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 <i386/ipl.h>
  55 #include <architecture/i386/pio.h>
  56 #include <i386/machine_cpu.h>
  57 #include <i386/cpuid.h>
  58 #include <i386/mp.h>
  59 #include <i386/machine_routines.h>
  60 #include <i386/proc_reg.h>
  61 #include <i386/tsc.h>
  62 #include <i386/misc_protos.h>
  63 #include <pexpert/pexpert.h>
  64 #include <machine/limits.h>
  65 #include <machine/commpage.h>
  66 #include <sys/kdebug.h>
  67 #include <pexpert/device_tree.h>
  68
  69 uint64_t        busFCvtt2n = 0;
  70 uint64_t        busFCvtn2t = 0;
  71 uint64_t        tscFreq = 0;
  72 uint64_t        tscFCvtt2n = 0;
  73 uint64_t        tscFCvtn2t = 0;
  74 uint64_t        tscGranularity = 0;
  75 uint64_t        bus2tsc = 0;
  76 uint64_t        busFreq = 0;
  77 uint32_t        flex_ratio = 0;
  78 uint32_t        flex_ratio_min = 0;
  79 uint32_t        flex_ratio_max = 0;
  80
  81
  82 #define bit(n)          (1ULL << (n))
  83 #define bitmask(h,l)    ((bit(h)|(bit(h)-1)) & ~(bit(l)-1))
  84 #define bitfield(x,h,l) (((x) & bitmask(h,l)) >> l)
  85
  86 /* Decimal powers: */
  87 #define kilo (1000ULL)
  88 #define Mega (kilo * kilo)
  89 #define Giga (kilo * Mega)
  90 #define Tera (kilo * Giga)
  91 #define Peta (kilo * Tera)
  92
  93 #define CPU_FAMILY_PENTIUM_M    (0x6)
  94
  95 static const char       FSB_Frequency_prop[] = "FSBFrequency";
  96 /*
  97  * This routine extracts the bus frequency in Hz from the device tree.
  98  */
  99 static uint64_t
 100 EFI_FSB_frequency(void)
 101 {
 102         uint64_t        frequency = 0;
 103         DTEntry         entry;
 104         void            *value;
 105         unsigned int    size;
 106
 107         if (DTLookupEntry(0, "/efi/platform", &entry) != kSuccess) {
 108                 kprintf("EFI_FSB_frequency: didn't find /efi/platform\n");
 109                 return 0;
 110         }
 111         if (DTGetProperty(entry,FSB_Frequency_prop,&value,&size) != kSuccess) {
 112                 kprintf("EFI_FSB_frequency: property %s not found\n",
 113                         FSB_Frequency_prop);
 114                 return 0;
 115         }
 116         if (size == sizeof(uint64_t)) {
 117                 frequency = *(uint64_t *) value;
 118                 kprintf("EFI_FSB_frequency: read %s value: %llu\n",
 119                         FSB_Frequency_prop, frequency);
 120                 if (!(90*Mega < frequency && frequency < 10*Giga)) {
 121                         kprintf("EFI_FSB_frequency: value out of range\n");
 122                         frequency = 0;
 123                 }
 124         } else {
 125                 kprintf("EFI_FSB_frequency: unexpected size %d\n", size);
 126         }
 127         return frequency;
 128 }
 129
 130 /*
 131  * Initialize the various conversion factors needed by code referencing
 132  * the TSC.
 133  */
 134 void
 135 tsc_init(void)
 136 {
 137         uint64_t        busFCvtInt = 0;
 138         boolean_t       N_by_2_bus_ratio = FALSE;
 139
 140         /*
 141          * Get the FSB frequency and conversion factors from EFI.
 142          */
 143         busFreq = EFI_FSB_frequency();
 144
 145         switch (cpuid_cpufamily()) {
 146         case CPUFAMILY_INTEL_NEHALEM: {
 147                 uint64_t cpu_mhz;
 148                 uint64_t msr_flex_ratio;
 149                 uint64_t msr_platform_info;
 150
 151                 /* See if FLEX_RATIO is being used */
 152                 msr_flex_ratio = rdmsr64(MSR_FLEX_RATIO);
 153                 msr_platform_info = rdmsr64(MSR_PLATFORM_INFO);
 154                 flex_ratio_min = (uint32_t)bitfield(msr_platform_info, 47, 40);
 155                 flex_ratio_max = (uint32_t)bitfield(msr_platform_info, 15, 8);
 156                 /* No BIOS-programed flex ratio. Use hardware max as default */
 157                 tscGranularity = flex_ratio_max;
 158                 if (msr_flex_ratio & bit(16)) {
 159                         /* Flex Enabled: Use this MSR if less than max */
 160                         flex_ratio = (uint32_t)bitfield(msr_flex_ratio, 15, 8);
 161                         if (flex_ratio < flex_ratio_max)
 162                                 tscGranularity = flex_ratio;
 163                 }
 164
 165                 /* If EFI isn't configured correctly, use a constant
 166                  * value. See 6036811.
