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

Mathieu Poirier
2020-08-17T16:40:41Z

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

> };
>
> /*
> --
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