osfmk/i386/tsc.c

   1 /*
   2  * Copyright (c) 2005-2007 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*
  29  * @OSF_COPYRIGHT@
  30  */
  31
  32 /*
  33  *      File:           i386/tsc.c
  34  *      Purpose:        Initializes the TSC and the various conversion
  35  *                      factors needed by other parts of the system.
  36  */
  37
  38 #include <platforms.h>
  39 #include <mach_kdb.h>
  40
  41 #include <mach/mach_types.h>
  42
  43 #include <kern/cpu_data.h>
  44 #include <kern/cpu_number.h>
  45 #include <kern/clock.h>
  46 #include <kern/host_notify.h>
  47 #include <kern/macro_help.h>
  48 #include <kern/misc_protos.h>
  49 #include <kern/spl.h>
  50 #include <kern/assert.h>
  51 #include <mach/vm_prot.h>
  52 #include <vm/pmap.h>
  53 #include <vm/vm_kern.h>         /* for kernel_map */
  54 #include <architecture/i386/pio.h>
  55 #include <i386/machine_cpu.h>
  56 #include <i386/cpuid.h>
  57 #include <i386/mp.h>
  58 #include <i386/machine_routines.h>
  59 #include <i386/proc_reg.h>
  60 #include <i386/tsc.h>
  61 #include <i386/misc_protos.h>
  62 #include <pexpert/pexpert.h>
  63 #include <machine/limits.h>
  64 #include <machine/commpage.h>
  65 #include <sys/kdebug.h>
  66 #include <pexpert/device_tree.h>
  67
  68 uint64_t        busFCvtt2n = 0;
  69 uint64_t        busFCvtn2t = 0;
  70 uint64_t        tscFreq = 0;
  71 uint64_t        tscFCvtt2n = 0;
  72 uint64_t        tscFCvtn2t = 0;
  73 uint64_t        tscGranularity = 0;
  74 uint64_t        bus2tsc = 0;
  75 uint64_t        busFreq = 0;
  76 uint32_t        flex_ratio = 0;
  77 uint32_t        flex_ratio_min = 0;
  78 uint32_t        flex_ratio_max = 0;
  79
  80
  81 #define bit(n)          (1ULL << (n))
  82 #define bitmask(h,l)    ((bit(h)|(bit(h)-1)) & ~(bit(l)-1))
  83 #define bitfield(x,h,l) (((x) & bitmask(h,l)) >> l)
  84
  85 /* Decimal powers: */
  86 #define kilo (1000ULL)
  87 #define Mega (kilo * kilo)
  88 #define Giga (kilo * Mega)
  89 #define Tera (kilo * Giga)
  90 #define Peta (kilo * Tera)
  91
  92 #define CPU_FAMILY_PENTIUM_M    (0x6)
  93
  94 static const char       FSB_Frequency_prop[] = "FSBFrequency";
  95 /*
  96  * This routine extracts the bus frequency in Hz from the device tree.
  97  */
  98 static uint64_t
  99 EFI_FSB_frequency(void)
 100 {
 101         uint64_t        frequency = 0;
 102         DTEntry         entry;
 103         void            *value;
 104         unsigned int    size;
 105
 106         if (DTLookupEntry(0, "/efi/platform", &entry) != kSuccess) {
 107                 kprintf("EFI_FSB_frequency: didn't find /efi/platform\n");
 108                 return 0;
 109         }
 110         if (DTGetProperty(entry,FSB_Frequency_prop,&value,&size) != kSuccess) {
 111                 kprintf("EFI_FSB_frequency: property %s not found\n",
 112                         FSB_Frequency_prop);
 113                 return 0;
 114         }
 115         if (size == sizeof(uint64_t)) {
 116                 frequency = *(uint64_t *) value;
 117                 kprintf("EFI_FSB_frequency: read %s value: %llu\n",
 118                         FSB_Frequency_prop, frequency);
 119                 if (!(90*Mega < frequency && frequency < 10*Giga)) {
 120                         kprintf("EFI_FSB_frequency: value out of range\n");
 121                         frequency = 0;
 122                 }
 123         } else {
 124                 kprintf("EFI_FSB_frequency: unexpected size %d\n", size);
 125         }
 126         return frequency;
 127 }
 128
 129 /*
 130  * Initialize the various conversion factors needed by code referencing
 131  * the TSC.
 132  */
 133 void
 134 tsc_init(void)
 135 {
 136         uint64_t        busFCvtInt = 0;
 137         boolean_t       N_by_2_bus_ratio = FALSE;
 138
 139         /*
 140          * Get the FSB frequency and conversion factors from EFI.
