osfmk/i386/rtclock_native.c

   1 /*
   2  * Copyright (c) 2000-2011 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
  34 #include <mach/mach_types.h>
  35
  36 #include <architecture/i386/pio.h>
  37 #include <i386/machine_cpu.h>
  38 #include <i386/cpuid.h>
  39 #include <i386/cpu_threads.h>
  40 #include <i386/mp.h>
  41 #include <i386/machine_routines.h>
  42 #include <i386/pal_routines.h>
  43 #include <i386/proc_reg.h>
  44 #include <i386/misc_protos.h>
  45 #include <i386/lapic.h>
  46 #include <pexpert/pexpert.h>
  47 #include <machine/limits.h>
  48 #include <sys/kdebug.h>
  49 #include <i386/tsc.h>
  50 #include <i386/rtclock_protos.h>
  51 #include <i386/pal_routines.h>
  52 #include <kern/timer_queue.h>
  53
  54 static uint64_t rtc_decrementer_min;
  55 static uint64_t rtc_decrementer_max;
  56
  57 static uint64_t
  58 deadline_to_decrementer(
  59         uint64_t        deadline,
  60         uint64_t        now)
  61 {
  62         uint64_t        delta;
  63
  64         if (deadline <= now)
  65                 return rtc_decrementer_min;
  66         else {
  67                 delta = deadline - now;
  68                 return MIN(MAX(rtc_decrementer_min,delta),rtc_decrementer_max);
  69         }
  70 }
  71
  72
  73 /*
  74  * Regular local APIC timer case:
  75  */
  76 static void
  77 rtc_lapic_config_timer(void)
  78 {
  79         lapic_config_timer(TRUE, one_shot, divide_by_1);
  80 }
  81 static uint64_t
  82 rtc_lapic_set_timer(uint64_t deadline, uint64_t now)
  83 {
  84         uint64_t count;
  85         uint64_t set = 0;
  86
  87         if (deadline > 0) {
  88                 /*
  89                  * Convert delta to bus ticks
  90                  * - time now is not relevant
  91                  */
  92                 count = deadline_to_decrementer(deadline, now);
  93                 set = now + count;
  94                 lapic_set_timer_fast((uint32_t) tmrCvt(count, busFCvtn2t));
  95         } else {
  96                 lapic_set_timer(FALSE, one_shot, divide_by_1, 0);
  97         }
  98         return set;
  99 }
 100
 101 /*
 102  * TSC-deadline timer case:
 103  */
 104 static void
 105 rtc_lapic_config_tsc_deadline_timer(void)
 106 {
 107         lapic_config_tsc_deadline_timer();
 108 }
 109 static uint64_t
 110 rtc_lapic_set_tsc_deadline_timer(uint64_t deadline, uint64_t now)
 111 {
 112         uint64_t delta;
 113         uint64_t delta_tsc;
 114         uint64_t tsc = rdtsc64();
 115         uint64_t set = 0;
 116
 117         if (deadline > 0) {
 118                 /*
 119                  * Convert to TSC
 120                  */
 121                 delta = deadline_to_decrementer(deadline, now);
 122                 set = now + delta;
 123                 delta_tsc = tmrCvt(delta, tscFCvtn2t);
 124                 lapic_set_tsc_deadline_timer(tsc + delta_tsc);
 125         } else {
 126                 lapic_set_tsc_deadline_timer(0);
 127         }
 128
 129         KERNEL_DEBUG_CONSTANT(
 130                 DECR_SET_TSC_DEADLINE | DBG_FUNC_NONE,
 131                 now, deadline,
 132                 tsc, lapic_get_tsc_deadline_timer(),
 133                 0);
 134
 135         return set;
 136 }
 137
 138 /*
 139  * Definitions for timer operations table
 140  */
 141
 142 rtc_timer_t     rtc_timer_lapic  = {
 143         rtc_lapic_config_timer,
 144         rtc_lapic_set_timer
 145 };
 146
 147 rtc_timer_t     rtc_timer_tsc_deadline  = {
 148         rtc_lapic_config_tsc_deadline_timer,
 149         rtc_lapic_set_tsc_deadline_timer
 150 };
 151
 152 rtc_timer_t     *rtc_timer = &rtc_timer_lapic; /* defaults to LAPIC timer */
 153
 154 /*
 155  * rtc_timer_init() is called at startup on the boot processor only.
 156  */
 157 void
 158 rtc_timer_init(void)
 159 {
 160         int     TSC_deadline_timer = 0;
 161
 162         /* See whether we can use the local apic in TSC-deadline mode */
 163         if ((cpuid_features() & CPUID_FEATURE_TSCTMR)) {
 164                 TSC_deadline_timer = 1;
 165                 PE_parse_boot_argn("TSC_deadline_timer", &TSC_deadline_timer,
 166                                    sizeof(TSC_deadline_timer));
 167                 printf("TSC Deadline Timer supported %s enabled\n",
 168                         TSC_deadline_timer ? "and" : "but not");
 169         }
 170
 171         if (TSC_deadline_timer) {
 172                 rtc_timer = &rtc_timer_tsc_deadline;
 173                 rtc_decrementer_max = UINT64_MAX;       /* effectively none */
 174                 /*
 175                  * The min could be as low as 1nsec,
 176                  * but we're being conservative for now and making it the same
 177                  * as for the local apic timer.
 178                  */
 179                 rtc_decrementer_min = 1*NSEC_PER_USEC;  /* 1 usec */
 180         } else {
 181                 /*
 182                  * Compute the longest interval using LAPIC timer.
 183                  */
 184                 rtc_decrementer_max = tmrCvt(0x7fffffffULL, busFCvtt2n);
 185                 kprintf("maxDec: %lld\n", rtc_decrementer_max);
 186                 rtc_decrementer_min = 1*NSEC_PER_USEC;  /* 1 usec */
 187         }
 188
 189         /* Point LAPIC interrupts to hardclock() */
 190         lapic_set_timer_func((i386_intr_func_t) rtclock_intr);
 191 }