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

[Mathieu Poirier]

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@xxxxxxxxxx>
> Cc: Mike Leach <mike.leach@xxxxxxxxxx>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
> ---
>  .../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.

> +	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@xxxxxxxxxx>

> +	{}
> +};
> +
> +static struct platform_driver etm4_platform_driver = {
> +	.probe		= etm4_probe_platform_dev,
> +	.driver			= {
> +		.name			= "coresight-etm4x",
> +		.of_match_table		= etm_sysreg_match,
> +		.suppress_bind_attrs	= true,
> +	},
> +};
> +
>  static int __init etm4x_init(void)
>  {
>  	int ret;
> @@ -1793,10 +1824,19 @@ static int __init etm4x_init(void)
>  
>  	ret = amba_driver_register(&etm4x_amba_driver);
>  	if (ret) {
> -		pr_err("Error registering etm4x driver\n");
> -		etm4_pm_clear();
> +		pr_err("Error registering etm4x AMBA driver\n");
> +		goto clear_pm;
>  	}
>  
> +	ret = platform_driver_register(&etm4_platform_driver);
> +	if (!ret)
> +		return 0;
> +
> +	pr_err("Error registering etm4x platform driver\n");
> +	amba_driver_unregister(&etm4x_amba_driver);
> +
> +clear_pm:
> +	etm4_pm_clear();
>  	return ret;
>  }
>  
> -- 
> 2.24.1
>