On 06/04/2023 14:46, Jim Quinlan wrote: > Regarding "brcm,enable-l1ss": > > The Broadcom STB/CM PCIe HW -- which is also used by RPi SOCs -- requires > the driver probe to configure one of three clkreq# modes: > > (a) clkreq# driven by the RC > (b) clkreq# driven by the EP for ASPM L0s, L1 > (c) bidirectional clkreq#, as used for L1 Substates (L1SS). > > The HW can tell the difference between (a) and (b), but does not know > when to configure (c). Further, the HW will cause a CPU abort on boot if > guesses wrong regarding the need for (c). So we introduce the boolean > "brcm,enable-l1ss" property to indicate that (c) is desired. This > property is already present in the Raspian version of Linux, but the > driver implementaion that will follow adds more details and discerns > between (a) and (b). > > Regarding "brcm,completion-timeout-msecs" > > Our HW will cause a CPU abort if the L1SS exit time is longer than the > completion abort timeout. We've been asked to make this configurable, so > we are introducing "brcm,completion-abort-msecs". > > Signed-off-by: Jim Quinlan <jim2101024@xxxxxxxxx> > --- > .../devicetree/bindings/pci/brcm,stb-pcie.yaml | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml b/Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml > index 7e15aae7d69e..ef4ccc05b258 100644 > --- a/Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml > +++ b/Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml > @@ -64,6 +64,18 @@ properties: > > aspm-no-l0s: true > > + brcm,enable-l1ss: > + description: Indicates that the downstream device is L1SS > + capable and L1SS is desired, e.g. by setting > + CONFIG_PCIEASPM_POWER_SUPERSAVE=y. Note that CLKREQ# How does CONFIG_PCIEASPM_POWER_SUPERSAVE apply to *BSD? > + assertion to clock active must be within 400ns. > + type: boolean > + > + brcm,completion-timeout-msecs: Use standard unit suffixes. > + description: Number of msecs before completion timeout > + abort occurs. > + $ref: /schemas/types.yaml#/definitions/uint32 > + > brcm,scb-sizes: > description: u64 giving the 64bit PCIe memory > viewport size of a memory controller. There may be up to Best regards, Krzysztof
