drm/i915: Add support for changing LVDS panel fitting using an output property.

Previously the driver would always scale the chosen video mode to fill the
panel.  This adds 1:1 and maintain-aspect-ratio scaling modes.

v2: the drm_calloc/drm_free is replaced by kzalloc/kfree based
on Eric's suggestion.

Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>

2 files changed, 280 insertions, 21 deletions

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 544d5677a2fa..88bf7521405f 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -847,9 +847,25 @@
 #define   HORIZ_INTERP_MASK     (3 << 6)
 #define   HORIZ_AUTO_SCALE      (1 << 5)
 #define   PANEL_8TO6_DITHER_ENABLE (1 << 3)
+#define   PFIT_FILTER_FUZZY     (0 << 24)
+#define   PFIT_SCALING_AUTO     (0 << 26)
+#define   PFIT_SCALING_PROGRAMMED (1 << 26)
+#define   PFIT_SCALING_PILLAR   (2 << 26)
+#define   PFIT_SCALING_LETTER   (3 << 26)
 #define PFIT_PGM_RATIOS 0x61234
 #define   PFIT_VERT_SCALE_MASK                  0xfff00000
 #define   PFIT_HORIZ_SCALE_MASK                 0x0000fff0
+/* Pre-965 */
+#define         PFIT_VERT_SCALE_SHIFT           20
+#define         PFIT_VERT_SCALE_MASK            0xfff00000
+#define         PFIT_HORIZ_SCALE_SHIFT          4
+#define         PFIT_HORIZ_SCALE_MASK           0x0000fff0
+/* 965+ */
+#define         PFIT_VERT_SCALE_SHIFT_965       16
+#define         PFIT_VERT_SCALE_MASK_965        0x1fff0000
+#define         PFIT_HORIZ_SCALE_SHIFT_965      0
+#define         PFIT_HORIZ_SCALE_MASK_965       0x00001fff
+
 #define PFIT_AUTO_RATIOS 0x61238
 
 /* Backlight control */
diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index 345e5055f1c0..f416ead71204 100644
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -39,6 +39,21 @@
 
 #define I915_LVDS "i915_lvds"
 
+/*
+ * the following four scaling options are defined.
+ * #define DRM_MODE_SCALE_NON_GPU       0
+ * #define DRM_MODE_SCALE_FULLSCREEN    1
+ * #define DRM_MODE_SCALE_NO_SCALE      2
+ * #define DRM_MODE_SCALE_ASPECT        3
+ */
+
+/* Private structure for the integrated LVDS support */
+struct intel_lvds_priv {
+        int fitting_mode;
+        u32 pfit_control;
+        u32 pfit_pgm_ratios;
+};
+
 /**
  * Sets the backlight level.
  *
@@ -213,10 +228,24 @@ static bool intel_lvds_mode_fixup(struct drm_encoder *encoder,
                                   struct drm_display_mode *mode,
                                   struct drm_display_mode *adjusted_mode)
 {
+        /*
+         * float point operation is not supported . So the PANEL_RATIO_FACTOR
+         * is defined, which can avoid the float point computation when
+         * calculating the panel ratio.
+         */
+#define PANEL_RATIO_FACTOR 8192
         struct drm_device *dev = encoder->dev;
         struct drm_i915_private *dev_priv = dev->dev_private;
         struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
         struct drm_encoder *tmp_encoder;
+        struct intel_output *intel_output = enc_to_intel_output(encoder);
+        struct intel_lvds_priv *lvds_priv = intel_output->dev_priv;
+        u32 pfit_control = 0, pfit_pgm_ratios = 0;
+        int left_border = 0, right_border = 0, top_border = 0;
+        int bottom_border = 0;
+        bool border = 0;
+        int panel_ratio, desired_ratio, vert_scale, horiz_scale;
+        int horiz_ratio, vert_ratio;
 
         /* Should never happen!! */
         if (!IS_I965G(dev) && intel_crtc->pipe == 0) {
@@ -232,7 +261,9 @@ static bool intel_lvds_mode_fixup(struct drm_encoder *encoder,
                         return false;
                 }
         }
-
+        /* If we don't have a panel mode, there is nothing we can do */
+        if (dev_priv->panel_fixed_mode == NULL)
+                return true;
         /*
          * If we have timings from the BIOS for the panel, put them in
          * to the adjusted mode.  The CRTC will be set up for this mode,
@@ -256,6 +287,191 @@ static bool intel_lvds_mode_fixup(struct drm_encoder *encoder,
                 drm_mode_set_crtcinfo(adjusted_mode, CRTC_INTERLACE_HALVE_V);
         }
 
