drm/i915/icl: Configure DSI Dual link mode

This patch configures DSI video mode dual link by
programming DSS_CTL registers.

v2: Use new bitfield definitions from Anusha's patch
    Correct register to be programmed and use max
    depth buffer value (James)

v3 by Jani:
 - checkpatch fixes

Signed-off-by: Madhav Chauhan <madhav.chauhan@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/d8962f4e1beffc2099b8bef8cb5a5191aa1d9efd.1543500286.git.jani.nikula@intel.com

diff --git a/drivers/gpu/drm/i915/icl_dsi.c b/drivers/gpu/drm/i915/icl_dsi.c
index f935008ff9609d94a2ca31c95ebe3e1d33e4c498..2b576a70222f11b10dd823dd5aacd303e53256b8 100644 (file)
--- a/drivers/gpu/drm/i915/icl_dsi.c
+++ b/drivers/gpu/drm/i915/icl_dsi.c
@@ -257,6 +257,45 @@ static void dsi_program_swing_and_deemphasis(struct intel_encoder *encoder)
        }
 }
 
+static void configure_dual_link_mode(struct intel_encoder *encoder,
+                                    const struct intel_crtc_state *pipe_config)
+{
+       struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
+       struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
+       u32 dss_ctl1;
+
+       dss_ctl1 = I915_READ(DSS_CTL1);
+       dss_ctl1 |= SPLITTER_ENABLE;
+       dss_ctl1 &= ~OVERLAP_PIXELS_MASK;
+       dss_ctl1 |= OVERLAP_PIXELS(intel_dsi->pixel_overlap);
+
+       if (intel_dsi->dual_link == DSI_DUAL_LINK_FRONT_BACK) {
+               const struct drm_display_mode *adjusted_mode =
+                                       &pipe_config->base.adjusted_mode;
+               u32 dss_ctl2;
+               u16 hactive = adjusted_mode->crtc_hdisplay;
+               u16 dl_buffer_depth;
+
+               dss_ctl1 &= ~DUAL_LINK_MODE_INTERLEAVE;
+               dl_buffer_depth = hactive / 2 + intel_dsi->pixel_overlap;
+
+               if (dl_buffer_depth > MAX_DL_BUFFER_TARGET_DEPTH)
+                       DRM_ERROR("DL buffer depth exceed max value\n");
+
+               dss_ctl1 &= ~LEFT_DL_BUF_TARGET_DEPTH_MASK;
+               dss_ctl1 |= LEFT_DL_BUF_TARGET_DEPTH(dl_buffer_depth);
+               dss_ctl2 = I915_READ(DSS_CTL2);
+               dss_ctl2 &= ~RIGHT_DL_BUF_TARGET_DEPTH_MASK;
+               dss_ctl2 |= RIGHT_DL_BUF_TARGET_DEPTH(dl_buffer_depth);
+               I915_WRITE(DSS_CTL2, dss_ctl2);
+       } else {
+               /* Interleave */
+               dss_ctl1 |= DUAL_LINK_MODE_INTERLEAVE;
+       }
+
+       I915_WRITE(DSS_CTL1, dss_ctl1);
+}
+
 static void gen11_dsi_program_esc_clk_div(struct intel_encoder *encoder)
 {
        struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
@@ -591,7 +630,8 @@ gen11_dsi_configure_transcoder(struct intel_encoder *encoder,
                        I915_WRITE(TRANS_DDI_FUNC_CTL2(dsi_trans), tmp);
                }
 
-               //TODO: configure DSS_CTL1
+               /* configure stream splitting */
+               configure_dual_link_mode(encoder, pipe_config);
        }
 
        for_each_dsi_port(port, intel_dsi->ports) {