drm/i915/vdsc: Check slice design requirement

Add function to check if slice design requirements are being
met as defined in Bspec: 49259 in the section
Slice Design Requirement

--v7
-remove full bspec link [Jani]
-rename intel_dsc_check_slice_design_req to
intel_dsc_slice_dimensions_valid [Jani]

--v8
-fix condition to check if slice width and height are
of two
-fix minimum pixel in slice condition

--v10
-condition should be < rather then >= [Uma]

Cc: Uma Shankar <[e-mail]>
Signed-off-by: Suraj Kandpal <[e-mail]>
Reviewed-by: Uma Shankar <[e-mail]>
Signed-off-by: Uma Shankar <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

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

···
 	}
 }
 
+static int intel_dsc_slice_dimensions_valid(struct intel_crtc_state *pipe_config,
+					    struct drm_dsc_config *vdsc_cfg)
+{
+	if (pipe_config->output_format == INTEL_OUTPUT_FORMAT_RGB ||
+	    pipe_config->output_format == INTEL_OUTPUT_FORMAT_YCBCR444) {
+		if (vdsc_cfg->slice_height > 4095)
+			return -EINVAL;
+		if (vdsc_cfg->slice_height * vdsc_cfg->slice_width < 15000)
+			return -EINVAL;
+	} else if (pipe_config->output_format == INTEL_OUTPUT_FORMAT_YCBCR420) {
+		if (vdsc_cfg->slice_width % 2)
+			return -EINVAL;
+		if (vdsc_cfg->slice_height % 2)
+			return -EINVAL;
+		if (vdsc_cfg->slice_height > 4094)
+			return -EINVAL;
+		if (vdsc_cfg->slice_height * vdsc_cfg->slice_width < 30000)
+			return -EINVAL;
+	}
+
+	return 0;
+}
+
 int intel_dsc_compute_params(struct intel_crtc_state *pipe_config)
 {
 	struct intel_crtc *crtc = to_intel_crtc(pipe_config->uapi.crtc);
···
 	u16 compressed_bpp = pipe_config->dsc.compressed_bpp;
 	const struct rc_parameters *rc_params;
 	struct rc_parameters *rc = NULL;
+	int err;
 	u8 i = 0;
 
 	vdsc_cfg->pic_width = pipe_config->hw.adjusted_mode.crtc_hdisplay;
 	vdsc_cfg->slice_width = DIV_ROUND_UP(vdsc_cfg->pic_width,
 					     pipe_config->dsc.slice_count);
+
+	err = intel_dsc_slice_dimensions_valid(pipe_config, vdsc_cfg);
+
+	if (err) {
+		drm_dbg_kms(&dev_priv->drm, "Slice dimension requirements not met\n");
+		return err;
+	}
+
 	/*
 	 * According to DSC 1.2 specs if colorspace is YCbCr then convert_rgb is 0
 	 * else 1