// SPDX-License-Identifier: GPL-2.0-only
/*
* Driver for Chrome OS EC Sensor hub FIFO.
*
* Copyright 2020 Google LLC
*/
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/iio/iio.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_data/cros_ec_commands.h>
#include <linux/platform_data/cros_ec_proto.h>
#include <linux/platform_data/cros_ec_sensorhub.h>
#include <linux/platform_device.h>
#include <linux/sort.h>
#include <linux/slab.h>
#define CREATE_TRACE_POINTS
#include "cros_ec_sensorhub_trace.h"
/* Precision of fixed point for the m values from the filter */
#define M_PRECISION BIT(23)
/* Only activate the filter once we have at least this many elements. */
#define TS_HISTORY_THRESHOLD 8
/*
* If we don't have any history entries for this long, empty the filter to
* make sure there are no big discontinuities.
*/
#define TS_HISTORY_BORED_US 500000
/* To measure by how much the filter is overshooting, if it happens. */
#define FUTURE_TS_ANALYTICS_COUNT_MAX 100
static inline int
cros_sensorhub_send_sample(struct cros_ec_sensorhub *sensorhub,
struct cros_ec_sensors_ring_sample *sample)
{
cros_ec_sensorhub_push_data_cb_t cb;
int id = sample->sensor_id;
struct iio_dev *indio_dev;
if (id >= sensorhub->sensor_num)
return -EINVAL;
cb = sensorhub->push_data[id].push_data_cb;
if (!cb)
return 0;
indio_dev = sensorhub->push_data[id].indio_dev;
if (sample->flag & MOTIONSENSE_SENSOR_FLAG_FLUSH)
return 0;
return cb(indio_dev, sample->vector, sample->timestamp);
}
/**
* cros_ec_sensorhub_register_push_data() - register the callback to the hub.
*
* @sensorhub : Sensor Hub object
* @sensor_num : The sensor the caller is interested in.
* @indio_dev : The iio device to use when a sample arrives.
* @cb : The callback to call when a sample arrives.
*
* The callback cb will be used by cros_ec_sensorhub_ring to distribute events
* from the EC.
*
* Return: 0 when callback is registered.
* EINVAL is the sensor number is invalid or the slot already used.
*/
int cros_ec_sensorhub_register_push_data(struct cros_ec_sensorhub *sensorhub,
u8 sensor_num,
struct iio_dev *indio_dev,
cros_ec_sensorhub_push_data_cb_t cb)
{
if (sensor_num >= sensorhub->sensor_num)
return -EINVAL;
if (sensorhub->push_data[sensor_num].indio_dev)
return -EINVAL;
sensorhub->push_data[sensor_num].indio_dev = indio_dev;
sensorhub->push_data[sensor_num].push_data_cb = cb;
return 0;
}
EXPORT_SYMBOL_GPL(cros_ec_sensorhub_register_push_data);
void cros_ec_sensorhub_unregister_push_data(struct cros_ec_sensorhub *sensorhub,
u8 sensor_num)
{
sensorhub->push_data[sensor_num].indio_dev = NULL;
sensorhub->push_data[sensor_num].push_data_cb = NULL;
}
EXPORT_SYMBOL_GPL(cros_ec_sensorhub_unregister_push_data);
/**
* cros_ec_sensorhub_ring_fifo_enable() - Enable or disable interrupt generation
* for FIFO events.
* @sensorhub: Sensor Hub object
* @on: true when events are requested.
*
* To be called before sleeping or when no one is listening.
* Return: 0 on success, or an error when we can not communicate with the EC.
*
*/
int cros_ec_sensorhub_ring_fifo_enable(struct cros_ec_sensorhub *sensorhub,
bool on)
{
int ret, i;
mutex_lock(&sensorhub->cmd_lock);
if (sensorhub->tight_timestamps)
for (i = 0; i < sensorhub->sensor_num; i++)
sensorhub->batch_state[i].last_len = 0;
sensorhub->params->cmd = MOTIONSENSE_CMD_FIFO_INT_ENABLE;
sensorhub->params->fifo_int_enable.enable = on;
sensorhub->msg->outsize = sizeof(struct ec_params_motion_sense);
sensorhub->msg->insize = sizeof(struct ec_response_motion_sense);
ret = cros_ec_cmd_xfer_status(sensorhub->ec->ec_dev, sensorhub->msg);
mutex_unlock(&sensorhub->cmd_lock);
/* We expect to receive a payload of 4 bytes, ignore. */
if (ret > 0)
ret = 0;
return ret;
}
static void cros_ec_sensor_ring_median_swap(s64 *a, s64 *b)
{
s64 tmp = *a;
*a = *b;
*b = tmp;
}
/*
* cros_ec_sensor_ring_median: Gets median of an array of numbers
*
* It's implemented using the quickselect algorithm, which achieves an
* average time complexity of O(n) the middle element. In the worst case,
* the runtime of quickselect could regress to O(n^2). To mitigate this,
* algorithms like median-of-medians exist, which can guarantee O(n) even
* in the worst case. However, these algorithms come with a higher
* overhead and are more complex to implement, making quickselect a
* pragmatic choice for our use case.
