drm/i915/display: Store compressed bpp in U6.4 format

DSC parameter bits_per_pixel is stored in U6.4 format.
The 4 bits represent the fractional part of the bpp.
Currently we use compressed_bpp member of dsc structure to store
only the integral part of the bits_per_pixel.
To store the full bits_per_pixel along with the fractional part,
compressed_bpp is changed to store bpp in U6.4 formats. Intergral
part is retrieved by simply right shifting the member compressed_bpp by 4.

v2:
-Use to_bpp_int, to_bpp_frac_dec, to_bpp_x16 helpers while dealing
 with compressed bpp. (Suraj)
-Fix comment styling. (Suraj)

v3:
-Add separate file for 6.4 fixed point helper(Jani, Nikula)
-Add comment for magic values(Suraj)

v4:
-Fix checkpatch warnings caused by renaming(Suraj)

v5:
-Rebase.
-Use existing helpers for conversion of bpp_int to bpp_x16
 and vice versa.
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
Reviewed-by: Suraj Kandpal <suraj.kandpal@intel.com>
Reviewed-by: Sui Jingfeng <suijingfeng@loongson.cn>
Link: https://patchwork.freedesktop.org/patch/msgid/20231110101020.4067342-3-ankit.k.nautiyal@intel.com

drivers/gpu/drm/i915/display/icl_dsi.c

@@ -330,7 +330,7 @@ static int afe_clk(struct intel_encoder *encoder,
 	int bpp;
 
 	if (crtc_state->dsc.compression_enable)
-		bpp = crtc_state->dsc.compressed_bpp;
+		bpp = to_bpp_int(crtc_state->dsc.compressed_bpp_x16);
 	else
 		bpp = mipi_dsi_pixel_format_to_bpp(intel_dsi->pixel_format);
 
@@ -860,7 +860,7 @@ gen11_dsi_set_transcoder_timings(struct intel_encoder *encoder,
 	 * compressed and non-compressed bpp.
 	 */
 	if (crtc_state->dsc.compression_enable) {
-		mul = crtc_state->dsc.compressed_bpp;
+		mul = to_bpp_int(crtc_state->dsc.compressed_bpp_x16);
 		div = mipi_dsi_pixel_format_to_bpp(intel_dsi->pixel_format);
 	}
 
@@ -884,7 +884,7 @@ gen11_dsi_set_transcoder_timings(struct intel_encoder *encoder,
 		int bpp, line_time_us, byte_clk_period_ns;
 
 		if (crtc_state->dsc.compression_enable)
-			bpp = crtc_state->dsc.compressed_bpp;
+			bpp = to_bpp_int(crtc_state->dsc.compressed_bpp_x16);
 		else
 			bpp = mipi_dsi_pixel_format_to_bpp(intel_dsi->pixel_format);
 
@@ -1451,8 +1451,8 @@ static void gen11_dsi_get_timings(struct intel_encoder *encoder,
 	struct drm_display_mode *adjusted_mode =
 					&pipe_config->hw.adjusted_mode;
 
-	if (pipe_config->dsc.compressed_bpp) {
-		int div = pipe_config->dsc.compressed_bpp;
+	if (pipe_config->dsc.compressed_bpp_x16) {
+		int div = to_bpp_int(pipe_config->dsc.compressed_bpp_x16);
 		int mul = mipi_dsi_pixel_format_to_bpp(intel_dsi->pixel_format);
 
 		adjusted_mode->crtc_htotal =

drivers/gpu/drm/i915/display/intel_audio.c

@@ -528,7 +528,7 @@ static unsigned int calc_hblank_early_prog(struct intel_encoder *encoder,
 	h_active = crtc_state->hw.adjusted_mode.crtc_hdisplay;
 	h_total = crtc_state->hw.adjusted_mode.crtc_htotal;
 	pixel_clk = crtc_state->hw.adjusted_mode.crtc_clock;
-	vdsc_bpp = crtc_state->dsc.compressed_bpp;
+	vdsc_bpp = to_bpp_int(crtc_state->dsc.compressed_bpp_x16);
 	cdclk = i915->display.cdclk.hw.cdclk;
 	/* fec= 0.972261, using rounding multiplier of 1000000 */
 	fec_coeff = 972261;

drivers/gpu/drm/i915/display/intel_bios.c

@@ -3414,8 +3414,8 @@ static void fill_dsc(struct intel_crtc_state *crtc_state,
 
 	crtc_state->pipe_bpp = bpc * 3;
 
