Re: [PATCH v5 1/2] firmware: qcom: scm: Register gunyah watchdog device

[Dmitry Baryshkov]

On Tue, Nov 11, 2025 at 11:41:51AM +0100, Krzysztof Kozlowski wrote:
> On 11/11/2025 11:34, Dmitry Baryshkov wrote:
> > On Tue, Nov 11, 2025 at 10:51:43AM +0530, Pavan Kondeti wrote:
> >> On Mon, Nov 10, 2025 at 09:43:53AM +0530, Pavan Kondeti wrote:
> >>> On Sat, Nov 08, 2025 at 07:26:46PM +0200, Dmitry Baryshkov wrote:
> >>>>> +static void qcom_scm_gunyah_wdt_free(void *data)
> >>>>> +{
> >>>>> +	struct platform_device *gunyah_wdt_dev = data;
> >>>>> +
> >>>>> +	platform_device_unregister(gunyah_wdt_dev);
> >>>>> +}
> >>>>> +
> >>>>> +static void qcom_scm_gunyah_wdt_init(struct qcom_scm *scm)
> >>>>> +{
> >>>>> +	struct platform_device *gunyah_wdt_dev;
> >>>>> +	struct device_node *np;
> >>>>> +	bool of_wdt_available;
> >>>>> +	int i;
> >>>>> +	uuid_t gunyah_uuid = UUID_INIT(0xc1d58fcd, 0xa453, 0x5fdb, 0x92, 0x65,
> >>>>
> >>>> static const?
> >>>>
> >>>>> +				       0xce, 0x36, 0x67, 0x3d, 0x5f, 0x14);
> >>>>> +	static const char * const of_wdt_compatible[] = {
> >>>>> +		"qcom,kpss-wdt",
> >>>>> +		"arm,sbsa-gwdt",
> >>>>> +	};
> >>>>> +
> >>>>> +	/* Bail out if we are not running under Gunyah */
> >>>>> +	if (!arm_smccc_hypervisor_has_uuid(&gunyah_uuid))
> >>>>> +		return;
> >>>>
> >>>> This rquires 'select HAVE_ARM_SMCCC_DISCOVERY'
> >>>>
> >>>
> >>> Probably `depends on HAVE_ARM_SMCCC_DISCOVERY` is correct here.
> >>>
> >>
> >> Dmitry / Bjorn,
> >>
> >> We are debating on this internally on how to resolve this dependency
> >>
> >> - QCOM_SCM depends on HAVE_ARM_SMCCC_DISCOVERY which means restricting
> >>   QCOM_SCM compilation than what it is today.
> >>
> >> - Adding #ifdefry around arm_smccc_hypervisor_has_uuid usage in qcom scm driver 
> >>
> >> - Adding stub for `arm_smccc_hypervisor_has_uuid()` which is not done
> >>   for any of the functions defined in drivers/firmware/smccc/smccc.c
> >>
> >> We are trending towards the first option above. Please let us know if
> >> you think otherwise.
> > 
> > The same as before: 'select HAVE_ARM_SMCCC_DISCOVERY'.
> 
> HAVE_ARM_SMCCC_DISCOVERY has a dependency which is not always selected
> (e.g. ARM32), thus selecting it might lead to warnings of unmet
> dependencies.

Then `if (!IS_ENABLED(CONFIG_HAVE_ARM_SMCCC_DISCOVERY))` might be a good
option here (and depend on GICv3 selecting it).

> Whichever they choose here, they need to be sure to
> actually compile test it, because existing patch lacks that and reports
> are proving lack of building.
> 
> Best regards,
> Krzysztof

-- 
With best wishes
Dmitry