linux-kernel - Re: [PATCH v10 19/24] coresight: cti: don't disable ect device if it's not enabled

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Date:   Mon, 14 Sep 2020 12:07:32 -0600
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     Tingwei Zhang <tingwei@...eaurora.org>
Cc:     Suzuki K Poulose <suzuki.poulose@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Mike Leach <mike.leach@...aro.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Leo Yan <leo.yan@...aro.org>,
        Randy Dunlap <rdunlap@...radead.org>,
        Russell King <linux@...linux.org.uk>,
        Kim Phillips <kim.phillips@....com>,
        Mian Yousaf Kaukab <ykaukab@...e.de>, tsoni@...eaurora.org,
        Sai Prakash Ranjan <saiprakash.ranjan@...eaurora.org>,
        Mao Jinlong <jinlmao@...eaurora.org>,
        coresight@...ts.linaro.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v10 19/24] coresight: cti: don't disable ect device if
 it's not enabled

On Fri, Aug 21, 2020 at 11:44:40AM +0800, Tingwei Zhang wrote:
> If associated ect device is not enabled at first place, disable
> routine should not be called. Add ect_enabled flag to check whether
> ect device is enabled. Fix the issue in below case.  Ect device is
> not available when associated coresight device enabled and the
> association is established after coresight device is enabled.
> 
> Signed-off-by: Mike Leach <mike.leach@...aro.org>
> Signed-off-by: Tingwei Zhang <tingwei@...eaurora.org>
> ---

Reviewed-by: Mathieu Poirier <mathieu.poirier@...aro.org>

>  drivers/hwtracing/coresight/coresight.c | 11 ++++++++---
>  include/linux/coresight.h               |  1 +
>  2 files changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
> index 6c09be15d60c..d354fd57474e 100644
> --- a/drivers/hwtracing/coresight/coresight.c
> +++ b/drivers/hwtracing/coresight/coresight.c
> @@ -244,13 +244,18 @@ coresight_control_assoc_ectdev(struct coresight_device *csdev, bool enable)
>  
>  	if (!ect_csdev)
>  		return 0;
> +	if ((!ect_ops(ect_csdev)->enable) || (!ect_ops(ect_csdev)->disable))
> +		return 0;
>  
>  	if (enable) {
> -		if (ect_ops(ect_csdev)->enable)
> -			ect_ret = ect_ops(ect_csdev)->enable(ect_csdev);
> +		ect_ret = ect_ops(ect_csdev)->enable(ect_csdev);
> +		if (!ect_ret)
> +			csdev->ect_enabled = true;
>  	} else {
> -		if (ect_ops(ect_csdev)->disable)
> +		if (csdev->ect_enabled) {
>  			ect_ret = ect_ops(ect_csdev)->disable(ect_csdev);
> +			csdev->ect_enabled = false;
> +		}
>  	}
>  
>  	/* output warning if ECT enable is preventing trace operation */
> diff --git a/include/linux/coresight.h b/include/linux/coresight.h
> index 3bb738f9a326..7d3c87e5b97c 100644
> --- a/include/linux/coresight.h
> +++ b/include/linux/coresight.h
> @@ -208,6 +208,7 @@ struct coresight_device {
>  	/* sysfs links between components */
>  	int nr_links;
>  	bool has_conns_grp;
> +	bool ect_enabled; /* true only if associated ect device is enabled */
>  };
>  
>  /*
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
>