*
* Warning: the input array gets modified!
*/
static s64 cros_ec_sensor_ring_median(s64 *array, size_t length)
{
int lo = 0;
int hi = length - 1;
while (lo <= hi) {
int mid = lo + (hi - lo) / 2;
int pivot, i;
if (array[lo] > array[mid])
cros_ec_sensor_ring_median_swap(&array[lo], &array[mid]);
if (array[lo] > array[hi])
cros_ec_sensor_ring_median_swap(&array[lo], &array[hi]);
if (array[mid] < array[hi])
cros_ec_sensor_ring_median_swap(&array[mid], &array[hi]);
pivot = array[hi];
i = lo - 1;
for (int j = lo; j < hi; j++)
if (array[j] < pivot)
cros_ec_sensor_ring_median_swap(&array[++i], &array[j]);
/* The pivot's index corresponds to i+1. */
cros_ec_sensor_ring_median_swap(&array[i + 1], &array[hi]);
if (i + 1 == length / 2)
return array[i + 1];
if (i + 1 > length / 2)
hi = i;
else
lo = i + 2;
}
/* Should never reach here. */
return -1;
}
/*
* IRQ Timestamp Filtering
*
* Lower down in cros_ec_sensor_ring_process_event(), for each sensor event
* we have to calculate it's timestamp in the AP timebase. There are 3 time
* points:
* a - EC timebase, sensor event
* b - EC timebase, IRQ
* c - AP timebase, IRQ
* a' - what we want: sensor even in AP timebase
*
* While a and b are recorded at accurate times (due to the EC real time
* nature); c is pretty untrustworthy, even though it's recorded the
* first thing in ec_irq_handler(). There is a very good chance we'll get
* added latency due to:
* other irqs
* ddrfreq
* cpuidle
*
* Normally a' = c - b + a, but if we do that naive math any jitter in c
* will get coupled in a', which we don't want. We want a function
* a' = cros_ec_sensor_ring_ts_filter(a) which will filter out outliers in c.
*
* Think of a graph of AP time(b) on the y axis vs EC time(c) on the x axis.
* The slope of the line won't be exactly 1, there will be some clock drift
* between the 2 chips for various reasons (mechanical stress, temperature,
* voltage). We need to extrapolate values for a future x, without trusting
* recent y values too much.
*
* We use a median filter for the slope, then another median filter for the
* y-intercept to calculate this function:
* dx[n] = x[n-1] - x[n]
* dy[n] = x[n-1] - x[n]
* m[n] = dy[n] / dx[n]
* median_m = median(m[n-k:n])
* error[i] = y[n-i] - median_m * x[n-i]
* median_error = median(error[:k])
* predicted_y = median_m * x + median_error
*
* Implementation differences from above:
* - Redefined y to be actually c - b, this gives us a lot more precision
* to do the math. (c-b)/b variations are more obvious than c/b variations.
* - Since we don't have floating point, any operations involving slope are
* done using fixed point math (*M_PRECISION)
* - Since x and y grow with time, we keep zeroing the graph (relative to
* the last sample), this way math involving *x[n-i] will not overflow
* - EC timestamps are kept in us, it improves the slope calculation precision
*/
/**
* cros_ec_sensor_ring_ts_filter_update() - Update filter history.
*
* @state: Filter information.
* @b: IRQ timestamp, EC timebase (us)
* @c: IRQ timestamp, AP timebase (ns)
*
* Given a new IRQ timestamp pair (EC and AP timebases), add it to the filter
* history.
