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

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Date:   Tue, 8 Mar 2022 01:48:34 +0200
From:   Georgi Djakov <djakov@...nel.org>
To:     Bjorn Andersson <bjorn.andersson@...aro.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 8.03.22 0:42, Bjorn Andersson wrote:
> 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?

Right, it's fine then. Sorry for the noise.

BR,
Georgi

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