Re: [PATCH v8 19/24] coresight: cti: don't disable ect device if it's not enabled

[Mathieu Poirier <mathieu.poirier@linaro.org>]

On Fri, Aug 07, 2020 at 07:11:48PM +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@linaro.org>
> Signed-off-by: Tingwei Zhang <tingwei@codeaurora.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 d066411aa794..27ad8317e3cf 100644
> --- a/drivers/hwtracing/coresight/coresight.c
> +++ b/drivers/hwtracing/coresight/coresight.c
> @@ -245,13 +245,18 @@ 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 */

We have cti_config::enable_req_count and cti_config::hw_enabled, both used in
cti_enable_hw() and cti_disable_hw().  I would have thought they'd be sufficient
to address the counting problems.  If they are not I would much rather see a
solution confined to the cti driver than in the core itself. 

Thanks,
Mathieu

>  };
>  
>  /*
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
> 

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