+static void chv_dp_pre_pll_enable(struct intel_encoder *encoder)
+{
+ struct intel_digital_port *dport = enc_to_dig_port(&encoder->base);
+ struct drm_device *dev = encoder->base.dev;
+ struct drm_i915_private *dev_priv = dev->dev_private;
+ struct intel_crtc *intel_crtc =
+ to_intel_crtc(encoder->base.crtc);
+ enum dpio_channel ch = vlv_dport_to_channel(dport);
+ enum pipe pipe = intel_crtc->pipe;
+ u32 val;
+
+ mutex_lock(&dev_priv->dpio_lock);
+
+ /* program left/right clock distribution */
+ if (pipe != PIPE_B) {
+ val = vlv_dpio_read(dev_priv, pipe, _CHV_CMN_DW5_CH0);
+ val &= ~(CHV_BUFLEFTENA1_MASK | CHV_BUFRIGHTENA1_MASK);
+ if (ch == DPIO_CH0)
+ val |= CHV_BUFLEFTENA1_FORCE;
+ if (ch == DPIO_CH1)
+ val |= CHV_BUFRIGHTENA1_FORCE;
+ vlv_dpio_write(dev_priv, pipe, _CHV_CMN_DW5_CH0, val);
+ } else {
+ val = vlv_dpio_read(dev_priv, pipe, _CHV_CMN_DW1_CH1);
+ val &= ~(CHV_BUFLEFTENA2_MASK | CHV_BUFRIGHTENA2_MASK);
+ if (ch == DPIO_CH0)
+ val |= CHV_BUFLEFTENA2_FORCE;
+ if (ch == DPIO_CH1)
+ val |= CHV_BUFRIGHTENA2_FORCE;
+ vlv_dpio_write(dev_priv, pipe, _CHV_CMN_DW1_CH1, val);
+ }
+
+ /* program clock channel usage */
+ val = vlv_dpio_read(dev_priv, pipe, VLV_PCS01_DW8(ch));
+ val |= CHV_PCS_USEDCLKCHANNEL_OVRRIDE;
+ if (pipe != PIPE_B)
+ val &= ~CHV_PCS_USEDCLKCHANNEL;
+ else
+ val |= CHV_PCS_USEDCLKCHANNEL;
+ vlv_dpio_write(dev_priv, pipe, VLV_PCS01_DW8(ch), val);
+
+ val = vlv_dpio_read(dev_priv, pipe, VLV_PCS23_DW8(ch));
+ val |= CHV_PCS_USEDCLKCHANNEL_OVRRIDE;
+ if (pipe != PIPE_B)
+ val &= ~CHV_PCS_USEDCLKCHANNEL;
+ else
+ val |= CHV_PCS_USEDCLKCHANNEL;
+ vlv_dpio_write(dev_priv, pipe, VLV_PCS23_DW8(ch), val);
+
+ /*
+ * This a a bit weird since generally CL
+ * matches the pipe, but here we need to
+ * pick the CL based on the port.
+ */
+ val = vlv_dpio_read(dev_priv, pipe, CHV_CMN_DW19(ch));
+ if (pipe != PIPE_B)
+ val &= ~CHV_CMN_USEDCLKCHANNEL;
+ else
+ val |= CHV_CMN_USEDCLKCHANNEL;
+ vlv_dpio_write(dev_priv, pipe, CHV_CMN_DW19(ch), val);
+
+ mutex_unlock(&dev_priv->dpio_lock);
+}
+