drm/i915/gen12: Update combo PHY init sequence

The bspec was updated with a minor change to the 'DCC mode select'
setting to be programmed during combo PHY initialization.

v2:
 - Keep the opencoded rmw behavior instead of switching to
   intel_de_rmw().  We need to read from a _LN register, but write to
   the _GRP register to update all lanes.

Bspec: 49291
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/20230221201836.2886794-1-matthew.d.roper@intel.com

drivers/gpu/drm/i915/display/intel_combo_phy.c

@@ -233,8 +233,7 @@ static bool icl_combo_phy_verify_state(struct drm_i915_private *dev_priv,
 				     ICL_PORT_TX_DW8_ODCC_CLK_DIV_SEL_DIV2);
 
 		ret &= check_phy_reg(dev_priv, phy, ICL_PORT_PCS_DW1_LN(0, phy),
-				     DCC_MODE_SELECT_MASK,
-				     DCC_MODE_SELECT_CONTINUOSLY);
+				     DCC_MODE_SELECT_MASK, RUN_DCC_ONCE);
 	}
 
 	ret &= icl_verify_procmon_ref_values(dev_priv, phy);
@@ -354,7 +353,7 @@ static void icl_combo_phys_init(struct drm_i915_private *dev_priv)
 
 			val = intel_de_read(dev_priv, ICL_PORT_PCS_DW1_LN(0, phy));
 			val &= ~DCC_MODE_SELECT_MASK;
-			val |= DCC_MODE_SELECT_CONTINUOSLY;
+			val |= RUN_DCC_ONCE;
 			intel_de_write(dev_priv, ICL_PORT_PCS_DW1_GRP(phy), val);
 		}
 

drivers/gpu/drm/i915/display/intel_combo_phy_regs.h

@@ -90,8 +90,8 @@
 #define ICL_PORT_PCS_DW1_AUX(phy)		_MMIO(_ICL_PORT_PCS_DW_AUX(1, phy))
 #define ICL_PORT_PCS_DW1_GRP(phy)		_MMIO(_ICL_PORT_PCS_DW_GRP(1, phy))
 #define ICL_PORT_PCS_DW1_LN(ln, phy)		_MMIO(_ICL_PORT_PCS_DW_LN(1, ln, phy))
-#define   DCC_MODE_SELECT_MASK			(0x3 << 20)
-#define   DCC_MODE_SELECT_CONTINUOSLY		(0x3 << 20)
+#define   DCC_MODE_SELECT_MASK			REG_GENMASK(21, 20)
+#define   RUN_DCC_ONCE				REG_FIELD_PREP(DCC_MODE_SELECT_MASK, 0)
 #define   COMMON_KEEPER_EN			(1 << 26)
 #define   LATENCY_OPTIM_MASK			(0x3 << 2)
 #define   LATENCY_OPTIM_VAL(x)			((x) << 2)