[PATCH 2/4] arm64: dts: imx95: switch usb3 controller to flattened model

[Xu Yang]

On Thu, Apr 23, 2026 at 12:07:42PM +0000, Peng Fan wrote:
> > Subject: Re: [PATCH 2/4] arm64: dts: imx95: switch usb3 controller to
> > flattened model
> > 
> > On Tue, Apr 21, 2026 at 11:53:12PM -0400, Frank Li wrote:
> > > On Tue, Apr 21, 2026 at 06:55:01PM +0800, Xu Yang wrote:
> > > > Switch to use flattened model for USB3 controller. To enable USB
> > > > controller with restricted DMA access range to work correctly, add
> > a
> > > > pseudo simple-bus to constrain the dma address.
> > >
> > > i.mx95 should fix >4G dma space's problem. Does it impact other no-
> > nxp
> > > boards?
> > 
> > Yes, i.MX95 has fixed >3G address DMA access problem.
> > 
> > It's another issue. HSIO domain only support 36 bit bus access. If not
> > use smmu, no any issue. If use smmu, it will allocate memory space of
> > 36 bit < iova < 48bit.
> > HSIO can't handle this case.
> 
> If using smmu, iova will be in range {36bit, 48bit}? How?

Yes, if use smmu and not set dma-range:

[    3.139529] dwc3 4c100000.usb: dwc3_alloc_one_event_buffer evt->dma:0x0000fffffffff000 len:4096

if use smmu and set dma-range:

[    3.136849] dwc3 4c100000.usb: dwc3_alloc_one_event_buffer evt->dma:0x0000000ffffff000 len:4096

Thanks,
Xu Yang