+        /* Make sure pre-965s set dither correctly */
+        if (!IS_I965G(dev)) {
+                if (dev_priv->panel_wants_dither || dev_priv->lvds_dither)
+                        pfit_control |= PANEL_8TO6_DITHER_ENABLE;
+        }
+
+        /* Native modes don't need fitting */
+        if (adjusted_mode->hdisplay == mode->hdisplay &&
+                        adjusted_mode->vdisplay == mode->vdisplay) {
+                pfit_pgm_ratios = 0;
+                border = 0;
+                goto out;
+        }
+
+        /* 965+ wants fuzzy fitting */
+        if (IS_I965G(dev))
+                pfit_control |= (intel_crtc->pipe << PFIT_PIPE_SHIFT) |
+                                        PFIT_FILTER_FUZZY;
+
+        /*
+         * Deal with panel fitting options. Figure out how to stretch the
+         * image based on its aspect ratio & the current panel fitting mode.
+         */
+        panel_ratio = adjusted_mode->hdisplay * PANEL_RATIO_FACTOR /
+                                adjusted_mode->vdisplay;
+        desired_ratio = mode->hdisplay * PANEL_RATIO_FACTOR /
+                                mode->vdisplay;
+        /*
+         * Enable automatic panel scaling for non-native modes so that they fill
+         * the screen.  Should be enabled before the pipe is enabled, according
+         * to register description and PRM.
+         * Change the value here to see the borders for debugging
+         */
+        I915_WRITE(BCLRPAT_A, 0);
+        I915_WRITE(BCLRPAT_B, 0);
+
+        switch (lvds_priv->fitting_mode) {
+        case DRM_MODE_SCALE_NO_SCALE:
+                /*
+                 * For centered modes, we have to calculate border widths &
+                 * heights and modify the values programmed into the CRTC.
+                 */
+                left_border = (adjusted_mode->hdisplay - mode->hdisplay) / 2;
+                right_border = left_border;
+                if (mode->hdisplay & 1)
+                        right_border++;
+                top_border = (adjusted_mode->vdisplay - mode->vdisplay) / 2;
+                bottom_border = top_border;
+                if (mode->vdisplay & 1)
+                        bottom_border++;
+                /* Set active & border values */
+                adjusted_mode->crtc_hdisplay = mode->hdisplay;
+                adjusted_mode->crtc_hblank_start = mode->hdisplay +
+                                                right_border - 1;
+                adjusted_mode->crtc_hblank_end = adjusted_mode->crtc_htotal -
+                                                left_border - 1;
+                adjusted_mode->crtc_hsync_start =
+                                adjusted_mode->crtc_hblank_start;
+                adjusted_mode->crtc_hsync_end =
+                                adjusted_mode->crtc_hblank_end;
+                adjusted_mode->crtc_vdisplay = mode->vdisplay;
+                adjusted_mode->crtc_vblank_start = mode->vdisplay +
+                                                bottom_border - 1;
+                adjusted_mode->crtc_vblank_end = adjusted_mode->crtc_vtotal -
+                                                top_border - 1;
+                adjusted_mode->crtc_vsync_start =
+                                adjusted_mode->crtc_vblank_start;
+                adjusted_mode->crtc_vsync_end =
+                                adjusted_mode->crtc_vblank_end;
+                border = 1;
+                break;
+        case DRM_MODE_SCALE_ASPECT:
+                /* Scale but preserve the spect ratio */
+                pfit_control |= PFIT_ENABLE;
+                if (IS_I965G(dev)) {
+                        /* 965+ is easy, it does everything in hw */
+                        if (panel_ratio > desired_ratio)
+                                pfit_control |= PFIT_SCALING_PILLAR;
+                        else if (panel_ratio < desired_ratio)
+                                pfit_control |= PFIT_SCALING_LETTER;
+                        else
+                                pfit_control |= PFIT_SCALING_AUTO;
+                } else {
+                        /*
+                         * For earlier chips we have to calculate the scaling
+                         * ratio by hand and program it into the
+                         * PFIT_PGM_RATIO register
+                         */
+                        u32 horiz_bits, vert_bits, bits = 12;
+                        horiz_ratio = mode->hdisplay * PANEL_RATIO_FACTOR/
+                                                adjusted_mode->hdisplay;
+                        vert_ratio = mode->vdisplay * PANEL_RATIO_FACTOR/
+                                                adjusted_mode->vdisplay;
+                        horiz_scale = adjusted_mode->hdisplay *
+                                        PANEL_RATIO_FACTOR / mode->hdisplay;
+                        vert_scale = adjusted_mode->vdisplay *
+                                        PANEL_RATIO_FACTOR / mode->vdisplay;
+
+                        /* retain aspect ratio */
+                        if (panel_ratio > desired_ratio) { /* Pillar */
+                                u32 scaled_width;
+                                scaled_width = mode->hdisplay * vert_scale /
+                                                PANEL_RATIO_FACTOR;
+                                horiz_ratio = vert_ratio;
+                                pfit_control |= (VERT_AUTO_SCALE |
+                                                 VERT_INTERP_BILINEAR |
+                                                 HORIZ_INTERP_BILINEAR);
+                                /* Pillar will have left/right borders */
+                                left_border = (adjusted_mode->hdisplay -
+                                                scaled_width) / 2;
+                                right_border = left_border;
+                                if (mode->hdisplay & 1) /* odd resolutions */
+                                        right_border++;
+                                adjusted_mode->crtc_hdisplay = scaled_width;
+                                adjusted_mode->crtc_hblank_start =
+                                        scaled_width + right_border - 1;
+                                adjusted_mode->crtc_hblank_end =
+                                 adjusted_mode->crtc_htotal - left_border - 1;
+                                adjusted_mode->crtc_hsync_start =
+                                        adjusted_mode->crtc_hblank_start;
+                                adjusted_mode->crtc_hsync_end =
+                                        adjusted_mode->crtc_hblank_end;
+                                border = 1;
+                        } else if (panel_ratio < desired_ratio) { /* letter */
+                                u32 scaled_height = mode->vdisplay *
+                                        horiz_scale / PANEL_RATIO_FACTOR;
+                                vert_ratio = horiz_ratio;
+                                pfit_control |= (HORIZ_AUTO_SCALE |
+                                                 VERT_INTERP_BILINEAR |
+                                                 HORIZ_INTERP_BILINEAR);
+                                /* Letterbox will have top/bottom border */
+                                top_border = (adjusted_mode->vdisplay -
+                                        scaled_height) / 2;
+                                bottom_border = top_border;
+                                if (mode->vdisplay & 1)
+                                        bottom_border++;
+                                adjusted_mode->crtc_vdisplay = scaled_height;
+                                adjusted_mode->crtc_vblank_start =
+                                        scaled_height + bottom_border - 1;
+                                adjusted_mode->crtc_vblank_end =
+                                 adjusted_mode->crtc_vtotal - top_border - 1;
+                                adjusted_mode->crtc_vsync_start =
+                                        adjusted_mode->crtc_vblank_start;
+                                adjusted_mode->crtc_vsync_end =
+                                        adjusted_mode->crtc_vblank_end;
+                                border = 1;
+                        } else {
+                        /* Aspects match, Let hw scale both directions */
+                                pfit_control |= (VERT_AUTO_SCALE |
+                                                 HORIZ_AUTO_SCALE |
+                                                 VERT_INTERP_BILINEAR |
+                                                 HORIZ_INTERP_BILINEAR);
+                        }
+                        horiz_bits = (1 << bits) * horiz_ratio /
+                                        PANEL_RATIO_FACTOR;
+                        vert_bits = (1 << bits) * vert_ratio /
+                                        PANEL_RATIO_FACTOR;
+                        pfit_pgm_ratios =
+                                ((vert_bits << PFIT_VERT_SCALE_SHIFT) &
+                                                PFIT_VERT_SCALE_MASK) |
+                                ((horiz_bits << PFIT_HORIZ_SCALE_SHIFT) &
+                                                PFIT_HORIZ_SCALE_MASK);
+                }
+                break;
+
+        case DRM_MODE_SCALE_FULLSCREEN:
+                /*
+                 * Full scaling, even if it changes the aspect ratio.
+                 * Fortunately this is all done for us in hw.
+                 */
+                pfit_control |= PFIT_ENABLE;
+                if (IS_I965G(dev))
+                        pfit_control |= PFIT_SCALING_AUTO;
+                else
+                        pfit_control |= (VERT_AUTO_SCALE | HORIZ_AUTO_SCALE |
+                                         VERT_INTERP_BILINEAR |
+                                         HORIZ_INTERP_BILINEAR);
+                break;
+        default:
+                break;
+        }
+
+out:
+        lvds_priv->pfit_control = pfit_control;
+        lvds_priv->pfit_pgm_ratios = pfit_pgm_ratios;
         /*
          * XXX: It would be nice to support lower refresh rates on the
          * panels to reduce power consumption, and perhaps match the
@@ -301,8 +517,8 @@ static void intel_lvds_mode_set(struct drm_encoder *encoder,
 {
         struct drm_device *dev = encoder->dev;
         struct drm_i915_private *dev_priv = dev->dev_private;
-        struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
-        u32 pfit_control;
+        struct intel_output *intel_output = enc_to_intel_output(encoder);
+        struct intel_lvds_priv *lvds_priv = intel_output->dev_priv;
 
