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control.c
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control.c
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/*
// Copyright (c) 2015 Intel Corporation
//
// 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.
*/
#include <stdlib.h>
#include <ctype.h>
#include <fcntl.h>
#include <pthread.h>
#include <time.h>
#include <math.h>
#include <sys/epoll.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <utils/Log.h>
#include <hardware/sensors.h>
#include <linux/ioctl.h>
#include "control.h"
#include "enumeration.h"
#include "utils.h"
#include "transform.h"
#include "calibration.h"
#include "description.h"
#include "filtering.h"
#ifndef __NO_EVENTS__
#include <linux/iio/events.h>
#include <linux/iio/types.h>
#endif
#include <errno.h>
/* Currently active sensors count, per device */
static int poll_sensors_per_dev[MAX_DEVICES]; /* poll-mode sensors */
static int trig_sensors_per_dev[MAX_DEVICES]; /* trigger, event based */
static int device_fd[MAX_DEVICES]; /* fd on the /dev/iio:deviceX file */
static int events_fd[MAX_DEVICES]; /* fd on the /sys/bus/iio/devices/iio:deviceX/events/<event_name> file */
static int has_iio_ts[MAX_DEVICES]; /* ts channel available on this iio dev */
static int expected_dev_report_size[MAX_DEVICES]; /* expected iio scan len */
static int poll_fd; /* epoll instance covering all enabled sensors */
static int active_poll_sensors; /* Number of enabled poll-mode sensors */
static int flush_event_fd[2]; /* Pipe used for flush signaling */
/* We use pthread condition variables to get worker threads out of sleep */
static pthread_condattr_t thread_cond_attr [MAX_SENSORS];
static pthread_cond_t thread_release_cond [MAX_SENSORS];
static pthread_mutex_t thread_release_mutex [MAX_SENSORS];
#define FLUSH_REPORT_TAG 900
/*
* We associate tags to each of our poll set entries. These tags have the following values:
* - a iio device number if the fd is a iio character device fd
* - THREAD_REPORT_TAG_BASE + sensor handle if the fd is the receiving end of a pipe used by a sysfs data acquisition thread
*/
#define THREAD_REPORT_TAG_BASE 1000
/* If buffer enable fails, we may want to retry a few times before giving up */
#define ENABLE_BUFFER_RETRIES 3
#define ENABLE_BUFFER_RETRY_DELAY_MS 10
inline int is_enabled (int s)
{
return sensor[s].directly_enabled || sensor[s].ref_count;
}
static int check_state_change (int s, int enabled, int from_virtual)
{
if (enabled) {
if (sensor[s].directly_enabled)
return 0; /* We're being enabled but already were directly activated: no change. */
if (!from_virtual)
sensor[s].directly_enabled = 1; /* We're being directly enabled */
if (sensor[s].ref_count)
return 0; /* We were already indirectly enabled */
return 1; /* Do continue enabling this sensor */
}
if (!is_enabled(s))
return 0; /* We are being disabled but already were: no change */
if (from_virtual && sensor[s].directly_enabled)
return 0; /* We're indirectly disabled but the base is still active */
sensor[s].directly_enabled = 0; /* We're now directly disabled */
if (!from_virtual && sensor[s].ref_count)
return 0; /* We still have ref counts */
return 1; /* Do continue disabling this sensor */
}
static int enable_buffer (int dev_num, int enabled)
{
char sysfs_path[PATH_MAX];
int retries = ENABLE_BUFFER_RETRIES;
sprintf(sysfs_path, ENABLE_PATH, dev_num);
while (retries) {
/* Low level, non-multiplexed, enable/disable routine */
if (sysfs_write_int(sysfs_path, enabled) > 0)
return 0;
ALOGE("Failed enabling buffer on dev%d, retrying", dev_num);
usleep(ENABLE_BUFFER_RETRY_DELAY_MS*1000);
