[PATCH 5.8 036/177] interconnect: qcom: Fix small BW votes being truncated to zero

Greg Kroah-Hartman
2020-09-15T23:44:08Z

From: Mike Tipton <mdtipton@codeaurora.org>

[ Upstream commit 91e045b93db79a2ef66e045ad0d1f8f9d348e1f4 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.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 2a11a63e7217a..b360dc34c90c7 100644
--- 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 &&
--
2.25.1