-	crtc_state->dsc.compressed_bpp = min(crtc_state->pipe_bpp,
-					     VBT_DSC_MAX_BPP(dsc->max_bpp));
+	crtc_state->dsc.compressed_bpp_x16 = to_bpp_x16(min(crtc_state->pipe_bpp,
+							    VBT_DSC_MAX_BPP(dsc->max_bpp)));
 
 	/*
 	 * FIXME: This is ugly, and slice count should take DSC engine

drivers/gpu/drm/i915/display/intel_cdclk.c

@@ -2598,8 +2598,9 @@ static int intel_vdsc_min_cdclk(const struct intel_crtc_state *crtc_state)
 		 * => CDCLK >= compressed_bpp * Pixel clock  / 2 * Bigjoiner Interface bits
 		 */
 		int bigjoiner_interface_bits = DISPLAY_VER(i915) > 13 ? 36 : 24;
-		int min_cdclk_bj = (crtc_state->dsc.compressed_bpp * pixel_clock) /
-				   (2 * bigjoiner_interface_bits);
+		int min_cdclk_bj =
+			(to_bpp_int_roundup(crtc_state->dsc.compressed_bpp_x16) *
+			 pixel_clock) / (2 * bigjoiner_interface_bits);
 
 		min_cdclk = max(min_cdclk, min_cdclk_bj);
 	}

drivers/gpu/drm/i915/display/intel_display.c

@@ -5434,7 +5434,7 @@ intel_pipe_config_compare(const struct intel_crtc_state *current_config,
 
 	PIPE_CONF_CHECK_I(dsc.compression_enable);
 	PIPE_CONF_CHECK_I(dsc.dsc_split);
-	PIPE_CONF_CHECK_I(dsc.compressed_bpp);
+	PIPE_CONF_CHECK_I(dsc.compressed_bpp_x16);
 
 	PIPE_CONF_CHECK_BOOL(splitter.enable);
 	PIPE_CONF_CHECK_I(splitter.link_count);

drivers/gpu/drm/i915/display/intel_display_types.h

@@ -1363,7 +1363,8 @@ struct intel_crtc_state {
 	struct {
 		bool compression_enable;
 		bool dsc_split;
-		u16 compressed_bpp;
+		/* Compressed Bpp in U6.4 format (first 4 bits for fractional part) */
+		u16 compressed_bpp_x16;
 		u8 slice_count;
 		struct drm_dsc_config config;
 	} dsc;

drivers/gpu/drm/i915/display/intel_dp.c

@@ -1885,7 +1885,8 @@ icl_dsc_compute_link_config(struct intel_dp *intel_dp,
 					      valid_dsc_bpp[i],
 					      timeslots);
 		if (ret == 0) {
-			pipe_config->dsc.compressed_bpp = valid_dsc_bpp[i];
+			pipe_config->dsc.compressed_bpp_x16 =
+				to_bpp_x16(valid_dsc_bpp[i]);
 			return 0;
 		}
 	}
@@ -1923,7 +1924,8 @@ xelpd_dsc_compute_link_config(struct intel_dp *intel_dp,
 					      compressed_bpp,
 					      timeslots);
 		if (ret == 0) {
-			pipe_config->dsc.compressed_bpp = compressed_bpp;
+			pipe_config->dsc.compressed_bpp_x16 =
+				to_bpp_x16(compressed_bpp);
 			return 0;
 		}
 	}
@@ -2120,7 +2122,8 @@ static int intel_edp_dsc_compute_pipe_bpp(struct intel_dp *intel_dp,
 	/* Compressed BPP should be less than the Input DSC bpp */
 	dsc_max_bpp = min(dsc_max_bpp, pipe_bpp - 1);
 
-	pipe_config->dsc.compressed_bpp = max(dsc_min_bpp, dsc_max_bpp);
+	pipe_config->dsc.compressed_bpp_x16 =
+		to_bpp_x16(max(dsc_min_bpp, dsc_max_bpp));
 
 	pipe_config->pipe_bpp = pipe_bpp;
 