retries--;
}
ALOGE("Could not enable buffer\n");
return -EIO;
}
static int setup_trigger (int s, const char* trigger_val)
{
char sysfs_path[PATH_MAX];
int ret = -1, attempts = 5;
sprintf(sysfs_path, TRIGGER_PATH, sensor[s].dev_num);
if (trigger_val[0] != '\n')
ALOGI("Setting S%d (%s) trigger to %s\n", s, sensor[s].friendly_name, trigger_val);
while (ret == -1 && attempts) {
ret = sysfs_write_str(sysfs_path, trigger_val);
attempts--;
}
if (ret != -1)
sensor[s].selected_trigger = trigger_val;
else
ALOGE("Setting S%d (%s) trigger to %s FAILED.\n", s, sensor[s].friendly_name, trigger_val);
return ret;
}
static int enable_event(int dev_num, const char *name, int enabled)
{
char sysfs_path[PATH_MAX];
sprintf(sysfs_path, EVENTS_PATH "%s", dev_num, name);
return sysfs_write_int(sysfs_path, enabled);
}
static int enable_sensor(int dev_num, const char *tag, int enabled)
{
char sysfs_path[PATH_MAX];
sprintf(sysfs_path, SENSOR_ENABLE_PATH, dev_num, tag);
return sysfs_write_int(sysfs_path, enabled);
}
static void enable_iio_timestamp (int dev_num, int known_channels)
{
/* Check if we have a dedicated iio timestamp channel */
char spec_buf[MAX_TYPE_SPEC_LEN];
char sysfs_path[PATH_MAX];
int n;
sprintf(sysfs_path, CHANNEL_PATH "%s", dev_num, "in_timestamp_type");
n = sysfs_read_str(sysfs_path, spec_buf, sizeof(spec_buf));
if (n <= 0)
return;
if (strcmp(spec_buf, "le:s64/64>>0"))
return;
/* OK, type is int64_t as expected, in little endian representation */
sprintf(sysfs_path, CHANNEL_PATH"%s", dev_num, "in_timestamp_index");
if (sysfs_read_int(sysfs_path, &n))
return;
/* Check that the timestamp comes after the other fields we read */
if (n != known_channels)
return;
/* Try enabling that channel */
sprintf(sysfs_path, CHANNEL_PATH "%s", dev_num, "in_timestamp_en");
sysfs_write_int(sysfs_path, 1);
if (sysfs_read_int(sysfs_path, &n))
return;
if (n) {
ALOGI("Detected timestamp channel on iio device %d\n", dev_num);
has_iio_ts[dev_num] = 1;
}
}
static int decode_type_spec (const char type_buf[MAX_TYPE_SPEC_LEN], datum_info_t *type_info)
{
/* Return size in bytes for this type specification, or -1 in error */
char sign;
char endianness;
unsigned int realbits, storagebits, shift;
int tokens;
/* Valid specs: "le:u10/16>>0", "le:s16/32>>0" or "le:s32/32>>0" */
tokens = sscanf(type_buf, "%ce:%c%u/%u>>%u", &endianness, &sign, &realbits, &storagebits, &shift);
if (tokens != 5 || (endianness != 'b' && endianness != 'l') || (sign != 'u' && sign != 's') ||
realbits > storagebits || (storagebits != 16 && storagebits != 32 && storagebits != 64)) {
ALOGE("Invalid iio channel type spec: %s\n", type_buf);
return -1;
}
type_info->endianness = endianness;
type_info->sign = sign;
type_info->realbits = (short) realbits;
type_info->storagebits = (short) storagebits;
type_info->shift = (short) shift;
return storagebits / 8;
}
void build_sensor_report_maps (int dev_num)
{
/*
* Read sysfs files from a iio device's scan_element directory, and build a couple of tables from that data. These tables will tell, for
* each sensor, where to gather relevant data in a device report, i.e. the structure that we read from the /dev/iio:deviceX file in order to
* sensor report, itself being the data that we return to Android when a sensor poll completes. The mapping should be straightforward in the
* case where we have a single sensor active per iio device but, this is not the general case. In general several sensors can be handled
* through a single iio device, and the _en, _index and _type syfs entries all concur to paint a picture of what the structure of the
* device report is.
