1 files changed, 124 insertions, 7 deletions

diff --git a/drivers/rtc/rtc-dev.c b/drivers/rtc/rtc-dev.c
index 2011567005f..61a58259c93 100644
--- a/drivers/rtc/rtc-dev.c
+++ b/drivers/rtc/rtc-dev.c
@@ -48,6 +48,93 @@ static int rtc_dev_open(struct inode *inode, struct file *file)
         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(void *data)
+{
+        struct rtc_device *rtc = data;
+        struct rtc_time tm;
+        int num = 0;
+        int err;
+
+        err = rtc_read_time(&rtc->class_dev, &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_update_irq(&rtc->class_dev, num, RTC_UF | RTC_IRQF);
+}
+
+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 void clear_uie(struct rtc_device *rtc)
+{
+        spin_lock_irq(&rtc->irq_lock);
+        if (rtc->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->irq_active = 0;
+        }
+        spin_unlock_irq(&rtc->irq_lock);
+}
+
+static int set_uie(struct rtc_device *rtc)
+{
+        struct rtc_time tm;
+        int err;
+
+        err = rtc_read_time(&rtc->class_dev, &tm);
+        if (err)
+                return err;
+        spin_lock_irq(&rtc->irq_lock);
+        if (!rtc->irq_active) {
+                rtc->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;
+}
+#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)
@@ -127,6 +214,28 @@ static int rtc_dev_ioctl(struct inode *inode, struct file *file,
         struct rtc_wkalrm alarm;
         void __user *uarg = (void __user *) arg;
 
+        /* check that the calles 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))
+                        return -EACCES;
+                break;
+
+        case RTC_IRQP_SET:
+                if (arg > rtc->max_user_freq && !capable(CAP_SYS_RESOURCE))
+                        return -EACCES;
+                break;
+
+        case RTC_PIE_ON:
+                if (!capable(CAP_SYS_RESOURCE))
+                        return -EACCES;
+                break;
+        }
+
         /* avoid conflicting IRQ users */
         if (cmd == RTC_PIE_ON || cmd == RTC_PIE_OFF || cmd == RTC_IRQP_SET) {
                 spin_lock(&rtc->irq_task_lock);
@@ -185,9 +294,6 @@ static int rtc_dev_ioctl(struct inode *inode, struct file *file,
                 break;
 
         case RTC_SET_TIME:
-                if (!capable(CAP_SYS_TIME))
-                        return -EACCES;
-
                 if (copy_from_user(&tm, uarg, sizeof(tm)))
                         return -EFAULT;
 
@@ -203,10 +309,6 @@ static int rtc_dev_ioctl(struct inode *inode, struct file *file,
                         err = -EINVAL;
                         break;
                 }
-                if (!capable(CAP_SYS_TIME)) {
-                        err = -EACCES;
-                        break;
-                }
                 rtc_epoch = arg;
                 err = 0;
 #endif
@@ -232,6 +334,14 @@ static int rtc_dev_ioctl(struct inode *inode, struct file *file,
                         return -EFAULT;
                 break;
 
+#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
+        case RTC_UIE_OFF:
+                clear_uie(rtc);
+                return 0;
+
+        case RTC_UIE_ON:
+                return set_uie(rtc);
+#endif
         default:
                 err = -ENOTTY;
                 break;
@@ -244,6 +354,9 @@ static int rtc_dev_release(struct inode *inode, struct file *file)
 {
         struct rtc_device *rtc = to_rtc_device(file->private_data);
 
+#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
+        clear_uie(rtc);
+#endif
         if (rtc->ops->release)
                 rtc->ops->release(rtc->class_dev.dev);
 
@@ -284,6 +397,10 @@ static int rtc_dev_add_device(struct class_device *class_dev,
         mutex_init(&rtc->char_lock);
         spin_lock_init(&rtc->irq_lock);
         init_waitqueue_head(&rtc->irq_queue);
+#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
+        INIT_WORK(&rtc->uie_task, rtc_uie_task, rtc);
+        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;