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