> |
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#include <linux/mutex.h> |
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#include <linux/cdev.h> |
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#include <linux/poll.h> |
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#include <linux/pps_kernel.h> |
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#include <linux/slab.h> |
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#include "kc.h" |
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/* |
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* Local variables |
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*/ |
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static dev_t pps_devt; |
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static struct class *pps_class; |
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static DEFINE_MUTEX(pps_idr_lock); |
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static DEFINE_IDR(pps_idr); |
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/* |
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* Char device methods |
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*/ |
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static __poll_t pps_cdev_poll(struct file *file, poll_table *wait) |
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{ |
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struct pps_device *pps = file->private_data; |
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poll_wait(file, &pps->queue, wait); |
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return EPOLLIN | EPOLLRDNORM; |
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} |
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static int pps_cdev_fasync(int fd, struct file *file, int on) |
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{ |
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struct pps_device *pps = file->private_data; |
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return fasync_helper(fd, file, on, &pps->async_queue); |
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} |
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static int pps_cdev_pps_fetch(struct pps_device *pps, struct pps_fdata *fdata) |
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{ |
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unsigned int ev = pps->last_ev; |
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int err = 0; |
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/* Manage the timeout */ |
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if (fdata->timeout.flags & PPS_TIME_INVALID) |
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err = wait_event_interruptible(pps->queue, |
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ev != pps->last_ev); |
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else { |
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unsigned long ticks; |
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dev_dbg(pps->dev, "timeout %lld.%09d\n", |
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(long long) fdata->timeout.sec, |
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fdata->timeout.nsec); |
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ticks = fdata->timeout.sec * HZ; |
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ticks += fdata->timeout.nsec / (NSEC_PER_SEC / HZ); |
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if (ticks != 0) { |
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err = wait_event_interruptible_timeout( |
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pps->queue, |
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ev != pps->last_ev, |
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ticks); |
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if (err == 0) |
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return -ETIMEDOUT; |
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} |
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} |
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/* Check for pending signals */ |
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if (err == -ERESTARTSYS) { |
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dev_dbg(pps->dev, "pending signal caught\n"); |
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return -EINTR; |
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} |
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return 0; |
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} |
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static long pps_cdev_ioctl(struct file *file, |
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unsigned int cmd, unsigned long arg) |
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{ |
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struct pps_device *pps = file->private_data; |
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struct pps_kparams params; |
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void __user *uarg = (void __user *) arg; |
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int __user *iuarg = (int __user *) arg; |
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int err; |
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switch (cmd) { |
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case PPS_GETPARAMS: |
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dev_dbg(pps->dev, "PPS_GETPARAMS\n"); |
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spin_lock_irq(&pps->lock); |
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/* Get the current parameters */ |
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params = pps->params; |
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spin_unlock_irq(&pps->lock); |
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err = copy_to_user(uarg, ¶ms, sizeof(struct pps_kparams)); |
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if (err) |
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return -EFAULT; |
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break; |
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case PPS_SETPARAMS: |
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dev_dbg(pps->dev, "PPS_SETPARAMS\n"); |
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/* Check the capabilities */ |
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if (!capable(CAP_SYS_TIME)) |
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return -EPERM; |
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err = copy_from_user(¶ms, uarg, sizeof(struct pps_kparams)); |
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if (err) |
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return -EFAULT; |
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if (!(params.mode & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR))) { |
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dev_dbg(pps->dev, "capture mode unspecified (%x)\n", |
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params.mode); |
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return -EINVAL; |
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} |
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/* Check for supported capabilities */ |
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if ((params.mode & ~pps->info.mode) != 0) { |
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dev_dbg(pps->dev, "unsupported capabilities (%x)\n", |
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params.mode); |
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return -EINVAL; |
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} |
