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Subject[RFC] [PATCH] linux-2.5.59_cyclone-fixes_A0
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All, 
In order for the timer_cyclone.c code to be enabled, the following
issues need to be remedied.

1) fast_gettimeoffset_quotient (initialized in timer_tsc->init()) is
used outside of timer_tsc.c Thus it either needs to be made static or
initialized in timer_cyclone.c

2) cpu_khz is only initialized in timer_tsc->init(). Either timer_tsc
needs to initialize in timer_tsc as well, or it needs to be initialized
outside the timer subsystem.

Now I have more "proper" patches for these issues, which makes
fast_gettimeoffset_quotient static and initializes cpu_khz in
cpu/common.c (which could be later expanded to making cpu_khz per-cpu).

However these patches move a reasonable amount of code around and touch
generic code in a number of places. So instead I've created this patch
as a "quick-fix" by duplicating some of the timer_tsc->init() code into
timer_cyclone->init(). This way we can still enable the timer_cyclone
code w/o touching any generic code (well, I do have to un-static
calibrate_tsc())

Honestly, I'm not super happy about doing it this way, but I do realize
the slush needs to thicken. However, I will continue to push the cleanup
patches, but this way the cyclone code won't depend on them.

Comments, suggestions and flames welcome.

thanks
-john


diff -Nru a/arch/i386/kernel/timers/timer_cyclone.c b/arch/i386/kernel/timers/timer_cyclone.c
--- a/arch/i386/kernel/timers/timer_cyclone.c Wed Jan 22 13:35:09 2003
+++ b/arch/i386/kernel/timers/timer_cyclone.c Wed Jan 22 13:35:09 2003
@@ -17,7 +17,7 @@
#include <asm/fixmap.h>

extern spinlock_t i8253_lock;
-
+extern unsigned long fast_gettimeoffset_quotient;
/* Number of usecs that the last interrupt was delayed */
static int delay_at_last_interrupt;

@@ -142,6 +142,28 @@
printk(KERN_ERR "Summit chipset: Counter not counting! DISABLED\n");
cyclone_timer = 0;
return -ENODEV;
+ }
+ }
+
+ /* init fast_gettimeoffset_quotent and cpu_khz.
+ * XXX - This should really be done elsewhere,
+ * and in a more generic fashion. -johnstul@us.ibm.com
+ */
+ if (cpu_has_tsc) {
+ unsigned long tsc_quotient = calibrate_tsc();
+ if (tsc_quotient) {
+ fast_gettimeoffset_quotient = tsc_quotient;
+ /* report CPU clock rate in Hz.
+ * The formula is (10^6 * 2^32) / (2^32 * 1 / (clocks/us)) =
+ * clock/second. Our precision is about 100 ppm.
+ */
+ { unsigned long eax=0, edx=1000;
+ __asm__("divl %2"
+ :"=a" (cpu_khz), "=d" (edx)
+ :"r" (tsc_quotient),
+ "0" (eax), "1" (edx));
+ printk("Detected %lu.%03lu MHz processor.\n", cpu_khz / 1000, cpu_khz % 1000);
+ }
}
}

diff -Nru a/arch/i386/kernel/timers/timer_tsc.c b/arch/i386/kernel/timers/timer_tsc.c
--- a/arch/i386/kernel/timers/timer_tsc.c Wed Jan 22 13:35:09 2003
+++ b/arch/i386/kernel/timers/timer_tsc.c Wed Jan 22 13:35:09 2003
@@ -130,7 +130,7 @@
#define CALIBRATE_LATCH (5 * LATCH)
#define CALIBRATE_TIME (5 * 1000020/HZ)

-static unsigned long __init calibrate_tsc(void)
+unsigned long __init calibrate_tsc(void)
{
/* Set the Gate high, disable speaker */
outb((inb(0x61) & ~0x02) | 0x01, 0x61);


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