drm/i915/bdw: add support for BDW DP voltage swings and pre-emphasis

They're not the same as the Haswell ones.

Reviewed-by: Art Runyan <arthur.j.runyan@intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Todd Previte <tprevite@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

2 files changed, 63 insertions, 3 deletions

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 0b7983b87ce8..ad903b927fb8 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -5197,6 +5197,7 @@
 #define DDI_BUF_CTL_B                           0x64100
 #define DDI_BUF_CTL(port) _PORT(port, DDI_BUF_CTL_A, DDI_BUF_CTL_B)
 #define  DDI_BUF_CTL_ENABLE                     (1<<31)
+/* Haswell */
 #define  DDI_BUF_EMP_400MV_0DB_HSW              (0<<24)   /* Sel0 */
 #define  DDI_BUF_EMP_400MV_3_5DB_HSW            (1<<24)   /* Sel1 */
 #define  DDI_BUF_EMP_400MV_6DB_HSW              (2<<24)   /* Sel2 */
@@ -5206,6 +5207,16 @@
 #define  DDI_BUF_EMP_600MV_6DB_HSW              (6<<24)   /* Sel6 */
 #define  DDI_BUF_EMP_800MV_0DB_HSW              (7<<24)   /* Sel7 */
 #define  DDI_BUF_EMP_800MV_3_5DB_HSW            (8<<24)   /* Sel8 */
+/* Broadwell */
+#define  DDI_BUF_EMP_400MV_0DB_BDW              (0<<24)   /* Sel0 */
+#define  DDI_BUF_EMP_400MV_3_5DB_BDW            (1<<24)   /* Sel1 */
+#define  DDI_BUF_EMP_400MV_6DB_BDW              (2<<24)   /* Sel2 */
+#define  DDI_BUF_EMP_600MV_0DB_BDW              (3<<24)   /* Sel3 */
+#define  DDI_BUF_EMP_600MV_3_5DB_BDW            (4<<24)   /* Sel4 */
+#define  DDI_BUF_EMP_600MV_6DB_BDW              (5<<24)   /* Sel5 */
+#define  DDI_BUF_EMP_800MV_0DB_BDW              (6<<24)   /* Sel6 */
+#define  DDI_BUF_EMP_800MV_3_5DB_BDW            (7<<24)   /* Sel7 */
+#define  DDI_BUF_EMP_1200MV_0DB_BDW             (8<<24)   /* Sel8 */
 #define  DDI_BUF_EMP_MASK                       (0xf<<24)
 #define  DDI_BUF_PORT_REVERSAL                  (1<<16)
 #define  DDI_BUF_IS_IDLE                        (1<<7)
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 7619eae35b25..f39856e12094 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1958,7 +1958,7 @@ intel_dp_voltage_max(struct intel_dp *intel_dp)
         struct drm_device *dev = intel_dp_to_dev(intel_dp);
         enum port port = dp_to_dig_port(intel_dp)->port;
 
-        if (IS_VALLEYVIEW(dev))
+        if (IS_VALLEYVIEW(dev) || IS_BROADWELL(dev))
                 return DP_TRAIN_VOLTAGE_SWING_1200;
         else if (IS_GEN7(dev) && port == PORT_A)
                 return DP_TRAIN_VOLTAGE_SWING_800;
@@ -1974,7 +1974,18 @@ intel_dp_pre_emphasis_max(struct intel_dp *intel_dp, uint8_t voltage_swing)
         struct drm_device *dev = intel_dp_to_dev(intel_dp);
         enum port port = dp_to_dig_port(intel_dp)->port;
 
