1 | // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 |
2 | /****************************************************************************** |
3 | * |
4 | * Name: hwtimer.c - ACPI Power Management Timer Interface |
5 | * |
6 | * Copyright (C) 2000 - 2023, Intel Corp. |
7 | * |
8 | *****************************************************************************/ |
9 | |
10 | #define EXPORT_ACPI_INTERFACES |
11 | |
12 | #include <acpi/acpi.h> |
13 | #include "accommon.h" |
14 | |
15 | #define _COMPONENT ACPI_HARDWARE |
16 | ACPI_MODULE_NAME("hwtimer" ) |
17 | |
18 | #if (!ACPI_REDUCED_HARDWARE) /* Entire module */ |
19 | /****************************************************************************** |
20 | * |
21 | * FUNCTION: acpi_get_timer_resolution |
22 | * |
23 | * PARAMETERS: resolution - Where the resolution is returned |
24 | * |
25 | * RETURN: Status and timer resolution |
26 | * |
27 | * DESCRIPTION: Obtains resolution of the ACPI PM Timer (24 or 32 bits). |
28 | * |
29 | ******************************************************************************/ |
30 | acpi_status acpi_get_timer_resolution(u32 * resolution) |
31 | { |
32 | ACPI_FUNCTION_TRACE(acpi_get_timer_resolution); |
33 | |
34 | if (!resolution) { |
35 | return_ACPI_STATUS(AE_BAD_PARAMETER); |
36 | } |
37 | |
38 | if ((acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER) == 0) { |
39 | *resolution = 24; |
40 | } else { |
41 | *resolution = 32; |
42 | } |
43 | |
44 | return_ACPI_STATUS(AE_OK); |
45 | } |
46 | |
47 | ACPI_EXPORT_SYMBOL(acpi_get_timer_resolution) |
48 | |
49 | /****************************************************************************** |
50 | * |
51 | * FUNCTION: acpi_get_timer |
52 | * |
53 | * PARAMETERS: ticks - Where the timer value is returned |
54 | * |
55 | * RETURN: Status and current timer value (ticks) |
56 | * |
57 | * DESCRIPTION: Obtains current value of ACPI PM Timer (in ticks). |
58 | * |
59 | ******************************************************************************/ |
60 | acpi_status acpi_get_timer(u32 * ticks) |
61 | { |
62 | acpi_status status; |
63 | u64 timer_value; |
64 | |
65 | ACPI_FUNCTION_TRACE(acpi_get_timer); |
66 | |
67 | if (!ticks) { |
68 | return_ACPI_STATUS(AE_BAD_PARAMETER); |
69 | } |
70 | |
71 | /* ACPI 5.0A: PM Timer is optional */ |
72 | |
73 | if (!acpi_gbl_FADT.xpm_timer_block.address) { |
74 | return_ACPI_STATUS(AE_SUPPORT); |
75 | } |
76 | |
77 | status = acpi_hw_read(&timer_value, &acpi_gbl_FADT.xpm_timer_block); |
78 | if (ACPI_SUCCESS(status)) { |
79 | |
80 | /* ACPI PM Timer is defined to be 32 bits (PM_TMR_LEN) */ |
81 | |
82 | *ticks = (u32)timer_value; |
83 | } |
84 | |
85 | return_ACPI_STATUS(status); |
86 | } |
87 | |
88 | ACPI_EXPORT_SYMBOL(acpi_get_timer) |
89 | |
90 | /****************************************************************************** |
91 | * |
92 | * FUNCTION: acpi_get_timer_duration |
93 | * |
94 | * PARAMETERS: start_ticks - Starting timestamp |
95 | * end_ticks - End timestamp |
96 | * time_elapsed - Where the elapsed time is returned |
97 | * |
98 | * RETURN: Status and time_elapsed |
99 | * |
100 | * DESCRIPTION: Computes the time elapsed (in microseconds) between two |
101 | * PM Timer time stamps, taking into account the possibility of |
102 | * rollovers, the timer resolution, and timer frequency. |
103 | * |
104 | * The PM Timer's clock ticks at roughly 3.6 times per |
105 | * _microsecond_, and its clock continues through Cx state |
106 | * transitions (unlike many CPU timestamp counters) -- making it |
107 | * a versatile and accurate timer. |
108 | * |
109 | * Note that this function accommodates only a single timer |
110 | * rollover. Thus for 24-bit timers, this function should only |
111 | * be used for calculating durations less than ~4.6 seconds |
112 | * (~20 minutes for 32-bit timers) -- calculations below: |
113 | * |
114 | * 2**24 Ticks / 3,600,000 Ticks/Sec = 4.66 sec |
115 | * 2**32 Ticks / 3,600,000 Ticks/Sec = 1193 sec or 19.88 minutes |
116 | * |
117 | ******************************************************************************/ |
118 | acpi_status |
119 | acpi_get_timer_duration(u32 start_ticks, u32 end_ticks, u32 *time_elapsed) |
120 | { |
121 | acpi_status status; |
122 | u64 delta_ticks; |
123 | u64 quotient; |
124 | |
125 | ACPI_FUNCTION_TRACE(acpi_get_timer_duration); |
126 | |
127 | if (!time_elapsed) { |
128 | return_ACPI_STATUS(AE_BAD_PARAMETER); |
129 | } |
130 | |
131 | /* ACPI 5.0A: PM Timer is optional */ |
132 | |
133 | if (!acpi_gbl_FADT.xpm_timer_block.address) { |
134 | return_ACPI_STATUS(AE_SUPPORT); |
135 | } |
136 | |
137 | if (start_ticks == end_ticks) { |
138 | *time_elapsed = 0; |
139 | return_ACPI_STATUS(AE_OK); |
140 | } |
141 | |
142 | /* |
143 | * Compute Tick Delta: |
144 | * Handle (max one) timer rollovers on 24-bit versus 32-bit timers. |
145 | */ |
146 | delta_ticks = end_ticks; |
147 | if (start_ticks > end_ticks) { |
148 | if ((acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER) == 0) { |
149 | |
150 | /* 24-bit Timer */ |
151 | |
152 | delta_ticks |= (u64)1 << 24; |
153 | } else { |
154 | /* 32-bit Timer */ |
155 | |
156 | delta_ticks |= (u64)1 << 32; |
157 | } |
158 | } |
159 | delta_ticks -= start_ticks; |
160 | |
161 | /* |
162 | * Compute Duration (Requires a 64-bit multiply and divide): |
163 | * |
164 | * time_elapsed (microseconds) = |
165 | * (delta_ticks * ACPI_USEC_PER_SEC) / ACPI_PM_TIMER_FREQUENCY; |
166 | */ |
167 | status = acpi_ut_short_divide(delta_ticks * ACPI_USEC_PER_SEC, |
168 | ACPI_PM_TIMER_FREQUENCY, "ient, NULL); |
169 | |
170 | *time_elapsed = (u32)quotient; |
171 | return_ACPI_STATUS(status); |
172 | } |
173 | |
174 | ACPI_EXPORT_SYMBOL(acpi_get_timer_duration) |
175 | #endif /* !ACPI_REDUCED_HARDWARE */ |
176 | |