2021-08-30 10:40:47

by Nicolas Saenz Julienne

[permalink] [raw]
Subject: [PATCH] ARM: dts: bcm2711-rpi-4-b: Fix pcie0's unit address

dtbs_check currently complains that:

arch/arm/boot/dts/bcm2711-rpi-4-b.dts:220.10-231.4: Warning
(pci_device_reg): /scb/pcie@7d500000/pci@1,0: PCI unit address format
error, expected "0,0"

Unsurprisingly pci@0,0 is the right address, as illustrated by its reg
property:

&pcie0 {
pci@0,0 {
/*
* As defined in the IEEE Std 1275-1994 document,
* reg is a five-cell address encoded as (phys.hi
* phys.mid phys.lo size.hi size.lo). phys.hi
* should contain the device's BDF as 0b00000000
* bbbbbbbb dddddfff 00000000. The other cells
* should be zero.
*/
reg = <0 0 0 0 0>;
};
};

The bus is clearly 0. So fix it.

Fixes: 258f92d2f840 ("ARM: dts: bcm2711: Add reset controller to xHCI node")
Signed-off-by: Nicolas Saenz Julienne <[email protected]>
---
arch/arm/boot/dts/bcm2711-rpi-4-b.dts | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/boot/dts/bcm2711-rpi-4-b.dts b/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
index f24bdd0870a5..8a77f9e942be 100644
--- a/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
+++ b/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
@@ -217,7 +217,7 @@ phy1: ethernet-phy@1 {
};

&pcie0 {
- pci@1,0 {
+ pci@0,0 {
#address-cells = <3>;
#size-cells = <2>;
ranges;
--
2.31.1


2021-08-30 13:40:56

by Rob Herring (Arm)

[permalink] [raw]
Subject: Re: [PATCH] ARM: dts: bcm2711-rpi-4-b: Fix pcie0's unit address

On Mon, Aug 30, 2021 at 12:39:09PM +0200, Nicolas Saenz Julienne wrote:
> dtbs_check currently complains that:
>
> arch/arm/boot/dts/bcm2711-rpi-4-b.dts:220.10-231.4: Warning
> (pci_device_reg): /scb/pcie@7d500000/pci@1,0: PCI unit address format
> error, expected "0,0"
>
> Unsurprisingly pci@0,0 is the right address, as illustrated by its reg
> property:
>
> &pcie0 {
> pci@0,0 {
> /*
> * As defined in the IEEE Std 1275-1994 document,
> * reg is a five-cell address encoded as (phys.hi
> * phys.mid phys.lo size.hi size.lo). phys.hi
> * should contain the device's BDF as 0b00000000
> * bbbbbbbb dddddfff 00000000. The other cells
> * should be zero.
> */
> reg = <0 0 0 0 0>;
> };
> };
>
> The bus is clearly 0. So fix it.

s/bus/device/

The unit-address format is '<device>,<function>' (and function is
optional). The bus number is not part of the unit-address because that
is dynamic and then the path would not be fixed/known. The bus is part
of 'reg' for true OpenFirmware, but for FDT I think it should always be
0 as the DT is static.

Looks like the child node is wrong (both unit-address and reg) as well:

usb@1,0 {
reg = <0x10000 0 0 0 0>;
resets = <&reset RASPBERRYPI_FIRMWARE_RESET_ID_USB>;
};

It doesn't warn because the bridge node is also missing 'device_type =
"pci";'.

This is all fairly hard to get right (see recent hikey970 patches for a
complex example). I'm thinking about writing a tool that generates a DT
with PCI nodes by reading the PCI hierachy from sysfs.