*/
static void
cros_ec_sensor_ring_ts_filter_update(struct cros_ec_sensors_ts_filter_state
*state,
s64 b, s64 c)
{
s64 x, y;
s64 dx, dy;
s64 m; /* stored as *M_PRECISION */
s64 *m_history_copy = state->temp_buf;
s64 *error = state->temp_buf;
int i;
/* we trust b the most, that'll be our independent variable */
x = b;
/* y is the offset between AP and EC times, in ns */
y = c - b * 1000;
dx = (state->x_history[0] + state->x_offset) - x;
if (dx == 0)
return; /* we already have this irq in the history */
dy = (state->y_history[0] + state->y_offset) - y;
m = div64_s64(dy * M_PRECISION, dx);
/* Empty filter if we haven't seen any action in a while. */
if (-dx > TS_HISTORY_BORED_US)
state->history_len = 0;
/* Move everything over, also update offset to all absolute coords .*/
for (i = state->history_len - 1; i >= 1; i--) {
state->x_history[i] = state->x_history[i - 1] + dx;
state->y_history[i] = state->y_history[i - 1] + dy;
state->m_history[i] = state->m_history[i - 1];
/*
* Also use the same loop to copy m_history for future
* median extraction.
*/
m_history_copy[i] = state->m_history[i - 1];
}
/* Store the x and y, but remember offset is actually last sample. */
state->x_offset = x;
state->y_offset = y;
state->x_history[0] = 0;
state->y_history[0] = 0;
state->m_history[0] = m;
m_history_copy[0] = m;
if (state->history_len < CROS_EC_SENSORHUB_TS_HISTORY_SIZE)
state->history_len++;
/* Precalculate things for the filter. */
if (state->history_len > TS_HISTORY_THRESHOLD) {
state->median_m =
cros_ec_sensor_ring_median(m_history_copy,
state->history_len - 1);
/*
* Calculate y-intercepts as if m_median is the slope and
* points in the history are on the line. median_error will
* still be in the offset coordinate system.
*/
for (i = 0; i < state->history_len; i++)
error[i] = state->y_history[i] -
div_s64(state->median_m * state->x_history[i],
M_PRECISION);
state->median_error =
cros_ec_sensor_ring_median(error, state->history_len);
} else {
state->median_m = 0;
state->median_error = 0;
}
trace_cros_ec_sensorhub_filter(state, dx, dy);
}
/**
* cros_ec_sensor_ring_ts_filter() - Translate EC timebase timestamp to AP
* timebase
*
* @state: filter information.
* @x: any ec timestamp (us):
*
* cros_ec_sensor_ring_ts_filter(a) => a' event timestamp, AP timebase
* cros_ec_sensor_ring_ts_filter(b) => calculated timestamp when the EC IRQ
* should have happened on the AP, with low jitter
*
* Note: The filter will only activate once state->history_len goes
* over TS_HISTORY_THRESHOLD. Otherwise it'll just do the naive c - b + a
* transform.
*
* How to derive the formula, starting from:
* f(x) = median_m * x + median_error
* That's the calculated AP - EC offset (at the x point in time)
* Undo the coordinate system transform:
* f(x) = median_m * (x - x_offset) + median_error + y_offset
* Remember to undo the "y = c - b * 1000" modification:
* f(x) = median_m * (x - x_offset) + median_error + y_offset + x * 1000
*
* Return: timestamp in AP timebase (ns)
*/
static s64
cros_ec_sensor_ring_ts_filter(struct cros_ec_sensors_ts_filter_state *state,
s64 x)
{
return div_s64(state->median_m * (x - state->x_offset), M_PRECISION)
+ state->median_error + state->y_offset + x * 1000;
}
/*
* Since a and b were originally 32 bit values from the EC,
* they overflow relatively often, casting is not enough, so we need to
* add an offset.
*/
static void
cros_ec_sensor_ring_fix_overflow(s64 *ts,
const s64 overflow_period,
struct cros_ec_sensors_ec_overflow_state
*state)
{
s64 adjust;
*ts += state->offset;
if (abs(state->last - *ts) > (overflow_period / 2)) {
adjust = state->last > *ts ? overflow_period : -overflow_period;
state->offset += adjust;
*ts += adjust;
}
state->last = *ts;
}
static void
cros_ec_sensor_ring_check_for_past_timestamp(struct cros_ec_sensorhub
*sensorhub,
struct cros_ec_sensors_ring_sample
*sample)
{
const u8 sensor_id = sample->sensor_id;
/* If this event is earlier than one we saw before... */
if (sensorhub->batch_state[sensor_id].newest_sensor_event >
sample->timestamp)
/* mark it for spreading. */
sample->timestamp =
sensorhub->batch_state[sensor_id].last_ts;
else
sensorhub->batch_state[sensor_id].newest_sensor_event =
sample->timestamp;
}
/**
* cros_ec_sensor_ring_process_event() - Process one EC FIFO event
*
* @sensorhub: Sensor Hub object.
