Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / drivers / rtc / rtc-dev.c
diff --git a/kernel/drivers/rtc/rtc-dev.c b/kernel/drivers/rtc/rtc-dev.c
new file mode 100644 (file)
index 0000000..799c34b
--- /dev/null
@@ -0,0 +1,511 @@
+/*
+ * RTC subsystem, dev interface
+ *
+ * Copyright (C) 2005 Tower Technologies
+ * Author: Alessandro Zummo <a.zummo@towertech.it>
+ *
+ * based on arch/arm/common/rtctime.c
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+*/
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/rtc.h>
+#include <linux/sched.h>
+#include "rtc-core.h"
+
+static dev_t rtc_devt;
+
+#define RTC_DEV_MAX 16 /* 16 RTCs should be enough for everyone... */
+
+static int rtc_dev_open(struct inode *inode, struct file *file)
+{
+       int err;
+       struct rtc_device *rtc = container_of(inode->i_cdev,
+                                       struct rtc_device, char_dev);
+       const struct rtc_class_ops *ops = rtc->ops;
+
+       if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
+               return -EBUSY;
+
+       file->private_data = rtc;
+
+       err = ops->open ? ops->open(rtc->dev.parent) : 0;
+       if (err == 0) {
+               spin_lock_irq(&rtc->irq_lock);
+               rtc->irq_data = 0;
+               spin_unlock_irq(&rtc->irq_lock);
+
+               return 0;
+       }
+
+       /* something has gone wrong */
+       clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
+       return err;
+}
+
+#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
+/*
+ * Routine to poll RTC seconds field for change as often as possible,
+ * after first RTC_UIE use timer to reduce polling
+ */
+static void rtc_uie_task(struct work_struct *work)
+{
+       struct rtc_device *rtc =
+               container_of(work, struct rtc_device, uie_task);
+       struct rtc_time tm;
+       int num = 0;
+       int err;
+
+       err = rtc_read_time(rtc, &tm);
+
+       spin_lock_irq(&rtc->irq_lock);
+       if (rtc->stop_uie_polling || err) {
+               rtc->uie_task_active = 0;
+       } else if (rtc->oldsecs != tm.tm_sec) {
+               num = (tm.tm_sec + 60 - rtc->oldsecs) % 60;
+               rtc->oldsecs = tm.tm_sec;
+               rtc->uie_timer.expires = jiffies + HZ - (HZ/10);
+               rtc->uie_timer_active = 1;
+               rtc->uie_task_active = 0;
+               add_timer(&rtc->uie_timer);
+       } else if (schedule_work(&rtc->uie_task) == 0) {
+               rtc->uie_task_active = 0;
+       }
+       spin_unlock_irq(&rtc->irq_lock);
+       if (num)
+               rtc_handle_legacy_irq(rtc, num, RTC_UF);
+}
+static void rtc_uie_timer(unsigned long data)
+{
+       struct rtc_device *rtc = (struct rtc_device *)data;
+       unsigned long flags;
+
+       spin_lock_irqsave(&rtc->irq_lock, flags);
+       rtc->uie_timer_active = 0;
+       rtc->uie_task_active = 1;
+       if ((schedule_work(&rtc->uie_task) == 0))
+               rtc->uie_task_active = 0;
+       spin_unlock_irqrestore(&rtc->irq_lock, flags);
+}
+
+static int clear_uie(struct rtc_device *rtc)
+{
+       spin_lock_irq(&rtc->irq_lock);
+       if (rtc->uie_irq_active) {
+               rtc->stop_uie_polling = 1;
+               if (rtc->uie_timer_active) {
+                       spin_unlock_irq(&rtc->irq_lock);
+                       del_timer_sync(&rtc->uie_timer);
+                       spin_lock_irq(&rtc->irq_lock);
+                       rtc->uie_timer_active = 0;
+               }
+               if (rtc->uie_task_active) {
+                       spin_unlock_irq(&rtc->irq_lock);
+                       flush_scheduled_work();
+                       spin_lock_irq(&rtc->irq_lock);
+               }
+               rtc->uie_irq_active = 0;
+       }
+       spin_unlock_irq(&rtc->irq_lock);
+       return 0;
+}
+
+static int set_uie(struct rtc_device *rtc)
+{
+       struct rtc_time tm;
+       int err;
+
+       err = rtc_read_time(rtc, &tm);
+       if (err)
+               return err;
+       spin_lock_irq(&rtc->irq_lock);
+       if (!rtc->uie_irq_active) {
+               rtc->uie_irq_active = 1;
+               rtc->stop_uie_polling = 0;
+               rtc->oldsecs = tm.tm_sec;
