linux-kernel - Re: [PATCH] remoteproc: qcom: q6v5: Add interconnect path proxy vote

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Date:   Mon, 7 Mar 2022 14:42:53 -0800
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     Georgi Djakov <djakov@...nel.org>
Cc:     Sibi Sankar <quic_sibis@...cinc.com>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        linux-arm-msm@...r.kernel.org, linux-remoteproc@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] remoteproc: qcom: q6v5: Add interconnect path proxy vote

On Mon 07 Mar 10:35 PST 2022, Georgi Djakov wrote:

> 
> On 25.02.22 5:32, Bjorn Andersson wrote:
> > Many remoteproc instances requires that Linux casts a proxy vote for an
> > interconnect path during boot, until they can do it themselves. Add
> > support for voting for a single path.
> > 
> > As this is a shared problem between both PAS and MSS drivers, the path
> > is acquired and votes casted from the common helper code.
> > 
> > Signed-off-by: Bjorn Andersson <bjorn.andersson@...aro.org>
> > ---
> > 
> > Sibi posted recently a patch to add interconnect votes from the modem driver,
> > today I needed the same feature for one of the PAS remoteprocs. After
> > essentially duplicating Sibi's patch I realized that it doesn't look too bad to
> > put this in the common Q6V5 code.
> > 
> > The main difference is that this would be messy if we need to support multiple
> > paths, so we probably would have to push it out to the individual drivers at
> > that point.
> > 
> > Sibi's patch can be found here.
> > https://lore.kernel.org/all/1644813252-12897-3-git-send-email-quic_sibis@quicinc.com/
> > 
> > 
> > This makes the implementation pick up one path, relevant DT bindings would
> > still need to be updated in order be allowed to this in the DeviceTree files.
> > 
> >   drivers/remoteproc/qcom_q6v5.c | 21 ++++++++++++++++++++-
> >   drivers/remoteproc/qcom_q6v5.h |  3 +++
> >   2 files changed, 23 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/remoteproc/qcom_q6v5.c b/drivers/remoteproc/qcom_q6v5.c
> > index 442a388f8102..5280ec9b5449 100644
> > --- a/drivers/remoteproc/qcom_q6v5.c
> > +++ b/drivers/remoteproc/qcom_q6v5.c
> > @@ -8,6 +8,7 @@
> >    */
> >   #include <linux/kernel.h>
> >   #include <linux/platform_device.h>
> > +#include <linux/interconnect.h>
> >   #include <linux/interrupt.h>
> >   #include <linux/module.h>
> >   #include <linux/soc/qcom/qcom_aoss.h>
> > @@ -51,9 +52,17 @@ int qcom_q6v5_prepare(struct qcom_q6v5 *q6v5)
> >   {
> >   	int ret;
> > +	ret = icc_set_bw(q6v5->path, 0, UINT_MAX);
> > +	if (ret < 0) {
> > +		dev_err(q6v5->dev, "failed to set bandwidth request\n");
> > +		return ret;
> > +	}
> > +
> >   	ret = q6v5_load_state_toggle(q6v5, true);
> > -	if (ret)
> > +	if (ret) {
> > +		icc_set_bw(q6v5->path, 0, 0);
> >   		return ret;
> > +	}
> >   	reinit_completion(&q6v5->start_done);
> >   	reinit_completion(&q6v5->stop_done);
> > @@ -78,6 +87,9 @@ int qcom_q6v5_unprepare(struct qcom_q6v5 *q6v5)
> >   	disable_irq(q6v5->handover_irq);
> >   	q6v5_load_state_toggle(q6v5, false);
> > +	/* Disable interconnect vote, in case handover never happened */
> > +	icc_set_bw(q6v5->path, 0, 0);
> > +
> >   	return !q6v5->handover_issued;
> >   }
> >   EXPORT_SYMBOL_GPL(qcom_q6v5_unprepare);
> > @@ -160,6 +172,8 @@ static irqreturn_t q6v5_handover_interrupt(int irq, void *data)
> >   	if (q6v5->handover)
> >   		q6v5->handover(q6v5);
> > +	icc_set_bw(q6v5->path, 0, 0);
> > +
> >   	q6v5->handover_issued = true;
> >   	return IRQ_HANDLED;
> > @@ -332,6 +346,11 @@ int qcom_q6v5_init(struct qcom_q6v5 *q6v5, struct platform_device *pdev,
> >   		return load_state ? -ENOMEM : -EINVAL;
> >   	}
> > +	q6v5->path = devm_of_icc_get(&pdev->dev, NULL);
> > +	if (IS_ERR(q6v5->path))
> > +		return dev_err_probe(&pdev->dev, PTR_ERR(q6v5->path),
> > +				     "failed to acquire interconnect path\n");
> > +
> >   	return 0;
> >   }
> >   EXPORT_SYMBOL_GPL(qcom_q6v5_init);
> 
> Probably we should also call icc_put(q6v5->path) in qcom_q6v5_deinit().
> 

The use of devm_of_icc_get() should take care of that for us. Or am I
missing something?

> Reviewed-by: Georgi Djakov <djakov@...nel.org>
> 

Thanks,
Bjorn