linux-kernel - Re: [PATCH v3 04/10] interconnect: qcom: icc-rpm: Check for node-specific rate coefficients

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Date:   Thu, 10 Aug 2023 09:26:21 +0200
From:   Stephan Gerhold <stephan@...hold.net>
To:     Konrad Dybcio <konrad.dybcio@...aro.org>
Cc:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Georgi Djakov <djakov@...nel.org>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Marijn Suijten <marijn.suijten@...ainline.org>,
        linux-arm-msm@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-clk@...r.kernel.org
Subject: Re: [PATCH v3 04/10] interconnect: qcom: icc-rpm: Check for
 node-specific rate coefficients

On Tue, Aug 08, 2023 at 01:43:35PM +0200, Konrad Dybcio wrote:
> Some nodes may have different coefficients than the general values for
> bus they're attached to. Check for that and use them if present. See
> [1], [2] for reference.
> 
> [1] https://github.com/sonyxperiadev/kernel/commit/7456d9779af9ad6bb9c7ee6f33d5c5a8d3648e24
> [2] https://github.com/artem/android_kernel_sony_msm8996/commit/bf7a8985dcaf0eab5bc2562d2d6775e7e29c0f30
> Signed-off-by: Konrad Dybcio <konrad.dybcio@...aro.org>
> ---
>  drivers/interconnect/qcom/icc-rpm.c | 14 ++++++++++----
>  drivers/interconnect/qcom/icc-rpm.h |  5 +++++
>  2 files changed, 15 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/interconnect/qcom/icc-rpm.c b/drivers/interconnect/qcom/icc-rpm.c
> index 1d3af4e9ead8..9c40314e03b5 100644
> --- a/drivers/interconnect/qcom/icc-rpm.c
> +++ b/drivers/interconnect/qcom/icc-rpm.c
> @@ -300,14 +300,14 @@ static u64 qcom_icc_calc_rate(struct qcom_icc_provider *qp, struct qcom_icc_node
>  	else
>  		agg_avg_rate = qn->sum_avg[ctx];
>  
> -	if (qp->ab_coeff) {
> -		agg_avg_rate = agg_avg_rate * qp->ab_coeff;
> +	if (qn->ab_coeff) {
> +		agg_avg_rate = agg_avg_rate * qn->ab_coeff;
>  		agg_avg_rate = div_u64(agg_avg_rate, 100);
>  	}
>  
> -	if (qp->ib_coeff) {
> +	if (qn->ib_coeff) {
>  		agg_peak_rate = qn->max_peak[ctx] * 100;
> -		agg_peak_rate = div_u64(qn->max_peak[ctx], qp->ib_coeff);
> +		agg_peak_rate = div_u64(qn->max_peak[ctx], qn->ib_coeff);
>  	} else {
>  		agg_peak_rate = qn->max_peak[ctx];
>  	}
> @@ -563,6 +563,12 @@ int qnoc_probe(struct platform_device *pdev)
>  	for (i = 0; i < num_nodes; i++) {
>  		size_t j;
>  
> +		if (!qnodes[i]->ab_coeff)
> +			qnodes[i]->ab_coeff = qp->ab_coeff;
> +
> +		if (!qnodes[i]->ib_coeff)
> +			qnodes[i]->ib_coeff = qp->ib_coeff;
> +
>  		node = icc_node_create(qnodes[i]->id);
>  		if (IS_ERR(node)) {
>  			ret = PTR_ERR(node);
> diff --git a/drivers/interconnect/qcom/icc-rpm.h b/drivers/interconnect/qcom/icc-rpm.h
> index f9ef16f570be..4abf99ce2690 100644
> --- a/drivers/interconnect/qcom/icc-rpm.h
> +++ b/drivers/interconnect/qcom/icc-rpm.h
> @@ -103,6 +103,9 @@ struct qcom_icc_qos {
>   * @mas_rpm_id:	RPM id for devices that are bus masters
>   * @slv_rpm_id:	RPM id for devices that are bus slaves
>   * @qos: NoC QoS setting parameters
> + * @ab_coeff: a percentage-based coefficient for compensating the AB calculations
> + * @ib_coeff: an inverse-percentage-based coefficient for compensating the IB calculations
> + * @bus_clk_rate: a pointer to an array containing bus clock rates in Hz

Nitpick: The doc comment needs to be moved to the earlier patch as well. :)

>   */
>  struct qcom_icc_node {
>  	unsigned char *name;
> @@ -117,6 +120,8 @@ struct qcom_icc_node {
>  	int mas_rpm_id;
>  	int slv_rpm_id;
>  	struct qcom_icc_qos qos;
> +	u16 ab_coeff;
> +	u16 ib_coeff;
>  	u32 bus_clk_rate[QCOM_SMD_RPM_STATE_NUM];
>  };
>  
> 
> -- 
> 2.41.0
>