linux-kernel - Re: [PATCH V2 2/5] coresight: etm4x: Drop iomem 'base' argument from etm4

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Date:   Tue, 16 May 2023 16:41:48 +0530
From:   Anshuman Khandual <anshuman.khandual@....com>
To:     James Clark <james.clark@....com>,
        linux-arm-kernel@...ts.infradead.org, coresight@...ts.linaro.org,
        suzuki.poulose@....com
Cc:     scclevenger@...amperecomputing.com,
        Rob Herring <robh+dt@...nel.org>,
        Frank Rowand <frowand.list@...il.com>,
        Russell King <linux@...linux.org.uk>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Len Brown <lenb@...nel.org>,
        Sudeep Holla <sudeep.holla@....com>,
        Lorenzo Pieralisi <lpieralisi@...nel.org>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        Mike Leach <mike.leach@...aro.org>, devicetree@...r.kernel.org,
        linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH V2 2/5] coresight: etm4x: Drop iomem 'base' argument from
 etm4_probe()



On 4/4/23 20:52, James Clark wrote:
> 
> On 27/03/2023 06:05, Anshuman Khandual wrote:
>> 'struct etm4_drvdata' itself can carry the base address before etm4_probe()
>> gets called. Just drop that redundant argument from etm4_probe().
>>
>> Cc: Mathieu Poirier <mathieu.poirier@...aro.org>
>> Cc: Suzuki K Poulose <suzuki.poulose@....com>
>> Cc: Mike Leach <mike.leach@...aro.org>
>> Cc: Leo Yan <leo.yan@...aro.org>
>> Cc: coresight@...ts.linaro.org
>> Cc: linux-arm-kernel@...ts.infradead.org
>> Cc: linux-kernel@...r.kernel.org
>> Signed-off-by: Anshuman Khandual <anshuman.khandual@....com>
>> ---
>>  drivers/hwtracing/coresight/coresight-etm4x-core.c | 10 +++++-----
>>  1 file changed, 5 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
>> index 10119c223fbe..5d77571a8df9 100644
>> --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
>> +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
>> @@ -2048,7 +2048,7 @@ static int etm4_add_coresight_dev(struct etm4_init_arg *init_arg)
>>  	return 0;
>>  }
>>  
>> -static int etm4_probe(struct device *dev, void __iomem *base, u32 etm_pid)
>> +static int etm4_probe(struct device *dev, u32 etm_pid)
>>  {
>>  	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev);
>>  	struct csdev_access access = { 0 };
>> @@ -2069,8 +2069,6 @@ static int etm4_probe(struct device *dev, void __iomem *base, u32 etm_pid)
>>  			return -ENOMEM;
>>  	}
>>  
>> -	drvdata->base = base;
>> -
>>  	spin_lock_init(&drvdata->spinlock);
>>  
>>  	drvdata->cpu = coresight_get_cpu(dev);
>> @@ -2124,8 +2122,9 @@ static int etm4_probe_amba(struct amba_device *adev, const struct amba_id *id)
>>  	if (!drvdata)
>>  		return -ENOMEM;
>>  
>> +	drvdata->base = base;
>>  	dev_set_drvdata(dev, drvdata);
>> -	ret = etm4_probe(dev, base, id->id);
>> +	ret = etm4_probe(dev, id->id);
>>  	if (!ret)
>>  		pm_runtime_put(&adev->dev);
>>  
>> @@ -2141,6 +2140,7 @@ static int etm4_probe_platform_dev(struct platform_device *pdev)
>>  	if (!drvdata)
>>  		return -ENOMEM;
>>  
>> +	drvdata->base = NULL;
> Very minor point, drvdata is zero alloced so it doesn't make sense to
> zero this field but not the others. It's harmless, but it might imply
> something and confuse someone.

Just to keep changes to both call sites of etm4_probe() similar i.e
etm4_probe()'s 'base' argument being pre-assigned as drvdata->base,
let's keep the NULL assignment above unchanged.

> 
> Either way:
> Reviewed-by: James Clark <james.clark@....com>
>