*/
int s;
int c;
int n;
int i;
int ch_index;
char* ch_spec;
char spec_buf[MAX_TYPE_SPEC_LEN];
datum_info_t* ch_info;
int size;
char sysfs_path[PATH_MAX];
int known_channels;
int offset;
int channel_size_from_index[MAX_SENSORS * MAX_CHANNELS] = { 0 };
int sensor_handle_from_index[MAX_SENSORS * MAX_CHANNELS] = { 0 };
int channel_number_from_index[MAX_SENSORS * MAX_CHANNELS] = { 0 };
known_channels = 0;
/* For each sensor that is linked to this device */
for (s=0; s<sensor_count; s++) {
if (sensor[s].dev_num != dev_num)
continue;
i = sensor[s].catalog_index;
/* Read channel details through sysfs attributes */
for (c=0; c<sensor[s].num_channels; c++) {
/* Read _type file */
sprintf(sysfs_path, CHANNEL_PATH "%s", sensor[s].dev_num, sensor_catalog[i].channel[c].type_path);
n = sysfs_read_str(sysfs_path, spec_buf, sizeof(spec_buf));
if (n == -1) {
ALOGW( "Failed to read type: %s\n", sysfs_path);
continue;
}
ch_spec = sensor[s].channel[c].type_spec;
memcpy(ch_spec, spec_buf, sizeof(spec_buf));
ch_info = &sensor[s].channel[c].type_info;
size = decode_type_spec(ch_spec, ch_info);
/* Read _index file */
sprintf(sysfs_path, CHANNEL_PATH "%s", sensor[s].dev_num, sensor_catalog[i].channel[c].index_path);
n = sysfs_read_int(sysfs_path, &ch_index);
if (n == -1) {
ALOGW( "Failed to read index: %s\n", sysfs_path);
continue;
}
if (ch_index >= MAX_SENSORS) {
ALOGE("Index out of bounds!: %s\n", sysfs_path);
continue;
}
/* Record what this index is about */
sensor_handle_from_index [ch_index] = s;
channel_number_from_index[ch_index] = c;
channel_size_from_index [ch_index] = size;
known_channels++;
}
sensor_update_max_range(s);
/* Stop sampling - if we are recovering from hal restart */
enable_buffer(dev_num, 0);
setup_trigger(s, "\n");
/* Turn on channels we're aware of */
for (c=0;c<sensor[s].num_channels; c++) {
sprintf(sysfs_path, CHANNEL_PATH "%s", sensor[s].dev_num, sensor_catalog[i].channel[c].en_path);
sysfs_write_int(sysfs_path, 1);
}
}
ALOGI("Found %d channels on iio device %d\n", known_channels, dev_num);
/*
* Now that we know which channels are defined, their sizes and their ordering, update channels offsets within device report. Note: there
* is a possibility that several sensors share the same index, with their data fields being isolated by masking and shifting as specified
* through the real bits and shift values in type attributes. This case is not currently supported. Also, the code below assumes no hole in
* the sequence of indices, so it is dependent on discovery of all sensors.
*/
offset = 0;
for (i=0; i<MAX_SENSORS * MAX_CHANNELS; i++) {
s = sensor_handle_from_index[i];
c = channel_number_from_index[i];
size = channel_size_from_index[i];
if (!size)
continue;
ALOGI("S%d C%d : offset %d, size %d, type %s\n", s, c, offset, size, sensor[s].channel[c].type_spec);
sensor[s].channel[c].offset = offset;
sensor[s].channel[c].size = size;
offset += size;
}
/* Enable the timestamp channel if there is one available */
enable_iio_timestamp(dev_num, known_channels);
/* Add padding and timestamp size if it's enabled on this iio device */
if (has_iio_ts[dev_num])
offset = (offset+7)/8*8 + sizeof(int64_t);
expected_dev_report_size[dev_num] = offset;
ALOGI("Expecting %d scan length on iio dev %d\n", offset, dev_num);
if (expected_dev_report_size[dev_num] > MAX_DEVICE_REPORT_SIZE) {
ALOGE("Unexpectedly large scan buffer on iio dev%d: %d bytes\n", dev_num, expected_dev_report_size[dev_num]);
expected_dev_report_size[dev_num] = MAX_DEVICE_REPORT_SIZE;
}
}
int adjust_counters (int s, int enabled, int from_virtual)
{
/*
* Adjust counters based on sensor enable action. Return values are:
* 0 if the operation was completed and we're all set
* 1 if we toggled the state of the sensor and there's work left
* -1 in case of an error
*/