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spin_lock_irq(&pps->lock); |
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/* Save the new parameters */ |
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pps->params = params; |
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/* Restore the read only parameters */ |
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if ((params.mode & (PPS_TSFMT_TSPEC | PPS_TSFMT_NTPFP)) == 0) { |
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/* section 3.3 of RFC 2783 interpreted */ |
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dev_dbg(pps->dev, "time format unspecified (%x)\n", |
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params.mode); |
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pps->params.mode |= PPS_TSFMT_TSPEC; |
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} |
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if (pps->info.mode & PPS_CANWAIT) |
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pps->params.mode |= PPS_CANWAIT; |
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pps->params.api_version = PPS_API_VERS; |
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/* |
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* Clear unused fields of pps_kparams to avoid leaking |
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* uninitialized data of the PPS_SETPARAMS caller via |
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* PPS_GETPARAMS |
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*/ |
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pps->params.assert_off_tu.flags = 0; |
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pps->params.clear_off_tu.flags = 0; |
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spin_unlock_irq(&pps->lock); |
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break; |
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case PPS_GETCAP: |
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dev_dbg(pps->dev, "PPS_GETCAP\n"); |
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err = put_user(pps->info.mode, iuarg); |
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if (err) |
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return -EFAULT; |
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break; |
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case PPS_FETCH: { |
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struct pps_fdata fdata; |
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dev_dbg(pps->dev, "PPS_FETCH\n"); |
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err = copy_from_user(&fdata, uarg, sizeof(struct pps_fdata)); |
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if (err) |
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return -EFAULT; |
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err = pps_cdev_pps_fetch(pps, &fdata); |
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if (err) |
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return err; |
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/* Return the fetched timestamp */ |
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spin_lock_irq(&pps->lock); |
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fdata.info.assert_sequence = pps->assert_sequence; |
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fdata.info.clear_sequence = pps->clear_sequence; |
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fdata.info.assert_tu = pps->assert_tu; |
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fdata.info.clear_tu = pps->clear_tu; |
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fdata.info.current_mode = pps->current_mode; |
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spin_unlock_irq(&pps->lock); |
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err = copy_to_user(uarg, &fdata, sizeof(struct pps_fdata)); |
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if (err) |
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return -EFAULT; |
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break; |
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} |
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case PPS_KC_BIND: { |
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struct pps_bind_args bind_args; |
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dev_dbg(pps->dev, "PPS_KC_BIND\n"); |
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/* Check the capabilities */ |
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if (!capable(CAP_SYS_TIME)) |
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return -EPERM; |
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if (copy_from_user(&bind_args, uarg, |
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sizeof(struct pps_bind_args))) |
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return -EFAULT; |
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/* Check for supported capabilities */ |
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if ((bind_args.edge & ~pps->info.mode) != 0) { |
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dev_err(pps->dev, "unsupported capabilities (%x)\n", |
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bind_args.edge); |
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return -EINVAL; |
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} |
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/* Validate parameters roughly */ |
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if (bind_args.tsformat != PPS_TSFMT_TSPEC || |
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(bind_args.edge & ~PPS_CAPTUREBOTH) != 0 || |
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bind_args.consumer != PPS_KC_HARDPPS) { |
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dev_err(pps->dev, "invalid kernel consumer bind" |
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" parameters (%x)\n", bind_args.edge); |
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return -EINVAL; |
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} |
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err = pps_kc_bind(pps, &bind_args); |
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if (err < 0) |
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return err; |
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break; |
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} |
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default: |
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return -ENOTTY; |
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} |
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return 0; |
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} |
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#ifdef CONFIG_COMPAT |
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static long pps_cdev_compat_ioctl(struct file *file, |
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unsigned int cmd, unsigned long arg) |
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{ |
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struct pps_device *pps = file->private_data; |
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void __user *uarg = (void __user *) arg; |
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cmd = _IOC(_IOC_DIR(cmd), _IOC_TYPE(cmd), _IOC_NR(cmd), sizeof(void *)); |
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if (cmd == PPS_FETCH) { |
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struct pps_fdata_compat compat; |
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struct pps_fdata fdata; |
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int err; |
