linux-kernel - Re: [PATCH v8 5/8] interconnect: qcom: rpm: Handle interface clocks

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Date:   Thu, 18 May 2023 18:59:46 +0300
From:   Georgi Djakov <djakov@...nel.org>
To:     Konrad Dybcio <konrad.dybcio@...aro.org>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Cc:     Bryan O'Donoghue <bryan.odonoghue@...aro.org>,
        linux-arm-msm@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Marijn Suijten <marijn.suijten@...ainline.org>
Subject: Re: [PATCH v8 5/8] interconnect: qcom: rpm: Handle interface clocks

Hi Konrad,
Thanks for re-spinning the patches!

On 7.04.23 23:14, Konrad Dybcio wrote:
> Some (but not all) providers (or their specific nodes) require
> specific clocks to be turned on before they can be accessed. Failure
> to ensure that results in a seemingly random system crash (which
> would usually happen at boot with the interconnect driver built-in),
> resulting in the platform not booting up properly.
> 
> Limit the number of bus_clocks to 2 (which is the maximum that SMD
> RPM interconnect supports anyway) and handle non-scaling clocks
> separately. Update MSM8996 and SDM660 drivers to make sure they do
> not regress with this change.
> 
> This unfortunately has to be done in one patch to prevent either
> compile errors or broken bisect.
> 
> Signed-off-by: Konrad Dybcio <konrad.dybcio@...aro.org>
> ---
>   drivers/interconnect/qcom/icc-rpm.c | 40 ++++++++++++++++++++++++++++---------
>   drivers/interconnect/qcom/icc-rpm.h | 14 +++++++++++--
>   drivers/interconnect/qcom/msm8996.c | 22 +++++++++-----------
>   drivers/interconnect/qcom/sdm660.c  | 16 ++++++---------
>   4 files changed, 58 insertions(+), 34 deletions(-)
> 
> diff --git a/drivers/interconnect/qcom/icc-rpm.c b/drivers/interconnect/qcom/icc-rpm.c
> index d79e508cb717..419b2122bebd 100644
> --- a/drivers/interconnect/qcom/icc-rpm.c
> +++ b/drivers/interconnect/qcom/icc-rpm.c
> @@ -424,21 +424,20 @@ int qnoc_probe(struct platform_device *pdev)
>   	qnodes = desc->nodes;
>   	num_nodes = desc->num_nodes;
>   
> -	if (desc->num_bus_clocks) {
> -		cds = desc->bus_clocks;
> -		cd_num = desc->num_bus_clocks;
> +	if (desc->num_intf_clocks) {
> +		cds = desc->intf_clocks;
> +		cd_num = desc->num_intf_clocks;
>   	} else {
> -		cds = bus_clocks;
> -		cd_num = ARRAY_SIZE(bus_clocks);
> +		/* 0 intf clocks is perfectly fine */
> +		cd_num = 0;
>   	}
>   
> -	qp = devm_kzalloc(dev, struct_size(qp, bus_clks, cd_num), GFP_KERNEL);
> +	qp = devm_kzalloc(dev, sizeof(*qp), GFP_KERNEL);
>   	if (!qp)
>   		return -ENOMEM;
>   
> -	qp->bus_clk_rate = devm_kcalloc(dev, cd_num, sizeof(*qp->bus_clk_rate),
> -					GFP_KERNEL);
> -	if (!qp->bus_clk_rate)
> +	qp->intf_clks = devm_kzalloc(dev, sizeof(qp->intf_clks), GFP_KERNEL);
> +	if (!qp->intf_clks)
>   		return -ENOMEM;
>   
>   	data = devm_kzalloc(dev, struct_size(data, nodes, num_nodes),
> @@ -446,6 +445,18 @@ int qnoc_probe(struct platform_device *pdev)
>   	if (!data)
>   		return -ENOMEM;
>   
> +	qp->num_intf_clks = cd_num;
> +	for (i = 0; i < cd_num; i++)
> +		qp->intf_clks[i].id = cds[i];

Sadly, this is introducing a superfluous compiler warning, which is a bit annoying.
Could you please add some initialization to silence it and re-send just this patch.

drivers/interconnect/qcom/icc-rpm.c: In function ‘qnoc_probe’:
drivers/interconnect/qcom/icc-rpm.c:450:28: warning: ‘cds’ may be used uninitialized in this 
function [-Wmaybe-uninitialized]
   450 |   qp->intf_clks[i].id = cds[i];
       |                         ~~~^~~

BR,
Georgi