Re: [RFC][PATCH] PCI: rcar-gen4: Add missing PM ops

[Marek Vasut <marek.vasut@mailbox.org>]

On 9/7/26 12:26 PM, Geert Uytterhoeven wrote:

Hello Geert,

> On Sun, 6 Sept 2026 at 19:32, Marek Vasut
> <marek.vasut+renesas@mailbox.org> wrote:
>> The R-Car Gen4 PCIe controller is part of a power domain. On R-Car S4
>> and V4H, this is an always-on power domain which is not shut down in
>> suspend. On R-Car V4M, this is a dedicated A2PCIPHY power domain,
>> which is shut down during suspend, and the controller loses state,
>> which prevents the PCIe from working after resume.
>>
>> Fix this by adding generic suspend/resume noirq ops for the controller,
>> which tear the link down on suspend, and restart it on resume. Use the
>> same PM ops on all of R-Car Gen4 to gracefully suspend and resume the
>> PCIe link on V4H and S4 too.
>>
>> Test case which demonstrates the problem on R-Car V4M:
>> "
>> $ hexdump -vC /sys/bus/pci/devices/0000:00:00.0/config > /tmp/pre
>> $ echo s2idle > /sys/power/mem_sleep
>> $ echo platform > /sys/power/pm_test
>> $ echo mem > /sys/power/state
>> $ hexdump -vC /sys/bus/pci/devices/0000:00:00.0/config > /tmp/post
>> $ diff -Naru /tmp/pre /tmp/post
>> ...
>> -00000000  12 19 32 00 07 05 10 00  00 00 04 06 00 00 01 00
>> +00000000  12 19 32 00 07 05 10 00  00 00 00 ff 00 00 80 00
>>                                            ^^^^^
>>                                      Class 0604->00ff
>> "
>>
>> Fixes: 0d0c551011df ("PCI: rcar-gen4: Add R-Car Gen4 PCIe controller support for host mode")
>> Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
>> Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
> 
> Thanks, the output of "lspci -v" is now the same before and after
> s2idle.
> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
> 
> I don't have a setup for endpoint mode, so I could not verify or refute
> Sashiko's claim that suspend will crash in endpoint mode.

Same here (thus far).

>> --- a/drivers/pci/controller/dwc/pcie-rcar-gen4.c
>> +++ b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
> 
>> @@ -952,10 +968,14 @@ static const struct of_device_id rcar_gen4_pcie_of_match[] = {
>>   };
>>   MODULE_DEVICE_TABLE(of, rcar_gen4_pcie_of_match);
>>
>> +DEFINE_NOIRQ_DEV_PM_OPS(rcar_gen4_pcie_pm_ops,
>> +                       rcar_gen4_pcie_suspend_noirq, rcar_gen4_pcie_resume_noirq);
>> +
>>   static struct platform_driver rcar_gen4_pcie_driver = {
>>          .driver = {
>>                  .name = "pcie-rcar-gen4",
>>                  .of_match_table = rcar_gen4_pcie_of_match,
>> +               .pm = &rcar_gen4_pcie_pm_ops,
> 
> pm_sleep_ptr(&rcar_gen4_pcie_pm_ops)
Will do in V2.