--- zzzz-none-000/linux-3.10.107/drivers/rtc/rtc-efi.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/drivers/rtc/rtc-efi.c	2021-02-04 17:41:59.000000000 +0000
@@ -3,7 +3,7 @@
  *
  * Copyright (C) 2009 Hewlett-Packard Development Company, L.P.
  *
- * Author: dann frazier <dannf@hp.com>
+ * Author: dann frazier <dannf@dannf.org>
  * Based on efirtc.c by Stephane Eranian
  *
  *  This program is free software; you can redistribute  it and/or modify it
@@ -17,16 +17,13 @@
 
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/stringify.h>
 #include <linux/time.h>
 #include <linux/platform_device.h>
 #include <linux/rtc.h>
 #include <linux/efi.h>
 
 #define EFI_ISDST (EFI_TIME_ADJUST_DAYLIGHT|EFI_TIME_IN_DAYLIGHT)
-/*
- * EFI Epoch is 1/1/1998
- */
-#define EFI_RTC_EPOCH		1998
 
 /*
  * returns day of the year [0-365]
@@ -35,33 +32,26 @@
 compute_yday(efi_time_t *eft)
 {
 	/* efi_time_t.month is in the [1-12] so, we need -1 */
-	return rtc_year_days(eft->day - 1, eft->month - 1, eft->year);
+	return rtc_year_days(eft->day, eft->month - 1, eft->year);
 }
+
 /*
  * returns day of the week [0-6] 0=Sunday
- *
- * Don't try to provide a year that's before 1998, please !
  */
 static int
-compute_wday(efi_time_t *eft)
+compute_wday(efi_time_t *eft, int yday)
 {
-	int y;
-	int ndays = 0;
-
-	if (eft->year < 1998) {
-		pr_err("EFI year < 1998, invalid date\n");
-		return -1;
-	}
-
-	for (y = EFI_RTC_EPOCH; y < eft->year; y++)
-		ndays += 365 + (is_leap_year(y) ? 1 : 0);
-
-	ndays += compute_yday(eft);
+	int ndays = eft->year * (365 % 7)
+		    + (eft->year - 1) / 4
+		    - (eft->year - 1) / 100
+		    + (eft->year - 1) / 400
+		    + yday;
 
 	/*
-	 * 4=1/1/1998 was a Thursday
+	 * 1/1/0000 may or may not have been a Sunday (if it ever existed at
+	 * all) but assuming it was makes this calculation work correctly.
 	 */
-	return (ndays + 4) % 7;
+	return ndays % 7;
 }
 
 static void
@@ -78,23 +68,40 @@
 	eft->timezone	= EFI_UNSPECIFIED_TIMEZONE;
 }
 
-static void
+static bool
 convert_from_efi_time(efi_time_t *eft, struct rtc_time *wtime)
 {
 	memset(wtime, 0, sizeof(*wtime));
+
+	if (eft->second >= 60)
+		return false;
 	wtime->tm_sec  = eft->second;
+
+	if (eft->minute >= 60)
+		return false;
 	wtime->tm_min  = eft->minute;
+
+	if (eft->hour >= 24)
+		return false;
 	wtime->tm_hour = eft->hour;
+
+	if (!eft->day || eft->day > 31)
+		return false;
 	wtime->tm_mday = eft->day;
+
+	if (!eft->month || eft->month > 12)
+		return false;
 	wtime->tm_mon  = eft->month - 1;
-	wtime->tm_year = eft->year - 1900;
 
-	/* day of the week [0-6], Sunday=0 */
-	wtime->tm_wday = compute_wday(eft);
+	if (eft->year < 1900 || eft->year > 9999)
+		return false;
+	wtime->tm_year = eft->year - 1900;
 
 	/* day in the year [1-365]*/
 	wtime->tm_yday = compute_yday(eft);
 
+	/* day of the week [0-6], Sunday=0 */
+	wtime->tm_wday = compute_wday(eft, wtime->tm_yday);
 
 	switch (eft->daylight & EFI_ISDST) {
 	case EFI_ISDST:
@@ -106,6 +113,8 @@
 	default:
 		wtime->tm_isdst = -1;
 	}
+
+	return true;
 }
 
 static int efi_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
@@ -122,7 +131,8 @@
 	if (status != EFI_SUCCESS)
 		return -EINVAL;
 
-	convert_from_efi_time(&eft, &wkalrm->time);
+	if (!convert_from_efi_time(&eft, &wkalrm->time))
+		return -EIO;
 
 	return rtc_valid_tm(&wkalrm->time);
 }
@@ -163,7 +173,8 @@
 		return -EINVAL;
 	}
 
-	convert_from_efi_time(&eft, tm);
+	if (!convert_from_efi_time(&eft, tm))
+		return -EIO;
 
 	return rtc_valid_tm(tm);
 }
@@ -196,26 +207,22 @@
 	if (IS_ERR(rtc))
 		return PTR_ERR(rtc);
 
+	rtc->uie_unsupported = 1;
 	platform_set_drvdata(dev, rtc);
 
 	return 0;
 }
 
-static int __exit efi_rtc_remove(struct platform_device *dev)
-{
-	return 0;
-}
-
 static struct platform_driver efi_rtc_driver = {
 	.driver = {
 		.name = "rtc-efi",
-		.owner = THIS_MODULE,
 	},
-	.remove = __exit_p(efi_rtc_remove),
 };
 
 module_platform_driver_probe(efi_rtc_driver, efi_rtc_probe);
 
-MODULE_AUTHOR("dann frazier <dannf@hp.com>");
+MODULE_ALIAS("platform:rtc-efi");
+MODULE_AUTHOR("dann frazier <dannf@dannf.org>");
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("EFI RTC driver");
+MODULE_ALIAS("platform:rtc-efi");