diff options
Diffstat (limited to 'drivers/platform/chrome/cros_ec_sensorhub_ring.c')
| -rw-r--r-- | drivers/platform/chrome/cros_ec_sensorhub_ring.c | 1046 |
1 files changed, 1046 insertions, 0 deletions
diff --git a/drivers/platform/chrome/cros_ec_sensorhub_ring.c b/drivers/platform/chrome/cros_ec_sensorhub_ring.c new file mode 100644 index 000000000000..230e6cf3da2f --- /dev/null +++ b/drivers/platform/chrome/cros_ec_sensorhub_ring.c @@ -0,0 +1,1046 @@ +// 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> + +/* 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 noone 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 int cros_ec_sensor_ring_median_cmp(const void *pv1, const void *pv2) +{ + s64 v1 = *(s64 *)pv1; + s64 v2 = *(s64 *)pv2; + + if (v1 > v2) + return 1; + else if (v1 < v2) + return -1; + else + return 0; +} + +/* + * cros_ec_sensor_ring_median: Gets median of an array of numbers + * + * For now it's implemented using an inefficient > O(n) sort then return + * the middle element. A more optimal method would be something like + * quickselect, but given that n = 64 we can probably live with it in the + * name of clarity. + * + * Warning: the input array gets modified (sorted)! + */ +static s64 cros_ec_sensor_ring_median(s64 *array, size_t length) +{ + sort(array, length, sizeof(s64), cros_ec_sensor_ring_median_cmp, NULL); + return array[length / 2]; +} + +/* + * 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 change we'll get + * added lantency 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; + } +} + +/** + * 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 = fifo_timestamp - + fifo_info->timestamp * 1000 + + in->timestamp * 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; + } + } + + 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; + 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 + * preceeds 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, + * kifo, 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 every sample's timestamp + * is after the sample. Run if tight_timestamps == false. + * + * If there is a sample with a proper timestamp + * + * timestamp | count + * ----------------- + * older_unprocess_out --> TS1 | 1 + * TS1 | 2 + * out --> TS1 | 3 + * next_out --> TS2 | + * + * We spread time for the samples [older_unprocess_out .. out] + * between TS1 and TS2: [TS1+1/4, TS1+2/4, TS1+3/4, TS2]. + * + * If we reach the end of the samples, we compare with the + * current timestamp: + * + * older_unprocess_out --> TS1 | 1 + * TS1 | 2 + * out --> TS1 | 3 + * + * We know have [TS1+1/3, TS1+2/3, 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 older_timestamp; + s64 timestamp; + struct cros_ec_sensors_ring_sample *older_unprocess_out = + sensorhub->ring; + struct cros_ec_sensors_ring_sample *next_out; + int count = 1; + + for (out = sensorhub->ring; out < last_out; out = next_out) { + s64 time_period; + + next_out = out + 1; + if (out->sensor_id != i) + continue; + + /* Timestamp to start with */ + older_timestamp = out->timestamp; + + /* Find next sample. */ + while (next_out < last_out && next_out->sensor_id != i) + next_out++; + + if (next_out >= last_out) { + timestamp = current_timestamp; + } else { + timestamp = next_out->timestamp; + if (timestamp == older_timestamp) { + count++; + continue; + } + } + + /* + * The next sample has a new timestamp, spread the + * unprocessed samples. + */ + if (next_out < last_out) + count++; + time_period = div_s64(timestamp - older_timestamp, + count); + + for (; older_unprocess_out <= out; + older_unprocess_out++) { + if (older_unprocess_out->sensor_id != i) + continue; + older_timestamp += time_period; + older_unprocess_out->timestamp = + older_timestamp; + } + count = 1; + /* The next_out sample has a valid timestamp, skip. */ + next_out++; + older_unprocess_out = next_out; + } + } + + /* 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", + 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", + 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", + 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_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; + + /* Allocate the array for lost events. */ + sensorhub->fifo_info = devm_kzalloc(sensorhub->dev, fifo_info_length, + GFP_KERNEL); + if (!sensorhub->fifo_info) + return -ENOMEM; + + /* 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; + + /* + * Allocate the callback area based on the number of sensors. + */ + sensorhub->push_data = devm_kcalloc( + sensorhub->dev, sensorhub->sensor_num, + sizeof(*sensorhub->push_data), + GFP_KERNEL); + if (!sensorhub->push_data) + return -ENOMEM; + + sensorhub->fifo_timestamp[CROS_EC_SENSOR_LAST_TS] = + cros_ec_get_time_ns(); + + sensorhub->tight_timestamps = cros_ec_check_features( + 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; + } + + /* 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); +} |