PCI trouble on mvebu (Turris Omnia)

[Toke Høiland-Jørgensen]

Bjorn Helgaas <helgaas at kernel.org> writes:

> On Wed, Oct 28, 2020 at 02:36:13PM +0100, Toke Høiland-Jørgensen wrote:
>> Toke Høiland-Jørgensen <toke at redhat.com> writes:
>> 
>> > Bjorn Helgaas <helgaas at kernel.org> writes:
>> >
>> >> [+cc vtolkm]
>> >>
>> >> On Tue, Oct 27, 2020 at 04:43:20PM +0100, Toke Høiland-Jørgensen wrote:
>> >>> Hi everyone
>> >>> 
>> >>> I'm trying to get a mainline kernel to run on my Turris Omnia, and am
>> >>> having some trouble getting the PCI bus to work correctly. Specifically,
>> >>> I'm running a 5.10-rc1 kernel (torvalds/master as of this moment), with
>> >>> the resource request fix[0] applied on top.
>> >>> 
>> >>> The kernel boots fine, and the patch in [0] makes the PCI devices show
>> >>> up. But I'm still getting initialisation errors like these:
>> >>> 
>> >>> [    1.632709] pci 0000:01:00.0: BAR 0: error updating (0xe0000004 != 0xffffffff)
>> >>> [    1.632714] pci 0000:01:00.0: BAR 0: error updating (high 0x000000 != 0xffffffff)
>> >>> [    1.632745] pci 0000:02:00.0: BAR 0: error updating (0xe0200004 != 0xffffffff)
>> >>> [    1.632750] pci 0000:02:00.0: BAR 0: error updating (high 0x000000 != 0xffffffff)
>> >>> 
>> >>> and the WiFi drivers fail to initialise with what appears to me to be
>> >>> errors related to the bus rather than to the drivers themselves:
>> >>> 
>> >>> [    3.509878] ath: phy0: Mac Chip Rev 0xfffc0.f is not supported by this driver
>> >>> [    3.517049] ath: phy0: Unable to initialize hardware; initialization status: -95
>> >>> [    3.524473] ath9k 0000:01:00.0: Failed to initialize device
>> >>> [    3.530081] ath9k: probe of 0000:01:00.0 failed with error -95
>> >>> [    3.536012] ath10k_pci 0000:02:00.0: of_irq_parse_pci: failed with rc=134
>> >>> [    3.543049] pci 0000:00:02.0: enabling device (0140 -> 0142)
>> >>> [    3.548735] ath10k_pci 0000:02:00.0: can't change power state from D3hot to D0 (config space inaccessible)
>> >>> [    3.588592] ath10k_pci 0000:02:00.0: failed to wake up device : -110
>> >>> [    3.595098] ath10k_pci: probe of 0000:02:00.0 failed with error -110
>> >>> 
>> >>> lspci looks OK, though:
>> >>> 
>> >>> # lspci
>> >>> 00:01.0 PCI bridge: Marvell Technology Group Ltd. Device 6820 (rev 04)
>> >>> 00:02.0 PCI bridge: Marvell Technology Group Ltd. Device 6820 (rev 04)
>> >>> 00:03.0 PCI bridge: Marvell Technology Group Ltd. Device 6820 (rev 04)
>> >>> 01:00.0 Network controller: Qualcomm Atheros AR9287 Wireless Network Adapter (PCI-Express) (rev 01)
>> >>> 02:00.0 Network controller: Qualcomm Atheros QCA986x/988x 802.11ac Wireless Network Adapter (rev ff)
>> >>> 
>> >>> Does anyone have any clue what could be going on here? Is this a bug, or
>> >>> did I miss something in my config or other initialisation? I've tried
>> >>> with both the stock u-boot distributed with the board, and with an
>> >>> upstream u-boot from latest master; doesn't seem to make any different.
>> >>
>> >> Can you try turning off CONFIG_PCIEASPM?  We had a similar recent
>> >> report at https://bugzilla.kernel.org/show_bug.cgi?id=209833 but I
>> >> don't think we have a fix yet.
>> >
>> > Yes! Turning that off does indeed help! Thanks a bunch :)
>> >
>> > You mention that bisecting this would be helpful - I can try that
>> > tomorrow; any idea when this was last working?
>> 
>> OK, so I tried to bisect this, but, erm, I couldn't find a working
>> revision to start from? I went all the way back to 4.10 (which is the
>> first version to include the device tree file for the Omnia), and even
>> on that, the wireless cards were failing to initialise with ASPM
>> enabled...
>
> I have no personal experience with this device; all I know is that the
> bugzilla suggests that it worked in v5.4, which isn't much help.
>
> Possibly the apparent regression was really a .config change, i.e.,
> CONFIG_PCIEASPM was disabled in the v5.4 kernel vtolkm@ tested and it
> "worked" but got enabled later and it started failing?

Yeah, I suspect so. The OpenWrt config disables CONFIG_PCIEASPM by
default and only turns it on for specific targets. So I guess that it's
most likely that this has never worked...

> Maybe the debug patch below would be worth trying to see if it makes
> any difference?  If it *does* help, try omitting the first hunk to see
> if we just need to apply the quirk_enable_clear_retrain_link() quirk.

Tried, doesn't help...

-Toke