Add a HAL representing a system-wide local time counter.

This is a squashed merge of the following changes:

commit 9def1ae65f6b4d6a8fdec147fdcd34f22f08174a
Author: John Grossman <johngro@google.com>
Date:   Fri Aug 12 11:47:20 2011 -0700

    Change the signature of set_local_slew.

    Changed the definition of the slew function in the local time HAL to take an
    int16 instead of an int32 and to use the full range of the int instead of
    attempting to imply any particular PPM range.

    Change-Id: Ia67f50e77f1fe674a63ec69460e830d1191ef5a0

commit afab51327453d1bfc7423f8ce7a28933d8fc49b2
Author: John Grossman <johngro@google.com>
Date:   Mon Jun 27 17:29:07 2011 -0700

    Remove "primary" from the local_time HAL.

    Interface instances are a pattern which should only be used by audio.  Remove
    its use from the local_time HAL.

    Change-Id: If4c458cf16a02d9dc63c04185111ae793fc57801

commit 1c26e59a66e75ccb31027f42183aaa32bde6e456
Author: John Grossman <johngro@google.com>
Date:   Fri Jun 17 14:19:24 2011 -0700

    Refactor the local/common clock services.

    This change is one of a set of 5 changes made to different repositories.  Look
    for this comment in all of them.

    Refactor the local/common clock services to match android best
    practice.  Notable changes include

    + The kernel no longer knows anything about common time.  Common time has been
      moved completely up into user land.  This has an impact on the accuracy of the
      timesync debugging code, and the netfilter assisted approach to network based
      timesync is going to have to be modified.
    + The timesync driver used by A@H is now just local time driver.
    + The kernel no longer needs access to the linear transform math code, and it
      has been removed.
    + A new HAL has been introduced to expose the concept of local time to the
      system.
    + A non-slewable stub implementation of the local time HAL based on
      CLOCK_MONOTONIC has been added.
    + The old library has been eliminated.  Its functionality has been
      distributed among the common time binder service, the local time hal and the
      linear transform utility code.
    + All clients of the old library have been changed to be clients of
      the binder service, the hal and the utility code.
    + The reset_tt utilities have been removed, they no longer have a purpose in the
      system.

    Change-Id: I39843b94f9b6d13f63b22145a2edcafe4ca87349

Change-Id: Ib264c992d564b99ef7c7847a788e4fa7f5e101b4
Signed-off-by: Mike J. Chen <mjchen@google.com>
Signed-off-by: John Grossman <johngro@google.com>

Conflicts:

	modules/Android.mk

2 files changed, 143 insertions, 0 deletions

diff --git a/modules/local_time/Android.mk b/modules/local_time/Android.mk
new file mode 100644
index 0000000..f840dc7
--- /dev/null
+++ b/modules/local_time/Android.mk
@@ -0,0 +1,34 @@
+# 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.
+
+LOCAL_PATH := $(call my-dir)
+
+# The default local time HAL module.  The default module simply uses the
+# system's clock_gettime(CLOCK_MONOTONIC) and does not support HW slewing.
+# Devices which use the default implementation should take care to ensure that
+# the oscillator backing the CLOCK_MONOTONIC implementation is phase locked to
+# the audio and video output hardware.  This default implementation is loaded
+# if no other device specific modules are present. The exact load order can be
+# seen in libhardware/hardware.c
+#
+# The format of the name is local_time.<hardware>.so
+include $(CLEAR_VARS)
+
+LOCAL_MODULE := local_time.default
+LOCAL_MODULE_PATH := $(TARGET_OUT_SHARED_LIBRARIES)/hw
+LOCAL_SRC_FILES := local_time_hw.c
+LOCAL_SHARED_LIBRARIES := liblog libcutils
+LOCAL_MODULE_TAGS := optional
+
+include $(BUILD_SHARED_LIBRARY)
diff --git a/modules/local_time/local_time_hw.c b/modules/local_time/local_time_hw.c
new file mode 100644
index 0000000..a1f5d43
--- /dev/null
+++ b/modules/local_time/local_time_hw.c
@@ -0,0 +1,109 @@
+/*
+ * 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.
+ */
+
+#define LOG_TAG "local_time_hw_default"
+//#define LOG_NDEBUG 0
+
+#include <errno.h>
+#include <stdint.h>
+#include <sys/time.h>
+#include <linux/time.h>
+
+#include <cutils/log.h>
+
+#include <hardware/hardware.h>
+#include <hardware/local_time_hal.h>
+
+struct stub_local_time_device {
+    struct local_time_hw_device device;
+};
+
+static int64_t ltdev_get_local_time(struct local_time_hw_device* dev)
+{
+    struct timespec ts;
+    uint64_t now;
+    int ret;
+
+    ret = clock_gettime(CLOCK_MONOTONIC, &ts);
+    if (ret < 0) {
+        LOGW("%s failed to fetch CLOCK_MONOTONIC value! (res = %d)",
+                dev->common.module->name, ret);
+        return 0;
+    }
+
+    now = (((uint64_t)ts.tv_sec) * 1000000000ull) +
+           ((uint64_t)ts.tv_nsec);
+
+    return (int64_t)now;
+}
+
+static uint64_t ltdev_get_local_freq(struct local_time_hw_device* dev)
+{
+    // For better or worse, linux clock_gettime routines normalize all clock
+    // frequencies to 1GHz
+    return 1000000000ull;
+}
+
+static int ltdev_close(hw_device_t *device)
+{
+    free(device);
+    return 0;
+}
+
+static int ltdev_open(const hw_module_t* module, const char* name,
+                     hw_device_t** device)
+{
+    struct stub_local_time_device *ltdev;
+    struct timespec ts;
+    int ret;
+
+    if (strcmp(name, LOCAL_TIME_HARDWARE_INTERFACE) != 0)
+        return -EINVAL;
+
+    ltdev = calloc(1, sizeof(struct stub_local_time_device));
+    if (!ltdev)
+        return -ENOMEM;
+
+    ltdev->device.common.tag = HARDWARE_DEVICE_TAG;
+    ltdev->device.common.version = 0;
+    ltdev->device.common.module = (struct hw_module_t *) module;
+    ltdev->device.common.close = ltdev_close;
+
+    ltdev->device.get_local_time = ltdev_get_local_time;
+    ltdev->device.get_local_freq = ltdev_get_local_freq;
+    ltdev->device.set_local_slew = NULL;
+    ltdev->device.get_debug_log  = NULL;
+
+    *device = &ltdev->device.common;
+
+    return 0;
+}
+
+static struct hw_module_methods_t hal_module_methods = {
+    .open = ltdev_open,
+};
+
+struct local_time_module HAL_MODULE_INFO_SYM = {
+    .common = {
+        .tag = HARDWARE_MODULE_TAG,
+        .version_major = 1,
+        .version_minor = 0,
+        .id = LOCAL_TIME_HARDWARE_MODULE_ID,
+        .name = "Default local_time HW HAL",
+        .author = "The Android Open Source Project",
+        .methods = &hal_module_methods,
+    },
+};