-        if (HAS_DDI(dev)) {
+        if (IS_BROADWELL(dev)) {
+                switch (voltage_swing & DP_TRAIN_VOLTAGE_SWING_MASK) {
+                case DP_TRAIN_VOLTAGE_SWING_400:
+                case DP_TRAIN_VOLTAGE_SWING_600:
+                        return DP_TRAIN_PRE_EMPHASIS_6;
+                case DP_TRAIN_VOLTAGE_SWING_800:
+                        return DP_TRAIN_PRE_EMPHASIS_3_5;
+                case DP_TRAIN_VOLTAGE_SWING_1200:
+                default:
+                        return DP_TRAIN_PRE_EMPHASIS_0;
+                }
+        } else if (IS_HASWELL(dev)) {
                 switch (voltage_swing & DP_TRAIN_VOLTAGE_SWING_MASK) {
                 case DP_TRAIN_VOLTAGE_SWING_400:
                         return DP_TRAIN_PRE_EMPHASIS_9_5;
@@ -2286,6 +2297,41 @@ intel_hsw_signal_levels(uint8_t train_set)
         }
 }
 
+static uint32_t
+intel_bdw_signal_levels(uint8_t train_set)
+{
+        int signal_levels = train_set & (DP_TRAIN_VOLTAGE_SWING_MASK |
+                                         DP_TRAIN_PRE_EMPHASIS_MASK);
+        switch (signal_levels) {
+        case DP_TRAIN_VOLTAGE_SWING_400 | DP_TRAIN_PRE_EMPHASIS_0:
+                return DDI_BUF_EMP_400MV_0DB_BDW;       /* Sel0 */
+        case DP_TRAIN_VOLTAGE_SWING_400 | DP_TRAIN_PRE_EMPHASIS_3_5:
+                return DDI_BUF_EMP_400MV_3_5DB_BDW;     /* Sel1 */
+        case DP_TRAIN_VOLTAGE_SWING_400 | DP_TRAIN_PRE_EMPHASIS_6:
+                return DDI_BUF_EMP_400MV_6DB_BDW;       /* Sel2 */
+
+        case DP_TRAIN_VOLTAGE_SWING_600 | DP_TRAIN_PRE_EMPHASIS_0:
+                return DDI_BUF_EMP_600MV_0DB_BDW;       /* Sel3 */
+        case DP_TRAIN_VOLTAGE_SWING_600 | DP_TRAIN_PRE_EMPHASIS_3_5:
+                return DDI_BUF_EMP_600MV_3_5DB_BDW;     /* Sel4 */
+        case DP_TRAIN_VOLTAGE_SWING_600 | DP_TRAIN_PRE_EMPHASIS_6:
+                return DDI_BUF_EMP_600MV_6DB_BDW;       /* Sel5 */
+
+        case DP_TRAIN_VOLTAGE_SWING_800 | DP_TRAIN_PRE_EMPHASIS_0:
+                return DDI_BUF_EMP_800MV_0DB_BDW;       /* Sel6 */
+        case DP_TRAIN_VOLTAGE_SWING_800 | DP_TRAIN_PRE_EMPHASIS_3_5:
+                return DDI_BUF_EMP_800MV_3_5DB_BDW;     /* Sel7 */
+
+        case DP_TRAIN_VOLTAGE_SWING_1200 | DP_TRAIN_PRE_EMPHASIS_0:
+                return DDI_BUF_EMP_1200MV_0DB_BDW;      /* Sel8 */
+
+        default:
+                DRM_DEBUG_KMS("Unsupported voltage swing/pre-emphasis level:"
+                              "0x%x\n", signal_levels);
+                return DDI_BUF_EMP_400MV_0DB_BDW;       /* Sel0 */
+        }
+}
+
 /* Properly updates "DP" with the correct signal levels. */
 static void
 intel_dp_set_signal_levels(struct intel_dp *intel_dp, uint32_t *DP)
@@ -2296,7 +2342,10 @@ intel_dp_set_signal_levels(struct intel_dp *intel_dp, uint32_t *DP)
         uint32_t signal_levels, mask;
         uint8_t train_set = intel_dp->train_set[0];
 
-        if (HAS_DDI(dev)) {
+        if (IS_BROADWELL(dev)) {
+                signal_levels = intel_bdw_signal_levels(train_set);
+                mask = DDI_BUF_EMP_MASK;
+        } else if (IS_HASWELL(dev)) {
                 signal_levels = intel_hsw_signal_levels(train_set);
                 mask = DDI_BUF_EMP_MASK;
         } else if (IS_VALLEYVIEW(dev)) {