linux-kernel - Re: [PATCH v3 25/26] coresight: etm4x: Add support for sysreg only devices

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Message-ID: <9566bf8c-3e05-7a81-d487-647a057ae4f1@arm.com>
Date:   Tue, 10 Nov 2020 10:50:36 +0000
From:   Suzuki K Poulose <suzuki.poulose@....com>
To:     Mathieu Poirier <mathieu.poirier@...aro.org>
Cc:     linux-arm-kernel@...ts.infradead.org, mike.leach@...aro.org,
        coresight@...ts.linaro.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 25/26] coresight: etm4x: Add support for sysreg only
 devices

On 11/9/20 8:46 PM, Mathieu Poirier wrote:
> On Wed, Oct 28, 2020 at 10:09:44PM +0000, Suzuki K Poulose wrote:
>> Add support for devices with system instruction access only.
>> They don't have a memory mapped interface and thus are not
>> AMBA devices.
>>
>> Cc: Mathieu Poirier <mathieu.poirier@...aro.org>
>> Cc: Mike Leach <mike.leach@...aro.org>
>> Signed-off-by: Suzuki K Poulose <suzuki.poulose@....com>
>> ---
>>   .../coresight/coresight-etm4x-core.c          | 50 +++++++++++++++++--
>>   1 file changed, 45 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
>> index 25fab5513604..50a574228866 100644
>> --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
>> +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
>> @@ -26,6 +26,7 @@
>>   #include <linux/seq_file.h>
>>   #include <linux/uaccess.h>
>>   #include <linux/perf_event.h>
>> +#include <linux/platform_device.h>
>>   #include <linux/pm_runtime.h>
>>   #include <linux/property.h>
>>   #include <asm/sections.h>
>> @@ -1623,9 +1624,6 @@ static int etm4_probe(struct device *dev, void __iomem *base)
>>   			return -ENOMEM;
>>   	}
>>   
>> -	if (fwnode_property_present(dev_fwnode(dev), "qcom,skip-power-up"))
>> -		drvdata->skip_power_up = true;
>> -
>>   	drvdata->base = base;
>>   
>>   	spin_lock_init(&drvdata->spinlock);
>> @@ -1648,6 +1646,11 @@ static int etm4_probe(struct device *dev, void __iomem *base)
>>   	if (!drvdata->arch)
>>   		return -EINVAL;
>>   
>> +	/* Skip programming TRCPDCR for system instructions. */
> 
> It would be nice to mention that TRCPDCR is not available in system instruction
> mode.

Sure.

> 
>> +	if (!desc.access.io_mem ||
>> +	    fwnode_property_present(dev_fwnode(dev), "qcom,skip-power-up"))
>> +		drvdata->skip_power_up = true;
>> +
>>   	etm4_init_trace_id(drvdata);
>>   	etm4_set_default(&drvdata->config);
>>   
>> @@ -1706,6 +1709,20 @@ static int etm4_probe_amba(struct amba_device *adev, const struct amba_id *id)
>>   	return ret;
>>   }
>>   
>> +static int etm4_probe_platform_dev(struct platform_device *pdev)
>> +{
>> +	int ret;
>> +
>> +	pm_runtime_get_noresume(&pdev->dev);
>> +	pm_runtime_set_active(&pdev->dev);
>> +	pm_runtime_enable(&pdev->dev);
>> +
>> +	ret = etm4_probe(&pdev->dev, NULL);
>> +
>> +	pm_runtime_put(&pdev->dev);
>> +	return ret;
>> +}
>> +
>>   static struct amba_cs_uci_id uci_id_etm4[] = {
>>   	{
>>   		/*  ETMv4 UCI data */
>> @@ -1781,6 +1798,20 @@ static struct amba_driver etm4x_amba_driver = {
>>   	.id_table	= etm4_ids,
>>   };
>>   
>> +static const struct of_device_id etm_sysreg_match[] = {
> 
> s/etm_sysreg_match/etm4_sysreg_match
> 
>> +	{ .compatible	= "arm,coresight-etm-sysreg" },
> 
> See my comment in the next patch.
> 
> With the above:
> 
> Reviewed-by: Mathieu Poirier <mathieu.poirier@...aro.org>
> 

Thanks

Suzuki