osfmk/i386/rtclock_native.c

   1 /*
   2  * Copyright (c) 2000-2010 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 #include <platforms.h>
  33 #include <mach_kdb.h>
  34
  35 #include <mach/mach_types.h>
  36
  37 #include <architecture/i386/pio.h>
  38 #include <i386/machine_cpu.h>
  39 #include <i386/cpuid.h>
  40 #include <i386/cpu_threads.h>
  41 #include <i386/mp.h>
  42 #include <i386/machine_routines.h>
  43 #include <i386/pal_routines.h>
  44 #include <i386/proc_reg.h>
  45 #include <i386/misc_protos.h>
  46 #include <i386/lapic.h>
  47 #include <pexpert/pexpert.h>
  48 #include <machine/limits.h>
  49 #include <sys/kdebug.h>
  50 #include <i386/tsc.h>
  51 #include <i386/rtclock_protos.h>
  52 #include <i386/pal_routines.h>
  53 #include <kern/etimer.h>
  54
  55 static uint64_t rtc_decrementer_min;
  56 static uint64_t rtc_decrementer_max;
  57
  58 static uint64_t
  59 deadline_to_decrementer(
  60         uint64_t        deadline,
  61         uint64_t        now)
  62 {
  63         uint64_t        delta;
  64
  65         if (deadline <= now)
  66                 return rtc_decrementer_min;
  67         else {
  68                 delta = deadline - now;
  69                 return MIN(MAX(rtc_decrementer_min,delta),rtc_decrementer_max);
  70         }
  71 }
  72
  73 static inline uint64_t
  74 _absolutetime_to_tsc(uint64_t ns)
  75 {
  76         uint32_t        generation;
  77         uint64_t        tsc;
  78
  79         do {
  80                 generation =  pal_rtc_nanotime_info.generation;
  81                 tsc = tmrCvt(ns - pal_rtc_nanotime_info.ns_base, tscFCvtn2t)
  82                         + pal_rtc_nanotime_info.tsc_base;
  83         } while (generation == 0 ||
  84                  generation != pal_rtc_nanotime_info.generation);
  85
  86         return tsc;
  87 }
  88
  89 /*
  90  * Regular local APIC timer case:
  91  */
  92 static void
  93 rtc_lapic_config_timer(void)
  94 {
  95         lapic_config_timer(TRUE, one_shot, divide_by_1);
  96 }
  97 static uint64_t
  98 rtc_lapic_set_timer(uint64_t deadline, uint64_t now)
  99 {
 100         uint64_t count;
 101         uint64_t set = 0;
 102
 103         if (deadline > 0) {
 104                 /*
 105                  * Convert delta to bus ticks
 106                  * - time now is not relevant
 107                  */
 108                 count = deadline_to_decrementer(deadline, now);
 109                 set = now + count;
 110                 lapic_set_timer_fast((uint32_t) tmrCvt(count, busFCvtn2t));
 111         } else {
 112                 lapic_set_timer(FALSE, one_shot, divide_by_1, 0);
 113         }
 114         return set;
 115 }
 116
 117 /*
 118  * TSC-deadline timer case:
 119  */
 120 static void
 121 rtc_lapic_config_tsc_deadline_timer(void)
 122 {
 123         lapic_config_tsc_deadline_timer();
 124 }
 125 static uint64_t
 126 rtc_lapic_set_tsc_deadline_timer(uint64_t deadline, uint64_t now)
 127 {
 128         uint64_t        set = 0;
 129
 130         if (deadline > 0) {
 131                 /*
 132                  * Convert to TSC
 133                  */
 134                 set = now + deadline_to_decrementer(deadline, now);
 135                 lapic_set_tsc_deadline_timer(_absolutetime_to_tsc(set));
 136         } else {
 137                 lapic_set_tsc_deadline_timer(0);
 138         }
 139
 140         KERNEL_DEBUG_CONSTANT(
 141                 DECR_SET_TSC_DEADLINE | DBG_FUNC_NONE,
 142                 now, deadline,
 143                 rdtsc64(), lapic_get_tsc_deadline_timer(),
 144                 0);
 145
 146         return set;
 147 }
 148
 149 /*
 150  * Definitions for timer operations table
 151  */
 152
 153 rtc_timer_t     rtc_timer_lapic  = {
 154         rtc_lapic_config_timer,
 155         rtc_lapic_set_timer
 156 };
 157
 158 rtc_timer_t     rtc_timer_tsc_deadline  = {
 159         rtc_lapic_config_tsc_deadline_timer,
 160         rtc_lapic_set_tsc_deadline_timer
 161 };
 162
 163 rtc_timer_t     *rtc_timer = &rtc_timer_lapic; /* defaults to LAPIC timer */
 164
 165 /*
 166  * rtc_timer_init() is called at startup on the boot processor only.
 167  */
 168 void
 169 rtc_timer_init(void)
 170 {
 171         int     TSC_deadline_timer = 0;
 172
 173         /* See whether we can use the local apic in TSC-deadline mode */
 174         if ((cpuid_features() & CPUID_FEATURE_TSCTMR)) {
 175                 TSC_deadline_timer = 1;
 176                 PE_parse_boot_argn("TSC_deadline_timer", &TSC_deadline_timer,
 177                                    sizeof(TSC_deadline_timer));
 178                 printf("TSC Deadline Timer supported %s enabled\n",
 179                         TSC_deadline_timer ? "and" : "but not");
 180         }
 181
 182         if (TSC_deadline_timer) {
 183                 rtc_timer = &rtc_timer_tsc_deadline;
 184                 rtc_decrementer_max = UINT64_MAX;       /* effectively none */
 185                 /*
 186                  * The min could be as low as 1nsec,
 187                  * but we're being conservative for now and making it the same
 188                  * as for the local apic timer.
 189                  */
 190                 rtc_decrementer_min = 1*NSEC_PER_USEC;  /* 1 usec */
 191         } else {
 192                 /*
 193                  * Compute the longest interval using LAPIC timer.
 194                  */
 195                 rtc_decrementer_max = tmrCvt(0x7fffffffULL, busFCvtt2n);
 196                 kprintf("maxDec: %lld\n", rtc_decrementer_max);
 197                 rtc_decrementer_min = 1*NSEC_PER_USEC;  /* 1 usec */
 198         }
 199
 200         /* Point LAPIC interrupts to hardclock() */
 201         lapic_set_timer_func((i386_intr_func_t) rtclock_intr);
 202 }