drm/i915/gt: Set CMD_CCTL to UC for Gen12 Onward

Cache-control registers for Command Stream(CMD_CCTL) are used
to set catchability for memory writes and reads outputted by
Command Streamers on Gen12 onward platforms.

These registers need to point un-cached(UC) MOCS index.
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Ayaz A Siddiqui <ayaz.siddiqui@intel.com>
Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210903092153.535736-3-ayaz.siddiqui@intel.com

drivers/gpu/drm/i915/gt/intel_workarounds.c

@@ -1640,6 +1640,31 @@ void intel_engine_apply_whitelist(struct intel_engine_cs *engine)
 				   i915_mmio_reg_offset(RING_NOPID(base)));
 }
 
+/*
+ * engine_fake_wa_init(), a place holder to program the registers
+ * which are not part of an official workaround defined by the
+ * hardware team.
+ * Adding programming of those register inside workaround will
+ * allow utilizing wa framework to proper application and verification.
+ */
+static void
+engine_fake_wa_init(struct intel_engine_cs *engine, struct i915_wa_list *wal)
+{
+	u8 mocs;
+
+	/*
+	 * RING_CMD_CCTL are need to be programed to un-cached
+	 * for memory writes and reads outputted by Command
+	 * Streamers on Gen12 onward platforms.
+	 */
+	if (GRAPHICS_VER(engine->i915) >= 12) {
+		mocs = engine->gt->mocs.uc_index;
+		wa_masked_field_set(wal,
+				    RING_CMD_CCTL(engine->mmio_base),
+				    CMD_CCTL_MOCS_MASK,
+				    CMD_CCTL_MOCS_OVERRIDE(mocs, mocs));
+	}
+}
 static void
 rcs_engine_wa_init(struct intel_engine_cs *engine, struct i915_wa_list *wal)
 {
@@ -2080,6 +2105,8 @@ engine_init_workarounds(struct intel_engine_cs *engine, struct i915_wa_list *wal
 	if (I915_SELFTEST_ONLY(GRAPHICS_VER(engine->i915) < 4))
 		return;
 
+	engine_fake_wa_init(engine, wal);
+
 	if (engine->class == RENDER_CLASS)
 		rcs_engine_wa_init(engine, wal);
 	else

drivers/gpu/drm/i915/i915_reg.h

@@ -2560,6 +2560,23 @@ static inline bool i915_mmio_reg_valid(i915_reg_t reg)
 #define RING_HWS_PGA(base)	_MMIO((base) + 0x80)
 #define RING_ID(base)		_MMIO((base) + 0x8c)
 #define RING_HWS_PGA_GEN6(base)	_MMIO((base) + 0x2080)
+
+#define RING_CMD_CCTL(base)	_MMIO((base) + 0xc4)
+/*
+ * CMD_CCTL read/write fields take a MOCS value and _not_ a table index.
+ * The lsb of each can be considered a separate enabling bit for encryption.
+ * 6:0 == default MOCS value for reads  =>  6:1 == table index for reads.
+ * 13:7 == default MOCS value for writes => 13:8 == table index for writes.
+ * 15:14 == Reserved => 31:30 are set to 0.
+ */
+#define CMD_CCTL_WRITE_OVERRIDE_MASK REG_GENMASK(13, 7)
+#define CMD_CCTL_READ_OVERRIDE_MASK REG_GENMASK(6, 0)
+#define CMD_CCTL_MOCS_MASK (CMD_CCTL_WRITE_OVERRIDE_MASK | \
+			    CMD_CCTL_READ_OVERRIDE_MASK)
+#define CMD_CCTL_MOCS_OVERRIDE(write, read)				      \
+		(REG_FIELD_PREP(CMD_CCTL_WRITE_OVERRIDE_MASK, (write) << 1) | \
+		 REG_FIELD_PREP(CMD_CCTL_READ_OVERRIDE_MASK, (read) << 1))
+
 #define RING_RESET_CTL(base)	_MMIO((base) + 0xd0)
 #define   RESET_CTL_CAT_ERROR	   REG_BIT(2)
 #define   RESET_CTL_READY_TO_RESET REG_BIT(1)