+ Bharat On 11/28/2020 1:58 AM, Arnd Bergmann wrote: > On Sat, Nov 28, 2020 at 5:53 AM Florian Fainelli <f.fainelli@xxxxxxxxx> wrote: >> >> On Fri, 16 Oct 2020 17:08:32 +0800, Zhen Lei <thunder.leizhen@xxxxxxxxxx> wrote: >>> The scripts/dtc/checks.c requires that the node have empty "dma-ranges" >>> property must have the same "#address-cells" and "#size-cells" values as >>> the parent node. Otherwise, the following warnings is reported: >>> >>> arch/arm64/boot/dts/broadcom/stingray/stingray-usb.dtsi:7.3-14: Warning \ >>> (dma_ranges_format): /usb:dma-ranges: empty "dma-ranges" property but \ >>> its #address-cells (1) differs from / (2) >>> arch/arm64/boot/dts/broadcom/stingray/stingray-usb.dtsi:7.3-14: Warning \ >>> (dma_ranges_format): /usb:dma-ranges: empty "dma-ranges" property but \ >>> its #size-cells (1) differs from / (2) >>> >>> Arnd Bergmann figured out why it's necessary: >>> Also note that the #address-cells=<1> means that any device under >>> this bus is assumed to only support 32-bit addressing, and DMA will >>> have to go through a slow swiotlb in the absence of an IOMMU. >>> >>> Suggested-by: Arnd Bergmann <arnd@xxxxxxxx> >>> Signed-off-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx> >>> --- >> >> Applied to devicetree-arm64/next, thanks! > > The notification may have gone missing, but I had merged it into v5.10-fixes > already, and as of today, it's in mainline, so you can drop it from your > next branch, or just leave it in if you want to avoid taking things out of > your tree. > > Arnd > It looks like this patch might have caused a regression on Stingray USB. Bharat, could you please confirm? The fix would be to properly define the dma-ranges to be 32-bit (0x0 ~ 0xffffffff) since IOMMU is disabled on this device and the device's DMA engine is on a 32-bit bus. Thanks, Ray -- This electronic communication and the information and any files transmitted with it, or attached to it, are confidential and are intended solely for the use of the individual or entity to whom it is addressed and may contain information that is confidential, legally privileged, protected by privacy laws, or otherwise restricted from disclosure to anyone else. If you are not the intended recipient or the person responsible for delivering the e-mail to the intended recipient, you are hereby notified that any use, copying, distributing, dissemination, forwarding, printing, or copying of this e-mail is strictly prohibited. If you received this e-mail in error, please return the e-mail to the sender, delete it from your computer, and destroy any printed copy of it.
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