radeonsi: Implement DCC fast clear.

Uses the DCC buffer instead of the CMASK buffer. The ELIMINATE_FAST_CLEAR
still works. Furthermore, with DCC compression we can directly clear
to a limited set of colors such that we do not need a postprocessing step.

v2 Marek: check dcc_buffer && dirty_level_mask in set_sampler_view

Signed-off-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Signed-off-by: Marek Olšák <marek.olsak@amd.com>

src/gallium/drivers/radeon/r600_texture.c

@@ -1239,6 +1239,81 @@ static void evergreen_set_clear_color(struct r600_texture *rtex,
 	memcpy(rtex->color_clear_value, &uc, 2 * sizeof(uint32_t));
 }
 
+static void vi_get_fast_clear_parameters(enum pipe_format surface_format,
+					 const union pipe_color_union *color,
+					 uint32_t* reset_value,
+					 bool* clear_words_needed)
+{
+	bool values[4] = {};
+	int i;
+	bool main_value = false;
+	bool extra_value = false;
+	int extra_channel;
+	const struct util_format_description *desc = util_format_description(surface_format);
+
+	*clear_words_needed = true;
+	*reset_value = 0x20202020U;
+
+	/* If we want to clear without needing a fast clear eliminate step, we
+	 * can set each channel to 0 or 1 (or 0/max for integer formats). We
+	 * have two sets of flags, one for the last or first channel(extra) and
+	 * one for the other channels(main).
+	 */
+
+	if (surface_format == PIPE_FORMAT_R11G11B10_FLOAT ||
+	    surface_format == PIPE_FORMAT_B5G6R5_UNORM ||
+	    surface_format == PIPE_FORMAT_B5G6R5_SRGB) {
+		extra_channel = -1;
+	} else if (desc->layout == UTIL_FORMAT_LAYOUT_PLAIN) {
+		if(r600_translate_colorswap(surface_format) <= 1)
+			extra_channel = desc->nr_channels - 1;
+		else
+			extra_channel = 0;
+	} else
+		return;
+
+	for (i = 0; i < 4; ++i) {
+		int index = desc->swizzle[i] - UTIL_FORMAT_SWIZZLE_X;
+
+		if (desc->swizzle[i] < UTIL_FORMAT_SWIZZLE_X ||
+		    desc->swizzle[i] > UTIL_FORMAT_SWIZZLE_W)
+			continue;
+
+		if (util_format_is_pure_sint(surface_format)) {
+			values[i] = color->i[i] != 0;
+			if (color->i[i] != 0 && color->i[i] != INT32_MAX)
+				return;
+		} else if (util_format_is_pure_uint(surface_format)) {
+			values[i] = color->ui[i] != 0U;
+			if (color->ui[i] != 0U && color->ui[i] != UINT32_MAX)
+				return;
+		} else {
+			values[i] = color->f[i] != 0.0F;
+			if (color->f[i] != 0.0F && color->f[i] != 1.0F)
+				return;
+		}
+
+		if (index == extra_channel)
+			extra_value = values[i];
+		else
+			main_value = values[i];
+	}
+
+	for (int i = 0; i < 4; ++i)
+		if (values[i] != main_value &&
+		    desc->swizzle[i] - UTIL_FORMAT_SWIZZLE_X != extra_channel &&
+		    desc->swizzle[i] >= UTIL_FORMAT_SWIZZLE_X &&
+		    desc->swizzle[i] <= UTIL_FORMAT_SWIZZLE_W)
+			return;
+
+	*clear_words_needed = false;
+	if (main_value)
+		*reset_value |= 0x80808080U;
+
+	if (extra_value)
+		*reset_value |= 0x40404040U;
+}
+
 void evergreen_do_fast_color_clear(struct r600_common_context *rctx,
 				   struct pipe_framebuffer_state *fb,
 				   struct r600_atom *fb_state,
@@ -1292,23 +1367,33 @@ void evergreen_do_fast_color_clear(struct r600_common_context *rctx,
 			continue;
 		}
 
-		/* CMASK clear does not work for DCC compressed textures */
 		if (tex->surface.dcc_enabled) {
-			continue;
+			uint32_t reset_value;
+			bool clear_words_needed;
+
+			vi_get_fast_clear_parameters(fb->cbufs[i]->format, color, &reset_value, &clear_words_needed);
+
+			rctx->clear_buffer(&rctx->b, &tex->dcc_buffer->b.b,
+					0, tex->surface.dcc_size, reset_value, true);
+
+			if (clear_words_needed)
+				tex->dirty_level_mask |= 1 << fb->cbufs[i]->u.tex.level;
+		} else {
+			/* ensure CMASK is enabled */
+			r600_texture_alloc_cmask_separate(rctx->screen, tex);
+			if (tex->cmask.size == 0) {
+				continue;
+			}
+
+			/* Do the fast clear. */
+			rctx->clear_buffer(&rctx->b, &tex->cmask_buffer->b.b,
+					tex->cmask.offset, tex->cmask.size, 0, true);
+
+			tex->dirty_level_mask |= 1 << fb->cbufs[i]->u.tex.level;
 		}
 
-		/* ensure CMASK is enabled */
-		r600_texture_alloc_cmask_separate(rctx->screen, tex);
-		if (tex->cmask.size == 0) {
-			continue;
-		}
-
-		/* Do the fast clear. */
 		evergreen_set_clear_color(tex, fb->cbufs[i]->format, color);
-		rctx->clear_buffer(&rctx->b, &tex->cmask_buffer->b.b,
-				   tex->cmask.offset, tex->cmask.size, 0, true);
 
-		tex->dirty_level_mask |= 1 << fb->cbufs[i]->u.tex.level;
 		if (dirty_cbufs)
 			*dirty_cbufs |= 1 << i;
 		rctx->set_atom_dirty(rctx, fb_state, true);

src/gallium/drivers/radeonsi/si_blit.c

@@ -326,7 +326,7 @@ void si_decompress_color_textures(struct si_context *sctx,
 		assert(view);
 
 		tex = (struct r600_texture *)view->texture;
-		assert(tex->cmask.size || tex->fmask.size);
+		assert(tex->cmask.size || tex->fmask.size || tex->surface.dcc_enabled);
 
 		si_blit_decompress_color(&sctx->b.b, tex,
 					 view->u.tex.first_level, view->u.tex.last_level,
@@ -455,7 +455,7 @@ static void si_decompress_subresource(struct pipe_context *ctx,
 			si_blit_decompress_depth_in_place(sctx, rtex, true,
 							  level, level,
 							  first_layer, last_layer);
-	} else if (rtex->fmask.size || rtex->cmask.size) {
+	} else if (rtex->fmask.size || rtex->cmask.size || rtex->surface.dcc_enabled) {
 		si_blit_decompress_color(ctx, rtex, level, level,
 					 first_layer, last_layer);
 	}

src/gallium/drivers/radeonsi/si_descriptors.c

@@ -234,7 +234,8 @@ static void si_set_sampler_views(struct pipe_context *ctx,
 			} else {
 				samplers->depth_texture_mask &= ~(1 << slot);
 			}
-			if (rtex->cmask.size || rtex->fmask.size) {
+			if (rtex->cmask.size || rtex->fmask.size ||
+			    (rtex->dcc_buffer && rtex->dirty_level_mask)) {
 				samplers->compressed_colortex_mask |= 1 << slot;
 			} else {
 				samplers->compressed_colortex_mask &= ~(1 << slot);