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interconnect: qcom: icc-rpm: Fix bandwidth calculations

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Up until now, we've been aggregating the bandwidth values and only
dividing them by the bus width of the source node. This was completely
wrong, as different nodes on a given path may (and usually do) have
varying bus widths.  That in turn, resulted in the calculated clock rates
being completely bogus - usually they ended up being much higher, as
NoC_A<->NoC_B links are very wide.

Since we're not using the aggregate bandwidth value for anything other
than clock rate calculations, remodel qcom_icc_bus_aggregate() to
calculate the per-context clock rate for a given provider, taking into
account the bus width of every individual node.

Fixes: 30c8fa3ec6 ("interconnect: qcom: Add MSM8916 interconnect provider driver")
Reported-by: Stephan Gerhold <stephan@gerhold.net>
Reviewed-by: Stephan Gerhold <stephan@gerhold.net>
Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Acked-by: Georgi Djakov <djakov@kernel.org>
Link: https://lore.kernel.org/r/20230526-topic-smd_icc-v7-22-09c78c175546@linaro.org
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
This commit is contained in:
Konrad Dybcio 2023-06-19 15:04:47 +02:00 committed by Bjorn Andersson
parent 3b7480106b
commit 17fc623e0f
1 changed files with 19 additions and 40 deletions
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59
drivers/interconnect/qcom/icc-rpm.c
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@ -292,58 +292,44 @@ static int qcom_icc_bw_aggregate(struct icc_node *node, u32 tag, u32 avg_bw,
}
/**
* qcom_icc_bus_aggregate - aggregate bandwidth by traversing all nodes
* qcom_icc_bus_aggregate - calculate bus clock rates by traversing all nodes
* @provider: generic interconnect provider
* @agg_avg: an array for aggregated average bandwidth of buckets
* @agg_peak: an array for aggregated peak bandwidth of buckets
* @max_agg_avg: pointer to max value of aggregated average bandwidth
* @agg_clk_rate: array containing the aggregated clock rates in kHz
*/
static void qcom_icc_bus_aggregate(struct icc_provider *provider,
u64 *agg_avg, u64 *agg_peak,
u64 *max_agg_avg)
static void qcom_icc_bus_aggregate(struct icc_provider *provider, u64 *agg_clk_rate)
{
struct icc_node *node;
u64 agg_avg_rate, agg_rate;
struct qcom_icc_node *qn;
u64 sum_avg[QCOM_SMD_RPM_STATE_NUM];
struct icc_node *node;
int i;
/* Initialise aggregate values */
for (i = 0; i < QCOM_SMD_RPM_STATE_NUM; i++) {
agg_avg[i] = 0;
agg_peak[i] = 0;
}
*max_agg_avg = 0;
/*
* Iterate nodes on the interconnect and aggregate bandwidth
* requests for every bucket.
* Iterate nodes on the provider, aggregate bandwidth requests for
* every bucket and convert them into bus clock rates.
*/
list_for_each_entry(node, &provider->nodes, node_list) {
qn = node->data;
for (i = 0; i < QCOM_SMD_RPM_STATE_NUM; i++) {
if (qn->channels)
sum_avg[i] = div_u64(qn->sum_avg[i], qn->channels);
agg_avg_rate = div_u64(qn->sum_avg[i], qn->channels);
else
sum_avg[i] = qn->sum_avg[i];
agg_avg[i] += sum_avg[i];
agg_peak[i] = max_t(u64, agg_peak[i], qn->max_peak[i]);
agg_avg_rate = qn->sum_avg[i];
agg_rate = max_t(u64, agg_avg_rate, qn->max_peak[i]);
do_div(agg_rate, qn->buswidth);
agg_clk_rate[i] = max_t(u64, agg_clk_rate[i], agg_rate);
}
}
/* Find maximum values across all buckets */
for (i = 0; i < QCOM_SMD_RPM_STATE_NUM; i++)
*max_agg_avg = max_t(u64, *max_agg_avg, agg_avg[i]);
}
static int qcom_icc_set(struct icc_node *src, struct icc_node *dst)
{
struct qcom_icc_provider *qp;
struct qcom_icc_node *src_qn = NULL, *dst_qn = NULL;
u64 agg_clk_rate[QCOM_SMD_RPM_STATE_NUM] = { 0 };
struct icc_provider *provider;
struct qcom_icc_provider *qp;
u64 active_rate, sleep_rate;
u64 agg_avg[QCOM_SMD_RPM_STATE_NUM], agg_peak[QCOM_SMD_RPM_STATE_NUM];
u64 max_agg_avg;
int ret;
src_qn = src->data;
@ -352,7 +338,9 @@ static int qcom_icc_set(struct icc_node *src, struct icc_node *dst)
provider = src->provider;
qp = to_qcom_provider(provider);
qcom_icc_bus_aggregate(provider, agg_avg, agg_peak, &max_agg_avg);
qcom_icc_bus_aggregate(provider, agg_clk_rate);
active_rate = agg_clk_rate[QCOM_SMD_RPM_ACTIVE_STATE];
sleep_rate = agg_clk_rate[QCOM_SMD_RPM_SLEEP_STATE];
ret = qcom_icc_rpm_set(src_qn, src_qn->sum_avg);
if (ret)
@ -368,15 +356,6 @@ static int qcom_icc_set(struct icc_node *src, struct icc_node *dst)
if (!qp->bus_clk_desc && !qp->bus_clk)
return 0;
/* Intentionally keep the rates in kHz as that's what RPM accepts */
active_rate = max(agg_avg[QCOM_SMD_RPM_ACTIVE_STATE],
agg_peak[QCOM_SMD_RPM_ACTIVE_STATE]);
do_div(active_rate, src_qn->buswidth);
sleep_rate = max(agg_avg[QCOM_SMD_RPM_SLEEP_STATE],
agg_peak[QCOM_SMD_RPM_SLEEP_STATE]);
do_div(sleep_rate, src_qn->buswidth);
/*
* Downstream checks whether the requested rate is zero, but it makes little sense
* to vote for a value that's below the lower threshold, so let's not do so.