+               rtc->uie_task_active = 1;
+               if (schedule_work(&rtc->uie_task) == 0)
+                       rtc->uie_task_active = 0;
+       }
+       rtc->irq_data = 0;
+       spin_unlock_irq(&rtc->irq_lock);
+       return 0;
+}
+
+int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc, unsigned int enabled)
+{
+       if (enabled)
+               return set_uie(rtc);
+       else
+               return clear_uie(rtc);
+}
+EXPORT_SYMBOL(rtc_dev_update_irq_enable_emul);
+
+#endif /* CONFIG_RTC_INTF_DEV_UIE_EMUL */
+
+static ssize_t
+rtc_dev_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
+{
+       struct rtc_device *rtc = file->private_data;
+
+       DECLARE_WAITQUEUE(wait, current);
+       unsigned long data;
+       ssize_t ret;
+
+       if (count != sizeof(unsigned int) && count < sizeof(unsigned long))
+               return -EINVAL;
+
+       add_wait_queue(&rtc->irq_queue, &wait);
+       do {
+               __set_current_state(TASK_INTERRUPTIBLE);
+
+               spin_lock_irq(&rtc->irq_lock);
+               data = rtc->irq_data;
+               rtc->irq_data = 0;
+               spin_unlock_irq(&rtc->irq_lock);
+
+               if (data != 0) {
+                       ret = 0;
+                       break;
+               }
+               if (file->f_flags & O_NONBLOCK) {
+                       ret = -EAGAIN;
+                       break;
+               }
+               if (signal_pending(current)) {
+                       ret = -ERESTARTSYS;
+                       break;
+               }
+               schedule();
+       } while (1);
+       set_current_state(TASK_RUNNING);
+       remove_wait_queue(&rtc->irq_queue, &wait);
+
+       if (ret == 0) {
+               /* Check for any data updates */
+               if (rtc->ops->read_callback)
+                       data = rtc->ops->read_callback(rtc->dev.parent,
+                                                      data);
+
+               if (sizeof(int) != sizeof(long) &&
+                   count == sizeof(unsigned int))
+                       ret = put_user(data, (unsigned int __user *)buf) ?:
+                               sizeof(unsigned int);
+               else
+                       ret = put_user(data, (unsigned long __user *)buf) ?:
+                               sizeof(unsigned long);
+       }
+       return ret;
+}
+
+static unsigned int rtc_dev_poll(struct file *file, poll_table *wait)
+{
+       struct rtc_device *rtc = file->private_data;
+       unsigned long data;
+
+       poll_wait(file, &rtc->irq_queue, wait);
+
+       data = rtc->irq_data;
+
+       return (data != 0) ? (POLLIN | POLLRDNORM) : 0;
+}
+
+static long rtc_dev_ioctl(struct file *file,
+               unsigned int cmd, unsigned long arg)
+{
+       int err = 0;
+       struct rtc_device *rtc = file->private_data;
+       const struct rtc_class_ops *ops = rtc->ops;
+       struct rtc_time tm;
+       struct rtc_wkalrm alarm;
+       void __user *uarg = (void __user *) arg;
+
+       err = mutex_lock_interruptible(&rtc->ops_lock);
+       if (err)
+               return err;
+
+       /* check that the calling task has appropriate permissions
+        * for certain ioctls. doing this check here is useful
+        * to avoid duplicate code in each driver.
+        */
+       switch (cmd) {
+       case RTC_EPOCH_SET:
+       case RTC_SET_TIME:
+               if (!capable(CAP_SYS_TIME))
+                       err = -EACCES;
+               break;
+
+       case RTC_IRQP_SET:
+               if (arg > rtc->max_user_freq && !capable(CAP_SYS_RESOURCE))
+                       err = -EACCES;
+               break;
+
+       case RTC_PIE_ON:
+               if (rtc->irq_freq > rtc->max_user_freq &&
+                               !capable(CAP_SYS_RESOURCE))
+                       err = -EACCES;
+               break;
+       }
+
+       if (err)
+               goto done;
+
+       /*
+        * Drivers *SHOULD NOT* provide ioctl implementations
+        * for these requests.  Instead, provide methods to
+        * support the following code, so that the RTC's main
+        * features are accessible without using ioctls.
