From: Matt Mackall <mpm@selenic.com>
Date: Tue, 28 Mar 2006 09:56:05 +0000 (-0800)
Subject: [PATCH] RTC: Remove RTC UIP synchronization on MIPS MC146818
X-Git-Tag: v2.6.17-rc1~266
X-Git-Url: http://www.pilppa.org/gitweb/gitweb.cgi?a=commitdiff_plain;h=da2468b6a81884a696fd6c7ab66dcc62d7233d32;p=linux-2.6-omap-h63xx.git

[PATCH] RTC: Remove RTC UIP synchronization on MIPS MC146818

Signed-off-by: Matt Mackall <mpm@selenic.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/include/asm-mips/mc146818-time.h b/include/asm-mips/mc146818-time.h
index 47214861093..41ac8d363c6 100644
--- a/include/asm-mips/mc146818-time.h
+++ b/include/asm-mips/mc146818-time.h
@@ -86,43 +86,14 @@ static inline int mc146818_set_rtc_mmss(unsigned long nowtime)
 	return retval;
 }
 
-/*
- * Returns true if a clock update is in progress
- */
-static inline unsigned char rtc_is_updating(void)
-{
-	unsigned char uip;
-	unsigned long flags;
-
-	spin_lock_irqsave(&rtc_lock, flags);
-	uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP);
-	spin_unlock_irqrestore(&rtc_lock, flags);
-	return uip;
-}
-
 static inline unsigned long mc146818_get_cmos_time(void)
 {
 	unsigned int year, mon, day, hour, min, sec;
-	int i;
 	unsigned long flags;
 
-	/*
-	 * The Linux interpretation of the CMOS clock register contents:
-	 * When the Update-In-Progress (UIP) flag goes from 1 to 0, the
-	 * RTC registers show the second which has precisely just started.
-	 * Let's hope other operating systems interpret the RTC the same way.
-	 */
-
-	/* read RTC exactly on falling edge of update flag */
-	for (i = 0 ; i < 1000000 ; i++)	/* may take up to 1 second... */
-		if (rtc_is_updating())
-			break;
-	for (i = 0 ; i < 1000000 ; i++)	/* must try at least 2.228 ms */
-		if (!rtc_is_updating())
-			break;
-
 	spin_lock_irqsave(&rtc_lock, flags);
-	do { /* Isn't this overkill ? UIP above should guarantee consistency */
+
+	do {
 		sec = CMOS_READ(RTC_SECONDS);
 		min = CMOS_READ(RTC_MINUTES);
 		hour = CMOS_READ(RTC_HOURS);