[PATCH v12 10/25] firmware: arm_scmi: Add support for Telemetry reset

[Cristian Marussi <cristian.marussi@arm.com>]

Add support for Telemetry operations needed to request platform to
reset telemetry current configuration and data events values.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
v11 --> v12
 - using config_mtx to sync with ongoing configurations
 - use proper helpers to update cache state
v10 --> v11
 - protect TDE updates on reset
 - use des_enable mutex when clearing des cache
 - zero also active_update_interval
v8 --> v9
 - add a commment on why NOT unlinking UUID
v6 --> v7
 - add proper cleanup of sid/offs/uuids and caches on RESET
v5 --> v6
 - added missing reset of global state
v3 --> v4
 - reset tracked Telemetry DE state
v2 --> v3
 - split from monolithic Telemetry patch
 - use scmi_telemetry_de_unlink
---
 drivers/firmware/arm_scmi/telemetry.c | 80 +++++++++++++++++++++++++++
 include/linux/scmi_protocol.h         |  2 +
 2 files changed, 82 insertions(+)

diff --git a/drivers/firmware/arm_scmi/telemetry.c b/drivers/firmware/arm_scmi/telemetry.c
index c4981d3f5457..3e0c3c42e5a7 100644
--- a/drivers/firmware/arm_scmi/telemetry.c
+++ b/drivers/firmware/arm_scmi/telemetry.c
@@ -3138,6 +3138,85 @@ static int scmi_telemetry_des_sample_get(const struct scmi_protocol_handle *ph,
 	return ret;
 }
 
+static void scmi_telemetry_local_resources_reset(struct telemetry_info *ti)
+{
+	struct scmi_telemetry_res_info *rinfo;
+
+	/* Stall concurrent configuration request */
+	guard(mutex)(&ti->config_mtx);
+
+	ti->info.enabled = false;
+	ti->info.notif_enabled = false;
+	ti->info.current_mode = SCMI_TLM_ONDEMAND;
+	ti->info.active_update_interval = 0;
+
+	/* Get rinfo as it is...without triggering an enumeration */
+	rinfo = __scmi_telemetry_resources_get(ti);
+
+	/* Clear all local state...*/
+	for (int i = 0; i < rinfo->num_des; i++) {
+		struct telemetry_de *tde = to_tde(rinfo->des[i]);
+
+		scoped_guard(mutex, &tde->mtx) {
+			tde->last_ts = 0;
+			tde->last_val = 0;
+			tde->last_magic = 0;
+			if (!tde->de.fc_support) {
+				tde->sid = SHMTI_ID_INVALID;
+				tde->base = NULL;
+				tde->offset = 0;
+				tde->eplg = NULL;
+			}
+
+			scmi_telemetry_de_state_update(ti, ENA_STATE,
+						       &tde->de.enabled, false);
+
+			if (tde->de.tstamp_support)
+				scmi_telemetry_de_state_update(ti, ENA_TSTAMP,
+							       &tde->de.tstamp_enabled,
+							       false);
+		}
+
+		/*
+		 * Unlinking ONLY BLK_TS lines since, per the SCMI spec, the
+		 * UUID/DE associations are permanent within the same session
+		 * boot: after a reset has cleared the server-side configuration
+		 * the next time SHMTIs will be re-populated, these same UUID/DE
+		 * associations will be re-instated.
+		 */
+		scmi_telemetry_blkts_unlink(tde);
+	}
+
+	for (int i = 0; i < rinfo->num_groups; i++) {
+		rinfo->grps[i].enabled = false;
+		rinfo->grps[i].tstamp_enabled = false;
+		rinfo->grps[i].current_mode = SCMI_TLM_ONDEMAND;
+		rinfo->grps[i].active_update_interval = 0;
+	}
+}
+
+static int scmi_telemetry_reset(const struct scmi_protocol_handle *ph)
+{
+	struct scmi_xfer *t;
+	int ret;
+
+	ret = ph->xops->xfer_get_init(ph, TELEMETRY_RESET, sizeof(u32), 0, &t);
+	if (ret)
+		return ret;
+
+	put_unaligned_le32(0, t->tx.buf);
+	ret = ph->xops->do_xfer(ph, t);
+	if (!ret) {
+		struct telemetry_info *ti = ph->get_priv(ph);
+
+		scmi_telemetry_local_resources_reset(ti);
+	}
+
+	ph->xops->xfer_put(ph, t);
+
+	return ret;
+}
+
 static const struct scmi_telemetry_proto_ops tlm_proto_ops = {
 	.info_get = scmi_telemetry_info_get,
 	.de_lookup = scmi_telemetry_de_lookup,
@@ -3148,6 +3227,7 @@ static const struct scmi_telemetry_proto_ops tlm_proto_ops = {
 	.de_data_read = scmi_telemetry_de_data_read,
 	.des_bulk_read = scmi_telemetry_des_bulk_read,
 	.des_sample_get = scmi_telemetry_des_sample_get,
+	.reset = scmi_telemetry_reset,
 };
 
 /**
diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h
index c401d04758c5..5a2787b30120 100644
--- a/include/linux/scmi_protocol.h
+++ b/include/linux/scmi_protocol.h
@@ -1016,6 +1016,7 @@ struct scmi_telemetry_de_sample {
  *		    the ones belonging to a specific group when provided.
  *		    This causes an immediate update platform-side of all the
  *		    enabled DEs.
+ * @reset: reset configuration and telemetry data.
  */
 struct scmi_telemetry_proto_ops {
 	const struct scmi_telemetry_info __must_check *(*info_get)
@@ -1043,6 +1044,7 @@ struct scmi_telemetry_proto_ops {
 	int __must_check (*des_sample_get)(const struct scmi_protocol_handle *ph,
 					   int grp_id, int *num_samples,
 					   struct scmi_telemetry_de_sample *samples);
+	int (*reset)(const struct scmi_protocol_handle *ph);
 };
 
 /**
-- 
2.54.0