Re: [PATCH 5/5] arm64: dts: qcom: qcs8550: add QCS8550 RB5Gen2 board support

[Joe Sandom <jsandom@axon.com>]

On Tue, Apr 07, 2026 at 09:44:34PM +0530, Manivannan Sadhasivam wrote:
> On Tue, Apr 07, 2026 at 12:39:25PM +0100, Joe Sandom wrote:
> 
> [...]
> 
> > > > +&pcie0 {
> > > > +	wake-gpios = <&tlmm 96 GPIO_ACTIVE_HIGH>;
> > > > +	perst-gpios = <&tlmm 94 GPIO_ACTIVE_LOW>;
> > > > +
> > > > +	pinctrl-0 = <&pcie0_default_state>;
> > > > +	pinctrl-names = "default";
> > > > +
> > > > +	iommu-map = <0x0 &apps_smmu 0x1400 0x1>,
> > > > +		    <0x100 &apps_smmu 0x1401 0x1>,
> > > > +		    <0x208 &apps_smmu 0x1402 0x1>,
> > > > +		    <0x210 &apps_smmu 0x1403 0x1>,
> > > > +		    <0x218 &apps_smmu 0x1404 0x1>,
> > > > +		    <0x300 &apps_smmu 0x1407 0x1>,
> > > > +		    <0x400 &apps_smmu 0x1408 0x1>,
> > > > +		    <0x500 &apps_smmu 0x140c 0x1>,
> > > > +		    <0x501 &apps_smmu 0x140e 0x1>;
> > > > +
> > > > +	/delete-property/ msi-map;
> > > 
> > > Why?
> > I tried extending the msi-map to cover the RIDs from the QPS615
> > PCIe switch (matching the iommu-map entries), but this caused
> > ITS MAPD command timeouts.
> 
> I'm not aware of any specific issue with ITS on this chipset. At what time did
> you see the timeout? During probe?
So when I set msi-map to match the iommu-map entries, I got this;
[    0.000000] ITS [mem 0x17140000-0x1717ffff]
[   11.085152] ath12k_wifi7_pci 0001:04:00.0: BAR 0 assigned
[   11.115762] ath12k_wifi7_pci 0001:04:00.0: Wi-Fi 7 Hardware name: wcn7850 hw2.0
[   11.153632] ath12k_wifi7_pci 0001:04:00.0: MSI vectors: 16
[   11.252398] mhi mhi0: Requested to power ON
.........
[  101.596274] mhi mhi0: Wait for device to enter SBL or Mission mode
[  101.603098] ath12k_wifi7_pci 0001:04:00.0: failed to set mhi state: POWER_ON(2)
[  101.610632] ath12k_wifi7_pci 0001:04:00.0: failed to start mhi: -110
[  101.617171] ath12k_wifi7_pci 0001:04:00.0: failed to power up :-110
[  101.794431] ath12k_wifi7_pci 0001:04:00.0: probe failed with error -110
[  103.158872] ITS queue timeout (12640 12609)
[  103.163183] ITS cmd its_build_mapd_cmd failed

With msi-map removed, I got this;
[   11.469642] ath12k_wifi7_pci 0001:04:00.0: BAR 0 assigned
[   11.490059] ath12k_wifi7_pci 0001:04:00.0: Wi-Fi 7 Hardware name: wcn7850 hw2.0
[   11.497787] ath12k_wifi7_pci 0001:04:00.0: MSI vectors: 16
[   11.559958] mhi mhi0: Requested to power ON
[   11.567375] mhi mhi0: Power on setup success
[   11.693069] mhi mhi0: Wait for device to enter SBL or Mission mode
[   12.185946] ath12k_wifi7_pci 0001:04:00.0: chip_id 0x2 ... soc_id 0x40170200
[   12.482168] ath12k_wifi7_pci 0001:04:00.0 wlP1p4s0: renamed from wlan0
> 
> > From what I could gather, deleting
> > msi-map forces the PCIe controller to fall back to the internal
> > iMSI-RX module, where this worked properly.
> > 
> 
> That's true.
> 
> > For reference, I checked the RB3gen2 since it also uses a QPS615
> > and there doesn't seem to be any msi-map defined (in kodiak.dtsi).
> > 
> 
> But Kodiak has no MSI support (no LPIs). That's why the ITS node is disabled and
> iommu-map is used.
Good to know, thanks Mani.
> 
> > Any recommendations to resolve this properly?
> 
> I will also check internally in the meantime.
Thanks Mani
> 
> - Mani
> 
> -- 
> மணிவண்ணன் சதாசிவம்