int dev_num = sensor[s].dev_num;
if (!check_state_change(s, enabled, from_virtual))
return 0; /* The state of the sensor remains the same: we're done */
if (enabled) {
ALOGI("Enabling sensor %d (iio device %d: %s)\n", s, dev_num, sensor[s].friendly_name);
switch (sensor[s].type) {
case SENSOR_TYPE_ACCELEROMETER:
accel_cal_init(s);
break;
case SENSOR_TYPE_MAGNETIC_FIELD:
compass_read_data(s);
break;
case SENSOR_TYPE_GYROSCOPE:
gyro_cal_init(s);
break;
}
} else {
ALOGI("Disabling sensor %d (iio device %d: %s)\n", s, dev_num, sensor[s].friendly_name);
/* Sensor disabled, lower report available flag */
sensor[s].report_pending = 0;
/* Save calibration data to persistent storage */
switch (sensor[s].type) {
case SENSOR_TYPE_ACCELEROMETER:
accel_cal_store(s);
break;
case SENSOR_TYPE_MAGNETIC_FIELD:
compass_store_data(s);
break;
case SENSOR_TYPE_GYROSCOPE:
gyro_store_data(s);
break;
}
}
/* We changed the state of a sensor: adjust device ref counts */
switch(sensor[s].mode) {
case MODE_TRIGGER:
if (enabled)
trig_sensors_per_dev[dev_num]++;
else
trig_sensors_per_dev[dev_num]--;
return 1;
case MODE_POLL:
if (enabled) {
active_poll_sensors++;
poll_sensors_per_dev[dev_num]++;
return 1;
} else {
active_poll_sensors--;
poll_sensors_per_dev[dev_num]--;
return 1;
}
case MODE_EVENT:
return 1;
default:
/* Invalid sensor mode */
return -1;
}
}
static int get_field_count (int s, size_t *field_size)
{
*field_size = sizeof(float);
switch (sensor[s].type) {
case SENSOR_TYPE_ACCELEROMETER: /* m/s^2 */
case SENSOR_TYPE_MAGNETIC_FIELD: /* micro-tesla */
case SENSOR_TYPE_ORIENTATION: /* degrees */
case SENSOR_TYPE_GYROSCOPE_UNCALIBRATED:
case SENSOR_TYPE_GYROSCOPE: /* radians/s */
return 3;
case SENSOR_TYPE_INTERNAL_INTENSITY:
case SENSOR_TYPE_INTERNAL_ILLUMINANCE:
case SENSOR_TYPE_LIGHT: /* SI lux units */
case SENSOR_TYPE_AMBIENT_TEMPERATURE: /* °C */
case SENSOR_TYPE_TEMPERATURE: /* °C */
case SENSOR_TYPE_PROXIMITY: /* centimeters */
case SENSOR_TYPE_PRESSURE: /* hecto-pascal */
case SENSOR_TYPE_RELATIVE_HUMIDITY: /* percent */
case SENSOR_TYPE_STEP_DETECTOR: /* event: always 1 */
return 1;
case SENSOR_TYPE_ROTATION_VECTOR:
return 4;
case SENSOR_TYPE_STEP_COUNTER: /* number of steps */
*field_size = sizeof(uint64_t);
return 1;
default:
ALOGE("Unknown sensor type!\n");
return 0; /* Drop sample */
}
}
/*
* CTS acceptable thresholds:
* EventGapVerification.java: (th <= 1.8)
* FrequencyVerification.java: (0.9)*(expected freq) => (th <= 1.1111)
*/
#define THRESHOLD 1.10
#define MAX_DELAY 500000000 /* 500 ms */
void set_report_ts(int s, int64_t ts)
{
int64_t maxTs, period;
/*
* A bit of a hack to please a bunch of cts tests. They
* expect the timestamp to be exacly according to the set-up
* frequency but if we're simply getting the timestamp at hal level
* this may not be the case. Perhaps we'll get rid of this when
* we'll be reading the timestamp from the iio channel for all sensors
*/
if (sensor[s].report_ts && sensor[s].sampling_rate &&
REPORTING_MODE(sensor_desc[s].flags) == SENSOR_FLAG_CONTINUOUS_MODE)
{
period = (int64_t) (1000000000.0 / sensor[s].sampling_rate);
maxTs = sensor[s].report_ts + THRESHOLD * period;
/* If we're too far behind get back on track */
if (ts - maxTs >= MAX_DELAY)
maxTs = ts;
sensor[s].report_ts = (ts < maxTs ? ts : maxTs);
} else {
sensor[s].report_ts = ts;
}
}
static void* acquisition_routine (void* param)
{
/*
* Data acquisition routine run in a dedicated thread, covering a single sensor. This loop will periodically retrieve sampling data through
* sysfs, then package it as a sample and transfer it to our master poll loop through a report fd. Checks for a cancellation signal quite
* frequently, as the thread may be disposed of at any time. Note that Bionic does not provide pthread_cancel / pthread_testcancel...
