Re: [PATCH v2 3/4] firmware: qcom: scm: introduce qcom_scm_clk class for clock management

[Bjorn Andersson]

On Fri, Jul 31, 2026 at 10:00:36AM +0200, Bartosz Golaszewski wrote:
> Define DEFINE_CLASS(qcom_scm_clk) that calls qcom_scm_clk_enable() on
> construction and automatically calls qcom_scm_clk_disable() at scope exit
> *if* the enable succeeded.
> 
> This allows us to convert all call sites to using
> CLASS(qcom_scm_clk, clk)() instead of the manual enable/check/disable
> pattern and to remove the associated goto labels.
> 
> Reviewed-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxxxxxxxx>
> Reviewed-by: Mukesh Ojha <mukesh.ojha@xxxxxxxxxxxxxxxx>
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxxxxxxxx>
> ---
>  drivers/firmware/qcom/qcom_scm.c | 89 +++++++++++++++-------------------------
>  1 file changed, 34 insertions(+), 55 deletions(-)
> 
> diff --git a/drivers/firmware/qcom/qcom_scm.c b/drivers/firmware/qcom/qcom_scm.c
> index 10c79d2e59a14af0532c515d332f65bdfea05621..bb213f64703a7adb9ce413ec00524a7d0a1d3856 100644
> --- a/drivers/firmware/qcom/qcom_scm.c
> +++ b/drivers/firmware/qcom/qcom_scm.c
> @@ -209,6 +209,9 @@ static void qcom_scm_clk_disable(void)
>  	clk_disable_unprepare(__scm->bus_clk);
>  }
>  
> +DEFINE_CLASS(qcom_scm_clk, int, if (!_T) qcom_scm_clk_disable(),
> +	     qcom_scm_clk_enable(), void)
> +
>  static int qcom_scm_bw_enable(void)
>  {
>  	int ret = 0;
> @@ -509,13 +512,11 @@ static int qcom_scm_disable_sdi(void)
>  	};
>  	struct qcom_scm_res res;
>  
> -	ret = qcom_scm_clk_enable();
> -	if (ret)
> -		return ret;
> +	CLASS(qcom_scm_clk, clk)();

No matter how many times I read this line, it doesn't tell me "clocks
will be enabled from here to the end of the scope".

I don't like it.

