Hi Rob, On 3/31/2020 10:15 PM, Rob Herring wrote: > On Tue, Mar 31, 2020 at 09:08:12AM +0530, Kishon Vijay Abraham I wrote: >> Hi Rob, >> >> On 3/30/2020 9:31 PM, Rob Herring wrote: >>> On Fri, Mar 27, 2020 at 04:17:25PM +0530, Kishon Vijay Abraham I wrote: >>>> Deprecate cdns,max-outbound-regions and cdns,no-bar-match-nbits for >>>> host mode as both these could be derived from "ranges" and "dma-ranges" >>>> property. "cdns,max-outbound-regions" property would still be required >>>> for EP mode. >>>> >>>> Signed-off-by: Kishon Vijay Abraham I <kishon@xxxxxx> >>>> --- >>>> .../bindings/pci/cdns,cdns-pcie-ep.yaml | 2 +- >>>> .../bindings/pci/cdns,cdns-pcie-host.yaml | 3 +-- >>>> .../devicetree/bindings/pci/cdns-pcie-ep.yaml | 25 +++++++++++++++++++ >>>> .../bindings/pci/cdns-pcie-host.yaml | 10 ++++++++ >>>> .../devicetree/bindings/pci/cdns-pcie.yaml | 8 ------ >>>> 5 files changed, 37 insertions(+), 11 deletions(-) >>>> create mode 100644 Documentation/devicetree/bindings/pci/cdns-pcie-ep.yaml >>>> >>>> diff --git a/Documentation/devicetree/bindings/pci/cdns,cdns-pcie-ep.yaml b/Documentation/devicetree/bindings/pci/cdns,cdns-pcie-ep.yaml >>>> index 2996f8d4777c..50ce5d79d2c7 100644 >>>> --- a/Documentation/devicetree/bindings/pci/cdns,cdns-pcie-ep.yaml >>>> +++ b/Documentation/devicetree/bindings/pci/cdns,cdns-pcie-ep.yaml >>>> @@ -10,7 +10,7 @@ maintainers: >>>> - Tom Joseph <tjoseph@xxxxxxxxxxx> >>>> >>>> allOf: >>>> - - $ref: "cdns-pcie.yaml#" >>>> + - $ref: "cdns-pcie-ep.yaml#" >>>> - $ref: "pci-ep.yaml#" >>>> >>>> properties: >>>> diff --git a/Documentation/devicetree/bindings/pci/cdns,cdns-pcie-host.yaml b/Documentation/devicetree/bindings/pci/cdns,cdns-pcie-host.yaml >>>> index cabbe46ff578..84a8f095d031 100644 >>>> --- a/Documentation/devicetree/bindings/pci/cdns,cdns-pcie-host.yaml >>>> +++ b/Documentation/devicetree/bindings/pci/cdns,cdns-pcie-host.yaml >>>> @@ -45,8 +45,6 @@ examples: >>>> #size-cells = <2>; >>>> bus-range = <0x0 0xff>; >>>> linux,pci-domain = <0>; >>>> - cdns,max-outbound-regions = <16>; >>>> - cdns,no-bar-match-nbits = <32>; >>>> vendor-id = <0x17cd>; >>>> device-id = <0x0200>; >>>> >>>> @@ -57,6 +55,7 @@ examples: >>>> >>>> ranges = <0x02000000 0x0 0x42000000 0x0 0x42000000 0x0 0x1000000>, >>>> <0x01000000 0x0 0x43000000 0x0 0x43000000 0x0 0x0010000>; >>>> + dma-ranges = <0x02000000 0x0 0x0 0x0 0x0 0x1 0x00000000>; >>>> >>>> #interrupt-cells = <0x1>; >>>> >>>> diff --git a/Documentation/devicetree/bindings/pci/cdns-pcie-ep.yaml b/Documentation/devicetree/bindings/pci/cdns-pcie-ep.yaml >>>> new file mode 100644 >>>> index 000000000000..6150a7a7bdbf >>>> --- /dev/null >>>> +++ b/Documentation/devicetree/bindings/pci/cdns-pcie-ep.yaml >>>> @@ -0,0 +1,25 @@ >>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) >>>> +%YAML 1.2 >>>> +--- >>>> +$id: "http://devicetree.org/schemas/pci/cdns-pcie-ep.yaml#"; >>>> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"; >>>> + >>>> +title: Cadence PCIe Device >>>> + >>>> +maintainers: >>>> + - Tom Joseph <tjoseph@xxxxxxxxxxx> >>>> + >>>> +allOf: >>>> + - $ref: "cdns-pcie.yaml#" >>>> + >>>> +properties: >>>> + cdns,max-outbound-regions: >>>> + description: maximum number of outbound regions >>>> + allOf: >>>> + - $ref: /schemas/types.yaml#/definitions/uint32 >>>> + minimum: 1 >>>> + maximum: 32 >>>> + default: 32 >>> >>> I have a feeling that as the PCI endpoint binding evolves this won't be >>> necessary. I can see a common need to define the number of BARs for an >>> endpoint and then this will again just be error checking. >> >> For every buffer given by the host, we have to create a new outbound >> translation. If there are no outbound regions, we have to report the error to >> the endpoint function driver. At-least for reporting the error, we'd need to >> have this binding no? > > But isn't the endpoint defined to have some number of BARs? The PCI host > doesn't decide that. cdns,max-outbound-regions defined here doesn't configure the BARs. BARs provide an interface for the host to access the endpoints memory. IOW for BARs we configure the inbound address translation unit. cdns,max-outbound-regions is used while configuring the outbound address translation unit. Outbound regions are used while the endpoint access host memory and in that path endpoint BARs doesn't come. > >>> >>> What's the result if you write to a non-existent region in register >>> CDNS_PCIE_AT_OB_REGION_PCI_ADDR0/1? If the register is non-existent and >>> doesn't abort, you could detect this instead. >> >> I'm not sure if we should ever try to write to a non-existent register though >> the behavior could be different in different platforms. IMHO maximum number of >> outbound regions is a HW property and is best described in device tree. > > AIUI, PCI defines non-existent (config space) registers to return all > 1s. Not sure if this register is in PCI config space or the host SoC bus > (e.g. AXI). It seems PCI bridges get done both ways from what I've seen. All of that is correct for the Host or RC. However here cdns,max-outbound-regions is an endpoint specific property (defined only in cdns-pcie-ep.yaml) and is useful while configuring OB address translation unit for the endpoint to access host memory. Thanks Kishon