*/
int s = (int) (size_t) param;
int num_fields;
sensors_event_t data = {0};
int c;
int ret;
struct timespec target_time;
int64_t timestamp, period, start, stop;
size_t field_size;
if (s < 0 || s >= sensor_count) {
ALOGE("Invalid sensor handle!\n");
return NULL;
}
ALOGI("Entering S%d (%s) data acquisition thread: rate:%g\n", s, sensor[s].friendly_name, sensor[s].sampling_rate);
if (sensor[s].sampling_rate <= 0) {
ALOGE("Invalid rate in acquisition routine for sensor %d: %g\n", s, sensor[s].sampling_rate);
return NULL;
}
/* Initialize data fields that will be shared by all sensor reports */
data.version = sizeof(sensors_event_t);
data.sensor = s;
data.type = sensor_desc[s].type;
num_fields = get_field_count(s, &field_size);
/*
* Each condition variable is associated to a mutex that has to be locked by the thread that's waiting on it. We use these condition
* variables to get the acquisition threads out of sleep quickly after the sampling rate is adjusted, or the sensor is disabled.
*/
pthread_mutex_lock(&thread_release_mutex[s]);
/* Pinpoint the moment we start sampling */
timestamp = get_timestamp_monotonic();
/* Check and honor termination requests */
while (sensor[s].thread_data_fd[1] != -1) {
start = get_timestamp_boot();
/* Read values through sysfs */
for (c=0; c<num_fields; c++) {
if (field_size == sizeof(uint64_t))
data.u64.data[c] = acquire_immediate_uint64_value(s, c);
else
data.data[c] = acquire_immediate_float_value(s, c);
/* Check and honor termination requests */
if (sensor[s].thread_data_fd[1] == -1)
goto exit;
}
stop = get_timestamp_boot();
set_report_ts(s, start/2 + stop/2);
data.timestamp = sensor[s].report_ts;
/* If the sample looks good */
if (sensor[s].ops.finalize(s, &data)) {
/* Pipe it for transmission to poll loop */
ret = write(sensor[s].thread_data_fd[1], &data, sizeof(sensors_event_t));
if (ret != sizeof(sensors_event_t))
ALOGE("S%d write failure: wrote %zd, got %d\n", s, sizeof(sensors_event_t), ret);
}
/* Check and honor termination requests */
if (sensor[s].thread_data_fd[1] == -1)
goto exit;
/* Recalculate period assuming sensor[s].sampling_rate can be changed dynamically during the thread run */
if (sensor[s].sampling_rate <= 0) {
ALOGE("Unexpected sampling rate for sensor %d: %g\n", s, sensor[s].sampling_rate);
goto exit;
}
period = (int64_t) (1000000000.0 / sensor[s].sampling_rate);
timestamp += period;
set_timestamp(&target_time, timestamp);
/* Wait until the sampling time elapses, or a rate change is signaled, or a thread exit is requested */
ret = pthread_cond_timedwait(&thread_release_cond[s], &thread_release_mutex[s], &target_time);
}
exit:
ALOGV("Acquisition thread for S%d exiting\n", s);
pthread_mutex_unlock(&thread_release_mutex[s]);
pthread_exit(0);
return NULL;
}
static void start_acquisition_thread (int s)
{
int incoming_data_fd;
int ret;
struct epoll_event ev = {0};
ALOGV("Initializing acquisition context for sensor %d\n", s);
/* Create condition variable and mutex for quick thread release */
ret = pthread_condattr_init(&thread_cond_attr[s]);
ret = pthread_condattr_setclock(&thread_cond_attr[s], CLOCK_MONOTONIC);
ret = pthread_cond_init(&thread_release_cond[s], &thread_cond_attr[s]);
ret = pthread_mutex_init(&thread_release_mutex[s], NULL);
/* Create a pipe for inter thread communication */
ret = pipe(sensor[s].thread_data_fd);
incoming_data_fd = sensor[s].thread_data_fd[0];
ev.events = EPOLLIN;
ev.data.u32 = THREAD_REPORT_TAG_BASE + s;
/* Add incoming side of pipe to our poll set, with a suitable tag */
ret = epoll_ctl(poll_fd, EPOLL_CTL_ADD, incoming_data_fd , &ev);
if (ret == -1) {
ALOGE("Failed adding %d to poll set (%s)\n",
incoming_data_fd, strerror(errno));
}
/* Create and start worker thread */