+        *
+        * RTC and alarm times will be in UTC, by preference,
+        * but dual-booting with MS-Windows implies RTCs must
+        * use the local wall clock time.
+        */
+
+       switch (cmd) {
+       case RTC_ALM_READ:
+               mutex_unlock(&rtc->ops_lock);
+
+               err = rtc_read_alarm(rtc, &alarm);
+               if (err < 0)
+                       return err;
+
+               if (copy_to_user(uarg, &alarm.time, sizeof(tm)))
+                       err = -EFAULT;
+               return err;
+
+       case RTC_ALM_SET:
+               mutex_unlock(&rtc->ops_lock);
+
+               if (copy_from_user(&alarm.time, uarg, sizeof(tm)))
+                       return -EFAULT;
+
+               alarm.enabled = 0;
+               alarm.pending = 0;
+               alarm.time.tm_wday = -1;
+               alarm.time.tm_yday = -1;
+               alarm.time.tm_isdst = -1;
+
+               /* RTC_ALM_SET alarms may be up to 24 hours in the future.
+                * Rather than expecting every RTC to implement "don't care"
+                * for day/month/year fields, just force the alarm to have
+                * the right values for those fields.
+                *
+                * RTC_WKALM_SET should be used instead.  Not only does it
+                * eliminate the need for a separate RTC_AIE_ON call, it
+                * doesn't have the "alarm 23:59:59 in the future" race.
+                *
+                * NOTE:  some legacy code may have used invalid fields as
+                * wildcards, exposing hardware "periodic alarm" capabilities.
+                * Not supported here.
+                */
+               {
+                       time64_t now, then;
+
+                       err = rtc_read_time(rtc, &tm);
+                       if (err < 0)
+                               return err;
+                       now = rtc_tm_to_time64(&tm);
+
+                       alarm.time.tm_mday = tm.tm_mday;
+                       alarm.time.tm_mon = tm.tm_mon;
+                       alarm.time.tm_year = tm.tm_year;
+                       err  = rtc_valid_tm(&alarm.time);
+                       if (err < 0)
+                               return err;
+                       then = rtc_tm_to_time64(&alarm.time);
+
+                       /* alarm may need to wrap into tomorrow */
+                       if (then < now) {
+                               rtc_time64_to_tm(now + 24 * 60 * 60, &tm);
+                               alarm.time.tm_mday = tm.tm_mday;
+                               alarm.time.tm_mon = tm.tm_mon;
+                               alarm.time.tm_year = tm.tm_year;
+                       }
+               }
+
+               return rtc_set_alarm(rtc, &alarm);
+
+       case RTC_RD_TIME:
+               mutex_unlock(&rtc->ops_lock);
+
+               err = rtc_read_time(rtc, &tm);
+               if (err < 0)
+                       return err;
+
+               if (copy_to_user(uarg, &tm, sizeof(tm)))
+                       err = -EFAULT;
+               return err;
+
+       case RTC_SET_TIME:
+               mutex_unlock(&rtc->ops_lock);
+
+               if (copy_from_user(&tm, uarg, sizeof(tm)))
+                       return -EFAULT;
+
+               return rtc_set_time(rtc, &tm);
+
+       case RTC_PIE_ON:
+               err = rtc_irq_set_state(rtc, NULL, 1);
+               break;
+
+       case RTC_PIE_OFF:
+               err = rtc_irq_set_state(rtc, NULL, 0);
+               break;
+
+       case RTC_AIE_ON:
+               mutex_unlock(&rtc->ops_lock);
+               return rtc_alarm_irq_enable(rtc, 1);
+
+       case RTC_AIE_OFF:
+               mutex_unlock(&rtc->ops_lock);
+               return rtc_alarm_irq_enable(rtc, 0);
+
+       case RTC_UIE_ON:
+               mutex_unlock(&rtc->ops_lock);
+               return rtc_update_irq_enable(rtc, 1);
+
+       case RTC_UIE_OFF:
+               mutex_unlock(&rtc->ops_lock);
+               return rtc_update_irq_enable(rtc, 0);
+
+       case RTC_IRQP_SET:
+               err = rtc_irq_set_freq(rtc, NULL, arg);
