On Fri, Sep 15, 2023 at 03:43:27PM +0200, Konrad Dybcio wrote: > On 14.09.2023 04:32, Mike Tipton wrote: > > On Wed, Sep 13, 2023 at 10:31:49AM +0200, Konrad Dybcio wrote: > >>> The applicable voters should likely be defined in the target-specific > >>> headers, rather than the common qcom,icc.h. The bit range used for them > >>> could be common, but each target may only support a small subset of the > >>> total set of possible voters across all targets. > >> I'm not sure how client drivers would then choose the > >> correct path other than > >> > >> switch (soc) { > >> case 8450: > >> tag = QCOM_ICC_TAG_VOTER_8450_HLOS; > >> break; > >> case 8550: > >> tag = QCOM_ICC_TAG_VOTER_8550_HLOS; > >> break; > >> ... > >> } > >> > >> which would be unacceptable. > > > > The same general way it's handled for the endpoint bindings, which are > > already target-specific. > > > > Any client drivers hardcoding the endpoint bindings in their driver > > would have to include the appropriate, target-specific binding header > > (e.g. qcom,sm8550-rpmh.h). That would only be possible if their driver > > file is itself target-specific. Otherwise, it would have to pull the > > endpoint bindings from devicetree. Or just use the recommended > > of_icc_get() and let devicetree do everything for them. Same for the > > target-specific voter tag bindings. > > > > Clients can also specify their tags in devicetree. They don't actually > > have to call icc_set_tag() directly. For example: > > > > #include <dt-bindings/interconnect/qcom,sm8450.h> > > > > interconnects = <&mmss_noc MASTER_MDP QCOM_ICC_TAG_VOTER_DISP > > &mc_virt SLAVE_EBI1 QCOM_ICC_TAG_VOTER_DISP>; > > > > Then when they call of_icc_get() for this path it'll automatically have > > QCOM_ICC_TAG_VOTER_DISP set for them. > I think I'd skew towards the "define everything in the DT" approach. > > One thing that makes me uneasy to go on with this approach is the > question whether there is a case in which we would want to switch > from e.g. voting through DISP to voting through APPS (or similar) > from within a single device. It shouldn't be common. But it could be done fairly simply by listing paths for each different voter in the dt properties. interconnects = <&mmss_noc MASTER_MDP QCOM_ICC_TAG_VOTER_APPS &mc_virt SLAVE_EBI1 QCOM_ICC_TAG_VOTER_APPS>, <&mmss_noc MASTER_MDP QCOM_ICC_TAG_VOTER_DISP &mc_virt SLAVE_EBI1 QCOM_ICC_TAG_VOTER_DISP>, interconnect-names = "path-apps-voter", "path-disp-voter";