agx: Add scaffolding to build the helper shader at device init

Add the scaffolding to compile our helper program, and load it at device
init time.

Signed-off-by: Asahi Lina <lina@asahilina.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/27616>

src/asahi/lib/agx_device.c

@@ -9,6 +9,7 @@
 #include "util/timespec.h"
 #include "agx_bo.h"
 #include "agx_compile.h"
+#include "agx_scratch.h"
 #include "decode.h"
 #include "glsl_types.h"
 #include "libagx_shaders.h"
@@ -348,12 +349,17 @@ agx_open_device(void *memctx, struct agx_device *dev)
                     sizeof(libagx_shaders_nir));
    dev->libagx = nir_deserialize(memctx, &agx_nir_options, &blob);
 
+   dev->helper = agx_build_helper(dev);
+
    return true;
 }
 
 void
 agx_close_device(struct agx_device *dev)
 {
+   if (dev->helper)
+      agx_bo_unreference(dev->helper);
+
    agx_bo_cache_evict_all(dev);
    util_sparse_array_finish(&dev->bo_map);
 

src/asahi/lib/agx_device.h

@@ -117,6 +117,8 @@ struct agx_device {
       /* Number of hits/misses for the BO cache */
       uint64_t hits, misses;
    } bo_cache;
+
+   struct agx_bo *helper;
 };
 
 bool agx_open_device(void *memctx, struct agx_device *dev);

src/asahi/lib/agx_scratch.c

@@ -0,0 +1,52 @@
+/*
+ * Copyright 2023 Asahi Lina
+ * SPDX-License-Identifier: MIT
+ */
+
+#include "agx_scratch.h"
+#include "asahi/compiler/agx_compile.h"
+#include "agx_bo.h"
+#include "libagx_shaders.h"
+#include "nir.h"
+#include "nir_builder_opcodes.h"
+
+struct agx_bo *
+agx_build_helper(struct agx_device *dev)
+{
+   struct agx_bo *bo;
+   struct util_dynarray binary;
+
+   util_dynarray_init(&binary, NULL);
+
+   nir_builder b = nir_builder_init_simple_shader(
+      MESA_SHADER_COMPUTE, &agx_nir_options, "Helper shader");
+
+   libagx_helper(&b);
+
+   UNUSED struct agx_uncompiled_shader_info info;
+   UNUSED struct agx_shader_info compiled_info;
+   struct agx_shader_key key = {.libagx = dev->libagx};
+
+   agx_preprocess_nir(b.shader, dev->libagx, false, &info);
+   agx_compile_shader_nir(b.shader, &key, NULL, &binary, &compiled_info);
+
+   bo = agx_bo_create(dev, binary.size,
+                      AGX_BO_READONLY | AGX_BO_EXEC | AGX_BO_LOW_VA,
+                      "Helper shader");
+   assert(bo);
+   memcpy(bo->ptr.cpu, binary.data, binary.size);
+   util_dynarray_fini(&binary);
+   ralloc_free(b.shader);
+
+   return bo;
+}
+
+void
+agx_scratch_init(struct agx_device *dev, struct agx_scratch *scratch)
+{
+}
+
+void
+agx_scratch_fini(struct agx_scratch *scratch)
+{
+}

src/asahi/lib/agx_scratch.h

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2023 Asahi Lina
+ * SPDX-License-Identifier: MIT
+ */
+#ifndef AGX_SCRATCH_H
+#define AGX_SCRATCH_H
+
+#include "agx_device.h"
+
+struct agx_scratch {
+   struct agx_device *dev;
+   struct agx_bo *buf;
+};
+
+struct agx_bo *agx_build_helper(struct agx_device *dev);
+
+void agx_scratch_init(struct agx_device *dev, struct agx_scratch *scratch);
+void agx_scratch_fini(struct agx_scratch *scratch);
+
+#endif

src/asahi/lib/meson.build

@@ -22,6 +22,7 @@ libasahi_lib_files = files(
   'agx_nir_lower_vbo.c',
   'agx_nir_predicate_layer_id.c',
   'agx_ppp.h',
+  'agx_scratch.c',
   'pool.c',
 )
 
@@ -36,6 +37,7 @@ libagx_shader_files = files(
   'shaders/tessellation.cl',
   'shaders/tessellator.cl',
   'shaders/texture.cl',
+  'shaders/helper.cl',
 )
 
 agx_pack = custom_target(

src/asahi/lib/shaders/helper.cl

@@ -0,0 +1,14 @@
+/*
+ * Copyright 2023 Asahi Lina
+ * SPDX-License-Identifier: MIT
+ */
+#include "libagx.h"
+
+#define DB_NEXT   32
+#define DB_ACK    48
+#define DB_NACK   49
+
+void
+libagx_helper(void)
+{
+}