Re: [PATCH v2] of: address: Work around missing device_type property in pcie nodes

Niklas Söderlund
2020-09-30T16:27:28Z

Hi Marc,

I'm afraid this commit breaks booting my rk3399 device.

I bisected the problem to this patch merged as [1]. I'm testing on a
Scarlet device and I'm using the unmodified upstream
rk3399-gru-scarlet-inx.dtb for my tests.

The problem I'm experience is a black screen after the bootloader and
the device is none responsive over the network. I have no serial console
to this device so I'm afraid I can't tell you if there is anything
useful on to aid debugging there.

If I try to test one commit earlier [2] the system boots as expected and
everything works as it did for me in v5.8 and earlier. I have worked
little with this device and have no clue about what is really on the PCI
buss. But running from [2] I have this info about PCI if it's helpful,
please ask if somethings missing.

# dmesg | grep -i pci
[ 0.003943] PCI/MSI: /interrupt-controller@fee00000/interrupt-controller@fee20000 domain created
[ 0.922022] PCI: CLS 0 bytes, default 64
[ 0.941517] rockchip-pcie f8000000.pcie: host bridge /pcie@f8000000 ranges:
[ 0.941577] rockchip-pcie f8000000.pcie: MEM 0x00fa000000..0x00fbefffff -> 0x00fa000000
[ 0.941962] rockchip-pcie f8000000.pcie: GPIO lookup for consumer ep
[ 0.941981] rockchip-pcie f8000000.pcie: using device tree for GPIO lookup
[ 0.942018] of_get_named_gpiod_flags: parsed 'ep-gpios' property of node '/pcie@f8000000[0]' - status (0)
[ 0.942255] rockchip-pcie f8000000.pcie: no vpcie12v regulator found
[ 4.196248] ehci-pci: EHCI PCI platform driver
[ 4.214639] ohci-pci: OHCI PCI platform driver

# ls /sys/bus/{pci,pci_express}/devices
/sys/bus/pci/devices:

/sys/bus/pci_express/devices:

# ls /sys/bus/{pci,pci_express}/drivers
/sys/bus/pci/drivers:
cavium_rng_pf cavium_rng_vf dwc3-haps ehci-pci exar_serial ohci-pci pcieport serial xhci_hcd

/sys/bus/pci_express/drivers:
pcie_pme

# ls /sys/bus/platform/drivers/rockchip-{pcie,pcie-phy}
/sys/bus/platform/drivers/rockchip-pcie:
bind uevent unbind

/sys/bus/platform/drivers/rockchip-pcie-phy:
bind ff770000.syscon:pcie-phy uevent unbind

1. d1ac0002dd297069 ("of: address: Work around missing device_type property in pcie nodes")
2. 43647929175e2cd3 ("dt: writing-schema: Miscellaneous grammar fixes")

On 2020-08-19 10:42:55 +0100, Marc Zyngier wrote:
> Recent changes to the DT PCI bus parsing made it mandatory for
> device tree nodes describing a PCI controller to have the
> 'device_type = "pci"' property for the node to be matched.
>
> Although this follows the letter of the specification, it
> breaks existing device-trees that have been working fine
> for years. Rockchip rk3399-based systems are a prime example
> of such collateral damage, and have stopped discovering their
> PCI bus.
>
> In order to paper over it, let's add a workaround to the code
> matching the device type, and accept as PCI any node that is
> named "pcie",
>
> A warning will hopefully nudge the user into updating their
> DT to a fixed version if they can, but the incentive is
> obviously pretty small.
>
> Fixes: 2f96593ecc37 ("of_address: Add bus type match for pci ranges parser")
> Suggested-by: Rob Herring <robh+dt@kernel.org>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
> drivers/of/address.c | 16 +++++++++++++++-
> 1 file changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/of/address.c b/drivers/of/address.c
> index 590493e04b01..b37bd9cc2810 100644
> --- a/drivers/of/address.c
> +++ b/drivers/of/address.c
> @@ -128,15 +128,29 @@ static unsigned int of_bus_pci_get_flags(const __be32 *addr)
> * PCI bus specific translator
> */
>
> +static bool of_node_is_pcie(struct device_node *np)
> +{
> + bool is_pcie = of_node_name_eq(np, "pcie");
> +
> + if (is_pcie)
> + pr_warn_once("%pOF: Missing device_type\n", np);
> +
> + return is_pcie;
> +}
> +
> 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
> + *
> + * If none of the device_type match, and that the node name is
> + * "pcie", accept the device as PCI (with a warning).
> */
> return of_node_is_type(np, "pci") || of_node_is_type(np, "pciex") ||
> - of_node_is_type(np, "vci") || of_node_is_type(np, "ht");
> + of_node_is_type(np, "vci") || of_node_is_type(np, "ht") ||
> + of_node_is_pcie(np);
> }
>
> static void of_bus_pci_count_cells(struct device_node *np,
> --
> 2.27.0
>
>
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--
Regards,
Niklas Söderlund