1 files changed, 131 insertions, 72 deletions

diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c
index ac93b76f2b11..b1a2be1f9e3b 100644
--- a/drivers/rtc/class.c
+++ b/drivers/rtc/class.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * RTC subsystem, base class
  *
@@ -5,11 +6,7 @@
  * Author: Alessandro Zummo <a.zummo@towertech.it>
  *
  * class skeleton from drivers/hwmon/hwmon.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
 
@@ -23,20 +20,73 @@
 
 #include "rtc-core.h"
 
-
 static DEFINE_IDA(rtc_ida);
-struct class *rtc_class;
 
 static void rtc_device_release(struct device *dev)
 {
 	struct rtc_device *rtc = to_rtc_device(dev);
-	ida_simple_remove(&rtc_ida, rtc->id);
+	struct timerqueue_head *head = &rtc->timerqueue;
+	struct timerqueue_node *node;
+
+	mutex_lock(&rtc->ops_lock);
+	while ((node = timerqueue_getnext(head)))
+		timerqueue_del(head, node);
+	mutex_unlock(&rtc->ops_lock);
+
+	cancel_work_sync(&rtc->irqwork);
+
+	ida_free(&rtc_ida, rtc->id);
+	mutex_destroy(&rtc->ops_lock);
 	kfree(rtc);
 }
 
 #ifdef CONFIG_RTC_HCTOSYS_DEVICE
 /* Result of the last RTC to system clock attempt. */
 int rtc_hctosys_ret = -ENODEV;
+
+/* IMPORTANT: the RTC only stores whole seconds. It is arbitrary
+ * whether it stores the most close value or the value with partial
+ * seconds truncated. However, it is important that we use it to store
+ * the truncated value. This is because otherwise it is necessary,
+ * in an rtc sync function, to read both xtime.tv_sec and
+ * xtime.tv_nsec. On some processors (i.e. ARM), an atomic read
+ * of >32bits is not possible. So storing the most close value would
+ * slow down the sync API. So here we have the truncated value and
+ * the best guess is to add 0.5s.
+ */
+
+static void rtc_hctosys(struct rtc_device *rtc)
+{
+	int err;
+	struct rtc_time tm;
+	struct timespec64 tv64 = {
+		.tv_nsec = NSEC_PER_SEC >> 1,
+	};
+
+	err = rtc_read_time(rtc, &tm);
+	if (err) {
+		dev_err(rtc->dev.parent,
+			"hctosys: unable to read the hardware clock\n");
+		goto err_read;
+	}
+
+	tv64.tv_sec = rtc_tm_to_time64(&tm);
+
+#if BITS_PER_LONG == 32
+	if (tv64.tv_sec > INT_MAX) {
+		err = -ERANGE;
+		goto err_read;
+	}
+#endif
+
+	err = do_settimeofday64(&tv64);
+
+	dev_info(rtc->dev.parent, "setting system clock to %ptR UTC (%lld)\n",
+		 &tm, (long long)tv64.tv_sec);
+
+err_read:
+	rtc_hctosys_ret = err;
+}
 #endif
 
 #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
@@ -47,7 +97,6 @@ int rtc_hctosys_ret = -ENODEV;
 
 static struct timespec64 old_rtc, old_system, old_delta;
 
-
 static int rtc_suspend(struct device *dev)
 {
 	struct rtc_device	*rtc = to_rtc_device(dev);
@@ -71,7 +120,6 @@ static int rtc_suspend(struct device *dev)
 	ktime_get_real_ts64(&old_system);
 	old_rtc.tv_sec = rtc_tm_to_time64(&tm);
 
-
 	/*
 	 * To avoid drift caused by repeated suspend/resumes,
 	 * which each can add ~1 second drift error,
@@ -83,7 +131,7 @@ static int rtc_suspend(struct device *dev)
 	if (delta_delta.tv_sec < -2 || delta_delta.tv_sec >= 2) {
 		/*
 		 * if delta_delta is too large, assume time correction
-		 * has occured and set old_delta to the current delta.
+		 * has occurred and set old_delta to the current delta.
 		 */
 		old_delta = delta;
 	} else {
@@ -136,7 +184,7 @@ static int rtc_resume(struct device *dev)
 	 * to keep things accurate.
 	 */
 	sleep_time = timespec64_sub(sleep_time,
-			timespec64_sub(new_system, old_system));
+				    timespec64_sub(new_system, old_system));
 
 	if (sleep_time.tv_sec >= 0)
 		timekeeping_inject_sleeptime64(&sleep_time);
@@ -150,6 +198,11 @@ static SIMPLE_DEV_PM_OPS(rtc_class_dev_pm_ops, rtc_suspend, rtc_resume);
 #define RTC_CLASS_DEV_PM_OPS	NULL
 #endif
 
