cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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cros_ec_sensorhub.h (6259B)

      1/* SPDX-License-Identifier: GPL-2.0 */
      2/*
      3 * Chrome OS EC MEMS Sensor Hub driver.
      4 *
      5 * Copyright 2019 Google LLC
      6 */
      7
      8#ifndef __LINUX_PLATFORM_DATA_CROS_EC_SENSORHUB_H
      9#define __LINUX_PLATFORM_DATA_CROS_EC_SENSORHUB_H
     10
     11#include <linux/ktime.h>
     12#include <linux/mutex.h>
     13#include <linux/notifier.h>
     14#include <linux/platform_data/cros_ec_commands.h>
     15
     16struct iio_dev;
     17
     18/**
     19 * struct cros_ec_sensor_platform - ChromeOS EC sensor platform information.
     20 * @sensor_num: Id of the sensor, as reported by the EC.
     21 */
     22struct cros_ec_sensor_platform {
     23	u8 sensor_num;
     24};
     25
     26/**
     27 * typedef cros_ec_sensorhub_push_data_cb_t - Callback function to send datum
     28 *					      to specific sensors.
     29 *
     30 * @indio_dev: The IIO device that will process the sample.
     31 * @data: Vector array of the ring sample.
     32 * @timestamp: Timestamp in host timespace when the sample was acquired by
     33 *             the EC.
     34 */
     35typedef int (*cros_ec_sensorhub_push_data_cb_t)(struct iio_dev *indio_dev,
     36						s16 *data,
     37						s64 timestamp);
     38
     39struct cros_ec_sensorhub_sensor_push_data {
     40	struct iio_dev *indio_dev;
     41	cros_ec_sensorhub_push_data_cb_t push_data_cb;
     42};
     43
     44enum {
     45	CROS_EC_SENSOR_LAST_TS,
     46	CROS_EC_SENSOR_NEW_TS,
     47	CROS_EC_SENSOR_ALL_TS
     48};
     49
     50struct cros_ec_sensors_ring_sample {
     51	u8  sensor_id;
     52	u8  flag;
     53	s16 vector[3];
     54	s64 timestamp;
     55} __packed;
     56
     57/* State used for cros_ec_ring_fix_overflow */
     58struct cros_ec_sensors_ec_overflow_state {
     59	s64 offset;
     60	s64 last;
     61};
     62
     63/* Length of the filter, how long to remember entries for */
     64#define CROS_EC_SENSORHUB_TS_HISTORY_SIZE 64
     65
     66/**
     67 * struct cros_ec_sensors_ts_filter_state - Timestamp filetr state.
     68 *
     69 * @x_offset: x is EC interrupt time. x_offset its last value.
     70 * @y_offset: y is the difference between AP and EC time, y_offset its last
     71 *            value.
     72 * @x_history: The past history of x, relative to x_offset.
     73 * @y_history: The past history of y, relative to y_offset.
     74 * @m_history: rate between y and x.
     75 * @history_len: Amount of valid historic data in the arrays.
     76 * @temp_buf: Temporary buffer used when updating the filter.
     77 * @median_m: median value of m_history
     78 * @median_error: final error to apply to AP interrupt timestamp to get the
     79 *                "true timestamp" the event occurred.
     80 */
     81struct cros_ec_sensors_ts_filter_state {
     82	s64 x_offset, y_offset;
     83	s64 x_history[CROS_EC_SENSORHUB_TS_HISTORY_SIZE];
     84	s64 y_history[CROS_EC_SENSORHUB_TS_HISTORY_SIZE];
     85	s64 m_history[CROS_EC_SENSORHUB_TS_HISTORY_SIZE];
     86	int history_len;
     87
     88	s64 temp_buf[CROS_EC_SENSORHUB_TS_HISTORY_SIZE];
     89
     90	s64 median_m;
     91	s64 median_error;
     92};
     93
     94/* struct cros_ec_sensors_ts_batch_state - State of batch of a single sensor.
     95 *
     96 * Use to store information to batch data using median fileter information.
     97 *
     98 * @penul_ts: last but one batch timestamp (penultimate timestamp).
     99 *	      Used for timestamp spreading calculations
    100 *	      when a batch shows up.
    101 * @penul_len: last but one batch length.
    102 * @last_ts: Last batch timestam.
    103 * @last_len: Last batch length.
