headers: remove sched.h from interrupt.h
[safe/jmp/linux-2.6] / drivers / rtc / interface.c
index 56e4907..a0c8162 100644 (file)
 */
 
 #include <linux/rtc.h>
+#include <linux/sched.h>
+#include <linux/log2.h>
 
-int rtc_read_time(struct class_device *class_dev, struct rtc_time *tm)
+int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
 {
        int err;
-       struct rtc_device *rtc = to_rtc_device(class_dev);
 
        err = mutex_lock_interruptible(&rtc->ops_lock);
        if (err)
-               return -EBUSY;
+               return err;
 
        if (!rtc->ops)
                err = -ENODEV;
@@ -28,7 +29,7 @@ int rtc_read_time(struct class_device *class_dev, struct rtc_time *tm)
                err = -EINVAL;
        else {
                memset(tm, 0, sizeof(struct rtc_time));
-               err = rtc->ops->read_time(class_dev->dev, tm);
+               err = rtc->ops->read_time(rtc->dev.parent, tm);
        }
 
        mutex_unlock(&rtc->ops_lock);
@@ -36,10 +37,9 @@ int rtc_read_time(struct class_device *class_dev, struct rtc_time *tm)
 }
 EXPORT_SYMBOL_GPL(rtc_read_time);
 
-int rtc_set_time(struct class_device *class_dev, struct rtc_time *tm)
+int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm)
 {
        int err;
-       struct rtc_device *rtc = to_rtc_device(class_dev);
 
        err = rtc_valid_tm(tm);
        if (err != 0)
@@ -47,37 +47,41 @@ int rtc_set_time(struct class_device *class_dev, struct rtc_time *tm)
 
        err = mutex_lock_interruptible(&rtc->ops_lock);
        if (err)
-               return -EBUSY;
+               return err;
 
        if (!rtc->ops)
                err = -ENODEV;
-       else if (!rtc->ops->set_time)
+       else if (rtc->ops->set_time)
+               err = rtc->ops->set_time(rtc->dev.parent, tm);
+       else if (rtc->ops->set_mmss) {
+               unsigned long secs;
+               err = rtc_tm_to_time(tm, &secs);
+               if (err == 0)
+                       err = rtc->ops->set_mmss(rtc->dev.parent, secs);
+       } else
                err = -EINVAL;
-       else
-               err = rtc->ops->set_time(class_dev->dev, tm);
 
        mutex_unlock(&rtc->ops_lock);
        return err;
 }
 EXPORT_SYMBOL_GPL(rtc_set_time);
 
-int rtc_set_mmss(struct class_device *class_dev, unsigned long secs)
+int rtc_set_mmss(struct rtc_device *rtc, unsigned long secs)
 {
        int err;
-       struct rtc_device *rtc = to_rtc_device(class_dev);
 
        err = mutex_lock_interruptible(&rtc->ops_lock);
        if (err)
-               return -EBUSY;
+               return err;
 
        if (!rtc->ops)
                err = -ENODEV;
        else if (rtc->ops->set_mmss)
-               err = rtc->ops->set_mmss(class_dev->dev, secs);
+               err = rtc->ops->set_mmss(rtc->dev.parent, secs);
        else if (rtc->ops->read_time && rtc->ops->set_time) {
                struct rtc_time new, old;
 
-               err = rtc->ops->read_time(class_dev->dev, &old);
+               err = rtc->ops->read_time(rtc->dev.parent, &old);
                if (err == 0) {
                        rtc_time_to_tm(secs, &new);
 
@@ -89,7 +93,8 @@ int rtc_set_mmss(struct class_device *class_dev, unsigned long secs)
                         */
                        if (!((old.tm_hour == 23 && old.tm_min == 59) ||
                                (new.tm_hour == 23 && new.tm_min == 59)))
-                               err = rtc->ops->set_time(class_dev->dev, &new);
+                               err = rtc->ops->set_time(rtc->dev.parent,
+                                               &new);
                }
        }
        else
@@ -101,14 +106,13 @@ int rtc_set_mmss(struct class_device *class_dev, unsigned long secs)
 }
 EXPORT_SYMBOL_GPL(rtc_set_mmss);
 