+const struct class rtc_class = {
+	.name = "rtc",
+	.pm = RTC_CLASS_DEV_PM_OPS,
+};
+
 /* Ensure the caller will set the id before releasing the device */
 static struct rtc_device *rtc_allocate_device(void)
 {
@@ -161,12 +214,17 @@ static struct rtc_device *rtc_allocate_device(void)
 
 	device_initialize(&rtc->dev);
 
-	/* Drivers can revise this default after allocating the device. */
-	rtc->set_offset_nsec =  NSEC_PER_SEC / 2;
+	/*
+	 * Drivers can revise this default after allocating the device.
+	 * The default is what most RTCs do: Increment seconds exactly one
+	 * second after the write happened. This adds a default transport
+	 * time of 5ms which is at least halfways close to reality.
+	 */
+	rtc->set_offset_nsec = NSEC_PER_SEC + 5 * NSEC_PER_MSEC;
 
 	rtc->irq_freq = 1;
 	rtc->max_user_freq = 64;
-	rtc->dev.class = rtc_class;
+	rtc->dev.class = &rtc_class;
 	rtc->dev.groups = rtc_get_dev_attribute_groups();
 	rtc->dev.release = rtc_device_release;
 
@@ -182,10 +240,12 @@ static struct rtc_device *rtc_allocate_device(void)
 	/* Init uie timer */
 	rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, rtc);
 	/* Init pie timer */
-	hrtimer_init(&rtc->pie_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
-	rtc->pie_timer.function = rtc_pie_update_irq;
+	hrtimer_setup(&rtc->pie_timer, rtc_pie_update_irq, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 	rtc->pie_enabled = 0;
 
+	set_bit(RTC_FEATURE_ALARM, rtc->features);
+	set_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features);
+
 	return rtc;
 }
 
@@ -199,13 +259,13 @@ static int rtc_device_get_id(struct device *dev)
 		of_id = of_alias_get_id(dev->parent->of_node, "rtc");
 
 	if (of_id >= 0) {
-		id = ida_simple_get(&rtc_ida, of_id, of_id + 1, GFP_KERNEL);
+		id = ida_alloc_range(&rtc_ida, of_id, of_id, GFP_KERNEL);
 		if (id < 0)
 			dev_warn(dev, "/aliases ID %d not available\n", of_id);
 	}
 
 	if (id < 0)
-		id = ida_simple_get(&rtc_ida, 0, 0, GFP_KERNEL);
+		id = ida_alloc(&rtc_ida, GFP_KERNEL);
 
 	return id;
 }
@@ -266,7 +326,7 @@ static void rtc_device_get_offset(struct rtc_device *rtc)
 	 *
 	 * Otherwise the offset seconds should be 0.
 	 */
-	if (rtc->start_secs > rtc->range_max ||
+	if ((rtc->start_secs >= 0 && rtc->start_secs > rtc->range_max) ||
 	    rtc->start_secs + range_secs - 1 < rtc->range_min)
 		rtc->offset_secs = rtc->start_secs - rtc->range_min;
 	else if (rtc->start_secs > rtc->range_min)
@@ -277,82 +337,73 @@ static void rtc_device_get_offset(struct rtc_device *rtc)
 		rtc->offset_secs = 0;
 }
 
-/**
- * rtc_device_unregister - removes the previously registered RTC class device
- *
- * @rtc: the RTC class device to destroy
- */
-static void rtc_device_unregister(struct rtc_device *rtc)
+static void devm_rtc_unregister_device(void *data)
 {
+	struct rtc_device *rtc = data;
+
 	mutex_lock(&rtc->ops_lock);
 	/*
 	 * Remove innards of this RTC, then disable it, before
 	 * letting any rtc_class_open() users access it again
 	 */
 	rtc_proc_del_device(rtc);
-	cdev_device_del(&rtc->char_dev, &rtc->dev);
+	if (!test_bit(RTC_NO_CDEV, &rtc->flags))
+		cdev_device_del(&rtc->char_dev, &rtc->dev);
 	rtc->ops = NULL;
 	mutex_unlock(&rtc->ops_lock);
-	put_device(&rtc->dev);
 }
 
-static void devm_rtc_release_device(struct device *dev, void *res)
+static void devm_rtc_release_device(void *res)
 {
-	struct rtc_device *rtc = *(struct rtc_device **)res;
+	struct rtc_device *rtc = res;
 
-	rtc_nvmem_unregister(rtc);
-
-	if (rtc->registered)
-		rtc_device_unregister(rtc);
-	else
-		put_device(&rtc->dev);
+	put_device(&rtc->dev);
 }
 
 struct rtc_device *devm_rtc_allocate_device(struct device *dev)
 {
-	struct rtc_device **ptr, *rtc;
+	struct rtc_device *rtc;
 	int id, err;
 
 	id = rtc_device_get_id(dev);
 	if (id < 0)
 		return ERR_PTR(id);
 
