Re: [PATCH] PCI: quirks: Add warm reset quirk for IBM Spyre accelerator

[Shivaprasad G Bhat <sbhat@linux.ibm.com>]

Hi Bjorn,

Thanks for taking a look.

On 8/5/26 10:48 PM, Bjorn Helgaas wrote:
> On Wed, Aug 05, 2026 at 06:21:32PM +0530, Avinash Roy wrote:
>> From: Shivaprasad G Bhat <sbhat@linux.ibm.com>
>>
>> The IBM Spyre accelerator (PCI ID 1014:06a7) requires a dedicated warm
>> reset method for reliable EEH recovery on pSeries/ppc64 platforms.
>>
>> FLR alone is insufficient because it does not re-initialize the Spyre
>> firmware state machine. On ppc64 with EEH enabled,
>> pcibios_set_pcie_reset_state() is overridden in
>> arch/powerpc/kernel/eeh.c to drive the platform-level PERST# signal via
>> EEH PE operations, which is the correct mechanism for full device
>> recovery after an EEH event.
> 
> This makes it sound like this mechanism is needed for EEH recovery for
> *all* devices, not just Spyre.  If that's the case it sounds like we
> need more than just a Spyre-specific quirk.

Now I re-read it, The second statement needs to be re-worded. It does 
sound like its true for all devices. Quirk is only for the Spyre card.

Will post a v2 fixing the same.

Thanks and Regards,
Shivaprasad

> 
>> The reset function is placed in arch/powerpc/platforms/pseries/pci.c
>> where the EEH infrastructure is already present, declared in
>> pseries.h, and registered in the generic pci_dev_reset_methods[] table
>> in drivers/pci/quirks.c under a CONFIG_PPC_PSERIES guard.
>>
>> This reset method is only registered when CONFIG_PPC_PSERIES is enabled,
>> so it is not available on other platforms.
>>
>> Reset sequence:
>>    - Assert PERST# via pcie_warm_reset, hold 250 ms
>>    - Deassert PERST# via pcie_deassert_reset
>>    - Wait 250 ms for PCIe link retrain and device recovery
>>
>> Signed-off-by: Avinash Roy <avinash.roy1@linux.ibm.com>
>> Signed-off-by: Shivaprasad G Bhat <sbhat@linux.ibm.com>
>> ---
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