On Wed, Sep 14, 2022 at 11:00:17AM +0530, Rajendra Nayak wrote: > USB has a requirement to put a performance state vote on 'cx' > while active. Use 'required-opps' to pass this information from > device tree, and since all the GDSCs in GCC (including USB) are > sub-domains of cx, we also add cx as a power-domain for GCC. > Now when any of the consumers of the GDSCs (in this case USB) > votes on a perforamance state, genpd framework can identify that > the GDSC itself does not support a performance state and it > then propogates the vote to the parent, which in this case is cx. > > This change would also mean that any GDSC in GCC thats left enabled > during low power state (perhaps because its marked with a > ALWAYS_ON flag) can prevent the system from entering low power > since that would prevent cx from transitioning to low power. > Ideally any consumers that would need to have their devices > (partially) powered to support wakeups should look at making the > resp. GDSCs transtion to a Retention (PWRSTS_RET) state instead > of leaving them ALWAYS_ON. > > Signed-off-by: Rajendra Nayak <quic_rjendra@xxxxxxxxxxx> > --- > * This patch is a follow up based on the discussion on the previously > posted version to support USB performance state voting [1] > > * Another patch that this approach depends on is the one to fix the > handling of PWRSTS_RET in the GDSC driver [2] so we can have USB > GDSC transtion to a RET state instead of marking it ALWAYS_ON > > [1] https://lore.kernel.org/linux-usb/YTduDqCO9aUyAsw1@ripper/ > [2] https://lore.kernel.org/all/20220901101756.28164-1-quic_rjendra@xxxxxxxxxxx/#t > > arch/arm64/boot/dts/qcom/sc7280.dtsi | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/arch/arm64/boot/dts/qcom/sc7280.dtsi b/arch/arm64/boot/dts/qcom/sc7280.dtsi > index ad04025a8a1a..8a21446738bf 100644 > --- a/arch/arm64/boot/dts/qcom/sc7280.dtsi > +++ b/arch/arm64/boot/dts/qcom/sc7280.dtsi > @@ -828,6 +828,7 @@ > #clock-cells = <1>; > #reset-cells = <1>; > #power-domain-cells = <1>; > + power-domains = <&rpmhpd SC7280_CX>; > }; > > ipcc: mailbox@408000 { > @@ -3456,6 +3457,7 @@ > "ss_phy_irq"; > > power-domains = <&gcc GCC_USB30_PRIM_GDSC>; > + required-opps = <&rpmhpd_opp_svs>; The patch looks really good, but don't you need &rpmhpd_opp_nom for the 200MHz assigned to GCC_USB30_PRIM_MASTER_CLK? Also, how about adding the same to &usb_2, while we're at it? Regards, Bjorn > > resets = <&gcc GCC_USB30_PRIM_BCR>; > > -- > 2.17.1 >
