From mboxrd@z Thu Jan  1 00:00:00 1970
From: Shinya Kuribayashi <skuribay@ruby.dti.ne.jp>
Date: Sun, 25 May 2008 22:45:48 +0900
Subject: [U-Boot-Users] [PATCH 3/3][MIPS] lib_mips/time.c: Fix improper
 use of CFG_HZ and timer routines
In-Reply-To: <20080525081501.241BF247CC@gemini.denx.de>
References: <20080525081501.241BF247CC@gemini.denx.de>
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Wolfgang Denk wrote:
>> Sure. We'll probably need to move timer_init to board_init_r at the end.
> 
> I'm not sure if this works. We use udelay() and friends all over the
> place - a long time before that.

Hmm.

My udelay is already global-variable-free. And as for cycles_per_jiffy
and expirelo, we could make it work like this:

diff --git a/lib_mips/time.c b/lib_mips/time.c
index f6678e1..d4754e3 100644
--- a/lib_mips/time.c
+++ b/lib_mips/time.c
@@ -27,10 +27,7 @@
 static unsigned long timestamp;
 
 /* how many counter cycles in a jiffy */
-static unsigned long cycles_per_jiffy;
-
-/* expirelo is the count value for next CPU timer interrupt */
-static unsigned int expirelo;
+static unsigned long cycles_per_jiffy = (CONFIG_MIPS_TIMER_FREQ + CFG_HZ / 2) / CFG_HZ;
 
 /*
  * timer without interrupts
@@ -38,9 +35,6 @@ static unsigned int expirelo;
 
 int timer_init(void)
 {
-	/* Calculate cache parameters. */
-	cycles_per_jiffy = (CONFIG_MIPS_TIMER_FREQ + CFG_HZ / 2) / CFG_HZ;
-
 	/* Report the high precision timer rate for a reference. */
 	printf("Using %u.%03u MHz high precision timer.\n",
 	       ((CONFIG_MIPS_TIMER_FREQ + 500) / 1000) / 1000,
@@ -48,7 +42,7 @@ int timer_init(void)
 
 	/* Set up the timer for the first expiration. */
 	timestamp = 0;
-	expirelo = read_c0_count() + cycles_per_jiffy;
+	write_c0_compare(read_c0_count() + cycles_per_jiffy);
 
 	return 0;
 }
@@ -56,12 +50,13 @@ int timer_init(void)
 void reset_timer(void)
 {
 	timestamp = 0;
-	expirelo = read_c0_count() + cycles_per_jiffy;
+	write_c0_compare(read_c0_count() + cycles_per_jiffy);
 }
 
 ulong get_timer(ulong base)
 {
 	unsigned int count;
+	unsigned int expirelo = read_c0_compare();
 
 	/* Check to see if we have missed any timestamps. */
 	count = read_c0_count();
@@ -73,6 +68,7 @@ ulong get_timer(ulong base)
 		expirelo += cycles_per_jiffy;
 		timestamp++;
 	}
+	write_c0_compare(expirelo);
 
 	return (timestamp - base);
 }
@@ -80,7 +76,7 @@ ulong get_timer(ulong base)
 void set_timer(ulong t)
 {
 	timestamp = t;
-	expirelo = read_c0_count() + cycles_per_jiffy;
+	write_c0_compare(read_c0_count() + cycles_per_jiffy);
 }
 
 void udelay(unsigned long usec)
_


But I have no clue about timestamp.


> The timer implementation should have no such restrictions as being
> available only after relocation. Timers / delays are such a basic
> feature that they should be available everywhere.

I'll remember that.


  Shinya