+               break;
+
+       case RTC_IRQP_READ:
+               err = put_user(rtc->irq_freq, (unsigned long __user *)uarg);
+               break;
+
+       case RTC_WKALM_SET:
+               mutex_unlock(&rtc->ops_lock);
+               if (copy_from_user(&alarm, uarg, sizeof(alarm)))
+                       return -EFAULT;
+
+               return rtc_set_alarm(rtc, &alarm);
+
+       case RTC_WKALM_RD:
+               mutex_unlock(&rtc->ops_lock);
+               err = rtc_read_alarm(rtc, &alarm);
+               if (err < 0)
+                       return err;
+
+               if (copy_to_user(uarg, &alarm, sizeof(alarm)))
+                       err = -EFAULT;
+               return err;
+
+       default:
+               /* Finally try the driver's ioctl interface */
+               if (ops->ioctl) {
+                       err = ops->ioctl(rtc->dev.parent, cmd, arg);
+                       if (err == -ENOIOCTLCMD)
+                               err = -ENOTTY;
+               } else
+                       err = -ENOTTY;
+               break;
+       }
+
+done:
+       mutex_unlock(&rtc->ops_lock);
+       return err;
+}
+
+static int rtc_dev_fasync(int fd, struct file *file, int on)
+{
+       struct rtc_device *rtc = file->private_data;
+       return fasync_helper(fd, file, on, &rtc->async_queue);
+}
+
+static int rtc_dev_release(struct inode *inode, struct file *file)
+{
+       struct rtc_device *rtc = file->private_data;
+
+       /* We shut down the repeating IRQs that userspace enabled,
+        * since nothing is listening to them.
+        *  - Update (UIE) ... currently only managed through ioctls
+        *  - Periodic (PIE) ... also used through rtc_*() interface calls
+        *
+        * Leave the alarm alone; it may be set to trigger a system wakeup
+        * later, or be used by kernel code, and is a one-shot event anyway.
+        */
+
+       /* Keep ioctl until all drivers are converted */
+       rtc_dev_ioctl(file, RTC_UIE_OFF, 0);
+       rtc_update_irq_enable(rtc, 0);
+       rtc_irq_set_state(rtc, NULL, 0);
+
+       if (rtc->ops->release)
+               rtc->ops->release(rtc->dev.parent);
+
+       clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
+       return 0;
+}
+
+static const struct file_operations rtc_dev_fops = {
+       .owner          = THIS_MODULE,
+       .llseek         = no_llseek,
+       .read           = rtc_dev_read,
+       .poll           = rtc_dev_poll,
+       .unlocked_ioctl = rtc_dev_ioctl,
+       .open           = rtc_dev_open,
+       .release        = rtc_dev_release,
+       .fasync         = rtc_dev_fasync,
+};
+
+/* insertion/removal hooks */
+
+void rtc_dev_prepare(struct rtc_device *rtc)
+{
+       if (!rtc_devt)
+               return;
+
+       if (rtc->id >= RTC_DEV_MAX) {
+               dev_dbg(&rtc->dev, "%s: too many RTC devices\n", rtc->name);
+               return;
+       }
+
+       rtc->dev.devt = MKDEV(MAJOR(rtc_devt), rtc->id);
+
+#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
+       INIT_WORK(&rtc->uie_task, rtc_uie_task);
+       setup_timer(&rtc->uie_timer, rtc_uie_timer, (unsigned long)rtc);
+#endif
+
+       cdev_init(&rtc->char_dev, &rtc_dev_fops);
+       rtc->char_dev.owner = rtc->owner;
+}
+
+void rtc_dev_add_device(struct rtc_device *rtc)
+{
+       if (cdev_add(&rtc->char_dev, rtc->dev.devt, 1))
+               dev_warn(&rtc->dev, "%s: failed to add char device %d:%d\n",
+                       rtc->name, MAJOR(rtc_devt), rtc->id);
+       else
+               dev_dbg(&rtc->dev, "%s: dev (%d:%d)\n", rtc->name,
+                       MAJOR(rtc_devt), rtc->id);
+}
+
+void rtc_dev_del_device(struct rtc_device *rtc)
+{
+       if (rtc->dev.devt)
+               cdev_del(&rtc->char_dev);
+}
+
+void __init rtc_dev_init(void)
+{
+       int err;
+
+       err = alloc_chrdev_region(&rtc_devt, 0, RTC_DEV_MAX, "rtc");
+       if (err < 0)
+               pr_err("failed to allocate char dev region\n");
+}
+
+void __exit rtc_dev_exit(void)
+{
+       if (rtc_devt)
+               unregister_chrdev_region(rtc_devt, RTC_DEV_MAX);
+}