-int rtc_read_alarm(struct class_device *class_dev, struct rtc_wkalrm *alarm)
+static int rtc_read_alarm_internal(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
 {
        int err;
-       struct rtc_device *rtc = to_rtc_device(class_dev);
 
        err = mutex_lock_interruptible(&rtc->ops_lock);
        if (err)
-               return -EBUSY;
+               return err;
 
        if (rtc->ops == NULL)
                err = -ENODEV;
@@ -116,162 +120,410 @@ int rtc_read_alarm(struct class_device *class_dev, struct rtc_wkalrm *alarm)
                err = -EINVAL;
        else {
                memset(alarm, 0, sizeof(struct rtc_wkalrm));
-               err = rtc->ops->read_alarm(class_dev->dev, alarm);
+               err = rtc->ops->read_alarm(rtc->dev.parent, alarm);
        }
 
        mutex_unlock(&rtc->ops_lock);
        return err;
 }
+
+int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
+{
+       int err;
+       struct rtc_time before, now;
+       int first_time = 1;
+       unsigned long t_now, t_alm;
+       enum { none, day, month, year } missing = none;
+       unsigned days;
+
+       /* The lower level RTC driver may return -1 in some fields,
+        * creating invalid alarm->time values, for reasons like:
+        *
+        *   - The hardware may not be capable of filling them in;
+        *     many alarms match only on time-of-day fields, not
+        *     day/month/year calendar data.
+        *
+        *   - Some hardware uses illegal values as "wildcard" match
+        *     values, which non-Linux firmware (like a BIOS) may try
+        *     to set up as e.g. "alarm 15 minutes after each hour".
+        *     Linux uses only oneshot alarms.
+        *
+        * When we see that here, we deal with it by using values from
+        * a current RTC timestamp for any missing (-1) values.  The
+        * RTC driver prevents "periodic alarm" modes.
+        *
+        * But this can be racey, because some fields of the RTC timestamp
+        * may have wrapped in the interval since we read the RTC alarm,
+        * which would lead to us inserting inconsistent values in place
+        * of the -1 fields.
+        *
+        * Reading the alarm and timestamp in the reverse sequence
+        * would have the same race condition, and not solve the issue.
+        *
+        * So, we must first read the RTC timestamp,
+        * then read the RTC alarm value,
+        * and then read a second RTC timestamp.
+        *
+        * If any fields of the second timestamp have changed
+        * when compared with the first timestamp, then we know
+        * our timestamp may be inconsistent with that used by
+        * the low-level rtc_read_alarm_internal() function.
+        *
+        * So, when the two timestamps disagree, we just loop and do
+        * the process again to get a fully consistent set of values.
+        *
+        * This could all instead be done in the lower level driver,
+        * but since more than one lower level RTC implementation needs it,
+        * then it's probably best best to do it here instead of there..
+        */
+
+       /* Get the "before" timestamp */
+       err = rtc_read_time(rtc, &before);
+       if (err < 0)
+               return err;
+       do {
+               if (!first_time)
+                       memcpy(&before, &now, sizeof(struct rtc_time));
+               first_time = 0;
+
+               /* get the RTC alarm values, which may be incomplete */
+               err = rtc_read_alarm_internal(rtc, alarm);
+               if (err)
+                       return err;
+               if (!alarm->enabled)