* @fifo_info: FIFO information from the EC (includes b point, EC timebase).
* @fifo_timestamp: EC IRQ, kernel timebase (aka c).
* @current_timestamp: calculated event timestamp, kernel timebase (aka a').
* @in: incoming FIFO event from EC (includes a point, EC timebase).
* @out: outgoing event to user space (includes a').
*
* Process one EC event, add it in the ring if necessary.
*
* Return: true if out event has been populated.
*/
static bool
cros_ec_sensor_ring_process_event(struct cros_ec_sensorhub *sensorhub,
const struct ec_response_motion_sense_fifo_info
*fifo_info,
const ktime_t fifo_timestamp,
ktime_t *current_timestamp,
struct ec_response_motion_sensor_data *in,
struct cros_ec_sensors_ring_sample *out)
{
const s64 now = cros_ec_get_time_ns();
int axis, async_flags;
/* Do not populate the filter based on asynchronous events. */
async_flags = in->flags &
(MOTIONSENSE_SENSOR_FLAG_ODR | MOTIONSENSE_SENSOR_FLAG_FLUSH);
if (in->flags & MOTIONSENSE_SENSOR_FLAG_TIMESTAMP && !async_flags) {
s64 a = in->timestamp;
s64 b = fifo_info->timestamp;
s64 c = fifo_timestamp;
cros_ec_sensor_ring_fix_overflow(&a, 1LL << 32,
&sensorhub->overflow_a);
cros_ec_sensor_ring_fix_overflow(&b, 1LL << 32,
&sensorhub->overflow_b);
if (sensorhub->tight_timestamps) {
cros_ec_sensor_ring_ts_filter_update(
&sensorhub->filter, b, c);
*current_timestamp = cros_ec_sensor_ring_ts_filter(
&sensorhub->filter, a);
} else {
s64 new_timestamp;
/*
* Disable filtering since we might add more jitter
* if b is in a random point in time.
*/
new_timestamp = c - b * 1000 + a * 1000;
/*
* The timestamp can be stale if we had to use the fifo
* info timestamp.
*/
if (new_timestamp - *current_timestamp > 0)
*current_timestamp = new_timestamp;
}
trace_cros_ec_sensorhub_timestamp(in->timestamp,
fifo_info->timestamp,
fifo_timestamp,
*current_timestamp,
now);
}
if (in->flags & MOTIONSENSE_SENSOR_FLAG_ODR) {
if (sensorhub->tight_timestamps) {
sensorhub->batch_state[in->sensor_num].last_len = 0;
sensorhub->batch_state[in->sensor_num].penul_len = 0;
}
/*
* ODR change is only useful for the sensor_ring, it does not
* convey information to clients.
*/
return false;
}
if (in->flags & MOTIONSENSE_SENSOR_FLAG_FLUSH) {
out->sensor_id = in->sensor_num;
out->timestamp = *current_timestamp;
out->flag = in->flags;
if (sensorhub->tight_timestamps)
sensorhub->batch_state[out->sensor_id].last_len = 0;
/*
* No other payload information provided with
* flush ack.
*/
return true;
}
if (in->flags & MOTIONSENSE_SENSOR_FLAG_TIMESTAMP)
/* If we just have a timestamp, skip this entry. */
return false;
/* Regular sample */
out->sensor_id = in->sensor_num;
trace_cros_ec_sensorhub_data(in->sensor_num,
fifo_info->timestamp,
fifo_timestamp,
*current_timestamp,
now);
if (*current_timestamp - now > 0) {
/*
* This fix is needed to overcome the timestamp filter putting
* events in the future.
*/
sensorhub->future_timestamp_total_ns +=
*current_timestamp - now;
if (++sensorhub->future_timestamp_count ==
FUTURE_TS_ANALYTICS_COUNT_MAX) {
s64 avg = div_s64(sensorhub->future_timestamp_total_ns,
sensorhub->future_timestamp_count);
dev_warn_ratelimited(sensorhub->dev,
"100 timestamps in the future, %lldns shaved on average\n",
avg);
sensorhub->future_timestamp_count = 0;
sensorhub->future_timestamp_total_ns = 0;
}
out->timestamp = now;
} else {
out->timestamp = *current_timestamp;
}
out->flag = in->flags;
for (axis = 0; axis < 3; axis++)
out->vector[axis] = in->data[axis];
if (sensorhub->tight_timestamps)
cros_ec_sensor_ring_check_for_past_timestamp(sensorhub, out);
return true;
}
/*
* cros_ec_sensor_ring_spread_add: Calculate proper timestamps then add to
* ringbuffer.
