drm/i915: factor out GMCH panel fitting code and use for eDP v3

This gets the panel fitter working on eDP on VLV, and should also apply
to eDP panels on G4x chipsets (if we ever detect and mark an all-in-one
panel as eDP anyway).

A few cleanups are still possible on top of this, for example the LVDS
border control could be placed in the LVDS encoder structure and updated
based on the result of the panel fitter calculation.

Multi-pipe fitting isn't handled correctly either if we ever get a config
that wants to try the panel fitter on more than one output at a time.

v2: use pipe_config for storing pfit values (Daniel)
    add i9xx_pfit_enable function for use by 9xx and VLV (Daniel)
v3: fixup conflicts and lvds_dither check

Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
[danvet: fix up botched conflict resolution from Jesse:
- border = LVDS_BORDER_ENABLE was lost for CENTER scaling
- comment about gen2/3 panel fitter scaling was lost
- dev_priv->lvds_dither reintroduced.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 191 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index 7f6141d9a06d..0f32f6498ad3 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -117,6 +117,197 @@ done:
         dev_priv->pch_pf_size = (width << 16) | height;
 }
 
+static void
+centre_horizontally(struct drm_display_mode *mode,
+                    int width)
+{
+        u32 border, sync_pos, blank_width, sync_width;
+
+        /* keep the hsync and hblank widths constant */
+        sync_width = mode->crtc_hsync_end - mode->crtc_hsync_start;
+        blank_width = mode->crtc_hblank_end - mode->crtc_hblank_start;
+        sync_pos = (blank_width - sync_width + 1) / 2;
+
+        border = (mode->hdisplay - width + 1) / 2;
+        border += border & 1; /* make the border even */
+
+        mode->crtc_hdisplay = width;
+        mode->crtc_hblank_start = width + border;
+        mode->crtc_hblank_end = mode->crtc_hblank_start + blank_width;
+
+        mode->crtc_hsync_start = mode->crtc_hblank_start + sync_pos;
+        mode->crtc_hsync_end = mode->crtc_hsync_start + sync_width;
+}
+
+static void
+centre_vertically(struct drm_display_mode *mode,
+                  int height)
+{
+        u32 border, sync_pos, blank_width, sync_width;
+
+        /* keep the vsync and vblank widths constant */
+        sync_width = mode->crtc_vsync_end - mode->crtc_vsync_start;
+        blank_width = mode->crtc_vblank_end - mode->crtc_vblank_start;
+        sync_pos = (blank_width - sync_width + 1) / 2;
+
+        border = (mode->vdisplay - height + 1) / 2;
+
+        mode->crtc_vdisplay = height;
+        mode->crtc_vblank_start = height + border;
+        mode->crtc_vblank_end = mode->crtc_vblank_start + blank_width;
+
+        mode->crtc_vsync_start = mode->crtc_vblank_start + sync_pos;
+        mode->crtc_vsync_end = mode->crtc_vsync_start + sync_width;
+}
+
+static inline u32 panel_fitter_scaling(u32 source, u32 target)
+{
+        /*
+         * Floating point operation is not supported. So the FACTOR
+         * is defined, which can avoid the floating point computation
+         * when calculating the panel ratio.
+         */
+#define ACCURACY 12
+#define FACTOR (1 << ACCURACY)
+        u32 ratio = source * FACTOR / target;
+        return (FACTOR * ratio + FACTOR/2) / FACTOR;
+}
+
+void intel_gmch_panel_fitting(struct intel_crtc *intel_crtc,
+                              struct intel_crtc_config *pipe_config,
+                              int fitting_mode)
+{
+        struct drm_device *dev = intel_crtc->base.dev;
+        struct drm_i915_private *dev_priv = dev->dev_private;
+        u32 pfit_control = 0, pfit_pgm_ratios = 0, border = 0;
+        struct drm_display_mode *mode, *adjusted_mode;
+
+        mode = &pipe_config->requested_mode;
+        adjusted_mode = &pipe_config->adjusted_mode;
+
+        /* Native modes don't need fitting */
+        if (adjusted_mode->hdisplay == mode->hdisplay &&
+            adjusted_mode->vdisplay == mode->vdisplay)
+                goto out;
+
+        switch (fitting_mode) {
+        case DRM_MODE_SCALE_CENTER:
+                /*
+                 * For centered modes, we have to calculate border widths &
+                 * heights and modify the values programmed into the CRTC.
+                 */
+                centre_horizontally(adjusted_mode, mode->hdisplay);
+                centre_vertically(adjusted_mode, mode->vdisplay);
+                border = LVDS_BORDER_ENABLE;
+                break;
+        case DRM_MODE_SCALE_ASPECT:
+                /* Scale but preserve the aspect ratio */
+                if (INTEL_INFO(dev)->gen >= 4) {
+                        u32 scaled_width = adjusted_mode->hdisplay *
+                                mode->vdisplay;
+                        u32 scaled_height = mode->hdisplay *
+                                adjusted_mode->vdisplay;
+
+                        /* 965+ is easy, it does everything in hw */
+                        if (scaled_width > scaled_height)
+                                pfit_control |= PFIT_ENABLE |
+                                        PFIT_SCALING_PILLAR;
+                        else if (scaled_width < scaled_height)