ret = pthread_create(&sensor[s].acquisition_thread, NULL, acquisition_routine, (void*) (size_t) s);
}
static void stop_acquisition_thread (int s)
{
int incoming_data_fd = sensor[s].thread_data_fd[0];
int outgoing_data_fd = sensor[s].thread_data_fd[1];
ALOGV("Tearing down acquisition context for sensor %d\n", s);
/* Delete the incoming side of the pipe from our poll set */
epoll_ctl(poll_fd, EPOLL_CTL_DEL, incoming_data_fd, NULL);
/* Mark the pipe ends as invalid ; that's a cheap exit flag */
sensor[s].thread_data_fd[0] = -1;
sensor[s].thread_data_fd[1] = -1;
/* Close both sides of our pipe */
close(incoming_data_fd);
close(outgoing_data_fd);
/* Stop acquisition thread and clean up thread handle */
pthread_cond_signal(&thread_release_cond[s]);
pthread_join(sensor[s].acquisition_thread, NULL);
/* Clean up our sensor descriptor */
sensor[s].acquisition_thread = -1;
/* Delete condition variable and mutex */
pthread_cond_destroy(&thread_release_cond[s]);
pthread_mutex_destroy(&thread_release_mutex[s]);
}
static int is_fast_accelerometer (int s)
{
/*
* Some games don't react well to accelerometers using any-motion triggers. Even very low thresholds seem to trip them, and they tend to
* request fairly high event rates. Favor continuous triggers if the sensor is an accelerometer and uses a sampling rate of at least 25.
*/
if (sensor[s].type != SENSOR_TYPE_ACCELEROMETER)
return 0;
if (sensor[s].sampling_rate < 25)
return 0;
return 1;
}
static void tentative_switch_trigger (int s)
{
/*
* Under certain situations it may be beneficial to use an alternate trigger:
*
* - for applications using the accelerometer with high sampling rates, prefer the continuous trigger over the any-motion one, to avoid
* jumps related to motion thresholds
*/
if (is_fast_accelerometer(s) && !(sensor[s].quirks & QUIRK_TERSE_DRIVER) && sensor[s].selected_trigger == sensor[s].motion_trigger_name)
setup_trigger(s, sensor[s].init_trigger_name);
}
static float get_group_max_sampling_rate (int s)
{
/* Review the sampling rates of linked sensors and return the maximum */
int i, vi;
float arbitrated_rate = 0;
if (is_enabled(s))
arbitrated_rate = sensor[s].requested_rate;
/* If any of the currently active sensors built on top of this one need a higher sampling rate, switch to this rate */
for (i = 0; i < sensor_count; i++)
for (vi = 0; vi < sensor[i].base_count; vi++)
if (sensor[i].base[vi] == s && is_enabled(i) && sensor[i].requested_rate > arbitrated_rate) /* If sensor i depends on sensor s */
arbitrated_rate = sensor[i].requested_rate;
/* If any of the currently active sensors we rely on is using a higher sampling rate, switch to this rate */
for (vi = 0; vi < sensor[s].base_count; vi++) {
i = sensor[s].base[vi];
if (is_enabled(i) && sensor[i].requested_rate > arbitrated_rate)
arbitrated_rate = sensor[i].requested_rate;
}
return arbitrated_rate;
}
extern float sensor_get_max_freq (int s);
static float select_closest_available_rate(int s, float requested_rate)
{
float sr;
int j;
float selected_rate = 0;
float max_rate_from_prop = sensor_get_max_freq(s);
if (!sensor[s].avail_freqs_count)
return requested_rate;
for (j = 0; j < sensor[s].avail_freqs_count; j++) {
sr = sensor[s].avail_freqs[j];
/* If this matches the selected rate, we're happy. Have some tolerance for rounding errors and avoid needless jumps to higher rates */
if ((fabs(requested_rate - sr) <= 0.01) && (sr <= max_rate_from_prop)) {
return sr;
}
/* Select rate if it's less than max freq */
if ((sr > selected_rate) && (sr <= max_rate_from_prop)) {
selected_rate = sr;
}
/*
* If we reached a higher value than the desired rate, adjust selected rate so it matches the first higher available one and
* stop parsing - this makes the assumption that rates are sorted by increasing value in the allowed frequencies string.