+                       return 0;
+
+               /* full-function RTCs won't have such missing fields */
+               if (rtc_valid_tm(&alarm->time) == 0)
+                       return 0;
+
+               /* get the "after" timestamp, to detect wrapped fields */
+               err = rtc_read_time(rtc, &now);
+               if (err < 0)
+                       return err;
+
+               /* note that tm_sec is a "don't care" value here: */
+       } while (   before.tm_min   != now.tm_min
+                || before.tm_hour  != now.tm_hour
+                || before.tm_mon   != now.tm_mon
+                || before.tm_year  != now.tm_year);
+
+       /* Fill in the missing alarm fields using the timestamp; we
+        * know there's at least one since alarm->time is invalid.
+        */
+       if (alarm->time.tm_sec == -1)
+               alarm->time.tm_sec = now.tm_sec;
+       if (alarm->time.tm_min == -1)
+               alarm->time.tm_min = now.tm_min;
+       if (alarm->time.tm_hour == -1)
+               alarm->time.tm_hour = now.tm_hour;
+
+       /* For simplicity, only support date rollover for now */
+       if (alarm->time.tm_mday == -1) {
+               alarm->time.tm_mday = now.tm_mday;
+               missing = day;
+       }
+       if (alarm->time.tm_mon == -1) {
+               alarm->time.tm_mon = now.tm_mon;
+               if (missing == none)
+                       missing = month;
+       }
+       if (alarm->time.tm_year == -1) {
+               alarm->time.tm_year = now.tm_year;
+               if (missing == none)
+                       missing = year;
+       }
+
+       /* with luck, no rollover is needed */
+       rtc_tm_to_time(&now, &t_now);
+       rtc_tm_to_time(&alarm->time, &t_alm);
+       if (t_now < t_alm)
+               goto done;
+
+       switch (missing) {
+
+       /* 24 hour rollover ... if it's now 10am Monday, an alarm that
+        * that will trigger at 5am will do so at 5am Tuesday, which
+        * could also be in the next month or year.  This is a common
+        * case, especially for PCs.
+        */
+       case day:
+               dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day");
+               t_alm += 24 * 60 * 60;
+               rtc_time_to_tm(t_alm, &alarm->time);
+               break;
+
+       /* Month rollover ... if it's the 31th, an alarm on the 3rd will
+        * be next month.  An alarm matching on the 30th, 29th, or 28th
+        * may end up in the month after that!  Many newer PCs support
+        * this type of alarm.
+        */
+       case month:
+               dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month");
+               do {
+                       if (alarm->time.tm_mon < 11)
+                               alarm->time.tm_mon++;
+                       else {
+                               alarm->time.tm_mon = 0;
+                               alarm->time.tm_year++;
+                       }
+                       days = rtc_month_days(alarm->time.tm_mon,
+                                       alarm->time.tm_year);
+               } while (days < alarm->time.tm_mday);
+               break;
+
+       /* Year rollover ... easy except for leap years! */
+       case year:
+               dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year");
+               do {
+                       alarm->time.tm_year++;
+               } while (rtc_valid_tm(&alarm->time) != 0);
+               break;
+
+       default:
+               dev_warn(&rtc->dev, "alarm rollover not handled\n");
+       }
+
+done:
+       return 0;
+}
 EXPORT_SYMBOL_GPL(rtc_read_alarm);
 
