On Thu, Apr 6, 2023 at 11:39 AM Stefan Wahren <stefan.wahren@xxxxxxxx> wrote: > > Hi Jim, > > Am 06.04.23 um 14:46 schrieb Jim Quinlan: > > 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# > > not sure about this, but maybe we should avoid references to Linux > kernel config parameter in a DT binding. Since the driver already gaves > warning in case the DT parameter is present, but kernel config doesn't > fit, this should be enough. Hello Stefan, I will remove this reference. > > > + assertion to clock active must be within 400ns. > > + type: boolean > > + > > + brcm,completion-timeout-msecs: > > + description: Number of msecs before completion timeout > > + abort occurs. > > + $ref: /schemas/types.yaml#/definitions/uint32 > > According to the driver at least 0 is not allowed, maybe we should > define minimum and maximum here and let dtbs_check take care of invalid > values? I'm not sure I follow what you mean about a zero value; the property may have any value but the driver will clamp it to a minimum of ~30msec. Regardless, I can add a "minimum: 30" line to the YAML. Thanks, Jim Quinlan Broadcom STB > > Best regards > > > + > > brcm,scb-sizes: > > description: u64 giving the 64bit PCIe memory > > viewport size of a memory controller. There may be up to
