i965: Implement GenerateMipmap directly, rather than using Meta.

Meta is awful and we'd like to stop using it.  Implementing this using
BLORP allows us to stop trashing a bunch of GL state every time.

This follows the structure of st_generate_mipmap().
compute_num_levels is lifted directly from there.

Improves performance in Gl41HdrBloom by about 11.794% +/- 1.01919% (n=3)
on Kabylake GT2 at 1280x720 (the difference seems much smaller at higher
resolutions).

v2 (idr): Don't try depth or depth-stencil blorp blits on Gen4 or Gen5
because it's not implemented yet.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Topi Pohjolainen <topi.pohjolainen@intel.com>

src/mesa/drivers/dri/i965/Makefile.sources

@@ -22,6 +22,7 @@ i965_FILES = \
 	brw_ff_gs_emit.c \
 	brw_ff_gs.h \
 	brw_formatquery.c \
+	brw_generate_mipmap.c \
 	brw_gs.c \
 	brw_gs.h \
 	brw_gs_surface_state.c \

src/mesa/drivers/dri/i965/brw_context.c

@@ -303,6 +303,8 @@ brw_init_driver_functions(struct brw_context *brw,
    brw_init_compute_functions(functions);
    brw_init_conditional_render_functions(functions);
 
+   functions->GenerateMipmap = brw_generate_mipmap;
+
    functions->QueryInternalFormat = brw_query_internal_format;
 
    functions->NewTransformFeedback = brw_new_transform_feedback;

src/mesa/drivers/dri/i965/brw_context.h

@@ -1575,6 +1575,10 @@ brw_blorp_copytexsubimage(struct brw_context *brw,
                           int dstX0, int dstY0,
                           int width, int height);
 
+/* brw_generate_mipmap.c */
+void brw_generate_mipmap(struct gl_context *ctx, GLenum target,
+                         struct gl_texture_object *tex_obj);
+
 void
 gen6_get_sample_position(struct gl_context *ctx,
                          struct gl_framebuffer *fb,

src/mesa/drivers/dri/i965/brw_generate_mipmap.c

@@ -0,0 +1,127 @@
+/*
+ * Copyright © 2016 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include "main/mipmap.h"
+#include "main/teximage.h"
+#include "brw_blorp.h"
+#include "brw_context.h"
+#include "intel_tex.h"
+#include "drivers/common/meta.h"
+
+#define FILE_DEBUG_FLAG DEBUG_BLORP
+
+
+/**
+ * The GenerateMipmap() driver hook.
+ */
+void
+brw_generate_mipmap(struct gl_context *ctx, GLenum target,
+                    struct gl_texture_object *tex_obj)
+{
+   struct brw_context *brw = brw_context(ctx);
+   struct gen_device_info *devinfo = &brw->screen->devinfo;
+   struct intel_texture_object *intel_obj = intel_texture_object(tex_obj);
+   const unsigned base_level = tex_obj->BaseLevel;
+   unsigned last_level, first_layer, last_layer;
+
+   /* Blorp doesn't handle combined depth/stencil surfaces on Gen4-5 yet. */
+   if (devinfo->gen <= 5 &&
+       (tex_obj->Image[0][base_level]->_BaseFormat == GL_DEPTH_COMPONENT ||
+        tex_obj->Image[0][base_level]->_BaseFormat == GL_DEPTH_STENCIL)) {
+      _mesa_meta_GenerateMipmap(ctx, target, tex_obj);
+      return;
+   }
+
+   /* find expected last mipmap level to generate */
+   last_level = _mesa_compute_num_levels(ctx, tex_obj, target) - 1;
+
+   if (last_level == 0)
+      return;
+
+   /* The texture isn't in a "complete" state yet so set the expected
+    * last_level here; we're not going through normal texture validation.
+    */
+   intel_obj->_MaxLevel = last_level;
+
+   if (!tex_obj->Immutable) {
+      _mesa_prepare_mipmap_levels(ctx, tex_obj, base_level, last_level);
+
+      /* At this point, memory for all the texture levels has been
+       * allocated.  However, the base level image may be in one resource
+       * while the subsequent/smaller levels may be in another resource.
+       * Finalizing the texture will copy the base images from the former
+       * resource to the latter.
+       *
+       * After this, we'll have all mipmap levels in one resource.
+       */
+      intel_finalize_mipmap_tree(brw, tex_obj);
+   }
+
+   struct intel_mipmap_tree *mt = intel_obj->mt;
+   if (!mt) {
+      _mesa_error(ctx, GL_OUT_OF_MEMORY, "mipmap generation");
+      return;
+   }
+
+   const mesa_format format = intel_obj->_Format;
+
+   /* Fall back to the CPU for non-renderable cases.
+    *
+    * TODO: 3D textures require blending data from multiple slices,
+    * which means we need custom shaders.  For now, fall back.
+    */
+   if (!brw->mesa_format_supports_render[format] || target == GL_TEXTURE_3D) {
+      _mesa_generate_mipmap(ctx, target, tex_obj);
+      return;
+   }
+
+   const struct isl_extent4d *base_size = &mt->surf.logical_level0_px;
+
+   if (mt->target == GL_TEXTURE_CUBE_MAP) {
+      first_layer = _mesa_tex_target_to_face(target);
+      last_layer = first_layer;
+   } else {
+      first_layer = 0;
+      last_layer = base_size->array_len - 1;
+   }
+
+   for (unsigned dst_level = base_level + 1;
+        dst_level <= last_level;
+        dst_level++) {
+
+      const unsigned src_level = dst_level - 1;
+
+      for (unsigned layer = first_layer; layer <= last_layer; layer++) {
+         brw_blorp_blit_miptrees(brw, mt, src_level, layer, format,
+                                 SWIZZLE_XYZW, mt, dst_level, layer, format,
+                                 0, 0,
+                                 minify(base_size->width, src_level),
+                                 minify(base_size->height, src_level),
+                                 0, 0,
+                                 minify(base_size->width, dst_level),
+                                 minify(base_size->height, dst_level),
+                                 GL_LINEAR, false, false,
+                                 true, true);
+      }
+   }
+}

src/mesa/drivers/dri/i965/meson.build

@@ -42,6 +42,7 @@ files_i965 = files(
   'brw_ff_gs_emit.c',
   'brw_ff_gs.h',
   'brw_formatquery.c',
+  'brw_generate_mipmap.c',
   'brw_gs.c',
   'brw_gs.h',
   'brw_gs_surface_state.c',