1 | /* $NetBSD: acpi_timer.c,v 1.22 2013/12/27 18:51:44 christos Exp $ */ |
2 | |
3 | /*- |
4 | * Copyright (c) 2006 Matthias Drochner <drochner@NetBSD.org> |
5 | * All rights reserved. |
6 | * |
7 | * Redistribution and use in source and binary forms, with or without |
8 | * modification, are permitted provided that the following conditions |
9 | * are met: |
10 | * 1. Redistributions of source code must retain the above copyright |
11 | * notice, this list of conditions and the following disclaimer. |
12 | * 2. Redistributions in binary form must reproduce the above copyright |
13 | * notice, this list of conditions and the following disclaimer in the |
14 | * documentation and/or other materials provided with the distribution. |
15 | * |
16 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
17 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
18 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
19 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
20 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
21 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
22 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
23 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
24 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
25 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
26 | * POSSIBILITY OF SUCH DAMAGE. |
27 | */ |
28 | |
29 | #include <sys/cdefs.h> |
30 | __KERNEL_RCSID(0, "$NetBSD: acpi_timer.c,v 1.22 2013/12/27 18:51:44 christos Exp $" ); |
31 | |
32 | #include <sys/types.h> |
33 | #include <sys/systm.h> |
34 | #include <sys/time.h> |
35 | #include <sys/timetc.h> |
36 | |
37 | #include <dev/acpi/acpivar.h> |
38 | #include <dev/acpi/acpi_timer.h> |
39 | |
40 | #include <machine/acpi_machdep.h> |
41 | |
42 | static int acpitimer_test(void); |
43 | |
44 | static struct timecounter acpi_timecounter = { |
45 | acpitimer_read_safe, |
46 | 0, |
47 | 0x00ffffff, |
48 | ACPI_PM_TIMER_FREQUENCY, |
49 | "ACPI-Safe" , |
50 | 900, |
51 | NULL, |
52 | NULL, |
53 | }; |
54 | |
55 | int |
56 | acpitimer_init(struct acpi_softc *sc) |
57 | { |
58 | ACPI_STATUS rv; |
59 | uint32_t bits; |
60 | int i, j; |
61 | |
62 | rv = AcpiGetTimerResolution(&bits); |
63 | |
64 | if (ACPI_FAILURE(rv)) |
65 | return -1; |
66 | |
67 | if (bits == 32) |
68 | acpi_timecounter.tc_counter_mask = 0xffffffff; |
69 | |
70 | for (i = j = 0; i < 10; i++) |
71 | j += acpitimer_test(); |
72 | |
73 | if (j >= 10) { |
74 | acpi_timecounter.tc_name = "ACPI-Fast" ; |
75 | acpi_timecounter.tc_get_timecount = acpitimer_read_fast; |
76 | acpi_timecounter.tc_quality = 1000; |
77 | } |
78 | |
79 | tc_init(&acpi_timecounter); |
80 | |
81 | aprint_debug_dev(sc->sc_dev, "%s %d-bit timer\n" , |
82 | acpi_timecounter.tc_name, bits); |
83 | |
84 | return 0; |
85 | } |
86 | |
87 | int |
88 | acpitimer_detach(void) |
89 | { |
90 | |
91 | return tc_detach(&acpi_timecounter); |
92 | } |
93 | |
94 | u_int |
95 | acpitimer_read_fast(struct timecounter *tc) |
96 | { |
97 | uint32_t t; |
98 | |
99 | (void)AcpiGetTimer(&t); |
100 | |
101 | return t; |
102 | } |
103 | |
104 | /* |
105 | * Some chipsets (PIIX4 variants) do not latch correctly; |
106 | * there is a chance that a transition is hit. |
107 | */ |
108 | u_int |
109 | acpitimer_read_safe(struct timecounter *tc) |
110 | { |
111 | uint32_t t1, t2, t3; |
112 | |
113 | (void)AcpiGetTimer(&t2); |
114 | (void)AcpiGetTimer(&t3); |
115 | |
116 | do { |
117 | t1 = t2; |
118 | t2 = t3; |
119 | |
120 | (void)AcpiGetTimer(&t3); |
121 | |
122 | } while ((t1 > t2) || (t2 > t3)); |
123 | |
124 | return t2; |
125 | } |
126 | |
127 | uint32_t |
128 | acpitimer_delta(uint32_t end, uint32_t start) |
129 | { |
130 | const u_int mask = acpi_timecounter.tc_counter_mask; |
131 | uint32_t delta; |
132 | |
133 | if (end >= start) |
134 | delta = end - start; |
135 | else |
136 | delta = ((mask - start) + end + 1) & mask; |
137 | |
138 | return delta; |
139 | } |
140 | |
141 | #define N 2000 |
142 | |
143 | static int |
144 | acpitimer_test(void) |
145 | { |
146 | uint32_t last, this, delta; |
147 | int minl, maxl, n; |
148 | |
149 | minl = 10000000; |
150 | maxl = 0; |
151 | |
152 | acpi_md_OsDisableInterrupt(); |
153 | |
154 | (void)AcpiGetTimer(&last); |
155 | |
156 | for (n = 0; n < N; n++) { |
157 | |
158 | (void)AcpiGetTimer(&this); |
159 | |
160 | delta = acpitimer_delta(this, last); |
161 | |
162 | if (delta > maxl) |
163 | maxl = delta; |
164 | else if (delta < minl) |
165 | minl = delta; |
166 | |
167 | last = this; |
168 | } |
169 | |
170 | acpi_md_OsEnableInterrupt(); |
171 | |
172 | if (maxl - minl > 2 ) |
173 | n = 0; |
174 | else if (minl < 0 || maxl == 0) |
175 | n = 0; |
176 | else |
177 | n = 1; |
178 | |
179 | return n; |
180 | } |
181 | |