[PATCH v4] coresight: fix missing error code when trace ID is invalid

[Leo Yan]

On Tue, May 12, 2026 at 09:56:07AM +0800, Jie Gan wrote:
> When coresight_path_assign_trace_id() cannot assign a valid trace ID,
> coresight_enable_sysfs() takes the err_path goto with ret still 0,
> returning success to the caller despite no trace session being started.
> 
> Change coresight_path_assign_trace_id() to return int, moving the
> IS_VALID_CS_TRACE_ID() check inside it so it returns -EINVAL on failure
> and 0 on success. Update both callers to propagate this return value
> directly instead of inspecting path->trace_id after the call.
> 
> Fixes: d87d76d823d1 ("Coresight: Allocate trace ID after building the path")
> Reviewed-by: James Clark <james.clark at linaro.org>
> Reviewed-by: Richard Cheng <icheng at nvidia.com>
> Signed-off-by: Jie Gan <jie.gan at oss.qualcomm.com>

Reviewed-by: Leo Yan <leo.yan at arm.com>