Messages in this thread | ![/](/images/icornerl.gif) | | Date | Sat, 15 Aug 2020 12:22:41 +0100 | From | Marc Zyngier <> | Subject | Re: [PATCH v4 1/5] of_address: Add bus type match for pci ranges parser |
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On 2020-08-14 23:51, Rob Herring wrote: > On Fri, Aug 14, 2020 at 12:21 PM Marc Zyngier <maz@kernel.org> wrote: >> >> Hi all, >> >> On 2020-07-28 16:36, Jiaxun Yang wrote: >> > So the parser can be used to parse range property of ISA bus. >> > >> > As they're all using PCI-like method of range property, there is no >> > need >> > start a new parser. >> > >> > Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com> >> > Reviewed-by: Rob Herring <robh@kernel.org> >> >> This patch, although it looks correct, breaks the RK3399-based >> systems, as they miss the (now required) 'device_type = "pci";' >> property. > > Required since 1990 something...
And yet... The fact that it has been broken from day-1 (3.5 years ago) shows how good we are at enforcing those requirements.
> >> We can fix the in-tree DT, but that's not really an option >> if someone relies on the DT being provided by the firmware >> (I for one definitely do). > > Perhaps time to pay attention to schema errors: > > arch/arm64/boot/dts/rockchip/rk3399-sapphire-excavator.dt.yaml: > pcie@f8000000: 'device_type' is a required property
As long as this isn't part of the normal build flow, these errors will get ignored. I don't even know how to trigger this validation, TBH.
> (I thought dtc would also catch this, but there we look for > device_type and then do PCI checks like node name. I guess we needed > to check for either device_type or the node name...)
That would be much better. At least this *does* run at build time.
> >> I came up with the following hack, which solves the issue for >> me. Definitely not my finest hour, but I really need this box >> to keep going. I will post a patch fixing the DT separately. >> >> Thanks, >> >> M. >> >> From ceef5fd9c4d2005eb577505c68868ebe527c098f Mon Sep 17 00:00:00 >> 2001 >> From: Marc Zyngier <maz@kernel.org> >> Date: Fri, 14 Aug 2020 19:10:12 +0100 >> Subject: [PATCH] of: address: Workaround broken DTs missing the >> 'device_type = >> "pci"' property >> >> Recent changes to the PCI bus parsing made it mandatory for >> device trees nodes describing a PCI controller to have the >> 'device_type = "pci"' property for the node to be matched. >> >> Although this is compliant with the specification, it breaks >> existing device-trees that have been working fine for years >> (the Rockchip rk3399-based systems being a prime example of >> such breakage). >> >> In order to paper over the blunder, let's also match nodes >> that have the "linux,pci-domain" property, as they are >> pretty likely to be PCI nodes. This fixes the issue for >> systems such as the above platforms. >> >> Fixes: 2f96593ecc37 ("of_address: Add bus type match for pci ranges >> parser") >> Signed-off-by: Marc Zyngier <maz@kernel.org> >> --- >> drivers/of/address.c | 5 ++++- >> 1 file changed, 4 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/of/address.c b/drivers/of/address.c >> index 590493e04b01..712e03781a2a 100644 >> --- a/drivers/of/address.c >> +++ b/drivers/of/address.c >> @@ -134,9 +134,12 @@ static int of_bus_pci_match(struct device_node >> *np) >> * "pciex" is PCI Express >> * "vci" is for the /chaos bridge on 1st-gen PCI powermacs >> * "ht" is hypertransport >> + * "linux,pci-domain" is a workaround for broken device trees >> + * lacking the required "device_type" property. > > I would suggest looking for 'pci' or 'pcie' node name instead. > > You should remove linux,pci-domain from rk3399 as it is pointless when > there's a single PCI host bridge.
Indeed. I was clutching at straws here.
> > The other option is fixup the live tree with of_add_property() in the > Rockchip PCI driver. Less likely to impact anyone else.
That's actually a much better solution, thanks for pointing this out. At least I can shout about broken DTs while fixing it up, and the new fix is fairly neat.
I'll post new patches shortly.
Thanks,
M. -- Jazz is not dead. It just smells funny...
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