Upintegrate the common_time service from ics-aah.
Move the common_time service developed in the ics-aah branch back into
master.
The common_time service is a small service build to synchronize an
arbitrary timeline amongst peers on a local sub-net. While running
and configured, the service will elect a master from the set of
available devices within the subnet, define a relationship between the
common_time timeline the local time timeline (provided by the local
time HAL), and then attempt to maintain synchronization between common
and local time by controlling the frequency of the local time clock
via the HAL, or by disciplining local time in the digital domain if
the local time HAL implementation does not support HW slewing.
On its own, the native common time service will do nothing until it is
configured. The CommonTimeManagementService (running out of the
system server process) is responsible for implementing policy
regarding configuration and operation of the common_time service and
will be added in a subsequent CL.
Change-Id: I71292f9b9b1797665865689c4572c9d3a0552f64
Signed-off-by: John Grossman <johngro@google.com>
diff --git a/services/common_time/clock_recovery.h b/services/common_time/clock_recovery.h
new file mode 100644
index 0000000..5c35c38
--- /dev/null
+++ b/services/common_time/clock_recovery.h
@@ -0,0 +1,123 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef __CLOCK_RECOVERY_H__
+#define __CLOCK_RECOVERY_H__
+
+#include <stdint.h>
+#include <common_time/ICommonClock.h>
+#include <utils/LinearTransform.h>
+#include <utils/threads.h>
+
+#ifdef TIME_SERVICE_DEBUG
+#include "diag_thread.h"
+#endif
+
+namespace android {
+
+class CommonClock;
+class LocalClock;
+
+class ClockRecoveryLoop {
+ public:
+ ClockRecoveryLoop(LocalClock* local_clock, CommonClock* common_clock);
+ ~ClockRecoveryLoop();
+
+ void reset(bool position, bool frequency);
+ bool pushDisciplineEvent(int64_t local_time,
+ int64_t nominal_common_time,
+ int64_t data_point_rtt);
+ int32_t getLastErrorEstimate();
+
+ private:
+ typedef struct {
+ // Limits for the correction factor supplied to set_counter_slew_rate.
+ // The controller will always clamp its output to the range expressed by
+ // correction_(min|max)
+ int32_t correction_min;
+ int32_t correction_max;
+
+ // Limits for the internal integration accumulator in the PID
+ // controller. The value of the accumulator is scaled by gain_I to
+ // produce the integral component of the PID controller output.
+ // Platforms can use these limits to prevent windup in the system
+ // if/when the correction factor needs to be driven to saturation for
+ // extended periods of time.
+ int32_t integrated_delta_min;
+ int32_t integrated_delta_max;
+
+ // Gain for the P, I and D components of the controller.
+ LinearTransform gain_P;
+ LinearTransform gain_I;
+ LinearTransform gain_D;
+ } PIDParams;
+
+ typedef struct {
+ int64_t local_time;
+ int64_t observed_common_time;
+ int64_t nominal_common_time;
+ int64_t rtt;
+ bool point_used;
+ } DisciplineDataPoint;
+
+ static uint32_t findMinRTTNdx(DisciplineDataPoint* data, uint32_t count);
+
+ void computePIDParams();
+ void reset_l(bool position, bool frequency);
+ static int32_t doGainScale(const LinearTransform& gain, int32_t val);
+ void applySlew();
+
+ // The local clock HW abstraction we use as the basis for common time.
+ LocalClock* local_clock_;
+ bool local_clock_can_slew_;
+
+ // The common clock we end up controlling along with the lock used to
+ // serialize operations.
+ CommonClock* common_clock_;
+ Mutex lock_;
+
+ // The parameters computed to be used for the PID Controller.
+ PIDParams pid_params_;
+
+ // The maximum allowed error (as indicated by a pushDisciplineEvent) before
+ // we panic.
+ int32_t panic_thresh_;
+
+ // parameters maintained while running and reset during a reset
+ // of the frequency correction.
+ bool last_delta_valid_;
+ int32_t last_delta_;
+ int32_t integrated_error_;
+ int32_t correction_cur_;
+
+ // State kept for filtering the discipline data.
+ static const uint32_t kFilterSize = 6;
+ DisciplineDataPoint filter_data_[kFilterSize];
+ uint32_t filter_wr_;
+ bool filter_full_;
+
+ static const uint32_t kStartupFilterSize = 4;
+ DisciplineDataPoint startup_filter_data_[kStartupFilterSize];
+ uint32_t startup_filter_wr_;
+
+#ifdef TIME_SERVICE_DEBUG
+ sp<DiagThread> diag_thread_;
+#endif
+};
+
+} // namespace android
+
+#endif // __CLOCK_RECOVERY_H__