Rob

2021-08-30 13:55:02

by Nicolas Saenz Julienne

[permalink] [raw]
Subject: Re: [PATCH] ARM: dts: bcm2711-rpi-4-b: Fix pcie0's unit address

On Mon, 2021-08-30 at 08:39 -0500, Rob Herring wrote:
> On Mon, Aug 30, 2021 at 12:39:09PM +0200, Nicolas Saenz Julienne wrote:
> > dtbs_check currently complains that:
> >
> > arch/arm/boot/dts/bcm2711-rpi-4-b.dts:220.10-231.4: Warning
> > (pci_device_reg): /scb/pcie@7d500000/pci@1,0: PCI unit address format
> > error, expected "0,0"
> >
> > Unsurprisingly pci@0,0 is the right address, as illustrated by its reg
> > property:
> >
> > &pcie0 {
> > pci@0,0 {
> > /*
> > * As defined in the IEEE Std 1275-1994 document,
> > * reg is a five-cell address encoded as (phys.hi
> > * phys.mid phys.lo size.hi size.lo). phys.hi
> > * should contain the device's BDF as 0b00000000
> > * bbbbbbbb dddddfff 00000000. The other cells
> > * should be zero.
> > */
> > reg = <0 0 0 0 0>;
> > };
> > };
> >
> > The bus is clearly 0. So fix it.
>
> s/bus/device/
>
> The unit-address format is '<device>,<function>' (and function is
> optional). The bus number is not part of the unit-address because that
> is dynamic and then the path would not be fixed/known. The bus is part
> of 'reg' for true OpenFirmware, but for FDT I think it should always be
> 0 as the DT is static.
>
> Looks like the child node is wrong (both unit-address and reg) as well:
>
> usb@1,0 {
> reg = <0x10000 0 0 0 0>;
> resets = <&reset RASPBERRYPI_FIRMWARE_RESET_ID_USB>;
> };
>
> It doesn't warn because the bridge node is also missing 'device_type =
> "pci";'.
>
> This is all fairly hard to get right (see recent hikey970 patches for a
> complex example). I'm thinking about writing a tool that generates a DT
> with PCI nodes by reading the PCI hierachy from sysfs.

Thanks for the review, I'll fix all those. That tool would be very helpful.

--
Nicolás Sáenz

2021-08-30 16:48:55

by Nicolas Saenz Julienne

[permalink] [raw]
Subject: Re: [PATCH] ARM: dts: bcm2711-rpi-4-b: Fix pcie0's unit address

On Mon, 2021-08-30 at 08:39 -0500, Rob Herring wrote:
> On Mon, Aug 30, 2021 at 12:39:09PM +0200, Nicolas Saenz Julienne wrote:
> > dtbs_check currently complains that:
> >
> > arch/arm/boot/dts/bcm2711-rpi-4-b.dts:220.10-231.4: Warning
> > (pci_device_reg): /scb/pcie@7d500000/pci@1,0: PCI unit address format
> > error, expected "0,0"
> >
> > Unsurprisingly pci@0,0 is the right address, as illustrated by its reg
> > property:
> >
> > &pcie0 {
> > pci@0,0 {
> > /*
> > * As defined in the IEEE Std 1275-1994 document,
> > * reg is a five-cell address encoded as (phys.hi
> > * phys.mid phys.lo size.hi size.lo). phys.hi
> > * should contain the device's BDF as 0b00000000
> > * bbbbbbbb dddddfff 00000000. The other cells
> > * should be zero.
> > */
> > reg = <0 0 0 0 0>;
> > };
> > };
> >
> > The bus is clearly 0. So fix it.
>
> s/bus/device/
>
> The unit-address format is '<device>,<function>' (and function is
> optional). The bus number is not part of the unit-address because that
> is dynamic and then the path would not be fixed/known. The bus is part
> of 'reg' for true OpenFirmware, but for FDT I think it should always be
> 0 as the DT is static.
>
> Looks like the child node is wrong (both unit-address and reg) as well:
>
> usb@1,0 {
> reg = <0x10000 0 0 0 0>;
> resets = <&reset RASPBERRYPI_FIRMWARE_RESET_ID_USB>;
> };
>
> It doesn't warn because the bridge node is also missing 'device_type =
> "pci";'.
>
> This is all fairly hard to get right (see recent hikey970 patches for a
> complex example). I'm thinking about writing a tool that generates a DT
> with PCI nodes by reading the PCI hierachy from sysfs.