-	ptr = devres_alloc(devm_rtc_release_device, sizeof(*ptr), GFP_KERNEL);
-	if (!ptr) {
-		err = -ENOMEM;
-		goto exit_ida;
-	}
-
 	rtc = rtc_allocate_device();
 	if (!rtc) {
-		err = -ENOMEM;
-		goto exit_devres;
+		ida_free(&rtc_ida, id);
+		return ERR_PTR(-ENOMEM);
 	}
 
-	*ptr = rtc;
-	devres_add(dev, ptr);
-
 	rtc->id = id;
 	rtc->dev.parent = dev;
-	dev_set_name(&rtc->dev, "rtc%d", id);
+	err = devm_add_action_or_reset(dev, devm_rtc_release_device, rtc);
+	if (err)
+		return ERR_PTR(err);
 
-	return rtc;
+	err = dev_set_name(&rtc->dev, "rtc%d", id);
+	if (err)
+		return ERR_PTR(err);
 
-exit_devres:
-	devres_free(ptr);
-exit_ida:
-	ida_simple_remove(&rtc_ida, id);
-	return ERR_PTR(err);
+	return rtc;
 }
 EXPORT_SYMBOL_GPL(devm_rtc_allocate_device);
 
-int __rtc_register_device(struct module *owner, struct rtc_device *rtc)
+int __devm_rtc_register_device(struct module *owner, struct rtc_device *rtc)
 {
 	struct rtc_wkalrm alrm;
 	int err;
 
-	if (!rtc->ops)
+	if (!rtc->ops) {
+		dev_dbg(&rtc->dev, "no ops set\n");
 		return -EINVAL;
+	}
+
+	if (!rtc->ops->set_alarm)
+		clear_bit(RTC_FEATURE_ALARM, rtc->features);
+
+	if (rtc->ops->set_offset)
+		set_bit(RTC_FEATURE_CORRECTION, rtc->features);
 
 	rtc->owner = owner;
 	rtc_device_get_offset(rtc);
@@ -365,22 +416,29 @@ int __rtc_register_device(struct module *owner, struct rtc_device *rtc)
 	rtc_dev_prepare(rtc);
 
 	err = cdev_device_add(&rtc->char_dev, &rtc->dev);
-	if (err)
+	if (err) {
+		set_bit(RTC_NO_CDEV, &rtc->flags);
 		dev_warn(rtc->dev.parent, "failed to add char device %d:%d\n",
 			 MAJOR(rtc->dev.devt), rtc->id);
-	else
+	} else {
 		dev_dbg(rtc->dev.parent, "char device (%d:%d)\n",
 			MAJOR(rtc->dev.devt), rtc->id);
+	}
 
 	rtc_proc_add_device(rtc);
 
-	rtc->registered = true;
 	dev_info(rtc->dev.parent, "registered as %s\n",
 		 dev_name(&rtc->dev));
 
-	return 0;
+#ifdef CONFIG_RTC_HCTOSYS_DEVICE
+	if (!strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE))
+		rtc_hctosys(rtc);
+#endif
+
+	return devm_add_action_or_reset(rtc->dev.parent,
+					devm_rtc_unregister_device, rtc);
 }
-EXPORT_SYMBOL_GPL(__rtc_register_device);
+EXPORT_SYMBOL_GPL(__devm_rtc_register_device);
 
 /**
  * devm_rtc_device_register - resource managed rtc_device_register()
@@ -397,9 +455,9 @@ EXPORT_SYMBOL_GPL(__rtc_register_device);
  * rtc_register_device instead
  */
 struct rtc_device *devm_rtc_device_register(struct device *dev,
-					const char *name,
-					const struct rtc_class_ops *ops,
-					struct module *owner)
+					    const char *name,
+					    const struct rtc_class_ops *ops,
+					    struct module *owner)
 {
 	struct rtc_device *rtc;
 	int err;
@@ -410,7 +468,7 @@ struct rtc_device *devm_rtc_device_register(struct device *dev,
 
 	rtc->ops = ops;
 
-	err = __rtc_register_device(owner, rtc);
+	err = __devm_rtc_register_device(owner, rtc);
 	if (err)
 		return ERR_PTR(err);
 
@@ -420,13 +478,14 @@ EXPORT_SYMBOL_GPL(devm_rtc_device_register);
 
 static int __init rtc_init(void)
 {
-	rtc_class = class_create(THIS_MODULE, "rtc");
-	if (IS_ERR(rtc_class)) {
-		pr_err("couldn't create class\n");
-		return PTR_ERR(rtc_class);
-	}
-	rtc_class->pm = RTC_CLASS_DEV_PM_OPS;
+	int err;
+
+	err = class_register(&rtc_class);
+	if (err)
+		return err;
+
 	rtc_dev_init();
+
 	return 0;
 }
 subsys_initcall(rtc_init);