freedreno/a6xx: support layered framebuffers in blitter_clear

Clear is done with one instanced draw call, where the layer
to clear is controlled by gl_Layer.
Same as how util_blitter_clear does this.

Fixes test:
gl-3.2-layered-rendering-clear-color-all-types 2d_multisample_array single_level
Signed-off-by: Danylo Piliaiev <dpiliaiev@igalia.com>
Part-of: <mesa/mesa!7919>

src/gallium/drivers/freedreno/freedreno_blitter.c

@@ -222,7 +222,12 @@ fd_blitter_clear(struct pipe_context *pctx, unsigned buffers,
 	pctx->set_vertex_buffers(pctx, blitter->vb_slot, 1,
 			&ctx->solid_vbuf_state.vertexbuf.vb[0]);
 	pctx->set_stream_output_targets(pctx, 0, NULL, NULL);
-	pctx->bind_vs_state(pctx, ctx->solid_prog.vs);
+
+	if (pfb->layers > 1)
+		pctx->bind_vs_state(pctx, ctx->solid_layered_prog.vs);
+	else
+		pctx->bind_vs_state(pctx, ctx->solid_prog.vs);
+
 	pctx->bind_fs_state(pctx, ctx->solid_prog.fs);
 
 	/* Clear geom/tess shaders, lest the draw emit code think we are
@@ -235,7 +240,7 @@ fd_blitter_clear(struct pipe_context *pctx, unsigned buffers,
 	struct pipe_draw_info info = {
 		.mode = PIPE_PRIM_MAX,    /* maps to DI_PT_RECTLIST */
 		.max_index = 1,
-		.instance_count = 1,
+		.instance_count = MAX2(1, pfb->layers),
 	};
         struct pipe_draw_start_count draw = {
                 .count = 2,

src/gallium/drivers/freedreno/freedreno_context.h

@@ -253,6 +253,7 @@ struct fd_context {
 
 	/* shaders used by clear, and gmem->mem blits: */
 	struct fd_program_stateobj solid_prog; // TODO move to screen?
+	struct fd_program_stateobj solid_layered_prog;
 
 	/* shaders used by mem->gmem blits: */
 	struct fd_program_stateobj blit_prog[MAX_RENDER_TARGETS]; // TODO move to screen?

src/gallium/drivers/freedreno/freedreno_program.c

@@ -27,6 +27,8 @@
 #include "tgsi/tgsi_text.h"
 #include "tgsi/tgsi_ureg.h"
 
+#include "util/u_simple_shaders.h"
+
 #include "freedreno_program.h"
 #include "freedreno_context.h"
 
@@ -188,6 +190,12 @@ void fd_prog_init(struct pipe_context *pctx)
 	ctx->solid_prog.fs = assemble_tgsi(pctx, solid_fs, true);
 	ctx->solid_prog.vs = assemble_tgsi(pctx, solid_vs, false);
 
+	if (ctx->screen->gpu_id >= 600) {
+		ctx->solid_layered_prog.fs = assemble_tgsi(pctx, solid_fs, true);
+		ctx->solid_layered_prog.vs =
+			util_make_layered_clear_vertex_shader(pctx);
+	}
+
 	if (ctx->screen->gpu_id >= 500)
 		return;
 
@@ -215,6 +223,12 @@ void fd_prog_fini(struct pipe_context *pctx)
 
 	pctx->delete_vs_state(pctx, ctx->solid_prog.vs);
 	pctx->delete_fs_state(pctx, ctx->solid_prog.fs);
+
+	if (ctx->screen->gpu_id >= 600) {
+		pctx->delete_vs_state(pctx, ctx->solid_layered_prog.vs);
+		pctx->delete_fs_state(pctx, ctx->solid_layered_prog.fs);
+	}
+
 	if (ctx->screen->gpu_id >= 500)
 		return;