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authorPankaj Bharadiya <pankaj.laxminarayan.bharadiya@intel.com>2020-10-20 21:44:25 +0530
committerJani Nikula <jani.nikula@intel.com>2020-10-21 12:21:04 +0300
commitcc2396ff75f2ede0cf24f56de64d0214812e226e (patch)
treee0f380ae9e6b1f20d6d0169d866c51bff58cc743
parent105c9e130e1df764ef2d41e2b35f51bba9c52617 (diff)
drm/i915/display: Add Nearest-neighbor based integer scaling support
Integer scaling (IS) is a nearest-neighbor upscaling technique that simply scales up the existing pixels by an integer (i.e., whole number) multiplier.Nearest-neighbor (NN) interpolation works by filling in the missing color values in the upscaled image with that of the coordinate-mapped nearest source pixel value. Both IS and NN preserve the clarity of the original image. Integer scaling is particularly useful for pixel art games that rely on sharp, blocky images to deliver their distinctive look. Introduce functions to configure the scaler filter coefficients to enable nearest-neighbor filtering. Bspec: 49247 changes since v6: * Trust compiler, remove pointless inline keyword from cnl_coef_tap() & cnl_nearest_filter_coef() functions (Ville) changes since v4: * Make cnl_coef_tap(), cnl_nearest_filter_coef() inline (Uma) changes since v3: * None changes since v2: * Move APIs from 5/5 into this patch. * Change filter programming related function names to cnl_*, move filter select bits related code into inline function (Ville) changes since v1: * Rearrange skl_scaler_setup_nearest_neighbor_filter() to iterate the registers directly instead of the phases and taps (Ville) changes since RFC: * Refine the skl_scaler_setup_nearest_neighbor_filter() logic (Ville) Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Reviewed-by: Uma Shankar <uma.shankar@intel.com> Signed-off-by: Shashank Sharma <shashank.sharma@intel.com> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com> Signed-off-by: Pankaj Bharadiya <pankaj.laxminarayan.bharadiya@intel.com> Signed-off-by: Jani Nikula <jani.nikula@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20201020161427.6941-4-pankaj.laxminarayan.bharadiya@intel.com
-rw-r--r--drivers/gpu/drm/i915/display/intel_display.c99
-rw-r--r--drivers/gpu/drm/i915/display/intel_display.h4
2 files changed, 103 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 6ae085c6b361..e829203befad 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -6289,6 +6289,105 @@ void skl_scaler_disable(const struct intel_crtc_state *old_crtc_state)
skl_detach_scaler(crtc, i);
}
+static int cnl_coef_tap(int i)
+{
+ return i % 7;
+}
+
+static u16 cnl_nearest_filter_coef(int t)
+{
+ return t == 3 ? 0x0800 : 0x3000;
+}
+
+/**
+ * Theory behind setting nearest-neighbor integer scaling:
+ *
+ * 17 phase of 7 taps requires 119 coefficients in 60 dwords per set.
+ * The letter represents the filter tap (D is the center tap) and the number
+ * represents the coefficient set for a phase (0-16).
