rtc/hctosys: only claim the RTC provided the system time if it did

Without this patch /sys/class/rtc/$CONFIG_RTC_HCTOSYS_DEVICE/hctosys contains a 1 (meaning "This rtc was used to initialize the system clock") even if reading the time at bootup failed. Moreover change error handling in rtc_hctosys() to use goto and so reduce the indention level. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Cc: Paul Gortmaker <p_gortmaker@yahoo.com> Acked-by: Alessandro Zummo <a.zummo@towertech.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

rtc/hctosys: only claim the RTC provided the system time if it did
Without this patch /sys/class/rtc/$CONFIG_RTC_HCTOSYS_DEVICE/hctosys contains a 1 (meaning "This rtc was used to initialize the system clock") even if reading the time at bootup failed. Moreover change error handling in rtc_hctosys() to use goto and so reduce the indention level. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Cc: Paul Gortmaker <p_gortmaker@yahoo.com> Acked-by: Alessandro Zummo <a.zummo@towertech.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Uwe Kleine-König · Linus Torvalds
1 parent 019b4d123a
Showing 3 changed files with 43 additions and 27 deletions Side-by-side Diff
drivers/rtc/hctosys.c
drivers/rtc/rtc-sysfs.c
include/linux/rtc.h
@@ -22,48 +22,57 @@
  * the best guess is to add 0.5s.
  */
  
+int rtc_hctosys_ret = -ENODEV;
+
 static int __init rtc_hctosys(void)
 {
-	int err;
+	int err = -ENODEV;
 	struct rtc_time tm;
+	struct timespec tv = {
+		.tv_nsec = NSEC_PER_SEC >> 1,
+	};
 	struct rtc_device *rtc = rtc_class_open(CONFIG_RTC_HCTOSYS_DEVICE);
  
 	if (rtc == NULL) {
-		printk("%s: unable to open rtc device (%s)\n",
+		pr_err("%s: unable to open rtc device (%s)\n",
 			__FILE__, CONFIG_RTC_HCTOSYS_DEVICE);
-		return -ENODEV;
+		goto err_open;
 	}
  
 	err = rtc_read_time(rtc, &tm);
-	if (err == 0) {
-		err = rtc_valid_tm(&tm);
-		if (err == 0) {
-			struct timespec tv;
+	if (err) {
+		dev_err(rtc->dev.parent,
+			"hctosys: unable to read the hardware clock\n");
+		goto err_read;
  
-			tv.tv_nsec = NSEC_PER_SEC >> 1;
+	}
  
-			rtc_tm_to_time(&tm, &tv.tv_sec);
+	err = rtc_valid_tm(&tm);
+	if (err) {
+		dev_err(rtc->dev.parent,
+			"hctosys: invalid date/time\n");
+		goto err_invalid;
+	}
  
-			do_settimeofday(&tv);
+	rtc_tm_to_time(&tm, &tv.tv_sec);
  
-			dev_info(rtc->dev.parent,
-				"setting system clock to "
-				"%d-%02d-%02d %02d:%02d:%02d UTC (%u)\n",
-				tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
-				tm.tm_hour, tm.tm_min, tm.tm_sec,
-				(unsigned int) tv.tv_sec);
-		}
-		else
-			dev_err(rtc->dev.parent,
-				"hctosys: invalid date/time\n");
-	}
-	else
-		dev_err(rtc->dev.parent,
-			"hctosys: unable to read the hardware clock\n");
+	do_settimeofday(&tv);
  
+	dev_info(rtc->dev.parent,
+		"setting system clock to "
+		"%d-%02d-%02d %02d:%02d:%02d UTC (%u)\n",
+		tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
+		tm.tm_hour, tm.tm_min, tm.tm_sec,
+		(unsigned int) tv.tv_sec);
+
+err_invalid:
+err_read:
 	rtc_class_close(rtc);
  
-	return 0;
+err_open:
+	rtc_hctosys_ret = err;
+
+	return err;
 }
  
 late_initcall(rtc_hctosys);
@@ -107,8 +107,9 @@
 		char *buf)
 {
 #ifdef CONFIG_RTC_HCTOSYS_DEVICE
-	if (strcmp(dev_name(&to_rtc_device(dev)->dev),
-		   CONFIG_RTC_HCTOSYS_DEVICE) == 0)
+	if (rtc_hctosys_ret == 0 &&
+			strcmp(dev_name(&to_rtc_device(dev)->dev),
+				CONFIG_RTC_HCTOSYS_DEVICE) == 0)
 		return sprintf(buf, "1\n");
 	else
 #endif
@@ -238,6 +238,12 @@
 	return (!(year % 4) && (year % 100)) || !(year % 400);
 }
  
