I've checked the TOY programming on a board Au1100 based and I notice
that the frequency is not correct. Infact the TOY frequency is just
HZ/2... I suggest this patch that should fix this topic.
The patch also try to fix (in a poor manner) a problem related with
the jiffie_drift and the fact that HZ may be in the range [100:1000].
The last block (@@ -189,15 +196,11 @@) remove a bug during system wake
up when HZ is 1000. The while() may loose too much time computing the
last_match20 parameter and if TOY must run at 1K the system hangs
since the TOY is programmed with an alredy passed time stamp.
Ciao,
Rodolfo
Index: common/time.c
===================================================================
RCS file: /home/develop/cvs_private/linux-mips-exadron/arch/mips/au1000/common/time.c,v
retrieving revision 1.3
diff -u -r1.3 time.c
--- a/common/time.c 26 Jul 2005 21:33:32 -0000 1.3
+++ b/common/time.c 29 Mar 2006 15:26:03 -0000
@@ -142,7 +143,7 @@
time_elapsed = pc0 - last_match20;
}
- while (time_elapsed > 0) {
+ do {
do_timer(regs);
#ifndef CONFIG_SMP
update_process_times(user_mode(regs));
@@ -150,14 +151,19 @@
time_elapsed -= MATCH20_INC;
last_match20 += MATCH20_INC;
jiffie_drift++;
- }
+ } while (time_elapsed > MATCH20_INC);
last_pc0 = pc0;
au_writel(last_match20 + MATCH20_INC, SYS_TOYMATCH2);
au_sync();
- /* our counter ticks at 10.009765625 ms/tick, we we're running
- * almost 10uS too slow per tick.
+#if HZ < 400
+ /* our counter ticks at
+ * HZ = 100 -> 10.009765625 ms/tick
+ * HZ = 400 -> 2.50244140625 ms/tick
+ * HZ = 500 -> 1.983642578125 ms/tick
+ * HZ = 1000 -> 0.9765625 ms/tick
+ * so HZ = 400 may be a good discriminating point...
*/
if (jiffie_drift >= 999) {
@@ -167,6 +173,7 @@
update_process_times(user_mode(regs));
#endif
}
+#endif
return IRQ_HANDLED;
}
@@ -189,15 +196,11 @@
time_elapsed = pc0 - last_match20;
}
- while (time_elapsed > 0) {
- time_elapsed -= MATCH20_INC;
- last_match20 += MATCH20_INC;
- }
+ last_match20 += time_elapsed - time_elapsed%MATCH20_INC;
last_pc0 = pc0;
au_writel(last_match20 + MATCH20_INC, SYS_TOYMATCH2);
au_sync();
-
}
/* This is just for debugging to set the timer for a sleep delay.
--
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Embedded Systems giometti@xxxxxxxx
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