@@ -2209,18 +2212,18 @@ int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
 	ret = intel_dp_dsc_compute_params(connector, pipe_config);
 	if (ret < 0) {
 		drm_dbg_kms(&dev_priv->drm,
-			    "Cannot compute valid DSC parameters for Input Bpp = %d "
-			    "Compressed BPP = %d\n",
+			    "Cannot compute valid DSC parameters for Input Bpp = %d"
+			    "Compressed BPP = " BPP_X16_FMT "\n",
 			    pipe_config->pipe_bpp,
-			    pipe_config->dsc.compressed_bpp);
+			    BPP_X16_ARGS(pipe_config->dsc.compressed_bpp_x16));
 		return ret;
 	}
 
 	pipe_config->dsc.compression_enable = true;
 	drm_dbg_kms(&dev_priv->drm, "DP DSC computed with Input Bpp = %d "
-		    "Compressed Bpp = %d Slice Count = %d\n",
+		    "Compressed Bpp = " BPP_X16_FMT " Slice Count = %d\n",
 		    pipe_config->pipe_bpp,
-		    pipe_config->dsc.compressed_bpp,
+		    BPP_X16_ARGS(pipe_config->dsc.compressed_bpp_x16),
 		    pipe_config->dsc.slice_count);
 
 	return 0;
@@ -2393,15 +2396,15 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
 
 	if (pipe_config->dsc.compression_enable) {
 		drm_dbg_kms(&i915->drm,
-			    "DP lane count %d clock %d Input bpp %d Compressed bpp %d\n",
+			    "DP lane count %d clock %d Input bpp %d Compressed bpp " BPP_X16_FMT "\n",
 			    pipe_config->lane_count, pipe_config->port_clock,
 			    pipe_config->pipe_bpp,
-			    pipe_config->dsc.compressed_bpp);
+			    BPP_X16_ARGS(pipe_config->dsc.compressed_bpp_x16));
 
 		drm_dbg_kms(&i915->drm,
 			    "DP link rate required %i available %i\n",
 			    intel_dp_link_required(adjusted_mode->crtc_clock,
-						   pipe_config->dsc.compressed_bpp),
+						   to_bpp_int_roundup(pipe_config->dsc.compressed_bpp_x16)),
 			    intel_dp_max_data_rate(pipe_config->port_clock,
 						   pipe_config->lane_count));
 	} else {
@@ -2863,7 +2866,7 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 		drm_dp_enhanced_frame_cap(intel_dp->dpcd);
 
 	if (pipe_config->dsc.compression_enable)
-		link_bpp = pipe_config->dsc.compressed_bpp;
+		link_bpp = to_bpp_int(pipe_config->dsc.compressed_bpp_x16);
 	else
 		link_bpp = intel_dp_output_bpp(pipe_config->output_format,
 					       pipe_config->pipe_bpp);

drivers/gpu/drm/i915/display/intel_dp_mst.c

@@ -228,7 +228,7 @@ static int intel_dp_mst_find_vcpi_slots_for_bpp(struct intel_encoder *encoder,
 		if (!dsc)
 			crtc_state->pipe_bpp = bpp;
 		else
-			crtc_state->dsc.compressed_bpp = bpp;
+			crtc_state->dsc.compressed_bpp_x16 = to_bpp_x16(bpp);
 		drm_dbg_kms(&i915->drm, "Got %d slots for pipe bpp %d dsc %d\n", slots, bpp, dsc);
 	}
 

drivers/gpu/drm/i915/display/intel_link_bw.c

@@ -70,7 +70,7 @@ int intel_link_bw_reduce_bpp(struct intel_atomic_state *state,
 			return PTR_ERR(crtc_state);
 
 		if (crtc_state->dsc.compression_enable)
-			link_bpp = crtc_state->dsc.compressed_bpp;
+			link_bpp = crtc_state->dsc.compressed_bpp_x16;
 		else
 			/*
 			 * TODO: for YUV420 the actual link bpp is only half

drivers/gpu/drm/i915/display/intel_vdsc.c

@@ -248,7 +248,7 @@ int intel_dsc_compute_params(struct intel_crtc_state *pipe_config)
 	struct intel_crtc *crtc = to_intel_crtc(pipe_config->uapi.crtc);
 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
 	struct drm_dsc_config *vdsc_cfg = &pipe_config->dsc.config;
-	u16 compressed_bpp = pipe_config->dsc.compressed_bpp;
+	u16 compressed_bpp = to_bpp_int(pipe_config->dsc.compressed_bpp_x16);
 	int err;
 	int ret;
 
@@ -874,7 +874,7 @@ static void intel_dsc_get_pps_config(struct intel_crtc_state *crtc_state)
 	if (vdsc_cfg->native_420)
 		vdsc_cfg->bits_per_pixel >>= 1;
 
-	crtc_state->dsc.compressed_bpp = vdsc_cfg->bits_per_pixel >> 4;
+	crtc_state->dsc.compressed_bpp_x16 = vdsc_cfg->bits_per_pixel;
 
 	/* PPS 2 */
 	pps_temp = intel_dsc_pps_read_and_verify(crtc_state, 2);