drm/i915: Move dsc rate params compute into drm

The function intel_compute_rc_parameters is part of the dsc spec
and is not driver-specific. Other drm drivers might like to use
it.  The function is not changed; just moved and renamed.
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: David Francis <David.Francis@amd.com>
Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190221202001.28430-2-David.Francis@amd.com

drivers/gpu/drm/drm_dsc.c

@@ -11,6 +11,7 @@
 #include <linux/init.h>
 #include <linux/errno.h>
 #include <linux/byteorder/generic.h>
+#include <drm/drm_print.h>
 #include <drm/drm_dp_helper.h>
 #include <drm/drm_dsc.h>
 
@@ -244,3 +245,137 @@ void drm_dsc_pps_infoframe_pack(struct drm_dsc_pps_infoframe *pps_sdp,
 	/* PPS 94 - 127 are O */
 }
 EXPORT_SYMBOL(drm_dsc_pps_infoframe_pack);
+
+/**
+ * drm_dsc_compute_rc_parameters() - Write rate control
+ * parameters to the dsc configuration defined in
+ * &struct drm_dsc_config in accordance with the DSC 1.1
+ * specification. Some configuration fields must be present
+ * beforehand.
+ *
+ * @vdsc_cfg:
+ * DSC Configuration data partially filled by driver
+ */
+int drm_dsc_compute_rc_parameters(struct drm_dsc_config *vdsc_cfg)
+{
+	unsigned long groups_per_line = 0;
+	unsigned long groups_total = 0;
+	unsigned long num_extra_mux_bits = 0;
+	unsigned long slice_bits = 0;
+	unsigned long hrd_delay = 0;
+	unsigned long final_scale = 0;
+	unsigned long rbs_min = 0;
+
+	/* Number of groups used to code each line of a slice */
+	groups_per_line = DIV_ROUND_UP(vdsc_cfg->slice_width,
+				       DSC_RC_PIXELS_PER_GROUP);
+
+	/* chunksize in Bytes */
+	vdsc_cfg->slice_chunk_size = DIV_ROUND_UP(vdsc_cfg->slice_width *
+						  vdsc_cfg->bits_per_pixel,
+						  (8 * 16));
+
+	if (vdsc_cfg->convert_rgb)
+		num_extra_mux_bits = 3 * (vdsc_cfg->mux_word_size +
+					  (4 * vdsc_cfg->bits_per_component + 4)
+					  - 2);
+	else
+		num_extra_mux_bits = 3 * vdsc_cfg->mux_word_size +
+			(4 * vdsc_cfg->bits_per_component + 4) +
+			2 * (4 * vdsc_cfg->bits_per_component) - 2;
+	/* Number of bits in one Slice */
+	slice_bits = 8 * vdsc_cfg->slice_chunk_size * vdsc_cfg->slice_height;
+
+	while ((num_extra_mux_bits > 0) &&
+	       ((slice_bits - num_extra_mux_bits) % vdsc_cfg->mux_word_size))
+		num_extra_mux_bits--;
+
+	if (groups_per_line < vdsc_cfg->initial_scale_value - 8)
+		vdsc_cfg->initial_scale_value = groups_per_line + 8;
+
+	/* scale_decrement_interval calculation according to DSC spec 1.11 */
+	if (vdsc_cfg->initial_scale_value > 8)
+		vdsc_cfg->scale_decrement_interval = groups_per_line /
+			(vdsc_cfg->initial_scale_value - 8);
+	else
+		vdsc_cfg->scale_decrement_interval = DSC_SCALE_DECREMENT_INTERVAL_MAX;
+
+	vdsc_cfg->final_offset = vdsc_cfg->rc_model_size -
+		(vdsc_cfg->initial_xmit_delay *
+		 vdsc_cfg->bits_per_pixel + 8) / 16 + num_extra_mux_bits;
+
+	if (vdsc_cfg->final_offset >= vdsc_cfg->rc_model_size) {
+		DRM_DEBUG_KMS("FinalOfs < RcModelSze for this InitialXmitDelay\n");
+		return -ERANGE;
+	}
+
+	final_scale = (vdsc_cfg->rc_model_size * 8) /
+		(vdsc_cfg->rc_model_size - vdsc_cfg->final_offset);
+	if (vdsc_cfg->slice_height > 1)
+		/*
+		 * NflBpgOffset is 16 bit value with 11 fractional bits
+		 * hence we multiply by 2^11 for preserving the
+		 * fractional part
+		 */
+		vdsc_cfg->nfl_bpg_offset = DIV_ROUND_UP((vdsc_cfg->first_line_bpg_offset << 11),
+							(vdsc_cfg->slice_height - 1));
+	else
+		vdsc_cfg->nfl_bpg_offset = 0;
+
+	/* 2^16 - 1 */
+	if (vdsc_cfg->nfl_bpg_offset > 65535) {
+		DRM_DEBUG_KMS("NflBpgOffset is too large for this slice height\n");
+		return -ERANGE;
+	}
+
+	/* Number of groups used to code the entire slice */
+	groups_total = groups_per_line * vdsc_cfg->slice_height;
+
+	/* slice_bpg_offset is 16 bit value with 11 fractional bits */
+	vdsc_cfg->slice_bpg_offset = DIV_ROUND_UP(((vdsc_cfg->rc_model_size -
+						    vdsc_cfg->initial_offset +
+						    num_extra_mux_bits) << 11),
+						  groups_total);
+
+	if (final_scale > 9) {
+		/*
+		 * ScaleIncrementInterval =
+		 * finaloffset/((NflBpgOffset + SliceBpgOffset)*8(finalscale - 1.125))
+		 * as (NflBpgOffset + SliceBpgOffset) has 11 bit fractional value,
+		 * we need divide by 2^11 from pstDscCfg values
+		 */
+		vdsc_cfg->scale_increment_interval =
+				(vdsc_cfg->final_offset * (1 << 11)) /
+				((vdsc_cfg->nfl_bpg_offset +
+				vdsc_cfg->slice_bpg_offset) *
+				(final_scale - 9));
+	} else {
+		/*
+		 * If finalScaleValue is less than or equal to 9, a value of 0 should
+		 * be used to disable the scale increment at the end of the slice
+		 */
+		vdsc_cfg->scale_increment_interval = 0;
+	}
+
+	if (vdsc_cfg->scale_increment_interval > 65535) {
+		DRM_DEBUG_KMS("ScaleIncrementInterval is large for slice height\n");
+		return -ERANGE;
+	}
+
+	/*
+	 * DSC spec mentions that bits_per_pixel specifies the target
+	 * bits/pixel (bpp) rate that is used by the encoder,
+	 * in steps of 1/16 of a bit per pixel
+	 */
+	rbs_min = vdsc_cfg->rc_model_size - vdsc_cfg->initial_offset +
+		DIV_ROUND_UP(vdsc_cfg->initial_xmit_delay *
+			     vdsc_cfg->bits_per_pixel, 16) +
+		groups_per_line * vdsc_cfg->first_line_bpg_offset;
+
+	hrd_delay = DIV_ROUND_UP((rbs_min * 16), vdsc_cfg->bits_per_pixel);
+	vdsc_cfg->rc_bits = (hrd_delay * vdsc_cfg->bits_per_pixel) / 16;
+	vdsc_cfg->initial_dec_delay = hrd_delay - vdsc_cfg->initial_xmit_delay;
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_dsc_compute_rc_parameters);