-int rtc_set_alarm(struct class_device *class_dev, struct rtc_wkalrm *alarm)
+int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
 {
        int err;
-       struct rtc_device *rtc = to_rtc_device(class_dev);
+
+       err = rtc_valid_tm(&alarm->time);
+       if (err != 0)
+               return err;
 
        err = mutex_lock_interruptible(&rtc->ops_lock);
        if (err)
-               return -EBUSY;
+               return err;
 
        if (!rtc->ops)
                err = -ENODEV;
        else if (!rtc->ops->set_alarm)
                err = -EINVAL;
        else
-               err = rtc->ops->set_alarm(class_dev->dev, alarm);
+               err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
 
        mutex_unlock(&rtc->ops_lock);
        return err;
 }
 EXPORT_SYMBOL_GPL(rtc_set_alarm);
 
-void rtc_update_irq(struct class_device *class_dev,
+int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
+{
+       int err = mutex_lock_interruptible(&rtc->ops_lock);
+       if (err)
+               return err;
+
+       if (!rtc->ops)
+               err = -ENODEV;
+       else if (!rtc->ops->alarm_irq_enable)
+               err = -EINVAL;
+       else
+               err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled);
+
+       mutex_unlock(&rtc->ops_lock);
+       return err;
+}
+EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable);
+
+int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
+{
+       int err = mutex_lock_interruptible(&rtc->ops_lock);
+       if (err)
+               return err;
+
+#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
+       if (enabled == 0 && rtc->uie_irq_active) {
+               mutex_unlock(&rtc->ops_lock);
+               return rtc_dev_update_irq_enable_emul(rtc, enabled);
+       }
+#endif
+
+       if (!rtc->ops)
+               err = -ENODEV;
+       else if (!rtc->ops->update_irq_enable)
+               err = -EINVAL;
+       else
+               err = rtc->ops->update_irq_enable(rtc->dev.parent, enabled);
+
+       mutex_unlock(&rtc->ops_lock);
+
+#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
+       /*
+        * Enable emulation if the driver did not provide
+        * the update_irq_enable function pointer or if returned
+        * -EINVAL to signal that it has been configured without
+        * interrupts or that are not available at the moment.
+        */
+       if (err == -EINVAL)
+               err = rtc_dev_update_irq_enable_emul(rtc, enabled);
+#endif
+       return err;
+}
+EXPORT_SYMBOL_GPL(rtc_update_irq_enable);
+
+/**
+ * rtc_update_irq - report RTC periodic, alarm, and/or update irqs
+ * @rtc: the rtc device
+ * @num: how many irqs are being reported (usually one)
+ * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
+ * Context: any
+ */
+void rtc_update_irq(struct rtc_device *rtc,
                unsigned long num, unsigned long events)
 {
-       struct rtc_device *rtc = to_rtc_device(class_dev);
+       unsigned long flags;
 
-       spin_lock(&rtc->irq_lock);
+       spin_lock_irqsave(&rtc->irq_lock, flags);
        rtc->irq_data = (rtc->irq_data + (num << 8)) | events;
-       spin_unlock(&rtc->irq_lock);
+       spin_unlock_irqrestore(&rtc->irq_lock, flags);
 
-       spin_lock(&rtc->irq_task_lock);
+       spin_lock_irqsave(&rtc->irq_task_lock, flags);
        if (rtc->irq_task)
                rtc->irq_task->func(rtc->irq_task->private_data);
-       spin_unlock(&rtc->irq_task_lock);
+       spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
 
        wake_up_interruptible(&rtc->irq_queue);
        kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
 }
 EXPORT_SYMBOL_GPL(rtc_update_irq);
 
-struct class_device *rtc_class_open(char *name)
+static int __rtc_match(struct device *dev, void *data)
 {
-       struct class_device *class_dev = NULL,
-                               *class_dev_tmp;
-
-       down(&rtc_class->sem);
-       list_for_each_entry(class_dev_tmp, &rtc_class->children, node) {
-               if (strncmp(class_dev_tmp->class_id, name, BUS_ID_SIZE) == 0) {
-                       class_dev = class_dev_tmp;
-                       break;
-               }
-       }
+       char *name = (char *)data;
 
-       if (class_dev) {
-               if (!try_module_get(to_rtc_device(class_dev)->owner))
-                       class_dev = NULL;
+       if (strcmp(dev_name(dev), name) == 0)
+               return 1;
+       return 0;
+}
+
+struct rtc_device *rtc_class_open(char *name)
+{
+       struct device *dev;
+       struct rtc_device *rtc = NULL;
+
+       dev = class_find_device(rtc_class, NULL, name, __rtc_match);
+       if (dev)
+               rtc = to_rtc_device(dev);
+
+       if (rtc) {
+               if (!try_module_get(rtc->owner)) {
+                       put_device(dev);
+                       rtc = NULL;
+               }
        }
-       up(&rtc_class->sem);
 
-       return class_dev;
+       return rtc;
 }
 EXPORT_SYMBOL_GPL(rtc_class_open);
 
-void rtc_class_close(struct class_device *class_dev)
+void rtc_class_close(struct rtc_device *rtc)
 {
-       module_put(to_rtc_device(class_dev)->owner);
+       module_put(rtc->owner);
+       put_device(&rtc->dev);
 }
 EXPORT_SYMBOL_GPL(rtc_class_close);
 
-int rtc_irq_register(struct class_device *class_dev, struct rtc_task *task)
+int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task)
 {
        int retval = -EBUSY;
-       struct rtc_device *rtc = to_rtc_device(class_dev);
 
        if (task == NULL || task->func == NULL)
                return -EINVAL;
 
