[PATCH 1/1] riscv: dts: spacemit: Add 'linux,pci-domain' to PCIe nodes for K1

[PATCH 1/1] riscv: dts: spacemit: Add 'linux,pci-domain' to PCIe nodes for K1

[Chukun Pan]

The SpacemiT K1 SoC has 3 PCIe EP controller nodes. Add the
'linux,pci-domain' property to assign a PCI domain number to
each of the controllers instead of assigning it randomly.

Signed-off-by: Chukun Pan <amadeus@jmu.edu.cn>
---
 arch/riscv/boot/dts/spacemit/k1.dtsi | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/riscv/boot/dts/spacemit/k1.dtsi b/arch/riscv/boot/dts/spacemit/k1.dtsi
index 529ec68e9c23..d2015201f8e5 100644
--- a/arch/riscv/boot/dts/spacemit/k1.dtsi
+++ b/arch/riscv/boot/dts/spacemit/k1.dtsi
@@ -1033,6 +1033,7 @@ pcie-bus {
 			#size-cells = <2>;
 			dma-ranges = <0x0 0x00000000 0x0 0x00000000 0x0 0x80000000>,
 				     <0x0 0xb8000000 0x1 0x38000000 0x3 0x48000000>;
+
 			pcie0: pcie@ca000000 {
 				device_type = "pci";
 				compatible = "spacemit,k1-pcie";
@@ -1044,6 +1045,7 @@ pcie0: pcie@ca000000 {
 					    "atu",
 					    "config",
 					    "link";
+				linux,pci-domain = <0>;
 				#address-cells = <3>;
 				#size-cells = <2>;
 				ranges = <0x01000000 0x0 0x00000000 0x0 0x8f002000 0x0 0x00100000>,
@@ -1087,6 +1089,7 @@ pcie1: pcie@ca400000 {
 					    "atu",
 					    "config",
 					    "link";
+				linux,pci-domain = <1>;
 				#address-cells = <3>;
 				#size-cells = <2>;
 				ranges = <0x01000000 0x0 0x00000000 0x0 0x9f002000 0x0 0x00100000>,
@@ -1130,6 +1133,7 @@ pcie2: pcie@ca800000 {
 					    "atu",
 					    "config",
 					    "link";
+				linux,pci-domain = <2>;
 				#address-cells = <3>;
 				#size-cells = <2>;
 				ranges = <0x01000000 0x0 0x00000000 0x0 0xb7002000 0x0 0x00100000>,
-- 
2.25.1

Re: [PATCH 1/1] riscv: dts: spacemit: Add 'linux,pci-domain' to PCIe nodes for K1

[Chukun Pan]

Hi,

> The SpacemiT K1 SoC has 3 PCIe EP controller nodes. Add the
> 'linux,pci-domain' property to assign a PCI domain number to
> each of the controllers instead of assigning it randomly.

Does anyone have any thoughts on this?
Without this patch, the PCI domain number is random.

```
/# find /sys/devices -name net
/sys/devices/platform/soc/soc:pcie-bus/ca800000.pcie/pci0001:00/0001:00:00.0/0001:01:00.0/net
/sys/devices/platform/soc/soc:pcie-bus/ca400000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0/net

/# find /sys/devices -name net
/sys/devices/platform/soc/soc:pcie-bus/ca800000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0/net
/sys/devices/platform/soc/soc:pcie-bus/ca400000.pcie/pci0001:00/0001:00:00.0/0001:01:00.0/net
```

Thanks,
Chukun

Re: [PATCH 1/1] riscv: dts: spacemit: Add 'linux,pci-domain' to PCIe nodes for K1

[Yixun Lan]

Hi Chukun,

On 15:15 Mon 02 Mar     , Chukun Pan wrote:
> Hi,
> 
> > The SpacemiT K1 SoC has 3 PCIe EP controller nodes. Add the
> > 'linux,pci-domain' property to assign a PCI domain number to
> > each of the controllers instead of assigning it randomly.
> 
> Does anyone have any thoughts on this?
> Without this patch, the PCI domain number is random.
> 
You describe what's has been done here, but no why?
Can you add description about why problem with random domain,
and the motivation of the change behind?

from my understanding of reading DT document, either way seems
fine..