drivers/gpu/drm/i915/intel_vdsc.c

@@ -317,129 +317,6 @@ static int get_column_index_for_rc_params(u8 bits_per_component)
 	}
 }
 
-static int intel_compute_rc_parameters(struct drm_dsc_config *vdsc_cfg)
-{
-	unsigned long groups_per_line = 0;
-	unsigned long groups_total = 0;
-	unsigned long num_extra_mux_bits = 0;
-	unsigned long slice_bits = 0;
-	unsigned long hrd_delay = 0;
-	unsigned long final_scale = 0;
-	unsigned long rbs_min = 0;
-
-	/* Number of groups used to code each line of a slice */
-	groups_per_line = DIV_ROUND_UP(vdsc_cfg->slice_width,
-				       DSC_RC_PIXELS_PER_GROUP);
-
-	/* chunksize in Bytes */
-	vdsc_cfg->slice_chunk_size = DIV_ROUND_UP(vdsc_cfg->slice_width *
-						  vdsc_cfg->bits_per_pixel,
-						  (8 * 16));
-
-	if (vdsc_cfg->convert_rgb)
-		num_extra_mux_bits = 3 * (vdsc_cfg->mux_word_size +
-					  (4 * vdsc_cfg->bits_per_component + 4)
-					  - 2);
-	else
-		num_extra_mux_bits = 3 * vdsc_cfg->mux_word_size +
-			(4 * vdsc_cfg->bits_per_component + 4) +
-			2 * (4 * vdsc_cfg->bits_per_component) - 2;
-	/* Number of bits in one Slice */
-	slice_bits = 8 * vdsc_cfg->slice_chunk_size * vdsc_cfg->slice_height;
-
-	while ((num_extra_mux_bits > 0) &&
-	       ((slice_bits - num_extra_mux_bits) % vdsc_cfg->mux_word_size))
-		num_extra_mux_bits--;
-
-	if (groups_per_line < vdsc_cfg->initial_scale_value - 8)
-		vdsc_cfg->initial_scale_value = groups_per_line + 8;
-
-	/* scale_decrement_interval calculation according to DSC spec 1.11 */
-	if (vdsc_cfg->initial_scale_value > 8)
-		vdsc_cfg->scale_decrement_interval = groups_per_line /
-			(vdsc_cfg->initial_scale_value - 8);
-	else
-		vdsc_cfg->scale_decrement_interval = DSC_SCALE_DECREMENT_INTERVAL_MAX;
-
-	vdsc_cfg->final_offset = vdsc_cfg->rc_model_size -
-		(vdsc_cfg->initial_xmit_delay *
-		 vdsc_cfg->bits_per_pixel + 8) / 16 + num_extra_mux_bits;
-
-	if (vdsc_cfg->final_offset >= vdsc_cfg->rc_model_size) {
-		DRM_DEBUG_KMS("FinalOfs < RcModelSze for this InitialXmitDelay\n");
-		return -ERANGE;
-	}
-
-	final_scale = (vdsc_cfg->rc_model_size * 8) /
-		(vdsc_cfg->rc_model_size - vdsc_cfg->final_offset);
-	if (vdsc_cfg->slice_height > 1)
-		/*
-		 * NflBpgOffset is 16 bit value with 11 fractional bits
-		 * hence we multiply by 2^11 for preserving the
-		 * fractional part
-		 */
-		vdsc_cfg->nfl_bpg_offset = DIV_ROUND_UP((vdsc_cfg->first_line_bpg_offset << 11),
-							(vdsc_cfg->slice_height - 1));
-	else
-		vdsc_cfg->nfl_bpg_offset = 0;
-
-	/* 2^16 - 1 */
-	if (vdsc_cfg->nfl_bpg_offset > 65535) {
-		DRM_DEBUG_KMS("NflBpgOffset is too large for this slice height\n");
