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
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