| 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 | |