Regards,
Bjorn

> +	if (clk)
> +		return clk;
>  	ret = qcom_scm_call(__scm->dev, &desc, &res);
>  
> -	qcom_scm_clk_disable();
> -
>  	return ret ? : res.result[0];
>  }
>  
> @@ -609,22 +610,19 @@ static int __qcom_scm_pas_init_image(struct device *dev, u32 pas_id,
>  	};
>  	int ret;
>  
> -	ret = qcom_scm_clk_enable();
> -	if (ret)
> -		return ret;
> +	CLASS(qcom_scm_clk, clk)();
> +	if (clk)
> +		return clk;
>  
>  	ret = qcom_scm_bw_enable();
>  	if (ret)
> -		goto disable_clk;
> +		return ret;
>  
>  	desc.args[1] = mdata_phys;
>  
>  	ret = qcom_scm_call(dev, &desc, res);
>  	qcom_scm_bw_disable();
>  
> -disable_clk:
> -	qcom_scm_clk_disable();
> -
>  	return ret;
>  }
>  
> @@ -734,20 +732,17 @@ static int __qcom_scm_pas_mem_setup(struct device *dev, u32 pas_id,
>  	};
>  	struct qcom_scm_res res;
>  
> -	ret = qcom_scm_clk_enable();
> -	if (ret)
> -		return ret;
> +	CLASS(qcom_scm_clk, clk)();
> +	if (clk)
> +		return clk;
>  
>  	ret = qcom_scm_bw_enable();
>  	if (ret)
> -		goto disable_clk;
> +		return ret;
>  
>  	ret = qcom_scm_call(dev, &desc, &res);
>  	qcom_scm_bw_disable();
>  
> -disable_clk:
> -	qcom_scm_clk_disable();
> -
>  	return ret ? : res.result[0];
>  }
>  
> @@ -819,13 +814,13 @@ static void *__qcom_scm_pas_get_rsc_table2(struct device *dev,
>  	void *tbl_ptr;
>  	int ret;
>  
> -	ret = qcom_scm_clk_enable();
> -	if (ret)
> -		return ERR_PTR(ret);
> +	CLASS(qcom_scm_clk, clk)();
> +	if (clk)
> +		return ERR_PTR(clk);
>  
>  	ret = qcom_scm_bw_enable();
>  	if (ret)
> -		goto disable_clk;
> +		return ERR_PTR(ret);
>  
>  	/*
>  	 * TrustZone can not accept buffer as NULL value as argument hence,
> @@ -872,9 +867,6 @@ static void *__qcom_scm_pas_get_rsc_table2(struct device *dev,
>  disable_scm_bw:
>  	qcom_scm_bw_disable();
>  
> -disable_clk:
> -	qcom_scm_clk_disable();
> -
>  	return ret ? ERR_PTR(ret) : tbl_ptr;
>  }
>  
> @@ -902,20 +894,17 @@ static int __qcom_scm_pas_auth_and_reset(struct device *dev, u32 pas_id)
>  	};
>  	struct qcom_scm_res res;
>  
> -	ret = qcom_scm_clk_enable();
> -	if (ret)
> -		return ret;
> +	CLASS(qcom_scm_clk, clk)();
> +	if (clk)
> +		return clk;
>  
>  	ret = qcom_scm_bw_enable();
>  	if (ret)
> -		goto disable_clk;
> +		return ret;
>  
>  	ret = qcom_scm_call(dev, &desc, &res);
>  	qcom_scm_bw_disable();
>  
> -disable_clk:
> -	qcom_scm_clk_disable();
> -
>  	return ret ? : res.result[0];
>  }
>  
> @@ -997,20 +986,17 @@ static int __qcom_scm_pas_shutdown(struct device *dev, u32 pas_id)
>  	};
>  	struct qcom_scm_res res;
>  
> -	ret = qcom_scm_clk_enable();
> -	if (ret)
> -		return ret;
> +	CLASS(qcom_scm_clk, clk)();
> +	if (clk)
> +		return clk;
>  
>  	ret = qcom_scm_bw_enable();
>  	if (ret)
> -		goto disable_clk;
> +		return ret;
>  
>  	ret = qcom_scm_call(dev, &desc, &res);
>  	qcom_scm_bw_disable();
>  
> -disable_clk:
> -	qcom_scm_clk_disable();
> -
>  	return ret ? : res.result[0];
>  }
>  
> @@ -1780,18 +1766,13 @@ EXPORT_SYMBOL_GPL(qcom_scm_import_ice_key);
>   */
>  bool qcom_scm_hdcp_available(void)
>  {
> -	bool avail;
> -	int ret = qcom_scm_clk_enable();
> +	CLASS(qcom_scm_clk, clk)();
>  
> -	if (ret)
> -		return ret;
> -
> -	avail = __qcom_scm_is_call_available(__scm->dev, QCOM_SCM_SVC_HDCP,
> -						QCOM_SCM_HDCP_INVOKE);
> -
> -	qcom_scm_clk_disable();
> +	if (clk)
> +		return false;
>  
> -	return avail;
> +	return __qcom_scm_is_call_available(__scm->dev, QCOM_SCM_SVC_HDCP,
> +					    QCOM_SCM_HDCP_INVOKE);
>  }
>  EXPORT_SYMBOL_GPL(qcom_scm_hdcp_available);
>  
> @@ -1829,15 +1810,13 @@ int qcom_scm_hdcp_req(struct qcom_scm_hdcp_req *req, u32 req_cnt, u32 *resp)
>  	if (req_cnt > QCOM_SCM_HDCP_MAX_REQ_CNT)
>  		return -ERANGE;
>  
> -	ret = qcom_scm_clk_enable();
> -	if (ret)
> -		return ret;
> +	CLASS(qcom_scm_clk, clk)();
> +	if (clk)
> +		return clk;
>  
>  	ret = qcom_scm_call(__scm->dev, &desc, &res);
>  	*resp = res.result[0];
>  
> -	qcom_scm_clk_disable();
> -
>  	return ret;
>  }
>  EXPORT_SYMBOL_GPL(qcom_scm_hdcp_req);
> 
> -- 
> 2.47.3
>