linux-kernel - Re: [PATCH v12 4/9] firmware: qcom: scm: Rework dload mode availability check

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Date: Sat, 2 Mar 2024 13:16:31 -0600
From: Bjorn Andersson <andersson@...nel.org>
To: Mukesh Ojha <quic_mojha@...cinc.com>
Cc: konrad.dybcio@...aro.org, linux-arm-msm@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linus.walleij@...aro.org, linux-gpio@...r.kernel.org, 
	Elliot Berman <quic_eberman@...cinc.com>
Subject: Re: [PATCH v12 4/9] firmware: qcom: scm: Rework dload mode
 availability check

On Tue, Feb 27, 2024 at 09:23:03PM +0530, Mukesh Ojha wrote:
> QCOM_SCM_BOOT_SET_DLOAD_MODE was only valid for very older
> target and firmware and for recent targets there is dload
> mode tcsr registers available to set the download mode.
> 

I presume this implies that it will always return false, so what's the
actual problem with that? Presumably you want this because it takes
unnecessary time to make that call, if so please say so.


Content of the patch looks good.

Regards,
Bjorn

> So, it is better to keep it as fallback check instead of
> checking its availability and failing it always.
> 
> Signed-off-by: Mukesh Ojha <quic_mojha@...cinc.com>
> Reviewed-by: Elliot Berman <quic_eberman@...cinc.com>
> ---
>  drivers/firmware/qcom/qcom_scm.c | 12 +++++-------
>  1 file changed, 5 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/firmware/qcom/qcom_scm.c b/drivers/firmware/qcom/qcom_scm.c
> index bd6bfdf2d828..3fd89cddba3b 100644
> --- a/drivers/firmware/qcom/qcom_scm.c
> +++ b/drivers/firmware/qcom/qcom_scm.c
> @@ -540,18 +540,16 @@ static int __qcom_scm_set_dload_mode(struct device *dev, bool enable)
>  static void qcom_scm_set_download_mode(bool enable)
>  {
>  	u32 val = enable ? QCOM_DLOAD_FULLDUMP : QCOM_DLOAD_NODUMP;
> -	bool avail;
>  	int ret = 0;
>  
> -	avail = __qcom_scm_is_call_available(__scm->dev,
> -					     QCOM_SCM_SVC_BOOT,
> -					     QCOM_SCM_BOOT_SET_DLOAD_MODE);
> -	if (avail) {
> -		ret = __qcom_scm_set_dload_mode(__scm->dev, enable);
> -	} else if (__scm->dload_mode_addr) {
> +	if (__scm->dload_mode_addr) {
>  		ret = qcom_scm_io_rmw(__scm->dload_mode_addr,
>  				      QCOM_DLOAD_MASK,
>  				      FIELD_PREP(QCOM_DLOAD_MASK, val));
> +	} else if (__qcom_scm_is_call_available(__scm->dev,
> +						QCOM_SCM_SVC_BOOT,
> +						QCOM_SCM_BOOT_SET_DLOAD_MODE)) {
> +		ret = __qcom_scm_set_dload_mode(__scm->dev, enable);
>  	} else {
>  		dev_err(__scm->dev,
>  			"No available mechanism for setting download mode\n");
> -- 
> 2.43.0.254.ga26002b62827
>