-       spin_lock(&rtc->irq_task_lock);
+       /* Cannot register while the char dev is in use */
+       if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
+               return -EBUSY;
+
+       spin_lock_irq(&rtc->irq_task_lock);
        if (rtc->irq_task == NULL) {
                rtc->irq_task = task;
                retval = 0;
        }
-       spin_unlock(&rtc->irq_task_lock);
+       spin_unlock_irq(&rtc->irq_task_lock);
+
+       clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
 
        return retval;
 }
 EXPORT_SYMBOL_GPL(rtc_irq_register);
 
-void rtc_irq_unregister(struct class_device *class_dev, struct rtc_task *task)
+void rtc_irq_unregister(struct rtc_device *rtc, struct rtc_task *task)
 {
-       struct rtc_device *rtc = to_rtc_device(class_dev);
-
-       spin_lock(&rtc->irq_task_lock);
+       spin_lock_irq(&rtc->irq_task_lock);
        if (rtc->irq_task == task)
                rtc->irq_task = NULL;
-       spin_unlock(&rtc->irq_task_lock);
+       spin_unlock_irq(&rtc->irq_task_lock);
 }
 EXPORT_SYMBOL_GPL(rtc_irq_unregister);
 
-int rtc_irq_set_state(struct class_device *class_dev, struct rtc_task *task, int enabled)
+/**
+ * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
+ * @rtc: the rtc device
+ * @task: currently registered with rtc_irq_register()
+ * @enabled: true to enable periodic IRQs
+ * Context: any
+ *
+ * Note that rtc_irq_set_freq() should previously have been used to
+ * specify the desired frequency of periodic IRQ task->func() callbacks.
+ */
+int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled)
 {
        int err = 0;
        unsigned long flags;
-       struct rtc_device *rtc = to_rtc_device(class_dev);
+
+       if (rtc->ops->irq_set_state == NULL)
+               return -ENXIO;
 
        spin_lock_irqsave(&rtc->irq_task_lock, flags);
+       if (rtc->irq_task != NULL && task == NULL)
+               err = -EBUSY;
        if (rtc->irq_task != task)
-               err = -ENXIO;
+               err = -EACCES;
        spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
 
        if (err == 0)
-               err = rtc->ops->irq_set_state(class_dev->dev, enabled);
+               err = rtc->ops->irq_set_state(rtc->dev.parent, enabled);
 
        return err;
 }
 EXPORT_SYMBOL_GPL(rtc_irq_set_state);
 
-int rtc_irq_set_freq(struct class_device *class_dev, struct rtc_task *task, int freq)
+/**
+ * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
+ * @rtc: the rtc device
+ * @task: currently registered with rtc_irq_register()
+ * @freq: positive frequency with which task->func() will be called
+ * Context: any
+ *
+ * Note that rtc_irq_set_state() is used to enable or disable the
+ * periodic IRQs.
+ */
+int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq)
 {
-       int err = 0, tmp = 0;
+       int err = 0;
        unsigned long flags;
-       struct rtc_device *rtc = to_rtc_device(class_dev);
 
-       /* allowed range is 2-8192 */
-       if (freq < 2 || freq > 8192)
-               return -EINVAL;
-/*
-       FIXME: this does not belong here, will move where appropriate
-       at a later stage. It cannot hurt right now, trust me :)
-       if ((freq > rtc_max_user_freq) && (!capable(CAP_SYS_RESOURCE)))
-               return -EACCES;
-*/
-       /* check if freq is a power of 2 */
-       while (freq > (1 << tmp))
-               tmp++;
-
-       if (freq != (1 << tmp))
-               return -EINVAL;
+       if (rtc->ops->irq_set_freq == NULL)
+               return -ENXIO;
 
        spin_lock_irqsave(&rtc->irq_task_lock, flags);
+       if (rtc->irq_task != NULL && task == NULL)
+               err = -EBUSY;
        if (rtc->irq_task != task)
-               err = -ENXIO;
+               err = -EACCES;
        spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
 
        if (err == 0) {
-               err = rtc->ops->irq_set_freq(class_dev->dev, freq);
+               err = rtc->ops->irq_set_freq(rtc->dev.parent, freq);
                if (err == 0)
                        rtc->irq_freq = freq;
        }
        return err;
 }
+EXPORT_SYMBOL_GPL(rtc_irq_set_freq);