    104 * @newest_sensor_event: Last sensor timestamp.
    105 */
    106struct cros_ec_sensors_ts_batch_state {
    107	s64 penul_ts;
    108	int penul_len;
    109	s64 last_ts;
    110	int last_len;
    111	s64 newest_sensor_event;
    112};
    113
    114/*
    115 * struct cros_ec_sensorhub - Sensor Hub device data.
    116 *
    117 * @dev: Device object, mostly used for logging.
    118 * @ec: Embedded Controller where the hub is located.
    119 * @sensor_num: Number of MEMS sensors present in the EC.
    120 * @msg: Structure to send FIFO requests.
    121 * @params: Pointer to parameters in msg.
    122 * @resp: Pointer to responses in msg.
    123 * @cmd_lock : Lock for sending msg.
    124 * @notifier: Notifier to kick the FIFO interrupt.
    125 * @ring: Preprocessed ring to store events.
    126 * @fifo_timestamp: Array for event timestamp and spreading.
    127 * @fifo_info: Copy of FIFO information coming from the EC.
    128 * @fifo_size: Size of the ring.
    129 * @batch_state: Per sensor information of the last batches received.
    130 * @overflow_a: For handling timestamp overflow for a time (sensor events)
    131 * @overflow_b: For handling timestamp overflow for b time (ec interrupts)
    132 * @filter: Medium fileter structure.
    133 * @tight_timestamps: Set to truen when EC support tight timestamping:
    134 *		      The timestamps reported from the EC have low jitter.
    135 *		      Timestamps also come before every sample. Set either
    136 *		      by feature bits coming from the EC or userspace.
    137 * @future_timestamp_count: Statistics used to compute shaved time.
    138 *			    This occurs when timestamp interpolation from EC
    139 *			    time to AP time accidentally puts timestamps in
    140 *			    the future. These timestamps are clamped to
    141 *			    `now` and these count/total_ns maintain the
    142 *			    statistics for how much time was removed in a
    143 *			    given period.
    144 * @future_timestamp_total_ns: Total amount of time shaved.
    145 * @push_data: Array of callback to send datums to iio sensor object.
    146 */
    147struct cros_ec_sensorhub {
    148	struct device *dev;
    149	struct cros_ec_dev *ec;
    150	int sensor_num;
    151
    152	struct cros_ec_command *msg;
    153	struct ec_params_motion_sense *params;
    154	struct ec_response_motion_sense *resp;
    155	struct mutex cmd_lock;  /* Lock for protecting msg structure. */
    156
    157	struct notifier_block notifier;
    158
    159	struct cros_ec_sensors_ring_sample *ring;
    160
    161	ktime_t fifo_timestamp[CROS_EC_SENSOR_ALL_TS];
    162	struct ec_response_motion_sense_fifo_info *fifo_info;
    163	int fifo_size;
    164
    165	struct cros_ec_sensors_ts_batch_state *batch_state;
    166
    167	struct cros_ec_sensors_ec_overflow_state overflow_a;
    168	struct cros_ec_sensors_ec_overflow_state overflow_b;
    169
    170	struct cros_ec_sensors_ts_filter_state filter;
    171
    172	int tight_timestamps;
    173
    174	s32 future_timestamp_count;
    175	s64 future_timestamp_total_ns;
    176
    177	struct cros_ec_sensorhub_sensor_push_data *push_data;
    178};
    179
    180int cros_ec_sensorhub_register_push_data(struct cros_ec_sensorhub *sensorhub,
    181					 u8 sensor_num,
    182					 struct iio_dev *indio_dev,
    183					 cros_ec_sensorhub_push_data_cb_t cb);
    184
    185void cros_ec_sensorhub_unregister_push_data(struct cros_ec_sensorhub *sensorhub,
    186					    u8 sensor_num);
    187
    188int cros_ec_sensorhub_ring_allocate(struct cros_ec_sensorhub *sensorhub);
    189int cros_ec_sensorhub_ring_add(struct cros_ec_sensorhub *sensorhub);
    190void cros_ec_sensorhub_ring_remove(void *arg);
    191int cros_ec_sensorhub_ring_fifo_enable(struct cros_ec_sensorhub *sensorhub,
    192				       bool on);
    193
    194#endif   /* __LINUX_PLATFORM_DATA_CROS_EC_SENSORHUB_H */