drm/xe/wa: Apply tile workarounds at probe/resume

Although the vast majority of workarounds the driver needs to implement
are either GT-based or display-based, there are occasionally workarounds
that reside outside those parts of the hardware (i.e., in they target
registers in the sgunit/soc); we can consider these to be "tile"
workarounds since there will be instance of these registers per tile.
The registers in question should only lose their values during a
function-level reset, so they only need to be applied during probe and
resume; the registers will not be affected by GT/engine resets.

Tile workarounds are rare (there's only one, 22010954014, that's
relevant to Xe at the moment) so it's probably not worth updating the
xe_rtp design to handle tile-level workarounds yet, although we may want
to consider that in the future if/when more of these show up on future
platforms.

Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Link: https://lore.kernel.org/r/20230913231411.291933-13-matthew.d.roper@intel.com
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/drivers/gpu/drm/xe/xe_wa.c b/drivers/gpu/drm/xe/xe_wa.c
index f45e9452ba0e..d84e67a9af07 100644
--- a/drivers/gpu/drm/xe/xe_wa.c
+++ b/drivers/gpu/drm/xe/xe_wa.c
@@ -753,3 +753,23 @@ void xe_wa_dump(struct xe_gt *gt, struct drm_printer *p)
 		if (oob_was[idx].name)
 			drm_printf_indent(p, 1, "%s\n", oob_was[idx].name);
 }
+
+/*
+ * Apply tile (non-GT, non-display) workarounds.  Think very carefully before
+ * adding anything to this function; most workarounds should be implemented
+ * elsewhere.  The programming here is primarily for sgunit/soc workarounds,
+ * which are relatively rare.  Since the registers these workarounds target are
+ * outside the GT, they should only need to be applied once at device
+ * probe/resume; they will not lose their values on any kind of GT or engine
+ * reset.
+ *
+ * TODO:  We may want to move this over to xe_rtp in the future once we have
+ * enough workarounds to justify the work.
+ */
+void xe_wa_apply_tile_workarounds(struct xe_tile *tile)
+{
+	struct xe_gt *mmio = tile->primary_gt;
+
+	if (XE_WA(mmio, 22010954014))
+		xe_mmio_rmw32(mmio, XEHP_CLOCK_GATE_DIS, 0, SGSI_SIDECLK_DIS);
+}