Steering of multicast/replicated registers becomes a bit more complicated on Meteor Lake. Whereas previously the control register we used to manage the steering was only used by our driver[*], software's control of steering has now been consolidated with the controls for various other hardware/firmware agents into a single register. We can no longer utilize pre-programmed implicit steering since other firmware agents may change the steering target and not restore it afterward; we'll need to explicitly steer all types of MCR registers (including the GSLICE/COMPUTE/DSS ranges that have been handled implicitly in the past). Furthermore, since multiple agents will now be sharing a single steering control register, races are possible. To address this, the hardware adds a new MCR semaphore register which is supposed to be used to temporarily lock the steering while performing MCR operations. It's going to become important for us to handle accesses of multicast registers very explicitly going forward. This series provides some prep work for that by updating our register definitions to clearly define registers as either MCR or non-MCR and ensure that we're using the intel_gt_mcr_*() functions rather than intel_uncore_*() when operating on MCR registers. In a future series we plan to change the MCR_REG() register definitions to actually declare MCR registers as a new C type (i.e., not an i915_reg_t) so that the compiler will be able to help us find any mistakes where non-MCR functions are used on MCR registers and vice-versa. Introduction of the MTL steering tables and introduction of the steering semaphore support will also arrive in future patch series. [*] This is a bit of an oversimplification; there are some hardware and software debug tools that use the same MCR_SELECTOR register that i915 does and which could potentially re-steer MCR accesses behind our back. E.g., simply using IGT's "intel_reg" tool to write the MCR_SELECTOR register at the wrong time could interfere with driver operation. But given that these debug facilities require root privileges to run and are only used by people intentionally debugging the driver or hardware, we can ignore such races for real-world usage. Matt Roper (7): drm/i915/gen8: Create separate reg definitions for new MCR registers drm/i915/xehp: Create separate reg definitions for new MCR registers drm/i915/gt: Drop a few unused register definitions drm/i915/gt: Correct prefix on a few registers drm/i915: Define MCR registers explicitly drm/i915/gt: Always use MCR functions on multicast registers drm/i915/gt: Add MCR-specific workaround initializers drivers/gpu/drm/i915/gt/intel_engine_cs.c | 4 +- drivers/gpu/drm/i915/gt/intel_ggtt.c | 4 +- drivers/gpu/drm/i915/gt/intel_gt_regs.h | 138 +++--- drivers/gpu/drm/i915/gt/intel_gtt.c | 44 +- drivers/gpu/drm/i915/gt/intel_gtt.h | 2 +- drivers/gpu/drm/i915/gt/intel_mocs.c | 12 +- drivers/gpu/drm/i915/gt/intel_workarounds.c | 426 +++++++++++------- .../gpu/drm/i915/gt/intel_workarounds_types.h | 4 +- drivers/gpu/drm/i915/gt/uc/intel_guc_ads.c | 7 +- .../gpu/drm/i915/gt/uc/intel_guc_capture.c | 4 +- drivers/gpu/drm/i915/gt/uc/intel_guc_fw.c | 12 +- drivers/gpu/drm/i915/gvt/handlers.c | 2 +- drivers/gpu/drm/i915/gvt/mmio_context.c | 2 +- drivers/gpu/drm/i915/intel_gvt_mmio_table.c | 2 +- drivers/gpu/drm/i915/intel_pm.c | 20 +- 15 files changed, 397 insertions(+), 286 deletions(-) -- 2.37.2
