drm/xe/xelp: L3 recommended hashing mask

According to the i915 codebase xe missed to set the recommended
performance tuning for L3 hashing which is applicable to all legacy XeLP
platforms. Lets add it.

v2:
 * Rename prefixes to XELP_.
 * Tweak version end point.

v3:
 * Add bspec tag.
 * Tweak version range.

v4:
 * Move from LRC to engine tunings list.

v5:
 * Drop L3 Cache Control comment.

Bspec: 31870
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
References: c46c5fb ("drm/i915/gen12: Apply recommended L3 hashing mask")
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250227101304.46660-5-tvrtko.ursulin@igalia.com
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>

Author: Tvrtko Ursulin

drivers/gpu/drm/xe/regs/xe_gt_regs.h

@@ -364,10 +364,12 @@
 #define FORCEWAKE_MEDIA_VEBOX(n)		XE_REG(0xa560 + (n) * 4)
 #define FORCEWAKE_GSC				XE_REG(0xa618)
 
+#define XELP_GARBCNTL				XE_REG(0xb004)
+#define   XELP_BUS_HASH_CTL_BIT_EXC		REG_BIT(7)
+
 #define XEHPC_LNCFMISCCFGREG0			XE_REG_MCR(0xb01c, XE_REG_OPTION_MASKED)
 #define   XEHPC_OVRLSCCC			REG_BIT(0)
 
-/* L3 Cache Control */
 #define LNCFCMOCS_REG_COUNT			32
 #define XELP_LNCFCMOCS(i)			XE_REG(0xb020 + (i) * 4)
 #define XEHP_LNCFCMOCS(i)			XE_REG_MCR(0xb020 + (i) * 4)

drivers/gpu/drm/xe/xe_tuning.c

@@ -88,6 +88,11 @@ static const struct xe_rtp_entry_sr gt_tunings[] = {
 };
 
 static const struct xe_rtp_entry_sr engine_tunings[] = {
+	{ XE_RTP_NAME("Tuning: L3 Hashing Mask"),
+	  XE_RTP_RULES(GRAPHICS_VERSION_RANGE(1200, 1210),
+		       FUNC(xe_rtp_match_first_render_or_compute)),
+	  XE_RTP_ACTIONS(CLR(XELP_GARBCNTL, XELP_BUS_HASH_CTL_BIT_EXC))
+	},
 	{ XE_RTP_NAME("Tuning: Set Indirect State Override"),
 	  XE_RTP_RULES(GRAPHICS_VERSION_RANGE(1200, 1274),
 		       ENGINE_CLASS(RENDER)),