         /*
          * The LVDS pin pair will already have been turned on in the
@@ -319,22 +535,8 @@ static void intel_lvds_mode_set(struct drm_encoder *encoder,
          * screen.  Should be enabled before the pipe is enabled, according to
          * register description and PRM.
          */
-        if (mode->hdisplay != adjusted_mode->hdisplay ||
-            mode->vdisplay != adjusted_mode->vdisplay)
-                pfit_control = (PFIT_ENABLE | VERT_AUTO_SCALE |
-                                HORIZ_AUTO_SCALE | VERT_INTERP_BILINEAR |
-                                HORIZ_INTERP_BILINEAR);
-        else
-                pfit_control = 0;
-
-        if (!IS_I965G(dev)) {
-                if (dev_priv->panel_wants_dither || dev_priv->lvds_dither)
-                        pfit_control |= PANEL_8TO6_DITHER_ENABLE;
-        }
-        else
-                pfit_control |= intel_crtc->pipe << PFIT_PIPE_SHIFT;
-
-        I915_WRITE(PFIT_CONTROL, pfit_control);
+        I915_WRITE(PFIT_PGM_RATIOS, lvds_priv->pfit_pgm_ratios);
+        I915_WRITE(PFIT_CONTROL, lvds_priv->pfit_control);
 }
 