> ```
> /# find /sys/devices -name net
> /sys/devices/platform/soc/soc:pcie-bus/ca800000.pcie/pci0001:00/0001:00:00.0/0001:01:00.0/net
> /sys/devices/platform/soc/soc:pcie-bus/ca400000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0/net
> 
> /# find /sys/devices -name net
> /sys/devices/platform/soc/soc:pcie-bus/ca800000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0/net
> /sys/devices/platform/soc/soc:pcie-bus/ca400000.pcie/pci0001:00/0001:00:00.0/0001:01:00.0/net
> ```
> 
> Thanks,
> Chukun
> 

-- 
Yixun Lan (dlan)

Re: [PATCH 1/1] riscv: dts: spacemit: Add 'linux,pci-domain' to PCIe nodes for K1

[Vivian Wang]

On 3/2/26 15:42, Yixun Lan wrote:
> Hi Chukun,
>
> On 15:15 Mon 02 Mar     , Chukun Pan wrote:
>> Hi,
>>
>>> The SpacemiT K1 SoC has 3 PCIe EP controller nodes. Add the
>>> 'linux,pci-domain' property to assign a PCI domain number to
>>> each of the controllers instead of assigning it randomly.
>> Does anyone have any thoughts on this?
>> Without this patch, the PCI domain number is random.
>>
> You describe what's has been done here, but no why?
> Can you add description about why problem with random domain,
> and the motivation of the change behind?
>
> from my understanding of reading DT document, either way seems
> fine..

For example systemd-udevd provides the interface name based on the
segment group / domain number, so if you add an additional PCIe network
card, the name of the network interface will flip between enP0p1s0 and
enP1p1s0, which is a bit inconvenient.

This isn't inherently a problem (these things were never as predictible
as they wanted anyway) but a convenience would still be nice.

Vivian "dramforever" Wang

Re: [PATCH 1/1] riscv: dts: spacemit: Add 'linux,pci-domain' to PCIe nodes for K1

[Chukun Pan]

Hi,

> You describe what's has been done here, but no why?

Because the PCIe boot order is random, if there are two R8125
network cards, their interface names will not be fixed.

For example:
First boot:
pcie@ca400000 -> eth2
pcie@ca800000 -> eth3

Second boot:
pcie@ca400000 -> eth3
pcie@ca800000 -> eth2

If their PCI domain numbers are fixed, I can fix the interface
names by matching /sys/devices using a script.

> Can you add description about why problem with random domain,
> and the motivation of the change behind?

Should I improve the commit messages?

Thanks,
Chukun

Re: [PATCH 1/1] riscv: dts: spacemit: Add 'linux,pci-domain' to PCIe nodes for K1

[Yixun Lan]

Hi Chukun,

On 12:38 Sat 07 Mar     , Chukun Pan wrote:
> Hi,
> 
> > You describe what's has been done here, but no why?
> 
> Because the PCIe boot order is random, if there are two R8125
> network cards, their interface names will not be fixed.
> 
> For example:
> First boot:
> pcie@ca400000 -> eth2
> pcie@ca800000 -> eth3
> 
> Second boot:
> pcie@ca400000 -> eth3
> pcie@ca800000 -> eth2
> 
Ok, I can understand your problem

> If their PCI domain numbers are fixed, I can fix the interface
> names by matching /sys/devices using a script.
> 
If you want to have a fixed interface name, you could setup a udev
rules according to mac address? something like:

$ cat /etc/udev/rules.d/70-network.rules
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="01:02:03:12:34:56", NAME="eth2"

but, I see no harm to add a pci domain property..

> > Can you add description about why problem with random domain,
> > and the motivation of the change behind?
> 
> Should I improve the commit messages?
> 
Yes, please, thanks

> Thanks,
> Chukun
> 

-- 
Yixun Lan (dlan)