*
* This is the new spreading code, assumes every sample's timestamp
* precedes the sample. Run if tight_timestamps == true.
*
* Sometimes the EC receives only one interrupt (hence timestamp) for
* a batch of samples. Only the first sample will have the correct
* timestamp. So we must interpolate the other samples.
* We use the previous batch timestamp and our current batch timestamp
* as a way to calculate period, then spread the samples evenly.
*
* s0 int, 0ms
* s1 int, 10ms
* s2 int, 20ms
* 30ms point goes by, no interrupt, previous one is still asserted
* downloading s2 and s3
* s3 sample, 20ms (incorrect timestamp)
* s4 int, 40ms
*
* The batches are [(s0), (s1), (s2, s3), (s4)]. Since the 3rd batch
* has 2 samples in them, we adjust the timestamp of s3.
* s2 - s1 = 10ms, so s3 must be s2 + 10ms => 20ms. If s1 would have
* been part of a bigger batch things would have gotten a little
* more complicated.
*
* Note: we also assume another sensor sample doesn't break up a batch
* in 2 or more partitions. Example, there can't ever be a sync sensor
* in between S2 and S3. This simplifies the following code.
*/
static void
cros_ec_sensor_ring_spread_add(struct cros_ec_sensorhub *sensorhub,
unsigned long sensor_mask,
struct cros_ec_sensors_ring_sample *last_out)
{
struct cros_ec_sensors_ring_sample *batch_start, *next_batch_start;
int id;
for_each_set_bit(id, &sensor_mask, sensorhub->sensor_num) {
for (batch_start = sensorhub->ring; batch_start < last_out;
batch_start = next_batch_start) {
/*
* For each batch (where all samples have the same
* timestamp).
*/
int batch_len, sample_idx;
struct cros_ec_sensors_ring_sample *batch_end =
batch_start;
struct cros_ec_sensors_ring_sample *s;
s64 batch_timestamp = batch_start->timestamp;
s64 sample_period;
/*
* Skip over batches that start with the sensor types
* we're not looking at right now.
*/
if (batch_start->sensor_id != id) {
next_batch_start = batch_start + 1;
continue;
}
/*
* Do not start a batch
* from a flush, as it happens asynchronously to the
* regular flow of events.
*/
if (batch_start->flag & MOTIONSENSE_SENSOR_FLAG_FLUSH) {
cros_sensorhub_send_sample(sensorhub,
batch_start);
next_batch_start = batch_start + 1;
continue;
}
if (batch_start->timestamp <=
sensorhub->batch_state[id].last_ts) {
batch_timestamp =
sensorhub->batch_state[id].last_ts;
batch_len = sensorhub->batch_state[id].last_len;
sample_idx = batch_len;
sensorhub->batch_state[id].last_ts =
sensorhub->batch_state[id].penul_ts;
sensorhub->batch_state[id].last_len =
sensorhub->batch_state[id].penul_len;
} else {
/*
* Push first sample in the batch to the,
* kfifo, it's guaranteed to be correct, the
* rest will follow later on.
*/
sample_idx = 1;
batch_len = 1;
cros_sensorhub_send_sample(sensorhub,
batch_start);
batch_start++;
}
/* Find all samples have the same timestamp. */
for (s = batch_start; s < last_out; s++) {
if (s->sensor_id != id)
/*
* Skip over other sensor types that
* are interleaved, don't count them.
*/
continue;
if (s->timestamp != batch_timestamp)
/* we discovered the next batch */
break;
if (s->flag & MOTIONSENSE_SENSOR_FLAG_FLUSH)
/* break on flush packets */
break;
batch_end = s;
batch_len++;
}
if (batch_len == 1)
goto done_with_this_batch;
/* Can we calculate period? */
if (sensorhub->batch_state[id].last_len == 0) {
dev_warn(sensorhub->dev, "Sensor %d: lost %d samples when spreading\n",
id, batch_len - 1);
goto done_with_this_batch;
/*
* Note: we're dropping the rest of the samples
* in this batch since we have no idea where
* they're supposed to go without a period
* calculation.
