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Message-ID: <8139e102-677d-6850-b1c3-7a35e0e36904@nvidia.com>
Date:   Tue, 28 Mar 2023 18:00:32 +0530
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Subject: Re: [Patch v4 03/10] memory: tegra: add interconnect support for DRAM
 scaling in Tegra234
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To:     Thierry Reding <thierry.reding@gmail.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
CC:     <treding@nvidia.com>, <dmitry.osipenko@collabora.com>,
        <viresh.kumar@linaro.org>, <rafael@kernel.org>,
        <jonathanh@nvidia.com>, <robh+dt@kernel.org>,
        <lpieralisi@kernel.org>, <linux-kernel@vger.kernel.org>,
        <linux-tegra@vger.kernel.org>, <linux-pm@vger.kernel.org>,
        <devicetree@vger.kernel.org>, <linux-pci@vger.kernel.org>,
        <mmaddireddy@nvidia.com>, <kw@linux.com>, <bhelgaas@google.com>,
        <vidyas@nvidia.com>, <sanjayc@nvidia.com>, <ksitaraman@nvidia.com>,
        <ishah@nvidia.com>, <bbasu@nvidia.com>,
        Sumit Gupta <sumitg@nvidia.com>
References: <20230327161426.32639-1-sumitg@nvidia.com>
 <20230327161426.32639-4-sumitg@nvidia.com>
 <8b04a266-20eb-f1c1-278f-764b1b06b78b@linaro.org> <ZCLJ895gHPXQE+Lz@orome>
From:   Sumit Gupta <sumitg@nvidia.com>
In-Reply-To: <ZCLJ895gHPXQE+Lz@orome>
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On 28/03/23 16:35, Thierry Reding wrote:
> On Tue, Mar 28, 2023 at 09:31:58AM +0200, Krzysztof Kozlowski wrote:
>> On 27/03/2023 18:14, Sumit Gupta wrote:
> [...]
>>> diff --git a/drivers/memory/tegra/tegra186-emc.c b/drivers/memory/tegra/tegra186-emc.c
> [...]
>>> @@ -158,6 +260,9 @@ static int tegra186_emc_probe(struct platform_device *pdev)
>>>   	if (!emc)
>>>   		return -ENOMEM;
>>>   
>>> +	platform_set_drvdata(pdev, emc);
>>> +	emc->dev = &pdev->dev;
>>
>> This patch looks like stiched from two or more patches... emc->dev does
>> not look like new member of emc, thus why do you set in exisitng
>> function in this patch? Why it wasn't needed before?
> 
> This looks like it may be leftover from some development. These two
> lines exist in this driver a few lines further down. Either one pair
> should be removed. I don't see why this would need to be moved, so
> probably the above additions can just be dropped.
> 
> Thierry
> 
Yes, sorry i was left over. Will remove this.
Thank you for catching.

>>>   	emc->bpmp = tegra_bpmp_get(&pdev->dev);
>>>   	if (IS_ERR(emc->bpmp))
>>>   		return dev_err_probe(&pdev->dev, PTR_ERR(emc->bpmp), "failed to get BPMP\n");
>>> @@ -236,6 +341,25 @@ static int tegra186_emc_probe(struct platform_device *pdev)
>>>   	debugfs_create_file("max_rate", S_IRUGO | S_IWUSR, emc->debugfs.root,
>>>   			    emc, &tegra186_emc_debug_max_rate_fops);
>>>   
>>> +	mc = dev_get_drvdata(emc->dev->parent);
>>> +	if (mc && mc->soc->icc_ops) {
>>> +		/*
>>> +		 * Initialize the ICC even if BPMP-FW doesn't support 'MRQ_BWMGR_INT'.
>>> +		 * Use the flag 'mc->bwmgr_mrq_supported' within MC driver and return
>>> +		 * EINVAL instead of passing the request to BPMP-FW later when the BW
>>> +		 * request is made by client with 'icc_set_bw()' call.
>>> +		 */
>>> +		err = tegra_emc_interconnect_init(emc);
>>> +		if (err)
>>> +			goto put_bpmp;
>>> +
>>> +		if (tegra_bpmp_mrq_is_supported(emc->bpmp, MRQ_BWMGR_INT))
>>> +			mc->bwmgr_mrq_supported = true;
>>> +		else
>>> +
>>
>> Drop blank line.
>>
Ok.

>>> +			dev_info(&pdev->dev, "MRQ_BWMGR_INT not present\n");
>>
>> And what user is supposed to do with this? Either make it descriptive or
>> drop.
> 
> Agreed. I think we can just drop this. If the intention was to provide a
> quick way for people to detect whether BWMGR is available or not, using
> something from sysfs/debugfs would be preferable.
> 
> Thierry

Sure, will drop this.

Thank you,
Sumit Gupta