interconnect: qcom: Fix small BW votes being truncated to zero

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 <mdtipton@codeaurora.org>
Link: https://lore.kernel.org/r/20200903192149.30385-2-mdtipton@codeaurora.org
Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>

diff --git a/drivers/interconnect/qcom/bcm-voter.c b/drivers/interconnect/qcom/bcm-voter.c
index a3d2ef1d9903746e67768332872ac09376ba1b0b..609db9c95fd7a1c37c50ffd3bf25e1c2956c6a8c 100644 (file)
--- a/drivers/interconnect/qcom/bcm-voter.c
+++ b/drivers/interconnect/qcom/bcm-voter.c
@@ -52,8 +52,20 @@ static int cmp_vcd(void *priv, struct list_head *a, struct list_head *b)
                return 1;
 }
 
+static u64 bcm_div(u64 num, u32 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};
@@ -61,22 +73,21 @@ 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] * 1000ULL;
-               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] * 1000ULL;
-               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 &&