 /**
@@ -406,6 +608,34 @@ static int intel_lvds_set_property(struct drm_connector *connector,
                                    struct drm_property *property,
                                    uint64_t value)
 {
+        struct drm_device *dev = connector->dev;
+        struct intel_output *intel_output =
+                        to_intel_output(connector);
+
+        if (property == dev->mode_config.scaling_mode_property &&
+                                connector->encoder) {
+                struct drm_crtc *crtc = connector->encoder->crtc;
+                struct intel_lvds_priv *lvds_priv = intel_output->dev_priv;
+                if (value == DRM_MODE_SCALE_NON_GPU) {
+                        DRM_DEBUG_KMS(I915_LVDS,
+                                        "non_GPU property is unsupported\n");
+                        return 0;
+                }
+                if (lvds_priv->fitting_mode == value) {
+                        /* the LVDS scaling property is not changed */
+                        return 0;
+                }
+                lvds_priv->fitting_mode = value;
+                if (crtc && crtc->enabled) {
+                        /*
+                         * If the CRTC is enabled, the display will be changed
+                         * according to the new panel fitting mode.
+                         */
+                        drm_crtc_helper_set_mode(crtc, &crtc->mode,
+                                crtc->x, crtc->y, crtc->fb);
+                }
+        }
+
         return 0;
 }
 
@@ -518,6 +748,7 @@ void intel_lvds_init(struct drm_device *dev)
         struct drm_encoder *encoder;
         struct drm_display_mode *scan; /* *modes, *bios_mode; */
         struct drm_crtc *crtc;
+        struct intel_lvds_priv *lvds_priv;
         u32 lvds;
         int pipe, gpio = GPIOC;
 
@@ -531,7 +762,8 @@ void intel_lvds_init(struct drm_device *dev)
                 gpio = PCH_GPIOC;
         }
 
-        intel_output = kzalloc(sizeof(struct intel_output), GFP_KERNEL);
+        intel_output = kzalloc(sizeof(struct intel_output) +
+                                sizeof(struct intel_lvds_priv), GFP_KERNEL);
         if (!intel_output) {
                 return;
         }
@@ -553,7 +785,18 @@ void intel_lvds_init(struct drm_device *dev)
         connector->interlace_allowed = false;
         connector->doublescan_allowed = false;
 
+        lvds_priv = (struct intel_lvds_priv *)(intel_output + 1);
+        intel_output->dev_priv = lvds_priv;
+        /* create the scaling mode property */
+        drm_mode_create_scaling_mode_property(dev);
+        /*
+         * the initial panel fitting mode will be FULL_SCREEN.
+         */
 
+        drm_connector_attach_property(&intel_output->base,
+                                      dev->mode_config.scaling_mode_property,
+                                      DRM_MODE_SCALE_FULLSCREEN);
+        lvds_priv->fitting_mode = DRM_MODE_SCALE_FULLSCREEN;
         /*
          * LVDS discovery:
          * 1) check for EDID on DDC
@@ -649,5 +892,5 @@ failed:
         if (intel_output->ddc_bus)
                 intel_i2c_destroy(intel_output->ddc_bus);
         drm_connector_cleanup(connector);
-        kfree(connector);
+        kfree(intel_output);
 }