+#ifdef CONFIG_RTC_HCTOSYS
+extern int rtc_hctosys_ret;
+#else
+#define rtc_hctosys_ret -ENODEV
+#endif
+
 #endif /* __KERNEL__ */
  
 #endif /* _LINUX_RTC_H_ */
...	...	@@ -22,48 +22,57 @@
22	22	* the best guess is to add 0.5s.
23	23	*/
24	24
	25	+int rtc_hctosys_ret = -ENODEV;
	26	+
25	27	static int __init rtc_hctosys(void)
26	28	{
27		- int err;
	29	+ int err = -ENODEV;
28	30	struct rtc_time tm;
	31	+ struct timespec tv = {
	32	+ .tv_nsec = NSEC_PER_SEC >> 1,
	33	+ };
29	34	struct rtc_device *rtc = rtc_class_open(CONFIG_RTC_HCTOSYS_DEVICE);
30	35
31	36	if (rtc == NULL) {
32		- printk("%s: unable to open rtc device (%s)\n",
	37	+ pr_err("%s: unable to open rtc device (%s)\n",
33	38	__FILE__, CONFIG_RTC_HCTOSYS_DEVICE);
34		- return -ENODEV;
	39	+ goto err_open;
35	40	}
36	41
37	42	err = rtc_read_time(rtc, &tm);
38		- if (err == 0) {
39		- err = rtc_valid_tm(&tm);
40		- if (err == 0) {
41		- struct timespec tv;
	43	+ if (err) {
	44	+ dev_err(rtc->dev.parent,
	45	+ "hctosys: unable to read the hardware clock\n");
	46	+ goto err_read;
42	47
43		- tv.tv_nsec = NSEC_PER_SEC >> 1;
	48	+ }
44	49
45		- rtc_tm_to_time(&tm, &tv.tv_sec);
	50	+ err = rtc_valid_tm(&tm);
	51	+ if (err) {
	52	+ dev_err(rtc->dev.parent,
	53	+ "hctosys: invalid date/time\n");
	54	+ goto err_invalid;
	55	+ }
46	56
47		- do_settimeofday(&tv);
	57	+ rtc_tm_to_time(&tm, &tv.tv_sec);
48	58
49		- dev_info(rtc->dev.parent,
50		- "setting system clock to "
51		- "%d-%02d-%02d %02d:%02d:%02d UTC (%u)\n",
52		- tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
53		- tm.tm_hour, tm.tm_min, tm.tm_sec,
54		- (unsigned int) tv.tv_sec);
55		- }
56		- else
57		- dev_err(rtc->dev.parent,
58		- "hctosys: invalid date/time\n");
59		- }
60		- else
61		- dev_err(rtc->dev.parent,
62		- "hctosys: unable to read the hardware clock\n");
	59	+ do_settimeofday(&tv);
63	60
	61	+ dev_info(rtc->dev.parent,
	62	+ "setting system clock to "
	63	+ "%d-%02d-%02d %02d:%02d:%02d UTC (%u)\n",
	64	+ tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
	65	+ tm.tm_hour, tm.tm_min, tm.tm_sec,
	66	+ (unsigned int) tv.tv_sec);
	67	+
	68	+err_invalid:
	69	+err_read:
64	70	rtc_class_close(rtc);
65	71
66		- return 0;
	72	+err_open:
	73	+ rtc_hctosys_ret = err;
	74	+
	75	+ return err;
67	76	}
68	77
69	78	late_initcall(rtc_hctosys);
...	...	@@ -107,8 +107,9 @@
107	107	char *buf)
108	108	{
109	109	#ifdef CONFIG_RTC_HCTOSYS_DEVICE
110		- if (strcmp(dev_name(&to_rtc_device(dev)->dev),
111		- CONFIG_RTC_HCTOSYS_DEVICE) == 0)
	110	+ if (rtc_hctosys_ret == 0 &&
	111	+ strcmp(dev_name(&to_rtc_device(dev)->dev),
	112	+ CONFIG_RTC_HCTOSYS_DEVICE) == 0)
112	113	return sprintf(buf, "1\n");
113	114	else
114	115	#endif
...	...	@@ -238,6 +238,12 @@
238	238	return (!(year % 4) && (year % 100)) \|\| !(year % 400);
239	239	}
240	240
	241	+#ifdef CONFIG_RTC_HCTOSYS
	242	+extern int rtc_hctosys_ret;
	243	+#else
	244	+#define rtc_hctosys_ret -ENODEV
	245	+#endif
	246	+
241	247	#endif /* __KERNEL__ */
242	248
243	249	#endif /* _LINUX_RTC_H_ */