freedreno: add env var to override tiles-per-pipe

Signed-off-by: Rob Clark <robdclark@chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6461>

src/gallium/drivers/freedreno/freedreno_gmem.c

@@ -24,6 +24,7 @@
  *    Rob Clark <robclark@freedesktop.org>
  */
 
+#include "util/debug.h"
 #include "pipe/p_state.h"
 #include "util/hash_table.h"
 #include "util/u_dump.h"
@@ -326,6 +327,11 @@ gmem_stateobj_init(struct fd_screen *screen, struct gmem_key *key)
 			tpp_x += 1;
 	}
 
+#ifdef DEBUG
+	tpp_x = env_var_as_unsigned("TPP_X", tpp_x);
+	tpp_y = env_var_as_unsigned("TPP_Y", tpp_x);
+#endif
+
 	gmem->maxpw = tpp_x;
 	gmem->maxph = tpp_y;