+                                pfit_control |= PFIT_ENABLE |
+                                        PFIT_SCALING_LETTER;
+                        else if (adjusted_mode->hdisplay != mode->hdisplay)
+                                pfit_control |= PFIT_ENABLE | PFIT_SCALING_AUTO;
+                } else {
+                        u32 scaled_width = adjusted_mode->hdisplay *
+                                mode->vdisplay;
+                        u32 scaled_height = mode->hdisplay *
+                                adjusted_mode->vdisplay;
+                        /*
+                         * For earlier chips we have to calculate the scaling
+                         * ratio by hand and program it into the
+                         * PFIT_PGM_RATIO register
+                         */
+                        if (scaled_width > scaled_height) { /* pillar */
+                                centre_horizontally(adjusted_mode,
+                                                    scaled_height /
+                                                    mode->vdisplay);
+
+                                border = LVDS_BORDER_ENABLE;
+                                if (mode->vdisplay != adjusted_mode->vdisplay) {
+                                        u32 bits = panel_fitter_scaling(mode->vdisplay, adjusted_mode->vdisplay);
+                                        pfit_pgm_ratios |= (bits << PFIT_HORIZ_SCALE_SHIFT |
+                                                            bits << PFIT_VERT_SCALE_SHIFT);
+                                        pfit_control |= (PFIT_ENABLE |
+                                                         VERT_INTERP_BILINEAR |
+                                                         HORIZ_INTERP_BILINEAR);
+                                }
+                        } else if (scaled_width < scaled_height) { /* letter */
+                                centre_vertically(adjusted_mode,
+                                                  scaled_width /
+                                                  mode->hdisplay);
+
+                                border = LVDS_BORDER_ENABLE;
+                                if (mode->hdisplay != adjusted_mode->hdisplay) {
+                                        u32 bits = panel_fitter_scaling(mode->hdisplay, adjusted_mode->hdisplay);
+                                        pfit_pgm_ratios |= (bits << PFIT_HORIZ_SCALE_SHIFT |
+                                                            bits << PFIT_VERT_SCALE_SHIFT);
+                                        pfit_control |= (PFIT_ENABLE |
+                                                         VERT_INTERP_BILINEAR |
+                                                         HORIZ_INTERP_BILINEAR);
+                                }
+                        } else {
+                                /* Aspects match, Let hw scale both directions */
+                                pfit_control |= (PFIT_ENABLE |
+                                                 VERT_AUTO_SCALE | HORIZ_AUTO_SCALE |
+                                                 VERT_INTERP_BILINEAR |
+                                                 HORIZ_INTERP_BILINEAR);
+                        }
+                }
+                break;
+        default:
+        case DRM_MODE_SCALE_FULLSCREEN:
+                /*
+                 * Full scaling, even if it changes the aspect ratio.
+                 * Fortunately this is all done for us in hw.
+                 */
+                if (mode->vdisplay != adjusted_mode->vdisplay ||
+                    mode->hdisplay != adjusted_mode->hdisplay) {
+                        pfit_control |= PFIT_ENABLE;
+                        if (INTEL_INFO(dev)->gen >= 4)
+                                pfit_control |= PFIT_SCALING_AUTO;
+                        else
+                                pfit_control |= (VERT_AUTO_SCALE |
+                                                 VERT_INTERP_BILINEAR |
+                                                 HORIZ_AUTO_SCALE |
+                                                 HORIZ_INTERP_BILINEAR);
+                }
+                break;
+        }
+
+        /* 965+ wants fuzzy fitting */
+        /* FIXME: handle multiple panels by failing gracefully */
+        if (INTEL_INFO(dev)->gen >= 4)
+                pfit_control |= ((intel_crtc->pipe << PFIT_PIPE_SHIFT) |
+                                 PFIT_FILTER_FUZZY);
+
+out:
+        if ((pfit_control & PFIT_ENABLE) == 0) {
+                pfit_control = 0;
+                pfit_pgm_ratios = 0;
+        }
+
+        /* Make sure pre-965 set dither correctly for 18bpp panels. */
+        if (INTEL_INFO(dev)->gen < 4 && pipe_config->pipe_bpp == 18)
+                pfit_control |= PANEL_8TO6_DITHER_ENABLE;
+
+        if (pfit_control != pipe_config->pfit_control ||
+            pfit_pgm_ratios != pipe_config->pfit_pgm_ratios) {
+                pipe_config->pfit_control = pfit_control;
+                pipe_config->pfit_pgm_ratios = pfit_pgm_ratios;
+        }
+        dev_priv->lvds_border_bits = border;
+}
+
 static int is_backlight_combination_mode(struct drm_device *dev)
 {
         struct drm_i915_private *dev_priv = dev->dev_private;