*/
}
sample_period = div_s64(batch_timestamp -
sensorhub->batch_state[id].last_ts,
sensorhub->batch_state[id].last_len);
dev_dbg(sensorhub->dev,
"Adjusting %d samples, sensor %d last_batch @%lld (%d samples) batch_timestamp=%lld => period=%lld\n",
batch_len, id,
sensorhub->batch_state[id].last_ts,
sensorhub->batch_state[id].last_len,
batch_timestamp,
sample_period);
/*
* Adjust timestamps of the samples then push them to
* kfifo.
*/
for (s = batch_start; s <= batch_end; s++) {
if (s->sensor_id != id)
/*
* Skip over other sensor types that
* are interleaved, don't change them.
*/
continue;
s->timestamp = batch_timestamp +
sample_period * sample_idx;
sample_idx++;
cros_sensorhub_send_sample(sensorhub, s);
}
done_with_this_batch:
sensorhub->batch_state[id].penul_ts =
sensorhub->batch_state[id].last_ts;
sensorhub->batch_state[id].penul_len =
sensorhub->batch_state[id].last_len;
sensorhub->batch_state[id].last_ts =
batch_timestamp;
sensorhub->batch_state[id].last_len = batch_len;
next_batch_start = batch_end + 1;
}
}
}
/*
* cros_ec_sensor_ring_spread_add_legacy: Calculate proper timestamps then
* add to ringbuffer (legacy).
*
* Note: This assumes we're running old firmware, where timestamp
* is inserted after its sample(s)e. There can be several samples between
* timestamps, so several samples can have the same timestamp.
*
* timestamp | count
* -----------------
* 1st sample --> TS1 | 1
* TS2 | 2
* TS2 | 3
* TS3 | 4
* last_out -->
*
*
* We spread time for the samples using period p = (current - TS1)/4.
* between TS1 and TS2: [TS1+p/4, TS1+2p/4, TS1+3p/4, current_timestamp].
*
*/
static void
cros_ec_sensor_ring_spread_add_legacy(struct cros_ec_sensorhub *sensorhub,
unsigned long sensor_mask,
s64 current_timestamp,
struct cros_ec_sensors_ring_sample
*last_out)
{
struct cros_ec_sensors_ring_sample *out;
int i;
for_each_set_bit(i, &sensor_mask, sensorhub->sensor_num) {
s64 timestamp;
int count = 0;
s64 time_period;
for (out = sensorhub->ring; out < last_out; out++) {
if (out->sensor_id != i)
continue;
/* Timestamp to start with */
timestamp = out->timestamp;
out++;
count = 1;
break;
}
for (; out < last_out; out++) {
/* Find last sample. */
if (out->sensor_id != i)
continue;
count++;
}
if (count == 0)
continue;
/* Spread uniformly between the first and last samples. */
time_period = div_s64(current_timestamp - timestamp, count);
for (out = sensorhub->ring; out < last_out; out++) {
if (out->sensor_id != i)
continue;
timestamp += time_period;
out->timestamp = timestamp;
}
}
/* Push the event into the kfifo */
for (out = sensorhub->ring; out < last_out; out++)
cros_sensorhub_send_sample(sensorhub, out);
}
/**
* cros_ec_sensorhub_ring_handler() - The trigger handler function
*
* @sensorhub: Sensor Hub object.
*
* Called by the notifier, process the EC sensor FIFO queue.
*/
static void cros_ec_sensorhub_ring_handler(struct cros_ec_sensorhub *sensorhub)
{
struct ec_response_motion_sense_fifo_info *fifo_info =
sensorhub->fifo_info;
struct cros_ec_dev *ec = sensorhub->ec;
ktime_t fifo_timestamp, current_timestamp;
int i, j, number_data, ret;
unsigned long sensor_mask = 0;
struct ec_response_motion_sensor_data *in;
struct cros_ec_sensors_ring_sample *out, *last_out;
mutex_lock(&sensorhub->cmd_lock);
/* Get FIFO information if there are lost vectors. */
if (fifo_info->total_lost) {
int fifo_info_length =
sizeof(struct ec_response_motion_sense_fifo_info) +
sizeof(u16) * sensorhub->sensor_num;
/* Need to retrieve the number of lost vectors per sensor */
sensorhub->params->cmd = MOTIONSENSE_CMD_FIFO_INFO;
sensorhub->msg->outsize = 1;
sensorhub->msg->insize = fifo_info_length;
if (cros_ec_cmd_xfer_status(ec->ec_dev, sensorhub->msg) < 0)
goto error;
memcpy(fifo_info, &sensorhub->resp->fifo_info,
fifo_info_length);
/*
* Update collection time, will not be as precise as the
* non-error case.
