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#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 int pps_major;static const struct class pps_class = { .name = "pps", .dev_groups = pps_groups};
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);
if (pps->last_fetched_ev == pps->last_ev) return 0;
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 { struct timespec64 ts; unsigned long ticks;
dev_dbg(&pps->dev, "timeout %lld.%09d\n", (long long) fdata->timeout.sec, fdata->timeout.nsec);
if (fdata->timeout.sec < 0) return -ETIMEDOUT;
ts.tv_sec = fdata->timeout.sec; ts.tv_nsec = fdata->timeout.nsec; ticks = timespec64_to_jiffies(&ts);
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, ¶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;
/* * Clear unused fields of pps_kparams to avoid leaking * uninitialized data of the PPS_SETPARAMS caller via * PPS_GETPARAMS */ pps->params.assert_off_tu.flags = 0; pps->params.clear_off_tu.flags = 0;
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 and save last fetched event */ spin_lock_irq(&pps->lock);
pps->last_fetched_ev = pps->last_ev;
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_COMPATstatic 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 and save last fetched event */ spin_lock_irq(&pps->lock);
pps->last_fetched_ev = pps->last_ev;
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 struct pps_device *pps_idr_get(unsigned long id){ struct pps_device *pps;
mutex_lock(&pps_idr_lock); pps = idr_find(&pps_idr, id); if (pps) get_device(&pps->dev);
mutex_unlock(&pps_idr_lock); return pps;}
static int pps_cdev_open(struct inode *inode, struct file *file){ struct pps_device *pps = pps_idr_get(iminor(inode));
if (!pps) 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;
WARN_ON(pps->id != iminor(inode)); put_device(&pps->dev); return 0;}
/* * Char device stuff */
static const struct file_operations pps_cdev_fops = { .owner = THIS_MODULE, .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);
pr_debug("deallocating pps%d\n", pps->id); kfree(pps);}
int pps_register_cdev(struct pps_device *pps){ int err;
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; } kfree(pps); goto out_unlock; } pps->id = err;
pps->dev.class = &pps_class; pps->dev.parent = pps->info.dev; pps->dev.devt = MKDEV(pps_major, pps->id); dev_set_drvdata(&pps->dev, pps); dev_set_name(&pps->dev, "pps%d", pps->id); pps->dev.release = pps_device_destruct; err = device_register(&pps->dev); if (err) goto free_idr;
pr_debug("source %s got cdev (%d:%d)\n", pps->info.name, pps_major, pps->id);
get_device(&pps->dev); mutex_unlock(&pps_idr_lock); return 0;
free_idr: idr_remove(&pps_idr, pps->id); put_device(&pps->dev);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);
/* Now we can release the ID for re-use */ mutex_lock(&pps_idr_lock); idr_remove(&pps_idr, pps->id); put_device(&pps->dev); mutex_unlock(&pps_idr_lock);}
/* * 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. * * Since pps_idr holds a reference to the device, the returned * pps_device is guaranteed to be valid until pps_unregister_cdev() is * called on it. But after calling pps_unregister_cdev(), it may be * freed at any time. */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_unregister(&pps_class); __unregister_chrdev(pps_major, 0, PPS_MAX_SOURCES, "pps");}
static int __init pps_init(void){ int err;
err = class_register(&pps_class); if (err) { pr_err("failed to register class\n"); return err; }
pps_major = __register_chrdev(0, 0, PPS_MAX_SOURCES, "pps", &pps_cdev_fops); if (pps_major < 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_unregister(&pps_class); return pps_major;}
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");