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From: Matt Mackall <mpm@selenic.com>
To: Andrew Morton <akpm@osdl.org>
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH 8/14] RTC: Remove RTC UIP synchronization on MIPS MC146818
Date: Fri, 17 Mar 2006 17:30:36 -0600	[thread overview]
Message-ID: <9.132654658@selenic.com> (raw)
In-Reply-To: <2.132654658@selenic.com>

Remove RTC UIP synchronization on MIPS MC146818

Signed-off-by: Matt Mackall <mpm@selenic.com>

Index: rtc/include/asm-mips/mc146818-time.h
===================================================================
--- rtc.orig/include/asm-mips/mc146818-time.h	2006-03-16 16:47:28.000000000 -0600
+++ rtc/include/asm-mips/mc146818-time.h	2006-03-16 17:25:54.000000000 -0600
@@ -86,43 +86,14 @@ static inline int mc146818_set_rtc_mmss(
 	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);

  parent reply	other threads:[~2006-03-18  0:00 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-03-17 23:30 [PATCH 1/14] RTC: Remove RTC UIP synchronization on x86 Matt Mackall
2006-03-17 23:30 ` [PATCH 4/14] RTC: Remove RTC UIP synchronization on PPC CHRP (arch/ppc) Matt Mackall
2006-03-17 23:30 ` [PATCH 2/14] RTC: Remove RTC UIP synchronization on x86_64 Matt Mackall
2006-03-18  5:52   ` Andrew Morton
2006-03-18 14:16     ` Matt Mackall
2006-03-17 23:30 ` [PATCH 3/14] RTC: Remove RTC UIP synchronization on Sparc64 Matt Mackall
2006-03-17 23:30 ` Matt Mackall [this message]
2006-03-17 23:30 ` [PATCH 6/14] RTC: Remove RTC UIP synchronization on PPC Maple Matt Mackall
2006-03-17 23:30 ` [PATCH 7/14] RTC: Remove RTC UIP synchronization on MIPS Footbridge Matt Mackall
2006-03-17 23:58   ` Matt Mackall
2006-03-17 23:30 ` [PATCH 5/14] RTC: Remove RTC UIP synchronization on CHRP (arch/powerpc) Matt Mackall
2006-03-17 23:30 ` [PATCH 11/14] RTC: Remove RTC UIP synchronization on SH MPC1211 Matt Mackall
2006-03-17 23:30 ` [PATCH 10/14] RTC: Remove RTC UIP synchronization on SH03 Matt Mackall
2006-03-17 23:30 ` [PATCH 9/14] RTC: Remove RTC UIP synchronization on MIPS-based DEC Matt Mackall
2006-03-17 23:30 ` [PATCH 12/14] RTC: Remove RTC UIP synchronization on Alpha Matt Mackall
2006-03-17 23:30 ` [PATCH 13/14] RTC: Fix up some RTC whitespace and style Matt Mackall
2006-03-17 23:30 ` [PATCH 14/14] RTC: Remove some duplicate BCD definitions Matt Mackall
2006-03-18  5:53   ` Andrew Morton
2006-03-19 18:13 ` [PATCH 1/14] RTC: Remove RTC UIP synchronization on x86 Pavel Machek
2006-03-21 16:38   ` Matt Mackall
2006-03-21 18:40     ` Pavel Machek

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