*/
fifo_timestamp = cros_ec_get_time_ns();
} else {
fifo_timestamp = sensorhub->fifo_timestamp[
CROS_EC_SENSOR_NEW_TS];
}
if (fifo_info->count > sensorhub->fifo_size ||
fifo_info->size != sensorhub->fifo_size) {
dev_warn(sensorhub->dev,
"Mismatch EC data: count %d, size %d - expected %d\n",
fifo_info->count, fifo_info->size,
sensorhub->fifo_size);
goto error;
}
/* Copy elements in the main fifo */
current_timestamp = sensorhub->fifo_timestamp[CROS_EC_SENSOR_LAST_TS];
out = sensorhub->ring;
for (i = 0; i < fifo_info->count; i += number_data) {
sensorhub->params->cmd = MOTIONSENSE_CMD_FIFO_READ;
sensorhub->params->fifo_read.max_data_vector =
fifo_info->count - i;
sensorhub->msg->outsize =
sizeof(struct ec_params_motion_sense);
sensorhub->msg->insize =
sizeof(sensorhub->resp->fifo_read) +
sensorhub->params->fifo_read.max_data_vector *
sizeof(struct ec_response_motion_sensor_data);
ret = cros_ec_cmd_xfer_status(ec->ec_dev, sensorhub->msg);
if (ret < 0) {
dev_warn(sensorhub->dev, "Fifo error: %d\n", ret);
break;
}
number_data = sensorhub->resp->fifo_read.number_data;
if (number_data == 0) {
dev_dbg(sensorhub->dev, "Unexpected empty FIFO\n");
break;
}
if (number_data > fifo_info->count - i) {
dev_warn(sensorhub->dev,
"Invalid EC data: too many entry received: %d, expected %d\n",
number_data, fifo_info->count - i);
break;
}
if (out + number_data >
sensorhub->ring + fifo_info->count) {
dev_warn(sensorhub->dev,
"Too many samples: %d (%zd data) to %d entries for expected %d entries\n",
i, out - sensorhub->ring, i + number_data,
fifo_info->count);
break;
}
for (in = sensorhub->resp->fifo_read.data, j = 0;
j < number_data; j++, in++) {
if (cros_ec_sensor_ring_process_event(
sensorhub, fifo_info,
fifo_timestamp,
¤t_timestamp,
in, out)) {
sensor_mask |= BIT(in->sensor_num);
out++;
}
}
}
mutex_unlock(&sensorhub->cmd_lock);
last_out = out;
if (out == sensorhub->ring)
/* Unexpected empty FIFO. */
goto ring_handler_end;
/*
* Check if current_timestamp is ahead of the last sample. Normally,
* the EC appends a timestamp after the last sample, but if the AP
* is slow to respond to the IRQ, the EC may have added new samples.
* Use the FIFO info timestamp as last timestamp then.
*/
if (!sensorhub->tight_timestamps &&
(last_out - 1)->timestamp == current_timestamp)
current_timestamp = fifo_timestamp;
/* Warn on lost samples. */
if (fifo_info->total_lost)
for (i = 0; i < sensorhub->sensor_num; i++) {
if (fifo_info->lost[i]) {
dev_warn_ratelimited(sensorhub->dev,
"Sensor %d: lost: %d out of %d\n",
i, fifo_info->lost[i],
fifo_info->total_lost);
if (sensorhub->tight_timestamps)
sensorhub->batch_state[i].last_len = 0;
}
}
/*
* Spread samples in case of batching, then add them to the
* ringbuffer.
*/
if (sensorhub->tight_timestamps)
cros_ec_sensor_ring_spread_add(sensorhub, sensor_mask,
last_out);
else
cros_ec_sensor_ring_spread_add_legacy(sensorhub, sensor_mask,
current_timestamp,
last_out);
ring_handler_end:
sensorhub->fifo_timestamp[CROS_EC_SENSOR_LAST_TS] = current_timestamp;
return;
error:
mutex_unlock(&sensorhub->cmd_lock);
}
static int cros_ec_sensorhub_event(struct notifier_block *nb,
unsigned long queued_during_suspend,
void *_notify)
{
struct cros_ec_sensorhub *sensorhub;
struct cros_ec_device *ec_dev;
sensorhub = container_of(nb, struct cros_ec_sensorhub, notifier);
ec_dev = sensorhub->ec->ec_dev;
if (ec_dev->event_data.event_type != EC_MKBP_EVENT_SENSOR_FIFO)
return NOTIFY_DONE;
if (ec_dev->event_size != sizeof(ec_dev->event_data.data.sensor_fifo)) {
dev_warn(ec_dev->dev, "Invalid fifo info size\n");
return NOTIFY_DONE;
}
if (queued_during_suspend)
return NOTIFY_OK;
memcpy(sensorhub->fifo_info, &ec_dev->event_data.data.sensor_fifo.info,
sizeof(*sensorhub->fifo_info));
sensorhub->fifo_timestamp[CROS_EC_SENSOR_NEW_TS] =
ec_dev->last_event_time;
cros_ec_sensorhub_ring_handler(sensorhub);
return NOTIFY_OK;
}
/**
* cros_ec_sensorhub_ring_allocate() - Prepare the FIFO functionality if the EC
* supports it.