*/
if (sr > requested_rate) {
return selected_rate;
}
}
/* Check for wrong values */
if (selected_rate < 0.1) {
return requested_rate;
} else {
return selected_rate;
}
}
static int sensor_set_rate (int s, float requested_rate)
{
/* Set the rate at which a specific sensor should report events. See Android sensors.h for indication on sensor trigger modes */
char sysfs_path[PATH_MAX];
int dev_num = sensor[s].dev_num;
int i = sensor[s].catalog_index;
const char *prefix = sensor_catalog[i].tag;
int per_sensor_sampling_rate;
int per_device_sampling_rate;
int n;
float sr;
float group_max_sampling_rate;
float cur_sampling_rate; /* Currently used sampling rate */
float arb_sampling_rate; /* Granted sampling rate after arbitration */
char hrtimer_sampling_path[PATH_MAX];
char trigger_path[PATH_MAX];
ALOGV("Sampling rate %g requested on sensor %d (%s)\n", requested_rate, s, sensor[s].friendly_name);
sensor[s].requested_rate = requested_rate;
arb_sampling_rate = requested_rate;
if (arb_sampling_rate < sensor[s].min_supported_rate) {
ALOGV("Sampling rate %g too low for %s, using %g instead\n", arb_sampling_rate, sensor[s].friendly_name, sensor[s].min_supported_rate);
arb_sampling_rate = sensor[s].min_supported_rate;
}
/* If one of the linked sensors uses a higher rate, adopt it */
group_max_sampling_rate = get_group_max_sampling_rate(s);
if (arb_sampling_rate < group_max_sampling_rate) {
ALOGV("Using %s sampling rate to %g too due to dependency\n", sensor[s].friendly_name, arb_sampling_rate);
arb_sampling_rate = group_max_sampling_rate;
}
if (sensor[s].max_supported_rate && arb_sampling_rate > sensor[s].max_supported_rate) {
ALOGV("Sampling rate %g too high for %s, using %g instead\n", arb_sampling_rate, sensor[s].friendly_name, sensor[s].max_supported_rate);
arb_sampling_rate = sensor[s].max_supported_rate;
}
sensor[s].sampling_rate = arb_sampling_rate;
/* If the sensor is virtual, we're done */
if (sensor[s].is_virtual)
return 0;
/* If we're dealing with a poll-mode sensor */
if (sensor[s].mode == MODE_POLL) {
if (is_enabled(s))
pthread_cond_signal(&thread_release_cond[s]); /* Wake up thread so the new sampling rate gets used */
return 0;
}
sprintf(sysfs_path, SENSOR_SAMPLING_PATH, dev_num, prefix);
if (sysfs_read_float(sysfs_path, &cur_sampling_rate) != -1) {
per_sensor_sampling_rate = 1;
per_device_sampling_rate = 0;
} else {
per_sensor_sampling_rate = 0;
sprintf(sysfs_path, DEVICE_SAMPLING_PATH, dev_num);
if (sysfs_read_float(sysfs_path, &cur_sampling_rate) != -1)
per_device_sampling_rate = 1;
else
per_device_sampling_rate = 0;
}
if (!per_sensor_sampling_rate && !per_device_sampling_rate) {
ALOGE("No way to adjust sampling rate on sensor %d\n", s);
return -ENOSYS;
}
if (sensor[s].hrtimer_trigger_name[0] != '\0') {
snprintf(trigger_path, PATH_MAX, "%s%s%d/", IIO_DEVICES, "trigger", sensor[s].trigger_nr);
snprintf(hrtimer_sampling_path, PATH_MAX, "%s%s", trigger_path, "sampling_frequency");
/* Enforce frequency update when software trigger
* frequency and current sampling rate are different */
if (sysfs_read_float(hrtimer_sampling_path, &sr) != -1 && sr != cur_sampling_rate)
cur_sampling_rate = -1;
} else {
arb_sampling_rate = select_closest_available_rate(s, arb_sampling_rate);
}
/* Record the rate that was agreed upon with the sensor taken in isolation ; this avoid uncontrolled ripple effects between colocated sensor rates */