Just to double-check I understood everything, with:

lspci -D -PP
0000:00:00.0 PCI bridge: Broadcom Inc. and subsidiaries BCM2711 PCIe Bridge (rev 10)
0000:00:00.0/01:00.0 USB controller: VIA Technologies, Inc. VL805/806 xHCI USB 3.0 Controller (rev 01)

It should look like this:

&pcie0 {
pci@0,0 {
device_type = "pci";
#address-cells = <3>;
#size-cells = <2>;
ranges;

reg = <0 0 0 0 0>;

usb@0,0 {
reg = <0 0 0 0 0>;
resets = <&reset RASPBERRYPI_FIRMWARE_RESET_ID_USB>;
};
};
};

Thanks!

--
Nicolás Sáenz

2021-08-30 21:58:16

by Rob Herring (Arm)

[permalink] [raw]
Subject: Re: [PATCH] ARM: dts: bcm2711-rpi-4-b: Fix pcie0's unit address

On Mon, Aug 30, 2021 at 11:45 AM <[email protected]> wrote:
>
> On Mon, 2021-08-30 at 08:39 -0500, Rob Herring wrote:
> > On Mon, Aug 30, 2021 at 12:39:09PM +0200, Nicolas Saenz Julienne wrote:
> > > dtbs_check currently complains that:
> > >
> > > arch/arm/boot/dts/bcm2711-rpi-4-b.dts:220.10-231.4: Warning
> > > (pci_device_reg): /scb/pcie@7d500000/pci@1,0: PCI unit address format
> > > error, expected "0,0"
> > >
> > > Unsurprisingly pci@0,0 is the right address, as illustrated by its reg
> > > property:
> > >
> > > &pcie0 {
> > > pci@0,0 {
> > > /*
> > > * As defined in the IEEE Std 1275-1994 document,
> > > * reg is a five-cell address encoded as (phys.hi
> > > * phys.mid phys.lo size.hi size.lo). phys.hi
> > > * should contain the device's BDF as 0b00000000
> > > * bbbbbbbb dddddfff 00000000. The other cells
> > > * should be zero.
> > > */
> > > reg = <0 0 0 0 0>;
> > > };
> > > };
> > >
> > > The bus is clearly 0. So fix it.
> >
> > s/bus/device/
> >
> > The unit-address format is '<device>,<function>' (and function is
> > optional). The bus number is not part of the unit-address because that
> > is dynamic and then the path would not be fixed/known. The bus is part
> > of 'reg' for true OpenFirmware, but for FDT I think it should always be
> > 0 as the DT is static.
> >
> > Looks like the child node is wrong (both unit-address and reg) as well:
> >
> > usb@1,0 {
> > reg = <0x10000 0 0 0 0>;
> > resets = <&reset RASPBERRYPI_FIRMWARE_RESET_ID_USB>;
> > };
> >
> > It doesn't warn because the bridge node is also missing 'device_type =
> > "pci";'.
> >
> > This is all fairly hard to get right (see recent hikey970 patches for a
> > complex example). I'm thinking about writing a tool that generates a DT
> > with PCI nodes by reading the PCI hierachy from sysfs.
>
> Just to double-check I understood everything, with:
>
> lspci -D -PP
> 0000:00:00.0 PCI bridge: Broadcom Inc. and subsidiaries BCM2711 PCIe Bridge (rev 10)
> 0000:00:00.0/01:00.0 USB controller: VIA Technologies, Inc. VL805/806 xHCI USB 3.0 Controller (rev 01)
>
> It should look like this:
>
> &pcie0 {
> pci@0,0 {
> device_type = "pci";
> #address-cells = <3>;
> #size-cells = <2>;
> ranges;
>
> reg = <0 0 0 0 0>;
>
> usb@0,0 {
> reg = <0 0 0 0 0>;
> resets = <&reset RASPBERRYPI_FIRMWARE_RESET_ID_USB>;
> };
> };
> };

Yes, that looks correct.

Rob