Niklaus Giger wrote:
Am Samstag, 23. September 2006 22:55 schrieb Wolfgang Grandegger:
Hi Niklaus,
Niklaus Giger wrote:
<..>
if (flags & IPIPE_RESET_TIMER)
ticks = tb_ticks_per_jiffy;
else {
ticks = ns * tb_ticks_per_jiffy / (1000000000 / HZ);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
if (ticks > tb_ticks_per_jiffy)
return -EINVAL;
<..>
Does replacing the calculation of ticks with
ticks = ns * (tb_ticks_per_jiffy / 10000) / (100000 / HZ);
help. A proper calculation might use mulhwu or rthal_imuldiv.
Yes. I does. There are two occurrences fixed with the attached patch (+ one
small ifdef to eliminate a compiler warning in the PPC40x case).
Timing is okay as tested with a small vxworks test program.
Could someone please apply it?
Thanks for your cooperation.
Best regards
------------------------------------------------------------------------
Index: ksrc/arch/powerpc/patches/adeos-ipipe-2.6.14-ppc-1.4-00.patch
===================================================================
--- ksrc/arch/powerpc/patches/adeos-ipipe-2.6.14-ppc-1.4-00.patch
(Revision 1650)
+++ ksrc/arch/powerpc/patches/adeos-ipipe-2.6.14-ppc-1.4-00.patch
(Arbeitskopie)
@@ -3595,7 +3595,7 @@
+ if (flags & IPIPE_RESET_TIMER)
+ ticks = tb_ticks_per_jiffy;
+ else {
-+ ticks = ns * tb_ticks_per_jiffy / (1000000000 / HZ);
++ ticks = ns * (tb_ticks_per_jiffy / 10000) / (100000 / HZ);
+
+ if (ticks > tb_ticks_per_jiffy)
+ return -EINVAL;
Index: ksrc/arch/powerpc/hal.c
===================================================================
--- ksrc/arch/powerpc/hal.c (Revision 1650)
+++ ksrc/arch/powerpc/hal.c (Arbeitskopie)
@@ -81,7 +81,9 @@
*/
static void rthal_set_local_cpu_timer(void)
{
+#ifndef CONFIG_40x
long ticks;
+#endif
rthal_declare_cpuid;
rthal_load_cpuid();
@@ -110,7 +112,7 @@
if (ns == 0)
ticks = tb_ticks_per_jiffy;
else {
- ticks = ns * tb_ticks_per_jiffy / (1000000000 / HZ);
+ ticks = ns * (tb_ticks_per_jiffy / 10000) / (100000 / HZ);
if (ticks > tb_ticks_per_jiffy) {
DBG("rthal_set_cpu_timers_unsafe: -EINVAL (%lu)\n", ticks);
My suggested fix was just to locate the source of the problem. As
Philippe suggested, we should use mulhwu (or mulhwu_scale_factor). Have
a look to arch/ppc/kernel/time.c for further information.
Wolfgang.
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