xnu-1456.1.26.tar.gz

[apple/xnu.git] / osfmk / i386 / tsc.c

diff --git a/osfmk/i386/tsc.c b/osfmk/i386/tsc.c
index 624e5d431197bb8f781eabb4d074a7a056e6f613..6744a9097582329859e7f47e4b74143425c30117 100644 (file)
--- a/osfmk/i386/tsc.c
+++ b/osfmk/i386/tsc.c
@@ -53,19 +53,18 @@
 #include <vm/vm_kern.h>                /* for kernel_map */
 #include <i386/ipl.h>
 #include <architecture/i386/pio.h>
-#include <i386/misc_protos.h>
-#include <i386/proc_reg.h>
 #include <i386/machine_cpu.h>
-#include <i386/mp.h>
-#include <i386/cpu_data.h>
 #include <i386/cpuid.h>
+#include <i386/mp.h>
 #include <i386/machine_routines.h>
+#include <i386/proc_reg.h>
+#include <i386/tsc.h>
+#include <i386/misc_protos.h>
 #include <pexpert/pexpert.h>
 #include <machine/limits.h>
 #include <machine/commpage.h>
 #include <sys/kdebug.h>
 #include <pexpert/device_tree.h>
-#include <i386/tsc.h>
 
 uint64_t       busFCvtt2n = 0;
 uint64_t       busFCvtn2t = 0;
@@ -148,12 +147,43 @@ tsc_init(void)
                        cpuid_info()->cpuid_family);
        }
 
-       {
+       switch (cpuid_info()->cpuid_model) {
+       case CPUID_MODEL_NEHALEM: {
+               uint64_t cpu_mhz;
+               uint64_t msr_flex_ratio;
+               uint64_t msr_platform_info;
+
+               /* See if FLEX_RATIO is being used */
+               msr_flex_ratio = rdmsr64(MSR_FLEX_RATIO);
+               msr_platform_info = rdmsr64(MSR_PLATFORM_INFO);
+               flex_ratio_min = (uint32_t)bitfield(msr_platform_info, 47, 40);
+               flex_ratio_max = (uint32_t)bitfield(msr_platform_info, 15, 8);
+               /* No BIOS-programed flex ratio. Use hardware max as default */
+               tscGranularity = flex_ratio_max;
+               if (msr_flex_ratio & bit(16)) {
+                       /* Flex Enabled: Use this MSR if less than max */
+                       flex_ratio = (uint32_t)bitfield(msr_flex_ratio, 15, 8);
+                       if (flex_ratio < flex_ratio_max)
+                               tscGranularity = flex_ratio;
+               }
+
+               /* If EFI isn't configured correctly, use a constant 
+                * value. See 6036811.
+                */
+               if (busFreq == 0)
+                   busFreq = BASE_NHM_CLOCK_SOURCE;
+
+               cpu_mhz = tscGranularity * BASE_NHM_CLOCK_SOURCE;
+
+               break;
+            }
+       default: {
                uint64_t        prfsts;
 
                prfsts = rdmsr64(IA32_PERF_STS);
                tscGranularity = (uint32_t)bitfield(prfsts, 44, 40);
                N_by_2_bus_ratio = (prfsts & bit(46)) != 0;
+           }
        }
 
        if (busFreq != 0) {