 141          */
 142         busFreq = EFI_FSB_frequency();
 143
 144         switch (cpuid_cpufamily()) {
 145         case CPUFAMILY_INTEL_SANDYBRIDGE:
 146         case CPUFAMILY_INTEL_WESTMERE:
 147         case CPUFAMILY_INTEL_NEHALEM: {
 148                 uint64_t cpu_mhz;
 149                 uint64_t msr_flex_ratio;
 150                 uint64_t msr_platform_info;
 151
 152                 /* See if FLEX_RATIO is being used */
 153                 msr_flex_ratio = rdmsr64(MSR_FLEX_RATIO);
 154                 msr_platform_info = rdmsr64(MSR_PLATFORM_INFO);
 155                 flex_ratio_min = (uint32_t)bitfield(msr_platform_info, 47, 40);
 156                 flex_ratio_max = (uint32_t)bitfield(msr_platform_info, 15, 8);
 157                 /* No BIOS-programed flex ratio. Use hardware max as default */
 158                 tscGranularity = flex_ratio_max;
 159                 if (msr_flex_ratio & bit(16)) {
 160                         /* Flex Enabled: Use this MSR if less than max */
 161                         flex_ratio = (uint32_t)bitfield(msr_flex_ratio, 15, 8);
 162                         if (flex_ratio < flex_ratio_max)
 163                                 tscGranularity = flex_ratio;
 164                 }
 165
 166                 /* If EFI isn't configured correctly, use a constant
 167                  * value. See 6036811.
 168                  */
 169                 if (busFreq == 0)
 170                     busFreq = BASE_NHM_CLOCK_SOURCE;
 171
 172                 cpu_mhz = tscGranularity * BASE_NHM_CLOCK_SOURCE;
 173
 174                 break;
 175             }
 176         default: {
 177                 uint64_t        prfsts;
 178
 179                 prfsts = rdmsr64(IA32_PERF_STS);
 180                 tscGranularity = (uint32_t)bitfield(prfsts, 44, 40);
 181                 N_by_2_bus_ratio = (prfsts & bit(46)) != 0;
 182             }
 183         }
 184
 185         if (busFreq != 0) {
 186                 busFCvtt2n = ((1 * Giga) << 32) / busFreq;
 187                 busFCvtn2t = 0xFFFFFFFFFFFFFFFFULL / busFCvtt2n;
 188                 busFCvtInt = tmrCvt(1 * Peta, 0xFFFFFFFFFFFFFFFFULL / busFreq);
 189         } else {
 190                 panic("tsc_init: EFI not supported!\n");
 191         }
 192
 193         kprintf(" BUS: Frequency = %6d.%04dMHz, "
 194                 "cvtt2n = %08X.%08X, cvtn2t = %08X.%08X, "
 195                 "cvtInt = %08X.%08X\n",
 196                 (uint32_t)(busFreq / Mega),
 197                 (uint32_t)(busFreq % Mega),
 198                 (uint32_t)(busFCvtt2n >> 32), (uint32_t)busFCvtt2n,
 199                 (uint32_t)(busFCvtn2t >> 32), (uint32_t)busFCvtn2t,
 200                 (uint32_t)(busFCvtInt >> 32), (uint32_t)busFCvtInt);
 201
 202         /*
 203          * Get the TSC increment.  The TSC is incremented by this
 204          * on every bus tick.  Calculate the TSC conversion factors
 205          * to and from nano-seconds.
 206          * The tsc granularity is also called the "bus ratio". If the N/2 bit
 207          * is set this indicates the bus ration is 0.5 more than this - i.e.
 208          * that the true bus ratio is (2*tscGranularity + 1)/2.
 209          */
 210         if (N_by_2_bus_ratio)
 211                 tscFCvtt2n = busFCvtt2n * 2 / (1 + 2*tscGranularity);
 212         else
 213                 tscFCvtt2n = busFCvtt2n / tscGranularity;
 214
 215         tscFreq = ((1 * Giga)  << 32) / tscFCvtt2n;
 216         tscFCvtn2t = 0xFFFFFFFFFFFFFFFFULL / tscFCvtt2n;
 217
 218         kprintf(" TSC: Frequency = %6d.%04dMHz, "
 219                 "cvtt2n = %08X.%08X, cvtn2t = %08X.%08X, gran = %lld%s\n",
 220                 (uint32_t)(tscFreq / Mega),
 221                 (uint32_t)(tscFreq % Mega),
 222                 (uint32_t)(tscFCvtt2n >> 32), (uint32_t)tscFCvtt2n,
 223                 (uint32_t)(tscFCvtn2t >> 32), (uint32_t)tscFCvtn2t,
 224                 tscGranularity, N_by_2_bus_ratio ? " (N/2)" : "");
 225
 226         /*
 227          * Calculate conversion from BUS to TSC
 228          */
 229         bus2tsc = tmrCvt(busFCvtt2n, tscFCvtn2t);
 230 }
 231
 232 void
 233 tsc_get_info(tscInfo_t *info)
 234 {
 235         info->busFCvtt2n     = busFCvtt2n;
 236         info->busFCvtn2t     = busFCvtn2t;
 237         info->tscFreq        = tscFreq;
 238         info->tscFCvtt2n     = tscFCvtt2n;
 239         info->tscFCvtn2t     = tscFCvtn2t;
 240         info->tscGranularity = tscGranularity;
 241         info->bus2tsc        = bus2tsc;
 242         info->busFreq        = busFreq;
 243         info->flex_ratio     = flex_ratio;
 244         info->flex_ratio_min = flex_ratio_min;
 245         info->flex_ratio_max = flex_ratio_max;
 246 }