x86/platform: Fix Geode LX timekeeping in the generic x86 build

[pandora-kernel.git] / arch / x86 / kernel / tsc.c

diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index db48336..e8177b1 100644 (file)
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -18,6 +18,7 @@
 #include <asm/hypervisor.h>
 #include <asm/nmi.h>
 #include <asm/x86_init.h>
+#include <asm/geode.h>
 
 unsigned int __read_mostly cpu_khz;    /* TSC clocks / usec, not used here */
 EXPORT_SYMBOL(cpu_khz);
@@ -622,7 +623,8 @@ static void set_cyc2ns_scale(unsigned long cpu_khz, int cpu)
 
        if (cpu_khz) {
                *scale = (NSEC_PER_MSEC << CYC2NS_SCALE_FACTOR)/cpu_khz;
-               *offset = ns_now - (tsc_now * *scale >> CYC2NS_SCALE_FACTOR);
+               *offset = ns_now - mult_frac(tsc_now, *scale,
+                                            (1UL << CYC2NS_SCALE_FACTOR));
        }
 
        sched_clock_idle_wakeup_event(0);
@@ -801,15 +803,17 @@ EXPORT_SYMBOL_GPL(mark_tsc_unstable);
 
 static void __init check_system_tsc_reliable(void)
 {
-#ifdef CONFIG_MGEODE_LX
-       /* RTSC counts during suspend */
+#if defined(CONFIG_MGEODEGX1) || defined(CONFIG_MGEODE_LX) || defined(CONFIG_X86_GENERIC)
+       if (is_geode_lx()) {
+               /* RTSC counts during suspend */
 #define RTSC_SUSP 0x100
-       unsigned long res_low, res_high;
+               unsigned long res_low, res_high;
 
-       rdmsr_safe(MSR_GEODE_BUSCONT_CONF0, &res_low, &res_high);
-       /* Geode_LX - the OLPC CPU has a very reliable TSC */
-       if (res_low & RTSC_SUSP)
-               tsc_clocksource_reliable = 1;
+               rdmsr_safe(MSR_GEODE_BUSCONT_CONF0, &res_low, &res_high);
+               /* Geode_LX - the OLPC CPU has a very reliable TSC */
+               if (res_low & RTSC_SUSP)
+                       tsc_clocksource_reliable = 1;
+       }
 #endif
        if (boot_cpu_has(X86_FEATURE_TSC_RELIABLE))
                tsc_clocksource_reliable = 1;
@@ -934,6 +938,16 @@ static int __init init_tsc_clocksource(void)
                clocksource_tsc.rating = 0;
                clocksource_tsc.flags &= ~CLOCK_SOURCE_IS_CONTINUOUS;
        }
+
+       /*
+        * Trust the results of the earlier calibration on systems
+        * exporting a reliable TSC.
+        */
+       if (boot_cpu_has(X86_FEATURE_TSC_RELIABLE)) {
+               clocksource_register_khz(&clocksource_tsc, tsc_khz);
+               return 0;
+       }
+
        schedule_delayed_work(&tsc_irqwork, 0);
        return 0;
 }
@@ -950,14 +964,17 @@ void __init tsc_init(void)
 
        x86_init.timers.tsc_pre_init();
 
-       if (!cpu_has_tsc)
+       if (!cpu_has_tsc) {
+               setup_clear_cpu_cap(X86_FEATURE_TSC_DEADLINE_TIMER);
                return;
+       }
 
        tsc_khz = x86_platform.calibrate_tsc();
        cpu_khz = tsc_khz;
 
        if (!tsc_khz) {
                mark_tsc_unstable("could not calculate TSC khz");
+               setup_clear_cpu_cap(X86_FEATURE_TSC_DEADLINE_TIMER);
                return;
        }