 167                  */
 168                 if (busFreq == 0)
 169                     busFreq = BASE_NHM_CLOCK_SOURCE;
 170
 171                 cpu_mhz = tscGranularity * BASE_NHM_CLOCK_SOURCE;
 172
 173                 break;
 174             }
 175         default: {
 176                 uint64_t        prfsts;
 177
 178                 prfsts = rdmsr64(IA32_PERF_STS);
 179                 tscGranularity = (uint32_t)bitfield(prfsts, 44, 40);
 180                 N_by_2_bus_ratio = (prfsts & bit(46)) != 0;
 181             }
 182         }
 183
 184         if (busFreq != 0) {
 185                 busFCvtt2n = ((1 * Giga) << 32) / busFreq;
 186                 busFCvtn2t = 0xFFFFFFFFFFFFFFFFULL / busFCvtt2n;
 187                 busFCvtInt = tmrCvt(1 * Peta, 0xFFFFFFFFFFFFFFFFULL / busFreq);
 188         } else {
 189                 panic("tsc_init: EFI not supported!\n");
 190         }
 191
 192         kprintf(" BUS: Frequency = %6d.%04dMHz, "
 193                 "cvtt2n = %08X.%08X, cvtn2t = %08X.%08X, "
 194                 "cvtInt = %08X.%08X\n",
 195                 (uint32_t)(busFreq / Mega),
 196                 (uint32_t)(busFreq % Mega),
 197                 (uint32_t)(busFCvtt2n >> 32), (uint32_t)busFCvtt2n,
 198                 (uint32_t)(busFCvtn2t >> 32), (uint32_t)busFCvtn2t,
 199                 (uint32_t)(busFCvtInt >> 32), (uint32_t)busFCvtInt);
 200
 201         /*
 202          * Get the TSC increment.  The TSC is incremented by this
 203          * on every bus tick.  Calculate the TSC conversion factors
 204          * to and from nano-seconds.
 205          * The tsc granularity is also called the "bus ratio". If the N/2 bit
 206          * is set this indicates the bus ration is 0.5 more than this - i.e.
 207          * that the true bus ratio is (2*tscGranularity + 1)/2.
 208          */
 209         if (N_by_2_bus_ratio)
 210                 tscFCvtt2n = busFCvtt2n * 2 / (1 + 2*tscGranularity);
 211         else
 212                 tscFCvtt2n = busFCvtt2n / tscGranularity;
 213
 214         tscFreq = ((1 * Giga)  << 32) / tscFCvtt2n;
 215         tscFCvtn2t = 0xFFFFFFFFFFFFFFFFULL / tscFCvtt2n;
 216
 217         kprintf(" TSC: Frequency = %6d.%04dMHz, "
 218                 "cvtt2n = %08X.%08X, cvtn2t = %08X.%08X, gran = %lld%s\n",
 219                 (uint32_t)(tscFreq / Mega),
 220                 (uint32_t)(tscFreq % Mega),
 221                 (uint32_t)(tscFCvtt2n >> 32), (uint32_t)tscFCvtt2n,
 222                 (uint32_t)(tscFCvtn2t >> 32), (uint32_t)tscFCvtn2t,
 223                 tscGranularity, N_by_2_bus_ratio ? " (N/2)" : "");
 224
 225         /*
 226          * Calculate conversion from BUS to TSC
 227          */
 228         bus2tsc = tmrCvt(busFCvtt2n, tscFCvtn2t);
 229 }
 230
 231 void
 232 tsc_get_info(tscInfo_t *info)
 233 {
 234         info->busFCvtt2n     = busFCvtt2n;
 235         info->busFCvtn2t     = busFCvtn2t;
 236         info->tscFreq        = tscFreq;
 237         info->tscFCvtt2n     = tscFCvtt2n;
 238         info->tscFCvtn2t     = tscFCvtn2t;
 239         info->tscGranularity = tscGranularity;
 240         info->bus2tsc        = bus2tsc;
 241         info->busFreq        = busFreq;
 242         info->flex_ratio     = flex_ratio;
 243         info->flex_ratio_min = flex_ratio_min;
 244         info->flex_ratio_max = flex_ratio_max;
 245 }