linux-kernel - Re: [PATCH v17 03/12] power: reset: reboot-mode: Add support for 64 bit magic

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Message-ID: <16521e84-9da6-53a7-febe-9decb6970c06@oss.qualcomm.com>
Date: Mon, 10 Nov 2025 20:08:15 +0530
From: Shivendra Pratap <shivendra.pratap@....qualcomm.com>
To: Mukesh Ojha <mukesh.ojha@....qualcomm.com>
Cc: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Sebastian Reichel <sre@...nel.org>, Rob Herring <robh@...nel.org>,
        Sudeep Holla <sudeep.holla@....com>,
        Souvik Chakravarty <Souvik.Chakravarty@....com>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley
 <conor+dt@...nel.org>,
        Andy Yan <andy.yan@...k-chips.com>,
        Mark Rutland <mark.rutland@....com>,
        Lorenzo Pieralisi <lpieralisi@...nel.org>,
        Arnd Bergmann <arnd@...db.de>, Konrad Dybcio <konradybcio@...nel.org>,
        cros-qcom-dts-watchers@...omium.org, Vinod Koul <vkoul@...nel.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Florian Fainelli <florian.fainelli@...adcom.com>,
        Moritz Fischer <moritz.fischer@...us.com>,
        John Stultz <john.stultz@...aro.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>,
        Stephen Boyd <swboyd@...omium.org>,
        Andre Draszik
 <andre.draszik@...aro.org>,
        Kathiravan Thirumoorthy <kathiravan.thirumoorthy@....qualcomm.com>,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-arm-msm@...r.kernel.org,
        Elliot Berman <quic_eberman@...cinc.com>,
        Xin Liu <xin.liu@....qualcomm.com>,
        Srinivas Kandagatla <srini@...nel.org>,
        Umang Chheda <umang.chheda@....qualcomm.com>,
        Nirmesh Kumar Singh <nirmesh.singh@....qualcomm.com>
Subject: Re: [PATCH v17 03/12] power: reset: reboot-mode: Add support for 64
 bit magic



On 11/10/2025 7:15 PM, Mukesh Ojha wrote:
> On Sun, Nov 09, 2025 at 08:07:16PM +0530, Shivendra Pratap wrote:
>> Current reboot-mode supports a single 32-bit argument for any

[SNIP..]

>>  
>> -static int nvmem_reboot_mode_write(struct reboot_mode_driver *reboot,
>> -				    unsigned int magic)
>> +static int nvmem_reboot_mode_write(struct reboot_mode_driver *reboot, u64 magic)
>>  {
>> -	int ret;
>>  	struct nvmem_reboot_mode *nvmem_rbm;
>> +	u32 magic_32;
>> +	int ret;
>> +
>> +	if (magic > U32_MAX)
>> +		return -EINVAL;
> 
> 
> I believe, we need a comment in all the client driver.. 

Ack. Will add a comment.

> 
>> +
>> +	magic_32 = magic;
>>  
>>  	nvmem_rbm = container_of(reboot, struct nvmem_reboot_mode, reboot);
>>  
>> -	ret = nvmem_cell_write(nvmem_rbm->cell, &magic, sizeof(magic));
>> +	ret = nvmem_cell_write(nvmem_rbm->cell, &magic_32, sizeof(magic_32));
>>  	if (ret < 0)
>>  		dev_err(reboot->dev, "update reboot mode bits failed\n");
>>  
>> diff --git a/drivers/power/reset/qcom-pon.c b/drivers/power/reset/qcom-pon.c
>> index 7e108982a582e8243c5c806bd4a793646b87189f..d0ed9431a02313a7bbaa93743c16fa1ae713ddfe 100644
>> --- a/drivers/power/reset/qcom-pon.c
>> +++ b/drivers/power/reset/qcom-pon.c
>> @@ -27,17 +27,22 @@ struct qcom_pon {
>>  	long reason_shift;
>>  };
>>  
>> -static int qcom_pon_reboot_mode_write(struct reboot_mode_driver *reboot,
>> -				    unsigned int magic)
>> +static int qcom_pon_reboot_mode_write(struct reboot_mode_driver *reboot, u64 magic)
>>  {
>>  	struct qcom_pon *pon = container_of
>>  			(reboot, struct qcom_pon, reboot_mode);
>> +	u32 magic_32;
>>  	int ret;
>>
> 
> Since we are doing this change in reboot framework, client driver should know about
> it too about this new check because of framework.

ok.

> 
>> +	if (magic > U32_MAX || (magic << pon->reason_shift) > U32_MAX)
> 
> 
> is this (magic << pon->reason_shift) > U32_MAX really needed ..?

Can be omitted as we already checked magic > U32_MAX. Will
remove it.

> 

[SNIP..]

>> diff --git a/drivers/power/reset/syscon-reboot-mode.c b/drivers/power/reset/syscon-reboot-mode.c
>> index e0772c9f70f7a19cd8ec8a0b7fdbbaa7ba44afd0..3cbd000c512239b12ec51987e900d260540a9dea 100644
>> --- a/drivers/power/reset/syscon-reboot-mode.c
>> +++ b/drivers/power/reset/syscon-reboot-mode.c
>> @@ -20,16 +20,21 @@ struct syscon_reboot_mode {
>>  	u32 mask;
>>  };
>>  
>> -static int syscon_reboot_mode_write(struct reboot_mode_driver *reboot,
>> -				    unsigned int magic)
>> +static int syscon_reboot_mode_write(struct reboot_mode_driver *reboot, u64 magic)
>>  {
>>  	struct syscon_reboot_mode *syscon_rbm;
>> +	u32 magic_32;
>>  	int ret;
>>
> 
> same here

will add comment here.

thanks,
Shivendra