[PATCH v3 4/6] firmware: arm_scmi: add SCMIv3.0 Sensors timestamped reads

Cristian Marussi
2020-11-18T16:31:27Z

Add new .reading_get_timestamped() method to sensor_ops to support SCMIv3.0
timestamped reads.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
V2 --> v3
- setting rx_size to 0 in sensor_reading_get to allow fw to send
both v2 and v3 replies...even if sensor_reading_get() only handles
v2 spec and returns one single value
- using get_unaligned_le64 in lieu of le64_to_cpu
- removed refs to v2.1
---
drivers/firmware/arm_scmi/sensors.c | 137 ++++++++++++++++++++++++++--
include/linux/scmi_protocol.h | 22 +++++
2 files changed, 152 insertions(+), 7 deletions(-)

diff --git a/drivers/firmware/arm_scmi/sensors.c b/drivers/firmware/arm_scmi/sensors.c
index 1c83aaae0012..0adc545116a4 100644
--- a/drivers/firmware/arm_scmi/sensors.c
+++ b/drivers/firmware/arm_scmi/sensors.c
@@ -156,6 +156,27 @@ struct scmi_msg_sensor_reading_get {
#define SENSOR_READ_ASYNC BIT(0)
};

+struct scmi_resp_sensor_reading_get {
+ __le64 readings;
+};
+
+struct scmi_resp_sensor_reading_complete {
+ __le32 id;
+ __le64 readings;
+};
+
+struct scmi_sensor_reading_le {
+ __le32 sensor_value_low;
+ __le32 sensor_value_high;
+ __le32 timestamp_low;
+ __le32 timestamp_high;
+};
+
+struct scmi_resp_sensor_reading_complete_v3 {
+ __le32 id;
+ struct scmi_sensor_reading_le readings[];
+};
+
struct scmi_sensor_trip_notify_payld {
__le32 agent_id;
__le32 sensor_id;
@@ -576,6 +597,21 @@ scmi_sensor_trip_point_config(const struct scmi_handle *handle, u32 sensor_id,
return ret;
}

+/**
+ * scmi_sensor_reading_get - Read scalar sensor value
+ * @handle: Platform handle
+ * @sensor_id: Sensor ID
+ * @value: The 64bit value sensor reading
+ *
+ * This function returns a single 64 bit reading value representing the sensor
+ * value; if the platform SCMI Protocol implementation and the sensor support
+ * multiple axis and timestamped-reads, this just returns the first axis while
+ * dropping the timestamp value.
+ * Use instead the @scmi_sensor_reading_get_timestamped to retrieve the array of
+ * timestamped multi-axis values.
+ *
+ * Return: 0 on Success
+ */
static int scmi_sensor_reading_get(const struct scmi_handle *handle,
u32 sensor_id, u64 *value)
{
@@ -586,25 +622,111 @@ static int scmi_sensor_reading_get(const struct scmi_handle *handle,
struct scmi_sensor_info *s = si->sensors + sensor_id;

ret = scmi_xfer_get_init(handle, SENSOR_READING_GET,
- SCMI_PROTOCOL_SENSOR, sizeof(*sensor),
- sizeof(u64), &t);
+ SCMI_PROTOCOL_SENSOR, sizeof(*sensor), 0, &t);
if (ret)
return ret;

sensor = t->tx.buf;
sensor->id = cpu_to_le32(sensor_id);
+ if (s->async) {
+ sensor->flags = cpu_to_le32(SENSOR_READ_ASYNC);
+ ret = scmi_do_xfer_with_response(handle, t);
+ if (!ret) {
+ struct scmi_resp_sensor_reading_complete *resp;
+
+ resp = t->rx.buf;
+ if (le32_to_cpu(resp->id) == sensor_id)
+ *value = get_unaligned_le64(&resp->readings);
+ else
+ ret = -EPROTO;
+ }
+ } else {
+ sensor->flags = cpu_to_le32(0);
+ ret = scmi_do_xfer(handle, t);
+ if (!ret) {
+ struct scmi_resp_sensor_reading_get *resp;
+
+ resp = t->rx.buf;
+ *value = get_unaligned_le64(&resp->readings);
+ }
+ }

