[PATCH 4/4] interconnect: qcom: Fix small BW votes being truncated to zero

[Mike Tipton]

Small BW votes that translate to less than a single BCM unit are
currently truncated to zero. Ensure that non-zero BW requests always
result in at least a vote of 1 to BCM.

Fixes: 976daac4a1c5 ("interconnect: qcom: Consolidate interconnect RPMh 
support")
Signed-off-by: Mike Tipton <mdtip...@codeaurora.org>
---
 drivers/interconnect/qcom/bcm-voter.c | 27 +++++++++++++++++++--------
 1 file changed, 19 insertions(+), 8 deletions(-)

diff --git a/drivers/interconnect/qcom/bcm-voter.c 
b/drivers/interconnect/qcom/bcm-voter.c
index a68c858ca6b7..9e2612fe7fad 100644
--- a/drivers/interconnect/qcom/bcm-voter.c
+++ b/drivers/interconnect/qcom/bcm-voter.c
@@ -54,8 +54,20 @@ static int cmp_vcd(void *priv, struct list_head *a, struct 
list_head *b)
                return 1;
 }
 
+static u64 bcm_div(u64 num, u64 base)
+{
+       /* Ensure that small votes aren't lost. */
+       if (num && num < base)
+               return 1;
+
+       do_div(num, base);
+
+       return num;
+}
+
 static void bcm_aggregate(struct qcom_icc_bcm *bcm)
 {
+       struct qcom_icc_node *node;
        size_t i, bucket;
        u64 agg_avg[QCOM_ICC_NUM_BUCKETS] = {0};
        u64 agg_peak[QCOM_ICC_NUM_BUCKETS] = {0};
@@ -63,22 +75,21 @@ static void bcm_aggregate(struct qcom_icc_bcm *bcm)
 
        for (bucket = 0; bucket < QCOM_ICC_NUM_BUCKETS; bucket++) {
                for (i = 0; i < bcm->num_nodes; i++) {
-                       temp = bcm->nodes[i]->sum_avg[bucket] * 
bcm->aux_data.width;
-                       do_div(temp, bcm->nodes[i]->buswidth * 
bcm->nodes[i]->channels);
+                       node = bcm->nodes[i];
+                       temp = bcm_div(node->sum_avg[bucket] * 
bcm->aux_data.width,
+                                      node->buswidth * node->channels);
                        agg_avg[bucket] = max(agg_avg[bucket], temp);
 
-                       temp = bcm->nodes[i]->max_peak[bucket] * 
bcm->aux_data.width;
-                       do_div(temp, bcm->nodes[i]->buswidth);
+                       temp = bcm_div(node->max_peak[bucket] * 
bcm->aux_data.width,
+                                      node->buswidth);
                        agg_peak[bucket] = max(agg_peak[bucket], temp);
                }
 
                temp = agg_avg[bucket] * bcm->vote_scale;
-               do_div(temp, bcm->aux_data.unit);
-               bcm->vote_x[bucket] = temp;
+               bcm->vote_x[bucket] = bcm_div(temp, bcm->aux_data.unit);
 
                temp = agg_peak[bucket] * bcm->vote_scale;
-               do_div(temp, bcm->aux_data.unit);
-               bcm->vote_y[bucket] = temp;
+               bcm->vote_y[bucket] = bcm_div(temp, bcm->aux_data.unit);
        }
 
        if (bcm->keepalive && bcm->vote_x[QCOM_ICC_BUCKET_AMC] == 0 &&
-- 
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