Although the bspec lists several MMIO ranges as "MSLICE," it turns out
that a subset of these are of a "GAM" subclass that has unique rules and
doesn't followed regular mslice steering behavior.
* Xe_HP SDV: GAM ranges must always be steered to 0,0. These
registers share the regular steering control register (0xFDC) with
other steering types
* DG2: GAM ranges must always be steered to 1,0. GAM registers have a
dedicated steering control register (0xFE0) so we can set the value
once at startup and rely on implicit steering. Technically the
hardware default should already be set to 1,0 properly, but it never
hurts to ensure that in the driver.
Bspec: 66534
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Prathap Kumar Valsan <prathap.kumar.valsan@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220916014345.3317739-1-matthew.d.roper@intel.com
Accidental use of a "SLICE" macro where a "SUBSLICE" macro was intended
causes the group ID for steering to be calculated incorrectly on
pre-Xe_HP platforms.
Fixes: 9a92732f04 ("drm/i915/gt: Add general DSS steering iterator to intel_gt_mcr")
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220712220513.3451794-1-matthew.d.roper@intel.com
Although all DSS belong to a single pool on Xe_HP platforms (i.e.,
they're not organized into slices from a topology point of view), we do
still need to pass 'group' and 'instance' targets when steering register
accesses to a specific instance of a per-DSS multicast register. The
rules for how to determine group and instance IDs (which previously used
legacy terms "slice" and "subslice") varies by platform. Some platforms
determine steering by gslice membership, some platforms by cslice
membership, and future platforms may have other rules.
Since looping over each DSS and performing steered unicast register
accesses is a relatively common pattern, let's add a dedicated iteration
macro to handle this (and replace the platform-specific "instdone" loop
we were using previously. This will avoid the calling code needing to
figure out the details about how to obtain steering IDs for a specific
DSS.
Most of the places where we use this new loop are in the GPU errorstate
code at the moment, but we do have some additional features coming in
the future that will also need to loop over each DSS and steer some
register accesses accordingly.
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Matt Atwood <matthew.s.atwood@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220701232006.1016135-1-matthew.d.roper@intel.com
Let's replace the assortment of intel_gt_* and intel_uncore_* functions
that operate on MCR registers with a cleaner set of interfaces:
* intel_gt_mcr_read -- unicast read from specific instance
* intel_gt_mcr_read_any[_fw] -- unicast read from any non-terminated
instance
* intel_gt_mcr_unicast_write -- unicast write to specific instance
* intel_gt_mcr_multicast_write[_fw] -- multicast write to all instances
We'll also replace the historic "slice" and "subslice" terminology with
"group" and "instance" to match the documentation for more recent
platforms; these days MCR steering applies to more types of replication
than just slice/subslice.
v2:
- Reference the new kerneldoc from i915.rst. (Jani)
- Tweak the wording of the documentation for a couple functions to
clarify the difference between "_fw" and non-"_fw" forms.
v3:
- s/read/write/ to fix copy-paste mistake in a couple comments.
(Harish)
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Acked-by: Jani Nikula <jani.nikula@linux.intel.com>
Reviewed-by: Harish Chegondi <harish.chegondi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220615001019.1821989-3-matthew.d.roper@intel.com
Handling of multicast/replicated registers is spread across intel_gt.c
and intel_uncore.c today. As multicast handling and the related
steering logic gets more complicated with the addition of new platforms
and new rules it makes sense to centralize it all in one place.
For now the existing functions have been moved to the new .c/.h as-is.
Function renames and updates to operate in a more consistent manner will
be done in subsequent patches.
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Acked-by: Jani Nikula <jani.nikula@linux.intel.com>
Reviewed-by: Harish Chegondi <harish.chegondi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220615001019.1821989-2-matthew.d.roper@intel.com