+ scmi_xfer_put(handle, t);
+ return ret;
+}
+
+static inline void
+scmi_parse_sensor_readings(struct scmi_sensor_reading *out,
+ const struct scmi_sensor_reading_le *in)
+{
+ out->value = get_unaligned_le64((void *)&in->sensor_value_low);
+ out->timestamp = get_unaligned_le64((void *)&in->timestamp_low);
+}
+
+/**
+ * scmi_sensor_reading_get_timestamped - Read multiple-axis timestamped values
+ * @handle: Platform handle
+ * @sensor_id: Sensor ID
+ * @count: The length of the provided @readings array
+ * @readings: An array of elements each representing a timestamped per-axis
+ * reading of type @struct scmi_sensor_reading.
+ * Returned readings are ordered as the @axis descriptors array
+ * included in @struct scmi_sensor_info and the max number of
+ * returned elements is min(@count, @num_axis); ideally the provided
+ * array should be of length @count equal to @num_axis.
+ *
+ * Return: 0 on Success
+ */
+static int
+scmi_sensor_reading_get_timestamped(const struct scmi_handle *handle,
+ u32 sensor_id, u8 count,
+ struct scmi_sensor_reading *readings)
+{
+ int ret;
+ struct scmi_xfer *t;
+ struct scmi_msg_sensor_reading_get *sensor;
+ struct sensors_info *si = handle->sensor_priv;
+ struct scmi_sensor_info *s = si->sensors + sensor_id;
+
+ if (!count || !readings ||
+ (!s->num_axis && count > 1) || (s->num_axis && count > s->num_axis))
+ return -EINVAL;
+
+ ret = scmi_xfer_get_init(handle, SENSOR_READING_GET,
+ SCMI_PROTOCOL_SENSOR, sizeof(*sensor), 0, &t);
+ if (ret)
+ return ret;
+
+ sensor = t->tx.buf;
+ sensor->id = cpu_to_le32(sensor_id);
if (s->async) {
sensor->flags = cpu_to_le32(SENSOR_READ_ASYNC);
ret = scmi_do_xfer_with_response(handle, t);
- if (!ret)
- *value = get_unaligned_le64((void *)
- ((__le32 *)t->rx.buf + 1));
+ if (!ret) {
+ int i;
+ struct scmi_resp_sensor_reading_complete_v3 *resp;
+
+ resp = t->rx.buf;
+ /* Retrieve only the number of requested axis anyway */
+ if (le32_to_cpu(resp->id) == sensor_id)
+ for (i = 0; i < count; i++)
+ scmi_parse_sensor_readings(&readings[i],
+ &resp->readings[i]);
+ else
+ ret = -EPROTO;
+ }
} else {
sensor->flags = cpu_to_le32(0);
ret = scmi_do_xfer(handle, t);
- if (!ret)
- *value = get_unaligned_le64(t->rx.buf);
+ if (!ret) {
+ int i;
+ struct scmi_sensor_reading_le *resp_readings;
+
+ resp_readings = t->rx.buf;
+ for (i = 0; i < count; i++)
+ scmi_parse_sensor_readings(&readings[i],
+ &resp_readings[i]);
+ }
}

scmi_xfer_put(handle, t);
@@ -631,6 +753,7 @@ static const struct scmi_sensor_ops sensor_ops = {
.info_get = scmi_sensor_info_get,
.trip_point_config = scmi_sensor_trip_point_config,
.reading_get = scmi_sensor_reading_get,
+ .reading_get_timestamped = scmi_sensor_reading_get_timestamped,
};

static int scmi_sensor_set_notify_enabled(const struct scmi_handle *handle,
diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h
index 53cc5ce0e494..072d8f9fc42a 100644
--- a/include/linux/scmi_protocol.h
+++ b/include/linux/scmi_protocol.h
@@ -149,6 +149,20 @@ struct scmi_power_ops {
u32 *state);
};

+/**
+ * scmi_sensor_reading - represent a timestamped read
+ *
+ * Used by @reading_get_timestamped method.
+ *
+ * @value: The signed value sensor read.
+ * @timestamp: An unsigned timestamp for the sensor read, as provided by
+ * SCMI platform. Set to zero when not available.
+ */
+struct scmi_sensor_reading {
+ long long value;
+ unsigned long long timestamp;
+};
+
/**
* scmi_range_attrs - specifies a sensor or axis values' range
* @min_range: The minimum value which can be represented by the sensor/axis.
@@ -391,6 +405,11 @@ enum scmi_sensor_class {
* @info_get: get the information of the specified sensor
* @trip_point_config: selects and configures a trip-point of interest
* @reading_get: gets the current value of the sensor
+ * @reading_get_timestamped: gets the current value and timestamp, when
+ * available, of the sensor. (as of v3.0 spec)
+ * Supports multi-axis sensors for sensors which
+ * supports it and if the @reading array size of
+ * @count entry equals the sensor num_axis
*/
struct scmi_sensor_ops {
int (*count_get)(const struct scmi_handle *handle);
@@ -400,6 +419,9 @@ struct scmi_sensor_ops {
u32 sensor_id, u8 trip_id, u64 trip_value);
int (*reading_get)(const struct scmi_handle *handle, u32 sensor_id,
u64 *value);
+ int (*reading_get_timestamped)(const struct scmi_handle *handle,
+ u32 sensor_id, u8 count,
+ struct scmi_sensor_reading *readings);
};

/**
--
2.17.1