1 /*
2  * Copyright (C) 2012 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #define __STDC_LIMIT_MACROS
18 
19 #define LOG_TAG "common_time"
20 #include <utils/Log.h>
21 
22 #include <inttypes.h>
23 #include <stdint.h>
24 
25 #include <utils/Errors.h>
26 #include <utils/LinearTransform.h>
27 
28 #include "common_clock.h"
29 
30 namespace android {
31 
CommonClock()32 CommonClock::CommonClock() {
33     cur_slew_        = 0;
34     cur_trans_valid_ = false;
35 
36     cur_trans_.a_zero = 0;
37     cur_trans_.b_zero = 0;
38     cur_trans_.a_to_b_numer = local_to_common_freq_numer_ = 1;
39     cur_trans_.a_to_b_denom = local_to_common_freq_denom_ = 1;
40     duration_trans_ = cur_trans_;
41 }
42 
init(uint64_t local_freq)43 bool CommonClock::init(uint64_t local_freq) {
44     Mutex::Autolock lock(&lock_);
45 
46     if (!local_freq)
47         return false;
48 
49     uint64_t numer = kCommonFreq;
50     uint64_t denom = local_freq;
51 
52     LinearTransform::reduce(&numer, &denom);
53     if ((numer > UINT32_MAX) || (denom > UINT32_MAX)) {
54         ALOGE("Overflow in CommonClock::init while trying to reduce %" PRIu64 "/%" PRIu64,
55              kCommonFreq, local_freq);
56         return false;
57     }
58 
59     cur_trans_.a_to_b_numer = local_to_common_freq_numer_ =
60         static_cast<uint32_t>(numer);
61     cur_trans_.a_to_b_denom = local_to_common_freq_denom_ =
62         static_cast<uint32_t>(denom);
63     duration_trans_ = cur_trans_;
64 
65     return true;
66 }
67 
localToCommon(int64_t local,int64_t * common_out) const68 status_t CommonClock::localToCommon(int64_t local, int64_t *common_out) const {
69     Mutex::Autolock lock(&lock_);
70 
71     if (!cur_trans_valid_)
72         return INVALID_OPERATION;
73 
74     if (!cur_trans_.doForwardTransform(local, common_out))
75         return INVALID_OPERATION;
76 
77     return OK;
78 }
79 
commonToLocal(int64_t common,int64_t * local_out) const80 status_t CommonClock::commonToLocal(int64_t common, int64_t *local_out) const {
81     Mutex::Autolock lock(&lock_);
82 
83     if (!cur_trans_valid_)
84         return INVALID_OPERATION;
85 
86     if (!cur_trans_.doReverseTransform(common, local_out))
87         return INVALID_OPERATION;
88 
89     return OK;
90 }
91 
localDurationToCommonDuration(int64_t localDur) const92 int64_t CommonClock::localDurationToCommonDuration(int64_t localDur) const {
93     int64_t ret;
94     duration_trans_.doForwardTransform(localDur, &ret);
95     return ret;
96 }
97 
setBasis(int64_t local,int64_t common)98 void CommonClock::setBasis(int64_t local, int64_t common) {
99     Mutex::Autolock lock(&lock_);
100 
101     cur_trans_.a_zero = local;
102     cur_trans_.b_zero = common;
103     cur_trans_valid_ = true;
104 }
105 
resetBasis()106 void CommonClock::resetBasis() {
107     Mutex::Autolock lock(&lock_);
108 
109     cur_trans_.a_zero = 0;
110     cur_trans_.b_zero = 0;
111     cur_trans_valid_ = false;
112 }
113 
setSlew(int64_t change_time,int32_t ppm)114 status_t CommonClock::setSlew(int64_t change_time, int32_t ppm) {
115     Mutex::Autolock lock(&lock_);
116 
117     int64_t new_local_basis;
118     int64_t new_common_basis;
119 
120     if (cur_trans_valid_) {
121         new_local_basis = change_time;
122         if (!cur_trans_.doForwardTransform(change_time, &new_common_basis)) {
123             ALOGE("Overflow when attempting to set slew rate to %d", ppm);
124             return INVALID_OPERATION;
125         }
126     } else {
127         new_local_basis = 0;
128         new_common_basis = 0;
129     }
130 
131     cur_slew_ = ppm;
132     uint32_t n1 = local_to_common_freq_numer_;
133     uint32_t n2 = 1000000 + cur_slew_;
134 
135     uint32_t d1 = local_to_common_freq_denom_;
136     uint32_t d2 = 1000000;
137 
138     // n1/d1 has already been reduced, no need to do so here.
139     LinearTransform::reduce(&n1, &d2);
140     LinearTransform::reduce(&n2, &d1);
141     LinearTransform::reduce(&n2, &d2);
142 
143     cur_trans_.a_zero = new_local_basis;
144     cur_trans_.b_zero = new_common_basis;
145     cur_trans_.a_to_b_numer = n1 * n2;
146     cur_trans_.a_to_b_denom = d1 * d2;
147 
148     return OK;
149 }
150 
151 }  // namespace android
152