+ *
+ * +------------+------------------------+------------------------+
+ * |Index value | Data value coeffient 1 | Data value coeffient 2 |
+ * +------------+------------------------+------------------------+
+ * | 00h | B0 | A0 |
+ * +------------+------------------------+------------------------+
+ * | 01h | D0 | C0 |
+ * +------------+------------------------+------------------------+
+ * | 02h | F0 | E0 |
+ * +------------+------------------------+------------------------+
+ * | 03h | A1 | G0 |
+ * +------------+------------------------+------------------------+
+ * | 04h | C1 | B1 |
+ * +------------+------------------------+------------------------+
+ * | ... | ... | ... |
+ * +------------+------------------------+------------------------+
+ * | 38h | B16 | A16 |
+ * +------------+------------------------+------------------------+
+ * | 39h | D16 | C16 |
+ * +------------+------------------------+------------------------+
+ * | 3Ah | F16 | C16 |
+ * +------------+------------------------+------------------------+
+ * | 3Bh | Reserved | G16 |
+ * +------------+------------------------+------------------------+
+ *
+ * To enable nearest-neighbor scaling: program scaler coefficents with
+ * the center tap (Dxx) values set to 1 and all other values set to 0 as per
+ * SCALER_COEFFICIENT_FORMAT
+ *
+ */
+
+static void cnl_program_nearest_filter_coefs(struct drm_i915_private *dev_priv,
+ enum pipe pipe, int id, int set)
+{
+ int i;
+
+ intel_de_write_fw(dev_priv, CNL_PS_COEF_INDEX_SET(pipe, id, set),
+ PS_COEE_INDEX_AUTO_INC);
+
+ for (i = 0; i < 17 * 7; i += 2) {
+ u32 tmp;
+ int t;
+
+ t = cnl_coef_tap(i);
+ tmp = cnl_nearest_filter_coef(t);
+
+ t = cnl_coef_tap(i + 1);
+ tmp |= cnl_nearest_filter_coef(t) << 16;
+
+ intel_de_write_fw(dev_priv, CNL_PS_COEF_DATA_SET(pipe, id, set),
+ tmp);
+ }
+
+ intel_de_write_fw(dev_priv, CNL_PS_COEF_INDEX_SET(pipe, id, set), 0);
+}
+
+inline u32 skl_scaler_get_filter_select(enum drm_scaling_filter filter, int set)
+{
+ if (filter == DRM_SCALING_FILTER_NEAREST_NEIGHBOR) {
+ return (PS_FILTER_PROGRAMMED |
+ PS_Y_VERT_FILTER_SELECT(set) |
+ PS_Y_HORZ_FILTER_SELECT(set) |
+ PS_UV_VERT_FILTER_SELECT(set) |
+ PS_UV_HORZ_FILTER_SELECT(set));
+ }
+
+ return PS_FILTER_MEDIUM;
+}
+
+void skl_scaler_setup_filter(struct drm_i915_private *dev_priv, enum pipe pipe,
+ int id, int set, enum drm_scaling_filter filter)
+{
+ switch (filter) {
+ case DRM_SCALING_FILTER_DEFAULT:
+ break;
+ case DRM_SCALING_FILTER_NEAREST_NEIGHBOR:
+ cnl_program_nearest_filter_coefs(dev_priv, pipe, id, set);
+ break;
+ default:
+ MISSING_CASE(filter);
+ }
+}
+
static void skl_pfit_enable(const struct intel_crtc_state *crtc_state)
{
struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
diff --git a/drivers/gpu/drm/i915/display/intel_display.h b/drivers/gpu/drm/i915/display/intel_display.h
index d10b7c8cde3f..1b946209e06b 100644
--- a/drivers/gpu/drm/i915/display/intel_display.h
+++ b/drivers/gpu/drm/i915/display/intel_display.h
@@ -28,6 +28,7 @@
#include <drm/drm_util.h>
enum link_m_n_set;
+enum drm_scaling_filter;
struct dpll;
struct drm_connector;
struct drm_device;
@@ -599,6 +600,9 @@ void intel_crtc_arm_fifo_underrun(struct intel_crtc *crtc,
u16 skl_scaler_calc_phase(int sub, int scale, bool chroma_center);
void skl_scaler_disable(const struct intel_crtc_state *old_crtc_state);
+u32 skl_scaler_get_filter_select(enum drm_scaling_filter filter, int set);
+void skl_scaler_setup_filter(struct drm_i915_private *dev_priv, enum pipe pipe,
+ int id, int set, enum drm_scaling_filter filter);
void ilk_pfit_disable(const struct intel_crtc_state *old_crtc_state);
u32 glk_plane_color_ctl(const struct intel_crtc_state *crtc_state,
const struct intel_plane_state *plane_state);