linux-kernel - [PATCH v2 1/2] interconnect: qcom: bcm-voter: Improve enable

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Message-Id: <20230811-topic-icc_fix_1he-v2-1-0620af8ac133@linaro.org>
Date:   Sat, 12 Aug 2023 01:16:15 +0200
From:   Konrad Dybcio <konrad.dybcio@...aro.org>
To:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Georgi Djakov <djakov@...nel.org>,
        Mike Tipton <quic_mdtipton@...cinc.com>,
        Neil Armstrong <neil.armstrong@...aro.org>
Cc:     Marijn Suijten <marijn.suijten@...ainline.org>,
        linux-arm-msm@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        Bjorn Andersson <quic_bjorande@...cinc.com>
Subject: [PATCH v2 1/2] interconnect: qcom: bcm-voter: Improve enable_mask
 handling

We don't need all the complex arithmetic for BCMs utilizing enable_mask,
as all we need to do is to determine whether there's any user (or
keepalive) asking for it to be on.

Separate the logic for such BCMs for a small speed boost.

Suggested-by: Bjorn Andersson <quic_bjorande@...cinc.com>
Reviewed-by: Bjorn Andersson <quic_bjorande@...cinc.com>
Signed-off-by: Konrad Dybcio <konrad.dybcio@...aro.org>
---
 drivers/interconnect/qcom/bcm-voter.c | 43 +++++++++++++++++++++++++++++------
 1 file changed, 36 insertions(+), 7 deletions(-)

diff --git a/drivers/interconnect/qcom/bcm-voter.c b/drivers/interconnect/qcom/bcm-voter.c
index d5f2a6b5376b..d857eb8838b9 100644
--- a/drivers/interconnect/qcom/bcm-voter.c
+++ b/drivers/interconnect/qcom/bcm-voter.c
@@ -58,6 +58,36 @@ static u64 bcm_div(u64 num, u32 base)
 	return num;
 }
 
+/* BCMs with enable_mask use one-hot-encoding for on/off signaling */
+static void bcm_aggregate_mask(struct qcom_icc_bcm *bcm)
+{
+	struct qcom_icc_node *node;
+	int bucket, i;
+
+	for (bucket = 0; bucket < QCOM_ICC_NUM_BUCKETS; bucket++) {
+		bcm->vote_x[bucket] = 0;
+		bcm->vote_y[bucket] = 0;
+
+		for (i = 0; i < bcm->num_nodes; i++) {
+			node = bcm->nodes[i];
+
+			/* If any vote in this bucket exists, keep the BCM enabled */
+			if (node->sum_avg[bucket] || node->max_peak[bucket]) {
+				bcm->vote_x[bucket] = 0;
+				bcm->vote_y[bucket] = bcm->enable_mask;
+				break;
+			}
+		}
+	}
+
+	if (bcm->keepalive) {
+		bcm->vote_x[QCOM_ICC_BUCKET_AMC] = 1;
+		bcm->vote_x[QCOM_ICC_BUCKET_WAKE] = 1;
+		bcm->vote_y[QCOM_ICC_BUCKET_AMC] = 1;
+		bcm->vote_y[QCOM_ICC_BUCKET_WAKE] = 1;
+	}
+}
+
 static void bcm_aggregate(struct qcom_icc_bcm *bcm)
 {
 	struct qcom_icc_node *node;
@@ -83,11 +113,6 @@ static void bcm_aggregate(struct qcom_icc_bcm *bcm)
 
 		temp = agg_peak[bucket] * bcm->vote_scale;
 		bcm->vote_y[bucket] = bcm_div(temp, bcm->aux_data.unit);
-
-		if (bcm->enable_mask && (bcm->vote_x[bucket] || bcm->vote_y[bucket])) {
-			bcm->vote_x[bucket] = 0;
-			bcm->vote_y[bucket] = bcm->enable_mask;
-		}
 	}
 
 	if (bcm->keepalive && bcm->vote_x[QCOM_ICC_BUCKET_AMC] == 0 &&
@@ -260,8 +285,12 @@ int qcom_icc_bcm_voter_commit(struct bcm_voter *voter)
 		return 0;
 
 	mutex_lock(&voter->lock);
-	list_for_each_entry(bcm, &voter->commit_list, list)
-		bcm_aggregate(bcm);
+	list_for_each_entry(bcm, &voter->commit_list, list) {
+		if (bcm->enable_mask)
+			bcm_aggregate_mask(bcm);
+		else
+			bcm_aggregate(bcm);
+	}
 
 	/*
 	 * Pre sort the BCMs based on VCD for ease of generating a command list

-- 
2.41.0