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Matt Roper authored
Although most of our multicast registers are replicated per-subslice, we also have a small number of multicast registers that are replicated per-l3 bank instead. For both types of multicast registers we need to make sure we steer reads of these registers to a valid instance. Ideally we'd like to find a specific instance ID that would steer reads of either type of multicast register to a valid instance (i.e., not fused off and not powered down), but sometimes the combination of part-specific fusing and the additional restrictions imposed by Render Power Gating make it impossible to find any overlap between the set of valid subslices and valid l3 banks. This problem will become even more noticeable on our upcoming platforms since they will be adding additional types of multicast registers with new types of replication and rules for finding valid instances for reads. To handle this we'll continue to pick a suitable subslice instance at driver startup and program this as the default (sliceid,subsliceid) setting in the steering control register (0xFDC). In cases where we need to read another type of multicast GT register, but the default subslice steering would not correspond to a valid instance, we'll explicitly re-steer the single read to a valid value, perform the read, and then reset the steering to it's "subslice" default. This patch adds the general functionality to prepare for this explicit steering of other multicast register types. We'll plug L3 bank steering into this in the next patch, and then add additional types of multicast registers when the support for our next upcoming platform arrives. v2: - Use entry->end==0 as table terminator. (Rodrigo) - Grab forcewake in wa_list_verify() now that we're using accessors that assume forcewake is already held. v3: - Fix loop condition when iterating over steering range tables. (Rodrigo) Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Signed-off-by: Matt Roper <matthew.d.roper@intel.com> Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20210617211425.1943662-3-matthew.d.roper@intel.com
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