sensor[s].semi_arbitrated_rate = arb_sampling_rate;
/* Coordinate with others active sensors on the same device, if any */
if (per_device_sampling_rate)
for (n=0; n<sensor_count; n++)
if (n != s && sensor[n].dev_num == dev_num && sensor[n].num_channels && is_enabled(n) &&
sensor[n].semi_arbitrated_rate > arb_sampling_rate) {
ALOGV("Sampling rate shared between %s and %s, using %g instead of %g\n", sensor[s].friendly_name, sensor[n].friendly_name,
sensor[n].semi_arbitrated_rate, arb_sampling_rate);
arb_sampling_rate = sensor[n].semi_arbitrated_rate;
}
sensor[s].sampling_rate = arb_sampling_rate;
/* Update actual sampling rate field for this sensor and others which may be sharing the same sampling rate */
if (per_device_sampling_rate)
for (n=0; n<sensor_count; n++)
if (sensor[n].dev_num == dev_num && n != s && sensor[n].num_channels)
sensor[n].sampling_rate = arb_sampling_rate;
/* If the desired rate is already active we're all set */
if (arb_sampling_rate == cur_sampling_rate)
return 0;
ALOGI("Sensor %d (%s) sampling rate set to %g\n", s, sensor[s].friendly_name, arb_sampling_rate);
if (sensor[s].hrtimer_trigger_name[0] != '\0')
sysfs_write_float(hrtimer_sampling_path, ceilf(arb_sampling_rate));
if (trig_sensors_per_dev[dev_num])
enable_buffer(dev_num, 0);
if (sensor[s].hrtimer_trigger_name[0] != '\0') {
sysfs_write_float(sysfs_path, select_closest_available_rate(s, arb_sampling_rate));
} else {
sysfs_write_float(sysfs_path, arb_sampling_rate);
}
/* Check if it makes sense to use an alternate trigger */
tentative_switch_trigger(s);
if (trig_sensors_per_dev[dev_num])
enable_buffer(dev_num, 1);
return 0;
}
static void reapply_sampling_rates (int s)
{
/*
* The specified sensor was either enabled or disabled. Other sensors in the same group may have constraints related to this sensor
* sampling rate on their own sampling rate, so reevaluate them by retrying to use their requested sampling rate, rather than the one
* that ended up being used after arbitration.
*/
int i, j, base;
if (sensor[s].is_virtual) {
/* Take care of downwards dependencies */
for (i=0; i<sensor[s].base_count; i++) {
base = sensor[s].base[i];
sensor_set_rate(base, sensor[base].requested_rate);
}
return;
}
/* Upwards too */
for (i=0; i<sensor_count; i++)
for (j=0; j<sensor[i].base_count; j++)
if (sensor[i].base[j] == s) /* If sensor i depends on sensor s */
sensor_set_rate(i, sensor[i].requested_rate);
}
static int sensor_activate_virtual (int s, int enabled, int from_virtual)
{
int i, base;
sensor[s].event_count = 0;
sensor[s].meta_data_pending = 0;
if (!check_state_change(s, enabled, from_virtual))
return 0; /* The state of the sensor remains the same ; we're done */
if (enabled)
ALOGI("Enabling sensor %d (%s)\n", s, sensor[s].friendly_name);
else
ALOGI("Disabling sensor %d (%s)\n", s, sensor[s].friendly_name);
sensor[s].report_pending = 0;
for (i=0; i<sensor[s].base_count; i++) {
base = sensor[s].base[i];
sensor_activate(base, enabled, 1);
if (enabled)
sensor[base].ref_count++;
else
sensor[base].ref_count--;
}
/* Reevaluate sampling rates of linked sensors */
reapply_sampling_rates(s);
return 0;
}
int sensor_activate (int s, int enabled, int from_virtual)
{
char device_name[PATH_MAX];
struct epoll_event ev = {0};
int dev_fd, event_fd;
int ret, c, d;
int dev_num = sensor[s].dev_num;
size_t field_size;
int catalog_index = sensor[s].catalog_index;