-		return -ERANGE;
-	}
-
-	/* Number of groups used to code the entire slice */
-	groups_total = groups_per_line * vdsc_cfg->slice_height;
-
-	/* slice_bpg_offset is 16 bit value with 11 fractional bits */
-	vdsc_cfg->slice_bpg_offset = DIV_ROUND_UP(((vdsc_cfg->rc_model_size -
-						    vdsc_cfg->initial_offset +
-						    num_extra_mux_bits) << 11),
-						  groups_total);
-
-	if (final_scale > 9) {
-		/*
-		 * ScaleIncrementInterval =
-		 * finaloffset/((NflBpgOffset + SliceBpgOffset)*8(finalscale - 1.125))
-		 * as (NflBpgOffset + SliceBpgOffset) has 11 bit fractional value,
-		 * we need divide by 2^11 from pstDscCfg values
-		 */
-		vdsc_cfg->scale_increment_interval =
-				(vdsc_cfg->final_offset * (1 << 11)) /
-				((vdsc_cfg->nfl_bpg_offset +
-				vdsc_cfg->slice_bpg_offset) *
-				(final_scale - 9));
-	} else {
-		/*
-		 * If finalScaleValue is less than or equal to 9, a value of 0 should
-		 * be used to disable the scale increment at the end of the slice
-		 */
-		vdsc_cfg->scale_increment_interval = 0;
-	}
-
-	if (vdsc_cfg->scale_increment_interval > 65535) {
-		DRM_DEBUG_KMS("ScaleIncrementInterval is large for slice height\n");
-		return -ERANGE;
-	}
-
-	/*
-	 * DSC spec mentions that bits_per_pixel specifies the target
-	 * bits/pixel (bpp) rate that is used by the encoder,
-	 * in steps of 1/16 of a bit per pixel
-	 */
-	rbs_min = vdsc_cfg->rc_model_size - vdsc_cfg->initial_offset +
-		DIV_ROUND_UP(vdsc_cfg->initial_xmit_delay *
-			     vdsc_cfg->bits_per_pixel, 16) +
-		groups_per_line * vdsc_cfg->first_line_bpg_offset;
-
-	hrd_delay = DIV_ROUND_UP((rbs_min * 16), vdsc_cfg->bits_per_pixel);
-	vdsc_cfg->rc_bits = (hrd_delay * vdsc_cfg->bits_per_pixel) / 16;
-	vdsc_cfg->initial_dec_delay = hrd_delay - vdsc_cfg->initial_xmit_delay;
-
-	return 0;
-}
-
 int intel_dp_compute_dsc_params(struct intel_dp *intel_dp,
 				struct intel_crtc_state *pipe_config)
 {
@@ -574,7 +451,7 @@ int intel_dp_compute_dsc_params(struct intel_dp *intel_dp,
 	vdsc_cfg->initial_scale_value = (vdsc_cfg->rc_model_size << 3) /
 		(vdsc_cfg->rc_model_size - vdsc_cfg->initial_offset);
 
-	return intel_compute_rc_parameters(vdsc_cfg);
+	return drm_dsc_compute_rc_parameters(vdsc_cfg);
 }
 
 enum intel_display_power_domain

include/drm/drm_dsc.h

@@ -604,5 +604,6 @@ struct drm_dsc_pps_infoframe {
 void drm_dsc_dp_pps_header_init(struct drm_dsc_pps_infoframe *pps_sdp);
 void drm_dsc_pps_infoframe_pack(struct drm_dsc_pps_infoframe *pps_sdp,
 				const struct drm_dsc_config *dsc_cfg);
+int drm_dsc_compute_rc_parameters(struct drm_dsc_config *vdsc_cfg);
 
 #endif /* _DRM_DSC_H_ */