Re: [PATCH v3] firmware: stratix10-svc: add PSCI secondary CPU offline on warm reboot for agilex and stratix10

["NG, ADRIAN HO YIN" <adrian.ho.yin.ng@altera.com>]

On 9/5/2026 12:55 AM, Dinh Nguyen wrote:
>
>
> On 9/4/26 00:52, Adrian Ng Ho Yin wrote:
>> On Agilex7 and Stratix10 SoCs, secondary CPUs must be offlined before
>> a warm reboot to ensure a clean PSCI state. Agilex5 warm reset is a
>> SDM-owned HPS reset that holds secondaries in the new reset-release 
>> until
>> ATF releases them, so the secondary cores dont have to be put offline
>> first. Register a reboot notifier that calls remove_cpu() on each
>> secondary CPU when SYS_RESTART is triggered in REBOOT_WARM mode.
>>
>> A snapshot of cpu_online_mask is taken before the loop since 
>> remove_cpu()
>> modifies the mask as CPUs go down. CPU 0 is excluded as it is typically
>> not hotpluggable. Failures are logged and the loop continues so the
>> reboot is not blocked by a single CPU that refuses to offline.
>> The of_device_id table carries a per-compatible pdata flag to enable the
>> notifier only on platforms that need it; Agilex5 leaves the flag unset.
>>
>> The notifier is unregistered at the start of remove(), before async
>> channel teardown, to prevent a reboot notification from racing with
>> driver shutdown.
>>
>> Signed-off-by: Adrian Ng Ho Yin <adrian.ho.yin.ng@altera.com>
>> ---
>> changelog:
>> v2 -> v3:
>> - Use ctrl in psci_offline_secondary_cpus() via dev_err(ctrl->dev, ...)
>>    instead of pr_err(). The controller pointer was unused; this both
>>    consumes it and attributes the failure to the svc device.
>> - Keep of_device_id.data / stratix10_svc_pdata rather than dropping it
>>    because both intel,stratix10-svc and intel,agilex-svc happen to share
>>    the same notifier path. A separate patch adds intel,agilex5-svc 
>> without
>>    .data so Agilex5 does not run this sequence. Agilex5 warm reset is an
>>    SDM-owned HPS reset (REBOOT_HPS) that holds secondaries in the
>>    reset-release / P-channel block until ATF CPURSTRELEASE; Linux must
>>    not PSCI-offline them first.
>>
>> v1 -> v2:
>> - Drop workqueue fan-out: remove_cpu() serialises on device_hotplug_lock
>>    internally so concurrent workers provided no parallelism. Replace 
>> with
>>    a single sequential loop over a cpumask snapshot.
>> - Fix CPU identity bug: get_cpu()/put_cpu() did not prevent task 
>> migration
>>    and the notifier can run on any CPU before migrate_to_reboot_cpu().
>>    Exclude CPU 0 (typically not hotpluggable) and offline everything 
>> else.
>> - Fix pre-count race: the two-loop atomic pre-count had a window where a
>>    concurrent hotplug event could cause dec_and_test() to fire 
>> prematurely.
>>    Eliminated entirely along with the completion and timeout.
>> - Replace of_device_is_compatible() checks with a stratix10_svc_pdata
>>    struct carried in of_device_id.data, retrieved via 
>> of_device_get_match_data().
>> - Move psci_cpu_off_teardown() to the top of stratix10_svc_drv_remove(),
>>    before async channel teardown, to close the race where a warm-reboot
>>    notification could fire while the driver is being dismantled.
>>
>> ---
>>   drivers/firmware/stratix10-svc.c | 88 ++++++++++++++++++++++++++++++--
>>   1 file changed, 85 insertions(+), 3 deletions(-)
>>
> I had some erros apply this patch, but was able to finally do it. 
> Please double-check the applied patch on my branch: 
> socfpga_firmware_for_v7.4

Hi Dinh,

The patch looks good on socfpga_firmware_for_v7.4.

Thank You
Adrian