drm/i915/chv: Use RMW to toggle swing calc init

The spec only tells us to set individual bits here and there. So we use
RMW for most things. Do the same for the swing calc init.

Eventually we should optimize things to just blast the final value in
with group access whenever possible. But to do that someone needs to
take a good look at what's the reset value for each registers, and
possibly if the BIOS manages to frob with some of them. For now
use RMW access always.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_reg.h

@@ -703,6 +703,13 @@ enum punit_power_well {
 #define   DPIO_PCS_SWING_CALC_TX1_TX3	(1<<31)
 #define CHV_PCS_DW10(ch) _PORT(ch, _CHV_PCS_DW10_CH0, _CHV_PCS_DW10_CH1)
 
+#define _VLV_PCS01_DW10_CH0		0x0228
+#define _VLV_PCS23_DW10_CH0		0x0428
+#define _VLV_PCS01_DW10_CH1		0x2628
+#define _VLV_PCS23_DW10_CH1		0x2828
+#define VLV_PCS01_DW10(port) _PORT(port, _VLV_PCS01_DW10_CH0, _VLV_PCS01_DW10_CH1)
+#define VLV_PCS23_DW10(port) _PORT(port, _VLV_PCS23_DW10_CH0, _VLV_PCS23_DW10_CH1)
+
 #define _VLV_PCS_DW11_CH0		0x822c
 #define _VLV_PCS_DW11_CH1		0x842c
 #define VLV_PCS_DW11(ch) _PORT(ch, _VLV_PCS_DW11_CH0, _VLV_PCS_DW11_CH1)

drivers/gpu/drm/i915/intel_dp.c

@@ -2390,7 +2390,13 @@ static uint32_t intel_chv_signal_levels(struct intel_dp *intel_dp)
 	mutex_lock(&dev_priv->dpio_lock);
 
 	/* Clear calc init */
-	vlv_dpio_write(dev_priv, pipe, CHV_PCS_DW10(ch), 0);
+	val = vlv_dpio_read(dev_priv, pipe, VLV_PCS01_DW10(ch));
+	val &= ~(DPIO_PCS_SWING_CALC_TX0_TX2 | DPIO_PCS_SWING_CALC_TX1_TX3);
+	vlv_dpio_write(dev_priv, pipe, VLV_PCS01_DW10(ch), val);
+
+	val = vlv_dpio_read(dev_priv, pipe, VLV_PCS23_DW10(ch));
+	val &= ~(DPIO_PCS_SWING_CALC_TX0_TX2 | DPIO_PCS_SWING_CALC_TX1_TX3);
+	vlv_dpio_write(dev_priv, pipe, VLV_PCS23_DW10(ch), val);
 
 	/* Program swing deemph */
 	for (i = 0; i < 4; i++) {
@@ -2441,8 +2447,13 @@ static uint32_t intel_chv_signal_levels(struct intel_dp *intel_dp)
 	}
 
 	/* Start swing calculation */
-	vlv_dpio_write(dev_priv, pipe, CHV_PCS_DW10(ch),
-		(DPIO_PCS_SWING_CALC_TX0_TX2 | DPIO_PCS_SWING_CALC_TX1_TX3));
+	val = vlv_dpio_read(dev_priv, pipe, VLV_PCS01_DW10(ch));
+	val |= DPIO_PCS_SWING_CALC_TX0_TX2 | DPIO_PCS_SWING_CALC_TX1_TX3;
+	vlv_dpio_write(dev_priv, pipe, VLV_PCS01_DW10(ch), val);
+
+	val = vlv_dpio_read(dev_priv, pipe, VLV_PCS23_DW10(ch));
+	val |= DPIO_PCS_SWING_CALC_TX0_TX2 | DPIO_PCS_SWING_CALC_TX1_TX3;
+	vlv_dpio_write(dev_priv, pipe, VLV_PCS23_DW10(ch), val);
 
 	/* LRC Bypass */
 	val = vlv_dpio_read(dev_priv, pipe, CHV_CMN_DW30);

drivers/gpu/drm/i915/intel_hdmi.c

@@ -1326,7 +1326,13 @@ static void chv_hdmi_pre_enable(struct intel_encoder *encoder)
 	/* FIXME: Fix up value only after power analysis */
 
 	/* Clear calc init */
-	vlv_dpio_write(dev_priv, pipe, CHV_PCS_DW10(ch), 0);
+	val = vlv_dpio_read(dev_priv, pipe, VLV_PCS01_DW10(ch));
+	val &= ~(DPIO_PCS_SWING_CALC_TX0_TX2 | DPIO_PCS_SWING_CALC_TX1_TX3);
+	vlv_dpio_write(dev_priv, pipe, VLV_PCS01_DW10(ch), val);
+
+	val = vlv_dpio_read(dev_priv, pipe, VLV_PCS23_DW10(ch));
+	val &= ~(DPIO_PCS_SWING_CALC_TX0_TX2 | DPIO_PCS_SWING_CALC_TX1_TX3);
+	vlv_dpio_write(dev_priv, pipe, VLV_PCS23_DW10(ch), val);
 
 	/* FIXME: Program the support xxx V-dB */
 	/* Use 800mV-0dB */
@@ -1365,9 +1371,13 @@ static void chv_hdmi_pre_enable(struct intel_encoder *encoder)
 				(0x9a << DPIO_UNIQ_TRANS_SCALE_SHIFT));
 #endif
 	/* Start swing calculation */
-	vlv_dpio_write(dev_priv, pipe, CHV_PCS_DW10(ch),
-			DPIO_PCS_SWING_CALC_TX0_TX2 |
-			DPIO_PCS_SWING_CALC_TX1_TX3);
+	val = vlv_dpio_read(dev_priv, pipe, VLV_PCS01_DW10(ch));
+	val |= DPIO_PCS_SWING_CALC_TX0_TX2 | DPIO_PCS_SWING_CALC_TX1_TX3;
+	vlv_dpio_write(dev_priv, pipe, VLV_PCS01_DW10(ch), val);
+
+	val = vlv_dpio_read(dev_priv, pipe, VLV_PCS23_DW10(ch));
+	val |= DPIO_PCS_SWING_CALC_TX0_TX2 | DPIO_PCS_SWING_CALC_TX1_TX3;
+	vlv_dpio_write(dev_priv, pipe, VLV_PCS23_DW10(ch), val);
 
 	/* LRC Bypass */
 	val = vlv_dpio_read(dev_priv, pipe, CHV_CMN_DW30);