linux-kernel - Re: [PATCH v2] firmware: qcom_scm: modify qcom_scm_set_download

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Date:   Sat, 18 Feb 2023 18:08:36 +0530
From:   Mukesh Ojha <quic_mojha@...cinc.com>
To:     Bjorn Andersson <andersson@...nel.org>
CC:     <agross@...nel.org>, <konrad.dybcio@...aro.org>,
        <linux-arm-msm@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] firmware: qcom_scm: modify
 qcom_scm_set_download_mode()



On 2/4/2023 12:32 AM, Bjorn Andersson wrote:
> On Fri, Feb 03, 2023 at 03:47:15PM +0530, Mukesh Ojha wrote:
>> Modify qcom_scm_set_download_mode() such that it can support
>> multiple modes. There is no functional change with this change.
>>
> 
> As Dmitry said, you argue for added flexibility, but doesn't provide a
> user of that flexibility. I will drop this patch from the queue for now.
> 
> Please include this together with the patch(es) that benefit from such
> flexibility.

Sure, will add this along with patches which benefit from this change.

> 
>> Signed-off-by: Mukesh Ojha <quic_mojha@...cinc.com>
>> ---
>> Changes in v2:
>>    - Stop changing legacy scm id for dload mode.
>>
>>   drivers/firmware/qcom_scm.c | 15 +++++++--------
>>   include/linux/qcom_scm.h    |  5 +++++
>>   2 files changed, 12 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
>> index cdbfe54..6245b97 100644
>> --- a/drivers/firmware/qcom_scm.c
>> +++ b/drivers/firmware/qcom_scm.c
>> @@ -400,7 +400,7 @@ int qcom_scm_set_remote_state(u32 state, u32 id)
>>   }
>>   EXPORT_SYMBOL(qcom_scm_set_remote_state);
>>   
>> -static int __qcom_scm_set_dload_mode(struct device *dev, bool enable)
>> +static int __qcom_scm_set_dload_mode(struct device *dev, enum qcom_download_mode mode)
>>   {
>>   	struct qcom_scm_desc desc = {
>>   		.svc = QCOM_SCM_SVC_BOOT,
>> @@ -410,12 +410,12 @@ static int __qcom_scm_set_dload_mode(struct device *dev, bool enable)
>>   		.owner = ARM_SMCCC_OWNER_SIP,
>>   	};
>>   
>> -	desc.args[1] = enable ? QCOM_SCM_BOOT_SET_DLOAD_MODE : 0;
>> +	desc.args[1] = mode ? QCOM_SCM_BOOT_SET_DLOAD_MODE : 0;
>>   
>>   	return qcom_scm_call_atomic(__scm->dev, &desc, NULL);
>>   }
>>   
>> -static void qcom_scm_set_download_mode(bool enable)
>> +static void qcom_scm_set_download_mode(enum qcom_download_mode mode)
>>   {
>>   	bool avail;
>>   	int ret = 0;
>> @@ -424,10 +424,9 @@ static void qcom_scm_set_download_mode(bool enable)
>>   					     QCOM_SCM_SVC_BOOT,
>>   					     QCOM_SCM_BOOT_SET_DLOAD_MODE);
>>   	if (avail) {
>> -		ret = __qcom_scm_set_dload_mode(__scm->dev, enable);
>> +		ret = __qcom_scm_set_dload_mode(__scm->dev, mode);
>>   	} else if (__scm->dload_mode_addr) {
>> -		ret = qcom_scm_io_writel(__scm->dload_mode_addr,
>> -				enable ? QCOM_SCM_BOOT_SET_DLOAD_MODE : 0);
>> +		ret = qcom_scm_io_writel(__scm->dload_mode_addr, mode);
>>   	} else {
>>   		dev_err(__scm->dev,
>>   			"No available mechanism for setting download mode\n");
>> @@ -1410,7 +1409,7 @@ static int qcom_scm_probe(struct platform_device *pdev)
>>   	 * disabled below by a clean shutdown/reboot.
>>   	 */
>>   	if (download_mode)
>> -		qcom_scm_set_download_mode(true);
>> +		qcom_scm_set_download_mode(QCOM_DOWNLOAD_FULLDUMP);
>>   
>>   	return 0;
>>   }
>> @@ -1419,7 +1418,7 @@ static void qcom_scm_shutdown(struct platform_device *pdev)
>>   {
>>   	/* Clean shutdown, disable download mode to allow normal restart */
>>   	if (download_mode)
> 
> PS. Wouldn't it make sense, if !download_mode to set NODUMP?

IMO, it does not need even a check, since our intention is to disable
download mode during reboot/restart.

-Mukesh
> 
> Regards,
> Bjorn
> 
>> -		qcom_scm_set_download_mode(false);
>> +		qcom_scm_set_download_mode(QCOM_DOWNLOAD_NODUMP);
>>   }
>>   
>>   static const struct of_device_id qcom_scm_dt_match[] = {
>> diff --git a/include/linux/qcom_scm.h b/include/linux/qcom_scm.h
>> index f833564..f9bc84e 100644
>> --- a/include/linux/qcom_scm.h
>> +++ b/include/linux/qcom_scm.h
>> @@ -14,6 +14,11 @@
>>   #define QCOM_SCM_CPU_PWR_DOWN_L2_OFF	0x1
>>   #define QCOM_SCM_HDCP_MAX_REQ_CNT	5
>>   
>> +enum qcom_download_mode {
>> +	QCOM_DOWNLOAD_NODUMP    = 0x00,
>> +	QCOM_DOWNLOAD_FULLDUMP  = 0x10,
>> +};
>> +
>>   struct qcom_scm_hdcp_req {
>>   	u32 addr;
>>   	u32 val;
>> -- 
>> 2.7.4
>>