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dev_dbg(pps->dev, "PPS_FETCH\n"); |
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err = copy_from_user(&compat, uarg, sizeof(struct pps_fdata_compat)); |
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if (err) |
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return -EFAULT; |
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memcpy(&fdata.timeout, &compat.timeout, |
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sizeof(struct pps_ktime_compat)); |
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err = pps_cdev_pps_fetch(pps, &fdata); |
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if (err) |
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return err; |
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/* Return the fetched timestamp */ |
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spin_lock_irq(&pps->lock); |
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compat.info.assert_sequence = pps->assert_sequence; |
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compat.info.clear_sequence = pps->clear_sequence; |
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compat.info.current_mode = pps->current_mode; |
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memcpy(&compat.info.assert_tu, &pps->assert_tu, |
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sizeof(struct pps_ktime_compat)); |
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memcpy(&compat.info.clear_tu, &pps->clear_tu, |
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sizeof(struct pps_ktime_compat)); |
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spin_unlock_irq(&pps->lock); |
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return copy_to_user(uarg, &compat, |
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sizeof(struct pps_fdata_compat)) ? -EFAULT : 0; |
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} |
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return pps_cdev_ioctl(file, cmd, arg); |
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} |
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#else |
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#define pps_cdev_compat_ioctl NULL |
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#endif |
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static int pps_cdev_open(struct inode *inode, struct file *file) |
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{ |
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struct pps_device *pps = container_of(inode->i_cdev, |
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struct pps_device, cdev); |
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file->private_data = pps; |
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kobject_get(&pps->dev->kobj); |
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return 0; |
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} |
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static int pps_cdev_release(struct inode *inode, struct file *file) |
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{ |
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struct pps_device *pps = container_of(inode->i_cdev, |
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struct pps_device, cdev); |
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kobject_put(&pps->dev->kobj); |
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return 0; |
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} |
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/* |
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* Char device stuff |
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*/ |
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static const struct file_operations pps_cdev_fops = { |
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.owner = THIS_MODULE, |
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.llseek = no_llseek, |
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.poll = pps_cdev_poll, |
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.fasync = pps_cdev_fasync, |
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.compat_ioctl = pps_cdev_compat_ioctl, |
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.unlocked_ioctl = pps_cdev_ioctl, |
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.open = pps_cdev_open, |
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.release = pps_cdev_release, |
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}; |
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static void pps_device_destruct(struct device *dev) |
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{ |
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struct pps_device *pps = dev_get_drvdata(dev); |
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cdev_del(&pps->cdev); |
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/* Now we can release the ID for re-use */ |
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pr_debug("deallocating pps%d\n", pps->id); |
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mutex_lock(&pps_idr_lock); |
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idr_remove(&pps_idr, pps->id); |
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mutex_unlock(&pps_idr_lock); |
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kfree(dev); |
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kfree(pps); |
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} |
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int pps_register_cdev(struct pps_device *pps) |
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{ |
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int err; |
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dev_t devt; |
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mutex_lock(&pps_idr_lock); |
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/* |
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* Get new ID for the new PPS source. After idr_alloc() calling |
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* the new source will be freely available into the kernel. |
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*/ |
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err = idr_alloc(&pps_idr, pps, 0, PPS_MAX_SOURCES, GFP_KERNEL); |
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if (err < 0) { |
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if (err == -ENOSPC) { |
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pr_err("%s: too many PPS sources in the system\n", |
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pps->info.name); |
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err = -EBUSY; |
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} |
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goto out_unlock; |
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} |
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pps->id = err; |
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mutex_unlock(&pps_idr_lock); |
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devt = MKDEV(MAJOR(pps_devt), pps->id); |
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cdev_init(&pps->cdev, &pps_cdev_fops); |
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pps->cdev.owner = pps->info.owner; |
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err = cdev_add(&pps->cdev, devt, 1); |
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if (err) { |
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pr_err("%s: failed to add char device %d:%d\n", |
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pps->info.name, MAJOR(pps_devt), pps->id); |
