| Message ID | 20230224105906.16540-3-manivannan.sadhasivam@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | Add PCIe RC support to Qcom SDX55 SoC | expand |
On Fri, Feb 24, 2023 at 04:28:55PM +0530, Manivannan Sadhasivam wrote: > Most of the PCIe controllers require iommu support to function properly. > So let's add them to the binding. > > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> > --- > Documentation/devicetree/bindings/pci/qcom,pcie.yaml | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/Documentation/devicetree/bindings/pci/qcom,pcie.yaml b/Documentation/devicetree/bindings/pci/qcom,pcie.yaml > index a3639920fcbb..f48d0792aa57 100644 > --- a/Documentation/devicetree/bindings/pci/qcom,pcie.yaml > +++ b/Documentation/devicetree/bindings/pci/qcom,pcie.yaml > @@ -64,6 +64,11 @@ properties: > > dma-coherent: true > > + iommus: > + maxItems: 1 > + > + iommu-map: true > + I think both properties together doesn't make sense unless the PCI host itself does DMA in addition to PCI bus devices doing DMA. Rob
On Mon, Feb 27, 2023 at 01:55:35PM -0600, Rob Herring wrote: > On Fri, Feb 24, 2023 at 04:28:55PM +0530, Manivannan Sadhasivam wrote: > > Most of the PCIe controllers require iommu support to function properly. > > So let's add them to the binding. > > > > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> > > --- > > Documentation/devicetree/bindings/pci/qcom,pcie.yaml | 5 +++++ > > 1 file changed, 5 insertions(+) > > > > diff --git a/Documentation/devicetree/bindings/pci/qcom,pcie.yaml b/Documentation/devicetree/bindings/pci/qcom,pcie.yaml > > index a3639920fcbb..f48d0792aa57 100644 > > --- a/Documentation/devicetree/bindings/pci/qcom,pcie.yaml > > +++ b/Documentation/devicetree/bindings/pci/qcom,pcie.yaml > > @@ -64,6 +64,11 @@ properties: > > > > dma-coherent: true > > > > + iommus: > > + maxItems: 1 > > + > > + iommu-map: true > > + > > I think both properties together doesn't make sense unless the PCI host > itself does DMA in addition to PCI bus devices doing DMA. > How? With "iommus", we specify the SMR mask along with the starting SID and with iommu-map, the individual SID<->BDF mapping is specified. This has nothing to do with host DMA capabilities. Thanks, Mani > Rob
+Robin On Tue, Feb 28, 2023 at 2:20 AM Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> wrote: > > On Mon, Feb 27, 2023 at 01:55:35PM -0600, Rob Herring wrote: > > On Fri, Feb 24, 2023 at 04:28:55PM +0530, Manivannan Sadhasivam wrote: > > > Most of the PCIe controllers require iommu support to function properly. > > > So let's add them to the binding. > > > > > > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> > > > --- > > > Documentation/devicetree/bindings/pci/qcom,pcie.yaml | 5 +++++ > > > 1 file changed, 5 insertions(+) > > > > > > diff --git a/Documentation/devicetree/bindings/pci/qcom,pcie.yaml b/Documentation/devicetree/bindings/pci/qcom,pcie.yaml > > > index a3639920fcbb..f48d0792aa57 100644 > > > --- a/Documentation/devicetree/bindings/pci/qcom,pcie.yaml > > > +++ b/Documentation/devicetree/bindings/pci/qcom,pcie.yaml > > > @@ -64,6 +64,11 @@ properties: > > > > > > dma-coherent: true > > > > > > + iommus: > > > + maxItems: 1 > > > + > > > + iommu-map: true > > > + > > > > I think both properties together doesn't make sense unless the PCI host > > itself does DMA in addition to PCI bus devices doing DMA. > > > > How? With "iommus", we specify the SMR mask along with the starting SID and with > iommu-map, the individual SID<->BDF mapping is specified. This has nothing to > do with host DMA capabilities. I spoke with Robin offline and he agrees that having both is broken at least in RC mode. He pointed out the issue is similar to this one on Tegra[1]. Rob [1] https://lore.kernel.org/all/AS8P193MB2095640357779A7F9B6026F8D2A19@AS8P193MB2095.EURP193.PROD.OUTLOOK.COM/
On Wed, Mar 01, 2023 at 08:58:51AM -0600, Rob Herring wrote: > +Robin > > On Tue, Feb 28, 2023 at 2:20 AM Manivannan Sadhasivam > <manivannan.sadhasivam@linaro.org> wrote: > > > > On Mon, Feb 27, 2023 at 01:55:35PM -0600, Rob Herring wrote: > > > On Fri, Feb 24, 2023 at 04:28:55PM +0530, Manivannan Sadhasivam wrote: > > > > Most of the PCIe controllers require iommu support to function properly. > > > > So let's add them to the binding. > > > > > > > > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> > > > > --- > > > > Documentation/devicetree/bindings/pci/qcom,pcie.yaml | 5 +++++ > > > > 1 file changed, 5 insertions(+) > > > > > > > > diff --git a/Documentation/devicetree/bindings/pci/qcom,pcie.yaml b/Documentation/devicetree/bindings/pci/qcom,pcie.yaml > > > > index a3639920fcbb..f48d0792aa57 100644 > > > > --- a/Documentation/devicetree/bindings/pci/qcom,pcie.yaml > > > > +++ b/Documentation/devicetree/bindings/pci/qcom,pcie.yaml > > > > @@ -64,6 +64,11 @@ properties: > > > > > > > > dma-coherent: true > > > > > > > > + iommus: > > > > + maxItems: 1 > > > > + > > > > + iommu-map: true > > > > + > > > > > > I think both properties together doesn't make sense unless the PCI host > > > itself does DMA in addition to PCI bus devices doing DMA. > > > > > > > How? With "iommus", we specify the SMR mask along with the starting SID and with > > iommu-map, the individual SID<->BDF mapping is specified. This has nothing to > > do with host DMA capabilities. > > I spoke with Robin offline and he agrees that having both is broken at > least in RC mode. He pointed out the issue is similar to this one on > Tegra[1]. > Looked into that thread and concluded that "iommus" property should go away. Submitted a patch [1] to remove that property from PCIe nodes of all Qualcomm SoCs. Thanks for pointing out! Will update this bindings patch in next revision. - Mani [1] https://lore.kernel.org/linux-arm-msm/20230308075648.134119-1-manivannan.sadhasivam@linaro.org/ > Rob > > [1] https://lore.kernel.org/all/AS8P193MB2095640357779A7F9B6026F8D2A19@AS8P193MB2095.EURP193.PROD.OUTLOOK.COM/
diff --git a/Documentation/devicetree/bindings/pci/qcom,pcie.yaml b/Documentation/devicetree/bindings/pci/qcom,pcie.yaml index a3639920fcbb..f48d0792aa57 100644 --- a/Documentation/devicetree/bindings/pci/qcom,pcie.yaml +++ b/Documentation/devicetree/bindings/pci/qcom,pcie.yaml @@ -64,6 +64,11 @@ properties: dma-coherent: true + iommus: + maxItems: 1 + + iommu-map: true + interconnects: maxItems: 2
Most of the PCIe controllers require iommu support to function properly. So let's add them to the binding. Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> --- Documentation/devicetree/bindings/pci/qcom,pcie.yaml | 5 +++++ 1 file changed, 5 insertions(+)