*
* @sensorhub : Sensor Hub object.
*
* Return: 0 on success.
*/
int cros_ec_sensorhub_ring_allocate(struct cros_ec_sensorhub *sensorhub)
{
int fifo_info_length =
sizeof(struct ec_response_motion_sense_fifo_info) +
sizeof(u16) * sensorhub->sensor_num;
/* Allocate the array for lost events. */
sensorhub->fifo_info = devm_kzalloc(sensorhub->dev, fifo_info_length,
GFP_KERNEL);
if (!sensorhub->fifo_info)
return -ENOMEM;
/*
* Allocate the callback area based on the number of sensors.
* Add one for the sensor ring.
*/
sensorhub->push_data = devm_kcalloc(sensorhub->dev,
sensorhub->sensor_num,
sizeof(*sensorhub->push_data),
GFP_KERNEL);
if (!sensorhub->push_data)
return -ENOMEM;
sensorhub->tight_timestamps = cros_ec_check_features(
sensorhub->ec,
EC_FEATURE_MOTION_SENSE_TIGHT_TIMESTAMPS);
if (sensorhub->tight_timestamps) {
sensorhub->batch_state = devm_kcalloc(sensorhub->dev,
sensorhub->sensor_num,
sizeof(*sensorhub->batch_state),
GFP_KERNEL);
if (!sensorhub->batch_state)
return -ENOMEM;
}
return 0;
}
/**
* cros_ec_sensorhub_ring_add() - Add the FIFO functionality if the EC
* supports it.
*
* @sensorhub : Sensor Hub object.
*
* Return: 0 on success.
*/
int cros_ec_sensorhub_ring_add(struct cros_ec_sensorhub *sensorhub)
{
struct cros_ec_dev *ec = sensorhub->ec;
int ret;
int fifo_info_length =
sizeof(struct ec_response_motion_sense_fifo_info) +
sizeof(u16) * sensorhub->sensor_num;
/* Retrieve FIFO information */
sensorhub->msg->version = 2;
sensorhub->params->cmd = MOTIONSENSE_CMD_FIFO_INFO;
sensorhub->msg->outsize = 1;
sensorhub->msg->insize = fifo_info_length;
ret = cros_ec_cmd_xfer_status(ec->ec_dev, sensorhub->msg);
if (ret < 0)
return ret;
/*
* Allocate the full fifo. We need to copy the whole FIFO to set
* timestamps properly.
*/
sensorhub->fifo_size = sensorhub->resp->fifo_info.size;
sensorhub->ring = devm_kcalloc(sensorhub->dev, sensorhub->fifo_size,
sizeof(*sensorhub->ring), GFP_KERNEL);
if (!sensorhub->ring)
return -ENOMEM;
sensorhub->fifo_timestamp[CROS_EC_SENSOR_LAST_TS] =
cros_ec_get_time_ns();
/* Register the notifier that will act as a top half interrupt. */
sensorhub->notifier.notifier_call = cros_ec_sensorhub_event;
ret = blocking_notifier_chain_register(&ec->ec_dev->event_notifier,
&sensorhub->notifier);
if (ret < 0)
return ret;
/* Start collection samples. */
return cros_ec_sensorhub_ring_fifo_enable(sensorhub, true);
}
void cros_ec_sensorhub_ring_remove(void *arg)
{
struct cros_ec_sensorhub *sensorhub = arg;
struct cros_ec_device *ec_dev = sensorhub->ec->ec_dev;
/* Disable the ring, prevent EC interrupt to the AP for nothing. */
cros_ec_sensorhub_ring_fifo_enable(sensorhub, false);
blocking_notifier_chain_unregister(&ec_dev->event_notifier,
&sensorhub->notifier);
}
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