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goto free_idr; |
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} |
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pps->dev = device_create(pps_class, pps->info.dev, devt, pps, |
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"pps%d", pps->id); |
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if (IS_ERR(pps->dev)) { |
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err = PTR_ERR(pps->dev); |
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goto del_cdev; |
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} |
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/* Override the release function with our own */ |
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pps->dev->release = pps_device_destruct; |
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pr_debug("source %s got cdev (%d:%d)\n", pps->info.name, |
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MAJOR(pps_devt), pps->id); |
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return 0; |
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del_cdev: |
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cdev_del(&pps->cdev); |
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free_idr: |
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mutex_lock(&pps_idr_lock); |
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idr_remove(&pps_idr, pps->id); |
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out_unlock: |
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mutex_unlock(&pps_idr_lock); |
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return err; |
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} |
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void pps_unregister_cdev(struct pps_device *pps) |
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{ |
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pr_debug("unregistering pps%d\n", pps->id); |
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pps->lookup_cookie = NULL; |
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device_destroy(pps_class, pps->dev->devt); |
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} |
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/* |
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* Look up a pps device by magic cookie. |
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* The cookie is usually a pointer to some enclosing device, but this |
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* code doesn't care; you should never be dereferencing it. |
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* |
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* This is a bit of a kludge that is currently used only by the PPS |
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* serial line discipline. It may need to be tweaked when a second user |
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* is found. |
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* |
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* There is no function interface for setting the lookup_cookie field. |
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* It's initialized to NULL when the pps device is created, and if a |
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* client wants to use it, just fill it in afterward. |
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* |
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* The cookie is automatically set to NULL in pps_unregister_source() |
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* so that it will not be used again, even if the pps device cannot |
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* be removed from the idr due to pending references holding the minor |
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* number in use. |
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*/ |
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struct pps_device *pps_lookup_dev(void const *cookie) |
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{ |
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struct pps_device *pps; |
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unsigned id; |
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rcu_read_lock(); |
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idr_for_each_entry(&pps_idr, pps, id) |
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if (cookie == pps->lookup_cookie) |
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break; |
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rcu_read_unlock(); |
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return pps; |
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} |
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EXPORT_SYMBOL(pps_lookup_dev); |
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/* |
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* Module stuff |
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*/ |
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static void __exit pps_exit(void) |
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{ |
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class_destroy(pps_class); |
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unregister_chrdev_region(pps_devt, PPS_MAX_SOURCES); |
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} |
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static int __init pps_init(void) |
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{ |
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int err; |
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pps_class = class_create(THIS_MODULE, "pps"); |
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if (IS_ERR(pps_class)) { |
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pr_err("failed to allocate class\n"); |
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return PTR_ERR(pps_class); |
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} |
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pps_class->dev_groups = pps_groups; |
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err = alloc_chrdev_region(&pps_devt, 0, PPS_MAX_SOURCES, "pps"); |
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if (err < 0) { |
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pr_err("failed to allocate char device region\n"); |
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goto remove_class; |
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} |
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pr_info("LinuxPPS API ver. %d registered\n", PPS_API_VERS); |
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pr_info("Software ver. %s - Copyright 2005-2007 Rodolfo Giometti " |
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"<[email protected]>\n", PPS_VERSION); |
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return 0; |
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remove_class: |
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class_destroy(pps_class); |
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return err; |
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} |
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subsys_initcall(pps_init); |
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module_exit(pps_exit); |
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MODULE_AUTHOR("Rodolfo Giometti <[email protected]>"); |
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MODULE_DESCRIPTION("LinuxPPS support (RFC 2783) - ver. " PPS_VERSION); |
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MODULE_LICENSE("GPL");
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